An abbreviated procedure to determine the inherent resistance of maize to Sitophilus zeamais Motsch. (Coleoptera: Curculionidae)

Several experiments on the influence of resistant and susceptible maize on developmental parameters of Sitophilus zeamais Motsch. suggested that the procedure to determine the Dobie index of susceptibility could be shortened by replacing progeny yield with the number of eggs laid per sample and days to mid-emergence (DME) with days to first emergence (DFE). Before experimental validation of the modified index, assumptions regarding homogeneity of variances for DFE, DME and days to last emergence (DLE), degree of association between eggs laid per sample of grain and total progeny yield and between DFE and DME, and β-estimators of host suitability were proven. When compared to the Dobie index, the modified index extended the scale for rating resistance and magnified the differences among maize types. The new index could save time and resources for breeding programs.