National Onion (and other Allium) Research Conference

Transcription

f 998 National Onion
(and other Allium)
Research Conference
Sacramento,
California, USA
y
and Information Center
University of California, Davis
http:flvricMCdavis.edu
.' •■ ..•■(•. '•■ •.
: ^*5M .
I^SRI
Organizing Committee
AI Burkett, Seminis Vegetable Seeds
Roy "Tule" Kreizenbeck, Rio Colorado Seeds, Inc.
Tom Ikesaki, Empire Research
David Visher, Vegetable Research and Information Center, UCD
Kitty Schlosser, Vegetable Research and Information Center, UCD
Ron Voss, Vegetable Crops Department, UCDavis (Chair)
Sponsors
f
m
Asgrow Vegetable Seeds
Basic Vegetable Products
Christopher Ranch
Colusa Produce Company
Crookham Seed Company
De Francesco Company & Sons, Inc.
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Emerald Seed Company
Empire Research
Gilroy Festival Foods, Gilroy CA
Gilroy Foods .
Onion World Magazine
Rio Colorado Seed Company
Rio Farms
Seed Dynamics, Inc.
Seminis Vegetable Seeds
Shamrock Seed Company
Snow Seed Company
Sunseeds
PROGRAM and ABSTRACTS
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National Onion (and other Allium) Research Conference
December 10-12,1998
Sacramento, California
.;.
7
WEDNESDAYDecembet 9 . ,„.
_
£5f
THURSDAY,December 10 .i,
5 - 7:00 p.m. Conference Registration at the Radisson Hotel in the Hospitality Suite, Room 121
f"
;
£--
7:00 a.m.
Conference Registration and Continental Breakfast in the Conference Center - Pavilion Room
8:00 am.
Opening, Welcome - Conference Center - Room 302
ORAL PRESENTATIONS
Session 1A: Breeding and Genetics - Conference Center - Room 302
8: IS a.m.
_
History and pedigree of publicly-released onion germplasm in the United States during the 20th
century - LL. Goldman and M J. Havey, Department of Horticulture, and USDA-ARS, Department of
Horticulture, University of Wisconsin-Madison, Wisconsin (1)
8:45 am.
Cytoplasms used commercially to produce hybrid onion - MJ. Havey, USDA. ARS. Department of
„
9:00 a.m.
The USDA onion breeding program: new releases and new directions - M.J. Havey, USDA, ARS,
Department of Horticulture, University of Wisconsin-Madison, Wisconsin (3)
915 a.m.
Onion breeding for the dehydration industry in Argentina - Claudio R. Galmarini. La Consulta.
Mendoza, Argentina and Department of Horticulture, University of Wisconsin-Madison, Wisconsin (4)
TO
9:30 am.
9:45 a.m.:
Screening of onions for ability to produce large, mild bulbs in New York - B. L, Phillips, L. A.
Ellcrbrock, and A. Pappas. Department of Fruit and Vegetable Science, Cornell University, Ithaca, New York (5)
Break - Conference Center - Pavillion Room
Session IB: Breeding and Genetics (Continued) - Conference Center - Room 302
10: IS am.
1S3-
Onion breeding research at New Mexico State University - Christopher S. Cramer. Marisa M. Wall and
Joe N. Corgan, Department of Agronomy and Horticulture, New Mexico State University, New Mexico (6)
10:45 a.m. Analyses of recombinant Allium cepa x A. fisiulosum backcross individuals - Anfu Hou, Ellen B.
1
Pcfiley, Department of Plant & Soil Science. Texas Tech University (7)
11:00 am
Estimation of quantitative trait loci controlling solid content, pungency, and antiplatelet activity of
onion (Allium cepa L.) - Claudio R. Galmarini, I Goldman, and M. J. Havey. USDA-ARS and Department of
U:l5a.m.
RFLP and FISH analysis of advanced backcrosses of in Allium interspecific hybrid (Allium cepax
Allium fistulosum) to Allium cepa - Eduardo Villanueva-Moiqueda and Michael J. Havey, USDA-ARS and
Department of Horticulture. University of Wisconsin-Madison. Wisconsin (9)
frr
11:30 a.m.
Molecular-facilitated selection of maintainer lines in onion • All Fuai Cokce and Michael J. Havey.
11:45 a.m.
Transformation of onion (Allium cepa L.) - Eady C.C., R.J. Weld, and C.E. Lister, New Zealand Institute
USDA-ARS and Department of Horticulture, University of Wisconsin-Madison, Wisconsin (10)
o#i
for Crop and Food Research Ltd . Christchurch, New Zealand (11)
12 noon.
"^
Lynclj- Conference Center - Pavillion Room and Room 304
University of California. Davu
Program Page I
Session 1C: Breeding and Genetics (Continued) - Conference Center - Room 302
1:00 p.m.
Direct somatic organogenesis induced on mature onion ovaries or flowers - Bonn Bohanec, Zlaia
Lulhar, University of Ljubljana. Biotechitical Faculty, Centre for Plant Biotechnology and Breeding, Jamnikarjeva.
Slovenia (12)
1:15 p.m.
Molecular analysis of cytoplasmic diversity in leek - Danicla Lopez Uitc and Michael J. Havcy. USDAARS and Department of Horticulture, University of Wisconsin-Madison, Wisconsin (13)
1:30 p.m. First report on storage longevity and genetic diversity of the USDA garlic (A. salivum) collection
- Richard llannan and Barbara Hellicr, USDA-ARS. Western Regional Plant Introduction Station, Washington
State University, Pullman. Washington (14)
1:4S p.m.
Genetic diversity in garlic (AIlium salivum L) as assessed by amplified fragment length
polymorphism (AFLP) - Meryem Ipek and Philipp W. Simon, USDA-ARS, Vegetable Crops, Department of
2:00 p.m.
Microprojectile bombardment of garlic, Allium sativum L. - J. Michele Myers and Philipp W. Simon,
USDA-ARS, Vegetable Crops. Department or Horticulture, University of Wisconsin-Madison, Wisconsin (16)
Session 2:
2:15pm
Seed Production - Conference Center - Room 302
The effects of hybrid onion floral characteristics on honey bee activity - Bill B. Dean and Erin M.
Silva, Department of Horticulture and Landscape Architecture. Washington Stale University, Prosser, Washington
(17)
2:30 p.m.
Onion seed production in the lower Sacramento Valley - Mike Murray and Ron Voss, Farm
Advisor/County Director, University of California-Cooperative Extension. Colusa County and Vegetable Specialist.
University of California. Davis (18)
2:45 p.m.
Effect of harvest practices on seed quality of three onion hybrid varieties - Ron Von. Mike Murray.
Kent Bradford, Herb Phillips. Jim Thompson, Vegetable Specialist, University of California-Cooperative Extension,
Colusa County, Vegetable Crops Department, Agricultural and Biological Engineering Department. University of
California, Davis (19)
3:00 p,m.; Break - POSTER SESSION-|r- Conference Center - Pavillion Room
Session 3A: Flavor, Human Health and Nutrition - Conference Center - Room 302
3:30 p.m
A review of the regulation of sulfur metabolism and its effect on quality in onions and garlic - Jane
E. Lancaster, Martin L Shaw. Meeghan D. Pilher, Julie P. Farrant and John A. McCallum. New Zealand Institute
for Crop and Food Research. Chrisichurch. New Zealand (20)
3:45 p.m.
Nitrogen and its interaction with sulfur will affect onion flavors • William M. Handle, Department of
Horticulture, University of Georgia, Athens, Georgia (21)
4:00 p.m.
Probing further into the nature of onion flavor development during storage - David E. Kopsell and
William M. Randle, University of Georgia, Department of Horticulture, Athens, Georgia (22)
4:15 p.m. Juice extraction methods make difference in pungency estimation of onion - Brian K. Hamilton, Kil
Sun Yoo. and Leonard M. Pike. Vegetable Improvement Center. Department of Horticultural Sciences, Texas A&M
University, College Station. Texas (23)
4:30 p.m.
Considerations for implementing pungency field testing and its practical implications - William M.
Randle, D.E. Kopsell, DA Kopsell, Department of Horticulture. University of Georgia. Athens. Georgia (24)
4:45 p.m.
Development of an automated system for pyruvic acid analysis • Kil Sun Yoo and Leonard M Pike.
Vegetable Improvement Center, Department of Horticultural Sciences, Texas A&M University, College Station,
Texas (25)
5:00 p.tpi Adjourn
6:00 p.m.
Busses leave for Banquet
6:30 • 10 p.m.
Banquet • Heidrick Ag History Center, Woodland
Speaker • Irwin Goldman, "From Pharaohs to Free Radicals: 5,000 Years of AJIiums and
Human Well-Being"
Univcnity ofCttiTomia, Davn
Program Pigc 2
FBWAY, December 11
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7:00 a.m.
Conference Registration and Continental Breakfast in the Conference Center - Pavilion Room
Session 3B: Flavor, Human Health and Nutrition (Continued) - Conference Center Room 302
m
8:00 am
A Comparison of Onion-induced Platelet Aggregation by Plasma or Whole Blood Aggregometry -
8:1S a.m.
The forms of selenium delivered by onions to human diet • Dean A. Kopscll and William M. Randlc,
,
K. S. Orvis. C. R. Galmarini, I. L. Goldman and M. J. Havcy, University or Wisconsin-Madison, Wisconsin (26)
University of Georgia, Dcpamnent of Honicullurc, Athens, Georgia (27)
p,
8:30 a.m.
;
Designing the ultimate onion for human health - Leonard Pike, Kil Sun Yoo. Roger Horn, and Carmen
Lander, Vegetable Improvement Center, Department of Horticultural Sciences, Texas A&M University, College
Station, Texas (28)
8:45 a.m.
ym
Opportunities to market garlic based on health outcomes: alliin, a cholesterol-lowering compound
- S.J. Sterling and DR. Eagling. Institute for Horticultural Development (Agriculture Victoria), Victoria, Australia
(29)
m
Session 4A: Pest Management - Conference Center - Room 302
9:00 a.m. Summary of white rot research presented at the 2"* Int. Symposium on Edible Alliaceae (1997,
Australia), and at the 6th Int. Workshop on Allium White Rot (1998, Mexico) - Fred Crowe and Mary
Ruth McDonald, Central Oregon Agr. Res. Center, Oregon Slate University. Madras Oregon and University of
Guelph, Muck Crops Research Station, Kcilleby. Ontario, Canada (30)
f™
9:30 a.m.
Screening onion lines for resistance to white rot (Sclerolium cepivorum) and onion maggot fly
(Delia antiqua) - MHY llovius. MR McDonald, S Janse and K Vander Kooi. University of Guelph, Muck Crops
Research Station, Kettlcby. Ontario. Canada (31)
9:45 a.m.
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An analysis of the growth and reproduction of Sclerolium cepivorum on Allium crops in relation to
traditional fungicide use and white rot incidence - Fred Crowe, Central Oregon Agr. Res. Center. Oregon
State University, Madras, Oregon (32)
p_
10:00 a.m.^J Break - Conference Center - Pavillion Room
Session 4B: Pest Management (Continued) - Conference Center - Room 302
10:30 a.m Present status of bacterial diseases of onion and their control in New York -James W. Lcrbeerand
w
Norman A. Gunderslicim. Department of Plant Pathology. Cornell University. Ithaca. New York (33)
10:45 a.m. Onion bacterial disease management in Colorado - Howard F. Schwartz and Kristen J. Otto. Colorado
State University, Dept. or Bioagr. Sci. & Pest Mgml. Fort Collins. Colorado (34)
11 00 a.m. Evaluation of fungicides and priming of seed for the control of onion smut, Urocyslis cepulae
""*
S
Frost, on onions - M R McDonald. S. Jansc and K Van der Kooi. Univ. of Guelph, Muck Crops Research
Station, Kctllcby, Ontario. Canada (35)
11:15 a.m. Synthetic germination stimulants decrease incidence of smut (Urocystis cepulae Frost) on onions -
m
:
m.
MR McDonald and MHY Hovius, Univ. of Guelph. Muck Crops Research Station, Keuleby, Ontario, Canada (36)
11 30 a.m. Towards improved control of botrytis leaf blight of onion - M. A. Mutschlcr, E. D. Cobb. J. W. Lorbccr.
Dept. of Plant Breeding and Dept of Plant Pathology. Cornell University. Itliaca. New York (37)
11:45 a.m. Susceptibility of onion seed stalks and flowers to infection by Aspergillus niger Teigh - Karen L.
Sirois and James W. Lorbcer, Department of Plant Pathology. Cornell University, Ithaca. New York (38)
12:00 n^jj^LunchrBUsiness meeting?- Main Hotel - Ballroom F
Univenity of California, Davit
Progrsm Page 3
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Session 4C: Pest Management (Continued) - Conference Center - Room 302
1:00 p.m Garlic seed clove treatments for the control of penicillium decay - R. M. Davis. B. L. Teviotdale. J. J.
Nunez, and N. C. Goodcll. University of California-Cooperative Extension. Davis, Kearney Ag Center, and Kqrn
1: 15 p.m.
County (39)
Severe outbreak of garlic rust disease in California - S. T. Koike. R. F. Smith, R. M. Davis, J. Nunez,
University of California-Cooperative Extension. Monterey County, San Bcnito County. Department of Plant
Pathology, University of California, Davis. University of California-Cooperative Extension, Kern County (40)
1:30 p.m. Damage threshold for thrips on processing onions in the San Joaquin Valley, California - Richard L.
Coviello and Milton E. McGiffen. Jr.. University of California Cooperative Extension. Fresno County and Dept,
Botany and Plant Sciences. University of California, Riverside (41)
1:45 p.m.
Evaluation of treatments for onion thrips control - Ronald F. L. Mau and Laura Gusukuma-Minuto,
Department of Entomology, University of Hawaii at Manoa, Honolulu, Hawaii (42)
**
2:00 p.m. Evaluation of garlic extract for control of com earworm, Helicoverpa zea, in sweet corn - Benoy
Fouche and Dawn Bninmeicr. University of California-Cooperative Extension, San Joaquin County. California (43)
2:15 p.m. Weed control with dimethenamid in onions growing on organic soils -LA, Ellerbrock and B. L
Phillips. Department of Fruit and Vegetable Science, Cornell University. Ithaca, New York (44)
m
2:30 p.m. The use of foliarly-applied nitrogen fertilizers for early-season weed control in onion seed crops Mike Murray, University of California-Cooperative Extension. Colusa County (45)
- Conference Center - Pavillion Room
Session 5: Crop Culture, Physiology, Growth, Storage - Conference Center - Room 302
3:15 p.m
Do onions have a critical plant size for bulb formation? - H.C. Wlen, B.S. Orenstein and L.A. Ellerbrock,
Department of Fruit and Vegetable Science, Cornell University. Ithaca, New York (46)
3:30 p.m.
Alternative onion transplant production in Colorado - Michael E. Bartolo and Frank C. Schweissing.
Colorado Stale University. Arkansas Valley Research Center, Rocky Ford. Colorado (47)
3:45 p.m.
Sudan grass rotation for improved yield and quality of onions produced on organic soils in New
York - John J. Mishancc. Cornell Cooperative Extension. 1PM Program. Voorheesville. New York (48)
4:00 p.m. Non-destructive measurement of quality parameters of stored onion - Zsuzsanna F0si8s, JAzsef
Fclfoldi, Sandor Istella, University of Horticulture and Food Industry, Posiharvest Department, Department of
Physics and Control and Department of Vegetable Growing, Budapest (49)
4:15 p.m. Long-term storage potential of garlic {Allium salivum L) with cryopreservation and regeneration
in tissue culture • Richard Hannan and Denise Garoutte, USDA. AM. Western Regional Plant Introduction
Station, Washington State University, Pullman, Washington (SO)
4:30 p.m.
U.S. Onion Market Dynamics - Wayne Mininger, National Onion Association
4:45 p.m.
Closing Remarks
5:00 p.m. Adjourn
National Onion Research Conference Tour
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7:30 a.m.
Board Bus at the Radisson Hotel
8:00 -10:00 a.m.
10:15 - 11:00 a.m.
Empire Research, Davis - Continental breakfast served
Center for Engineering Plants for Resistance Against Pathogens (CEPRAP)
11:15- 12:00 noon
12:30 p.m.
Vegetable Crops Field Research Facility, University of California, Davis
Lunch at Woodland Flyers Club hosted by Seminis Vegetable Seeds
2:00-3:00 p.m.
4:00 p.m.
Seminis Vegetable Seeds, Woodland
Arrive Radisson Hotel
Univeniiy orCatifoinia. Davit
Progrun P«ge 4
POSTER SESSION I
♦
Fall-planted onion variety trials at New Mexico State University - Christopher S. Cramer, Jose Luis Mcndoza
and Joe N. Corgan, Department or Agronomy and Horticulture, New Mexico Stale University, Las Cruces, New Mexico (I)
♦ Seed yield and morphology of CMS onion populations possessing the cytoplasm of A. galanthum •
Michael J. Havey, USDA-ARS, Department of Horticulture, University of Wisconsin-Madison, Wisconsin (2)
♦ The Vidalia onion industry: past, present, and future - George Boyhan, University of Georgia, East Georgia
Extension Center, Statesboro, Georgia (3)
♦ Onion and garlic research in India - U.S. Dalla, AS. Sidhu and S.S. Bal, Punjab Agricultural University, Punjab,
India (4)
♦ Onion growth and N uptake in southeastern Colorado • Ardell D. Hulvorson, Ronald F. Foiled, and Michael E.
Bartolo, USDA-ARS and Colorado Slate University, Fort Collins, Colorado (5)
♦ Irrigation scheduling to optimize yields and reduce leaching of nitrates for Maui sweet dry onions • Robin
S. Shimabuku and I-Pai Wu, Hawaii Cooperative Extension Service, University of Hawaii, Kahului, and Department of
Biosystcms Engineering, University of Hawaii at Manoa, Honolulu, Hawaii (6)
♦
Effects of Transplant Date and Transplant Size on Production, Quality, and Pungency of Sweet Onions •
Marita Camwell. Mark Gatkcll. Xunli Nie, Richard Smith. Ben Faber. and Ron Voss. University of California-Cooperative
Extension (7)
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POSTER SESSION II
♦ Synthetic garlic oil reduces viability ofSclerotium cepivontm sclerotia and incidence of white rot on
onions onions - MR McDonald and MHY Hovius, Univ. of Guelph, Muck Crops Research Station, Keltleby, Ontario,
Canada(8)
♦ Base temperature for garlic growth determinations in the white-garlic type - J. A. Puru-la. J L Burba and S.
Lanzavechia, Garlic Project, EEA La Consulta INTA, La Consulta, Mendoza. Argentina (9)
♦ Development of a bioassay to determine the presence of specified fungal pathogens of onion - Karen L.
Sirois. David P. LoParco, and James W. Lorbeer. Department of Plant Pathology. Cornell University, Ithaca, New York (10)
♦
1PM Pest Management Guidelines for Onion and Garlic • R. Voss. R Covicllo. W. Chancy. W Bentley. S. Orloff.
R.M. Davis. F. Laemmlen. C. Bell. H. Agamalian, D. Cudncy, B. Fischer. B. Westerdahl. U. Kodira, ML Flint, B.
Ohlendorf. University of California-Cooperative Extension, IPM Education and Publications (11)
<9>
Polymorphism in Allium species revealed by Simple Sequence Repeats - Ellen Pefliey. Anfii Hou, and
Laurence Trueman, Department of Plant and Soil Science, Texas Tech University. Lubbock, TX and Horticulture Research
International, Wcllsboume, Wanwick, CV (12)
Unimtily ofCtlifonii. Davis
Program Page 5
Session 1
Breeding and
Genetics
1998 National Onion Research Conference
History and pedigree of publicly-released onion germ plasm in the
United States during the 20th century
lI L. Goldman and 2MJ. Havey
'Department of Horticulture, University of Wisconsin-Madison
2USDA, ARS, Department of Horticulture, University of Wisconsin-Madison.
Most modern onion cultivars in the U.S. descend from a few open-pollinated populations
brought to this country by immigrants. For example, selection in the open-pollinated
populations Common Yellow and Silverskin by onion farmers in the eastern U.S. resulted
in the formation of Yellow Globe Danvers, which was a precursor to Early Yellow Globe
and Mountain Danvers. These populations, along with open-pollinaled populations such
as Red Wethersfleld, California Early Red, Early Grano, and Southport Red, White, and
Yellow Globe formed the foundation germplasm for the first public onion breeding
program, initiated in 1922 by HA Jones. Early inbreeding work by Jones and colleagues
resulted in the development and widespread adoption of an inbred-hybrid breeding
scheme for onion. This scheme relied on a hybrid seed production system that included
genes conditioning cyioplasmic male sterility and fertility restoration. Early breeding
efforts involved self-pollinating or sib-mating plants from open-pollinated populations
Jones's breeding program began, the first inbred lines and hybrid cultivars from this
program were released Additional state and federally supported onion breeding efforts
were initiated in California, Colorado, Idaho, Iowa, Louisiana, Texas, Michigan, New
Mexico, New York, Utah, and Wisconsin. Together with the US.DA. National Onion
Breeding Program in Maryland, more than 60 hybrid cultivars were released from 1952 1998. More than 130 inbred lines, many of them sterile and maintainer pairs, were
released by the public sector breeders during the same time period. This presentation will
trace the history and pedigree of public onion releases and public onion breeding
programs in the U.S. from the beginning of the 20th century to the present.
Page 1
r
Cytoplasms used commercially to produce hybrid-onion seed
Michael J Havey, USDA-ARS and Dep. of Horticulture
1575 Linden Dr.. University of Wisconsin, Madison, Wl 53706
Phone: 608-262-1830; Fax: 608-262-4743; Email: mjhavey@facstaff.wisc.edu.
Hybrid-onion (Allium cepa) seed is produced using male-sterility systems, including
asexual propagation of individual male-sterile plants and cytoplasmic-genic male sterility
(CMS). The principle source of CMS used in onion seed traces back to a single plant
identified in 1925 in Davis, CA. Other sources of male-sterility have been reported in
Europe, Japan, and India; however, the relationships among these male-sterility systems
is not clear. I undertook restriction-enzyme analyses of the organellar genomes of five
independent sources of onion CMS: S cytoplasm, T cytoplasm, and sterile cytoplasms
from the Japanese population Imai Wa-Se, the Dutch population Rijnsburger, and the
Indian population Nasik White. The chloroplast genome of S cytoplasm and the sterile
cytoplasms from Rijnsburger and Nasik White were identical for all evaluated
polymorphisms; a few putative mitochondrial polymorphisms may are' being re-
evaluated. Both T cytoplasm and the source of sterile cytoplasm from Imai Wa-Se appear
to be closely related. These results established that the same or very similar male-sterile
cytoplasms have been independently isolated.
Page 2
The USDA onion-breeding program: new releases and new directions
Michael J Havey, USDA-ARS and Dep of Horticulture
1S7S Linden Dr., University of Wisconsin, Madison, Wl S3706
The USDA has supported onion breeding since the 1930s. The program was initially
directed by Dr. Henry Jones and was located in Beltsville, Maryland. Since 1968, the
USDA onion breeding program has been located in Madison, Wisconsin. For over SO
years, the USDA program concentrated on the development of superior inbreds and
hybrids. Our commitment to the development of superior inbreds continues, although we
are spending little time on hybrid development. At the time of Dr C E Peterson's death,
there were many numbered inbreds from fertile-by-fertile crosses with little to no
pedigree information. Over the last 10 years, I have systematically evaluated the
combining ability, disease resistance, and phenotype of all inbreds assigned numbers by
the late Dr. Peterson. Almost all numbered inbreds were either poor combiners or
possessed some defect. Three inbreds of merit, were given out by Dr. Peterson before his
death and will be formally released. We continue to develop and evaluate inbred onion
populations, concentrating on red A/B pairs, Spanish * storage crosses, and populations
with low pungency and defined health benefits (in cooperation with 1. Goldman).
Synthetic populations from superiorly combining inbreds have been synthesized and are
being subjected to recurrent selection.
Page 3
Onion breeding for the dehydration industry in Argentina
Claudio R. Galmarini
E.E.A. La Consulia INTA, C.C. 8 (5567)
La Consulta, Mendoza, Argentina
and
Dep. of Horticulture
1575 Linden Dr., University of Wisconsin, Madison, Wl 53706
Phone: 608-262-4721; Fax: 608-262-4743; Email: crgalmar@students.wisc.edu
The onion crop has great importance in Argentina and is one of the main exponed fresh
vegetables. For decades there have been well established onion breeding programs,
developing short, intermediate and long-day cultivars. About 2% of the Argentine onion
crop is for the dehydration industry. There are 15 dehydration plants with activity
concentrated in the Cuyo region. About 40% of the dehydration products are exported,
mainly to Brazil. The dehydration industry uses open pollinated (OP) cultivars, mainly
Southport White Globe, Ancasti, and Blanca Chaia; all have high solids and white,
pungent bulbs. At the beginning of the 1990s, a special agreement between the
dehydration industry and the onion-breeding program of the La Consulta Experimental
Station of INTA was established. The goal is to develop OP onion cultivars and hybrids
of high-solids content. In the breeding program, mass selection, recurrent selection, and
hybrid production are used, together with in vitro culture techniques to propagate some
bulbs of high solid content. In 1997 REFINTA 20 was released by INTA. This new
cultivar originated from a selection of Southport White Globe, has white pungent bulbs,
and an average total solids content of 20 ± 1%. This is 3 % more than the starting
populations used by the industry (17 1 2%). The Argentine industry has exclusivity of
this cultivar for 20 years and has been registered with the Argentine seed-law system.
The breeding program continues to work towards the development of hybrids and
evaluation of micropropagated high-solids lines.
University or California, Davis
Page 4
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Screening of onions for ability to produce large, mild bulbs in New York
B L Phillips, L. A. Ellerbrock, and A. Pappas.
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'm
**
m
Department of Fruit and Vegetable Science, Cornell University, Ithaca, NY 14853
Phone: 607-255-6553; Fax: 607-255-0559; E-mail: Iae6@cornell.edu
During a period of three years, a large number of onion varieties and breeding lines were
evaluated for their ability to produce large(3-inch-minimum-diameter) bulbs with low
pugency and high soluble solids in New York State. Additionally, the effects of soil type,
drought stress, and time of harvest on bulb yield and pungency levels were measured.
Pungency was assessed by analyzing for enzymatically produced pyruvic acid, and, in
general, bulbs produced on organic soils were considerably more pungent that those
produced on mineral soils Drought stress, in some case, appeared to increase onion
pungency. Onion varieties that appear to offer the best potential for acceptable size,
pungency levels, and storage ability in New York include Candy, RNX 10081, RNX
10734, Viceroy, XPH 15040, Uni-Globe 108, Uni-Globe 118, and Boxster
Page S
Onion breeding research at New Mexico State University
Christopher S. Cramer, Marisa M. Wall and Joe N. Corgan
Department of Agronomy and Horticulture, New Mexico State University
MSC 3Q. Box 30003, Las Cruces, NM 88003-8003
Phone: 505-646-2657; Fax: 505-646-6041; E-mail: ccramer@nmsuvml.nmsu.edu
Over the past 20 years, the New Mexico State University Onion Breeding Program, led
by Dr. Joe Corgan, has developed and released 16 open-pollinated, short- and
intermediate-day onion varieties and breeding lines. The program also has investigated
interspecific hybridization, pink root resistance, bolting resistance, cold hardiness,
soluble solids, and pungency. Future directions of the program are release of adapted,
short- and intermediate-day, open-pollinated varieties and A, B, and C lines that possess a
variety of maturity dates, scale colors, soluble solids levels, and pungency levels. Lines
close to release include a fall-planted, short-day, open-pollinated line with a high
percentage of single centers, a fall-planted, intermediate-day, open-pollinated white line,
a spring-planted, late-maturing, open-pollinated white line, and spring-planted, yellow AB lines. Future research will be directed towards identifying genes associated with pink
root and Fusarium basal rot resistance, and further understanding of bolting, cold
hardiness, bulb quality traits, soluble solids, and pungency.
Page 6
Analyses of recombinant AUium cepa x A. fistulosum backcross
individuals
Anfu Hou, Ellen B Peffley
Texas Tech University, Department of Plant & Soil Science
Phone: 80-742-2637; Email: tpebp@ltacs.nu.edu
Interspecific hybridization has been used for the purpose of introducing desirable traits
from AUium fistulosum into A. cepa, however, onion cultivars possessing A. fistulosum
genes have not been released. A major barrier for successful introgression has been
sterility of Fi hybrids and derivatives. F|BC3 plants in this study were generated by
backcrossing A. cepa to A. cepa x A. fistulosum hybrids. Characters evaluated to track
introgression were bulb, foliage, and inflorescence morphology; isozymes, chromosome
karyotypes, and fluorescence in situ hybridization patterns. Overall, growth habit and
floral characters of the F1BC3 plants were much like A. cepa. Soluble solids and
pungency in FiBCj bulbs ranged from low as in A. cepa to high as in A. fistulosum. Bulbtype but recombinant onions with high soluble solids and low pungency were identified.
Fertile, A. cepa -like plants were recovered which had high pollen viability, set seeds, and
possessed A. fistulosum isozymes. Fluorescence in situ hybridization was done with
biotin-labeled genomic DNAs of both species. A highly repetitive 376 bp A. fistulosum
DNA sequence revealed telomeric hybridization sites; similar telomeric sites were
observed when hybridizing labeled A. fistulosum genomic DNA onto chromosomes of A.
fistulosum individuals and F|BCj plants.
Page 7
!
Estimation of quantitative trait loci controlling solid content, pungency,
and antiplatclet activity of onion (Allium cepa L.)
m
Claudio R. Galmarini, I. Goldman, and M. J. Havey
USDA-ARS and Dep. of Horticulture
1575 Linden Dr., University of Wisconsin, Madison, WI 53706
^
1
P
m
m
m
Phone; 608-262-1830; Fax: 608-262-4743
Email: mjhavey@facstaff.wisc.edu and ilgoldma@facstaffwisc.edu
A 138-point genetic map is being used to identify and estimate the magnitude of
quantitative trait loci controlling, solids content, pungency, and antiplatelet activity of
onion. Solid content is an important characteristic related to onion flavor, texture, and
storability and has practical importance for the dehydration industry. The antiplatelet
activity of onion may be beneficial to the human cardiovascular system. Pungency is an
important quality trail for fresh consumption.
Significant correlations have been
demonstrated between enzymatically produced pyruvic acid and sensory evaluations of
onion pungency. QTL controlling pungency, total solids, soluble solids, and antiplatelet
activity are being estimated over environments using 54 F3 families, derived from the
cross between Brigham Yellow Globe 15-23 (BYGI5-23) and Alisa Craig (AC43).
Maturity (days after planting to 50% collapsed foliage), storability, soluble solids, total
solids, pungency and antiplatelet activity are evaluated. This study should determine if
correlated traits are conditioned by the same chromosome regions and, over the long
term, if marker-facilitated selection can be used to develop value-added onion cultivars.
Page 8
1W8 National Onion Research Conference
RFLP and FISII analysis of advanced backcrosses of an Allium
interspecific hybrid {Allium cepa X Allium fistulosum) to Allium cepa
m
Eduardo Villanueva-Mosqueda and Michael J. Havey
m,
1575 Linden Dr, University of Wisconsin, Madison, WI 53706
Phone: 608-262-1830; Fax: 608-262-4743; Email: mjhavey@facstafr.wisc.edu.
pi
***
Onion (Allium cepa L.) is the most important species of the cultivated Alliums. Breeders
have attempted to incorporate quality and resistance traits from Allium fistulosum into the
onion genome. Although there are several reports of successful interspecific
hybridizations between A. cepa and A. fisiulosum, there has not been strong evidence of
recombination among the genomes.
After more than 50 years of interspecific
hybridizations and backcrossing to onion, no successful introgression has been
convincingly documented The objective of this study was to use FISH and RFLPs to
assess recombination between the genomes of A. cepa and A. fistulosum using BC
progenies in the normal male-fertile cytoplasm of A. cepa. Sequence divergence between
A. cepa and A. fisiulosum was sufficient to allow chromosomes to be distinguished by
GISH and revealed evidence for recombination among the genomes of A. cepa and A.
fistulosum. RFLP analysis demonstrated that advanced backcross populations possess the
normal male-fertile cytoplasm and the 45s ribosomal DNA of bulb onion.
Page 9
Molecular-facilitated selection of maintainer lines in onion
Ali Fuat Gokce and Michael J. Havey
Cytoplasmic-genic male sterility (CMS) is used to produce hybrid-onion seed. For the
most widely used source of CMS in onion, male sterility is conditioned by the interaction
of sterile (S) cytoplasm and the homozygous recessive genotype at a single nuclear malefertility restoration locus (Ms). Maintainer lines used to seed propagate male-sterile lines
possess normal fertile (N) cytoplasm and the homozyous recessive genotype at the Ms
locus. Presently, it takes four to eight years to establish if maintainer lines can be
extracted from an uncharacterized population or family. We previously developed a PCR
marker useful to distinguish N and S cytoplasms of onion. To tag the nuclear malefertility restoration locus (Ms), we evaluated segregation at Ms over at least three
environments. Segregations of AFLPs, RAPDs, and RFLPs revealed molecular markers
flanking the Ms locus at 1.9 and 7.1 cM. These organellar and nuclear markers are being
used to select plants from open-pollinated onion populations and determine the reduction
in testcrosses required to identify CMS-maintaining genotypes.
Pa8e
l'J98 National Onion Research Conference
Transformation of onion (Allium cepa L.)
Eady C.C, Weld R.J. and Lister C.E.
New Zealand Institute for Crop and Food Research Ltd.
Private Bag 4704, Christchurch, New Zealand
Phone: 64-3-32S-6400; Fax: 64-3-325-2074; Email: eadydgcropxrUz
An Agrobacterium tumefaciens - mediated transformation method has been developed for
onions (Allium cepa L.) Transgenic plants have been produced at a maximum
transformation frequency from immature embryos of 3.2 %. The method takes between
3-5 months from explant to primary regenerant entering the glasshouse. Multiple shoot
formation from primary transgenic material made possible the clonal multiplication of
these transformants. The T-DNA transferred to the plants contained the m-gfpS-ER
reporter gene and the nplll antibiotic resistance gene. Onion tissue expressing the m-gfp5ER gene was observed to fluoresce green when excited with blue light. Expression of
nptll in onion plants has conferred the ability to root ori medium containing high levels of
the antibiotic geneticin. The transgenic nature of individual plants was confirmed by
Southern blot analysis. Over 50 transgenic plants, from 14 independent transformation
events, have been produced in three experiments. We believe this to be the first routine
onion transformation protocol.
Pa6c ' 1
Direct somatic orgnnogenesis induced on mature onion ovaries or
flowers
Borut Bohanec, Zlata Luthar
University of Ljubljana, Biotechnical Faculty, Centre for Plant Biotechnology and
Breeding, Jamnikarjeva 101, 1000 Ljubljana, Slovenia.
Phone: 386-61-123-11-61; email: borut.bohanec@uni-lj.si
Despite several attempts a repeatable genetic transformation procedure was not yet
reported in onion. In most species, usually a key factor needed for a successful
transformation protocol was the establishment of a tissue culture protocol producing high
frequency regeneration via organogenesis or embryogenesis. Such regeneration
procedure would be also appropriate for micropropagation especially if callus formation
can be excluded. During last two years in our laboratory a series of experiments were
conducted to assess optimal in vitro protocols needed to achieve direct somatic
organogenesis in onion. Studies, focused on a two step induction/regeneration procedure
included variation in choice of organs, duration of induction period, choice or plant
growth regulators used in both stages, macro and micro elements mixtures, content and
choice of carbohydrates, gelling agents, light conditions, organ extraction protocols and
effects of genotypes. As result of these studies a highly repeatable protocol was
optimized resulting in a high frequency induction of direct somatic organogenesis.
Complete flower buds and especially isolated ovaries were found highly responsive
producing organogenic (embryogenic) structures without any callus formation. Such
organogenic structures (at this stage ideal for transformation events) later form multiple
shoots, which can be grown to adult plants via standard micropropagation procedures. At
present, protocols are available for an efficient micropropagation procedure resulting
with several thousand of clones per donor plant, while transformation protocols, using
biolistic and Agrobaciehum approach is in process.
University of California. Davis
Page 12
I-198 National Onion Research Conference
Molecular analysis of cytoplasmic diversity in leek
Daniela Lopez Leite and Michael J. Havey
1575 Linden Dr, University of Wisconsin, Madison, WI 53706
Phone: 608-262-1830; Fax: 608-262-4743; Email: mjhavey@facstafr.wisc.edu
Hybrid leek (Allium ampeloprasum L. war.-porrum) is more uniform and higher yielding
than open-pollinated cultivars. Leek has perfect flowers and a male-sterility system is
required to produce hybrid seed. A genie male-sterile plant has been identified and
asexually propagated as the female parent of leek hybrids. A system of cytoplasmic male
sterility (CMS) in leek would be a cheaper alternative to the high cost of asexually
propagating female plants for hybrid production. CMS systems are used to produce
hybrid bulb onion, bunching onion, and chive, but no CMS system has been identified in
leek.
Restriction fragment length polymorphisms (RFLPs) in the chloroplast and
mitochondrial genome have correlated with CMS in many crops. We undertook gel-blot
analyses of the chloroplast and mitochondrial DNAs to identify polymorphisms among
the organellar genomes of 60 accessions of cultivated A. ampeloprasum
No
polymorphisms were detected in the chloroplast genome of leek and kurrat
Three
accessions of leek and one of kurrat possessed polymorphisms for seven mitochondrial
probe-enzyme combinations. Great-headed garlic differed from leek and kurrat for six
polymorphisms in the chloroplast genome and for many mitochondrial probe-enzyme
combinations.
We identified individual leek plants possessing mitochondrial
polymorphisms and are presently establishing if polymorphic cytoplasms correlate with
the expression of CMS.
GJfr*VU\*s—'
University or California. Davis
Page 13
First report on storage longevity and genetic, diversity of the USDA
garlic (A. sativum) collection
m>
m
Richard Hannan and Barbara Hellier
USDA, ARS, Western Regional Plant Introduction Station
59 Johnson Hall, WSU, Pullman, WA
Phone: 509-335-1502; Fax: 509-335-6654; E-mail: hannan@wsiinixwsu.edu
The USDA, ARS, NPGS maintains the garlic collection at the Western Regional Plant
Introduction Station, Pullman, WA. The collection currently numbers 213 accessions.
The garlic germplasm is grown each year in field plots in order to provide material for
regeneration and for distribution. Following harvest, curing and cleaning, the garlic is
stored at 13-15T and 55% RH as intact bulbs. A common interest and concern with
garlic is the longevity of each clone in storage. A study on 177 accessions was conducted
I
to detennine how long each accession could be maintained under our storage conditions.
rm
Three representative bulbs per accession were selected and numbered. Readings were
taken on bulb firmness (scale 1-5 where l=soft and 5=vcry firm) and sprouting (visible
shoots=sprouted) every 30 days for 12 months. The accessions were considered culls
when they had sprouted and/or turned soft (firmness<3). Results indicated a wide range
of diversity in the storage life of the PI garlic germplasm. Some genotypes sprouted as
early as 90 days after harvest, while others remained dormant and firm for over 12
months. Approximately half of the accessions had sprouted by the end of March. After
that, those that had not sprouted, slowly desiccated. After 12 months in storage 8% of the
accessions were still firm, not sprouted and not desiccated
Page 14
I9'J8 National Onion Research Conference
Genetic diversity in garlic (Allium sativum L.) as assessed by amplifled
fragment length polymorphism (AFLP)
m
m
m
wn
m
•pn
Meryem Ipek & Philipp W. Simon
USDA-Agricultural Research Service, Vegetable Crops, University of Wisconsin
Department of Horticulture, 1575 Linden Drive, Madison, WI 53706
Phone: 608-262-1248; Fax: 608-262-4743;
Email: psimon@facstaff.wisc.edu psimon@facstarT.wisc.edu
Garlic (Allium salivum L), an asexually propagated crop known for at least 5000 years,
displays great morphological diversity. The genetic diversity of 53 garlic clones and
three A longicuspis clones, the proposed progenitor of A. salivum, was evaluated using
AFLP. Three primer combinations of EcoR I + 4 - Mse I + 3 (where + 4 and + 3 are the
number of selective bases used for the corresponding primer) generated a total of 183
polymorphic fragments. The Jaccard's similarity matrix was used for UPGMA cluster
and principle component analyses. The results of cluster analysis were compared with
morphological characters and isozyme groupings of Pooler and Simon (1993). Although
similarities between the clusters were low (( 0.30), some clones within the clusters were
very similar (0.95). Furthermore, 18 clones represented only six different types, within
which they shared 100% polymorphic AFLPs. These may, therefore, be duplicates. In
agreement with the results of other investigators, A. longicuspis and A. sativum clones
were clustered together with no clear separation, suggesting these species are not
genetically distinct. Since AFLPs are abundant, this technique can be another tool for
detailed assessment of genetic relationships in garlic.
Page 15
Microprojectile bombardment of garlic, Allium sativum L.
m
J Michele Myers and Philipp W Simon
USDA-Agricultural Research Service, Vegetable Crops, University of Wisconsin,
Department of Horticulture, 1575 Linden Drive, Madison, WI 53706
Phone: 608-262-1248, Fax: 608-262-4743; E-mail: psimon@facstafT.wisc.edu
We have successfully transferred and expressed the reporter gene p-glucuronidase (GUS)
m
and the selectable marker neomycin phosphotransferase (NPT II) gene into the garlic,
Allium sativum L.
The clone 'RAL27' was transformed using microprojectile
bombardment as the method of gene delivery. Cell suspensions derived from callus
produced on root tissue were bombarded with 1.6 micron gold particles coated with
pBI121. The GUS gene was under the control of the CaMV35S promoter white the NPT
II gene was under the control of the nopaline synthase promoter (nos). GUS assays were
""
performed 2 days post bombardment to confirm positive initial transformation events.
Selection of putative transformants occurred on medium supplemented with parmomycin
sulfate (100 mg L1) and solidified with 0.35% low gelling temperature agarose. After 14
m
m
to 16 weeks on selection medium, regenerated shoots were observed on several calli.
Incorporation of foreign genes into the genome of sixteen-month-old transgenic plants
was confirmed by PCR with specific primers for GUS and NPT II and Southern blot
analysis. GUS assays of sixteen-month-old confirmed transformed plants revealed no
GUS activity.
Page 16
Session 2
Seed
Production
'J'Jg National Onion Research Conference
The effects of hybrid onion floral characteristics on honey bee activity
Bill B. Dean and Erin M. Silva
p*
Washington State University, Department of Horticulture and Landscape Architecture
24106 N. Bunn Rd, Prosser, WA 99350
Phone; (509) 786-9260; FAX: (509) 786-9370; email: silva(g!wsunix-wsu.edu
Poor hybrid onion seed yields due to lack of pollination by the honey bee continues to be
a major problem in Washington's Columbia Basin region. This study examined onion
m
floral characteristics and honey bee activity.
concentration, and sugar quantity.
!""
i
rwi
Nine, hybrid onion parents differing in
relative bee attractiveness were grown in replicated 2.4m X 4-9m field plots. Nectar
samples were collected from the flowers to determine total nectar volume, sugar
Volatile floral odor samples were collected using
headspace analysis techniques and analyzed by GC/NIS to determine qualitative and
quantitative differences in odor profiles and their effect on bee attractiveness. Hybrid
onion fields in Washington, Oregon, and Idaho also were analyzed to determine the
effects on nectar production, odor production, and competitive crops on relative bee
activity and final seed yield. Variation was observed in nectar production and odor
production between the more and less attractive hybrid parents. When presented with an
alternative crop, honey bees ignored the onion seed crop in favor of other food sources.
Onion floral volatiles were found to be composed of predominantly sulfur compounds,
with the more, attractive hybrid parents emitting a greater quantity of total volatiles.
Page 17
Onion seed production in the lower Sacramento Valley
Ron Voss1 and Mike Murray2
University of California
'Vegetable Crops Department
One Shields Avenue, Davis, C A 95616
Phone: 530-752-1249; Fax: 530-752-9659; E-mail: revoss@ucdavis.edu
2Colusa County CE, P.O. Box 180, Colusa, CA 95932
Phone: 530-458-0577; Fax: 530-459-4625; E-mail: mmurray@ucdavis.edu
Limited acreages of direct-seeded onion seed crops have been grown in the lower
Sacramento Valley for many years. Recently, the acreage of commercial hybrid seed
production has expanded The crops are planted from August through September and
harvested the following July through August. Important production challenges include
weed and disease management. The crop is hand-harvested, dried on tarps exposed to the
sun and threshed in the field before delivery to the seed contractor. This presentation will
identify and discuss the major production and harvest issues encountered in the region.
Page 18
Effect of harvest practices on seed quality of three onion hybrid
varieties
Ron Voss1, Mike Murray2, Kent Bradford1, Herb Phillips1, Jim Thompson3
University of California
'Vegetable Crops Department, and Agricultural and 'Biological Engineering Department
One Shields Avenue, Davis, CA 95616
2Colusa County CE, P.O. Box 180, Colusa, CA 95932
Phone: 530-752-1249; Fax: 530-752-9659; E-mail: revoss@ucdavis.edu
The Sacramento Valley is an important seed production area for intermediate and long
day hybrid onion cultivars. Onion seed stalks and umbels are typically harvested by hand
in mid-summer, air-dried in the sun on canvas tarps, and threshed, before delivery to the
contracting seed company.
Some cultivars have borderline, or below, acceptable
germination (e.g. 85%)
The objective was to determine how seed quality (e.g.
germination, vigor, size/weight) can be affected by harvest related practices.
An
experiment was conducted with variable harvest (i.e. cutting) dates, forced vs. air drying,
and sun exposed vs. shading. Samples were also collected at various locations in the
harvest process and in the drying piles. Temperature within the piles was monitored.
Three cultivars were used - Linda Vista, Cougar and Mercedes. Hand and machine
threshed samples were collected. Standard germination/vigor tests were conducted by
California Crop Improvement Association. The results of the trial will be discussed and
recommendations for further research or changes in practices will be presented.
Page 19
Session 3
Flavor,
Human Health
and Nutrition
A review of the regulation of sulfur metabolism and its effect on quality
in onions and garlic
Jane E. Lancaster, Martin L. Shaw, Meeghan D. Pither, Julie P. Farrant and John A.
McCallum
New Zealand Institute for Crop and Food Research
Private Bag 4704, Christchurch
New Zealand
Phone: 643-325-6400; Fax: 643-325-2074; Email: lancasterjVScrop.cri.nz
A distinguishing feature of the 500 or so Allium species is the metabolic network of
sulfur compounds resulting from the high sulfur content in these species. Sulfur nutrition
affects the flavor quality of onions and garlic and has been shown to affect the storage
quality of onions. Recent literature on the uptake, reduction and assimilation of sulfur
will be discussed particularly in relation to differences in sulfur metabolism between
onions and garlic. The effect of sulfur nutrition on the expression of the flavor enzyme
alliinase will be discussed. It is concluded that sulfur uptake from a given medium is
similar for both onion and garlic but differences in metabolism within the plants lead to
differences in quality characteristics.
Page 20
1998 Nalional Onion Research Conference
Nitrogen and its interaction with sulfur will affect onion flavors
William M. Randle
Department of Horticulture, University of Georgia, Athens, GA 30602-7273
While much of our previous work focused on the effect of sulfur (S) and flavor
development, empirical observations of field-grown onions hinted that the level of
applied nitrogen (N) could affect flavor intensity. In response, we conducted a series of
experiments to: 1) determine the effect of increasing N levels on onion flavors and, 2)
determine the interaction of N and S levels on onion flavors. Each experiment was
conducted in the greenhouse using nutrient solutions. Increasing N availability increased
bulb pungency except the highest N level. Total flavor precursor content (ACSO)
increased as N increased, but the ratio of the individual precursors changed. High N
favored methyl cysteine sulfoxide and propyl cysteine sulfoxide accumulation, but
decreased l-propenyl cysteine sulfoxide. Bulb firmness decreased as N increased. There
was a significant interaction of N and S fertility on bulb pungency and ACSO content.
When N levels were very low, bulb pungency was high regardless of the S level. With
high S, increasing N generally decreased pungency. Increasing S increased ACSO
content at all N levels. Increasing N generally increased ACSO content at all S levels.
Therefore, N and S fertility need to be considered when growing onions for flavor
intensities.
Page 21
Probing further into the nature of onion flavor development during
storage
David E. Kopsell and William M Randle
University Of Georgia, Department Of Horticulture, 1111 Plant Sciences Building
Athens, GA 30602
Phone: 706-542-2471, Fax: 706-542-0624; E-mail: davekops@archev uga.edu
In previously reported studies, the enzymatically formed pyrulvic acid (EPY) and Salk(en)yl cysteine sulfoxide (ACSO) levels were examined during cold temperature
storage. In these experiments, ACSO changes during storage could not explain EPY
behavior. Investigation has been conducted into the enzymatic reaction components in
order to understand how onion flavor is changing. Three SD cultivars were greenhouse
grown in artificial media and stored under two separate conditions, 3°C, 70% RH and
ambient room temperature (RT). Experimental data was taken on EFY, ACSO levels,
cellular pH, thiosulfinale, production, alliinase activity, alliinase time-course hydrolysis
of ACSOS, and bulb dormancy characteristics. EPY for 'Granex 33' and 'Dehydrator #3'
followed previously reported trends, while 'Evita' EPY increased slightly.
The
umoles/ml (Z.E)-propanethiol S-oxide, the lachrymatory factor (LF), for 'Granex 33' and
'Evita1 increased, while the LF for 'Dehydrator #3" decreased. EPY for RT storage was
lower than cold storage for the cultivars. Background cellular pH increased for each
cultivar during cold storage and was higher than RT pH. Onion flavor development
during storage is much more complex that previously thought, requiring the use of many
combined analyses to fully explain.
Page 22
IW8 Nalional Onion Research Conference
Juice extraction methods make difference in pungency estimation of
onion
Brian K Hamilton, Kil Sun Yoo, and Leonard M. Pike
Vegetable Improvement Center, Department of Horticultural Sciences
Texas A&M University, College Station, TX 77843
Phone: 409-862-4951; Fax: 409-862-4522, E-mail: bhamilto@taexgw.tamu.edu
Onion pungency has been widely estimated by measuring pyruvic acid content in
extracted onion juice. The original method by Schwimmer and Weston (SW) used
diluted juice from homogenated onion tissue with water. The SW method was slow and
several modifications were developed to speed up sample preparation time, such as
extracting juice by pressing, maceration of tissue in a plastic bag, or homogenization of
tissue without water.
We compared these four methods and found considerable
difference in the pyruvic acid content due to how the samples were processed. Since
every analysis laboratory adopts a different extraction method and this may cause varying
results of pungency estimation, we would like to suggest that a common method be
established for measuring onion pungency throughout the industry.
Page 23
Considerations for implementing pungency field testing and its
practical implications
William M. Randle, D.E. Kopscll, DA. Kopsell
Department of Horticulture, University of Georgia, Athens, GA 30602-7273
Onions can be marketed for specific purposes; some are intended to be eaten raw, others
are intended for cooking, while others may be used in the dehydrated state. However,
onion flavor intensity can vary dramatically within these categories. To better inform
consumers of the flavor intensity they might be purchasing, field sampling and pungency
testing can be used. Initiating a successful testing program requires several procedures to
be implemented. First, a valid pungency testing method must be used which represents
established sensory experiences with the chemical analysis. Second, because flavor
gradients exist within the bulb, tissue taken for analysis must represent the overall bulb
pungency. And third, a statistically valid sampling procedure must be ascertained for
production areas based on environmental conditions and varietal usage. If a field is
properly tested, a pungency mean and standard deviation can be determined. These
values can then be used to place onions in pungency categories, and the consumer will be
better informed. At the farm level, pungency patterns can be determined by coupling
field sampling with global position satellite systems. Precision farming techniques can
be then be employed to improve flavor quality and consistency.
Page 24
Development of an automated system for pyruvic acid analysis
Kit Sun Yoo and Leonard M. Pike
Vegetable Improvement Center, Department of Horticultural Sciences
Texas A&M University, College Station, TX 77843
An automated system for pyruvic acid analysis was developed in order to screen a large
number of onion bulbs in our breeding program. The system includes two HPLC pumps,
an autosampler with a S
micro liter loop, a column heater set to 70°C, a
spectrophotometric detector set to 485 nm, and an integrator or data collection computer.
Each pump delivers 0.7 ml dinitro phenyl hydrazine (DNPH) or 1.4 ml NaOH per
minute. Micro filtered onion juice is injected by an autosampler, mixed with DNPH
solution, and reacted in the column heater. The NaOH solution is mixed at the end of the
heater and absorbency at 485 nm was measured.
Peak area of each sample was
calculated into amount of pyruvic acid by using a standard curve. This new method can
eliminate human error, has high repeatability, and can run a sample per minute
Page 25
I
:
A comparison of onion-induced platelet aggregation by plasma and
wholeblood aggregometry
K. S. Orvis, C. R. Galmarini, I. L. Goldman and M. J. Havey
University of Wisconsin-Madison, 1575 Linden Dr., Madison, Wl 53706.
Fax: 608-2624743;
Email: kshousem@students.wisc.edu or crgalmar@students.wisc.edu
Onions posess a unique in vitro antiplatelet effect. This property has been implicated in
the prevention of cardiovascular disease, the leading cause of death in the United States
today. Previous investigation of this trait in onion has been by plasma aggregometry. In
this method, platelet rich plasma is isolated from human volunteers and mixed with onion
extract and platelet agonist. An alternative method that is quicker, less complicated and
may have more biological relevance, measures platelet aggregation in whole blood. A
set of experiments was conducted to compare onion-induced aggregation in both plasma
and whole blood. Two agonists, ADP and collagen, as well as several different onion
germplasm accessions were compared in replicated trials in both systems.
In these
experiments, ADP proved to be more effective than collagen in plasma aggregometry,
while collagen was more potent than ADP in whole blood aggregometry.
Preliminary
data indicate a positive correlation between the two systems. Ranking of antiplatelet
activity strength across germplasm accessions was preserved across systems.
Data
demonstrate that future investigation of onion-induced antiplatelet activity may utilize
whole blood aggregometry, a reliable, quick technique applicable to a breeding program.
Page 26
I 'J98 National Onion Research Conference
The forms of selenium delivered by onions to human diets
^
Dean A. Kopsell and William M. Randle
University of Georgia, Department of Horticulture, 1111 Plant Sciences Building
Athens, GA 30602
Phone: 706-542-2471; Fax: 706-542-0624; E-mail: deankops@arches.uga.edu
M
Selenium has long been established as an essential trace element in mammalian health.
Research has shown both Se deficiency and toxicity to be very real concerns. The health
benefits of immune system enhancement, cancer suppression, and cardiovascular disease
reduction are all associated with increased dietary Se. Because of its unique metabolism,
fOT,
the form of Se ingested becomes vital to its medicinal attributes. Onions and garlic were
revealed to be excellent delivery sources of organic forms of Se in human diets.
Selenium can exist in plants as seleno-proteins, seleno-amino acids, or as inorganic Se.
m
The form of Se ingested will determine if it is metabolized safely, or accumulated to
potentially harmful levels Onion tissues grown in the presence of selenate were found to
contain mostly water-soluble forms of Se. Protein and amino acid fractions made up
significant portions of the water-extractable Se. The level of Se in lipid fractions was
i™*
minimal. Levels of insoluble, or tightly held Se were also identified. The form of Se
delivered by plants is much more effective than traditional Se supplementation. If Allium
species are used to deliver Se to human diets knowledge of the form of Se existing in the
plant is vital to its application as a beneficial source of Se.
Page 27
Designing the ultimate onion for human health
Leonard Pike, Kil Sun Yoo, Roger Horn, and Carmen Lander
In the early days of mankind, the first humans relied on food plants to provide their very
existence. They soon found that certain plants had medicinal properties and consumed
them to prevent and cure illness. As medical technology advanced, physicians began
treating diseases with drugs and surgery. Within the last ten years, the philosophy of
preventing disease is returning to choosing health giving foods especially vegetables and
fruits. Until recently there has been limited emphasis placed on improving health
benefits offered by some vegetables. This has been attempted by breeding for increased
levels of certain compounds that were identified as being important to good health, such
as quercetin in onions
Garlic, onions, and peppers have long been thought of as
healthful foods and are considered to have properties that can prevent various diseases.
More recently cabbage, broccoli, cauliflower (and other cruciferous crops), potatoes,
melons and cucumbers have been listed by medical scientists as having possible effects
against cancer. Medical scientists are now aggressively exploring plant chemistry to
determine which natural occurring compounds provide specific protection against
diseases such as cancer, heart disease, diabetes, and others diseases. These research
efforts provide plant breeders with credible information to justify developing new
cultivars with uniform, higher levels of the health-providing compounds. One of the top
priorities the Vegetable Improvement Center is to work with medical scientist at M.D.
Anderson Cancer Center and Baylor College of Dentistry. Considering documented
results from these two prestigious institutions, plant breeders at Texas A&M University
have established vegetable breeding programs to develop designer vegetables for
improved health. At present, we have set specific objectives to improve onions, for
flavor, appearance and to contain uniform high levels of certain aniioxidants and other
phytochemicals that offer protection against various human diseases.
Emphases on
onions include work on organo-sulfur compounds and quercetin.
Page 28
Opportunities to market garlic based on health outcomes:
alliin, a cholesterol-lowering compound
m
Sterling, S.J andEagling, DR.
Institute for Horticultural Development (Agriculture Victoria)
621 Burwood Hwy. Knoxfield, Victoria 3176 Australia
^
Phone:+61 3 9210 9222
Fax: +61 3 9800 3521
sterlings@knoxy.agvic.gov.au
i"t
""*
Alliin, the main cysteine sulfoxide found in garlic, is similar in structure to the cysteine
sulfoxides in onions. Like quercetin (a flavonol found in onions), alliin has been shown
to have a range of medical benefits including the reduction of blood cholesterol, and for
this reason, alliin is of interest to the pharmaceutical industry. Research was conducted
at sites along the eastern seaboard of Australia and results showed that garlic grown in
this area contains levels of alliin up to 20 mg/g by fresh weight, the highest level so far
recorded world-wide. Further trials have shown that it is possible to consistently achieve
the level of alliin required for pharmaceutical processing (4 Smg/g FW or higher) over a
wide range of Australian climates, dependent on varietal needs.
Page 29
Session 4
Pest
Management
Summary of white rot research presented at the 2
Int. Symposium on
Edible Alliaceae (1997, Australia), and at the 6th Int. Workshop on
Allium White Rot (1998, Mexico)
Fred Crowe
Central Oregon Agr. Res. Center, Oregon State University
m
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850 NW Dogwood Ln., Madras OR 97741.
Phone: 541-475-7107; Fax: 541-475-6390; E-mail: fred.crowe@orsi.edu
Mary Ruth McDonald
University of Guelph, Muck Crops Research Station
1125 Woodchoppers Ln., RR01., Kettleby, Ontario LOG I JO
Phone: 905-775-3783; Fax: 905-775-4546; E-mail: mrmcdona@uoguelph.ca
F*1
fa™1
White rot disease of Alliums, incited by Sclerotium cepivorum, permanently infests field
soil. Traditional means of disease control have proven insufficient in cool season
production where environment favors activity of S. cepivomm
As a result, white rot
already has greatly reduced or now threatens sustained commercial production of Allium
crops in many parts of the world. White rot research has been and continues to be well
distributed worldwide, with limited contact among researchers in many countries.
A
summary of research reports from two recent international conferences will be presented.
^
While white rot remains difficult to control with single methods, many who work with
this disease now believe control may be possible with integrated methods.
Page 30
Screening onion lines for resistance to white rot (Sclerotium cepivorum)
and onion maggot fly (Delia antiqua).
Hovius MHY, MR McDonald, S Janse and K Vander Kooi
Muck Crops Research Station,
University for Guelph, 1125 Woodchoppers Lane, Kettleby, ON, LOG 1J0
Phone: 905-775-3783; Fax: 905-775-4546; E-mail: mhoviustgiuoguelph ca
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White rot of onions, a threat to the onion industry world wide, is a major limiting
factor in the production of onions in the Holland Marsh and surrounding areas in Ontario,
Canada. Resistance to registered insecticides has created a.need for new control methods
for the onion maggot fly. White rot, caused by Sclerotium cepivorum and the onion
maggot (Delia antiqua) are specific pests only of Allium species. Work by Esler and
Coley-Smith (1983) suggested that the mechanism which initiates the germination of
white rot sclerotia is linked to onion thiols and phenols and that those same chemicals
attract onion maggot flies to the plants. Gabelman (1991) also suggested that there may
be a positive relationship between white rot incidence and maggot fly damage in onions.
m
Onion breeding lines obtained from Dr. 1. Goldman, University of Wisconsin, Dr Rob
rm
Maxwell, Petoseed, Payette, Idaho and Asgrow Ltd in 1996 and 1997 were evaluated for
white rot resistance in infected commercial field sites. Onions were assessed for visible
white rot incidence at harvest maturity. Seeded and transplant trials were conducted to
evaluate plant resistance to onion maggot at the Muck Crops Research Station where
onion maggot flies occurred naturally. Maggot fly damage assessments began one week
after the peaks of the 1* and 2nd generations and at harvest. In 1996 and 1997 significant
w
I
m
mi
(P=0.05) differences in white rot incidence among breeding lines were found. Significant
differences in onion maggot damage and yield were found among the onion lines in both
years.
Significant (P=005) and positive Pearson and Spearman Rank correlations
(r=0 55 to 0.71) were found between white rot incidence and maggot fly damage
assessments at different intervals during the growing season. Total maggot fly damage
was correlated (Pearson) with white rot incidence at 2 out of 3 sites in I99S only In
1996, a significant but negative Pearson correlation (r=0.49) was found between white rot
incidence and maggot fly damage at harvest. Though we were unable to identify a
consistent link between resistance to onion white rot and resistance to the onion maggot
fly, the results from the Pearson correlation suggest that a tenuous relationship may exist.
This relationship requires further investigation.
References
I.
na*
Ester G and JR. Coley-Smith, 1983
Flavour and odour characteristics of species of
Allium in
relation to their capacity to stimulate germination of sclerotia of Sclerotium cepivorum.
Plant Pathology. 32:13-22.
™,
2. Gabelman WH. 1991
White rot and onion maggot.
Onion Research Conference., Savannah, GA: 147-151.
Proceedings of the National
Page 31
National Onion Research Conference
An analysis of the growth and reproduction of Sclerotium cepivorum on
Alliunt crops in relation to traditional fungicide use and white rot
incidence
Fred Crowe
Central Oregon Agr Res. Center
Oregon State University, 8S0 NW Dogwood Ln , Madras OR
Phone: 541 -475-7107; Fax 541 -475-6390; E-mail fred.crowefjBorst edu
Essentially all sclerotia of S. cepivorum eventually germinate in the presence of onion
and garlic roots in cool soils. Reproduction in roots is slight. Thus, nearly all sclerotia
present after an incidence of white rot are newly formed on decayed bulbs. Fungicides,
traditionally applied as seed treatments or in-furrow treatments at planting time, can
directly reduce the current season incidence of white rot, but frequently fail to reduce the
post-harvest inoculum density compared to the pre-plant inoculum density
Theoretically, superior fungicides which suppress bulb infection season long would
greatly reduce resultant inoculum density, and their continued use could achieve neareradication of sclerotia. However, fungicides which fail to suppress bulb infection season
long may result in increased inoculum density, with even poorer control in subsequent
crops. This is because S. cepivorum continues to spread up and down the planted row on
root systems below the zone of traditional fungicide application. If fungicides degrade
prior to harvest, S. cepivorum then moves up the now-unprotected roots to decay bulbs at
a later stage of bulb development, when the food base for fungal reproduction is greatest.
Traditionally-applied fungicides, then, must be very effective against S. cepivorum, they
must last for the full season, and they must do so dependably. Deeper placement of less-
than-superior fungicides through the zone where root density is highest should reduce
plant-to-plant spread, late season plant loss and late season fungal reproduction.
Page 32
Present status of bacterial diseases of onion and their control in New
York
James W. Lorbeer and Norman A. Gundersheim
Department of Plant Pathology
Cornell University
f«
Ithaca, NY 14853
Phone: 607-255-7875; Fax: 607-255-4471; Email: jwl5@cornell.edu
m
New York onion growers. Bacterial bulb decay has approached 35 % in some storages.
jm
F*i
In recent years bacterial diseases of onion have increased in their economic importance to
Research conducted during 1996-98 indicated when onions are topped only after the
necks are dry, this form of bacterial decay can be reduced. Undercutting (all roots
severed) and windrowing onions until the inside neck tissue is completely dry prior to
harvest and topping should greatly enhance this method of control. Although application
of copper fungicides has indicated bacterial decay control in some experiments,
interpretation of the results must account for the relative succulence of neck tissue at
harvest. If the fungicide did not adequately control onion leaf diseases, the bacterial
decay levels most likely were regulated to a great extent by the level of neck succulence
at harvest. Recent research has indicated that water in drainage ditches and slow moving
streams is a source of bacteria which blight onion plants and decay onion bulbs. During
1997 Burholderia cepacia was implicated as a cause of bacterial canker of onion plants.
Envinia chiysanlkemi was proven to be the cause of a serious onion plant and bulb
disease during 1995.
Page 33
Onion bacterial disease management in Colorado
Howard F. Schwartz and Kristen J. Otto
Colorado State University, Dept. of Bioagr. Sci. & Pest Mgmt
Fort Collins, CO 80523-1177
Phone: 970-491-6987; Fax: 970-491-3862; E-mail: hfspp@lamar.colostate.edu
Portions of the Colorado onion-growing region have dealt with a complex of bacterial
diseases including Bacterial Soft Rot, Pantoea Blight, Sour/Slippery Skin and
Xanthomonas Leaf Blight during the 1996 to 1998 growing seasons. Disease loss
severities have varied in relation to adverse weather associated with rain and storm
patterns. Disease management efforts have been enhanced by recent laboratory and field
work with copper-based bactericides tank-mixed with EBDC fungicides. Results of these
studies will be discussed in relation to an integrated pest management strategy for
bacterial, diseases of onions in Colorado.
Page 34
Evaluation of fungicides and priming of seed for the control of onion
smut, Urocystis cepulae Frost, on onions
MR McDonald, S. Janse and K Van der Kooi,
Univ. of Guelph, Muck Crops Research Station
Ketlleby, Ont. Canada
Phone: 905-775-3783; Fax: 905-775-4546;
E-mail: pirmcdona@uoguelph.ca. siansc@uoinieiph.ca. kvander@uo«ielph.ca
Onion smut is endemic in the organic soils of the Holland/Bradford Marsh area of
Ontario, Canada. If emerging onion seedlings are not protected by ftmgicide, levels of
smut infection range from 40 to over 90%. Currently, the seed treatment PRO GRO (30%
carbathiin and 50% thiram) is the only fungicide registered for use on onions in Ontario.
Field trials were conducted to determine if other fungicides or the use of primed seed
would improve the control of onion smut. Evaluations of primed and unprimed seed from
the same seed lot of onion cv's Quantum, Tornado and Hustler (1997) and Tribute,
Festival and Copra (1998) failed to show any reduction in incidence of smut. Seed
treatments Dividend (32.8% difenoconazole) and Raxil (8% tebuconazole) did not
control onion smut, while Dithane DG (75% mancozeb) and Vitavax (97% carbathiin) in
the seed furrow were effective. There is still a need for improved treatments to control
onion smut under conditions favorable for disease development.
Page 35
Synthetic germination stimulants decrease incidence of smut {Urocystis
cepulae Frost) on onions
MR McDonald and MHY Hovius
Univ. of Guelph, Muck Crops Research Station
Kettleby, Ont. Canada
Phone: 905-775-3783; Fax: 905-775-4546;
E-mail: mrmcdona@uoguelph.ca,mhovius@uoguelph.ca
Trials were conducted in the greenhouse and in a commercial field to determine if
products which stimulant the germination of smut teliospores would reduce the incidence
of onion smut. For the greenhouse trial, naturally infested organic soil was collected
from the field and mixed with either of the synthetic germination stimulants diallyl
disulfide (DADS, at a rate of 1 ml/m2 in 50 ml of water ) or n-propyl disulfide (DPDS, at
1 or 2 ml/m2 in 50 ml water),obtained from United -Agri-Products. Treated soil was
stored for three months then seeded with onion cvs. Taurus and Fortress. Onions, cv.
Tribute, were seeded in 1998 in a field that had been treated with DADS(10 L/ha) in the
fall of 1996 and 1997. Onions were assessed at the first and third true leaf and at harvest.
In the greenhouse trial, DADS and DPDS at 2ml/m2 reduced the incidence on smut on cv.
Taurus (39 and 29 and 62% respectively), but not on Fortress. In the field, DADS
applications resulted in a small but significant reduction in incidence of onion smut. This
is the first report that synthetic germination stimulants have the potential to reduce smut
in onions.
Page 36
National Onion Research Conference
Towards improved control of botrytis leaf blight of onion
m
M A Mutschler', E. D. Cobb1, J. W. Lorbeer2
'Dept of Plant Breeding and 2Dept of Plant Pathology.
Cornell University, Ithaca, NY. 14853
Mutschler - Phone: 607-255-1660; Fax: 607-255-6344; E-mail: maml3@cornell.edu
Cobb - Phone 607-255-1714; Fax: 607-255-6344; E-mail: ec38@cornell.edu
Lorbeer - Phone: 607-255-7875; E-mail: jwl5@cornell.edu
m
***
m
m>
Botrytis leaf blight of onion (BLB), caused by Bolrylis squamosa, is a major disease of
onions in New York state Over 80% of the active ingredients applied to onions are
fungicides applied primarily to control BLB. Plant resistance offers an opportunity to
reduce fungicide use. B. squamosa resistance has been reported in A. roylei, a wild
species which produces fertile progeny with A. cepa. The F| hybrids between the two
species are as resistant as A. roylei. Resistant selections have been made from Fj and BC
populations, and are being used for production of further populations. Segregation data is
consistent with a dominant resistance that is inherited simply. Another source of
tolerance is A. cepa accession PI 273212, which Walters and Lorbeer identified as having
reduced BLB lesion number and lesion expansion. The inheritance of this tolerance is
not known. It is critical to know potential for the resistance found in PI 273212 and in A.
roylei to reduce disease without fungicide or with reduced levels or frequencies of
fungicide application. A cooperative 1PM project is determining whether or not the
resistance level found in this accession will permit control of BLB with fewer sprays or
lower concentrations of fungicide.
Susceptibility of onion seed stalks and flowers to infection by Aspergillus
niger Teigh
Karen L. Sirois and James W. Lorbeer
Cornell University
Ithaca, NY 14853
Phone: 607-255-7850; Fax: 607-255-4471; Email: Iclsl3@comell.edu, jwl5@comell.edu
The timing of onion seed stalk and flower susceptibility to infection by the fungus
Aspergillus niger Teigh was evaluated in greenhouse experiments. Onion seed stalks and
flowers received a one time inoculation of A. niger at 7 different stages of plant
development. Half of each treatment received a 48 hour mist chamber treatment. The
plants were allowed to mature with no further manipulations and the seed was collected
when mature capsules formed. Evaluation of the seed revealed a broad susceptibility
period to infection by A. niger. Plants inoculated prior to flowers opening through
mature capsule formation, which included 5 different stages of plant development, were
detected with high levels (82-100%) of A. niger on the seed. A seed infection level of
23% was detected on seed from plants receiving a one time inoculation to the immature
seed stalk. Observations of A. niger mycelial growth and sporulation within the lacunar
area were observed at the time of seed head collection. The addition of the mist chamber
treatment did not indicate any increases or decreases in infection levels.
Page 38
Garlic seed clove treatments for the control of penicillium decay
m
fm
R. M. Davis1, B. L Teviotdale1, J. J. Nunez3, and N. C. Goodell2
'University of California-Cooperative Extension, Davis
'University of California-Cooperative Extension, Kearney Ag Center
'University of California-Cooperative Extension, Kern County
31031 South Mount Vernon Ave, Bakersfield, CA 93307
Telephone: 80S-868-6222; Fax: 805-868-6208; E-mail: jnunez@ucdavis.edu
Poor garlic stands are often caused by Penicillium hirsutum. Although usually of minor
m
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vm
importance this disease occasionally accounts for substantial stand loss in California.
Laboratory and field trials were conducted to evaluate various hot water dip treatments
for the control of Penicillium decay. The experimental treatments were based on the
Lear/Johnson (L/J) seed piece dips for controlling nematodes (30 minutes in heated water
to 100 F then 20 minutes at 120°F, followed by a 10 minute cool tap water dip).
Formaldehyde was not used in any of the treatments. Various treatments differed by
adding disinfectants or fungicides in the 10 minute cool tap water dip. Materials tested
with the L/J treatment were sodium hypochlorite, benomyl, potassium sorbate, and
imazalil. Treatments were evaluated with wounded and nonwounded garlic cloves. All
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cloves were inoculated with spores of Penicillium hirsutum. Field trials were conducted
at two locations. Laboratory experiments were also conducted to assay the recovery of
Penicillium hirsutum from the treated garlic cloves. In field and laboratory trials, L/J
treatments with imazilil was the most effective and provided long-term protection against
seed piece decay. Sodium hypochloroite provided good control but had no residual
effect. The L/J treatment alone was also effective. There was little benefit to treating
healthy, nonwounded seed cloves.
Page 39
1998 Nalional Onion Research Conference
Severe outbreak of garlic rust disease in California.
S. T. Koike, University of California Cooperative Extension, Monterey County
R. F. Smith, University of California Cooperative Extension, San Benito County
R. M. Davis, Department of Plant Pathology, University of California at Davis
J. Nunez, University of California Cooperative Extension, Kern County
In 1998, severe rust disease of garlic was observed in several counties in coastal
(Monterey, San Benito, Santa Clara) and inland (Fresno, Kern, Kings) California.
Disease was widespread, and in many fields 100% of the plants were infected.
Symptoms were often severe, resulting in death of most leaves and significant stunting of
bulbs. At harvest affected garlic was substandard in quality and size, and some cultivars
shattered when collected. Based on the yellow orange urediospores and two-celled
teliospores with short pedicels, the rust was identified as Puccinia porri. Pathogenicity
was established by inoculating greenhouse grown garlic with isolates collected from the
field. Inoculated garlic developed rust after 9 to 12 days. The same isolates also infected
chives and several onion cultivars, but did not infect leeks or elephant garlic.
Commercial onion fields adjacent to or near infected garlic also became infected with the
rust, although disease in general was less severe than on garlic. Small plot fungicide
trials demonstrated that several fungicides were not effective against the disease (such as
Bravo, Maneb, Mancozeb), but that other, non-registered materials (Folicur, Quadris)
potentially will control it
Garlic rust is not a new disease to California, as it was
reported in the state as early as the 1930s. However, the severity, distribution of the
problem, and devastating crop loss appear to be unique developments.
Page 40
IW8 National Onion Research Conference
Damage threshold for thrips on processing onions in the San Joaquin
Valley, California
Richard L. Coviello,
U.C. Coop. Extension,
1720 S. Maple Ave, Fresno, CA
Phone: 209-456-7549; Email: rJ.csyiel!fl@«£davi8,.ffli«
Milton E. McGiflfen, Jr..
Dept. Botany and Plant Sciences
U. C, Riverside
Phone: 909-787-2430; Email: milt@ucracl.ucr.edu
Thrips cause considerable damage to onions. Localized tissue necrosis from their feeding
reduces the photosynthetic ability and nutrient availability to the plant for setting and
sizing the bulb, which consequently reduces yield. Reliable estimates of the population
level of thrips, which significantly reduces yield, have not been available for processing
onions grown in the San Joaquin Valley, California. Replicated plots were established at
the University of California West Side Research and Extension Center in 1994, 1995 and
1997. Sprays of cypermethrin at various intervals, plus an untreated check, resulted in
significantly different populations of thrips developing across treatments.
Thrips
populations were sampled weekly using whole plant samples until plant maturity. Thrips
counts were converted to cumulative thrips-days (CTD). Plots were harvested with a
mechanical digger and data for plot total weight, harvestable weight, bulb weight, percent
undersized and percent soluble solids were collected. Harvestable yields, bulb size and
percent soluble solids were negatively correlated with thrips population. The data
suggest that a range of 500 - 600 cumulative thrips-days or higher significantly reduces
yield.
Page 41
IW8 National Onion Research Conference
Evaluation of treatments for onion thrips control
m
Ronald F. L. Mau and Laura Gusukuma-Minuto
University of Hawaii at Manoa
Department of Entomology
3050 Maile Way, Honolulu, HI 96822
p*
More than 20 million pounds of onions are annually consumed in Hawaii. In-shipments
account for about ninety percent of the market supply. There is a well-established sweet
onion industry that produces about 2 million pounds for the local and export market. The
sweet onion and pungent onion industry is in an expansion phase. They hope to
significantly reduce or completely replace in-shipments.
r*m
Thrips tabaci is a key pest of onions. Growers feel that the pest is not readily controlled
using organophosphatc or carbamate insecticides. Field studies with EPA approved and
new insecticides were conduced to identify efilcaceous ones, to evaluate treatment
m
^
thresholds, and to evaluate an insecticide resistance management protocol. Insecticides
that were evaluated were diazinon (DIAZINON AG 500, Premiss Incorporated),
malathion (Malathion 5 EC, Drexel Chemical Company), methomyl (LANNATE L,
DuPont), and lamdacyhalothin (WARRIOR, Zeneca Ag Products). New insecticides
evaluated were chlorfenpyr (ALERT 2 SC, American Cyanamid), fipronil (Rhone
Poulenc), and spinosad (Dow Agrosciences).
Page 42
Evaluation of garlic extract for control of corn earworm, Helicoverpa
zea, in sweet corn
Benny Fouche & Dawn Brunmeier
U.C.C.E. San Joaquin Co.
420 S. Wilson Way, Stockton, CA 95205
Phone: 209-468-9491; Fax 209-462-5181
Helicoverpa zea is a major pest of sweet corn. The night-flying moth lays its eggs on the
silks of the com ear.
Insecticide applications of synthetic pyrethroids and or
organophosphates may be necessary every 2 to 3 days for a period of several weeks to
prevent infestation when the corn is susceptible. Five applications of Garlic Barrier plus
fish oil were made and compared to Asana, Success, JMS Stylet Oil and an untreated
control in a commercial planting with a high population of corn earworms At harvest,
the untreated control had a mean level of 48% worms in the ears. Asana provided the
best control with less than 2% worms. Garlic Barrier plus fish oil, JMS Style oil and
Success provided significantly better control than the untreated check with a range of 812% ears with worms present at harvest.
Page 43
Weed control with dimethenamid in onions growing on organic soils
L. A. Ellerbrock and B. L. Phillips
Department of Fruit and Vegetable Science, Cornell University, Ithaca, NY 14853
Phone: 607-255-6553; Fax: 607-255-0599; E-mail: Iae6@cornell.edu
Field and greenhouse experiments have shown that dimethenamid, applied at various
timings and rates, is relatively safe on onions growing on organic soils in New York and
would be very effective in enabling growers to manage yellow nutsedge, a weed that has
become increasingly difficult, if not impossible, for New York growers to control in
recent years. Dimethenamid would also be very useful in managing other problematic
weeds in onions, including Galinsoga, prostrate spurge, common ragweed, and redroot
pigweed. In most situations, dimethenamid rates of at least 1 Ib a.i./A are required for
adequate yellow nutsedge suppression, and in many cases, up to three such applications
are needed. Application of dimethenamid is compatible with the use of broadcast small
grain windbreaks for early season wind abatement, and tankmix applcations of
dimethenamid with grass herbicides for removal of windbreaks are effective and safe.
When applied in a tankmix with pendimethalin shortly after onion emergence at rates up
to 1 1b a.i./A, dimethenamid does not increase onion injury. Dimethenamid can also be
applied safely and effectively in a preemergence tankmix application with bromoxynil for
early season broadleaf weed control.
Page 44
y/wj
The use of foliarly-applied nitrogen fertilizers for early-season weed
control in onion seed crops
ra
Mike Murray
University of California Cooperative Extension
P. 0. Box 180
Colusa, California 9S932
i"9
Phone: 530-458 0577; Fax: 530-458 4625; email: mmurray@ucdavis.edu
_
Early-season weed management is a challenge for both fresh market bulb or onion seed
producers. This situation has been exasperated by the recent market withdrawal of the
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onion preplan! herbicide. Dacthal®.
There are effective post-emergence herbicides
available, so the immediate need is for effective weed control for the period from
seedling emergence to the 3 -4 true-leaf growth stage. Researchers have previously noted
that the use of foliar nitrogen fertilizers, such as ammonium nitrate, often results in weed
seedling control and minimal damage to young onions. The basis of this selectivity
appears to be the waxy cuticle on onions, which causes the fertilizer to run-off the
foliage. The fertilizer behaves as a salt on weed foliage and desiccates the plants. It
should be noted that most nitrogen fertilizers are not registered as pesticides in California,
and they can not be legally recommended or used exclusively for this purpose (although
they can be used as foliar fertilizers with "side-benefits" of weed control). Tests were
conducted in onion-seed fields in the lower Sacramento Valley in the fall of 1997 and
1998. Application timings, rates and fertilizer formulations were evaluated in multiple
tests. The fertilizers were applied in the onion "crook" through several true-leaf stages
and when the weeds had less than four true-leaves. The primary weed species present
was Shephardspurse (Capsella bursapasioris).
Safety to the crop, at all growth stages,
and weed seedling control was excellent.
Page 45
Session 5
Crop Culture,
Physiology,
Growth,
Storage
19'J8 National Onion Research Conference
Do onions have a critical plant size for bulb formation?
m
H.C Wien, B.S. Orenstein and LA. Ellerbrock
Department of Fruit and Vegetable Science
Cornell University. Ithaca, NY 14853
Phone: 607-255-4570; Fax: 607-255-0599; E-mail: hcw2@cornell.edu
fm
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When onion cultivars of a range of maturities are planted in spring in New York State,
they initiate bulbs several weeks after daylength and temperatures are adequate for
bulbing. Is this apparent delay in bulbing due to a minimum plant size, which a particular
cultivar might need to attain before bulbing could begin? The results of a series of field
and greenhouse plantings of 10 cultivars ranging in adaptation from Texas to Northern
Europe indicate that even the northern long day types can be induced to begin bulbing
when neck diameter is only 6mm, by sowing the seeds when temperatures and
photoperiod are optimum for bulbing. The bulbing ■ delay in spring plantings could
therefore be due to the somewhat lower temperatures prevailing then, or the need for
long-season cultivars to be exposed to more cycles of inducing conditions, before bulbs
are initiated, or both. Sowing in June leads to quick bulb initiation, but maturity is
prevented by the short daylengths and cool temperatures of fall. The implications of
these findings on selection of onion genotypes for environmental stability and yield will
be discussed.
Page 46
Alternative onion transplant production in Colorado
m
Michael E. Bartolo and Frank C Schweissing
Colorado State University, Arkansas Valley Research Center
27901 Road 21, Rocky Ford, CO 81067
Phone: (719)254-6321; Fax: (719)254-6312; e-mail: avrc@coop.ext.colostate.edu
f*1
P"
Onions grown from transplants are a significant part of the total onion crop produced in
Colorado. Bare-root transplants are grown in southern states and transported to Colorado
for planting in early spring. These transplants often harbor insects or diseases that infect
the growing crop and spread to direct-seeded onions.
Additionally, the cost and
availability of labor have made onion transplanting more difficult These studies were
conducted to examine the feasibility of alternative transplant production methods. In
1995 through 1998 several alternative transplanting methods were examined, including
containerized greenhouse production, in-field transplant production under row covers,
and fall planting-to-stand with and without row covers. Greenhouse-grown onion
Fm
transplants were free of pests and produced high quality onion bulbs Transplants grown
at a high density (392 cells per flat) and a lower density (200 cells per flat) produced
onions comparable in yield. Onion transplants grown locally under row covers had few
pests and resumed growth rapidly after transplanting. Unfortunately, hand labor inputs
m
were still significant. Planting to stand with and without row covers eliminated much of
the hand labor associated with traditional onion transplanting.
However, additional
research will be needed to identify varieties that are more winter-hardy and less prone to
bolting.
Page 47
HW8 National Onion Research Conference
Sudan grass Rotation for Improved Yield and Quality of Onions
Produced on Organic Soils in New York
John J. Mishancc
Cornell Cooperative Extension, 1PM Program
PO Box 497, Martin Rd.
"*•
Voorheesville, NY, 12186
Phone: 518-765-3532; E-mail: jmishane@cce.cornell.edu
m
rmfi
There are close to 5600 acres of onions grown on organic soils in Orange County, New
York. Over the years, onion growers have expressed an interest in learning ways to
increase fertility of their high organic (muck) soils. In some cases, fields have been in
uninterrupted onion production for two or more generations.
One idea is using
Sorghum/Sudan grass (Sudex) as a summer cover crop. The goal of these field trials with
Sorghum/Sudan grass were to figure out all the basic management considerations and
document the positive and negative results. After 6 years of in field trials, here is what
we have learned.
* Handling the large bio mass of Sudangrass takes some management. Planting rates
must be adequate to smother out weeds. Mowing half way through the summer
™
stimulates tillering and root penetration. Fields need to be cut and disced down early in
the fall to avoid trash and nitrogen deficiency problems the following spring
* Onions following Sudangrass can expect a 35% average increase in stand counts
* An average 20% increase in yield can be expected.
pw
p_,
* Following a Sudangrass rotation, growers can reduce onion planting rates by 15-20%.
* Quality was at least as good or better in the Sudangrass fields as compared to the
continuous onion fields Given the varying weather conditions, these results must be
considered very good. Onion growers who employed the Sudangrass rotation say the
onions following Sudangrass were their best onions and secondly, the growers felt the
numbers we found in our test plots were low.
™
For most years, the growers felt they
received an even bigger yield response than what we found in the test plots.
* Two years after a Sudangrass rotation, yields and stand counts were still positively
affected but decreased slightly from first year after rotation.
* With a five year whofe farm rotation, a grower will be ahead on return plus savings on
onion seed, labor and pesticides.
Page 48
.1 Of|i»n KcMifch ConfatlKc
Non-destructive measurement of quality parameters of stored onion
Zsuzsanna Fiistos \ J6zsef FelfbldiJ, Sandor IstellaJ
University of Horticulture and Food Industry
1 Postharvest Department
department of Physics and Control
1 Department of Vegetable Growing
H- 1118 Budapest Villanyi ut 35-43
Phone/fax: 36-1-466-52-94; E-mail: zsfustos@hoya.kee.hu
The onion is stored for eight to nine month every year in Europe, and gets consumed after storage.
The efficiency of the onion storage is determined by the storage time without any quality decay. The
damaged, rooted, or sprouted onion is worthless on the market. Because of the reasons above
storability and effective parameters are very important in the case of onion.
Most of the traditional methods and tools are based on destructive test (fructometers, precision
penetrometers) causing injury. Our aim was to find non-destructive method for measurement of the
firmness of onion bulb giving good correlation with the traditional methods and suitable to measure
the structural changes of the same piece of crops during the storage period.
The tested samples were stored at different conditions. One part of the amount was kept in refrigerator,
at 4°C (cooled). In the cellar the temperature was at 12-13°C. We have measured and calculated the
colour ,the shape, the firmness parameters, coefficient of elasticity, secant modulus, acoustic stiffness
coefficient and the sprout length and evaluated the correlation among them. No significant differences
were found in visual parameters during the storage methods.
Our results give possibility to determine characteristic ranges of the firmness parameters for different
quality (sprout length) categories
Both of the secant modulus and the acoustic stiffness coefficient were found to be suitable to classify
the samples according to the sprout length categories. The acoustic response method - due to it's non
destructive nature and real- time result - can be the base of on-line selection method.
a| Onion Rcwch Conference
Long-term storage potential of garlic (Allium sativum L) with
cryopreservation and regeneration in tissue culture
Richard Hannan and Denise Garoutte
USDA, AM, Western Regional Plant Introduction Station
59 Johnson Hall, WSU, Pullman, WA
Phone: 509-335-1502; Fax: 509-335-6654; E-mail:
m
m
The USDA, ARS, NPGS maintains a collection of Allium species at the Western Regional
Plant Introduction Station, Pullman, WA. The collection currently numbers 823 accessions, with
over 230 vegetatively propagated. Clonal accessions are planted in the fall and harvested the
following summer. This subjects germplasm to potential loss from adverse weather or disease.
Research was conducted to explore cryopreservation under liquid nitrogen (LN) for long-term
storage of garlic. Tissue culture maintenance was rejected due to cost, space and labor
requirements, and the potential for genetic drift.
The objectives were to reproduce existing
protocols for tissue culture establishment of garlic, develop a successful protocol for LN storage
of garlic clones and test the effectiveness of the protocol over a range of genotypes.
|PP*
m
immersion into LN, plant tissue must be chemically conditioned
Prior to
Of the conditioning treatments
tested, ones which used 50% to 74% PVS2 and 50-26% water/sucrose solution were most
effective. Dehydration and pre-treatment on a high sucrose medium favored survival
Effect of
explant size on survival indicated that either 2mm or 5mm explants survived and that the
conditioning treatment was most crucial. No explants survived thawing in temperatures of 40°C
Survival was best at 20 minutes and I7°C. In the study of genetically different clones, results
were statistically inconclusive due to losses from contamination. Data indicates that use these
protocols for crypreservation of the USDA garlic collection is feasible.
Page 50
Posters
IW8 NiliwMl Ottian Re»t»ch Conference
.
—
Fall-planted onion variety trials at New Mexico State University
Christopher S Cramer, Jose Luis Mendoza and Joe N. Corgan
Department of Agronomy and Horticulture, New Mexico State University
MSC 3Q, Box 30003, Las Cruces, NM 88003-8003
Phone: 505-646-2657; Fax: 505-646-6041; E-mail: ccramer@nmsuvml.nmsu.edu
Forty-two fall-planted onion varieties and lines were tested in 1998 at the Fabian Garcia
Agricultural Science Center in Las Cruces, NM. Four replications of 2.5 m-long-plots for
each entry were planted on 16 September 1997 with 4 rows per bed per plot. This planting
date was chosen to evaluate varieties for bolting resistance. Varieties were arranged in a
subplot based upon approximate bulb maturity (early, intermediate, late) for fall planting in
Las Cruces, NM. Varieties were harvested when 80% of the tops were down in all four
replications. Varieties were evaluated for maturity date, pink root and bolting resistance,
total and marketable bulb number and weight, and percentage of marketable bulbs. Bulb
maturities ranged from 14 May ('Buffalo') to 19 June (NMSU 9712). Most early-maturing
'NuMex' varieties and NMSU breeding lines exhibited a low percentage of bolting along
with 'Ibex' and 'Buffalo'. Most entries except 'Buffalo' exhibited moderate to high levels of
pink root resistance. Some of the high-yielding (based on weight) entries included 'NuMex
Sunlite', 'NuMex Mesa", 'NuMex Starlite', 'NuMex Dulce*. NMSU 96-11, 'Caribou', and
'Ibex'.
'
Poster I
IOTH N«lion»l Onion Rj«tMch C'onrtTcnc-
Seed yield and morphology of CMS onion populations possessing the
cytoplasm of A. galanthum
Michael J. Havey, USDA-ARS and Dep. of Horticulture
The primary source (S cytoplasm) of cytoplasmic-genic male sterility (CMS) used to produce
hybrid-onion (Allium cepa) seed traces back to a single plant identified in 1925 in Davis, CA.
Many open-pollinated populations also possess this cytoplasm, creating an undesirable state
of cytoplasmic uniformity. Transfer of cytoplasms from related species into cultivated
populations may produce new sources of CMS. In an attempt to diversify the cytoplasms
conditioning male sterility, the cytoplasm of Allium galanthum was backcrossed for six
generations to bulb-onion populations. The flowers of galanthum-cytoplasmic populations
possess filaments with no anthers and upwardly curved perianth, making identification of
male-sterile plants easier than Tor either S- or T-cytoplasmic male-sterile onion plants. Mean
seed yield per bulb of the galanthum-cytoplasmic populations was measured using flies as
pollinators and was not significantly different from that of one of two S-cytoplasmic malesterile F| lines, a T-cytoplasmic male-sterile inbred line, or N-cytoplasmic male-fertile lines
Male sterile lines possessing S and galanthum cytoplasms were crossed with populations
known to be homozygous dominant and recessive at the nuclear locus conditioning malefertility restoration of S cytoplasm and progenies scored for male-fertility restoration.
Nuclear restorers of S cytoplasm did not condition male fertility for the galanthumcytoplasmic populations It is intended that these galanthum-cytoplasmic onion populations
be used as an alternative male-sterile cytoplasm for the commercial production of hybridonion seed.
Poster 2
1998 Nuioial Onion Rqgfdi Confaenct
The Vidalia onion industry: past, present, and future
"*<
George Boyhan
University of Georgia, East Georgia Extension Center
PO Box 8112, GSU, Statesboro, GA 30460
Phone: 912-681-5639; Fax: 912-681-0376; Email: gboyhan@uga.edu
fm
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rm
The Vidalia onion industry that began in 1931 has seen slow but steady growth until the
1970s. In the 1970s a concerted effort was launched to market these onions nationally,
which resulted in a tenfold increase in acreage over the next decade. In 1986, Georgia gave
recognition and legal status to the Vidalia onion industry, defining the 20 county production
area. This was followed in 1989 with Federal market order 955 that gave the industry legal
status on a national basis. In addition, in 1989 the industry began to adopt controlled
atmosphere (CA) storage The size of the industry has more than doubled since the mid1970s and stands at more than 14,000 acres today. Problems the industry faces include new
diseases not seen in this region before, labor problems associated with the use of foreign
labor, increased competition, problems with CA storage and problems associated with
adoption of mechanized harvesting.
Poster 3
1998 N.lion.1 Onion RtMMdi Confacnw
Onion and garlic research in India
H.S. Dalla, AS. Sidhu and S.S. Bal
FW
Punjab Agricultural University, Ludhiana 141 004 Punjab INDIA
im
Onion and garlic both are important commercial vegetable crops among various Alliums
growth in India. India ranks first in the hectarage of onion and second in garlic, comprising
0.36 million hectare under onion and 0.08 million hectare under garlic. In production
however, it stands second and fourth with 3.6 million tons and 0.26 million tons respectively.
India exported 446,000 tons of onion valued at Rs. 2430 million which accounted for about
m
P"*
™l
75 per cent of total foreign exchange earning among fresh vegetables There has been a
steady increase in both area and production in the last decade Besides, the traditional winter
season crops, the summer crop is now being grown successfully in the north and eastern parts
of the country. In spite of this, productivity remains lower than the world average. The low
productivity in these crops has been accounted or a host of factors including diverse agroecological situations, lack of suitable varieties and non scientific cultural practices, etc.
Several biotic and abiotic factors have also been identified as limiting the productivity.
Major emphasis has been put on the improvement of the productivity Special attention is
being paid to build a large germplasm base for these crops. Developing lines with higher
levels of resistance to major prevalent diseases besides developing tolerance to high
temperature and moisture prevalent have been earmarked in priority areas
Poor storage
quality of onion bulbs is one of the major constraints which require immediate attention.
Heterosis breeding in onion has also been initiated. India has developed several important
im
cultivars of onion and garlic for different agro-climatic zones and are classified on the basis
of size, season and skin colour of the bulbs Most popular among them for onion are Pusa
m
!
Red, Pusa Madhvi, N-2-4-1, Punjab Selection, Punjab Red, Round, Punjab Naroya, ALR,
Pusa Ratnar, HISSAR - 2, Arka Niketan and Arka Kalyan in red types whereas Pusa white
Flat, Pusa white Round, Pb-18, Punjab white, Udaipur • 102, N-257-9-1 and RHR white
among white types have been developed for rabi season and ADR, N-53, B-780 and Arka
Kalyan for Kharif season in case of garlic Agri found white, G-l, G-SO, Godavari Sweta have
been developed.
Poster 4
IW* Niliwul Opii»p H^rdi Conference
.
Onion growth and N uptake in southeastern Colorado
m
Ardell D. Halvorson, Ronald F. Follett, and Michael E. Bartolo
USDA-ARS and Colorado State University
P 0 Box E, Fort Collins, CO 80522
Phone: 970-490-8230. Fax: 970-490-8213; e-mail: adhalvor(S)lamar colostate edu
Onion (Allium cepa) production in southeastern Colorado may be contributing to high levels
ofNOj-N in irrigation and groundwater supplies. Normal N fertilization rates range from 100
m
^
TSR
to 400 kg N/ha. Frequent irrigation of onions is needed at the seedling establishment stage to
help onion survive the hot, dry climate of southeastern Colorado. Therefore, the potential for
N leaching is high. We conducted a study in 1998 to examine the growth and N uptake
patterns of onion grown on a Rocky Ford silty clay soil. Plant samples were collected at two
week intervals from April 22 through mid-September 1998 from plots receiving no N
fertilizer and plots receiving 224 kg N/ha The N fertilizer (KNOj) was applied in split
applications of 112 kg N/ha each on May 18 and June 25, 1998 In addition, labeled N
fertilizer (112 kg N/ha as KN1' O3) was applied to separate plots that had received 112 kg
N/ha of non-labeled KNOj at each of these N application dates. A randomized complete
block design with three replications was used. Preliminary results indicate that biomass
production was very low during the first 76 days following planting with a rapid increase in
biomass production during the next 24 days. No response of onion to N fertilization was
observed during the first 106 days of growth. Onion biomass production and N uptake
patterns from planting to harvest will be presented.
Poster J
1998 Nniiofwl Onion Reswch Conference
Irrigation scheduling to optimize yields and reduce leaching of nitrates for
Maui sweet dry onions
i™1
Robin S. Shimabuku and I-Pai Wu
Hawaii Cooperative Extension Service
University of Hawaii
310 Kaahumanu Ave. B Idg. #214
Kahului, HI 96732
And
Department of Biosystems Engineering
pm.
University of Hawaii at Manoa
3050 Maile Way
Honolulu, HI 96822
Phone: (808) 244-3242; Fax: (808) 244-7089; email: Shimabukurtgavax ctahr hawaii edu
p>
Phone: (808) 956-8809; Fax: (808) 956-9269; email: ipaiwu@hawaii.edu
Deep seepage of nitrates in agricultural fields is an important non-point source pollutant for
underground water resources in Hawaii. The leaching of nitrates can be minimized with a
Fm
highly uniform drip irrigation system and appropriate scheduling based on onion water
requirements.
Three field experiments were conducted from 1996 to 1998 in Kula, Maui using 10 different
irrigation scheduling rates. A simple drainage lysimeter was installed for each treatment to
determine the amount of nitrate leaching out from the root zone
&SH
Results from these experiments have shown the ET (evapotranspiration) rate were very
f™
similar to the total evaporation rate for the crop cycle to obtain optimum yields and that deep
seepage only occurred in irrigation treatments exceeding the ET for optimum yield. This
data suggest using a Class A evaporation pan to determine the water requirement of onions
for given period of time. For every inch of water being evaporated by the evaporation pan,
an acre-inch (27,154 gal) of water needs to be applied per acre of onion crop. By using this
method, the water requirements of onions can be determined for optimum yields and to help
minimize groundwater contamination of nitrates by over irrigation
Poster 6
1998 National Onion Rwewch Conference
Effects of Transplant Date and Transplant Size on Production, Quality,
and Pungency of Sweet Onions
m
Mark Gaskell, Marita Cantwell, Xunli Nie, Richard Smith, Ben Faber, and Ron Voss
Department of Vegetable Crops, University of California, Davis, CA 9S616
Phone: 805-934-6240; Fax: 805-934-6333; Email: mlgaskell@ucdavis.edu
im
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m
The production of short day sweet onions in temperate zones is limited to areas with mild
winters and appropriate day lengths for normal development. Previous studies in Coastal
California showed excessive bolting with short day onions transplanted prior to early
January. Later transplanting and smaller transplant size can reduce bolting.. This study
evaluated 4 short day cultivars grown in 3 transplant tray sizes (280, 392, or 595 cells per
tray) at 3 transplant dates (Jan.27, Feb. 13 or Feb. 27) Bulb sizes generally declined with
each successive transplant date across cultivars and cell sizes. The smallest transplant size
produced the smallest onions in all cultivars in the Jan. 27 and Fcb 13 plantings Harvested
bulb size and transplant cell size was inconsistent with the latest planting date, with smaller
bulbs from the largest transplant size in 3 of the 4 cultivars. Generally transplant date did not
affect pungency, dry weight, or sugar concentration, with average values across cultivars and
locations of 4.2 (range = 2.9-5.6) umole pyruvate/g fr.wt., 7.9 (range = 6.6-10 2) % dry wt,
and 42 (range = 29-49) mg/g fr. wt., respectively. Location, however, resulted in important
differences, with pungency values at 2 locations of 4.7-5 0 and at the other two of 3.3-3.6
umole pyruvate/g fr.wt.
Poster 7
I'W» N«Ik«mI Onion knalJl Confctciwc
Synthetic garlic oil reduces viability of Sclerotium cepivorum sclerotia and
incidence of white rot on onions
McDonald MR and Hovius MHY
Muck Crops Research Station, University of Guelph
1125 Woodchoppers Lane, Kettleby, ON, LOG 1 JO
Phone: 905-775-3783; Fax: 905-775-4546; E-mail. mrmcdona@guelph.ca
Allium white rot (Sckrotium cepivorum) is a major threat to the onion industry in Canada,
where most of the crop is grown on organic (muck) soils. Disease incidence can exceed 65%
in commercial onion fields. Materials such as onion oil and synthetic garlic oil are known to
stimulate the germination of sclerotia of S. cepivorum in the absence of a host, reducing the
soil populations [1,2]. Trials were conducted in commercial onion fields and in the
greenhouse to determine the potential of germination stimulants to reduce sclerotia
populations and subsequently control white rot on onions. Two germination stimulants,
diallyl disulfide (DADS) and N-dipropyl disulfide (DPDS), were applied to field plots (65%
organic matter, pH 5.5-6 5) in the Holland Marsh, Ontario, naturally infested with the
pathogen. The materials were injected at depths of 10 and 20 cm, at rates of 10.01/ha in
500l/ha of water at sites 2 and 3 in 1994, at sites 4 and 5 in 1995 and 1996, at site 6 in 1996
and at sites 7 and 8 in 1996 and 199.7. Only DADS (5.01/ha) was applied to site I in 1994.
Adjacent untreated areas were used as controls with six replications per treatment. Onions
were grown at sites 1, 2 and 3 in 1995, sites 4 and 5 in 1997 and sites 6, 7 and 8 in 1998 and
evaluated for white rot at harvest. Mesh sacks of 100 sclerotia of S. cepivorum were placed
in pots of organic soil treated with DADS and DPDS (1 ml/m2 in 50 ml water) and recovered
at monthly intervals.
Sclerotia were plated on potato dextrose agar to test for viability.
Incidence of onion white rot was relatively low in all years (maximum 13.7 and 13.0%,
respectively). Single treatments with DADS significantly reduced white rot on onions at
sites I, 2 and 6 (reductions of 72, 88 and 81% respectively), while two applications of DADS
reduced white rot by 99, 100, 87 and 96% (sites 4, 5, 7 and 8 respectively). Exposure of
sclerotia to DADS and DPDS in pots of treated soil reduced viability after 2 and 3 months,
but DADS much more effective than DPDS (18 and 60% viability, respectively, compared to
99% for the water check). DADS is an effective soil treatment for the control of onion white
rot in organic soils, especially when applied twice prior to onion production.
The
effectiveness of DPDS may be improved by increasing the rate.
References
1. Crowe FR, J Dobons and T Darnell. 1994. Proceedings of the 5* International Workshop
on Allium White Rot, 5.2b
2. Utkhede RS and JERahe, 1981. Canadian Journal of Plant Pathology. 4:79-80
Posler 8
IWX Nalionul Onion Kc»c»ich ConftKIKC
Base temperature for garlic growth determinations in the white-garlic type
J. A Portela, J. L. Burba and S. Lanzavechia
Garlic Project, EEA La Consulta INTA
CC 8 (5567) La Consulia, Mendoza, Argentina
Fax: +54-622-70 753, E-mail, elaconsulia@ima.yov ar
Temperature is the main environmental factor that affects growth and development of garlic
(Allium sativum L.). Although many studies on its physiology have been carried out alt over
the world, few of them have tried to describe associations between temperature and growth
so far. The aim of this work was to establish base temperature for the white garlic type
(physiological group III for Argentine and French classification). Three monoclonal cultivars
- Lican INTA, Nieve INTA and Union - were grown in growth chambers at constant
temperature (0, 6, 9, 12, 2I°C) and in the field. Clove sprouting as the appearance of the
sprout leaf over the ground in the first case, and the number of foliage leaves in the second
was periodically recorded. The physiological base temperature in the sprouting phase was
established below 0°C for all cultivars. In the field, a base temperature of 0°C was more
appropriate for use in a linear system of heat units. Even though it was not possible to
differentiate minimum temperature requirements among cultivars, they showed diverse
trends of response as the temperature varies
Poster 9
IW8 Nilioml Onion Kwoi
Development of a bioassay to determine the presence of specified fungal
pathogens of onion.
Karen L. Sirois, David P. LoParco, and James W. Lorbeer
Cornell University
Ithaca, NY 14853
Phone: 607-255-7850; Fax. 607-255-4471;
Email: klsl3@cornell.edu, dpll@ cornell.edu, andjwl5@ cornell.edu
A bioassay was developed to determine if pathogenic fungi detected on onion seed were
capable of infecting developing seedling tissue. Spores of an Alternaria sp, AspergUlus sp.,
AspergUlus niger, Fusarium sp., and Penicllium sp. were used to inoculate onion seed and
were placed in the soil growth medium to determine the infection levels in the onion seedling
tissues. Seedling tissues were examined at various ages for the presence of the fungi used in
the inoculations. The seedling parts examined were the roots, basal plates, lower leaves, leaf
tips, and the seed coat remnants if they remained attached to the leaf tips. Isolation of the
inoculated fungi was most consistent in treatments which utilized AspergUlus niger and the
Fusarium sp. Seed inoculations and soil growth medium placement of spores produced
similar infection levels. The infections appeared to begin in the root systems of the seedlings
and moved systemically into the basal plates and lower leaves.
Poster 10
1W8 N.lioml Onion R<««rch ConfwciK*
Pest Management Guidelines: Onion and Garlic from the University of
California Statewide IPM Project
R. Voss, R. Coviello, W. Chaney, W. Bentley, S. OrlofT. R.M. Davis, F. Laemmlen, C.
Bell.H. Agamalian, D Cudney, B. Fischer, B. Westerdahl, U. Kodira, ML. Flint,
B. Ohlendorf
IPM Education and Publications
University of California, Davis CA 93616
Phone: 530-752-7821; Fax: 530-752-9336; b1ohkndorf@ucdavis.edu
l^r
ra
The UC IPM Pest Management Guidelines for Onion and Garlic contain the official
University of California suggestions for managing insect, mite, disease, nematode, and
weed pests. Written by UC faculty and advisors with expertise in onion and garlic, the
guidelines represent the best information currently available and are intended to assist
growers in making the best choices in an 1PM program. Included in each pest section is a
brief description of the pest, its damage, monitoring and treatment timing suggestions,
nonchemical and/or cultural control methods, pesticides, and special problems. Guidelines
are updated as pest management options (including pesticides) change. UC IPM Pest
Management Guidelines are available for approximately 40 California crops. The Onion
pb
and Garlic Guidelines can now be purchased together with a new color photo supplement
r"!r
illustrating common pests as UC DANR Publication 3339-PS3A. The UC Statewide 1PM
Project has also produced comprehensive 1PM manuals for 15 major California crops
including potatoes, tomatoes, lettuce and cole crops, alfalfa, cotton, strawberries, and
numerous fruit and nut trees Guidelines with color supplements have been produced for
onion/garlic, sugar beet, and dry beans. These publications may be purchased from UC
DANR Communication Services or from UCCE County offices. Guidelines may also be
viewed on the web at <hltp://www.ipm.ucdavis.edu>.
Poster 11
199* Nilioml Omon Koewh Confcttin-v
Polymorphism in AUinm species revealed by Simple Sequence Repeats
Ellen PefTley1, Anfu Hou1, and Laurence Trueman2
'Department of Plant and Soil Science, Texas Tech University, Lubbock, TX 79409, USA;
horticulture Research International, Wellesbourne, Warwick, CV 35 9EF, UK.
Simple sequence repeats (SSRs), also referred to as "microsatellites", are tandemly repeating
short nucleotide units of 6bp or less. SSRs are relatively abundant in plants, highly variable,
and easily detectable by PCR. For these reasons, these are a highly desirable class of
molecular markers. An initial investigation of SSRs in onion was conducted at Horticulture
Research International, Wellesbourne. In the study reported here, DNA clones containing
SSRs were identified from small insert random genomic pJVl DNA libraries of leek (Allium
ampeloprastim). Oligonuclcotide primers flanking the SSR regions were designed and the
amplification conditions optimized. These primers were used to amplify genomic DNAs
from cullivars of several species ofAllium.
Poster 12

National Onion (and other Allium) Research Conference

Transcription

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