Heterosis for yield and associated traits in rice (Oryza sativa L.) using CMS lines under saline-alkali soil

F-1 heterosis over better parent, standard variety (Narendra Usar 2) and standard hybrid (NUSD 3) was studied in 40 crosses of rice for yield and five other attributing traits under saline-alkali soil. Highly significant and positive heterosis for grain yield plant(-1) was expressed over better parent, standard variety and standard hybrid in nine crosses viz., IR 58025 A x IR 72048-B-R-2-2-2-1-B, IR 58025 A x NDR9830119, NMS 4A x NDRK 5094, NMS 4A x CSR(S) 14-1-4-0, IR58025 A x Narendra Usar 3, IR 58025 A x IR 71829-3R-73-1-2-B, IR58025 A x 21-2-5-B-1-1, IR 58025 A x NDRK 5086 and NMS x IR 64. However, the cross combination IR 58025 A x IR 71829-3R-73-1-2-B exhibited heterosis in positive direction for almost all the studied yield attributes along with grain yield plant(-1). Highly significant hybrid vigour for grain yield plant(-1) indicating the additive heterotic effect of such component traits. Morever, IR 58025 A x IR71829-3R-73-1-2-B exhibited only better parent heterosis (64.45%) for spikelet fertility per cent. Indicating spikelet fertility percent is greatly affected by the saline-alkali soil because the numerical production of pollen grain is reduced significantly in the flowers of salinized plants.