Context Pearl millet (Pennisetum glaucum L.) is a key dryland staple crop suffering significant yield losses under heat and drought stress. Both marginal and productive ecologies of pearl millet cultivation require distinct ideotypes for breeding, whereas strong genotype × environment interactions and multiple correlated traits complicate simultaneous selection. Aims This study aimed to identify high-performing and stable pearl millet genotypes for marginal (A1) and favorable (AB) environments by using integrated multi-trait and stability-based selection indices. Methods A global diversity panel of 242 pearl millet inbred lines (PMiGAP) was evaluated over three kharif seasons (2022–2024) at ICAR-IARI, New Delhi. Nine agronomic traits were recorded and analyzed using mixed models. Genotypes were assessed using MGIDI, WAASB and WAASBY indices. Environment-specific ideotypes were defined and predicted genetic gains were estimated at 15% selection intensity. Key results Significant genotype, environment and genotype × environment effects were observed for all traits. Moderate to high heritability was recorded for flowering time and panicle length whereas yield traits showed low to moderate heritability. MGIDI identified 37 superior genotypes per environment. Predicted gains included −4.60% for days to flowering and +13.7% for panicles per plant for A1 and +13.4% for grain yield per panicle in AB environment. WAASB and WAASBY identified IP 12020, IP 8949, IP 18293-P152, PT-732B-P2, and IP 5207 as high-performing and stable. Conclusions The integrated MGIDI–WAASB–WAASBY framework enabled objective selection of superior genotypes combining multi-trait performance and stability across multi-environment. Implications The identified genotypes provide valuable material for breeding programs targeting both drought-prone and favorable environments and can accelerate genetic gain and yield stability in pearl millet.
This article belongs to the collection: Australian Grasslands Symposium 2025 “Seeds of Change”.
Context Climate change is increasing temperatures, affecting the water cycle and other climate variables. In south-eastern Australia, winter rainfall has declined, whereas summer rainfall has remained stable or increased slightly. Future projections indicate that these trends will continue, and the summer–early autumn feed gap in grazing systems dominated by temperate pasture species is predicted to increase. Tropical perennial species are responsive to summer rainfall and may be a suitable addition to grazing systems, although their potential distribution is not known. Aim Our aim was to model and compare the potential distribution of six tropical pasture species under a historic baseline climate (1981–2010) and 2050 (2035–2065) future climate scenarios (by using two contrasting global climate models; MIROC-H, CSIRO-Mk 3.0) for Australia, with a focus on south-eastern Australia. Methods Species distribution based on climatic suitability of Cenchrus clandestinus, Chloris gayana, Digitaria eriantha, Megathyrsus maximus, Panicum coloratum var. makarikariense and Desmanthus virgatus was modelled using CLIMEX. Outputs were restricted by soil pH and land-use suitability to form a combined model of species distribution. Key results On the basis of where these species are currently sown, they occupy only a proportion of their potential. The 2050 climate scenarios suggest that the potential distribution of these species will decrease in northern Australia. In south-eastern Australia, suitability will increase if temperatures rise with minimal change to rainfall (MIROC-H A2), but decrease if rainfall decreases significantly (CSIRO-Mk 3.0 A2). Conclusions Our study indicated that these species may be suitable in new areas, including south-eastern Australia under both current and future climate scenarios. Further field testing is required to confirm their persistence, productivity, interaction with soils, and position in the landscape. Suitability of these grasses could provide an additional feedbase strategy for adapting to a changing climate. Modelling is subject to limitations, owing to parameter assumptions, exclusion of some soil and management factors, and uncertainties inherent in climate projections; these can be addressed through integration of finer-scale environmental data and targeted field validation.
Context Canola (Brassica napus L.) is an important oil crop that requires high nitrogen rates, but is sensitive to ammonium (NH4+-N) toxicity. Aims To determine whether genotypes exhibit variation in NH4+-N toxicity, and whether NH4+-N toxicity may be ameliorated by mixing nitrate (NO3−-N) and NH4+-N in various ratios, or by providing NH4+-N and NO3−-N in various sequences. Methods Using glasshouse experiments, we tested the growth of two NH4+-N toxicity-sensitive genotypes [SC03-1 (codenamed G30) and Zhongshuang4B (G3)] and two NH4+-N toxicity-resistant genotypes [Tarcoola-22 (G26) and ZY001 (G16)] under five NH4+:NO3− ratios at the 1.5 vegetative stage and three NH4+:NO3− ratios at seed maturity. We then selected the most NH4+-N-resistant (ZY001) and -sensitive (SC03-1) genotypes to grow at alternating nitrogen form supplies until the 1.5 vegetative stage. Key results In general, ZY001 had the highest growth and yield, especially at 50:50 and 25:75 NH4+:NO3− ratios. NH4+-N toxicity was mitigated when NH4+-N supply was combined with relatively high concentrations of NO3−-N. When alternating NH4+-N and NO3−-N supply, canola genotypes consistently performed poorly with NH4+-N supply and improved with NO3−-N. Conclusions Higher concentrations of nitrate relative to NH4+-N, and the use of nitrate alone (either before or after NH4+-N fertilisation), were associated with improved canola growth and physiological parameters under glasshouse conditions. The genotype ZY001 exhibited superior performance among the four genotypes studied. Implications Using nitrate instead of NH4+-N as a nitrogen source may improve canola growth under glasshouse conditions. The ZY001 genotype showed tolerance to NH4+-N toxicity and may be useful for future studies under field conditions.
Enteric methane (CH4) emissions from ruminant livestock are a major source of greenhouse gases in northern Australian grazing systems, where the extensive, low-input nature of production limits the applicability of alternative mitigation strategies such as feed additives. Tropical forage legumes therefore represent one of the few practical abatement options available, offering mitigation through both direct suppression of rumen methanogenesis and indirect improvements in animal productivity. This review synthesises evidence from in vitro, in vivo and farm-scale studies and integrates these findings with production-system modelling and agronomic assessments to evaluate CH4 abatement potential under extensive grazing conditions. In vitro studies demonstrated an average 12.1% reduction in CH4 yield across tropical legume species, while in vivo studies reported a comparable mean reduction of 13.8%. Legume inclusion rate (% of dietary dry matter) emerged as the primary predictor of CH4 response. Production-system modelling across low-, medium- and high-productivity grazing systems showed that legume incorporation reduced emissions intensity by an average of 28%, with approximately 82% of the reduction attributable to productivity gains and 18% to direct suppression of enteric CH4. A multi-criteria prioritisation framework combining CH4 abatement potential with agronomic suitability identified a small number of high-potential species. Leucaena leucocephala consistently produced the greatest direct CH4 suppression, whereas Desmanthus and Stylosanthes spp. offered broader environmental adaptation and greater scalability despite more modest direct abatement. These findings suggest that effective CH4 mitigation in northern Australian grazing systems will require a portfolio of legumes tailored to regional conditions. Tropical legumes are an immediately deployable mitigation strategy, although their full potential will depend on overcoming constraints to establishment, persistence and adoption in commercial grazing systems.
