Effect of sorghum grain quality on progeny emergence of Sitophilus oryzae L. (Coleoptera: Curculionidae)

Abstract

In this study, twenty sorghum-Sorghum bicolor (L.) Moench germplasm lines had been evaluated for their resistance to the stored grain pest, Sitophilus oryzae (L.). Observations were made on grain damage and weight loss, inhibitory effect of gut α-amylases, adult mortality and progeny emergence. The results reveal that grain weight loss and α-amylase inhibitory effect are the most significant factors that influence the progeny emergence. The resistant germplasm line IS 920 exhibited minimum grain weight loss (8.2%) and maximum α-amylase inhibitory effect resulting in significantly lesser progeny emergence along with least grain damage (17%). The inhibitory effect of enzyme inhibitors isolated from sorghum, when examined on gut α-amylase, it was observed that amylase inhibitors inhibited S. oryzae α-amylases appreciably; maximum inhibition being for IS 920 (82.8%) indicating that these α-amylase inhibitors could be used in IPM. The two parameters viz., grain weight loss and α-amylase inhibitory effect could be relied upon for selecting the resistant genotypes against S. oryzae in sorghum.