Heterosis and Combining Ability Studies in Rice (Oryza sativa L.)

The investigation was carried out with three male sterile lines and 10 restorers and their 30 hybrids along with the hybrid check, HRI-174. Maximum panicle exertion per cent was recorded for AMPS 18A (80.27%) and highest duration of floret opening was noticed for APMS 17A (153 min). APMS 15A was noticed to be a good combiner with high mean performance for un-filled grains per panicle, spikelet fertility per cent and 1000-grain weight, while, APMS 17A was to be a good combiner with high mean for grain density. In contrast, APMS 18A was noticed to be a good combiner with high mean performance for ear bearing tillers per plant. The results also revealed RTCNP 2 and RTCNP 38 to be good combiners for grain yield per plant, filled grains per panicle, spikelet fertility per cent and 1000-grain weight. A perusal of the results on mean performance, heterosis and specific combining ability revealed the superiority of APMS 15A x RTCNP 2, APMS 15A x RTCNP 150, APMS 17A x RTCNP 2 and APMS 17A x RTCNP 38 hybrids. These hybrids had recorded more than 30 per cent higher grain yield, compared to the check and were identified as promising rice hybrids in the study.