Screening of green gram accessions against pulse beetle Callosobruchus chinensis (L.)

A total of 85 green gram [Vigna radiata (L.) Wilczek] accessions were screened under laboratory condition against pulse beetle Callosobruchus chinensis to identify sources of resistance. Accessions which exhibited lesser growth index (GI) during the preliminary ‘free choice’ test were further subjected to ‘force choice’ test for confirmation of resistance. No green gram accession was observed to be immune to bruchid, yet showed significant differences in terms of oviposition, developmental period, adult emergence and seed weight loss. Two accessions viz., KM-11-11 and KM-11-10 resulted in the least adult emergence (12.33 and 25.56% respectively), prolonged developmental period (31.77 and 30.30 days) and lesser growth index (0.034 and 0.046), respectively. The accession Pusa 0831 was observed to be susceptible with survival of 76.54%, developmental period of 23.33 days and growth index 0.081. Correlation between GI and other growth parameters of C. chinensis on the accessions indicated that GI was significantly positively correlated with adult emergence (r = 0.974) and weight loss (r = 0.954); however, developmental period (r =-0.982) was negatively correlated; and oviposition showed a non-significant positive correlation (r = 0.332). Hence, these accessions will be promising as donors for developing bruchid resistant varieties in green gram.