Assessment of differential reaction of wild Vigna germplasm to pulse beetle, Callosobruchus chinensis (L.)
Chethan Kumar KB, Kuldeep Tripathi, Padmavati G Gore, BR Vinod, Arjuna Subhash and Kavita Gupta
The yield potential of Vigna species is not achieved due to several obstacles in production and storage like insect-pests, diseases etc. Among insect-pests, pulse beetle (Callosobruchus chinensis L.) causes major losses. In present study, 21 wild Vigna accessions and 2 checks (cowpea) were evaluated for their reaction to pulse beetles under ‘no choice’ artificial infestation conditions. Significant variations among the accessions were observed for various growth parameters of C. chinensis viz., oviposition, development period, adult emergence, number of emergence holes, weight loss, and growth index (GI). Based on growth index, the wild accessions were categorized as highly resistant (IC553547, GI=0.149-1.249), resistant (9 accessions, GI=1.249-2.349), moderately susceptible (11 accessions, GI=2.349-3.449), susceptible (0 accessions, GI=3.449-4.549) and highly susceptible (0 accessions, GI=4.549-5.649) to attack of C. chinensis. Of the 2 checks, PL04 was found to be susceptible and RC101 was found highly susceptible. Correlation studies showed that, the major trait GI was negatively related with mean development period (r = -0.03), and significantly positively related to adult emergence (r = +0.94). Regression, biplots, dendrogram and principal component analysis (PCA) were performed to assess the association and reaction of seed and insect growth parameters. Three principal components contributed 92.5% variability in PCA research. The worked 23 accessions have been grouped into three major clusters according to the resistance reaction of the accessions. The highly resistant accessions identified in this study based on key traits viz., GI and seed weight loss can be used for introgression of bruchid resistance into agronomically superior cultivated Vigna cultivars.
