Heterosis for yield and its components in rice (Oryza sativa) under temperate conditions

Eight rice (Oryza sativa L.) cultivars were crossed in all possible combination (excluding reciprocals) to assess the occurrence of heterosis in rice for grain yield and its components and to compare the hybrid performance of F1 and F2 generations for all traits studied under temperate conditions. The average heterosis and heterobeltiosis observed in F1 generation for grain yield per plant were 21.2% and 15.2%, respectively. Whereas, the average 8.2% heterosis and -0.2% heterobelthiosis were obtained in F2 generation for this trait. Heterosis for grain yield per plant in F1 generation was due to heterosis for the number of panicle per plant, biological yield, and harvest index. The correlations between F1 heterosis and F2 heterosis values and between F1 heterobeltiosis and F2 heterobelthiosis values indicate that the heterotic effects continued in F2 generation for days to heading, plant height, panicle length, the number of spikelets per panicle, biological yield, harvest index, 1000 grain weight, grain length. Heterosis and heterobeltiosis from F1 to F2 generation for all the traits were also observed.