Application of <i>Cry1Ab/Ac Bt</i> strip for screening of resistance for <i>Maruca vitrata</i> in cowpea

Abstract

Maruca vitrata is a significant constraint to cowpea production in most cowpea growing areas of sub-Saharan Africa. Yield losses caused by M. vitrata in these regions are estimated in millions of tons annually and the prevalence of M. vitrata infestation is steadily increasing. Recombinant DNA technology have led to development of some cowpea lines with Maruca resistance as well as other important agronomic traits but it is time-consuming and difficult to screen for the resistant trait especially in the segregating populations using conventional screening techniques, which will lead to delay in the development of Maruca resistant cowpea varieties. The use of allele-based selection tool will make it easier to select plant traits and reduce the time needed to develop new Maruca resistant cowpea varieties. In this study, the efficacy of using Cry1Ab/Ac Bt strip for detecting Maruca resistant transgene in transgenic cowpea was systematically investigated for the first time through field derived progenies. The results show that the Cry1Ab/Ac Bt strip was effective for detecting the presence of the resistant gene in cowpea genome. Maruca resistant plants were successfully screened from the segregating cowpea plants and the genetics of the gene was monitored. The Cry1Ab/Ac Bt strip was found to be suitable for genetic analysis of the Maruca resistant transgene in cowpea. This study has demonstrated the precision of using Cry1Ab/Ac Bt strips as a screening tool of transgenic lines containing Cry1Ab gene, this has an importance in the hybridization programme where genotypes having cry gene can be distinguished at seedling stage at lesser time, with the potential of putting the breeding process on a fast track and increase the efficiency of breeding activities.

Keywords: Bacillus thuriengiensis, Cry1Ab/Ac Bt strips, transgenic cowpea, Maruca vitrata.

African Journal of Biotechnology Vol. 12(40), pp. 5869-5874