Microsatellite markers reveal promising genetic diversity and seed trait associations in common bean landraces (Phaseolus vulgarisL.) from Nicaragua

Abstract

Nicaragua is located in the Mesoamerican diversity centre for common beans (Phaseolus vulgarisL.). Yet, there is insufficient knowledge of the molecular characteristics of most common bean landraces in Nicaragua. The objectives of the present study were to investigate the genetic diversity of common bean landraces and to identify promising sources of genetic variation for breeding purposes. Two cultivars and 40 landraces never studied before were selected from a collection based on the geographic origin, seed coloration and information provided by farmers. Fourteen microsatellite markers distributed in different linkage groups were analysed. The study revealed that there is a high genetic diversity (mean 8.9 alleles per locus). The populations showed structuring into three groups where seed weight had a strong relationship with population clustering. At least 20% of the populations hold promising allelic variation and potential for good market acceptance that could be maximized in breeding programmes. Additionally, four markers revealed a high correlation with seed length, width and weight, suggesting that marker-assisted selection for these yield-determinant traits could be straightforward. Nonetheless, more marker–trait associations should be addressed in order to enforce this practice.