Twenty-one hybrids developed from crossing seven lines and three testers were assessed for the extent of combining ability effects, heterosis and genetic parameters for yield and related contributing traits. The analysis of variance uncovered that there were highly significant differences for all the studied traits except panicle weight among parents and parents vs. crosses. The two promising lines GZ 9461-4-2-3-1 and GZ 1368-S-5-4 were seen as a good general combiner among lines for most of the traits, while among the testers, the parental variety Sakha S 300 was superior. Two crosses out of hybrids, GZ 9461-4-2-3-1 / Milyang 349 and GZ 1368-S-5-4 / IR14K642 exhibited positive and highly significant SCA effects for grain yield plant^-1, respectively. The maximum positive and highly significant mid-parent heterosis and heterobeltiosis for grain yield plant^-1 were observed. The five crosses GZ 1368-S-5-4 / Sakha S 300, GZ 1368-S-5-4 / IR14K642, GZ 9461-4-2-3-1 / Milyang 349, GZ 9461-4-2-3-1 / Sakha S 300 and GZ 9461-4-2-3-1 / IR14K642 recorded the highest values and maybe extensively used in rice programs by adopting a heterosis breeding strategy. The additive gene action was noticed for days to 50% flowering, plant height, flag leaf area, number of panicles plant^-1, panicle length, panicle weight, panicle density index, spikelets fertility, 1000-grain weight, and grain yield plant^-1. Grain yield plant^-1 was highly significantly and positively correlated with plant height, flag leaf area, number of panicles plant^-1, panicle weight and panicle density index indicating the significance of these traits as determination criteria in yield enhancement.