scholarly journals Development of white clover (Trifolium repens L.) cultivar Grasslands Challenge (G23)

Author(s):  
B.M. Cooper ◽  
P.T.P. Clifford ◽  
W.M. Williams

Grasslands Challenge (Trifolium repens L.) white clover was developed to incorporate potential growth benefits, and disease resistance, in two double cross hybrids (Mediterranean × New Zealand) identified in evaluations at Kaikohe. Thirty-three elite selections of hybrids and New Zealand material were polycrossed for seed production. Progeny testing resulted in 27 parental lines with improved resistance to leaf disease and stem nematode (Ditylenchus dipsaci) relative to Grasslands Pitau. Testing of the maternal lines for seedling characteristics resulted in the deletion of one parent. A bulk line was evaluated in mini plots, and a hill country grazing trial, and showed improved growth to the control. In a grazing trial conducted in the Manawatu, Challenge showed outstanding winter production. The selection has a high stolon density in combination with a medium to large leaf size. This will allow Challenge to recover quicker from drought stress and grazing pressure. The plant type and early results indicate Challenge will be best suited to a rotational grazing management, particularly in regions where significant cool-season growth occurs. Plant Variety Rights were granted in 1997, and commercial seed should be available in 1998. Keywords: Grasslands Challenge, leaf disease, Mediterranean hybrids, stem nematode, Trifolium repens

1996 ◽  
Vol 6 ◽  
pp. 7-14
Author(s):  
R.D.J. Mather ◽  
D.T. Melhuish ◽  
M. Herlihy

White clover (Trifolium repens L.) is the dominant legume of temperate pastures, having been improved by breeding since the 1930s. The 1994 OECD Register lists 93 cultivars, with a further 25-30 cultivars also known to commerce. Therefore, in excess of 100 cultivars are available to fulfil a world annual market of 8500-10,500 MT. Globally, New Zealand is the major white clover production region, providing 50- 55% of the seed. Other key production regions are Denmark, USA and South America. Consumption of white clover has been relatively static for some time, ranging from 8000-10,000 MT per annum. Between 55-60% of the seed is used in the northern hemisphere (approx. 40% by Western Europe - UK, France, Germany). USA, South America and New Zealand all consume similar tonnages annually (approx. 1000-2000 MT each) with smaller tonnages used in Australia. One cultivar, Grasslands Huia, has dominated the world white clover seed market for many years and it still remains the world's major cultivar by volume. However, in the last 10 years its position has come under increasing pressure from New Zealand and international proprietary cultivars. Eventually proprietary cultivars with improved agronomic performance will supersede the consumption of commodity/public white clovers in those countries where national listing is required to obtain release and recommended listing is need to ensure successful marketing. Despite this, Grasslands Huia will continue for many years to play a major role in supplying markets where national listing is not a prerequisite to release and price is a major factor in purchase decisions. Keywords: commodity cultivar, global market, Grasslands Huia, leaf size, market share, production trends, proprietary cultivar, seed industry, Trifolium repens L., white clover


2007 ◽  
Vol 47 (1) ◽  
pp. 110 ◽  
Author(s):  
J. F. Ayres ◽  
J. R. Caradus ◽  
R. D. Murison ◽  
L. A. Lane ◽  
D. R. Woodfield

A breeding project has developed a new synthetic white clover (Trifolium repens L.) cultivar, Grasslands Trophy, that possesses tolerance of summer moisture stress in dryland pasture environments in the 850–1250 mm average annual rainfall temperate perennial pasture zone in eastern Australia. The breeding strategy used to develop Grasslands Trophy was an in situ breeding cycle for: (i) identifying and selecting superior genotypes, (ii) crossing elite germplasm and (iii) progeny testing derived breeding lines for the expression of key agronomic and grazing value traits. The primary selection criteria were early vigour, herbage yield, persistence and seed yield potential. Parental selection was also applied for seed yield, uniformity of leaf size, uniform flowering pattern and freedom from disease and virus symptoms. Grasslands Trophy is medium–large in leaf size with stable leaf size, combines intermediate stolon density with intermediate stolon thickness, and expresses high stolon survival and strong autumn regrowth following summer moisture stress. Grasslands Trophy has mid-season flowering maturity, intensive flowering prolificacy and high seed yield capability. Agronomic results from trials in northern New South Wales and New Zealand indicate that Grasslands Trophy has broad adaptation, expresses high summer and winter growth activity, and is reliably persistent for at least 4 years.


1988 ◽  
Vol 110 (1) ◽  
pp. 145-154 ◽  
Author(s):  
R. Cook ◽  
D. R. Evans

SummaryThe expression of symptoms of stem nematode reproduction on a total of 53 white clovers (26 cultivars, 14 genepools and 13 introductions from plant collections) was studied in a series of field and glasshouse experiments. Seedlings or stolon-tip cuttings were inoculated with nematodes and the clovers classified by the proportion of plants which developed symptoms. Significant differences were found between varieties although in each test the majority was intermediate between more resistant and susceptible extremes. There was significant positive correlation between tests, in spite of different inoculation methods and different average levels of susceptibility. Very large-leaved cv. Aran was more resistant than most other clovers tested, and small-leaved cv. S. 184 was more susceptible. There was no general correlation of leaf size with reaction to stemnematode. Small-leaved cv. Pronitro was also resistant while several large-leaved cultivars were susceptible. In observations of plants exposed to nematodes over a long period, either by sequential inoculations or through perpetuating latent infections, apparently resistant plants eventually succumbed and supported nematode reproduction. It has not been determined whether this was because selection for virulence in the nematodes had occurred.


Author(s):  
J. Van den Bosch ◽  
I.K. Black ◽  
G.R. Cousins ◽  
D.R. Woodfield

Drought-stress limits white clover (Trifolium repens L.) persistence in many New Zealand regions. As a component of breeding for enhanced drought tolerance, 8 selection groups (110 lines in total) of white clover were evaluated in the Wairarapa over a 2-year period. The selection groups included Australian white clover ecotypes, selections from New Zealand dryland populations, root morphology selections, pre-release selections from New Zealand breeding programmes, and existing overseas and New Zealand cultivars. The selection groups derived from New Zealand dryland populations had the highest forage yield and plant survival, 21 of the 24 individual lines with >30% plant survival coming from these groups. Groups containing Australian ecotypes and overseas cultivars had the lowest forage yield and plant survival. Selections for root morphology per se were lower yielding and less persistent than selections made from New Zealand dryland populations evaluated in drought-prone environments. However, some improvements in forage yield and persistence were observed through selecting for root morphology after screening the same New Zealand dryland populations in a drought-prone North Canterbury site. Keywords: drought tolerance, plant breeding, root morphology, Trifolium repens


1997 ◽  
Vol 37 (2) ◽  
pp. 159 ◽  
Author(s):  
S. G. Clark ◽  
M. J. McFadden

Summary. The herbage yield, stolon characteristics and soil seed reserves of a diverse range of white clover (Trifolium repens L.) cultivars were studied at Hamilton in south-western Victoria. The cultivars were sown with perennial grass (Phalaris aquatica L.) and the pasture was rotationally grazed by sheep. The aim of the study was to identify white clover types which would persist under sheep grazing. The widely used cultivar, Haifa, fails to persist in this environment. Cultivars were divided into 3 groups depending on leaf size (range 2.5–13.0 cm2). Large-leaved cultivars were the most productive in the first year of the experiment but by year 3 some of the intermediate leaf-size cultivars were the most productive. Haifa (large leaved) was particularly unproductive in the third year compared with other large and intermediate leaf-size cultivars. Stolon characteristics were measured in early spring 1987, mid summer 1988 and early autumn 1988. Total stolon yield on each occasion was 0.46–0.99, 0.65–1.68 and 0.05–0.25 t DM/ha respectively. Intermediate leaf- size cultivars tended to have the highest stolon yields on each occasion. Stolon yield declined at the same rate (mean 87%; range 81–92%) in all cultivars between the second and third sampling date indicating that there is no variation in the cultivars’ ability to survive the summer drought period. Although seed reserves for most cultivars were high at the end of the experiment (range 11–130 kg/ha) no seedling recruitment was observed and seed is thought to play no role in sward survival in this environment. Plant breeders developing white clover cultivars for this environment should concentrate on maximising stolon yield at the beginning and end of the summer drought period (January–mid March). Intermediate leaf-size genotypes are likely to provide the best combination of stolon and herbage yield. Grazing management should also aim to maximise stolon yield at these critical times. The use of large-leaved, non-stoloniferous cultivars should be discouraged by advisers as they are not suited to this marginal environment under sheep grazing.


Author(s):  
K.H. Widdup

White clover populations from Europe and New Zealand together with ecotypes collected from old pastures in Southland-Otago were evaluated as spaced plants at Gore. Plants were screened for herbage production and morphological and flowering characteristics. The Southland ecotypes and North Island hill country material are adapted to active growth in spring and summer. Their dense growth habit ensures continued production of branched stolons from nodal meristems which is necessary for high clover yield and persistence under intensive sheep grazing. In this region flowering characteristics are unimportant in relation to agronomic performance. Some largerleaved Huia and French lines have high-yielding features which are evident during autumn under lenient grazing. Hybrids between superior plants showing adaptive and high yie!ding features are being screened in order to select new types with the desired characteristics. Keywords: White clover, Trifolium repens L., plant breeding, southern region, ecotypes, growth, morphology.


2016 ◽  
Vol 67 (8) ◽  
pp. 897 ◽  
Author(s):  
M. Z. Z. Jahufer ◽  
J. L. Ford ◽  
D. R. W. Woodfield ◽  
B. A. Barrett

Optimal evaluation and use of introduced germplasm for species improvement is an ongoing challenge. Research was conducted to survey a select set of introduced white clover (Trifolium repens L.) germplasm from broad geographic origins to assess their genetic potential, based on F1 crosses to elite New Zealand cultivars. The bulk progeny generated from test crosses to Grasslands cultivars Demand, Sustain and Kopu II were evaluated at Palmerston North under rotational grazing by sheep. The replicated trial consisted of the 26 germplasm accessions, three cultivars used as maternal parents, and 78 F1 bulk progeny breeding lines. Three morphological traits and estimated seasonal dry matter yield were measured over four years. Significant (P < 0.05) genotypic variation was observed for all these traits among the parents and F1 progeny lines. F1 progeny lines with traits values greater than the cultivars were identified. Significant (P < 0.05) genotype-by-season (σ2gs) and genotype-by-year (σ2gy) interactions were estimated for dry matter yield. Principle component analysis of the F1 progeny-by-trait BLUP matrix identified 16 elite progeny lines with mean seasonal dry matter yield equal to or higher than the cultivars. Half of the lines had Demand as the cultivar parent, while only three had Kopu II as a parent. Fourteen of these progeny lines were derived from crosses to Australasian adapted germplasm. This study indicated that choice of adapted cultivar with which to cross is important, and introduced germplasm from Australasia is a valuable source of adaptive variation in these F1 progeny. More complex approaches may be needed to identify and use adaptive allelic variation from germplasm sources beyond Australasia.


1989 ◽  
Vol 67 (8) ◽  
pp. 2297-2301 ◽  
Author(s):  
Joanna Fraser

Some characteristics of seven populations of naturalized white clover (Trifolium repens L.) from native pastures in Nova Scotia, Prince Edward Island, and New Brunswick were investigated. Nine vegetative characters were measured on 16- to 18-week-old plants, and within and between population differences determined for cyanogenesis. Variation was observed between and within populations for all measured characteristics. Leaf marks were predominately the central V-shaped chevron; one population had plants without the chevron. Relative leaf size (length × width) ranged from 145 to 784 mm2. Hydrogen cyanide concentrations in leaf laminae were lower in cyanogenic (AcLi) and glucosidic (Acli) genotypes than enzymatic (acLi) genotypes. HCN concentrations in genotypes varied between and within populations. A population from Charlottetown, Prince Edward Island, had several desirable agronomic features, e.g., larger leaves, longer petioles, and thicker stolons than other populations, and could be used in a breeding programme for improved winter-hardy white clover varieties suited for rotational grazing and silage in Atlantic Canada.


Author(s):  
D.R. Woodfield ◽  
J.R. Caradus

Better persistence and reliability of white clover (Trifolium repens L.) is critical in achieving a more competitive New Zealand farming industry. To persist, white clover must establish well and withstand the accumulated stresses of competition from associated grasses, grazing, variable soil fertility, drought, plus pest and disease pressure. These factors vary markedly with environment and farming system, making the choice of appropriate grazing management, plant nutrition, companion species and cultivar difficult. White clover is particularly vulnerable to mismanagement and environmental stresses during spring when plant size is at its smallest. This vulnerability is further compounded by the current trend in dairying to apply high rates of nitrogen (N) which favours grass growth more than clover growth. A faster grazing rotation and/or higher stocking rates can offset the adverse effects of N on white clover by utilising the additional grass produced and reducing competition for light. Irrespective of N inputs, frequent defoliation during spring favours white clover persistence by increasing grass tiller density, resulting in better ground cover and in lower soil surface temperatures in summer. There is a threshold above which the density of associated grass suppresses clover growth. This is most prevalent in swards containing browntop, cocksfoot and kikuyu, which are more competitive against white clover than tall fescue, timothy and perennial ryegrass. Plant breeding efforts to improve persistence concentrate on increasing the rate of stolon formation and decreasing the rate of stolon death. These efforts include selecting genotypes that have better spread and persistence in association with different grasses, and genotypes that continue to grow with lower inputs of phosphate. Changes in root morphology have enhanced persistence under moderate drought stress, while significant improvements in resistance to clover cyst nematode, root-knot nematode and clover flea offer real hope in reducing the impact of these pests. Developing cultivars with higher stolon growing point densities at a particular leaf size should improve persistence while maintaining the greater yield potential. Keywords: climatic stresses, competition, diseases, grazing management, pests, plant breeding, plant nutrition, Trifolium repens L.


1998 ◽  
Vol 35 (3) ◽  
pp. 419-427 ◽  
Author(s):  
D.P. Malinowski ◽  
D.P. Belesky ◽  
J. Fedders

Sign in / Sign up

Export Citation Format

Share Document