Toward a Comprehensive Resistance Management Plan for Bt Transformed Cowpeas to Control Maruca vitrata in West Africa
Auburn University (US); INRAN (Niger); INERA (Burkina Faso); IITA (Benin)
Larry Murdock (US); Mohammad Ishiyaku (Nigeria)
A potential problem facing Bt cowpeas is that cowpeas evolved and were domesticated as a crop in central Africa. Wild relatives of cultivated cowpeas persist in some areas adjacent to cowpea fields. Thus, research is needed to better understand and prevent pollen (and gene) flow from cultivated to wild plants. Two potential ways to do this involve (a) developing an obligate cleistogamous cowpea and (b) developing cowpea lines that are asynchronous in flower opening with wild cowpeas. Other mechanisms that reduce the incidence of outcrossing that might be useful in the prevention of gene flow include the manipulation of the duration and timing of anthesis in such a way as to ensure inter-varietal isolation. Research work undertaken by this component is intended to lead to the eventual production of – or recognition of existing -obligate cowpea lines with the possible addition of a late and short flower-opening traits. This trait could be introgressed into Bt cowpea lines in the future as a mechanism to limit gene flow from cultivated to wild cowpeas.
1. Determine distribution, abundance and migrations of Maruca vitrata adults. 2. Characterize Maruca populations with regards to susceptibility to specific Bt proteins (cry1Ab, cry2Ab and cry2Aa). Samples from the same populations tested will be subjected to microsatellite analysis. 3. Define micro-satellite markers for Maruca and use these markers to characterize Maruca populations over a two-year period over multiple collection sites located in the Nigerian grain-shed. 4. Develop obligate cleistogamous cowpea genotypes.