Vol. 7, Issue 9, Part F (2025)

A study was conducted to evaluate fertility restoration and sterility maintenance in 32 inbred lines crossed with three CMS lines (CMS-47A, CMS-38A, and CMS-103A), producing 96 F₁ hybrids. These hybrids were classified as restorers, maintainers, or partial restorers based on the proportion of fertile and sterile plants. Among the evaluated crosses, 36 (37.50%) were completely fertile, 29 (30.21%) were sterile, and 31 (32.29%) exhibited partial fertility. Out of the 32 inbred lines, eight (USDA-46, USDA-64, NDI-18, NDI-21, NDI-33, RSLP-34, RSLP-36, and PB-892) consistently restored fertility across all CMS lines, confirming the presence of dominant restorer gene (Rf1). Six inbreds (USDA-109, USDA-122, USDA-160, USDA-173, USDA-192, and USDA-224) acted as maintainers, while six others (USDA-145, NDI-23, GMU-520, GMU-713, EC-198072, and Phule Bhaskar) showed partial fertility restoration. Differential restoration was observed across CMS lines, with several inbreds such as USDA-46, USDA-64, NDI-18, NDI-21, NDI-33, RSLP-34, and PB-892 performing as restorers in multiple CMS backgrounds. The variation in fertility expression suggests the influence of modifying genes, nuclear background of the female parent, and complex interactions between cytoplasmic and nuclear factors. Overall, the study identified promising restorer and maintainer lines essential for new restorer and CMS lines in maintenance breeding and hybrid development programme.