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1
Eden, T. M., P. J. Gerard, D. J. Wilson e N. L. Bell. "Effects of invertebrate pests on white and annual clovers in dryland soil". New Zealand Plant Protection 63 (1 agosto 2010): 235–40. http://dx.doi.org/10.30843/nzpp.2010.63.6574.
Testo completoAbstract (sommario):
Two experiments were carried out at Ruakura in soil taken from Whatawhata hill country pasture The relative susceptibility of several annual clovers (Trifolium spp) and perennial white clover (T repens) to slugs (Deroceras reticulatum) clover root weevil (Sitona lepidus) adults native crickets (Nemobius sp) or wheat bugs (Nysius huttoni) was tested by sowing seed of the clovers into separate rows in turf Susceptibility of clovers to clover cyst nematode (Heterodera trifolii) was tested by sowing each clover variety into Whatawhata soil inoculated with the nematode Plant growth was assessed in both experiments 4 weeks after sowing White clover was more susceptible to pests than the annual clovers with slugs and clover root weevil significantly reducing seedling survival and clover cyst nematode significantly reducing plant growth Subterranean clover (T subterraneum) cv Denmark was the least affected by pests showing no significant reduction in survival in the presence of slugs the most damaging pest and no significant decrease in plant root and shoot dry weight when exposed to nematodes
2
Rhodes, Ian, e K. Judith Webb. "Improvement of White Clover". Outlook on Agriculture 22, n. 3 (settembre 1993): 189–94. http://dx.doi.org/10.1177/003072709302200310.
Testo completoAbstract (sommario):
The need to reduce economic and environmental costs of livestock agriculture has led to a resurgence of interest in forage legumes, particularly white clover, However, despite a recognition of the benefits accruing from its high herbage quality and the nitrogen fixation from its symbiosis with the Rhizobium bacterium, the widespread use of white clover by farmers has been inhibited by several perceived Problems. Foremost amongst these have been a reputation for unreliable yield, lack of persistency under intensive grazing and propensity to cause bloat in cattle. Conventional breeding techniques coupled with extensive genetic resources and a growing understanding of the physiological basis of variation in yield and persistency have already resulted in the development of new reliably productive varieties. These varieties will provide a cornerstone for sustainable livestock agriculture in upland and lowland areas of the UK and Europe. The successful application of techniques of biotechnology to white clover has accelerated in recent years. An array of approaches is now available which will open the way for its genetic manipulation and subsequent germplasm enhancement. These approaches range from the routine maintenance and propagation of plants in vitro to the production of transgenic plants, and offer possibilities of altering radically the nature of white clover in the future.
3
Norton, M. R., e G. R. Johnstone. "Occurrence of alfalfa mosaic, clover yellow vein, subterranean clover red leaf, and white clover mosaic viruses in white clover throughout Australia". Australian Journal of Agricultural Research 49, n. 4 (1998): 723. http://dx.doi.org/10.1071/a97114.
Testo completoAbstract (sommario):
The levels of infection with 4 viruses in young white clover (Trifolium repens L.) plots sown in 1991 or 1992 were monitored at a total of 17 sites across the 6 States of Australia. Tests were undertaken for alfalfa mosaic (AMV), clover yellow vein (ClYVV), subterranean clover red leaf (SCRLV) (syn. soybean dwarf), and white clover mosaic (WClMV) viruses on field samples of 17 different cultivars, plus a local naturalised ecotype at each location, twice yearly over 3 years. The tests were undertaken using double antibody sandwich enzyme-linked immunosorbent assay (DASELISA). AMV and WClMV were the most common and widespread viruses. They infected plants atmany sites soon after establishment and then rapidly increased to high levels, occasionally exceeding 90% of plants. In contrast, at some sites, no infection with these viruses was detected. Analysis of the infection data at 4 sites, where significant spread of AMV occurred, indicated that the epidemics developed like compound interest models. Tests for SCRLV were done only in 1994 when moderate levels of infection were found at most southern, winter-rainfall dominant sites. The occurrence o fClYVV was sporadic and infection levels were always low.
4
POTTER, L. R. "The effects of white clover mosaic virus on vegetative growth and yield of clones of S.100 white clover". Plant Pathology 42, n. 5 (ottobre 1993): 797–805. http://dx.doi.org/10.1111/j.1365-3059.1993.tb01567.x.
Testo completo
5
Gerard, P. J., C. M. Ferguson e S. Van Amsterdam. "Comparison of New Zealand perennial clovers for resilience against common pasture pests". New Zealand Plant Protection 70 (25 luglio 2017): 241–49. http://dx.doi.org/10.30843/nzpp.2017.70.57.
Testo completoAbstract (sommario):
Clovers (Trifolium spp.) are vulnerable to a large number of invertebrate pests so pest resilience amongst 19 leading commercial or near release New Zealand-bred clover cultivars was compared. Laboratory feeding choice tests comparing foliage from the test clovers against Grasslands Kopu II as the standard confirmed that red clovers (T. pratense) were less preferred than white clovers (T. repens) by adult clover root weevil and clover flea. Grey field slug showed no preference between red and white clovers, with the white clover Grassland Prestige performing the best. Porina larvae had lowest weight gains on strawberry clover (T. fragiferum). Subsequent tests using neonate greenheaded leafroller larvae and an artificial diet made with freeze-dried foliage from cultivars in the most and least preferred subgroups indicated antifeedant compounds, rather than leaf morphology, are likely responsible for differences in feeding preferences between red and white clovers.
6
Francini, A., C. Nali, V. Picchi e G. Lorenzini. "Metabolic changes in white clover clones exposed to ozone". Environmental and Experimental Botany 60, n. 1 (maggio 2007): 11–19. http://dx.doi.org/10.1016/j.envexpbot.2006.06.004.
Testo completo
7
Belgrave, B. "Factors influencing farmer acceptance and uptake of new white clover cultivars". NZGA: Research and Practice Series 6 (1 gennaio 1996): 51–54. http://dx.doi.org/10.33584/rps.6.1995.3377.
Testo completoAbstract (sommario):
White clover is important to New Zealand pastoral farming yet uptake of new agronomically superior cultivars by farmers is slower than expected. Three main areas which explain why this is occurring are: 1. The need to demonstrate economic benefits due to superior agronomic performance of new cultivars to overcome barriers such as price and farmers satisfaction with existing products. 2. Farmers are influenced by advice of seed retailers/extension personnel, their knowledge of white clover cultivars, local research, and their economic situation. 3. White clover seed quantity and quality has been adversely affected by poor weather conditions at flowering and harvest over the last 3 or 4 years. Seed availability is also being affected by the cultivar change regulations and the changing land use patterns of Canterbury. The problem is magnified by the increasing number of white clovers being grown on a decreasing land base. For greater uptake and use of new white clovers, strategies that deal with all three areas are required. Keywords: buying decision, economic benefit, farmer use, seed availability, white clover
8
Gerard, Crush, e S. Rasmussen. "Formononetin in clovers as a feeding deterrent against clover root weevil". NZGA: Research and Practice Series 12 (1 gennaio 2006): 135–39. http://dx.doi.org/10.33584/rps.12.2006.3027.
Testo completoAbstract (sommario):
The effect of leaf feeding by adult clover root weevils on the isoflavonoid content of red and white clovers was investigated in a glasshouse experiment. Lines of both clovers previously selected for variation in formononetin content were used. A higher percentage of white clover leaves than red clover leaves were damaged by the weevils, and the high formononetin red clover was least readily eaten. The formononetin content of the white clovers did not differ between the selections, was much lower than in the red clovers, and did not change in response to weevil feeding. In both red clover lines, formononetin and biochaninA levels rose in response to weevil feeding, suggesting that both compounds have antifeedant properties against clover root weevil. Because high foliar levels of oestrogenic compounds like formononetin threaten fertility of grazing sheep it is concluded that plant breeding programmes should increase the levels of formononetin and/or biochaninA in clover roots to mitigate the impact of weevil larval feeding on roots and nodules.
9
ANNICCHIARICO, P., e E. PIANO. "Response of white clover genotypes to intergenotypic and interspecific interference". Journal of Agricultural Science 128, n. 4 (giugno 1997): 431–37. http://dx.doi.org/10.1017/s0021859697004334.
Testo completoAbstract (sommario):
Six white clover genotypes that were easily distinguishable from each other on the basis of leaf lamina marks and morphology were grown at Lodi, Italy, during 1990 and 1991 in dense swards, under field conditions and a mowing regime, as (i) pure stands, (ii) a complex mixture of all genotypes, (iii) binary mixtures of each genotype with each of two ryegrass varieties, and (iv) complex mixtures of all clover genotypes in binary association with each grass variety. The grass components were of known, different vigour. The study assessed both intergenotypic and interspecific interference and related dry matter yield responses to morpho-physiological traits of the clovers, and also determined whether a high level of morpho-physiological heterogeneity conferred a yield advantage on clover populations.Greater heterogeneity (i.e. a complex mixture of clover genotypes) did not produce higher clover yields either in the presence or absence of interspecific interference from grass; thus, the use of blends of varieties or the development of varieties with a fairly high degree of heterogeneity was not recommended for short-term meadows in environments with relatively low spatial and temporal variability. Interactions for yield occurred between clover genotypes and the presence or absence of intergenotypic interference (P<0·001), and between clover genotypes and the presence or absence of interspecific interference from the grass variety characterized by greater vigour and aggressiveness (P<0·01). The variance of the former interaction tended to be consistently larger than that of the latter interaction, indicating that competitive effects were greater between clovers than between the clover and grass components. A lower Spring [ratio ] Summer yield ratio and taller canopy tended to confer a competitive advantage under intergenotypic interference. Relatively better performance under interspecific interference was related to higher stolon density, suggesting that selection for this trait may increase the general ecological compatibility of large-leaved white clover types grown with vigorous grass companions.
10
Bouton, Joseph H., Brian Motes, Donald T. Wood, Ali Missaoui e Michael A. Trammell. "Registration of ‘Renovation’ White Clover". Journal of Plant Registrations 11, n. 3 (25 maggio 2017): 218–21. http://dx.doi.org/10.3198/jpr2016.11.0063crc.
Testo completo
11
Jahufer, M. Z. Z., J. L. Ford, K. H. Widdup, C. Harris, G. Cousins, J. F. Ayres, L. A. Lane et al. "Improving white clover for Australasia". Crop and Pasture Science 63, n. 9 (2012): 739. http://dx.doi.org/10.1071/cp12142.
Testo completoAbstract (sommario):
Improving the genetic merit of temperate forage legumes helps ensure profitability and sustainability of our Australasian pastoral industries. Today’s plant breeders are supported by a range of underpinning research activities including genetic resources exploration and enhancement, plant physiology, plant health, feed quality, agronomy, quantitative genetics and plant biotechnology; and have collaborative interfaces with animal and farm systems science. Lifting the rate of gain by integration of molecular tools, innovative breeding strategies, and new genetic resources is the major objective of our white clover breeding network. This paper, presented at the Australasian Grassland Association’s recent Legume Symposium, focuses on the key research and development achievements in white clover breeding for Australasia, and on the success and future of an Australasian collaboration to breed improved cultivars for the region’s temperate environments. The paper reports on successful developments in the areas of improving white clover root systems for phosphate uptake, pest tolerance, development of novel inter-specific hybrids and marker-aided breeding. The successful trans-Tasman collaboration in white clover breeding and future work is also discussed.
12
Bouton, J. H., D. R. Woodfield, J. R. Caradus e D. T. Wood. "Registration of ‘Durana’ White Clover". Crop Science 45, n. 2 (marzo 2005): 797. http://dx.doi.org/10.2135/cropsci2005.0797.
Testo completo
13
Bouton, J. H., D. R. Woodfield, J. R. Caradus e D. T. Wood. "Registration of ‘Patriot’ White Clover". Crop Science 45, n. 2 (marzo 2005): 797–98. http://dx.doi.org/10.2135/cropsci2005.0797a.
Testo completo
14
Park, C. Y., S. H. Lee, S. Lim, J. S. Moon e B. S. Kim. "First Report of White clover mosaic virus on White Clover (Trifolium repens) in Korea". Plant Disease 101, n. 8 (agosto 2017): 1559. http://dx.doi.org/10.1094/pdis-02-17-0256-pdn.
Testo completo
15
McLeish, L. J., G. N. Berg, J. M. Hinch, L. V. Nambiar e M. R. Norton. "Plant parasitic nematodes in white clover and soil from white clover pastures in Australia". Australian Journal of Experimental Agriculture 37, n. 1 (1997): 75. http://dx.doi.org/10.1071/ea96046.
Testo completoAbstract (sommario):
Summary. Seventeen sites, including locations in all the major white clover growing regions of Australia, were surveyed for the presence of plant parasitic nematodes in autumn and spring 1993. Trifolium repens L. cvv. Haifa and Irrigation, plus 1 other cultivar, were sampled at each site and nematodes extracted from roots, stems and soil. Thirteen genera of plant parasitic nematodes were detected. The clover cyst nematode, Heterodera trifolii, and root knot nematodes, Meloidogyne spp., were each recorded at over 75% of the sites. The most common genera of plant parasitic nematodes detected were Tylenchus, which was present at all sites, and Pratylenchus (root lesion nematode), which was present at all but 1 site. Other plant parasitic nematode genera found included Ditylenchus, Helicotylenchus and Paratylenchus. The widespread presence of nematodes in white clover pastures, and the high populations at some sites, suggest that they may be economically important to the Australian dairy industry.
16
Black, A. D., D. J. Moot e R. J. Lucas. "Seasonal growth and development of Caucasian and white clovers under irrigated and dryland conditions". NZGA: Research and Practice Series 11 (1 gennaio 2003): 81–89. http://dx.doi.org/10.33584/rps.11.2003.2992.
Testo completoAbstract (sommario):
Dry matter (DM) production of sown monocultures of Caucasian and white clovers was compared under irrigated and dryland (non-irrigated) conditions in their third year. Caucasian clover produced 11.9 t DM/ ha when irrigated and 9.4 t DM/ha under dryland conditions, and both treatments exceeded white clover by ~2.5 t DM/ha. This increase in yield reflected ~23 kg DM/ha/day higher production rates in spring and summer. During this period, production rates of irrigated treatments increased by 11 kg DM/ ha/day/oC for Caucasian compared with 8 kg DM/ha/ day/oC for white clover as mean daily air temperature increased from 8-16 oC. In late summer/autumn, production rates of Caucasian clover decreased more than white clover when air temperature dropped from 16-9 oC. Growth (photosynthesis) and development (leaf appearance) characteristics of each species were also examined. Leaf photosynthesis was ~6 ƒÊmol CO2/m2/ s higher for Caucasian than for white clover irrespective of measured air temperatures (7-28 oC) and soil moisture from 1.00-0.39 of water holding capacity (WHC, 512 mm to 1.5 m depth). Both clovers had similar ranges of optimum temperature (21-25 oC) and soil moisture (1.00-0.86 of WHC) for photosynthesis. These results could explain the observed higher production rates for Caucasian clover in spring and summer, under both irrigated and dryland conditions. Lower production rates of Caucasian clover in autumn may be attributed to a similar phyllochron (126 oCd), but higher base temperature (5 oC) than for white clover (1 oC), and hence a slower recovery to canopy closure post grazing. This study shows that Caucasian clover has potential to increase spring and summer legume production, in combination or as the sole legume species in both irrigated and dryland grass/clover pastures in lowland temperate environments of New Zealand. Key words: irrigation, photosynthesis, phyllochron, seasonal production, Trifolium ambiguum M. Bieb, T. repens
17
Van Den Bosch, J., C. F. Mercer e J. L. Grant. "Variation in white clover for resistance to clover cyst nematode". New Zealand Journal of Agricultural Research 40, n. 2 (gennaio 1997): 223–29. http://dx.doi.org/10.1080/00288233.1997.9513241.
Testo completo
18
Brock, J. L., M. G. Hyslop e K. H. Widdup. "A review of red and white clovers in the dryland environment". NZGA: Research and Practice Series 11 (1 gennaio 2003): 101–7. http://dx.doi.org/10.33584/rps.11.2003.3001.
Testo completoAbstract (sommario):
Red and white clovers are best adapted to areas with good soil fertility and adequate soil moisture (750 mm annual rainfall), particularly over summer (150 mm), and are therefore restricted to small areas such as the more fertile valley floors and lower shady slopes in dryland environments. To extend their range and aid survival in dry environments, grazing management and cultivar selection are critical. Continual grazing (set stocking) during spring leads to a dense grass pasture, providing protection from desiccation for white clover stolons in the following summer. White clover cultivars have an inbuilt plasticity that allows morphological adaptation to changes in grazing management. For instance, set stocking in combination with a small-leafed cultivar results in a reduction of plant size but an increase in the stolon population, leading to better plant survival through drought periods. Where drought leads to stolon death, reseeding becomes a viable mechanism for clover persistence, and grazing management has a major influence on survival of new seedlings. For red clover, there is evidence that 'creeping' types survive better than 'crown' types in hill country, but the scope for extending red clover into drier areas is more limited. Key words: cultivars, drought, dryland, grazing management, morphological adaptation, persistence, red clover, reseeding, summer rainfall, Trifolium repens, T. pratense, white clover
19
Fraser, J., e H. T. Kunelius. "Influence of seeding time on the yield of white clover/orchardgrass mixtures in Atlantic Canada". Journal of Agricultural Science 120, n. 2 (aprile 1993): 197–203. http://dx.doi.org/10.1017/s0021859600074232.
Testo completoAbstract (sommario):
SUMMARYThe influence of four seeding times on herbage dry matter (DM) yields and clover content of white clover (Trifolium repens L.)/orchardgrass (Dactylis glomerata L.) mixtures was evaluated at Truro, Nova Scotia and Charlottetown, Prince Edward Island from 1985 to 1988. Sacramento, Sonja and Milkanova white clover/orchardgrass mixtures were assessed under simulated grazing (four or five harvests per year) over two production years at each location.Delaying seeding from May to August reduced total herbage DM yields significantly in the first production year, from 8·1 to 3·3 t/ha in Truro and from 11·0 to 7·2 t/ha in Charlottetown. Late seeding significantly reduced clover content in the herbage of the first two harvests in the first production year but, by the mid to late-season harvests, white clover content had increased to levels similar to those of the May seeding. Estimated white clover DM yields were highest in June, and dropped in the second production year at both locations. Sonja and Milkanova white clovers consistently outyielded Sacramento in herbage DM yields and clover content in both locations irrespective of seeding dates.
20
Caradus, J. R., D. R. Woodfield e A. V. Stewart. "Overview and vision for white clover". NZGA: Research and Practice Series 6 (1 gennaio 1996): 1–6. http://dx.doi.org/10.33584/rps.6.1995.3368.
Testo completoAbstract (sommario):
White clover (Trifolium repens L.) is the key to the international competitive advantage of New Zealand's pastoral industries, which are reliant on a cheap, high quality feed source. White clover benefits pastoral agriculture through its ability to fix nitrogen, its high nutritive value, its seasonal complementarity with grasses, and its ability to improve animal feed intake and utilisation rates. The annual financial contribution of white clover through fixed nitrogen, forage yield, seed production and honey production is estimated as $3.095 billion. The impact of white clover has resulted from understanding how it grows, and then developing appropriate management systems, fertiliser strategies, and improved cultivars. While the future of white clover as the legume base of our pasture is secure there are challenges and opportunities ahead. These include the increasing use of mineral nitrogen, competitiveness with high endophyte ryegrasses, filling gaps in our knowledge base, responding to industry signals, the advent of transgenic technologies, the removal of anti-quality characters particularly those associated with the incidence of bloat, and assuring that nitrogen fixation rates, in grazed pastures, increase as the yield potential of white clover is itself increased. Keywords: economic value, nitrogen fixation, nutritive quality, pastoral agriculture, white clover
21
MARSHALL, A. H., P. A. HOLLINGTON e D. H. HIDES. "Spring defoliation of white clover seed crops. 1. Inflorescence production of contrasting white clover cultivars". Grass and Forage Science 48, n. 3 (settembre 1993): 301–9. http://dx.doi.org/10.1111/j.1365-2494.1993.tb01863.x.
Testo completo
22
McCurdy, James D., J. Scott McElroy, Michael L. Flessner, Jared A. Hoyle e Ethan T. Parker. "Tolerance of Three Clovers (Trifoliumspp.) to Common Herbicides". Weed Technology 30, n. 2 (giugno 2016): 478–85. http://dx.doi.org/10.1614/wt-d-15-00062.1.
Testo completoAbstract (sommario):
Clover inclusion may increase the sustainability of certain low-maintenance turfgrasses. However, selective weed control within mixed turfgrass–clover swards proves problematic because of clover susceptibility to herbicides. Research was conducted to identify common turf herbicides that are tolerated by threeTrifoliumspecies, including white clover, ball clover, and small hop clover, within low-maintenance turfgrass. Leaf and flower density, as well as plant height, were measured 4 wk after treatment as indicators of clover response to 14 herbicides. The threeTrifoliumspp. were moderately tolerant of bentazon (< 35% decrease in leaf density, height, or flowering). Simazine was well tolerated by white clover (< 5% decrease in all response variables), yet moderate injury to ball clover and small hop clover was observed (> 32% decrease in leaf density and > 27% decrease in flower density). Pronamide was well tolerated by white and ball clovers, with no effect on measured response variables; however, pronamide decreased small hop clover height and flower density (38 and 42%, respectively). Imazethapyr and imazamox were moderately well tolerated by white clover and small hop clover (< 39% decrease by all response variables), yet ball clover may be more susceptible to these herbicides than was anticipated based on previously reported tolerance. The herbicides 2,4-DB, halosulfuron, and metribuzin were well tolerated by white clover, with no effect on measured response variables; however, results suggest ball and small hop clovers were less tolerant. Clopyralid, 2,4-D, glyphosate, imazaquin, metsulfuron-methyl, and nicosulfuron resulted in varying degrees of injury across clover species and response variables, but, in general, these herbicides may not be viable options when attempting to maintain any of the three clover species tested. Further research is needed to quantify long-term effects of herbicide application on sward composition and clover succession.
23
Peprah, Samuel, Enkhjargal Darambazar, Bill Biligetu, Kathy Larson, Alan Iwaasa, Daalkhaijav Damiran, Murillo Ceola Stefano Pereira e Herbert Lardner. "White Prairie Clover (Dalea candida Michx. ex Willd.) and Purple Prairie Clover (Dalea purpurea Vent.) in Binary Mixtures with Grass Species". Sustainable Agriculture Research 11, n. 2 (9 marzo 2022): 30. http://dx.doi.org/10.5539/sar.v11n2p30.
Testo completoAbstract (sommario):
Native forage legumes may have potential for summer/fall grazing in semiarid prairie regions in mixture with grasses. The objective of this study was to evaluate two native clovers in binary mixtures with the introduced grasses when harvested in July and September to simulate late summer or fall stockpile forage. Eight binary clover–grass mixtures were seeded in a split-plot design with 4 replications at Swift Current, Saskatchewan, Canada. Mixtures included (i) AC Antelope white prairie clover (WPC)-Admiral meadow bromegrass (MBG), (ii) WPC-AC Success hybrid bromegrass (HBG), (iii) WPC-Bozoisky Russian wildrye (RWR), (iv) WPC-TomRWR, (v) AC Lamour purple prairie clover (PPC)-AdmiralMBG, (vi) PPC-AC SuccessHBG, (vii) PPC-BozoiskyRWR, and (viii) PPC-TomRWR. Clover establishment differed (p = 0.03) in July where WPC had 77.8% greater proportion in mixture than PPC, although both clovers increased (p < 0.001) in September to similar legume proportions, 663.2 and 876.1 kg/ha, respectively. Clovers with bromegrasses produced 41.9% more forage dry matter yield in summer than clovers with Russian wildryes (p < 0.001), though the latter mixtures had slightly better nutritive value (avg. 7.0% vs. 5.2% crude protein (CP). Clover–MBG exhibited higher (53.6%) in vitro organic matter digestibility (IVOMD) than Clover–HBG (51.2%) (p = 0.04). Purple prairie clover with grass or both clovers in mixture with bromegrasses, produced adequate forage biomass for summer and fall grazing, except clovers with Bozoisky RWR, while clovers with both RWR cultivars had acceptable forage nutritive value for summer in this semiarid prairie region.
24
Williams, W. M. "Trifolium interspecific hybridisation: widening the white clover gene pool". Crop and Pasture Science 65, n. 11 (2014): 1091. http://dx.doi.org/10.1071/cp13294.
Testo completoAbstract (sommario):
White clover (Trifolium repens) is adapted to moist, fertile soils in temperate zones. Despite its heterozygous allotetraploid nature, it lacks useful genetic variation for survival and growth in semi-arid, infertile soils. Although white clover is apparently genetically isolated in nature, 11 other taxa have so far been found that can be artificially hybridised into the wider gene pool. These species range from annuals to long-lived, hardy perennials with adaptations to stress environments, and they potentially provide new traits for the breeding of more resilient varieties of white clover. The delineation of the secondary, tertiary and quaternary gene pools is described, along with a review of interspecific hybrids achieved to date. The results of large breeding programs to integrate traits from T. nigrescens and 4x T. ambiguum are reviewed, and schemes introduced for the use of T. uniflorum, T. occidentale, T. pallescens, 2x T. ambiguum and 6x T. ambiguum. Interspecific hybrid breeding of white clover has the potential to enable the development of resilient perennial clovers for seasonally dry, infertile grassland environments in many parts of the world.
25
Mccartin, John. "ALTERNATIVE ESTABLISHMENT STRATEGIES FOR WHITE CLOVER SEED PRODUCTION". NZGA: Research and Practice Series 2 (1 gennaio 1985): 33–35. http://dx.doi.org/10.33584/rps.2.1985.3305.
Testo completoAbstract (sommario):
Autumn sown white clover after wheat results in good white clover establishment and large areas can be sown. Direct drilling white clover into barley stubble in the autumn also gives very good white clover establishment. Other methods which include ryegrass and white clover sown together in autumn, sowing with autumn wheat, undersowing barley and processed peas in the spring and oversowing autumn wheat in the spring are less successful. Keywords: White clover, Trifolium repens,
26
E.V., Gorbkova. "The use of white clover in agriculture". Ekologiya i stroitelstvo 1 (2015): 19–22. http://dx.doi.org/10.35688/2413-8452-2015-01-005.
Testo completoAbstract (sommario):
The article considers problems of increase of efficiency of use of agricultural land. Summarized experimental data on cultivation of white clover in different countries. Recommendations on the improvement of soil fertility. Summarizes experimental data obtained during the research works on the study of white clover under irrigation for non-Chernozem zone, Moscow region on the production site «Dubna» in 2012–2014 Considered the agrotechnics of cultivation of white clover to obtain high-protein feed for livestock. It is noted that the white clover is a promising crop, contributes to the restoration of soil resources is used to produce low cost biological nitrogen needs irrigation. It is established that the maximum productivity is achieved clover 70...75 day from the date of sowing. Late sowing white clover adversely affects the growth and development of plants. To solve the fodder problem, it is recommended the advanced sowing of white clover, as in the context of irrigation, it is able to give good yields. It is noted that the clover well grown for silage, green manure, as feed additive in the form of hay. Perhaps the use of clover in crop rotation for conservation and reproduction of soil fertility. Clover is recommended to strengthen the slopes of roads and ditches for erosion control, as already in the first year of vegetation it forms a strong root system to 60 cm depth.
27
Cresswell, Ann. "White clover roots cause stolon burial". NZGA: Research and Practice Series 6 (1 gennaio 1996): 136–346. http://dx.doi.org/10.33584/rps.6.1995.3353.
Testo completoAbstract (sommario):
A large proportion of clover stolon in the field (20- 95%) is found below the soil surface (Hay 1983, Sackville Hamilton & Harper 1989). The proportion increases dramatically through the autumn and is reduced in spring. This pattern of burial has been attributed to earthworm casting and livestock trampling (Hay et al. 1987). In greenhouse experiments we observed that stolons were often held tightly to the soil surface and some nodes on mature stolons were beneath the surface. Three experiments designed to measure downward movement of stolons relative to the soil surface in controlled conditions without trampling or earthworm casting are described. Keywords: roots, stolon burial, Trifolium repens L.
28
Crush, J. R., e J. R. Caradus. "Increasing symbiotic potentials in white clover". NZGA: Research and Practice Series 6 (1 gennaio 1996): 91–94. http://dx.doi.org/10.33584/rps.6.1995.3363.
Testo completoAbstract (sommario):
Lines of white clover with higher and lower numbers of nodules were selected from a mutagenised Huia population, and seed was produced from a polycross of both lines. The progeny showed that the lines tended to have either more but smaller nodules, or fewer and larger nodules. In a further experiment, the line with fewer (larger average size) nodules, fixed more nitrogen (N) and grew bigger. Plants with fewer but larger nodules are a good model for efforts to increase the Nfixing capacity of white clover. An empirical screening method was used to obtain 15 genotypes that showed evidence of high mycotrophy. A second experiment confirmed that 5 of these genotypes gave abnormally high responses to mycorrhizal infection. Examination of the roots of these plants showed that the selections did not differ from their parent lines in terms of root length or root hair cylinder diameter. The results tend to confirm published work with spring wheat, which showed that land races and wild types respond more strongly to mycorrhizal infection than high yielding varieties do. Investigation of the mycorrhizal responses of clover ecotypes that are adapted to low phosphorus soils is a priority for future research. Keywords: mycorrhizas, nitrogen fixation, nodulation, symbioses, white clover
29
Mclaughlin, M. R., e G. A. Pederson. "Registration of PSVR1 White Clover Germplasm". Crop Science 40, n. 1 (gennaio 2000): 298–99. http://dx.doi.org/10.2135/cropsci2000.0002rgp.
Testo completo
30
Caradus, J. R. "World checklist of white clover varieties". New Zealand Journal of Experimental Agriculture 14, n. 2 (aprile 1986): 119–64. http://dx.doi.org/10.1080/03015521.1986.10426137.
Testo completo
31
THOMPSON, L. "Sites of photoperception in white clover". Grass and Forage Science 50, n. 3 (settembre 1995): 259–62. http://dx.doi.org/10.1111/j.1365-2494.1995.tb02321.x.
Testo completo
32
Kang, J. H., G. E. Brink e D. E. Rowe. "Seedling White Clover Response to Defoliation". Crop Science 35, n. 5 (settembre 1995): 1406–10. http://dx.doi.org/10.2135/cropsci1995.0011183x003500050024x.
Testo completo
33
Brink, G. E., e G. A. Pederson. "White Clover Response to Grazing Method". Agronomy Journal 85, n. 4 (luglio 1993): 791–94. http://dx.doi.org/10.2134/agronj1993.00021962008500040003x.
Testo completo
34
Barrett, B., A. Griffiths, M. Schreiber, N. Ellison, C. Mercer, J. Bouton, B. Ong et al. "A microsatellite map of white clover". Theoretical and Applied Genetics 109, n. 3 (22 aprile 2004): 596–608. http://dx.doi.org/10.1007/s00122-004-1658-0.
Testo completo
35
Collins, R. P., e I. Rhodes. "Stolon characteristics related to winter survival in white clover". Journal of Agricultural Science 124, n. 1 (febbraio 1995): 11–16. http://dx.doi.org/10.1017/s0021859600071197.
Testo completoAbstract (sommario):
SUMMARYChanges in the stolon carbohydrate contents (water-soluble and total non-structural) of four white clover populations were measured at the beginning and end of winter. Three of the populations were of Swiss origin - two of these were from high-altitude pastures, and the other from a valley location. Grasslands Huia was measured as a control variety. Levels of both types of carbohydrate declined during the winter in all populations. The Swiss populations from high altitudes contained the highest levels of both carbohydrate types.An artificial freezing test was carried out on stolon segments collected from a range of clover populations (including the two high-altitude Swiss clovers) growing in field plots in January, and values of ‘lethal dose 50’ (LD50) were calculated. The two Swiss populations had the lowest LD50 values, indicating a greater intrinsic tolerance to freezing in those plants than in the other populations (of lowland temperate origin).One of the Swiss populations, Ac3785, was grown under two temperature regimes and short daylength to determine whether its tolerance to freezing increased with time. Significant increases in tolerance occurred after 8 days at 2 °C, but plants grown at 8 °C showed no change in tolerance even after 30 days.The results suggest that (i) stolon carbohydrate content is an important factor in the overwintering of white clover, (ii) there is a considerable amount of genetic variation in cold tolerance within white clover, (iii) artificial freezing tests can provide a method of predicting the survival of clover stolons during winter and (iv) the cold hardiness of white clover increases with time spent at temperatures near 0 °C under short daylengths.
36
Gerard, P. J. "Nodule damage by clover root weevil larvae in white clover swards". New Zealand Plant Protection 55 (1 agosto 2002): 246–51. http://dx.doi.org/10.30843/nzpp.2002.55.3947.
Testo completoAbstract (sommario):
The impact of clover root weevil larval populations was assessed in pure swards of Grasslands Prestige and Grasslands Kopu white clover in a small plot trial Nodule damage was very evident and both cultivars showed significant increases in nodule damage and decreases in percent foliar nitrogen in November in response to increasing winter larval numbers Dry matter production of Kopu in November was related to foliar nitrogen levels
37
Martin, Pierre H., Bruce E. Coulman e Jean F. Peterson. "Genetics of Tolerance to White Clover Mosaic Virus in Red Clover". Crop Science 30, n. 6 (novembre 1990): 1191–94. http://dx.doi.org/10.2135/cropsci1990.0011183x003000060005x.
Testo completo
38
Høgh-Jensen, H., e J. K. Schjoerring. "Rhizodeposition of nitrogen by red clover, white clover and ryegrass leys". Soil Biology and Biochemistry 33, n. 4-5 (aprile 2001): 439–48. http://dx.doi.org/10.1016/s0038-0717(00)00183-8.
Testo completo
39
Potter, Daniel A., Carl T. Redmond, Timothy D. McNamara e Gregg C. Munshaw. "Dwarf White Clover Supports Pollinators, Augments Nitrogen in Clover–Turfgrass Lawns, and Suppresses Root-Feeding Grubs in Monoculture but Not in Mixed Swards". Sustainability 13, n. 21 (26 ottobre 2021): 11801. http://dx.doi.org/10.3390/su132111801.
Testo completoAbstract (sommario):
The runoff or leaching of nitrogen fertilizers from monoculture turfgrass lawns contri-butes to water pollution, and such lawns are susceptible to insect pests and provide few resources for pollinators. One approach to creating more sustainable lawns is to incorporate white clover (Trifolium repens L.), a nitrogen-fixing legume, into grass seed mixtures or existing turfgrass swards. “Dutch” white clover (DWC), a ubiquitous landrace, forms non-uniform clumps when intermixed with turfgrasses, thus it is often considered to be a lawn weed. Recently, several dwarf varieties of white clover have been selected for their small leaf size and low growth habit, allowing them to tolerate low mowing heights and blend better with grasses. To date, there have been no studies published on the entomological aspects of dwarf clover in pure stands or intermixed with turfgrass. We established field plots with combinations of DWC, two cultivars of dwarf clover, and tall fescue (Schedonorus arundinaceus (Schreb.) Dumort.) in monoculture or mixed swards, and compared the invertebrate communities therein. Predatory arthropods and earthworm numbers were similar in all plot types. The clover monocultures were resistant to white grubs, but the grub densities in the clover–tall fescue dicultures were similar to those found in the pure tall fescue swards. Dwarf clovers and DWC were similarly attractive to bees and supported similar bee assemblages. The tall fescue foliar N content was elevated 17–27% in the dicultures with clovers.
40
Hill, MJ. "Sward growth of monocultures and binary mixtures of phalaris, lucerne, white clover and subterranean clover under two defoliation regimes". Australian Journal of Experimental Agriculture 31, n. 1 (1991): 51. http://dx.doi.org/10.1071/ea9910051.
Testo completoAbstract (sommario):
Sirosa phalaris, WL5 15 lucerne, Haifa white clover and Seaton Park subterranean clover were grown in monocultures and binary mixtures on a cracking clay soil and cut at 4- and 8-week intervals over 3 growing seasons at Scone, New South Wales (32�S.). The plots were given supplementary irrigation between mid April and November to prevent water deficits. The deep-rooted perennials dominated mixtures under infrequent cutting, with cumulative dry matter yields for the growing season reaching 11 t/ha for lucerne-based mixtures. Frequent defoliation increased the contribution of the clovers in mixtures, and mixtures and monocultures containing clovers were more productive than other plots in winter, 1986. Frequent defoliation reduced the vigour and density of lucerne, resulting in balanced mixtures with phalaris and subterranean clover in the third year. Only lucerne plots contributed large amounts of dry matter yield (up to 4 t/ha) between December and April. Regeneration of subterranean clover from seedlings, and white clover from seedlings or stolons, was better in clover-only plots than in mixtures with phalaris. The growth of mixtures in response to mean daily air temperature in spring could be divided into 2 distinct patterns, with growth peaking at about 15�C for determinate (annual or dormant) mixtures, and at about 18�C for lucerne mixtures and pure white clover. In autumn, growth patterns were determined by the method of regeneration (i.e. by seedings or dormant crowns).
41
Ferguson, C. M., D. M. Barton e B. A. Philip. "Clover root weevil tolerance of clover cultivars". Journal of New Zealand Grasslands 78 (1 gennaio 2016): 197–202. http://dx.doi.org/10.33584/jnzg.2016.78.500.
Testo completoAbstract (sommario):
Clover root weevil arrived in New Zealand about 20 years ago causing major loss of productivity as it progressively spread across the whole country. It is now largely controlled by an introduced parasitic wasp biocontrol agent Microctonus aethiopoides (Irish ecotype). However, management of insect pests should not rely on a single mechanism and clovers resistant or tolerant to this weevil would be a useful augmentation for farmers to have. This investigation reports on the suitability of 22 clover cultivars to attack from the weevil. Results have shown that contrary to popular belief, red clovers are not universally less favourable to the weevil than white clovers and usefully, within both species cultivar differences point to the possibility of resistance to this pest. Keywords: Clover root weevil, Sitona obseletus, clover cultivars
42
Cosgrove, G. P., C. B. Anderson e R. H. Fletcher. "Do cattle exhibit a preference for white clover?" NZGA: Research and Practice Series 6 (1 gennaio 1996): 83–86. http://dx.doi.org/10.33584/rps.6.1995.3367.
Testo completoAbstract (sommario):
Attaining a predictable and stable composition of white clover in pasture is affected by selective grazing and inter-species plant competition. This paper reports an experiment which demonstrates that when given a free choice between monocultures of ryegrass and white clover, cattle did not selectively graze only clover but chose a mixed diet. Ten young heifers were stocked for 3 weeks on 2 ha, comprised of adjacent 1-ha monocultures of each of ryegrass and white clover. Animals were given 1 week to adjust to the spatial separation and then on 2 consecutive days in each of 2 consecutive weeks, cattle were observed at 10-minute intervals during daylight hours. Behaviour (grazing or not) and location (ryegrass or white clover) were recorded. This procedure was conducted in December, February and May to assess seasonal variation in the species preference. At each occasion cattle choose a mixed diet by eating both ryegrass and white clover, but their preference for white clover changed with season. In February they exhibited a partial preference for white clover, by spending approximately 65% of grazing time on white clover and 35% on ryegrass. In December and May the partial preference for white clover was lower, with cattle allocating approximately 47% of grazing time to white clover and 53% to ryegrass. Results are discussed in relation to the extent of preference for white clover when limitations to selection are removed and how this information could be used to enhance white clover proportion in the diet to better match animal preference. Keywords: diet selection, grazing behaviour, perennial ryegrass, preference, Trifolium repens L.
43
Woodfield, D. R., J. L. Ford e Mzz Jahufer Johnston. "New generation white clovers for United Kingdom farming systems". NZGA: Research and Practice Series 12 (1 gennaio 2006): 115–18. http://dx.doi.org/10.33584/rps.12.2006.3033.
Testo completoAbstract (sommario):
White clover is used worldwide to improve the nutritive value of pastures and is an increasingly important component of environmentally-sustainable grassland ecosystems. In 1991, a white clover breeding program involving two New Zealand companies (AgResearch and Midlands Seed) and a European company (Barenbrug), was initiated to develop new varieties for agricultural systems in the United Kingdom. This collaborative international program has been very successful with three improved varieties, Crusader, Barblanca and Makuri, being released and listed in the United Kingdom. The improved persistence and productivity of these varieties has enabled them to secure a significant share of the UK proprietary seed market. In particular, the medium-leaved Crusader produces at least 30% more DM than any other small or medium-leaved white clovers in UK Recommended List trials. Changes in agricultural subsidies within the EU Common Agricultural Policy and the growing pressure to use environmentally sustainable agricultural practices should increase demand for new generation white clover varieties that can maximise both pasture production and animal productivity.
44
Clark, D. A., e S. L. Harris. "White clover or nitrogen fertiliser for dairying?" NZGA: Research and Practice Series 6 (1 gennaio 1996): 107–14. http://dx.doi.org/10.33584/rps.6.1995.3348.
Testo completoAbstract (sommario):
Annual production in New Zealand dairy pastures is limited by nitrogen supply and therefore requires nitrogen fertiliser to increase annual pasture production. This paper summarises the advantages and disadvantages of clover nitrogen and fertiliser nitrogen including the effects of both nitrogen sources on feed quantity and quality, factors limiting nitrogen fixation and nitrogen fertiliser response, defoliation effects on white clover (Trifolium repens L.), animal health problems associated with clover and nitrogen fertiliser, and environmental effects. UDDER, a dairy farm simulation model, is used to predict the nitrogen fertiliser rate and white clover content in pasture necessary for optimum pasture production and feed quality. Maximum gross margins per ha and a high level of milksolids production per ha and per cow can be best achieved by combining nitrogen inputs from white clover and nitrogen fertiliser. The model predicts best results would be achieved with clover contents of 30-40% and nitrogen fertiliser rates of 100-200kgN/ha/yr. Keywords: dairying, feed quality, nitrogen fertiliser, nitrogen fixation, Trifolium repens
45
Ford, J. L., G. R. Cousins, Z. Jahufer, I. J. Baird, D. R. Woodfield e B. A. Barrett. "Grasslands Legacy - a new, large-leaved white clover cultivar with broad adaption". Journal of New Zealand Grasslands 77 (1 gennaio 2015): 211–18. http://dx.doi.org/10.33584/jnzg.2015.77.458.
Testo completoAbstract (sommario):
White clover (Trifolium repens L.) continues to play a pivotal role in the Australasian pastoral industry, despite increased use of nitrogen fertiliser on farms. Improved white clovers for dairy farming must be well adapted to the farm systems they are intended for, including increased rates of fertiliser nitrogen, higher stocking rates and access to irrigation. The breeding objective was to develop a white clover cultivar in evaluation systems that simulate modern farming practices, and test that cultivar in both New Zealand and Australia for adaptation and agronomic merit. This included breeding and early generation evaluation at research farms in the Manawatu and Waikato, with subsequent evaluations in these locations and farms in Southland and Victoria, Australia. This resulted in 'Grasslands Legacy', a new large leaved white clover cultivar bred for New Zealand and eastern temperate Australian pastures, which has shown significant (P
46
Kemp, D. R., D. L. Michalk e M. Goodacre. "Productivity of pasture legumes and chicory in central New South Wales". Australian Journal of Experimental Agriculture 42, n. 1 (2002): 15. http://dx.doi.org/10.1071/ea98171.
Testo completoAbstract (sommario):
Seven experiments were established across a range of environments (latitude 33°S) in central New South Wales to evaluate 52 legume cultivars and lines against currently recommended cultivars. Plots were grazed by either sheep or cattle after each harvest. Criteria for inclusion were that lines were either commercially available or in the process of being registered. Three experiments also included chicory. Sites had from 600 to 900 mm annual rainfall and were at altitudes of 440–1000 m. The 4-year program included the dry summer of 1990–91. White clover and subterranean clover were the most productive species over time. Among subterranean clovers, the subspecies subterraneum cultivars were more productive than the yanninicum or brachycalycinum subspecies. Other species such as balansa, Persian, strawberry, red and crimson clovers, lotus major and murex medic were more variable in production. These legumes often grew well in the establishment year, but failed to persist. Lucerne was in general, not as productive as white or subterranean clover. Caucasian clover and yellow serradella should be evaluated further as conclusive judgements could not be formed. Chicory was often the most productive species in the experiments, especially over the warmer 6 months of the year. It persisted under a 6-week harvest regime and during the drought year. The newer subterranean clover cultivars, Leura, Goulburn and Denmark all exceeded the production from the previously recommended cultivars, Woogenellup and Karridale, even though no major disease was evident in the later group. The lines 89820D and 89841E were sufficiently productive to warrant further evaluation and possible development as cultivars. In contrast, while Huia, Tahora, Bonadino and Tamar were often as productive as the recommended white clover cultivar Haifa, they were not consistently better. Where summer rainfall occurs and the annual rainfall exceeds 650 mm, the greater potential yield of white clover compared with subterranean clover justifies its use. However, no white clover cultivars survived the summer drought in 1990–91 as intact plants. Further work is needed to develop more drought-tolerant cultivars.
47
Scott, Alicia, D. R. Woodfield, Anne Allan, Dorothy Maher e D. W. R. White. "Inheritance and expression of transgenes in white clover". NZGA: Research and Practice Series 6 (1 gennaio 1996): 131–35. http://dx.doi.org/10.33584/rps.6.1995.3352.
Testo completoAbstract (sommario):
White clover plants from a range of cultivars can now be routinely transformed with cloned foreign genes. However, before transgenic white clover cultivars can be developed, these inserted genes must be stably inherited and expressed at appropriate levels in progeny. Primary transgenic white clover plants containing a uidA (GUS) reporter transgene were outcrossed and the inheritance and expression of the uidA gene was examined over two generations, in several different cultivar backgrounds. Both Mendelian inheritance and consistent expression in different genetic backgrounds were obtained from strongly expressing primary transgenic plants. However, primary transgenic plants with weak or variable expression gave non-Mendelian inheritance and inconsistent expression of the transgene in progeny plants. Transgenic BC1 plants were also intercrossed to produce a segregating F2 population containing individuals heterozygous or homozygous for the transgene. In these populations heterozygous and homozygous plants had similar levels of uidA gene expression. These results indicate that F2 plants, homozygous for a transgene, might be used to develop a transgenic cultivar. However, both selection of a primary transgenic plant with stable, high level expression of the introduced gene and progeny testing, to determine the influence of genetic background, are prerequisites to such a development. Keywords: gene expression, inheritance, transgene, uidA reporter, white clover
48
Febrer, Melanie, Foo Cheung, Christopher D. Town, Steven B. Cannon, Nevin D. Young, Michael T. Abberton, Glyn Jenkins e Dan Milbourne. "Construction, characterization, and preliminary BAC-end sequencing analysis of a bacterial artificial chromosome library of white clover (Trifolium repens L.)". Genome 50, n. 4 (aprile 2007): 412–21. http://dx.doi.org/10.1139/g07-013.
Testo completoAbstract (sommario):
White clover ( Trifolium repens L.) is a forage legume widely used in combination with grass in pastures because of its ability to fix nitrogen. We have constructed a bacterial artificial chromosome (BAC) library of an advanced breeding line of white clover. The library contains 37 248 clones with an average insert size of approximately 85 kb, representing an approximate 3-fold coverage of the white clover genome based on an estimated genome size of 960 Mb. The BAC library was pooled and screened by polymerase chain reaction (PCR) amplification using both white clover microsatellites and PCR-based markers derived from Medicago truncatula , resulting in an average of 6 hits per marker; this supports the estimated 3-fold genome coverage in this allotetraploid species. PCR-based screening of 766 clones with a multiplex set of chloroplast primers showed that only 0.5% of BAC clones contained chloroplast-derived inserts. The library was further evaluated by sequencing both ends of 724 of the clover BACs. These were analysed with respect to their sequence content and their homology to the contents of a range of plant gene, expressed sequence tag, and repeat element databases. Forty-three microsatellites were discovered in the BAC-end sequences (BESs) and investigated as potential genetic markers in white clover. The BESs were also compared with the partially sequenced genome of the model legume M. truncatula with the specific intention of identifying putative comparative-tile BACs, which represent potential regions of microsynteny between the 2 species; 14 such BACs were discovered. The results suggest that a large-scale BAC-end sequencing strategy has the potential to anchor a significant proportion of the genome of white clover onto the gene-space sequence of M. truncatula.
49
Gemell, L. G., E. J. Hartley e D. F. Herridge. "Point-of-sale evaluation of preinoculated and custom-inoculated pasture legume seed". Australian Journal of Experimental Agriculture 45, n. 3 (2005): 161. http://dx.doi.org/10.1071/ea03151.
Testo completoAbstract (sommario):
During 1999–2003, 293 samples of preinoculated and custom-inoculated lucerne, subterranean clover, white clover, red clover and miscellaneous species (mainly other clovers) were sourced from commercial outlets and assessed for numbers of rhizobia, seed pellet pH and toxicity, and nodulation in a ‘grow-out’ test. Average rhizobial counts were 8400/seed for preinoculated lucerne, 1380/seed for subterranean clover and <100/seed for white and red clovers and for the miscellaneous species. These counts compared poorly with the average counts of 35 100/seed, 13 800/seed and 10 000/seed for freshly-inoculated lucerne, subterranean clover and white clover, respectively. Thus, overall pass rates of the preinoculated seed were reasonable for lucerne (73%), marginal for subterranean clover (32%) and very low for white clover (3%), red clover (4%) and the miscellaneous species (0%). The ‘grow-out’ tests for nodulation were positively correlated with rhizobial numbers on seed, confirming the use of plate counting of rhizobia to assess quality of pre- and custom-inoculated seed. Many of the seed pellets were toxic to the 2 clover rhizobial strains tested, although the toxicity did not affect numbers of rhizobia on the seed. In light of these results and other data on rhizobial survival on seed, we suggest the current Australian standards for rhizobial numbers on pasture legume seed at the time of sale of 500/seed (very small-seeded legumes with seed numbers >750 000/kg) and 1000/seed (other larger-seeded species, seed numbers <750 000/kg) remain in place. We recommend shelf lives be restricted to 6 months for preinoculated lucerne and the annual medics, to 6 weeks for preinoculated subterranean clover, and to 2 weeks for white clover, red clover and other miscellaneous species. In the long-term, new products and procedures will hopefully enhance the numbers and survival of rhizobia on seed such that the needs of both manufacturers and customers are satisfied.
50
Jones, Chris, Warren Williams, Kerry Hancock, Nick Ellison, Alicia Scott, Vern Collette, Zulfi Jahufer et al. "Pastoral Genomics - a foray into the clover genome". NZGA: Research and Practice Series 12 (1 gennaio 2006): 21–23. http://dx.doi.org/10.33584/rps.12.2006.3035.
Testo completoAbstract (sommario):
Pastoral Genomics is engaged in applying molecular mapping and functional genomics to characterise and manipulate key phenotypic traits associated with improved productivity in the commercially important forage crop white clover (Trifolium repens L.). We report on the development of a framework linkage map for white clover and the application of this map to the identification of quantitative trait loci (QTL) associated with vegetative and seed yield traits. Homologues of genes responsible for the traits of interest have been identified and cloned in order to identify 'perfect markers' for marker assisted breeding and to develop a cisgenic® clover cultivar. We introduce western clover (T. occidentale), a diploid perennial clover species closely related to white clover, as a stoloniferous clover model to dissect low heritability traits initially intractable in white clover. We have identified extensive genetic variation in this species, which previously has been reported to be remarkably uniform. We have developed a framework map for T. occidentale and demonstrated conservation of marker order and spacing with white clover. An ethyl methane sulfonate (EMS) mutant population has been used to isolate three distinct groups of condensed tannin (CT) mutants. We have also investigated our model's transformation potential, achieving frequencies 2-3 fold higher than for white clover and suggest that this model is potentially useful for genomic analysis of white clover and other clonal species