Tagging of fertility-restoring genes in Iranian restorer rice promising line DN-33-18

Cytoplasmic-genetic male sterility system can be used to exploit heterosis in grain crops only when the effective restorer lines are available. Crosses between CMS line Neda A with three promising lines DN-32-6، DN-33-1 and DN-33-18 were made. Studies on pollen and grain fertility of these crosses showed that the cross of Neda-A/DN-33-18 had more than 80% pollen and grain fertility in the F1 generation. The inheritance of fertility restoration genes in F2 population of this cross was evaluated at flowering and grain filling stages. Pollen staining test showed segregation of 312 fertile: 16 sterile plants that in accordance with Mendelian 15:1 ratio، representing existence of two genes in the genome of DN-33-18. 12 SSR markers were used for molecular tagging of these fertility-restoring genes showing that 4 markers including RM258، RM171، RM591 and RM3148 produced polymorphic bands between parents. Linkage analysis showed that marker RM3148 located on chromosome 1 linked with Rf3 gene at a genetic distance of 19. 7 cM and markers RM258 and RM171 located on chromosome 10 flanked to Rf4 gene at the genetic distances of 3. 1 and 6. 3 cM، respectively. These markers are useful in MAS (marker-assisted selection) for transferring and pyramiding of fertility restoring genes in hybrid rice breeding programs.