Fine mapping of Rf2, a major locus controlling pollen fertility restoration in sorghum A1 cytoplasm, encodes a PPR gene and its validation through expression analysis

Abstract Sorghum is one of the pioneering cereal crops where cytoplasmic male sterility ( CMS ) was successfully exploited for mass production of F 1 hybrid seed. Mapping genes for fertility restoration ( Rf ) is an important aspect of understanding the molecular basis of fertility restoration in crop plants. In this study, we fine‐mapped a fertility restoration locus, Rf2 of sorghum reported earlier (Jordan, Mace, Henzell, Klein, & Klein, ), involving two F 2 populations (296A × RS 29 and 296A × DSV 1) and newly developed SSR markers delimited Rf2 locus to 10.32‐kb region on chromosome 2. The Rf2 locus was tightly linked with two new SSR s, MS ‐ SB 02‐3460 (0.14 cM ) and MS ‐ SB 02‐3466 (0.75 cM ) on both sides, and hosted only one gene ( Sobic.002G057050 ) of PPR gene family. Another new SSR marker developed in the study, MS ‐ SB 02‐37912, forms the part of PPR gene and could act as a perfect marker in marker‐assisted breeding for fertility restoration involving Rf2 in sorghum breeding. The strong involvement of Sobic.002G057050 gene in fertility restoration was supported through RNA expression analysis.