Plant & Animal Genome VI Conference Plant & Animal Genome VI Conference
P93
International Center for Tropical Agriculuture, CIAT, AA. 6713, Cali, Colombia
Genetic analysis using morphological and molecular markers (AFLP and microsatellites) has been used to understand the diversity between wild and cultivated Manihot species, with particular attention to the origin and domestication of cassava. Five wild species proposed as close relatives of cassava, one wild species expected to be more distant, and a representative sample from the cassava core collection maintained at CIAT were evaluated using 38 vegetative and reproductive descriptors, AFLP and microsatellite markers. Reproductive characters are essential to distinguish wild Manihot species. A group of 18 descriptors including vegetative and reproductive traits was recommended for taxonomic purposes and routine germplasm characterization. Results obtained with AFLP and microsatellite analysis showed individuals forming groups according to their prior taxonomic classification. M. aesculifolia, M. brachyloba and M. carthaginensis were the most distant species with respect to cassava; while M. esculenta subsp. flabellifolia and M. esculenta subsp. peruviana, which formed a mixed group, were the closest to the crop. This information supports the hypothesis that Brazil is the center of origin of cassava. It also shows that the cultivated germplasm presents a narrower range of variation than does the wild germplasm. Species-specific markers were found that may be useful for monitoring gene flow and introgression.