Microsatellites based Parental Polymorphism Survey in Elite Restorer Lines of Rice for Stacking Wide-compatibility Trait

Astudy was undertaken during kharif (June, 2021-November, 2021) at ICAR-Central Rice Research Institute (CRRI), Cuttack, Odisha, India to identify polymorphic simple sequence repeat (SSR) markers between the parental lines of two rice crosses: Cross-I (CR 22–153-1×Lemont) and Cross-II (CR 22–153-1×CR 22–1-5-1). The primary goal was to screen for parental polymorphisms that could facilitate marker-assisted background selection (MABS) to expedite the recovery of the recurrent parent genome (CR 22–153-1) in a marker-assisted backcross breeding (MABB) program aimed at introgressing the wide compatibility gene ‘S5n’ into the elite restorer line CR 22–153-1. A total of 320 hypervariable SSR markers, uniformly distributed across all 12 rice chromosomes, were employed for the polymorphism survey. Among these, 96 markers (30%) were polymorphic between CR 22–153-1 and Lemont, while 89 markers (27.81%) showed polymorphism between CR 22–153-1 and CR 22–1-5-1. The extent of polymorphism observed between CR 22–153-1 and Lemont ranged from 20.7% to 48.2% across the twelve chromosomes, while that between CR 22–153-1 and CR 22–1-5-1 ranged from 20.7% to 41.4%. These identified polymorphic SSR markers provided a valuable resource for precise background selection in backcross and near-isogenic line (NIL) populat ions in both the crosses. Their use enabled the effective introgression of the ‘S5n’ gene while minimizing linkage drag, thereby facilitating the development of wide-compatible, high-yielding restorer lines.