Estimation of drought effects on different bread wheat genotypes using morpho-physiological traits

The changing climatic condition of the world significantly affecting the average grain yield of wheat crop. In the present study, fifty-six wheat genotypes including checks (Akbar-2019 and Barani-2017) were tested under drought stress. The crop was grown under rainfed conditions (only pre-sowing irrigation was applied at the time of land preparation) following alpha lattice design with two replications at Wheat Research Institute, Faisalabad, Punjab, Pakistan during 2020-21. Several yield and yield contributing traits were examined under drought stress. The analysis of variance (ANOVA) depicted significant differences among all traits which showed existence of great variation among them. Pearson's correlation studies showed significant positive correlation of yield (kg ha(-1)) with spike length (0.98**), flag leaf area (0.97**), normalized difference vegetation index (NDVI) at booting (0.87**) and grain filling stage (0.97**). Similarly, bi-plot analysis also revealed association of yield (kg ha(-1)) with spike length (cm), flag leaf area (cm(2)), NDVI at booting and NDVI at grain filling stage under drought stress condition. Estimation of canopy temperature at grain filling stage expressed negative relationship with yield (-0.11) under drought stress. Genotypes V-19274 (4536.2 kg ha(-1)) and V-19177 (4450.5 kg ha(-1)) were found best regarding yield and its contributing traits (spike length and flag leaf area) under drought stress. Cluster analysis separated the wheat genotypes in to four groups. Among all clusters the group four expressed high magnitude of yield (5163.4 kg ha(-1)). The genotypes in this cluster expressed high magnitudes of spike length (15.18 cm), flag leaf area (64.03 cm(2)), grain filling period (40.5 days), NDVI at booting (0.81) and NDVI at grain filling stage (0.72), while showed lower magnitude regarding plant height (97 cm), days to 50% maturity (141.5), days to 50% heading (101) and canopy temperature at grain filling stage (21.55) as compared to other three clusters. The identified wheat genotypes can be further used in different wheat breeding programs for water deficient conditions in changing climate scenario of the region to develop drought tolerant wheat cultivars.