Resistência de variedades de milho crioulo Zea mays L. à Sitophilus zeamais Mots. (Coleoptera: Curculionidae).

Abstract

The maize Zea mays L. originating in Central America and cultivated throughout Brazil, is of great economic importance due to its several uses, from food and animal feed to high-tech industry and the production of biofuels. Among the several issues regarding the production of this crop, pest insects stand out. The maize weevil, Sitophilus zeamais Mots. (Coleoptera: Curculionidae), it is an insect pest that may cause damage to grain production and stored grains. The resistance of maize seeds of creole and commercial varieties was evaluated regarding the attack of Sitophilus zeamais Mots. (Coleoptera: Curculionidae) under storage conditions. Grain samples of two creole varieties, Jabotão and Batité, and a commercial cultivar, Caatingueiro, were used to perform laboratory bioassays. The following parameters were evaluated: host preference in different maize varieties by free choice test, instantaneous rate of growth (ri) and loss of grain dry mass (%). The means comparison was performed by Tukey test at 5% of significance, using the SAS software package, version 9.0. Among the analysed materials by free choice test, the number of S. zeamais present in the commercial cultivar Caatingueiro, after 48 hours, was significantly higher than that found in the creole variety Batité. For the creole variety Jabotão, after 48 hours, the number of S. zeamais was significantly lower than those found in Caatingueiro cultivar and Batité variety. The instantaneous rate of growth (ri) of S. zeamais was positive for the different varieties after 60 days of storage. However, the creole variety Jabotão showed the highest rate of growth (ri = 0.024), differing significantly from the Caatingueiro cultivar ( ri = 0.009) and Batité (ri = 0.014), which did not differ from each other. Lower grain mass loss (%) was observed in the creole variety Batité (6.77 ± 0.74g) and in the commercial cultivar Caatingueiro (4.77 ± 1.65g) when compared to the creole variety Jabotão (17.87 ± 1.76g).