Combining ability and heterosis studies in high oil maize (Zea mays L.) genotypes
Devi, T.R.; Prodhan, H.S.
Indian Journal of Genetics and Plant Breeding 64(4): 323-324
Eighteen high-oil inbred lines of ICRISAT materials were mated with three inbred lines (testers) in 18x3 line x tester design during rabi 1999. The resulting 54 hybrids along with the 21 parents were grown during the kharif and rabi seasons at Kalyani, West Bengal, India. Observations were recorded for grain yield, days to silking, ear length, ear diameter, kernel rows per ear, 100-grain weight, embryo weight, oil content and starch content. The significant general combining ability (gca) variance and ratio of gamma 2D/ gamma 2A showed that additive gene action was predominant in the expression of grain yield, days to silking, ear length and kernel rows per ear. On the other hand, the significant specific combining ability (sca) variance and greater ratio of gamma 2D/ gamma 2A showed that non-additive gene action was more important for ear diameter, 100-grain weight, embryo weight, oil content and starch content. Perusal of gca effects revealed that among female inbreds, RHORYD was the best combiner for grain yield and grain weight, while ICRISAT-98376 was a good combiner for grain yield, ear length and ear diameter and ICRISAT-95935 for grain yield, ear length and kernel rows per ear. There was no best general combiner for oil content. Among the male parents, Iowa 2E.H.O was the best combiner for grain yield, ear length and kernel rows per ear. In terms of sca effects, ICRISAT-346 x FRD-73 for both oil content and grain yield, ICRISAT-98354 x Iowa 2E.H.O for grain yield, and ICRISAT-1849 x FRD-73 and RHORYD x Iowa 2E.H.O for oil content, were the best crosses.