Genetic diversity in the Lima bean (Phaseolus lunatus L.) as revealed by chloroplast DNA (cpDNA) variations

Genetic diversity in the Lima bean (P. lunatus L.) was assessed by means of two chloroplast DNA probes. Based on data obtained from 152 accessions including wild forms and landraces, the two separate Mesoamerican and Andean groups were confirmed and a transition pool of genetic diversity was observed in the two botanical forms consistent with their distribution range. Three primary centres of genetic diversity and one secondary diversification spot are proposed for the wild Lima bean whereas only two domestication sites are underlined for the landraces. The importance of human intervention in widening the distribution range and the genetic diversity in landraces is discussed.