Genetic analysis of variability and trait association in tropical field corn (Zea mays L.)

Abstract

Grain yield is a complex trait influenced by environment and yield components. Hence, the information on the extent of variability in different traits and on association of yield with its components is useful for breeding for higher yield. Present study was carried out to investigate the nature and magnitude of genetic variability, heritability, genotypic and phenotypic correlations among grain yield components and their direct and indirect effects on grain yield of maize in two seasonskharif and rabi. In kharif, a total of 170 genotypes (54 lines, 2 testers, 108 single cross hybrids and 6 checks) and in rabi 110 genotypes (34 lines, 2 testers, 68 single cross hybrids and 6 checks) were evaluated in latice design. The analysis of variance revealed significant mean sum squares due to genotypes for all the traits implying the existence of sufficient genetic variability among the inbreds. The presence of variability for various traits was also revealed by Phenotypic and Genotypic Coefficient of Variation (GCV and PCV) for different traits. Grain yield recorded GCV and PCV of 39.81 & 25.89% and 40.41 & 28.72% during kharif and rabi, respectively. Hence, there is possibility of selection of inbreds with higher performance for various traits. Correlation analysis revealed significant positive genotypic correlation (p = 0.01) of yield with plant height (rg = 0.97 and 0.83), ear height (rg = 0.98 and 0.82), cob length (rg = 0.91 and 0.71) and number of kernels per row (rg = 0.94 and 0.73) during kharif and rabi, respectively. The results of path coefficient analysis revealed that most of the characters studied had positive direct effects on grain yield. During kharif cob length (2.028), kernel row number (0.341) and hundred seed weight (0.126) had positive direct effect on grain yield. In rabi, cob width (0.578) had maximum direct effect on grain yield followed by ear height (0.461), cob length (0.412), and plant height (0.146). The results of variability analysis read with the results of trait association implied that there is possibility of improvement of yield and yield components in the material studied and the significant positive association meant that combination of traits could be improved simultaneously.