|Wilson, Jeffrey - Jeff|
Submitted to: Meeting Abstract
Publication Type: Proceedings
Publication Acceptance Date: 1/24/2004
Publication Date: 2/15/2004
Citation: Chee, P., Wilson, J.P. 2004. Genetic variability of wild pearl millets with striga resistance. Proceedings: Millet and sorghum-based systems in West Africa: Current knowledge and enhancing linkages to improve food security. McKnight Foundation Collaborative Crop Research Foundation. Niamey, Niger, January 27-30, 2004. http://mcknight.ccrp.cornell.edu/WEB-INF/documents/partic_docs/Niger04/WAf_Wilson_full(EN).pdf.
Interpretive Summary: Food insecurity is frequently associated with political instability. The inherently low food production in sub-Saharan Africa is the result of several different factors. Among these problems are weeds that are parasitic to crop plants. The parasitic weed striga frequently infects the staple grains corn, sorghum and millet. In West Africa, pearl millet is often grown in the harshest environments by some of the poorest peoples. Solving the striga problem will benefit some of the most needy populations in the world. Striga resistance was identified in several wild pearl millet accessions. Some of the more resistant lines were differentiated by molecular genetics techniques. The identification of potentially different sources of resistance will allow new resistant varieties of pearl millet to be bred, and will help to develop self sufficiency of food production in several West African countries.
Technical Abstract: Wild pearl millets have been selected from multi-location trials to be used as sources of resistance to Striga hermonthica for pearl millet improvement. Several wild accessions were confirmed to have a good level of resistance, however, the genetic relatedness among these accessions was unknown. In this study, we surveyed the genetic variability and the relationship among 80 wild pearl millet accessions collected from different regions in Africa that showed various levels of striga resistance, and a selection of cultivars and germplasm from Africa and the United States. We tested 30 PCR primer pairs targeting conserved gene sequences, of which 22 primer pairs produced reproducible and scorable DNA fragments. Most loci showed no amplicon length variation, but polymorphisms were revealed upon digestion of the PCR products with restriction enzymes. Preliminary analysis indicated that the genetic similarity among the accessions ranged from 0.66 to 1.00. Genotypic identity was not resolved in a number of accessions due possibly to the conserved nature of the gene sequences that we surveyed or perhaps that these genotypes are either identical or share a common parentage. For most accessions, the amount of variation that exists was sufficient for us to draw several conclusions regarding the relationships among these accessions. First, the tendency of improved cultivars and germplasm lines from the United States to cluster reflects their shared history in modern breeding. Second, the lack of clear clustering of African varieties and wild pearl millet accessions confirms that cultivation and improvement of pearl millet in Africa is not accompanied by genetic isolation. Finally, the observation that most of the known wild accessions with striga resistance fall into different clusters suggests that different sources of resistance may be available for use in breeding for striga resistant cultivars.