Rhyzopertha dominica (Coleoptera: Bostrychidae): Studies on screening techniques of wheat genotypes/varieties for resistance

Abstract

Lesser grain borer, R. dominica (Coleoptera: Bostrychidae) is a notorious insect pest of wheat and it can cause both quantitative and qualitative losses and also decrease the sustenance of stored wheat. The host preference of R. dominica were studied in twenty five wheat genotypes/varieties with both free and force choice test. Free choice screening provided prefatory information which was antixenosis usually measured. In force choice’s per cent weight loss, F1 adult emergence and susceptibility index demonstrated the rapid increases in the R. dominica population in wheat variety GW 190 compared than wheat genotypes/varieties VD18-12, VD18-13, VD18-14 and LOK1. Based on per cent weight loss, the genotype/varieties were graded by arbitary categorization as resistant (9), moderately resistant (6), less susceptible (5), moderately susceptible (3), and susceptible (2). Correlation done between the weight loss and all other growth parameters revealed that the weight loss has positive and significant correlation with mean developmental period and highly significant and positive correlation with F1 adult emergence and susceptibility index. The wheat genotypes/varieties resistant to R. dominica VD18-12, VD18-13, VD18-14 and LOK1 have the potential to reducing the loss of wheat during storage condition and it can also used as donor lines for future breeding purpose.