Tetraploid perennial ryegrasses

FACTfile
Grass Experts Since 1904
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Tetraploid Perennial Ryegrasses
Description
“Ploidy” refers to the number of chromosomes in an organism’s cells. A normal perennial ryegrass plant contains
two sets of chromosomes per cell (referred to as diploid), which results from the fusion of two haploid (single ploid)
gametes, a sperm cell and egg cell, during fertilisation. This first diploid cell then replicates and divides countless times
to produce a diploid perennial ryegrass plant.
By inhibiting cell division (usually with the use of the chemical colchicine) at a very early stage, plant breeders can
create tetraploid plants, which contain four sets (tetra = four in Greek) of chromosomes in every cell. This process has
long been part of a breeder’s repertoire in the search for large productive ryegrass varieties for use in the agricultural
forage market.
Advantages
Tetraploid ryegrass varieties are characterised by various traits – they are generally larger plants with broader leaves
and fewer tillers, offering high sugar production, good disease tolerance, high seed yield, and a dark green colour
(high chlorophyll production). Unfortunately, many of these advantages, whilst useful in forage varieties, could be
viewed as negatives in amenity cultivars.
Disadvantages
Large, broad-leaf perennial ryegrasses have obvious disadvantages in a sports or turf scenario. The shoot density of
these plants is particularly poor, producing an open sward that allows unwanted ingression from weed species such as
Poa annua. The high sugar content of tetraploids in the form of soluble carbohydrates makes for lush, soft palatable
leaves rather than tough fibrous cell walls. Inevitably, tolerance of close mowing and the ability to withstand heavy
wear are subsequent and significant downsides.
Sports Uses (Mown at 25mm)
Sports
When these cultivars are trialled under a regime of wear simulation, their performance is significantly compromised,
so other claims such as “strong winter growth”, “robust growth”
or “fast recovery” can be largely disregarded in a
Table S1s
winter sports pitch environment. Independent trials, such asTetraploid
those ryegrasses
by the BSPB and STRI, clearly highlight the obvious
negatives of current “amenity” cultivars. Table S1s in Turfgrass
Seed
2015 can be used as a direct comparison against
TetraploidScultivars of perennial ryegrass are starting to be used in specialist seed mixtures for sports uses.
Series
Series S
These grasses should
not wear
be confusedin
withTable
more persistent
standard
perennial
ryegrass
performance
under
sports
maintenance
and
S1.diploid perennial ryegrass that are more
Sports Uses (Mown at 25mm)
Sports
Uses
commonly
used (Mown
in sports at
turf25mm)
mixtures. In like-for-like comparisons, the traditional diploid grasses have
greater wear tolerance and produce a more attractive sward. However, the tetraploid grasses have
The results are shown in Figure 1 below.
characteristics that can be exploited alongside traditional grasses. The main benefits are quicker
germination and establishment in cool conditions and increased seedling vigour. Once established, they
Table S1
also tend
to maintain growth longer than diploid cultivars as temperatures fall in the winter. This allows
Table
S1s
Perennial ryegrass (Lolium perenne)
Resistance
to Red
thread
-5.6
5.3
6.6
6.3
6.7
5.7
5.9
6.2
5.2
6.4
6.4
6.8
5.6
5.8
5.3
5.9
6.6
6.5
6.3
5.9
6.7
6.8
5.7
7.4
5.9
4.6
6.2
7.4
5.2
5.6
6.4
6.0
6.4
6.3
6.8
Winter
greenness
Summer
greenness
UK Agent
Winter
Summer
greenness
greenness
Summer
greenness
UK Agent
7.5
7.7
6.1
6.7
4.9
6.2
6.3
6.2
6.2
6.3
5.5
5.7
6.0
5.0
5.3
6.7
4.8
4.9
5.8
6.2
6.8
6.3
5.4
6.2
6.2
6.1
6.3
5.9
5.5
7.0
5.7
7.0
6.0
5.9
5.0
6.4
5.3
6.7
DLF/JNS/TG
DLF/JNS
DLF
DLF/TG
RT/TG
BAR
BAR
G
DLF/JNS
DSV
G
DLF
DLF
DLF/JNS
DLF
LMG
DLF/TG
RT/TG
LMG
BAR
BAR
G
DLF
DLF/JNS
DLF
DSV
DLF
G
DLF
DLF
Agent
7.3
7.1
DLF/JNS
RT/TG
Agent
5.2
5.2
4.9
4.9
4.7
4.9
6.6
4.9
6.1
5.5
4.5
5.4
5.2
7.1
5.2
6.9
4.9
6.1
4.9
6.6
4.7
6.3
4.9
6.5
6.6
6.4
4.9
6.1
7.1
5.5
5.8
4.5
6.2
5.4
7.8
7.1
Summer
greenness
6.1
6.0
Winter
greenness
Fineness
of leaf
5.3
7.7
6.6
7.9
7.5
7.4
7.7
8.2
7.1
7.8
6.3
6.9
5.9
7.7
6.3
6.6
6.9
7.9
5.2
7.5
6.9
7.4
6.6
7.7
8.0
8.2
7.4
7.1
5.7
7.8
5.7
6.3
6.2
6.9
5.0
5.9
Fineness
of leaf
Recovery
Shoot
density
Shoot
density
6.2
6.1
6.2
6.8
5.5
7.3
7.5
7.4
7.5
7.9
7.3
7.4
7.4
7.5
7.2
7.3
7.3
7.3
6.8
7.7
7.2
7.4
7.3
7.4
7.5
7.2
7.4 (Poa
7.3pratensis)
7.4
7.4
meadow-grass
7.2
7.3
7.2
7.4
7.7
7.1
7.2
7.1
6.9
7.7
7.0
7.2
7.1
7.4
7.8
7.1
7.1
7.1
6.4
7.7
6.9
7.2
7.0
7.5
6.7
6.7
7.1
6.9
7.1
6.8
6.7
6.9
6.8
6.1
6.1
7.3
7.5
7.4
7.5
7.9
6.6
6.9
6.7
6.3
6.8
7.3
7.4
7.4
7.5
7.2
6.6
6.6
6.6
6.1
6.9
7.3
7.3
7.3
6.8
7.7
6.5
6.6
6.6
6.9
6.2
7.2
7.4
7.3
7.4
7.5
6.3
6.6
6.5
6.0
7.0
7.2
7.4
7.3
7.4
7.4
6.3
6.5
6.4
6.4
6.6
7.2
7.3
7.2
7.4
7.7
6.2
6.5
6.4
6.6
6.7
7.1
7.2
7.1
6.9
7.7
6.3
6.3
6.3
6.1
6.8
7.0
7.2
7.1
7.4
7.8
6.2
6.3
6.3
6.0
6.3
7.1
7.1
7.1
6.4
7.7
6.2
6.1
6.2
5.6
6.1
6.9
7.2
7.0
7.5
6.7
5.6
5.7
5.7
5.8
6.1
6.7
7.1
6.9
7.1
6.8
4.8
4.7
4.7
4.7
4.6
6.7
6.9
6.8
6.1
6.1
Recovery
Fabian
Sombrero
Julius
Harmonie
Table
S2
Greenplay
Bariris
Smooth-stalked
Barhelene
Joker
Limousine
Linares
Julia
Lincolnshire
Cultivar
Panduro
Sombrero
Mozart 1
Julius
Yvette
Harmonie
Broadway
Greenplay
Cocktail
Bariris
Touche
Barhelene
Parsifal
Joker
Aramintha (LA)
Limousine
Colonia (LA)
Linares
Miracle
Julia
Conni
Lincolnshire
Evora
Panduro
Cleanness
of cut
3.8
5.0
Resistance
to Rust
Fineness
of leaf
4.7
5.3
Mean
Double
Tetragreen
New
Cultivars
Cultivar
Fineness
of leaf
Shoot
density
Shoot
density
4.3
4.1
Smooth-stalked meadow-grass (Poa pratensis)
Cultivar
Cleanness
Resistance
of cut
to Rust
Resistance
to Red
Winter
greenness thread
Recovery
Recovery
5.2
4.9
Mean
Mean
5.0
4.7
Visual
merit
5.5
5.0
Table S2
Mean
Figure 1: Table S1 and Table S1s from Turfgrass Seed 2015.
Visual
merit
DLF/JNS
BAR
DLF/JNS/TG
DLF/JNS
DSV
BAR
DSV
G
LMG
LMG
DLF/JNS
RT/TG
DSV
RT/TG
G
G/CARN
G/CARN
G
LMG
BAR
DLF/TG
BAR
DLF/JNS
G/CARN
LMG
DSV
DLF
DLF/DSV
DLF/LMG
LMG
G
BAR
BAR
RT/TG
G
SUT/TG
DLF/JNS/TG
BAR
RT/TG
DLF/TG
DLF
Visual
merit
5.3
7.4
6.1
6.4
5.6
7.5
5.9
5.4
6.3
6.2
5.4
5.4
5.3
5.6
6.1
6.6
5.9
5.7
5.4
5.2
5.5
5.7
6.3
5.8
6.0
5.2
5.9
5.6
6.0
5.7
6.3
5.5
6.4
6.3
5.3
6.1
5.9
6.5
5.3
5.7
6.1
Visual
merit
5.2
5.6
5.6
6.0
5.4
6.1
5.7
4.9
5.4
5.1
4.9
4.9
5.3
5.1
5.1
5.4
6.0
4.7
5.1
4.2
5.7
5.1
6.0
6.0
5.5
5.3
5.7
5.4
5.5
5.4
5.9
6.1
5.4
5.6
5.1
5.7
5.4
5.1
4.9
5.5
5.8
Live
ground
cover
2.8
5.7
5.4
6.4
5.7
4.3
6.1
6.4
5.9
5.5
4.3
7.4
5.0
5.4
5.7
5.3
6.2
5.2
6.9
6.7
5.3
5.8
4.1
7.5
6.1
5.5
6.0
5.2
5.9
6.0
5.1
5.5
5.3
-
Live
ground
cover
7.5
4.3
5.5
7.2
7.0
7.0
8.0
4.4
4.4
6.5
5.0
5.9
0.0
7.3
7.1
5.8
6.2
5.6
5.3
5.2
6.5
6.3
6.2
7.8
4.8
7.3
6.4
-
Live
ground
cover
6.8
7.1
6.9
8.6
7.1
7.5
7.2
7.3
6.8
6.9
8.3
6.5
7.1
7.3
6.7
7.1
7.3
6.7
6.7
7.5
6.5
6.8
6.0
6.8
8.1
6.6
6.8
7.6
6.5
7.6
6.3
6.3
6.2
6.9
7.3
6.6
7.9
8.3
7.3
5.3
7.4
Tetraploid cultivars of perennial ryegrass are starting to be used in specialist seed mixtures for sports uses.
These grasses should not be confused with more persistent diploid perennial ryegrass that are more
commonly used in sports turf mixtures. In like-for-like comparisons, the traditional diploid grasses have
Cultivar
greater wear tolerance and produce a more attractive sward. However, the tetraploid grasses have
Double
5.5
5.0
5.2
4.3
4.7
3.8
6.1
7.8
7.3
7.5 DLF/JNS
characteristics that can be exploited alongside traditional grasses. The main benefits are quicker
Tetragreen
5.0
4.7
4.9
4.1
5.3
5.0
6.0
7.1
7.1
7.7 RT/TG
germination and establishment in cool conditions and increased seedling vigour. Once established, they
Newtend
Cultivars
also
to maintain growth longer than diploid cultivars as temperatures fall in the winter. This allows
Fabiangrasses to replace lost grass
6.2 cover
6.1 during
6.2 winter
6.8 wear.
5.5 The
5.3ratings
- presented
6.1
6.7 DLF/JNS/TG
these
are comparable
with
those given for diploid perennial ryegrass cultivars in Table S1.
Live
ground
cover
8.0
8.1
7.6
8.2
8.2
8.0
8.0
7.9
7.6
7.7
7.7
7.5
7.2
7.2
7.4
7.4
7.1
7.4
7.0
7.7
7.3
6.9
6.0
6.7
7.8
7.1
7.0
7.0
7.0
7.6
6.7
7.0
7.3
7.1
7.5
6.6
7.4
7.6
6.4
5.0
7.4
UK Agent
7.7
6.7
7.6
7.6
7.3
6.8
7.7
6.7
7.7
7.3
6.5
7.0
6.6
7.2
7.3
7.6
7.6
7.6
7.4
7.0
6.9
7.8
7.6
7.4
6.9
6.8
7.2
7.9
7.8
6.6
7.6
6.8
6.3
6.7
6.6
6.5
6.8
6.0
6.5
6.6
6.7
Summer
greenness
Fineness
of leaf
8.1
8.1
8.1
8.1
8.1
8.0
7.9
7.8
7.7
7.6
7.6
7.6
7.5
7.5
7.4
7.4
7.4
7.4
7.4
7.3
7.3
7.3
7.3
7.3
7.2
7.2
7.2
7.2
7.2
7.1
7.1
7.1
7.0
7.0
7.0
6.9
6.9
6.8
6.8
6.8
6.8
Winter
greenness
Shoot
density
8.1
8.0
8.0
8.2
8.0
8.0
8.0
7.8
7.7
7.7
7.8
7.5
7.5
7.6
7.4
7.5
7.6
7.6
7.4
7.4
7.4
7.3
7.3
7.5
7.3
7.2
7.2
7.4
7.1
7.3
7.2
7.1
7.0
7.1
7.1
7.0
6.9
6.9
6.9
6.9
6.9
Cleanness
of cut
Recovery
8.2
8.1
8.1
8.0
8.1
8.1
7.9
7.8
7.7
7.6
7.5
7.8
7.5
7.3
7.4
7.3
7.2
7.1
7.3
7.3
7.3
7.3
7.3
7.1
7.2
7.2
7.2
7.1
7.2
7.0
6.9
7.0
7.1
6.9
6.8
6.9
6.8
6.8
6.8
6.8
6.8
Resistance
to Red
thread
Mean
Eurodiamond
Barorlando
Columbine
Monroe
EuroCordus
Barcristalla
Eurosport
Eugenius
Madrid
Cyrena
Chardin
Poseidon
Shorty
Duparc
Promotor
Calico
Cadix
Vesuvius
Nagano
Barolympic
Berlioz 1
Bareuro
Bizet 1
Carnac
Alison (LA)
Beckham
Florianne
Ligala
Himalaya
Melbourne
Vitellius
Romance
Barillion
Hayley (LA)
Lucius
Greenfair
Clementine
Barsignum
Mercitwo
Hugo 1
Shania (LA)
Visual
merit
Cultivar
these grasses to replace lost grass cover during winter wear. The ratings presented are comparable with
Tetraploid
ryegrasses
those given for diploid perennial ryegrass cultivars in Table S1.
Live
ground
cover
Sports
Sports
Tetraploids are often marketed with claims of improved tolerance to various stress factors (drought and disease are the
most plausible), but in a winter sports pitch environment, theSeries
predominant
stress factor is of course WEAR.
S
Contact your local distributor | 01359 272000 | barenbrug.co.uk | info@baruk.co.uk
FACTfile
Find out more about grass with our FACTfiles.
Grass Experts Since 1904
Tetraploid Perennial Ryegrasses
Not only are the scores for “Live ground cover” and “Visual
merit” particularly poor, but interestingly “Recovery”
is actually significantly worse than standard diploid
ryegrasses. “Recovery” in the BSPB/STRI Turfgrass Seed
trials is actually scored as growth AFTER wear has finished
i.e. in June & July, which would even contradict the claim
that these tetraploid varieties grow faster than their diploid
counterparts.
Another disadvantage of tetraploids is their seed size;
roughly double that of a standard diploid. Twice as much
DNA in each cell has to go somewhere (as can be seen in
Figure 2), so seeding rates must be increased (along with
budgets!) to sow the same number of seeds.
This is not to say that tetraploids have no place for amenity
use. As breeding continues to progress with these types, Figure 2: The difference in seed size between diploid and tetraploid
finer-leaved “dwarf” cultivars may become available that perennial ryegrasses.
offer benefits to end-users.
Currently though, the inherent disadvantages of available varieties strongly out-weigh the positives.
Comparisons
Current tetraploid cultivars are being marketed as alternatives to amenity annual ryegrasses, which have recently been
used with much success for overseeding and renovation in unseasonable times of the year.
Tetraploids are naturally fast growers, but the ability to germinate at temperatues as low as 3.5ºC and speed of
establishment of annual cultivars like 4IR-1 in BAR 50 SOS is still unrivalled in laboratory testing
(see Figure 3).
Amenity annual ryegrasses therefore remain the best option for quick, short-term solutions to specific problem areas.
They may be short-lived, but so are the current tetraploids under wear and mowing regimes!
Variety
Germination % after 21 days at low temperature
Tetraploid ryegrass
Tetragreen (DLF)
37%
Double (DLF)
57%
Annual ryegrass
SOS (4IR-1)
76%
SOS (future variety)
84%
Figure 3: Results from cool temperature germination trial. Results after 21 days (10
days at 40ºC, 9 days at 60ºC, 2 days at 100ºC) show amenity annual cultivars offer
faster germination than tetraploid alternatives.
Contact your local distributor | 01359 272000 | barenbrug.co.uk | info@baruk.co.uk