INTERACTIVE EFFECTS OF GENOTYPE AND WATER DEFICIT ON YIELD AND QUALITY TRAITS OF MAIZE INBRED LINES AND F1 DIALLEL CROSSES

Maize (Zea mays L.) is vulnerable to drought stress at flowering stage, which has a detrimental impact on yield characteristics. Drought tolerance is genotype dependent.  The present study was conducted to investigate the effects of Water Deficit Stress (WDS) at flowering stage, genotype and their interaction on some agronomic, physiologic, grain yield and quality traits of 8 maize inbred lines and their 28 diallel crosses and also attempt to identify the maize genotypes tolerant to WDS conditions. The parents and F1 crosses were evaluated in two seasons. A split plot design with three replications was used, where main plots were allotted to two irrigation treatments, i.e., Well Watering (WW) by giving all recommended irrigations and WDS by withholding the 4th and 5th irrigations, while sub plots were allotted to genotypes. Water deficit stress caused a significant decrease in grain yield/plant (32.3%), grain yield/ha (26.7%), ears/plant (30.6%), rows/ear (10.2%), kernels/row (9.3%), kernels/plant (43.8%), 100-kernel weight (19.9%), plant height (8.5%), ear height (11.9%), and chlorophyll concentration index (17.3%) and a significant increase in anthesis-silking interval (58.82 %), days to anthesis (4.29%), days to silking (6.40%), barren stalks (20.0%), and grain protein content (16.0%). On average, means across F1 crosses were higher than those across inbreds for all studied traits, except for grain protein content and days to 50% silking, where the opposite was true, under both WDS and WW conditions. The rank of inbreds and crosses for studied traits under WDS was changed from that under WW conditions. The reduction in grain yield/ha of inbred lines due to drought (37.36%) was generally higher than that in F1 hybrids (25.67%). It was possible to identify some inbreds and hybrids characterized by high yield and high tolerance to WDS conditions, which were recommended for use in breeding programs for improving drought tolerance in maize.