Genetics Analysis Of Small Grain And Dwarfing Rice Mutant Xiaoxiang'ai

The success of rice breeding is largely depends on the discovery and exploit of varieties with good agronomic traits, especially the use of the dwarfing varieties to develop new highly productive cultivars, nowadays one of the most important work on breeding is to build gene bank with abundant dwarf genes for future cross breeding, therefore we can develop new varieties which grow in different environments. Research on dwarf mutant molecular mechanism could be very facilitated to understand the growth and of rice in different stages, and provide methods for theoretical direction of rice breeding job. The plant paterial was found in the process of hybridation among three different parents, named as Xiaoxiang'ai (xxa), which is characteristic dwarfing, small grain, dark green leaves. We use the Nipponbare and xxa as two parents to build fine mapping population F2, the dwarf and the semi dwarf is segragated by ratio1:3, which show the phenotype is controlled by signal recessive gene. Reports showed F2population of high cultivar and xxa is segragated by ratio9:6:1, which shows another gene involved in regulation of the dwarf phenotype. xxa is sensitive to GA3through GA3and BL sensitivity analysis, which proves that this variety has sd-1(codes GA20ase). So we named this unknown gene as xxa. And xxa was preliminary mapped on5chromosome between two SSR marks RM18408and RM18457, about2.5cM, expansed the mapping population and mapped xxa between two indel marks F81and F85, about70kb, then we predicted the mutant and confirmed the mutant site of this gene through gene sequencing and analysised the expressing of XXA in NIL through real time quantitative PCR.