Heterotic expression of two line hybrids in rice (Oryza sativa L.)

Heterosis explored in four Thermo-sensitive Genic Male Sterile (TGMS) lines and 22 non-TGMS testers by making 88 crosses.The magnitude of relative heterosis, heterobeltiosis and standard heterosis with checks (CORH 2 and ADTRH 1) wereestimated.Thehybrids,GD98029xIR61608-213,GD9804xIR61608-213and GD 98014 x RR 166-645 could be exploited for earliness as they exhibited negative and significant standard heterosis for days to 50 per cent flowering over the checks. Top yielding hybrids viz., GD 98049 x IR 63875-196-2-2-1-3, GD 98014 x TKM11, GD 98049 x TKM 11, GD 99017 x TKM 12 exhibited significant standard heterosis over CORH 2 and ADTRH 1. Most of the high yielding hybrids manifested significant positive heterosis for yield contributing characters viz., more number of productive tillers per plant, long panicles, more number of filled grains per panicle, spikelet fertility and 1000 grain weight. Hence, these hybrids may be used for commercial cultivation in two line hybrid rice.