Etude comparative de la diversité et de la structure génétique de populations sauvages de Phaseolus lunatus L. à l’aide des marqueurs enzymatiques et microsatellites

Comparative study of genetic diversity and structure of wild Phaseolus lunatus L. populations using enzymatic and microsatellite markers. Genetic diversity within and among Phaseolus lunatus L. var. silvester populations from the central valley of Costa Rica was studied using enzymes and microsatellite markers. As expected, microsatellite markers showed more genetic diversity than enzymes markers. However, the relatively moderate genetic diversity displayed can be explained by restricted origin of samples to the central valley of Costa Rica or by the source of the primer. Total genetic diversity (HT) and within population genetic diversity (HS) were underestimated with enzyme markers. The contribution of among population genetic diversity (DST) to total genetic diversity was similar for both markers. Enzymes and microsatellite markers pointed out a high inbreeding level for whole population (FIT) and within population (FIS). Within population genetic diversity represents 70% for both genetic markers. So, Lima bean wild populations at the central valley of Costa Rica may constitute valid in situ conservation unit. Wild populations natural sites are submitted to an accelerate change of land use because of demographic pressure and agriculture intensification. It is necessary to conduct an ex situ conservation associated with an in situ conservation. Seeds from the most threatened populations should be collected for an ex situ conservation.