Inheritance of fertility restoration in pigeonpea

Fertility restoration system in five CMS-based pigeonpea [(Cajanus cajan (L.) Millspaugh] hybrids was studied during kharif 2010 at International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Patancheru, Andhra Pradesh. Two hybrids ‘ICPH 2671’ and ‘ICPH 2740’ which had the same male parent but different females segregated in F₂ in the ratio of 12 fertile (F): 3 partial fertile (PF):1 sterile (S), and in BC₁F₁ generation as 2 fertile: 1 partial fertile: 1 sterile, suggesting that fertility restoration in these hybrids was controlled by digenic dominant epistatic interaction. The progenies derived from hybrid ‘ICPH 3359’ fitted well to an F₂ ratio of 9 F: 6 PF: 1 S, and 1 F: 2 PF: 1 S in BC₁F₁ generation, indicating the involvement of two major genes with incomplete dominant epistasis. Progenies of the other two hybrids ‘ICPH 4012’ and ‘ICPH 4344’ segregated in F₂ in the ratio of 9 F: 3 PF: 4 S, and 1 F: 1 PF: 2 S in BC₁F₁ generations, suggesting that pollen fertility was controlled by digenic recessive epistatic gene action. Results of the present investigation revealed that fertility restoration of A₄ CMS system in pigeonpea was governed by two major genes but with different types of epistatic interactions in different crosses.