Abstract:Panicle apical abortion is often observed in rice production, which impairs the number of grains per panicle, the seed setting rate and the yield of single plant, and should be avoided in breeding practice. The dense and erect panicle is a plant type adaptable to dense planting. It is of importance to isolate the genes related to these two traits in molecular design breeding. Here, we present the research result of a rice panicle mutant zhao1, which displays the dense panicle and panicle apical abortion. Either dense panicle or panicle apical abortion was segregated independently in the F2 population derived from zhao1 crossed with IRAT129. Genetic analysis showed that the dense and erect panicle trait is controlled by a single dominant gene, while the panicle apical abortion trait may involve no more than two pairs of genes. Based on the linkage analysis and map-based cloning at both traits respectively, the gene DEP1 was found to be the candidate for the dense panicle trait in zhao1 which carries the identity mutation as the dep1. The linkage mapping and map-based cloning to the trait of panicle apical abortion finally delimited the candidate gene to the physical interval of 6.85-6.93 Mb on chromosome 3, where 8 putative genes are annotated. The gene LOC_Os03g12790 was observed with the most significant decrease on transcriptional profile, and served as the best candidate for the panicle apical abortion phenotype. Collectively, our results laid the foundation for the future cloning of the functional gene in rice.