Legumes have underpinned transformational change on New Zealand sheep and beef farms over the last 30 years. This was through an emphasis on ewe nutrition based on lucerne or red clover dominant pastures, and increased use of subterranean and white clovers on uncultivatable hill country. Pre- and post-weaning lamb growth rates have increased, and enabled earlier slaughter of heavier lambs. The farm systems results include greater numbers of hoggets mated, higher lambing percentages and greater ewe efficiency (kg lamb weaned/kg ewe mated). Extension packages to support legume use have compared growth rates of resident and legume-based pastures, economic analyses of successful farms and management packages for the most appropriate legume in different environments. Over the same period, the dairy industry rapidly expanded in cow numbers and area onto flat irrigated land on the Canterbury Plains. The nitrogen deficiency of perennial ryegrass was overcome by a linear increase in nitrogen fertiliser use. Environmental concerns from this intensification has led to a legislated nitrogen cap of 190 kg/ha.year. This, coupled with a recent trebling in urea price, has returned attention to increasing the white clover content of these pastures. Nitrogen applications can be minimised by using diverse pastures sown with a legume, herb and <8 kg/ha of perennial ryegrass. Work on other legumes, including annuals and those with condensed tannins, has to date failed to increase their use in most pastoral settings, with the exception of the perennial lupin which is adapted to high-aluminium soils in the South Island High Country.

In Australia, 71% of agricultural greenhouse gas (GHG) emissions are enteric methane (CH₄), mostly produced by grazing sheep and cattle. Temperate low CH₄ yielding legumes and herbs can mitigate enteric CH₄ production, but system-level GHG emissions need to be considered. The aims of the study were to: (1) devise a framework to assess GHG reductions when introducing low CH₄ yielding species; (2) assess mechanisms of CH₄ reduction in temperate legume and herb species for Australia; (3) use a case study to demonstrate expected changes to system-level GHG emissions with the introduction of low CH₄ yielding legumes; and (4) identify knowledge gaps and research priorities. Results demonstrate lowering emissions intensity (kg CO₂-equivalent/kg product) is crucial to mitigate GHG emissions, but livestock productivity is also important. Several pasture species have anti-methanogenic properties, but responses often vary considerably. Of the species investigated biserrula (Biserrula pelecinus) has great potential to reduce enteric CH₄ emissions, but in a case study its emission intensity was similar to subterranean clover (Trifolium subterraneum) but higher than lucerne (Medicago sativa). We conclude that there are temperate legumes and herbs with anti-methanogenic properties, and/or high productivity that could reduce total CH₄ emissions and emissions intensity of ruminant livestock production. There is also great diversity in some plant genotypes that can be exploited, and this will be aided by more detailed understanding of plant secondary compounds associated with CH₄ reduction. This review suggests an opportunity to formulate pasture species mixtures to achieve reduced CH₄ emissions with greater or equal livestock production.

Strawberry clover (Trifolium fragiferum L.) is periodically raised as an alternative perennial pasture legume for temperate regions of Australia. Its tolerance of waterlogging is widely known, yet its ability to persist through periods of soil moisture deficit is often understated. Other desirable characteristics include its stoloniferous growth habit and tolerance of mildly saline conditions. Only four strawberry clover cultivars have been registered in Australia, and the most popular, cv. Palestine, is a direct introduction, released in 1938 and first certified in 1951. Furthermore, strawberry clover’s distribution has largely been confined to niche environments, particularly waterlogged and saline areas. This paper reviews the taxonomy and breeding system, morphology, distribution and ecology, and subsequent transfer of strawberry clover to Australia. It reviews and maps the suitability of strawberry clover for perennial pasture systems in the medium–-high rainfall and irrigated temperate zones of Australia, with reference to future climates. The paper also highlights the breeding focus, commercialisation and marketing required to supersede cv. Palestine and lists the germplasm available in the Australian Pastures Genebank, with origins. We conclude that, although strawberry clover is unlikely to become a dominant perennial pasture legume species in Australia, it could be used in a wider range of environments than just those affected by salinity and/or waterlogging stress.

Context. There is interest in using serradella (Ornithopus spp.) in permanent pastures of the high rainfall zone of south-eastern Australia. However, there is little information concerning levels of hardseededness or patterns of seed softening in these environments.

Aim. This study quantified seed softening of serradella species in comparison with subterranean clover (Trifolium subterraneum L.) in the Southern Tablelands and Central Slopes districts of eastern Australia.

Methods. Mature seeds were placed in mesh pouches on the soil surface and were retrieved periodically to assess residual hard seed proportions throughout the growing season(s) in four experiments conducted over 2018 and 2019.

Key results. Patterns of seed softening among adapted cultivars of subterranean clover were consistent: initially high proportions of hard seed, followed by rapid softening from mid-summer to the end of autumn with the remnant portion of seeds remaining hard. In contrast, diverse patterns of seed softening were observed among serradella cultivars, ranging from highly soft-seeded through to high initial hard seed portions that either softened rapidly or softened over a lengthy period. Rates of seed softening were faster in the warmer/drier environment of Cowra compared to the wetter/cooler environment of Canberra.

Conclusions. The study revealed seed softening patterns among serradellas to be diverse and different to subterranean clover. This will affect management and suitability of serradella cultivars for permanent pastures.

Implications. In permanent pastures, serradellas that soften slowly over several years are likely to have limited regeneration in the year after pasture establishment with a high potential for weed invasion.

Context. Improving the stability of legumes in grasslands in the face of variable seasonal conditions is key to mitigating risks posed by drought.

Aims. We assessed the persistence of a range of legume species and cultivars in order to inform legume choice for pasture improvement and identify priority species for further development.

Methods. Twenty field experiments in four series were conducted at sites with contrasting seasonal and soil characteristics in the ‘high-rainfall’ (560–920 mm long-term average) Tablelands and Monaro regions of New South Wales, Australia. Legumes were grown as pure swards and assessed periodically for seedling density, plant frequency and dry matter for up to 5 years.

Key results. Legume dry matter production was positively correlated with plant frequency. However, most legumes persisted poorly at most sites, particularly on soils of lower fertility. Subterranean clover (Trifolium subterraneum) cv. Goulburn was the best performing cultivar of that species across sites on the Southern Tablelands and Monaro. Yellow serradella (Ornithopus compressus) cvv. Avila and Yellotas showed promising persistence, particularly under drought conditions. White clover (T. repens) was the most broadly adapted of the perennial legumes across a range of soils, but persistence was still inadequate at many sites. Lucerne (Medicago sativa) was approximately twice as productive as the next-most productive species when soil conditions suited its growth, but it failed to persist on acidic, low-fertility soils.

Conclusions. Serradella species (yellow and French, O. sativus) and white clover, in conjunction with subterranean clover, offer the best near-term prospects for diversifying legume productivity and resilience under variable seasonal conditions in tableland environments.

Implications. An increased focus on phenology and seed characteristics is suggested to improve the persistence of annual and facultative perennial legume species in grasslands. Serradella and white clover are identified as the highest priorities for cultivar development for tableland environments of south-eastern Australia.

Context. High-quality, summer-active pastures could improve meat production in south-eastern Australia by facilitating livestock finishing over summer, with legumes critical for enhancing the nutritive value of pasture mixes. Available legumes vary in their ability to withstand moisture stress and grazing.

Aims. We aimed to identify legumes suitable for a summer–autumn finishing system.

Methods. We tested pure swards of 12 cultivars across eight legume species in replicated small-plot experiments at Goulburn and Bombala, New South Wales, assessing productivity, persistence and warm-season nutritive characteristics over 2–3 years.

Key results. Lucerne (Medicago sativa) was clearly the most productive species during summer and outperformed the clovers (Trifolium spp.) in terms of persistence and productivity throughout most of the experimental period at both sites, except during autumn 2021 after high rainfall in March. Caucasian clover (T. ambiguum) was also highly persistent at both sites. Talish clover (T. tumens) and strawberry clover (T. fragiferum) were more persistent than white clover (T. repens) and red clover (T. pratense). White clover recovered strongly under high rainfall after drought, whereas red clover established rapidly but showed less capacity for post-drought recovery. Hybrid Caucasian × white clover was the least productive legume. Alternative clover species sometimes had slightly lower values of nutritive characteristics than white clover; red clover sometimes had distinctly lower values.

Conclusions. Lucerne performed best but several clovers were also productive, persistent and of high nutritive value over the summer–autumn period.

Implications. Talish, Caucasian and strawberry clovers warrant further investigation for inclusion in summer-active pastures in south-eastern Australia.

Context. Opportunity exists to expand serradella (Ornithopus spp.) use onto heavier, duplex soil types in permanent pasture environments of south-eastern Australia. This requires cultivars with appropriate flowering times and flowering-date stability (i.e. flowering at the same date in spring regardless of timing of the autumn break).

Aim. This work examined evidence of variation in flowering date and flowering-date stability in the NSW southern tablelands for a widely-used French serradella (O. sativus) cv. Margurita.

Methods. Seed (sourced from a commercial supplier) was sown 21 March 2019 (Canberra, ACT) and 231 individual plants were monitored for time to first flower. A subset of plants exhibiting ‘early’ or ‘late’ flowering were identified and their seeds collected. In 2020, seed from ~15 plants from each selection was sown in Canberra in late March and early May to represent an ‘early’ and a ‘later’ break of season (n = 3).

Key results. In the early-sown treatment, ‘early-flowering’ selections typically reached the median date of first flower (50%-flowering) from mid- to late August, while ‘late-flowering’ selections reached 50%-flowering early- to mid-September. When sown later, the ‘early-flowering’ selections began flowering from mid- to late September, while the ‘late-flowering’ selections flowered mid-September to early October. The ‘early’ selections exhibited greater flowering-date instability than ‘late’ selections and flowered particularly early when sown early. This indicated diversity within cv. Margurita for flowering-time control (e.g. vernalisation and/or photoperiod requirements).

Implications. Evaluating cultivars of serradellas for flowering date and flowering date stability in their target environment(s) is essential to ensure cultivars are suitably adapted to these environments.

Context. Serradellas (Ornithopus spp.) are promising alternative annual legumes to subterranean clover (Trifolium subterraneum L.), for permanent, temperate pastures. However, many cultivars exhibit unstable flowering dates across years. This is a risk for seed production and persistence.

Aim. This study assessed how vernalisation and photoperiod cues determine maturity type and flowering date stability among serradella cultivars.

Methods. First flower appearance was recorded for early and late maturing cultivars of yellow serradella (Ornithopus compressus L.), French serradella (Ornithopus sativus Brot.) and subterranean clover after exposure to six vernalisation treatments (0, 1, 3, 5, 7 or 9 weeks at 5°C) with subsequent growth under four photoperiods (8, 12, 16 or 20 h).

Key results. ‘Intrinsic earliness’ differed by only zero to three nodes for cultivars within species, indicating that maturity type was determined primarily by a cultivar’s responses to vernalisation and photoperiod. An interaction between these responses was observed, with a precipitous decline in the requirement for vernalisation when photoperiods exceeded 12 h. Many cultivars also displayed a persistent component to their vernalisation response, whereby long photoperiods (20 h) did not completely negate the response to vernalisation.

Conclusions. Later maturity was associated particularly with need for long exposure to the vernalisation treatment to minimise the duration from sowing to first flower appearance. Stable flowering is more likely when a cultivar has components of its vernalisation requirement that are not satisfied before autumn ends to prevent premature flowering, and a photoperiod response in spring that overrides any unmet vernalisation requirement.

Implications. Persistence by serradella cultivars requires selection for suitable responsiveness to vernalisation and photoperiod.

Context. The legume shrub/tree leucaena (Leucaena leucocephala (Lam.) de Wit.) is highly regarded as a cattle fodder, although it is considered an environmental weed in many parts of Australia.

Aims. We investigated the feasibility of developing a forage variety of triploid leucaena through interspecific hybridisation that is sterile (without seeds) as a strategy to mitigate its weed risk.

Methods. A conventional breeding strategy was used to create triploid hybrids from hand-crosses between tetraploid and diploid species of leucaena. Molecular markers were developed to confirm successful crosses and flow cytometry was used to confirm the ploidy level. The plants are being evaluated for flowering behaviour, seed and herbage production across two environmentally diverse sites at Carnarvon and Kununurra in northern Western Australia.

Key results. During 2018/19 and 2019/20, 2260 crosses between 45 different combinations of diploid females by tetraploid males and their reciprocals have created over 3000 putative triploid hybrid plants. This is the first time that triploids have successfully been created in Australia and 10 new parental combinations were created as a world-first.

Conclusions. A cohort of sterile triploid plants has been identified and selections will be made based on their edible biomass productivity, insect tolerance, capacity for regrowth after cutting, nutritive value and plant chemistry (including anti-methanogenic responses). A sterile leucaena variety will have application not only in Australian grazing systems but also in other tropical regions of the world.

Implications. A cost-effective technology for mass vegetative propagation of leucaena will be required for commercialisation of a sterile variety.

Context and aims. Freshly harvested seeds of temperate annual pasture legume species have physiological dormancy (PD), which delays the growth of the next generation and is thus an impediment to speed breeding. The aim of this study was to develop a method or methods of PD breaking that can achieve high germination (≥90%) within 5 days of picking freshly harvested seed.

Methods. In a series of experiments, PD breaking methods by themselves and in combination were tested on burr medic (Medicago polymorpha). The most promising methods were then tested on other annual medic species (Medicago spp.), subterranean clover (Trifolium subterraneum), and alternative species from six genera.

Key results. The successful PD breaking method involved drying pods overnight at 45°C, extracting and scarifying seed, placing seed on filter paper in a Petri dish along with non-dormant seed, imbibing seed with 4 μM benzylaminopurine, sealing the Petri dish, and incubating in the dark at 15°C. Highly dormant genotypes required the additional treatment of removing the testa.

Conclusions. We have developed an effective way of breaking seed PD in the 11 pasture legumes species from the seven genera tested. The rapid breaking of seed PD will assist speed breeding of annual pasture legumes, making it less laborious and time-bound than currently used methods.

Implications. The PD breaking methods are expected to assist basic science studies of annual pasture legume species and may be applicable to other species and genera.