Understanding the number of genes governing fertility restoration and isolation of potential restorers on maldandi source of male sterility in rabi sorghum [Sorghum bicolor (L.) Moench]

Abstract

DSMR-4 and DSMR-8, two promising restores, were crossed with M 31-2A maldandi cytoplasm. The obtained hybrids were assessed in three sets of tests, F2: BC1F1, F2: F3, and F4 kharif: F4 rabi generation, in order to determine the number of genes driving the segregating pattern. Three genes are involved in the initial set of segregation patterns for both crosses: in the F2 generation, there were 54 fertile: 10 sterile and in the BC1F1 generation, there was 1 fertile: 1 sterile. Two of these genes are required for the restoration and function in a duplicate complimentary manner. Further, both the crosses were grown in F3 generation to confirm the stability of restorers. They were segregated in the ratio of 10 true-breeding families and 44 segregating families, which confirmed F2 ratio. Further, only true breeding 49 to 54 families of both the crosses were forwarded to F4 generation and evaluated in both kharif and rabi seasons. In both seasons, they segregated in the ratio of 4 true-breeding families and 6 segregating families. The current study revealed the reliability of gene action for fertility restoration increased from F2 to F4 because of the fixation of alleles.