Is “quality protein” maize more susceptible than normal cultivars to attack by the maize weevil Sitophilus zeamais?

Thirty-one quality protein maize (QPM) populations, pools or varieties were crossed with normal pollen (QPM × NOR) to provide two sets of maize for assessment of the effect of QPM conversion on susceptiblity to Sitophilus zeamais. The QPM maize showed a very high degree of variability from very resistant to very susceptible. The mean Dobie Index, which is a measure of susceptibility to insect attack, of the QPM group was not significantly different from that of the QPM × NOR. The mean number of egg plugs oviposited on maize samples of the two groups was not significantly different. Nine QPM populations or varieties were analysed for protein, tryptophan, oil and phenolic content. Susceptibility was found to be negatively correlated with oil content and phenolics, as has been found in normal maize. Since some QPM genotypes were resistant to weevil attack, the results suggest that it is possible to breed for both quality protein and insect resistance in the same maize cultivar.