Physical basis of resistance in wild Lens spp. accessions to pulse beetle, Callosobruchus chinensis
Laboratory studies were conducted on 51 accessions of different Lens spp. viz., L. culinaris (cultivated), L. culinaris subsp. odemensis, L. culinaris subsp. orientalis, L. orientalis, L. nigricans, L. lamottei and L. ervoides (wild species) for their reaction to pulse beetle, Callosobruchus chinensis. These accessions, varying in their physical seed parameters (both quantitative and qualitative), exhibited differential reactions to infestation by the beetle. Therefore, these parameters were evaluated to understand the physical basis of resistance against C. chinensis under no-choice artificial infestation conditions. Physical seed parameters of different accessions viz., length × width, test weight, seed moisture content, seed coat colour, cotyledon colour and testa pattern compared with growth index (GI) of C. chinensis revealed significant intra-and interspecific variations among the accessions of different Lens species. Correlation coefficients between growth index of C. chinensis and physical parameters of Lens spp. accessions indicated that GI of C. chinensis had significant positive relation with length × width, test weight and seed moisture content indicating that small seeds with low seed moisture conferred resistance to C. chinensis and the seed coat colours greyed-green and brown were least preferred by C. chinensis.