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Cotton leaf curl virus is a major impediment for productivity of cotton particularly in areas of Punjab province. A set of 110 cotton genotypes including varieties, and advanced lines, (87 Bt, and 23 Non-Bt) were evaluated at experimental farm of Cotton Research Institute Multan during 2016-17, and explored comparative response of GMO (Bt.) and Non-GMO (Non-Bt.). cotton varieties against leaf curl disease, and seed cotton yield. Under highly tolerant group, CIM-598, PB-82, and FH-312 showed lowest disease index with values 2, 5 and 7, respectively. Among Bt. varieties, under tolerant group, were PB-83, PB-86, MNH-992, FH-242, and NIAB-2008 showed disease index with values 21. Whereas, for non-Bt., four varieties CIM-506, CIM-573, VH-281, and CIM- 473, were tolerant. Highly tolerant Bt. varieties have 7.4% higher seed cotton yield over Non-Bt varieties. Similarly, under tolerant and susceptible group of Bt. varieties produced 16.6%, and 2.6%, higher seed cotton yield over Non-Bt. cotton varieties, respectively. However, seed cotton yield difference between Bt. and Non. Bt. cotton varieties were statistically non-significant. Disease severity showed negative significant correlation with plant height, bolls plant-1. Whereas disease infestation percentage was positively correlated with plant height, monopodial branches plant-1, fruiting branches plant-1, seed mass and boll mass boll-1. Most of the fibre traits were significantly associated with disease severity. Thus, disease severity is more limiting factor affecting morphological and fibre quality traits. The derived information could be valuable to make future breeding strategy against leaf curl virus disease of cotton.
Keywords: Boll and seed mass; Correlation studies; Cotton leaf curl virus; Disease index; Seed cotton yield