Tetraploid perennial ryegrasses
Transcription
Tetraploid perennial ryegrasses
FACTfile Grass Experts Since 1904 Find out more about grass with our FACTfiles. 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 | [email protected] 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 | [email protected]