Journal Article

Structure and Genetic Diversity of Wild Populations of Lima Bean (Phaseolus lunatus L.) from the Yucatan Peninsula, Mexico

Colunga-García Marín, P, Gepts, P, Delgado-Valerio, P, Martínez-Castillo, J, Zizumbo-Villarreal, D

2006

Overview

This study was conducted to determine the genetic diversity, structure and gene flow of 11 wild populations of Phaseolus lunatus L. in four regions of traditional agriculture in the Yucatan Peninsula, Mexico, part of the putative domestication area of its Mesoamerican gene pool. Analyzing eight microsatellite loci, the populations showed high values of diversity: observed heterozygosity (Ho) 0.46 to 0.9; Nei's index of diversity (H) 0.35 to 0.59 and average number of alleles per locus (A) 2.37 to 3.38. Both Nei's index of populations differentiation (Gst) and analysis of molecular variance (AMOVA) indicated strong differentiation. The Bayesian analysis of grouping and the Mantel test suggested isolation among agricultural regions as a major factor for population differentiation. Even though a low long-term gene flow (Nm = 0.66) and low rates of recent migration among populations were observed, there were some cases where the accidental transport of seeds could be favoring a gene flow at a long distance. Data found in this study suggest a positive correlation between agricultural intensification and increase in diversity, suggesting that wild populations are favored by the intensification of disturbance in situations involving at least 3 yr of fallow. However, the opposite could be true at higher levels of intensification as has been reported in the Central Valley of Costa Rica, where the diversity is diminishing.

• Publisher: Crop Science Society of America,American Society of Agronomy
• Subject: Agronomy. Soil science and plant productions / Beans / Biological and medical sciences / Domestication / fallow / Flowers & plants / Fundamental and applied biological sciences. Psychology / Gene flow / Generalities. Genetics. Plant material / Genetic aspects / genetic distance / Genetic diversity / genetic markers / Genetic resources, diversity / genetic variation / Genetics and breeding of economic plants / heterozygosity / Intensive farming / Lima bean / lima beans / Mexico / microsatellite repeats / molecular sequence data / Phaseolus lunatus / plant communities / Plant material / Population differentiation / population genetics / population structure / Seeds / Traditional farming / wild plants / wild relatives