Leaf-mediated response of soybean genotypes to infestation by whitefly, Bemisia tabaci (Gennadius)

Abstract

Abstract The whitefly, Bemisia tabaci (Gennadius) is documented as a major pest on soybean. It was reported that whitefly response towards its hosts and their cultivars varies, and is mediated through various host-related factors. Considering the significance of leaf morphological characteristics in influencing the host–whitefly responses, the present investigation was conducted in screen-house conditions to study the prevailing variations in leaf morphological characteristics of soybean genotypes and their role in governing the adult whitefly attractiveness and oviposition preference. In the multiple-choice test, the whitefly population (eggs, nymphs and adults) was found to be lowest in moderately resistant genotypes (SL 1028 and SL 1074) compared to highly susceptible (DS 3105) and susceptible genotypes (SL 688, SL 958 and SL 1113). The foliar trichomes were characterized using scanning electron microscopy and leaf area, leaf lamina thickness and leaf shape data were acquired using standard procedures. To determine the factors involved in the resistance/susceptible responses towards whitefly, Pearson correlation was applied between the morphological characteristics and the whitefly population. The results show that the leaf area, trichome density, trichome length and trichome angle showed a significant positive correlation with the whitefly population, whereas leaf lamina thickness was negatively correlated. Thus, for developing whitefly-resistant germplasm, breeders should choose genotypes having narrow and thick leaves with sparse, short and flat trichomes.