The Effects of Genotype, Soil Water Deficit and Their Interaction on Agronomic, Physiologic and Yield Traits of Zea mays L.

The presence of genotypic differences in performances under soil water deficit would help plant breeders in initiating successful breeding programs to improve drought tolerance. The objectives of the present study were: (i) to assess the effects of genotype, water stress and their interaction on maize agronomic, physiologic and yield traits and (ii) to identify drought tolerant genotypes for use in future breeding programs. Fifteen commercial hybrids and seven breeding populations were evaluated in the field for two seasons under water stress at flowering (WSF) and grain filling (WSG) compared to well watering (WW). A split plot design with three replications was used. Data analysed across seasons revealed a significant reduction in grain yield/plant (28.69 and 20.26%), grain yield/ha (35.53 and 25.51%), chlorophyll concentration index (30.18 and 44.07%) and 100-kernel weight (6.75 and 12.36%) due to water stress under WSF and WSG, respectively, a significant reduction in ears/plant (11.58%), kernels/row (14.23%), kernels/plant (24.85%) due to water stress under WSF and in upper stem diameter (18.46%) due to water stress under WSG, but a significant increase in days to silking (3.50%), anthesis silking interval (21.17%) and barren stalks (26.18%) due to water stress under WSF. Rank of genotypes differed from one irrigation regime to another for most studied traits. The highest yielding genotypes were Eg-77, P-3444, SC-128 and HT-2066 under WSF and P-3444, SC-128, TWC-324 and SC-166 under WSG, in a descending order. These genotypes could be offered to maize breeding programs for developing drought tolerant inbred and hybrids.