Development of transgenic cotton lines harboring a pesticidal gene (cry1Ab)

Each transgenic plant has its unique genetic architecture and level of expression. The present study was conducted to study each transgenic plant separately in order to develop pure transgenic lines to be further used in efficient cotton breeding programme. Earlier MNH-93 cultivar was transformed with the Bacillus thuringiensis (Bt) gene cry1Ab through Agrobacterium-mediated transformation method using mature cotton embryos as explants. Transformed plants obtained out of this transformation event were used to develop pure lines for five consecutive generations. The selection criteria contained confirmation of transgene through PCR and western dot blot, boll damage percentage, insect mortality percentage in lab bioassay with heliothis larvae, seed cotton yield (g), plant height (cm), number of monopodial branches per plant and number of sympodial branches per plant. All the characters were stably inherited in further generations. The expression of introduced genes was found to be variable; however it conferred protection against targeted insect pests. It was concluded that the transgenic pure lines are an excellent source of germplasm to be used in conventional breeding programme.