Tagging of four Rf genes with selective genotyping analysis in rice (Oryza sativa L.)

Abstract

Wild abortive type of cytoplasmic male sterility (WA-CMS) is commercially used for hybrid rice seed production. The linked markers can be used for selection of plants with desirable traits. Tagging of Rf genes was carried out using recessive and dominant class analysis in a large F2 population from the cross IR58025A×IR42686R. Pollen fertility and seed setting were evaluated at the flowering and maturity stages, respectively. Forty-seven highly sterile and 23 fertile homozygous plants were selected from F2 population for molecular marker assay. Four Rf genes identified in a good restorer line with high-quality derived from a random mating composite population at the International Rice Research Institute (IRRI). The genetic distance from Rf3 locus with flanking markers RM443 and RM315 on chromosome 1 was 3.7 and 21.2 cM, respectively. RM258, RM591, RM271 and RM6737 on the long arm of chromosome 10 were linked with the Rf6 gene with distance of 7.4, 22.6, 6 and 2.9 cM, respectively. Rf6 was flanked by RM6737 and RM591. The Rf4 gene located on chromosome 7 was linked with RM6344 at a genetic distance of 10.6 cM. RM519 and RM7003 were linked with other Rf gene on chromosome 12 at a genetic distance of 8.5 and 20.8 cM, respectively. Closely linked markers identified in this study could be used for marker assisted selection in a hybrid rice breeding program. A new Rf locus on chromosome 12 that designated Rf7 was linked with RM7003 and RM519.