Genetic analysis and gene mapping of a rice recessive male sterile mutant

With 3 figures and 2 tables Male sterility of rice is one of the major genetic tools used for hybrid rice production. In this study, a spontaneous male sterile mutant, SC-ms-2, was obtained from the F₄ progeny of the cross D 297B x Changfeng B. Microscopic observation revealed that the microspores were developed abnormally and the tapetum cells were incrassated during microsporogenesis. Genetic analysis indicated that male sterility of SC-ms-2 was controlled by a single recessive gene. By using bulked segregant analysis on two F₂ populations developed from crossing SC-ms-2 with Hua B and 'Nipponbare', this gene was finely mapped between two simple sequence repeat (SSR) markers on chromosome 9, RM24451 and RM7048, with genetic distance of 0.3 cM and 0.6 cM respectively, and the approximate physical distance was 172 kb. Our results showed that this gene was distinguished from all the other male sterility genes in rice reported and it was designated ms92(t), temporally. Moreover, candidate genes in the region of 172kb, including the rice homologue to the Arabidopsis MALE STERILITY1 (MS1) gene, were surveyed and discussed.