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Red clover (Trifolium pratense L.) is a perennial forage crop grown in mixture with grasses or as a pure stand. It is valued for its nitrogen fixation capacity, benefits in organic farming, high quality forage, and beneficial effects on the soil structure. However, the lack of persistence is a major problem in red clover and the lack of winter hard...
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This paper summarizes published literature concerning different factors that could affect the content and composition of isoflavones in red clover (Trifolium pratense L., Fabaceae). Influence of genotype, plant part, geographic origin, ontogeny and storage conditions of raw material are discussed. Statistical analysis of available data on the profi...
Lolium arundinaceum [(Darbyshire) tall fescue] toxicosis is responsible for substantial beef production losses in the United States, due to its negative effects on reproduction, growth and feed efficiency. These effects are consequences of toxic alkaloids within tall fescue. Interseeding legumes, such as Trifolium pratense (red clover), into pastur...
Red clover is one of the most utilized forage in agriculture and contains many of the isoflavones known for their human health benefits. The objectives of this study were: i) to quantify, using HPLC analysis, isoflavones in 77 accessions from the USDA core collection and a Brazilian line; ii) to verify possible relationships depending on their orig...
Citations
... There is, however, strong genotype x environment interactions on red clover winter survival, and in some locations and years freezing tolerance plays a role [19]. Genetic variation in winter survival, freezing tolerance and clover rot resistance has been described [20][21][22][23][24]. Red clover has been shown to be more resistant to clover rot after a period of cold acclimation than before, both when incubated under humid conditions in a greenhouse [22,25] or under an artificial snow cover in darkness at a low positive temperature [17]. ...
... There is, however, strong genotype x environment interactions on red clover winter survival, and in some locations and years freezing tolerance plays a role [19]. Genetic variation in winter survival, freezing tolerance and clover rot resistance has been described [20][21][22][23][24]. Red clover has been shown to be more resistant to clover rot after a period of cold acclimation than before, both when incubated under humid conditions in a greenhouse [22,25] or under an artificial snow cover in darkness at a low positive temperature [17]. To our knowledge the effect of the length of the cold acclimation period on resistance to clover rot has so far not been investigated. ...
... Our results indicate that cold acclimation before infection increases resistance to clover rot during prolonged incubation with the fungus (Fig. 1), as previously observed [17,22,25]. The results also show that the higher resistance in cold acclimated plants is not simply due to avoidance of a "cold shock" upon incubation at low temperature, since the effect of cold acclimation was very clear under incubation at 16 °C. ...
Background
There is a lack of knowledge on the combined effects of different stresses on plants, in particular different stresses that occur during winter in temperate climates. Perennial herbaceous plants in temperate regions are exposed to many different stresses during winter, but except for the fact that cold temperatures induce resistance to a number of them, very little is known about their interaction effects. Knowledge about stress interactions is needed in order to predict effects of climate change on both agricultural production and natural ecosystems, and to develop adaptation strategies, e.g., through plant breeding. Here, we conducted a series of experiments under controlled conditions to study the interactions between cold (low positive temperature), clover rot infection (caused by Sclerotinia trifoliorum) and freezing, in red clover (Trifolium pratense) accessions. We also compared our results with winter survival in field experiments and studied associations between stress and shoot growth.
Results
Exposure to low positive temperatures (cold acclimation) induced resistance to clover rot. There was a clear negative interaction effect between freezing stress and clover rot infection, resulting in up to 37% lower survival rate compared to what would have been expected from the additive effect of freezing and infection alone. Freezing tolerance could continue to improve during incubation under artificial snow cover at 3 °C in spite of darkness, and we observed compensatory shoot growth following freezing after prolonged incubation. At the accession level, resistance to clover rot was negatively correlated with growth in the field during the previous year at a Norwegian location. It was also negatively correlated with the shoot regrowth of control plants after incubation. Clover rot resistance tests under controlled conditions showed limited correlation with clover rot resistance observed in the field, suggesting that they may reveal variation in more specific resistance mechanisms.
Conclusions
We here demonstrate, for the first time, a strong negative interaction between freezing and infection with a winter pathogen. We also characterize the effects of cold acclimation and incubation in darkness at different temperatures on winter stress tolerance, and present data that support the notion that annual cycles of growth and stress resistance are associated at the genetic level.
... Worldwide, red clover occupies ?4 million ha (Riday, 2010) and is an important component of pastures that sustain productivity and income for subsistence farming communities, such as the Aymara in the Andean plateau (López et al., 1998). Red clover is a key component in forage systems for its N fixation ability (Vleugels, 2013). Carlsson and Huss-Danell (2003) reported that the extent of N fixation by red clover can be up to 373 kg N ha −1 . ...
Pedigree maps are useful for germplasm exploration and identification of genetic bottlenecks. The primary objective of this study was to construct pedigree maps for red clover (Trifolium pratense L.) accessions held in the Margot Forde Germplasm Centre (MFGC) in Palmerston North, New Zealand. Pedigree data from accessions introduced into the MFGC between 1934 and 2016 were used. Data were filtered for accessions with breeding activity. A total of 30 founding accessions was identified, of which 25 were categorized as “New Zealand Broad,” two as “English Broad,” another two as “English Giant Hybrid,” and one as “Cotswold Broad.” The first synthetic form was identified from parents derived from English Broad and English Giant Hybrid. Influencing founder accessions were also identified. A relationship between introductions, relatedness, and geographic origin was found. The inbreeding and kinship coefficients were estimated across the population. The largest number of traced generations was eight. A total of 1742 accessions was used in the estimation of relatedness coefficients, with mean relatedness of 0.005. Overall mean inbreeding was 0.56%. Among the accessions with nonzero inbreeding coefficients, inbreeding was 10.68%. A sharp increase in inbreeding was found in the 1990s. Although inbreeding remained stable in the last three decades, a relationship between inbreeding and new introductions into the collection was found (r = 0.62). We conclude red clover diversity has been successfully maintained at MFGC during the past 80 yr. However, risk in loss of diversity is present unless germplasm exploration techniques, such as pedigree analysis, and novel breeding patterns are undertaken.
... Chromosome doubling in RC may improve agronomic performance, as polyploidy is associated with hardiness (Thompson and Lumaret 1992) and increased pest resistance (Nuismer and Thompson 2001). Increased disease resistance, particularly in clover rot (Sclerotinia sp.) is also reported for tetraploid RC by some authors (Vaverka et al. 2003;Vleugels 2013). Tetraploidy may also increase yields of DM and N (Frame 1976) due to the larger cells required by additional chromosomes (Anderson 1971). ...
... DM yields are important for livestock farmers and N yields are often used as a proxy to estimate nitrogen (Carlsson and Huss-Danell 2003). Tetraploid RC is cited as yielding more DM and N in the aboveground biomass than diploid (Frame 1976;Vleugels 2013;Amdahl et al. 2016). The tetraploid varieties trialled here (Amos and Maro) yielded higher DM and N than the diploids at the first cut in both years of cultivation, although the primary cause of this was more likely the later flowering date than ploidy, as later flowering varieties are expected to yield the bulk of their yield at the first cut. ...
... Some studies predict higher clover rot resistance in tetraploid RC (Vaverka et al. 2003;Vleugels 2013). Here the diploid varieties Astred and Ruby were more resistant than the tetraploids in 2015, but no significant varietal effects were observed in 2016. ...
Nitrogen (N) is the most limiting nutrient in crop production. Legumes such as red clover can provide N through biofixation, but securing nitrogen in soil for subsequent crop production must also be considered. Variety selection and management in red clover cropping can influence soil mineral nitrogen (SMN) availability. A field trial to investigate this was conducted with six varieties, under one and two cut management, over 2 years. Dry matter (DM) and N yield, Sclerotinia resistance and SMN availability were assessed. Low DM and N yields (1.6–2.4 t DM ha⁻¹ and 54–83 kg N ha⁻¹) in the first year of cultivation allowed ~ 40 kg N ha⁻¹ to become available, but high DM and N yields (10.2–14.6 t DM ha⁻¹ and 405–544 kg N ha⁻¹) allowed ~ 20 kg N ha⁻¹ to become available. Wetter weather in 2015 caused significantly more SMN losses than 2016 (20 kg N ha⁻¹ in 2015 and 5 kg N ha⁻¹ in 2016). The varieties Amos, Maro and Milvus lost significantly more SMN in the winter period, which may have been caused by more severe infection of Sclerotinia (these varieties were 50–80% more severely infected other varieties). Varietal effect was non-significant for winter losses in 2016, where no significant varietal differences in Sclerotinia infection were observed. 1 cut made ~ 41 kg N ha⁻¹ available in the growing season of 2015, whilst 2 cut made significantly less (37 kg N ha⁻¹). Cutting was non-significant in 2016 but 1 cut was less susceptible to losses in the winter period. Cutting in 2015 did not significantly affect herbage DM and N yields in the first or second cut of 2016.
... This can occur through increased allelic diversity, as higher diversity in immunity genes can boost recognition of pathogens (Spurgin & Richardson, 2010), or through the supplementary expression of genes related to immunity through multiple genomes (King, Seppälä, & Neiman, 2012). Vleugels (2013) proposed that polyploidy may contribute to resistance through a broader range of resistance occurrence. RC, as an obligate out-crosser, has mostly heterozygous genotypes. ...
The rapidly growing population will soon require a near doubling of food production. This increase must be achieved in a manner that maintains environmental integrity, preserves public health and resolves food access and distribution equalities. The use of forage legumes in arable rotations can make significant and multidimensional contributions to this sustainable intensification and this paper reviews the potential contribution of red clover (Trifolium pratense L.), with particular reference to sustainable cereal production in conservation agriculture systems. The use of red clover as a tool in soil fertility-building and the multiple benefits to the cropping system in which it is used is described. The benefits discussed include atmospheric nitrogen fixation, soil conservation, structural soil improvements and a suite of agroecosystem services including increased soil microbial activity, the phytoremediation of polluted soils and the provision of food for pollinators. Reported allelopathic weed suppression by red clover cover crops and the role of modern plant breeding in creating new varieties that further enhance system sustainability is also discussed. Finally, as economic considerations will always impact on adoption rates, the profitability of red clover rotations in terms of silage value and yield benefits is taken into account.
... Late varieties give most of their annual yield at the first cut and will regrow with less vigour than early varieties. Some authors cite late varieties as storing more reserves in the root system (Vleugels, 2013), which may also be of agronomic significance. Classification is more spectrum than dichotomy and some varieties could be described as 'intermediate', i.e. falling somewhere between early and late classification. ...
... The response of prostrate varieties to cutting as opposed to grazing also remains unknown. Vleugels (2013) investigated whether a prostrate growth habit caused resistance to clover rot (Sclerotinia sp) using the prostrate varieties Astred, Crossway and Broadway, but found no correlation between growth habit and disease resistance. ...
