stone fruit rootstocks

STONE FRUIT ROOTSTOCKS
BACKGROUND AND LATEST INFORMATION
Piet Stassen
ACKNOWLEDGEMENTS
FUNDING
• ARC Infruitec-Nietvoorbij
• SASPA
• CFPA
• DFTS
ASSISTANCE
Kobus de Kock, Ria Roode and Johny Daniels
Dr Marde Booyse (stats)
INTRODUCTION
Kakamas seedling and Marianna remains popular/widely use
Reasons: Reliable over time, lower costs (royalties), ease of
propagation and take for nurseries, less come backs after plant in
orchard, information on new rootstocks limited especially for certain
soil types, die-back occurrence, compatibility, adaptability and other
uncertainties.
New clonal hybrids and other rootstocks from different breeding
programmes over the world are available. Their ability to optimise
scion performance have been widely evaluated for South African
situations.
Objective: To look at the information available and discuss the bigger
picture
What do we want from a rootstock?
• To increase yield and quality above that of the standard rootstocks
in each situation or otherwise stick to what we have
• Give us resistance to abiotic stresses (calcareous soil)
• Resistance to pest and diseases (plant-parasitic nematodes)
• Adaptability to our variability in soil textures
• Adaptability to climatic conditions
• To tolerate rising water tables during rainy periods
• Provide the necessary synchronisation between the scion and roots
FIELD EVALUATION RESULTS: High pH sites
• Table 1 Excelsior Worcester: 33% clay and silt, 57% sand. pH (KCl) 7.9.
Nematodes low. Artic Star
• Previous year 2014 before treatment for chlorosis: Flordaguard 80% yellow,
Tsukuba, Kakamas, Guardian 40%. Viking, Atlas, Cadaman 20% and Garnem
less than 10%
• Third harvest: Atlas 30.26 t/ha, Garnem 28.53, Viking 28.31, Guardian 28.00
and Cadaman 27.12. No statistically difference.
• Kakamas, Penta, Flordaguard and Tetra respectively, 25.9, 24.65, 19.8 and
19.35. Effect of pH having effect, but treatment for lime induced iron
chloroses was accidentally done.
• Fruit weight: Garnem and Viking best but not sig better than Atlas, Monegro,
Cadaman, Kakamas and Tetra. Tetra and Flordaguard smallest
• Strongest growth: Felinem, Garnem and Cadaman
Excelsior conclusions
• Effect of high pH show effect on Kakamas, Penta, Flordaguard and
Tetra in terms of production and Tskuba 4 and Flordaguard in terms
of fruit weight. After one more season differences between
rootstocks clear. High potential soil favours Kakamas.
• In terms of yield and fruit size: Atlas, Monegro, Garnem, Viking,
Cadaman promising. Three more seasons.
Table 2 Sonskyn, Robertson. African Delight
• 10.6 silt and clay, 89.4% sand, pH 7.6, High numbers of ring
nematodes
• After five harvest seasons: GF 677 best average yield, but not sig
better than Cadaman. Best fruit weight: Cadaman, Atlas and Chuche
Picudo, but not sig better than GF 677
• Effect of ring on fruit weight of Marianna, Maridon and Tsukuba 5
evident sig also effect of iron chlorosis on Flordaguard, SAPO 778
and SAPO 778 seedling
• Cadaman induces strongest growth but not sig better than GF 677,
Atlas, Viking, Marianna, Flordaguard and SAPO 778.
Conclusions Sonskyn
• Over five harvest seasons, GF 677 and Cadaman performs the best
in terms of yield and fruit weight followed by Atlas under condition
of high pH and ring numbers as well as sandy soils.
• Marianna, Maridon and Tsukuba: reduced fruit weight under these
conditions
• SAPO 778 and Flordaguard not suitable for high pH
• Ring nematodes have a high reproduction index on Tsukuba,
Marianna and Maridon
Roodehoogte, Robertson. African Rose
• 25% silt and clay, 75% sand. pH 7. High spiral and increasing ring.
Third harvest.
• Best performance in terms of yield and fruit weight: Atlas, GF 677,
Marianna, Garnem. Lowest yield and fruit weight: Penta and Tetra
• Higher soil potential, lower pH and lower ring until harvest than
Sonskyn. Future results will show effect of increasing ring
Middelplaas, Bonnievale. Alpine
• 17.7% clay and silt, 82.3% sand. pH 7.6. Second harvest. Ring
moderate to high, root lesion moderate.
• Chlorosis: Kakamas 100%, Viking, Atlas about 40% and GF 677,
Cadaman and Garnem 20%. Penta and Tetra removed due to very
poor growth.
• In terms of yield and fruit weight no sig difference between Atlas,
Viking, Garnem, Cadamen and GF 677. Kakamas sig lower
High pH Conclusions
• Excelsior, low ring, high potential soil: Atlas, Garnem, Viking and
Cadaman. GF 677 planted later
• Sonskyn, high ring, sandy soil: GF 677, Cadaman, Atlas. No Garnem in
trial
• Roodehoogte, high potential soil, increasing ring: Atlas, GF 677, Garnem
and Marianna
• Middelplaas, moderate to high ring (increasing): Atlas, Viking, Garnem,
Cadaman and GF 677
• It is clear that the rootstocks: Kakamas seedling, Flordaguard, SAPO 778
clone and seedling, Penta and Tetra and Guardian cannot be
recommended for high pH soils
Sandy soils (more than 90% sand)
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Bufland, Mookgophong (Naboomspruit), Alpine.
Two experimental sites. Results over 5 harvest seasons.
91% sand, pH 5.8. RCU 170-270, ICU 240-300. Moderate ring, high spiral
1) Flordaguard and Cadaman best performance in terms of yield and fruit
weight. Kakamas only 50% of yield of Flordaguard and fruit weight 14%
less than Flordaguard. Atlas not sig lower than Cadaman.
• Guardian and Tsukuba sig better than Kakamas in terms of yield but fruit
weight same. SAPO 778 seedling, GF 677 and Kakamas performs poorly in
under these conditions
Sandy soils
• Bufland 2, 5 harvesting seasons
• Flordaguard sig higher yield than Atlas, Viking, SAPO 778 clone,
Penta and Tetra. Fruit weight of trees on Flordaguard, Atlas and
SAPO 778 same.
• Yield on Penta and Tetra only about 23% than Flordaguard and 9%
smaller fruit weight
• Conclusions Bufland: Flordaguard ideal for sandy soils where ring is
moderate, low chill and early cultivar. Cadaman and Atlas as
alternatives. Viking if irrigation is good during summer months but
risks. Too warm for SAPO 778, Penta and Tetra. Guardian?
Sandy soils
• Riverside, Simondium. Summertime on 9 rootstocks, 95.3% sand, pH 5.8.
RCU 470. Short periods of high water tables. Two years harvest data. Area
tree die-back (Sundew/Marianna). Moderate ring nematodes
• Best performance: Mr 2/5, Tetra, Kakamas, Penta and Krymsk 1
• Die-back: SAPO 778 seedling 6/10, SAPO 778 clone 6/10, Cadaman 4/10,
Viking 4/10. Rest of orchard on Flordaguard, only few trees died in whole
orchard. Because of possibility of high water table Flordaguard and GF 776
was not included in trial.
• Analysis of trees show Leucostoma and Botryosphaeria
• Conditions at this site and pruning practises put trees under stress and
predispose trees to opportunistic latent fungal diseases. Synchronisation of
scion and rootstock (SAPO 778) may also play a role.
Sandy soils. Elkana, Simondium. African Delight
• 93.4% sand, 5 harvest seasons, moderate/high ring, but treated
regularly and Telone treatment before plant. High water table but
drainage system and ridges. RCU 450. Best cumulative yield over 5
years Maridon but not sig better than Marianna, Flordaguard, SAPO
778 and Viking. No sig difference in fruit weight
Conclusions Sandy soils
• Flordaguard can handle high % sandy soil with moderate ring in low
chill areas for early cultivars. Alternatives: Cadaman and Atlas
• Areas prone to fungal diseases and bacterial canker and where
stresses occur use peach rootstock and not rootstocks with almond
parent (Flordaguard? Guardian?). Maridon instead of Marianna.
• SAPO 778 synchronisation and almond?
• High water table: drainage and ridges. Marianna and Maridon best
but need to treat for ring. More aggressive fruit thinning necessary
than at Sonskyn. Flordaguard too risky. Viking and SAPO 778 only if
no standing water.
Soils with between 50 and 70% sand. Normal
pH. RCU 400-600.
• Wakkerstroom, Bonnievale. Old grape land. High root lesion, low
ring, 27% clay and silt, pH 6.4. Two harvest seasons
• Best performance in terms of yield and fruit weight: Kakamas,
Garnem, GF 677. Atlas and Cadaman in between. Viking, Tetra and
Penta poor performance
• Ripening: Kakamas few days ahead of Garnem. Atlas and Viking one
week later than Kakamas. GF 677 over irrigated after plant. Many
died of Botryosphaeria
Higher potential soils
• Timberlea, Stellenbosch. Summersun. 52% clay and silt, pH 6.5.
Second harvest season. Severe brown rot due to rain. Low ring.
• Best performance in terms of yield and fruit weight: Atlas, Guardian.
Followed by Viking, SAPO 778 seedling, SAPO 778 clone and
Kakamas. Poor performance Flordaguard.
Higher potential soils, Stellenbosch. 58% clay
and silt
• Sensation, Laetitia and Sunbreeze. One harvest season. Viking,
Maridon, Marianna, Atlas and SAPO 778 seedling, Guardian good
performers. Too early for any conclusions
Conclusion Higher potential soil
• Depending on the situation we have: Kakamas (soils with no
limitations), Atlas, Viking, Maridon, Marianna, Garnem, Guardian
(not very low chill)
Overall Conclusions
• High pH, High ring, sandy: GF 677, Cadaman, Atlas
• High pH, high pot soil, low ring: Atlas, Garnem, Viking, Cadaman, GF 677
• High sand, god drained low chill, early cultivars, moderate ring:
Flordaguard. As second alternatives: Cadaman and Atlas
• Areas prone to fungal and bacterial problems in sandy soils: Peach
rootstocks better than peach/almond. Flordaguard and Guardian if no
water risk, Maridon. Not GF 677 and SAPO 778
• High water tables in winter/spring: Marianna/Maridon on ridges and soil
drained. Treat for ring.
• Depending on situation: Kakamas, Atlas, Viking, Maridon, Marianna,
Garnem, Guardian
PARENTAL BACGROUND AND CHARACTERISTS
OF COMMERCIAL STONE FRUIT ROOTSTOCKS
• SEE TABLE 3
Things that need attention
• Propagation innovations to make live easier for nurserymen
• Nurseries specialising in specific rootstocks
• ARC rootstocks bred for ring tolerance need to go into the field
• Detailed integration of all information when more data on new
rootstocks are available
END
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