Simultaneous improvement of lodging resistance and grain yield by stacking dep1 with elite genes in rice

Lodging-tolerance is one of the most important goals in rice breeding. Due to its semi-dwarfism phenotype, dep1 can potentially improve lodging-tolerance. In this study, dep1 together with other three alleles, gs3, gn1a and ipa1, were integrated into high yield breeding strategy by conventional crossing and four combinations including dep1-gn1a, dep1-gs3, dep1-ipa1, and dep1-gs3-ipa1 were obtained. Though all the combinations showed plant phenotype similar to dep1, such as semi-dwarfism, short dense panicle, and short and erect flag leaf, their 1000-grain weight were observed to increase. Both dep1-ipa1 and dep1-gs3-ipa1 were characterized with improved lodging resistance and high yielding potential, while grain yield in both dep1-gn1a and dep1-gs3 dramatically decreased due to their low seed setting rate. Furthermore, specifically altered expression pattern of auxin and cytokinin related genes and abnormal stigma structure were found in two double mutant lines. Overall, current study demonstrated the potential of pyramiding dep1 conferring lodging-resistant trait with other high-yield related genes in cultivating elite rice varieties and additionally, providing a series of novel core germplasm for new insights into the interplay of dep1, gn1a, gs3, and ipa1 in regulating rice morphogenesis.