Genetic diversity reveals synergistic interaction between yield components could improve the sink size and yield in rice

Intensive breeding programs have increased rice yields, strongly contributing to increasing global food security during the post-green revolution period. However, rice productivity has reached a yield barrier where further yield improvement is restricted by inadequate information on the association of yield components, and morphological and physiological traits with yield. We conducted a field experiment to evaluate (i) the contribution of morphological and physiological traits to yield and (ii) quantify the trade-off effect between the yield components in rice, using a mini-core collection of 362 rice genotypes comprising geographically distinct landraces and breeding lines. Our data point towards multiscale coordination of physiological and morphological traits associated with yield and biomass. Considerable trait variations across the genotypes in yield ranging from 0.5 to 78.5 g hill(-1) and harvest index ranging from 0.7% to 60.7% highlight enormous diversity in rice across the globe. The natural elimination of trade-off between yield components revealed the possibility to enhance rice yield in modern cultivars. Furthermore, our study demonstrated that genotypes with larger sink sizes could fix more carbon to achieve a higher yield. We propose that the knowledge thus generated in this study can be helpful for (a) trait-based modeling and pyramiding alleles in rice-breeding programs and (b) assisting breeders and physiologists in their efforts to improve crop productivity under a changing climate, thus harnessing the potential for sustainable productivity gains.