Grasslands Tribute: a multi-purpose white clover for Australasia

Pastoral-based animal production systems are under increasing pressure to provide the high quantity and quality of feed needed for optimal ruminant performance. The capacity of farmers to increase forage yield further, solely by increasing fertilizer inputs or through improved pasture management, is limited. Emerging requirements to balance industry production targets against the need to reduce greenhouse gas emissions and N losses pose further challenges. Plant breeding is being asked to deliver results more urgently than at any time previously, and this review attempts to highlight issues that might limit the prospects for future progress by seeking lessons from four past examples: (i) white clover breeding gains and the need to consider the complexity of the grazed grass-clover mixed sward, with its tendency for cycling in plant species composition; (ii) a systems field trial of new and old grass ⁄ clover cultivars, and how the complexity of growth of perennial forage crops, and the dynamic optimality required for sustainable harvesting might limit our ability to breed for 'yield' per se; (iii) the manipulation of a physiological trait (low 'maintenance' respiration) and the implications of such changes for plant fitness and G · E interactions; and (iv) an hypothesis-driven development of a trait (high-sugar grasses) and the value of 'proof of concept' studies, the requirement of scientific understanding of the mechanisms of trait expression, and how one might in future go about assessing breeding achievements. We discuss the general ecological considerations around shifts in the frequency distribution of traits in new populations, whether altered conventionally or by genetic modification, and how selection for a particular trait might inadvertently reduce both fitness and persistence. A major priority for breeding, we propose, might be to revisit previously abandoned traits that affected the physiological performance of forage species, armed now with a capacity to monitor gene expression at the molecular level, and so unravel ⁄ control the G · E interactions that limited their benefits. We also discuss how a 'loss of yield advantage' of new cultivars, seen when tested several years after sowing, requires urgent investigation and propose this might be associated with fitness costs of perenniality. Finally, we argue for a careful reconsideration of what are realistic expectations for systems field trials and that focus on forage breeding might be shifted more to 'proof of concept' studies, critical experimental design, comparing 'traits' rather than 'cultivars', and the wider ecological assessment of fitness and function of traits in the plant, community and ecosystem.

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“…Data (a) and (b) from Woodfield, 1999; (c) and (d), Woodfield et al. , 2001; (e) and (f), Woodfield et al. (2003).…”

Section: Examples Revisited: Seeking New Insightsmentioning

confidence: 99%

Past lessons and future prospects: plant breeding for yield and persistence in cool‐temperate pastures

Parsons

Edwards

Newton

et al. 2011

Grass and Forage Science

138

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“…These half-sib families were further screened and elite plants from 11 half-sib families originating from Sustain, Crau, Southern Europe II and Syrian were recombined to produce Grasslands Tribute, a medium-to large-leafed white clover. Grasslands Tribute exhibited consistent performance and persistence under dryland grazing in a series of seven New Zealand experiments (Woodfield et al 2003). It was the best medium-to large-leafed cultivar under both sheep and dairy grazing, with only the large-leafed cultivar Kopu II performing better under dairying.…”

Section: Grasslands Tributementioning

confidence: 91%

“…Grasslands Tribute was released in 2003 from a collaborative 55 program started in 1991 to select white clover with tolerance to drought stress (Woodfield et al 2003). The cultivar was originally developed from a collection of 20 white clover lines that included several Australian ecotypes, a range of New Zealand cultivars and breeding lines, and three ecotypes collected from southern Europe and Syria.…”

Section: Grasslands Tributementioning

confidence: 99%

“…The cultivar was originally developed from a collection of 20 white clover lines that included several Australian ecotypes, a range of New Zealand cultivars and breeding lines, and three ecotypes collected from southern Europe and Syria. The selected lines exhibited drought tolerance, rust resistance and high dry matter (DM) yield (Caradus et al 1991;Barker et al 1993;Woodfield et al 2003). From this material, 45 genotypes that exhibited high persistence and herbage yield were selected from four lines: Sustain, Crau, Southern Europe II and Syrian.…”

Section: Grasslands Tributementioning

confidence: 99%

“…It was the best medium-to large-leafed cultivar under both sheep and dairy grazing, with only the large-leafed cultivar Kopu II performing better under dairying. Grasslands Tribute showed strong growth in all seasons, but had very good cool season growth and good drought tolerance (Woodfield et al 2003). Grasslands Tribute is still available commercially in Australia.…”

Section: Grasslands Tributementioning

confidence: 99%

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Prospects for improving perennial legume persistence in mixed grazed pastures of south-eastern Australia, with particular reference to white clover

Hayes¹,

Ara

Badgery

et al. 2019

Crop Pasture Sci.

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This review examines the prospect of improving perennial legume adaptation to grazed mixed pasture swards across the higher-altitude regions of south-eastern Australia through improved management, particularly as it relates to soil fertility. The range of adapted perennial species available to farmers often remains limited to only one perennial forage legume species, white clover (Trifolium repens L.). Despite recent advances in cultivars for increased persistence in dryland environments, white clover remains sensitive to drought with its inherently shallow root system and limited capacity to restrict water loss from herbage. With few alternative species likely to become widely available in the foreseeable future, prospects for extending the boundaries of perennial legume adaptation likely rely on a dual approach of improving soil fertility and further genetic improvement in white clover. Improved soil fertility would focus on overcoming soil acidity and addressing nutrient deficiencies, particularly of phosphorus, potassium, boron and molybdenum, which tend to be more widespread in the target region. Addressing these soil constraints would alleviate periodic moisture stress by: (1) increased water availability through improved infiltration and soil hydraulic properties; (2) increased root growth to maximise exploration of the soil volume; and (3) better maintenance of plant cell structures to foster improved osmotic regulation. However, the extent to which white clover adaption may be extended remains an issue of further research. This review highlights an opportunity for further genetic improvement of white clover by focusing on improving the capacity to recover from periodic droughts through seedling regeneration. Further breeding efforts in white clover should examine the feasibility of selecting for hard seed characteristics more similar to the best-adapted subterranean clover (Trifolium subterraneum L.) cultivars across this region to promote ongoing seedling regeneration.

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Relative performance of white clover (

Jahufer

Ford

Cousins

et al. 2021

Crop & Pasture Science

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Assessment of the relative performance of white clover (Trifolium repens L.) cultivars, using multi-year and multi-location seasonal growth trials, is key to identification of material with specific and broad adaptation. This paper is based on a multi-year and multi-location study of 56 white clover entries comprising 14 commercial cultivars and 42 experimental synthetic lines evaluated for seasonal growth under rotational grazing across four locations in New Zealand over 4years. The four locations (and animals grazing) were: Kerikeri (beef cattle), Aorangi (beef cattle), Ruakura (dairy cattle), Lincoln (sheep). Significant (P<0.05) genotypic variation among the 56 entries, and genotype × year, genotype× location and genotype× season interactions, were estimated. We were able to identify cultivars and experimental synthetics with specific and broad adaptation to the three grazing management types. Cvv. AberDance, Apex, Demand, Prestige, Quartz and Riesling, with leaf size ranging from small to medium–large, showed highly above-average performance under sheep grazing. Synthetic lines 15 and 45 also had highly above-average performance under sheep grazing. Cvv. Legacy and Kopu II showed above-average performance under cattle and dairy grazing. Synthetics 15, 48, 49, 44, 22 and 18 and cv. Quartz had above-average performance under all three grazing managements. Synthetics 27, 33 and 38 had highly above-average performance across all three grazing managements and were superior to all 14 cultivars evaluated. Several of these superior synthetics are being tested across multiple grazing environments. Among the 14 cultivars evaluated, Legacy and Quartz showed superior seasonal growth performance across the three grazing managements. Quartz is being evaluated in several on-farm trials across temperate regions of the world.

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Grasslands Tribute: a multi-purpose white clover for Australasia

Cited by 16 publications

References 11 publications

Past lessons and future prospects: plant breeding for yield and persistence in cool‐temperate pastures

Past lessons and future prospects: plant breeding for yield and persistence in cool‐temperate pastures

Prospects for improving perennial legume persistence in mixed grazed pastures of south-eastern Australia, with particular reference to white clover

Relative performance of white clover (

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