Laboratory Screening of Cowpea (Vigna unguiculata) Genotypes against Pulse Beetle, Callosobruchus maculatus (F.)
Siyunda AC, N Mwila, M Mwala, KL Munyinda and K Kamfwa
Published: February 05, 2022
Abstract
Research studies aimed at screening cowpea genotypes against Callosobruchus maculatus commonly known as a bruchid, under the no-choice infestation condition, were conducted at the Department of Plant Science, University of Zambia in Lusaka, Zambia during 2021 on 110 cowpea genotypes. The cowpea genotypes evaluated included 3 parental lines, 97 mutant lines, and 10 pure lines in order to discern the tolerant cowpea genotype against Callosobruchus maculatus that would aid the reduction of storage losses encountered in cowpea production. Parameters measured included., number of eggs laid per 100 seeds, adult emergence per cent, developmental period, growth index, per cent infestation, weight loss per cent, and frass produced. Significant differences were observed among the genotypes for all the parameters considered in the investigation. The most tolerant genotype BBBT1-11 across all parameters investigated, recorded 13.01 no. of eggs/100 seed compared to MS1-8-2-6-9-1 with 128.67 eggs/100 seeds. The adult emergence of BBBT1-11 was at 12.72% compared to the highest LTBT1-5 at 88.11%. BBBT1-11 also recorded the lowest growth index of 0.42 and frass produced of 0.23g compared to the highest growth index record of 4.19 in BB10-4-2-3-3 and the highest frass produced of 5.41g recorded in MS1-8-2-6-9-1. BBBT1-11 could be further assessed for the possible presence of bio chemical and genetic parameters, that could explain the basis of the observed differences among the genotypes in their reaction to Callosobruchus maculatus. Besides, BBBT1-11 can also be incorporated in the breeding program with the target of breeding cowpea varieties that are tolerant to bruchid infestation. Furthermore, BBBT1-11 may be released so as to address the storage losses experienced at postharvest in cowpea production.
Keywords: Callosobruchus maculatus; bruchid; tolerance