A network of 21 experiments was established across nine countries on four continents and spanning both hemispheres, to evaluate the relative performance of early generation perennial cereal material derived from wheat, rye, and barley and to inform future breeding strategies. The experimental lines were grown in replicated single rows, and first year production and phenology characteristics as well as yield and persistence for up to three years were monitored. The study showed that the existing experimental material is all relatively short-lived (≤3 years), with environments that are milder in summer and winter generally conferring greater longevity. No pedigree was superior across this diverse network of sites although better performing lines at the higher latitude sites were generally derived from Thinopyrum intermedium. By contrast, at lower latitudes the superior lines were generally derived from Th. ponticum and Th. elongatum parentage. The study observed a poor relationship between year 1 performance and productivity in later years, highlighting the need for perennial cereal material with greater longevity to underpin future experimental evaluation, and the importance for breeding programs to emphasize post-year 1 performance in their selections. Hybrid lines derived from the tetraploid durum wheat generally showed greater longevity than derivatives of hexaploid wheat, highlighting potential for greater use of Triticum turgidum in perennial wheat breeding. We advocate a model in future breeding initiatives that develops perennial cereal genotypes for specific target environments rather than a generic product for one global market. These products may include a diversity of cultivars derived from locally adapted annual and perennial parents. In this scenario the breeding program may have access to only a limited range of adapted perennial grass parents. In other situations, such as at very high latitude environments, perennial crops derived from barley or rye may have a better chance of success than those derived from wheat. In either case, development and selection of the perennial parent for adaptation to local environments would seem fundamental to success.

Perennial grains have potential to contribute to ecological intensification of food production by enabling the direct harvest of human-edible crops without requiring annual cycles of disturbance and replanting. Studies of prototype perennial grains and other herbaceous perennials point to the ability of agroecosystems including these crops to protect water quality, enhance wildlife habitat, build soil quality, and sequester soil carbon. However, genetic improvement of perennial grain candidates has been hindered by limited investment due to uncertainty about whether the approach is viable. As efforts to develop perennial grain crops have expanded in past decades, critiques of the approach have arisen. With a recent report of perennial rice producing yields equivalent to those of annual rice over eight consecutive harvests, many theoretical concerns have been alleviated. Some valid questions remain over the timeline for new crop development, but we argue these may be mitigated by implementation of recent technological advances in crop breeding and genetics such as low-cost genotyping, genomic selection, and genome editing. With aggressive research investment in the development of new perennial grain crops, they can be developed and deployed to provide atmospheric greenhouse gas reductions.

Perennial cereals may offer a novel forage source in mixed farming enterprises while improving the sustainability of grain farming. There has been limited analysis of the quality of this forage type and its likely value to mixed grazing/cropping farming systems. This study evaluated the biomass and grain production of four wheat × wheatgrass hybrid experimental lines under four simulated grazing regimes; nil defoliation (grain only; D0), defoliate once (D1), defoliate twice (D2) and defoliate twice followed by a simulated hay cut (D3), and compared performance to a winter wheat, Wedgetail, and the perennial grass Thinopyrum intermedium. Early biomass production of the perennial entries was significantly less than Wedgetail (P = 0.01). Grain yield from Wedgetail was generally higher (P < 0.001) than all other lines. As defoliation frequency increased, the comparative difference in grain yield between Wedgetail and the hybrid entries decreased, with lines OK7211542 and 11955 exceeding the grain yield of Wedgetail in the D3 treatment. Cumulative annual biomass production of the hybrid lines exceeded that of Wedgetail, though the seasonal production differed markedly. Generally there was limited decline in perennial plant population between April and December in both years of the experiment. Defoliation had little impact on perennial plant survival; however, none of the hybrids could sustain a significant plant population beyond the second summer of the experiment. Yield declines of the hybrid entries was due to increasing plant mortality, rather than a predisposed yield limitation of the germplasm, as all hybrid entries either maintained or increased their grain yield on a per plant basis. In contrast, the perennial grass maintained a constant population for the duration of the experiment. Dry matter digestibility and energy content of all forages tested were high, averaging 80.2% and 13.3 MJ ME/kg DM, respectively. Crude protein was higher (P < 0.001) in Th. intermedium and the hybrid entries with 62% and 25% more crude protein than Wedgetail, respectively. All cereals had very high potassium : sodium and low calcium : phosphorus ratios, which indicated the need to provide mineral supplements to grazing animals to maintain growth rates and manage animal health disorders, similar to conventional grazing cereals. This paper discusses the role perennial cereals could play in a sustainable expansion of the cropping zone in south-eastern Australia.

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.