Physio-biochemical and molecular characterization of wheat cultivars (Triticum aestivum L.) under post-anthesis heat stress

Background Heat stress is one of the abiotic stresses that make wheat crops vulnerable, which significantly impacts crop production around the world. An increase in temperature during the reproductive phase (anthesis) beyond the optimal range of 15–20 °C leads to decreased crop production, poor quality of the grain, and altered physiological and biochemical processes. To study the association between high temperature and physio-biochemical traits under normal and late sown, a set of fifteen genotypes was utilized. Results Relative water content under high temperatures had an overall decrease of 8.7%. However, grain protein and malondialdehyde content were higher in the stressed conditions than in the control, with increases of 20.2% and 38.9%, respectively. Marker Xgwm67 , located on chromosome 5B, was found to be significantly associated with malondialdehyde content ( R 2 = 21%) and Xgwm570 , located on 6A, was closely linked to relative water content as well as grain protein content ( R 2 = 16%) revealed by regression analysis. The correlation matrix displays a positive association between the control and stressed condition by R 2 = 0.92, 0.82, and 0.53 in malondialdehyde, relative water content, and grain protein, respectively. However, there was a negative correlation between water content–malondialdehyde and malondialdehyde–grain protein, though there was only a 4% correlation between grain protein content (control) and relative water content (stressed). Based on the tolerance matrix, WH730 and RAJ4079 were heat tolerant, and DBW173 and HD3086 were sensitive. Conclusions These findings indicate that to identify tolerant genotypes, physiological and biochemical traits can be utilized as an alternate criterion, and these closely associated markers can be applied for improved late-planted wheat production through MAS. The breeding scheme and genome editing by recognizing novel genes through physio-biochemical parameters, marker-assisted selection, and prospective screening of tolerant genotypes are proclaimed by the study.