Resistance to the maize Weevil (Sitophilus zeamais Motsch) among Maize Inbred Lines

Maize is a very important crop for small-scale farmers in Africa and also as food and feed resource. Despite this, storage pests cause high quality and quantity losses to the crop. One of the most important storage pests of maize is the maize weevil (Sitophilus zeamais Motsch.). It is recognised that management of this pest can only be sustainably achieved through growing resistant genotypes. This study was therefore initiated to identify inbred lines resistant to the maize weevil for use in hybrid maize breeding. One hundred and twenty inbred lines were crossed in an alpha lattice design with two rows of 2 x 5 m and replicated thrice in the field at two locations; Kiboko and Embu in Kenya) for two seasons in 2010 and 2011. After harvest 100g grain samples infested with 50 unsexed newly reared insects were incubated for 3 months in jars. After 3 months, grain weight loss (%), number of adult progeny, and flour production (%) were assessed for each jar. Data for individual and combined locations were analysed. Differences in inbred lines were highly significant (P <0.05) for maize weevil progeny emergence, grain weight loss and the flour weight. Based on grain weight loss, genotypes were categorised into resistant, moderately resistant, moderately susceptible, susceptible and highly susceptible. Genetic diversity for maize weevil resistance thus exists among tropical maize inbred lines. This offers an opportunity to exploit tropical germplasm to breed for weevil resistance and reduce post-harvest storage losses in maize.