Genetic diversity analysis of common beans based on molecular markers

Homar R Gill-Langarica,José S Muruaga-Martínez,M.L Patricia Vargas-Vázquez,Netzahualcoyotl Mayek-Pérez,Rigoberto Rosales-Serna

doi:10.1590/s1415-47572011005000056

Abstract

A core collection of the common bean (Phaseolus vulgaris L.), representing genetic diversity in the entire Mexican holding, is kept at the INIFAP (Instituto Nacional de Investigaciones Forestales, Agricolas y Pecuarias, Mexico) Germplasm Bank. After evaluation, the genetic structure of this collection (200 accessions) was compared with that of landraces from the states of Oaxaca, Chiapas and Veracruz (10 genotypes from each), as well as a further 10 cultivars, by means of four amplified fragment length polymorphisms (AFLP) +3/+3 primer combinations and seven simple sequence repeats (SSR) loci, in order to define genetic diversity, variability and mutual relationships. Data underwent cluster (UPGMA) and molecular variance (AMOVA) analyses. AFLP analysis produced 530 bands (88.5% polymorphic) while SSR primers amplified 174 alleles, all polymorphic (8.2 alleles per locus). AFLP indicated that the highest genetic diversity was to be found in ten commercial-seed classes from two major groups of accessions from Central Mexico and Chiapas, which seems to be an important center of diversity in the south. A third group included genotypes from Nueva Granada, Mesoamerica, Jalisco and Durango races. Here, SSR analysis indicated a reduced number of shared haplotypes among accessions, whereas the highest genetic components of AMOVA variation were found within accessions. Genetic diversity observed in the common-bean core collection represents an important sample of the total Phaseolus genetic variability at the main Germplasm Bank of INIFAP. Molecular marker strategies could contribute to a better understanding of the genetic structure of the core collection as well as to its improvement and validation.

Highlights

Mexico is a major center in domestication and genetic diversity of the common bean (Phaseolus vulgaris L.) (Logozzo et al, 2006), which, together with maize (Zea mays L.), constitutes the most important source of proteins in the Mexican diet, and comprises the basic daily meal for most people, countrywide
Significant genetic differentiation (p < 0.01) among accessions within groups and accessions was detected with AMOVA, only when germplasm was classified by geographical origin (Tables 6 and 7)
High genetic diversity was detected in the INIFAP common-bean core collection, this diversity increasing, when the various geographical origins or seed types of the germplasm came under analysis

Summary

Introduction

Mexico is a major center in domestication and genetic diversity of the common bean (Phaseolus vulgaris L.) (Logozzo et al, 2006), which, together with maize (Zea mays L.), constitutes the most important source of proteins in the Mexican diet, and comprises the basic daily meal for most people, countrywide. In Mexico, wild, weedy populations have been primarily considered as genetic sources for germplasm and cultivar development (Chacón et al, 2005). Common-bean cultivars originally arose from the domestication of multiple wild, weedy landrace populations (Gepts et al, 1986; Gepts and Bliss, 1986; Gepts and Debouck, 1991; Chacón et al, 2007). Genetic diversity is being maintained at the INIFAP Germplasm Bank located near Texcoco

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Conclusion