The University of Queensland

Research Interests

• Yield gaps in mungbean crops across northern grains region, Australia
  GRDC funded project: Jan 2018 to Sep 2018 Mungbean crop yields in sub-tropical Australian farming systems are highly variable and risk of low yields lead to grower perception that they are a high risk crop. The factors causing the yield variability are poorly understood and a range of yield-reducing factors are likely to be important such as water availability limitations, nutrient availability, biotic factors and high or low temperature stresses. Without a very large amount of data and crop monitoring it is often difficult to attribute these diverse range of yield reducing-factors to understand which are most critical. In this study we used a paddock survey approach across three main mungbean growing areas in the northern region to assess paddock conditions and yields combined that with simulation modelling approach that captures the water supply and demand factors to determine the water-limited yield potential of mungbean crops across a diverse range of environments and growing conditions. Differences between observed or achieve crop yields and the simulated water-limited yield can be used to predict the yield gap. This can help quantify the potential to improve crop yields through improved management but also be used to identify factors other than water availability that may be reducing crop yields. In particular, the model can be used to infer the occurrence of stress events, such as temperature stresses (high or low) at critical periods and combinations of these with water stress may be associated with poor crop performance. Otherwise, other factors that the model does not capture, such as nutrient limitations or pathogen pressures may help to explain the yield gaps in a crop. It is intended that this analysis will help to identify the likely factors that may be related to poor mungbean crop performance.
• Mungbean physiology / agronomy
  GRDC funded project: Sep 2018 to Sep 2022 Mungbean [Vigna radiata (L.) Wilczek] are a pulse crop well suited to the climate of the northern grains region of Australia, historically facing challenges due to fluctuating production and therefore varied continuity of supply (Chauhan et al., 2010) resulting in grower perception of mungbeans as a low-yielding, unreliable crop. However, over the last ten years production levels have steadily increased as in response to improved varieties and high global prices for mungbean. Current production of mungbean in the northern grains region extends from southern NSW north to the Burdekin region in QLD in summer-dominant rainfall areas. Mungbeans are a valuable summer crop grown in rotation with winter and summer cereals and considered to be relatively heat and drought-tolerant, increasing its potential in areas where irrigation is limited. Growers can opportunistically double-crop mungbeans when the soil moisture profile is adequate following a cereal crop or sow onto fallow. These opportunity crops represent 40% of plantings, however yield in these crops tends to be close to the industry average (<0.9 t ha-1) and highly variable. The drivers of this variability and therefore grower risk are unclear (e.g. water, heat, nutrition, N-fixation) and remain a significant challenge to increasing yields for growers. Currently there are significant gaps in our understanding of mungbean yield including: factors driving yield components and photosynthesis across genotypes, physiological constraints of different varieties that limit yield performance, yield potential and susceptibility of phenological stages to abiotic stress including heat, water deficits and the interaction between heat x water limitations. This limits yield optimisation as we don’t understand the key factors drive yield and crop productivity, and particularly why different genotypes have higher yields than others and dynamics of harvest index in mungbean. Controlled environment glasshouses will be initially utilised to determine the relationship between leaf development and yield, flower number and conversion to seed. Experiments will explore the genotypic variability in mungbeans in both vegetative and reproductive phases to determine the factors driving yield determination under optimal / sub-optimal conditions. Findings will then be field validated. Relationships between timing / type of stress and how they can be managed by agronomic practices will be investigated using both controlled environment and field trials. Glasshouse trials will initially characterise the impact of stress (water/heat) on vegetative and reproductive growth in mungbean genotypes. Genotypes will be assessed for tolerance / sensitivity to high temperatures, drought and interactions that are likely under future climate predictions. Findings will then be field validated using lysimeters and rain-out shelters. A trial program, targeted at assessing mungbean genotype and phenotype response to time of sowing (TOS, spring to summer) and seasonal variability, will be delivered over three years in one location. Trials will also use heat chambers to apply heat stress to well-watered and rainfed plants at two key windows at flowering and podding over three seasons. Detailed physiology measurements will occur at the Gatton site. Findings from Output 1-2 to be used to calibrate the APSIM mungbean model in future projects. In-house statistical analysis capacity will be utilised within UQ with biometricians experienced in agricultural research.