Abstract

Nine (Bacillus thuringiensis) Bt genotypes (Bts-496, FH-113, CP-1401, I-2015, I-2086, CP-1402, VH-255, MG-3 and I-802) and non-transgenic genotype CIM-496 (control), were sown in an RCBD with a plot size of 206 x 170 ft to determine the correlation of abiotic factors and physico-morphic characters of Bt cottons with whitefly, Bemisia tabaci (Homoptra: Aleyrodidae) and jassid, Amrasca devastans(Homoptera: Jassidae), populations. The results suggest that maximum population of the whitefly and jassid was observed on transgenic genotypes VH-255 and I-2086, respectively; while, the lowest population was recorded on control. The results, showed whitefly and jassid populations to be positively correlated with the temperature. The correlation between the relative humidity was found to be negative for both the whitefly and jassids. The rainfall had a positive effect on the whitefly and negative effect on the jassids. The effect of physico-morphic characteristics of transgenic and non-transgenic varieties had similar kind of varied relationship with the whitefly and jassids. For example, the trichome-density on the leaf-lamina, midrib and veins had positive and significant correlation with the whitefly. In contrast, it is non-significant and negatively correlated with the jassids population. The varieties having thick leaf lamina showed non-significant negative response for the whiteflies population, and significant positive correlation with the jassids.

Key words: Cotton, Bemisia tabaci, Amrasca devastans; abiotic factors, physico-morphic plant chararters.