Antinutritional factors in ricebean, Vigna umbellata Thunb. (Ohwi and Ohashi) against Callosobruchus maculatus F. (Coleoptera: Bruchidae)

Abstract

To identify some effective and eco-friendly inhibitors of a serious pest of pulse crops, Callosobruchus maculatus, seeds of 10 genotypes of rice bean, Vigna umbellata and mungbean variety, PAU 911 as susceptible check were screened. The different genotypes of rice bean were found to arrest the growth and development of C. maculatus at grub stages in varying levels. To confirm these results, the seeds of different test genotypes were analysed for the presence of three antinutritional factors (tannins, phytic acid and saponins). The amount of tannins, phytic acid and saponins was recorded highest in rice bean genotype LRB 507 (11.12 mg g−1), LRB 482 (32.30 mg g−1) and LRB 535 (4.17 mg g−1), respectively whereas lowest in mungbean variety, PAU 911 (8.24, 13.51 and 1.12 mg g−1, respectively). These antinutritional factors showed a negative correlation with adult emergence, growth index and adult longevity of C. maculatus but positive correlation with development period. Based on the results of the present study, all the rice bean genotypes were identified as resistant to C. maculatus as compared to susceptible check variety, PAU 911. The role of antinutritional factors in relation to C. maculatus infestation is discussed.