Quantification of Cry1Ac protein at different stages of plant growth in cotton (Gossypium hirsutum L.)

The present study was conducted at Central Cotton Research Institute, Multan, Pakistan during cotton growing season 2009-10. Nine cotton cultivars with Cry 1 Ac gene (Mon 531 event) selected for current experiment to characterize the toxin level of Cry1Ac protein in different Bt cotton cultivars and to record the variation in Cry1Ac protein at various plant growth stages. It was found that age of plant was having an influence on the expression of gene. Maximum level of endotoxin (0.373 g/g) was observed in genotype CIM-595 at 100 days of planting. While minimum value (0.166 g/g) was observed in genotype V-1 at 160 days of planting. Similarly different cotton genotypes showed different boll worm damage % at different growth stages. CEMB-2 was found to be most susceptible genotype showing 93.33 % boll worm damage at 160 days after planting. While V-5 proved to be most resistant showing no boll worm damage at 70 and 100 days after planting.