New sources of cowpea genotype resistance to cowpea bruchid Callosobruchus maculatus (F.) in Uganda

Abstract
Cowpea bruchid Callosobruchus maculatus (F.) is a major constraint to cowpea production throughout subsaharan Africa. The identification of sources of C. maculatus resistance and their incorporation into breeding programs would be a beneficial strategy to combat the devastation caused by the bruchid in stored cowpea. We evaluated 145 cowpea genotypes from Uganda and introductions from Kenya and Nigeria for resistance to bruchids. The mean number of eggs and number of holes, percentage pest tolerance, percentage weight loss, bruchid developmental period, bruchid growth and Dobie susceptibility index were significantly different among the 145 genotypes. Based on Dobie susceptibility index value, there were 18 resistant, 114 moderately resistant and 13 susceptible genotypes. Dobie’s susceptibility index correlated negatively with insect development period and percentage pest tolerance, and positively with number of eggs, growth index, number of holes and weight loss. The study identified new sources of cowpea from the studied genotypes that could be used by cowpea breeders to develop cultivars with relatively high resistance to cowpea bruchid. However, further investigations and identifcation of biochemicals that are responsible for cowpea seed resistance to bruchid are recommended.
Description
Keywords
Dobie susceptibility index, Exit holes, Growth index, Pest tolerance, Vigna unguiculata
Citation
Miesho, WB, Gebremedhin, HM, Msiska, UM, Mohammed, KE, Malinga, GM, Sadik, K., ... & Kyamanywa, S. (2018). New sources of cowpea genotype resistance to cowpea bruchid Callosobruchus maculatus (F.) in Uganda. International Journal of Agronomy and Agricultural Research , 12 (4), 39-52.