EXPLORING THE GENETIC POTENTIAL OF MAIZE (ZEA MAYS L.) FOR HIGH-TEMPERATURE STRESS TOLERANCE

Abstract

Maize (Zea mays L.), a vital cereal crop, faces challenges from rising global temperatures. As a C4 plant, maize is highly heat sensitive, which disrupts photosynthesis and reduces growth and productivity. High temperatures during the reproductive phase delay silk emergence and dry pollen, decreasing seed production and yield. Developing heat-tolerant maize varieties is essential. Tolerance can be viable by utilizing genetic diversity in breeding programs. This study evaluated 156 inbred lines for high-temperature stress tolerance, selecting 56 promising lines. Their screening continued under field and screen house conditions. High-temperature stress significantly affected maize growth and reproductive stages, increasing the anthesis-silking interval and reducing flowering synchronization. Principal component analysis identified inbred lines PBG1(X), PBG2(X), PBG3(X), PBG4(X), PBG5(X), PBG7(X), 6200(X), 6201(X), 6205(X), and 6202(X) as the best performers under stress, while 6159(X), 6179(X), 6180(X), 6193(X), and 6199(X) performed poorly. Traits, such as cob diameter, days to silking, grains per cob, 100-grain weight, and leaf area, showed positive correlations with the anthesis-silking interval. Inversely, pollen production potential had a negative correlation, while the days to tasseling positively correlated with grain yield. These findings are crucial for developing heat-resilient maize varieties.