Relationship between physical and chemical characteristics and susceptibility to Zabrotes subfasciatus (Boh.) (Coleoptera:Bruchidae) and Acanthoscelides obtectus (Say) in common bean ( Phaseolus vulgaris L.) varieties

Abstract

Seeds of 17 common bean cultivars were characterized for resistance to infestation by Zabrotes subfasciatus and Acanthoscelides obtectus under no-choice and free-choice conditions. To determine the relationship of some physical and chemical characteristics of the seeds and resistance to bean weevils, seed hardness, seed coat thickness, tannins, lectins, trypsin inhibitors and protein content were evaluated in the 17 cultivars. Three of the cultivars were resistant to Z. subfasciatus, but none were resistant to A. obtectus. A correlation was found between lectin content and both oviposition (r = − 0.38, P < 0.05) and adult emergence (r = − 0.33, P < 0.01) in a no-choice experiment with Z. subfasciatus, confirming the importance of lectins for resistance against bean weevil. No correlations were found with seed hardness, seed coat thickness, tannins, trypsin inhibitors or protein content. The cultivars resistant to Z. subfasciatus were: Bayocel-1, Flor de Mayo Bajío and Bayo Victoria. Cultivar Bayocel 1 showed intermediate values of seed hardness and lectin content and high levels of seed coat thickness, tannins and trypsin inhibitors while Flor de Mayo Bajío showed the highest lectin content of all cultivars as well as high levels of seed coat thickness, tannin content and trypsin inhibitors. Bayo Victoria showed high levels of lectins and low levels of trypsin inhibitors.