Biochemical basis of resistance to whitefly Bemisia tabaci Geno. (Aleyrodidae: Hemiptera) in cotton

Abstract

To determine the relationship of biochemical constituents of leaves with whitefly Bemisia tabaci Genn., sixteen cotton cultivars were tested under screen-house conditions. The incidence of whitefly (adults/ nymphs/eggs) was recorded and correlations between the population densities and the content of biochemical constituents of cotton during the vegetative and reproductive stage were calculated. Total sugars, tannins, flavonols, phenols, o-dihydroxyphenols and gossypol were found negatively correlated with the population density of whitefly. The correlation coefficients between nymphal population and tannin content and between egg and tannin were -0.5179 (P = 0.05) and -0.7543 (P = 0.01), respectively. Cultivars having greater total phenolic and o-dihydroxyphenolic contents in leaves supported fewer whitefly eggs (r was -0.6670, P = 0.01 and -0.5863, P = 0.05), respectively.