Biochemical mechanism of resistance to shoot fly, Atherigona approximata Malloch in foxtail millet (Setaria italica L.)

Abstract

Shoot fly (A. approximata) is one of the major insect pests of foxtail millet and host plant resistance is an important factor in reducing the damage caused by this pest. A better understanding of the mechanism of resistance in foxtail millet against shoot fly would help in developing the resistant varieties. In the present study, biochemical (total and reducing sugars, total phenols, total free amino acids, tannins and crude proteins content) parameters and major nutrients viz., N, P, K were analysed in the 10 selected foxtail millet genotypes representing each resistance category. The study revealed that higher amount of crude proteins, total soluble sugars, total reducing sugars, nitrogen and phosphorous were present in susceptible genotypes compared to resistant genotypes. The amount of phenols, tannins, total free amino acids and potassium in all resistant genotypes were found higher compared to susceptible genotypes. Significant positive correlation was observed between A. approximata damage and crude proteins (r= 0.87**), total soluble sugars (r= 0.84**), total reducing sugars (r= 0.93**), nitrogen (r= 0.87**) and phosphorous (r= 0.95**). While, total phenols (r= -0.92**), tannins (r= -0.91**), total free amino acids (r= -0.92**) and potassium (r= -0.83**) showed a significant negative association with shoot fly infestation. These biochemical components in foxtail millet can be used effectively in the breeding program to develop resistant varieties against A. approximata.