Abstract
Seedlings of 50 varieties/lines of Gossypium hirsutum were screened for water stress tolerance during 2010-2013. Indices of water stress tolerance were calculated on the basis of shoot and root lengths. Based on similarities and differences, CIM-496, 149F, DPL-26, BOU-1724 and B-557 were found tolerant to moisture stress, whilst FH-1000, NF-801-2-37, MNH-129 and H-499 exhibited susceptibility to water stress. Results of screening revealed that variability among germplasm was present which may be exploited through hybridization. Therefore, F-1 crosses were developed in the field keeping stress tolerant genotypes as lines and susceptible as testers using line x tester technique. The genetic material developed was field-planted and 50% moisture stress was applied to examine responses in plant height and seed cotton yield. The analysis of F1 and parental data revealed the preponderance of non-additive genetic effects for both traits. Testers and interaction between parents contributed more to expression of plant height and seed cotton yield respectively. CIM-496 with significant and positive general combining ability estimates, i.e. 1.83 for plant height and 3.65 for seed cotton yield was found to be good general combiner for both the traits. The cross B-557 x H-499 was the best varietal combination for plant height and seed cotton yield. Non-additive variation for both traits suggests possibility of using this material for hybrid development in drought hit areas. Plant height did not significantly affect seed cotton yield as shown by non-significant correlation coefficient (0.3).