Forty seven sweet sorghum genotypes were evaluated for resistance to stem borer during kharif 2007 -2009. Principal component analysis (PCA) was performed considering five parameters viz., dead-hearts, stem, peduncle tunneling, exit holes/stalk, number of larvae/stalk. Two principal components (PCs) were extracted explaining a cumulative variation of 71.5%. PC1 explained 47.7% of the variation while PC2 explained 23.7% of variation. PC1 had the loadings for dead-hearts (0.85), stem tunneling (0.73), exit holes/stalk (0.87) whereas peduncle tunneling (0.82) and larvae/stalk (0.81) were loaded in PC2. PCA brought out three characters/variables viz. dead-hearts, stem tunneling and exit holes/stalk, as most important in explaining variability thus, aiding in deciding reaction to pest. Eleven genotypes viz., E 27, IS 18162, IS 18164, E 38, ICSV 700, ICSV 93046, NSSV 6, GGUB 50, IS 5353, KARS 95 and RSSV 9 were found resistant to stem borer, Chilo partellus.
Sweet sorghum, Chilo partellus, host plant resistance, artificial infestation
