Genetic Diversity of Bolivian Accessions of PhaseolusSpecies Evaluated with Fluorescent Microsatellite Markers

The Andes of South America is a center of origin for common beans (Phaseolus vulgarisL.) and lima beans (P. lunatusL.) that has been less well studied than other regions due to its high diversity and multitude of subenvironments. The objective of this study was to evaluate 174 accessions from five Phaseolusspecies native to Bolivia to determine their relationships and total genetic diversity using a set of 36 fluorescent microsatellite markers that are highly polymorphic and differentiate both between and within species. The results showed that the common beans were divided into a range of Andean groups and one disperse group of Mesoamerican accessions. The other species were well differentiated, including two scarlet runner beans (P. coccineusL.), 22 lima beans, and wild relatives P. augustiHarms and P. bolivianusPiper. Within the Andean groups, accessions with bicolor seeds were frequent and were typical of race Peru, subgroup I. These “vaquita” type beans were different from other subrace Peru genotypes without bicolor seeds and were also different from type I growth habit beans from race Nueva Granada. This latter race was unexpected for the region as it is from the northern Andes but occurred with some frequency in Bolivia. The diversity of Phaseolusbeans found in Bolivia is high with implications on germplasm conservation and the source of diversity in the Andean gene pool and in surrounding countries.