Genetic variation and trait association of maize hybrids under irrigated and drought-stress environments

Abstract

Drought stress is the principal cause of production losses in maize (Zea mays L.), especially in a rainfed ecosystem. Reducing the yield penalty of maize under stress conditions demands the development of hybrids with improved tolerance to drought stress. The extent of genetic variability and association among the traits over yield under irrigated and water stress conditions of  72 hybrids were studied. The analysis of variation reveaeds that significant variability was observed among the hybrids under stress conditions, which provides the scope for identifying drought-tolerant hybrids. The average yield reduction was 60.26 per cent under drought stress in this study and the ASI increased by 56.20 per cent. Under stress, high GCV was observed for ASI (36.74 %), plot yield (31.96 %), leaf rolling (29.65 %), leaf senescence (27.79 %) and ears per plant (24.40%) Furthermore, the traits such as plant height (0.95), leaf width (0.83), number of leaves (0.68), ear height (0.67), plot yield (0.64) and ears per plant (0.61) found to have high heritability under drought stress condition.. The correlation studies revealed that yield is harmonized positively with all the yield attributes and negatively associated with Anthesis silking interval (ASI). Moreover, path coefficient analysis suggests that ears per plant and number of kernels per row are the essential secondary traits exhibits high positive direct effect on yield. Thus, the consideration of traits with a significant effect on yield coupled with high heritability will be helpful in selecting a potential drought-tolerant hybrids. Keywords :  Maize, drought, heritability, yield, path coefficient