A Technique for Identification of Intrinsic Resistance of Maize Varieties to Sitophilus Zeamais (Motsch.) (Coleoptera: Curculionidae) Infestations

Abstract

A new technique used to identify resistant maize varieties to the maize weevil, Sitophilus zeamais (Motsch.) infestations is presented. It applies Sodium Dodecyl Sulphate- Polyacrylamide Gel Electrophoresis (SDS - PAGE) of the insect fat body to determine the levels of fat body vitellogenin (FVg) in the vitellogenic S. zeamais females which were reared on different maize varieties. Results on levels of FVg varied and ranged from 83.33% to 43.33% in insects raised in different varieties ANOVA of FVg, maize weight loss and F1 numbers showed significant differences among the varieties at P<0.05. Maize weight loss and F1 numbers were positively correlated with FVg, r = 0.74 and 0.98, P< 0.05. The revealed amounts of FVg in S. zeamais obtained from the varieties indicated varying intrinsic resistance of the varieties to the insect pest. The varieties exhibited resistance in descending order: ZM 621>H 622> H 511> Situka 1> Situka M1 > ZM 523. In conclusion SDS – PAGE of female S. zeamais fat body is hence a useful and robust technique for identification of the intrinsic resistance of maize varieties to S. zeamais infestations.

Key words: Technique, Fat body, Vitellogenin, Maize resistance, S. zeamais