Evaluation of specialty corn inbreds for responses to stored grain weevil (Sitophilus oryzae L.) infestation

Abstract

Evaluation of a diverse set of 68 specialty corn inbreds (pop corn, sweet corn and QPM) against stored grain weevil (Sitophilus oryzae L.) revealed existence of wide genetic variations for grain weight loss (3.40-41.21%), number of insect progeny emerged (5.00-76.33), germination of seeds after infestation (0.00-81.33%), pericarp thickness (36.18-178.13 μm) and grain hardness (62.33-600.33 Newton). Pop corn inbreds recorded lowest mean grain weight loss (8.19%) and number of insect progeny emerged (9.23) with highest mean germination (78.28%). Grain weight loss and number of insect progeny emerged were positively correlated, while both showed negative correlation with germination percentage. Pericarp thickness and grain hardness could not contribute to confer resistance. Based on cumulative resistance index (CRI), pop corn inbreds were in general more resistant (mean CRI=1.84) to weevil infestation as compared to shrunken sweet corn (mean CRI=1.51), sugary sweet corn (mean CRI=1.26) and QPM (mean CRI=0.76) inbreds. However, resistant inbreds were also identified in sweet corn and QPM types that can be utilized effectively as donors in the resistance breeding programme. The contrasting inbreds could serve as rich genetic resources for unravelling the basis of resistance.