Heritability of drought adaptive traits and relationships with grain yield in maize grown under high plant population

Abstract

In low-moisture stress areas with unpredictable rain-free season, high-plant population is suggested for screening maize genotypes with tolerance to drought at flowering as alternative to stressed normal plant density. To confirm efficiency of this option, randomly derived 196 S1 lines from A-511 Maize Population were tested at two plant densities in combination with well watered and drought stressed at flowering. In each of the four environments, the S1 lines were grown in 14 x 14 alpha lattice experimental design to estimate: (i) broad-sense heritability of each tested trait; and (ii) relationships between grain yield and drought adaptive traits. The broad sense heritabilities of flowering traits were relatively high across all growing conditions. In contrast, the heritability for number of ears per plant (EPP) increased with increasing plant density and/or drought stress as for yield and most other traits decreased. Besides, significant association of grain yield with its components and flowering traits observed across all growing conditions in the same direction and opposite direction, respectively. Although relationships of yield with the drought adaptive traits increased consistently with increasing stress, it was highly dependent on its components in all environments but only under stress condition on anthesis-silking interval (ASI). In addition to significant expression of desirable parameters for a population improvement in the stress tolerance, ASI and EPP are relatively easily measured on field as compared to other drought adaptive traits. Thus, the strong dependence of yield on both traits and their high heritability in each or combination of the two stresses have confirmed possibility of using them for screening drought tolerant maize under high plant density, specially in areas that lack rain-free season.

Keywords: Drought adaptive trait, high plant density, heritability