SCREENING COWPEA GENOTYPES FOR RESISTANCE TO STORAGE INSECT (Callosobruchus maculatus) AND DETERMINATION OF MARKETING STRATEGIES FOR SEED IN GHANA
ABSTRACT:
This study was conducted to screen cowpea genotypes for resistance to cowpea weevil Callosobruchus maculatus and to determine the seed marketing strategies in Ghana. Thirty-three genotypes from Burkina Faso, Ghana, Mali, Niger, Nigeria, and South Sudan were exposed to 0-24 day old adult weevils under laboratory conditions of 25±2°C and 70±5% RH, and the experimental design was Complete Randomized Design (CRD) with three replications. Data on adult mortality, reproductive efficiency, seed damage and weight loss, moisture content, susceptibility index, median development period, germination, and vigor test at the end of storage were collected. Eighteen out of a population of twenty-four cowpea seed growers in Ghana were interviewed about cowpea seeds marketing strategy in Ghana; Greater Accra region (1), Northern region (8), Upper West region (7) and Volta region (4). The laboratory results showed that four varieties (Sangaraka, AGRAC-216, Simba, and Djiguiya) were resistant to C. maculatus, and twenty-nine were moderately resistant. However, the percentage of seed damage, seed weight loss, and moisture content were positively related with the susceptibility index. Susceptible index (SI) was positively significantly correlated with the percentage of seed damage (r=0.208, P<0.05). The percentage of germination (r=-0.313, P<0.01), reproductive efficiency (r=-0.723, p<0.01), percentage of seed vigor (r=-0.104, P<0.01) and adult mortality (r=-0.391, P<0.01) were high significantly and negative correlated with SI. The best marketing strategy included: Protecting seeds in store to supply quality seed; depending on government, own and market price, selling directly to farmers and retailers and promotion through personal selling to farmer groups or the cost of production. Therefore, the use of insect-resistant varieties would offer food security and minimize post-harvest losses of seed storage, especially for seed growers, retailers, and farmers who keep the seeds after harvesting for future use.