Abstract
Drought is a major constraint in grain production of bread wheat. Drought tolerant Pakistani line Chakawal-50 and drought
susceptible line 9436 was crossed to develop F1, F2 and backcross generations. Genetic analysis was conducted for different
traits (Stomatal conductance, photosynthetic rate, excised leaf water loss, relative water content, plant height, number of grains
per spike and grain yield per plant). Presence of additive, dominance and epistatic components were identified for all traits
under study. Gene action was found complex in nature except for plant height. Selection should be done in later generations
for improvement of traits with complex gene action. Where selection in early generations was suggested due to significant
additive component for plant height. Number of grains per spike showed medium while remaining traits showed high broad
sense heritability. Number of grains per spike and stomatal conductance showed low while remaining traits showed medium
narrow sense heritability. Relative water contents and number of grains per spike showed high while remaining traits showed
low genetic advance. It was also suggested that selection in F2 and succeeding populations for variety development would
result in improvement of all traits except for excised leaf water loss and plant height. In these traits hybrid breeding was
suggested due to high heritability and low genetic advance.
