EFFECT OF PHYSICO-MORPHIC CHARACTERS ON POPULATION OF WHITEFLY BEMISIA TABACI IN TRANSGENIC COTTON

We examined the effect of physico-morphological characters on whitefly Bemisia tabaci population in transgenic cotton at University of Agriculture Faisalabad research area with available genotypes. Physico-morphological characters such as number of gossypol glands, trichome density count, trichome length, moisture contents (%) in leaves, and thickness of leaf lamina was correlated with whitefly population. The maximum trichome’s length on leaf vein was recorded to be 4.73/cm on the leaves of genotype Bt-2016 and differed significantly from those of observed on the leaves of all other genotypes. The maximum moisture percentage in the leaves was recorded to be 78.85% in FH-114 and did not differ significantly from those observed in Bt-2086 and BT-802 with 77.54 and 76.47 percent moisture contents in their leaves, respectively. The maximum trichome’s density was recorded to be 490.96/cm on leaf midrib of Bt-2016 and showed significant variation from those of observed in all other genotypes. The genotype FH-113 possessed maximum number of gossypol glands i.e. 43.55/cm on leaf midrib and differed significantly from those of observed in all other genotypes. The maximum thickness of leaf lamina was recorded to be 1.97 mm on genotype BT-2086 and showed significant difference from those found on all other genotypes. The results revealed that hair density on midrib and vein, gossypol glands on midrib, vein and lamina and moisture percentage in the leaves showed significant and positive correlation with the population of whitefly. Hair length and thickness of leaf lamina exerted negative and significant effect on the pest population.