Can the development of drought tolerant ideotype sustain Australian chickpea yield?

Terminal drought is a major problem in many areas where chickpea is grown on stored soil moisture. This is exacerbated by the lack of a targeted breeding approach focusing on key traits contributing to yield formation under water-limited conditions. There is no study to develop a chickpea ideotype and test it against commercial varieties under various management systems across the Australian grain belt. This study proposed a chickpea ideotype that can be grown in water deficit areas and compared its performance with commercial chickpea genotypes across the Australian grain belt. Important traits for ideotype construction and breeding were identified and tested against selected commercial varieties in silico in the Australian grain belt using the APSIM crop model. The key phenological, morphological and physiological traits were determined in the field at the University of Sydney's IA Watson Grains Research Centre near Narrabri for ideotype targeting. Five commercial chickpea genotypes (Sonali, PBA Hattrick, Kyabra, Tyson and Amethyst) were selected for evaluation against the chickpea ideotype. The constructed chickpea ideotype showed 76% resemblance to Sonali which performed well under water limited conditions. Simulated yield ranged from 760 to 3902 kg/ha across the Australian grain belt, with consistently higher yield in the ideotype compared with the commercial cultivars. The growing environments were grouped into three major clusters using the soil water deficit method with varying water stress levels. It is evident that grain filling is the most critical stage where soil moisture deficit caused chickpea yield losses up to 16.5% in the present study. By incorporating key target traits and targeting the right environment, chickpea yields can be sustained in the Australian grain belt or in an area having similar agro-ecological characteristics.