Study on combining ability, heterosis and genetic parameters of yield traits in rice

Abstract

A study was conducted on heterosis, combining ability and genetic parameters of yield and yield components in rice. Five lines were crossed with two testers in line × tester manner to produce ten F 1 hybrids. Results show that general combining ability (GCA) effect was only significant for total number of kernels per panicle, number of filled kernels and grain yield per plant, and specific combining ability (SCA) effect was significant for yield and all of its studied components (except for 100-kernel weight). Lines IR42 and Pouya showed a significant GCA for grain yield in opposite direction (20.9 and-13.7 g/plant, respectively). The two lines also showed highest significant GCA for number of filled kernels (22.7 and 23.3, respectively). In the total number of kernels, lines IR8 and IR42 and tester Usen showed the highest significant GCA (34.79, 27.97 and 12.56). In tiller number, only line IR36 and tester IR68897 had the highest significant GCA (3.51 and 0.84). Combination of IR68897×IR8 showed highest significant SCA for grain yield (9.7 g/plant), while in the case of number of filled kernels and tiller number, combinations IR68897×IR8 and Usen/IR36 showed a significant positive SCA (18.9 and 2.1, respectively), indicating that hybridization can be a choice for improving hybrids with better quantity of these traits. The highest general heritability (2 b h) was obtained for tiller number (96.1%), indicating slight effects of the environment on the trait, while for other traits, a mild general heritability (~70%) was obtained, indicating considerable effect of environment on phenotypic expression of most yield traits. A low specific heritability (2 n h) was obtained for all traits (18.2 to 26.3%), indicating that non-additive effects play an important role in genetic control of yield traits. Therefore, it seems that hybridization must be a choice for utilizing the putative heterosis in special crosses, and such a condition was observed for tiller number and grain yield in combinations of IR42×IR68897 and IR42×Usen.

Combining Ability and Heterosis for Agronomic and Yield Traits in Indica and Japonica Rice Crosses

“…The hybrids K 2 -54 × Basmati 370, K 2 -9 × Komboka and K 2 -9 × PAN 84 had high parent heterosis for filled grains per panicle while K 2 -8 × Basmati 370 and K 2 -8 × 08FAN 10 had negative heterosis. These results are contrary to the findings of Mirarab et al (2011) who reported non-significant heterobeltiosis for filled grains per panicle. Positive heterobeltiosis in the hybrid IR58025A × IET18648 (49.73%) and standard heterosis of 141.1% over the check variety TTB404 for filled grains panicle -1 was reported (Tiwari et al, 2011;Borah et al, 2017).…”

“…The parental lines such as Basmati 370, Basmati 217, PAN 84 and Komboka exhibited high and positive GCA effects for panicle length, flag leaf length, number of tillers plant -1 , number of spikelet's panicle -1 , number of panicles plant -1 and number of filled grains panicle -1 suggesting their desirability for improvement of positive agronomic and yield traits because they contributed to high grain yield, in contrast parents with low and negative GCA estimates (NERICA 1, PAN 84, K 2 -9, Dourado precoce and K 2 -54) are preferred for improvement of negative traits of grain yield such as plant height, 50% days to flowering and days to maturity. Previous studies reported the significance of using parents with high and positive GCA effects for the improvement of positive agronomic traits (Mirarab et al, 2011;Raju et al, 2014;Malemba et al, 2017). This study revealed high GCA variances for most of the yield traits studied.…”

“…In this study, high parent heterosis for effective tillers was observed in 16 F 1 hybrids suggesting that these F 1 hybrids had high number of effective tillers and thus possessed high yield potential. Previous studies reported high parent heterosis for number of tillers in F 1 rice hybrids (Mirarab et al, 2011;Dwivedi & Pandey, 2012;Borah et al, 2017).…”

“…The combining ability analysis revealed significant GCA and SCA variance for most of the agronomic characters studied suggesting the importance of both additive and non-additive gene actions in the expression of the yield traits. Previous studies reported the significance of both additive and non-additive gene action in the expression of agronomic and yield traits (Thakare et al, 2009;Mirarab et al, 2011;Padmavathi et al, 2012;Dar et al, 2014 andMalemba et al, 2017). The rice parents such as Basmati 370, Basmati 217, K2-54 and Komboka had high and positive GCA effects for grain yield suggesting that these parental genotypes were good general combiners for grain yield.…”

“…This study revealed high GCA variances for most of the yield traits studied. Mirarab et al (2011) conducted a study on heterosis, combining ability and genetic parameters of yield and yield components in rice. They reported that GCA was only significant for total number of kernels per panicle, number of filled grains and grain yield per plant implying that additive gene action was predominant in the control of these traits.…”