Morpho-biochemical responses of rice genotypes against leaffolder, Cnaphalocrocis medinalis, Guenee

Abstract

Abstract Rice leaffolder, Cnaphalocrocis medinalis, Guenee is a serious pest of rice and causes significant yield losses. Insecticides are commonly employed to control this pest, but their use often escalates production costs and fosters pesticide resistance. Identifying insect-resistant rice genotypes and their resistance mechanisms is crucial for successful pest management. New sources of resistance providing long-lasting protection against leaffolder can be identified by studying the morphobiochemical characteristics of different rice genotypes. This study explored the role of various morphological traits of certain genotypes that confer resistance. Different biochemical constituents like soluble protein, phenol, total soluble sugar and enzymes viz., peroxidase, polyphenol oxidase and catalase were assessed spectrophotometrically in all infested and uninfested genotypes along with standard resistant (TKM6) and susceptible (TN1) checks. Leaffolder damage was negatively significant with plant height and leaf length (r = -0.903 and − 0.862, P < 0.001 respectively) while leaf width association was significantly positive (r = 0.773, P < 0.001). Among the different plant metabolites analyzed, total soluble sugar and soluble protein showed significant positive correlation (r = 0.778 and 0.788, P < 0.001 respectively) with leaffolder damage, conversely phenol (r = -0.651, P < 0.001) and antioxidative enzymes showed significant negative correlation. When rice genotypes were exposed to leaffolder larval feeding, they exhibited defence responses characterized by reduction in the level of sugars and proteins, accumulation of phenolic compounds and upregulation of antioxidative enzymes. This study emphasized the significance of morphobiochemical characteristics in rice resistance mechanisms against leaffolder. By leveraging these traits, new resistant rice germplasms against leaffolder can be developed.