Susceptibility of pro-Vitamin A biofortified maize genotypes to Sitophilus zeamais (Mots) in Ghana

Abstract

Pro-Vitamin A Biofortified maize is one of the crops with the cheapest and most sustainable option for preventing Vitamin A deficiency in humans in Ghana. It is also a key energy component of feed for layer chicken, forming about 60-70% of the total feed. Sitophilus zeamais is one of the most serious primary internal feeding pests of maize and other grains in sub-Saharan Africa. It causes both quantitative and qualitative grain losses. Two no - choice laboratory experiments in 112 days cumulative feeding of S. zeamais and 60 days susceptibility of six pro-Vitamin A Biofortified Maize (PVABM) genotypes to the insect were conducted. The experimental designs were Completely Randomized Design in four replications. Percentage grain damage and weight loss were significantly lower (P<0.05) in Aburokokoo than the other genotypes. Significantly more S. zeamais emerged from Accession GH2354 which also had significant (P<0.05) higher percentage grain damage than other genotypes. In the 60-day susceptibility experiment, grain hardness had significant (P<0.05) negative correlation with F1 progeny, index of susceptibility and protein content but positive significant correlation with median development period. Large number of S. zeamais F1 progeny, high susceptibility index, high protein, low total carbohydrate content, short median development time with low grain hardness value were observed on accession GH2354. Aburokokoo had significantly (P<0.05) small number of F1 progeny, low index of susceptibility, low protein and high total carbohydrate, long development period and intermediate value of grain hardness. The ascending order of grain hardness among the maize genotypes was GH2354<Obatanpa <Aburokokoo<Abontem<Honampa<Ahoodzin. There was no relationship between grain length, width and thickness and grain susceptibility. A cluster dendrogram obtained from the maize genotypes with regard to resistance parameters to S. zeamais showed that accession GH2354 and Obatanpa-QPM were susceptible, Ahoodzin, Honampa and Abontem were moderately resistant, with Aburokokoo resistant to the maize weevil infestation. Key words: Biofortified maize, stored produce, insect pest, Vitamin A deficiency, grain damage