Genetic variability among exotic and indigenous maize inbreds for resistance to stored grain weevil (Sitophilus oryzae L.) infestation

Sitophilus oryzae is one of the most important stored grain pests of maize causing substantial losses. Owing to high cost, environmental and health hazards, chemical control does not provide an acceptable solution. Host plant resistance offers sustainable and cost-effective way to reduce the losses. A set of 162 diverse inbreds were evaluated to assess their responses to infestation of S. oryzae. Significant variation for (1) grain weight loss (GWL) (4.19–42.32%), (2) emergence of insect progeny (5.67–75.67), (3) germination of infested seeds (GIS) (0.00–81.33%), (4) pericarp thickness (PT) of the grain (47.32–194.83 μm) and (5) grain hardness (GH) (113.00–1,171.67 Newton) was observed among inbreds. GWL and emergence of insect progeny were positively correlated, while GIS was negatively correlated with both. PT and GH did not show any association with other characters. CML442 and CM394 earlier reported to be promising against S. zeamais, were also identified as resistant to S. oryzae. SKV21, Pant109, Pant124, MGB1, CML207 and LM13 were identified as resistant inbreds. These inbreds can potentially serve as valuable donors in the resistance breeding programme. The resistant inbreds can also be crossed with diverse susceptible inbreds to generate mapping populations for identifying QTLs conferring resistance to S. oryzae.