Inheritance of fertility restoration of A₄ cytoplasm in pearl millet [Pennisetum glaucum (L.) R. Br.]

Present investigation was carried out to study the mode of inheritance of fertility restoration for A₄ cytoplasm using pollen fertility and seed set per cent as criterion in determining the fertile and sterile plants. Two CMS lines of A4 cytoplasm were crossed with two fertility restorers generating four F₁ crosses, namely, ICMA 99111 x PPMI 1003, ICMA 99111 x PPMI 1087, ICMA 03999 x PPMI 1003 and ICMA 03999 x PPMI 1087, their F₂s and backcross generations. All the F₁s were completely fertile indicating complete fertility restoration. F₂s and backcross generations were evaluated at IARI, New Delhi and IARI Regional Centre, Dharwad during summer 2017 and X² test was applied to test the significance. At both the locations, all the F₂ segregating populations fit well into a Mendelian ratio of 15:1 indicating digenic duplicate dominance of fertility restoring genes with X² value of 0.82, 2.90, 0.04, 3.97, 4.86, 4.98, 0.02, 1.26, 3.15, 4.98, 3.15 and 0.02. The F₂ hypothesis was verified with the observed frequency of segregating plants fitting well into 3:1 ration with X² value of 5.45, 1.93, 4.93, 0.60, 2.83, 0.44, 4.94, 2.77, 3.33, 0.13, 4.08 and 1.51. It is further confirmation of the findings that fertility restoration is indeed governed by two duplicate genes. Association between pollen fertility and seed set per cent was significant and positive.