Morpho-physiological and biochemical responses of cotton (Gossypium hirsutum L.) genotypes upon sucking insect-pest infestations

The effects of sucking insect-pests on the morpho-physiological and biochemical changes in the leaves of four cotton genotypes—Bio 100 BG-II and GCH-3 (highly tolerant); KDCHH-9810 BG-II and HS-6 (highly susceptible)—were examined. Compared to tolerant genotypes, susceptible genotypes showed a decrease in relative water content, specific leaf weight, leaf area, photosynthetic rate, and total chlorophyll content, with an increase in electrolyte leakage. Hydrogen peroxide and total soluble sugar content were higher in susceptible plants. In contrast, resistant plants had higher levels of total soluble protein, total phenolic content, gossypol content, tannin content, peroxidase activity, and polyphenol oxidase. The findings demonstrated that the Bio 100 BG-II and GCH-3 genotypes effectively offset the impact of sucking insect-pests by modifying the factors mentioned above. The KDCHH-9810 BG-II and HS-6 genotypes could not completely negate the effects of sucking insect-pests. Customized metabolites and total soluble protein are more efficient in protecting cotton plants from damage brought on by infestations of sucking insects and pests.