Inheritance of fertility restoration in A4 cytoplasm of Pigeonpea (Cajanus cajanifolius L.)

A set of three medium-duration CMS lines ICPA 2043, ICPA 2047, and ICPA 2048 were used in study to investigate fertility restoration by making twenty-eight test crosses at the Department of Pulses, TNAU, Coimbatore. ICPA 2047 exhibited fertility restoration ranging from 0-40 % with negligible pod setting except for the cross ICPA 2047×ICP 3181. In contrast, sixteen F1s derived from ICPA 2048 showed pollen fertility ranging from 10-48 % except for the cross ICPA 2048 × ICP 9224. Similarly, sixteen F1s derived from ICPA 2043 demonstrated 15-38 % pollen fertility, with ICPA 2043 × LRG 41 showing 98 % fertility and good pod setting. Among the hybrids, ICPA 2043 × LRG 41 exhibited high fertility, ranging from 95.58 % to 98.67 % over two years. This suggests that dominant fertility-restoring genes from the restorer parent were incorporated into the hybrid, which showed consistent fertility restoration across different years. In the current investigation, the restorer line ICP 3181 demonstrated monogenic inheritance of fertility restoration in crosses with ICPA 2047 and ICPA 2048, following 3:1 ratio. Conversely, the cross ICPA 2043 × LRG 41 exhibited a digenic duplicate dominance inheritance pattern. These results suggest that the fertility restoration in pigeonpea can be inherited monogenically or di-genically, depending on the hybrid. The identified hybrids, particularly ICPA 2043 × LRG 41 demonstrate significant potential for improving fertility restoration and enhancing productivity in pigeonpea breeding programs.