Biochemical and morphological basis of resistance in okra (Abelmoschus esculentus (L.)) against whitefly and jassid

A major constraint in okra (Abelmoschus esculentus (L.)) production is damage caused by insect pests, whitefly and jassids, which results in low yield. Identification of resistant varieties is a convenient and eco-friendly way towards sustainable management of insect pests attacking okra. Therefore, population dynamics of the two major pests were recorded in fifteen hybrid varieties of okra during two consecutive years in 2019 and 2020. Plant varietal resistance and vigor were also evaluated in this study. Meanwhile, morphological parameters were also recorded as well as whitefly and jassid-infested and healthy leaves were collected for biochemical analysis. Significant varietal difference in terms of insect infestation were recorded with Kajari NOH-1684, Japani jhar, Singham and Rohini being comparatively resistant varieties. Correlation studies revealed significant negative correlation of whitefly and jassid population with hair density, hair length and total phenols; positive correlation with total protein and total sugar content. The comparative analysis of superoxide dismutase and peroxidase activity revealed varieties more susceptible to whitefly and jassid attack resulted in higher enzyme activity in all the growth stages. The genotypes Kajari NOH-1684, Japani jhar, Singham and Rohini exhibit low infestations of whitefly and jassid, suggesting a tolerance based on their antixenotic properties. To enhance tolerance against these sucking pests, it is recommended to introduce the donor parents Kajari NOH-1684, Japani jhar, Singham and Rohini into okra breeding programs.