Modern rice varieties adapted to aerobic (dryland) conditions have expanded to new rice growing systems thanks to their plasticity in adapting to rainfed and irrigated conditions. This is important because, as water becomes scarce in paddy rice regions (as it is already in Australia), there will be a move towards tropical to subtropical dryland rainfed rice with attendant problems of drought and low temperature. To assess rice adaptability in the wet season of the semi-arid subtropical conditions of coastal central Queensland, field experiments were established for a late season (in January) planting in 2014 and early season planting in November 2015 with 13 varieties developed by Australian Agriculture Technologies (AAT) Ltd were seeded in a vertisol soil. This was to assess their adaptation to rainfed conditions and their response to strategic irrigation. Water scarcity and low temperature prior to and at flowering were important factors constraining yield. Early flowering varieties in the late season planting escaped the otherwise cold and drought stress during the reproductive stage and had higher yields. In the second year, earlier planting made possible with strategic irrigation avoided the low temperature constraint on yield, but without follow-up strategic irrigation, yields were still low. The average yield of varieties increased from 1.5 times (AAT 4) to 16.3 times (AAT 15) with strategic irrigation compared with rainfed yields averaged across years. The increase in yield with strategic irrigation was associated with a greater leaf area index, spikelet fertility, and instantaneous water use efficiency during flowering. Strategic irrigation concentrated roots in the top 15 cm, but differences in yield between varieties under rainfed conditions were not related to root properties. It is important to consider variations in flowering time, yield potential, and drought patterns when developing rice varieties for rainfed semi-arid tropical conditions, as well as when quantifying the benefits of strategic irrigation.

Mungbean is grown as a summer crop in subtropical climates globally. The global demand for mungbean is increasing, and opportunities exist to expand production regions to more marginal environments, such as southern Australia, as an opportunistic summer crop to help meet the growing global demand. Mungbean has the potential to be an opportunistic summer crop when an appropriate sowing window coincides with sufficient soil water. This expansion from subtropical to temperate climates will pose challenges, including low temperatures, a longer day length and a low and variable water supply. To assess mungbean suitability to temperate, southern Australian summer rainfall patterns and soil water availability, we conducted field experiments applying a range of water treatments across four locations with contrasting rainfall patterns within the state of Victoria (in southern Australia) in 2020–2021 and 2021–2022. The water treatments were applied prior to sowing (60 mm), the vegetative stage (40 mm) and the reproductive stage (40 mm) in a factorial combination at each location. Two commercial cultivars, Celera II-AU and Jade-AU, were used. Water scarcity during flowering and the pod-filling stages were important factors constraining yield. Analysis of yield components showed that increasing water availability at critical growth stages, viz. the vegetative and reproductive stages, of mungbean was associated with increases in total biomass, HI and grain number in addition to increased water use and water use efficiency (WUE). Average WUEs ranged from 1.3 to 7.6 kg·ha⁻¹·mm⁻¹. The maximum potential WUE values were 6.4 and 5.1 kg·ha⁻¹·mm⁻¹ for Celera II-AU and Jade-AU across the sites, with the estimated soil evaporation values (x-intercept) of 83 and 74 mm, respectively. Nitrogen fixation was variable, with %Ndfa values ranging from 9.6 to 76.8%, and was significantly affected by soil water availability. This study emphasises the importance of water availability during the reproductive phase for mungbean yield. The high rainfall zones within Victoria have the potential to grow mungbean as an opportunistic summer crop.

Mungbean is predominantly cultivated within a subtropical climate, and its potential for cultivation in temperate regions as a summer crop has not been comprehensively assessed. This research investigates the influence of temperature and seasonal variation with sowing time on mungbean phenology, growth and yield at five locations within the temperate environment of southeastern Australia (Victoria). Five mungbean varieties (Jade‐AU, Celera II‐AU, Golden Dragon, Putland and Crystal) were evaluated across two times of sowing (TOS) (spring and early summer) over 2 years (2020–2021 and 2021–2022 summers) at sites in southwestern (Hamilton and Horsham), northeastern (Rutherglen) and northwestern (Ouyen and Woomelang) Victoria. These locations are characterised by winter‐dominant rainfall patterns with sporadic summer rainfall events, which can be significant. Annual rainfall varied across sites: low rainfall (< 350 mm, Ouyen and Woomelang), medium rainfall (350–450 mm, Horsham) and high rainfall (> 350 mm, Hamilton and Rutherglen). Early sowing coincided with lower soil temperatures, leading to delayed emergence and reduced establishment. However, TOS did not significantly influence grain yield, except at Rutherglen (TOS 1, 715 kg/ha; TOS 2, 1576 kg/ha). Grain yield was correlated with grain number and biomass, significantly contributing to variations in yield. The variety Jade‐AU exhibited superior performance in low and medium rainfall regions in Victoria, whereas Putland and Crystal varieties demonstrated optimal performance in high rainfall zones. Under dryland cropping conditions, northeastern Victoria (e.g., Rutherglen) may represent the most promising opportunity for mungbean cultivation. Nevertheless, when selecting varieties for summer mungbean cultivation in southern Australia, it is imperative to consider differences in days to first flowering, yield potential, heat stress tolerance and rainfall patterns.