Combining ability and heterosis were determined in a population obtained from crosses between four indigenous testers and 10 exotic lines and grown under irrigated condition during 2014–15. Analysis of variance (ANOVA) revealed the presence of significant variance due to general combining ability (gca) as well as for specific combining ability (sca) among the parents for all the traits. Among the parents, Marriya, Moroc 9–75, V Morles and BH 902 were good general combiners for grain yield and its component traits. On the basis of sca effects, Yardu x Lakhan showed significant sca effect for grain yield under both the irrigated and rainfed conditions. Pristage x BH 902, Himani x RD 2508 and Atahualpa x Lakhan were recorded as desirable for number of grains per spike, whereas Marriya x K 603 for chlorophyll content. For grain yield, the maximum per cent heterosis over standard check (K 603) was observed in Moroc 9–75 x BH 902, Atahualpa x RD 2508, Marriya x Lakhan and Moroc 9–75 x K 603. Moroc 9–75 x RD 2508, Marriya x Lakhan and Rihane x BH 902 under rainfed conditions, while Atahualpa x BH 902, Yardu x Lakhan and V-Morles x RD 2508 exhibited heterobeltiosis under irrigated condition (2014–15).