Insights into the genetic basis of yield and its components in rice (Oryza sativa L.) through generation mean analysis

Generation mean analysis conducted was to recognize the inheritance patterns of yield-related traits in rice populations developed from crosses between salinity-tolerant (Saltol 1 QTL) and phosphorus (P) starvation-tolerant (Pup1 QTL) backcross inbred lines. The study involved four crosses: BIL33 × C16-1-2-8, BIL752 × D5-1-3-2-1, BIL1094 × C16-1-2-8 and BIL1102 × D5-1-3-2-1, aimed at developing multiple stress-tolerant versions of CR 1009 Sub1 and ADT 37 varieties. Six generations - Pt1, Pt2, F1, F2, BC1 F and BC2F were evaluated for thirteen quantitative traits during Kharif 2023-2024 at Agricultural College and Research Institute, TNAU, Madurai. Scaling tests revealed significant epistatic interactions for most traits across crosses. Grain yield showed complementary epistasis with significant interaction effects in all crosses, while traits like plant height and flag leaf characteristics displayed varying patterns of gene action. The existence of both additive and non-additive gene effects raises the possibility that selection may be postponed to future generations. The study advises maintaining larger populations during the initial generations and applying pedigree selection from the F4 generation onward to achieve effective trait enhancement. These findings provide valuable insights for developing breeding strategies to pyramid salinity and phosphorus starvation tolerance in rice varieties.