Response of maize hybrids exposed to drought and heat stress under field conditions

Abstract

Maize (Zea mays L.) is susceptible to abiotic stresses which reduce crop yields drastically. This study investigated the morpho-physiological responses of quality protein maize genotypes under optimum and combined drought and heat stress (CDHS) conditions. The experiment was laid out in a 5 x 5 alpha lattice incomplete block design with three replicates. Plant height (PH), ear height (EH), ears per plant (EPP), days to 50% anthesis (DT), days to 50% silking (DS), anthesis-silking interval (ASI), canopy temperature (CT), chlorophyll content (CC), number of rows per ear (NRE), cob length (CL) and grain yield (GY) traits were recorded. Results showed significant (p < 0.05) genetic variability among hybrids for all traits. The environment significantly (p < 0.05) influenced most traits, CDHS caused a decrease in all traits except ASI, CC, EPP and NRE. Combined stress significantly increased CT and delayed DT and DS of some hybrids. Yield loss due to stress ranged between 10% to 70%, with some hybrids (QPM 3; QPM 6; QPM 8, QPM 10; QPM 13, QPM 17, QPM 18) outperforming the drought tolerant check, ZM1523. The environment × genotype interaction significantly (p < 0.05) differed for all traits except CC and NRE.