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]

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.