Assessment of mutation induced bruchid (Callosobruchus spp.) resistance in cowpea

Abstract

A study was carried out at the Joseph Sarwuan Tarka University, Makurdi located at latitude 7.41⁰ N and longitude 8.39⁰ E. The laboratory experiment was carried out in the Plant Breeding and Seed Science laboratory of the University. The objective of the study was to assess the cowpea induced mutants for bruchid resistance. This is to mitigate the post-harvest losses experienced by farmers to bruchids. Genotypes used in the study were Fuampea 1, IFE BROWN and Sampea 14. The seeds were subjected to mutagenic treatment using experimental grade Ethyl Methane Sulphonate (EMS), Sodium Azide (SA), Hydroxylamine Hydrochloride (HH) at 0.01%, 0.05% and 0.1. The seeds obtained from this mutagenesis experiment in the fourth mutant generation were used to test for bruchid resistance. Bruchids were cultured and subsequent treatment of the mutant cowpea genotypes were carried out and data recorded. Results from Analysis of Variance showed that there was significant (P<0.01) genotype effect only for holes in seeds and mean development period. Mutagen effect was significant (P<0.01 and P<0.05) for only holes in seeds and number of eggs. Dose effect was also significant (P<0.01 and P<0.05) for holes in seeds. Genotype x Mutagen x Dose had significant (P<0.01 and P<0.05) variation in all the measured traits except for percentage bruchid emergence, percentage pest tolerance and growth index. From the present study it can be concluded that; EMS induced the only above susceptible resistance on the Dobie’s Index among the genotypes studied. EMS could potentially be used to induce bruchid resistance in cowpea.