Evaluation of physio-biochemical criteria in maize inbred lines and their F1 hybrids grown under water-deficit conditions

Abstract

Since the application of deficit water became a dominant tactic in crop irrigation, developing and surveying newly adapted genotypes should be adopted. In this study, we determined the physio-biochemical activities of 21 maize genotypes under 100 % and 70 % crop evapotranspiration irrigation conditions (normal and deficit irrigation, respectively) in sandy soil to determine which activities can identify drought-tolerant, high-yield genotypes. The experimental design was arranged in randomized complete blocks with three replicates. Results showed that the drought-tolerant parents and hybrids had the highest relative water content (RWC), membrane stability index (MSI), chlorophyll a and b (Chl. a, b), total chlorophyll (total Chl.), chlorophyll a/b ratio (Chl. a/b), chlorophyll stability index (CSI), proline, phenolic content, superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) levels. They also had the lowest malondialdehyde (MDA) content. The physio-biochemical traits were positively correlated with more tolerant inbred lines and hybrids that displayed a high yield under both irrigation treatments. Furthermore, maize parents that performed well under the 100 % and 70 % evapotranspiration levels were capable of producing high-performance hybrids under both conditions. Accordingly, the hybrids P1 x P6, P2 x P5, and P4 x P6 gave a high performance in sandy soil under both conditions, based on yield attributes estimation. It could be concluded that physio-biochemical traits can be used as effective selection criteria at the silking stage of maize plants to identify high-yield inbred lines and hybrids under stress and normal conditions. These findings will undoubtedly aid maize breeders in rapidly improving and developing new drought-tolerant varieties.