Identification and Genetic Characterization of a New d10 Mutated Indica Rice Germplasm

Plant architecture is a determining factor for yield of cereal crop rice. Multi-tiller and dwarf mutants are useful germplasms for the study of rice plant architecture. In this research, we investigated a new multi-tiller and dwarf mutant, Jiahecong’ai (JHCA), and compared its genetic characteristics with 6 other rice varieties or lines. Two F 2 populations were developed by crossing JHCA with Gaoliangdao 1 (GLD1) and Guangchang 13 (GC13), which were used for further studies. Our results showed that the extreme dwarf and multitiller phenotype of JHCA was controlled by a recessive locus named xmd(t) . The xmd(t) locus was fine mapped to an interval between XMd-SSR4 and XMd-SSR25 marker on chromosome 2, which spans 190 kb in length including 28 annotated genes. Allelic sequence analysis revealed that the xmd(t) of JHCA has a 40-bp deletion in D10 gene, which encodes a carotenoid cleavage dioxygenase 8 (OsCCD8) involved in strigolactone (SL) biosynthesis pathway. Further genetic analysis suggested that JHCA should be a good rice germplasm for studying plant architecture in rice as well as metabolism interactions between gibberellin and strigolactone based on the reinforcement of dwarfing effect by d10 and sd1 .