MORPHOLOGICAL AND MOLECULAR VARIABILITY AMONG NATIVE AND COMERCIAL CULTIVARS OF BLACK BEAN IN TABASCO, MÉXICO

Abstract

Genetic variability among seven native black bean cultivars (Phaseolus vulgaris L.) collected in La Chontalpa, Tabasco, México, and 14 improved varieties were evaluated regarding morphological and molecular markers, such as RAPD and ISSR. The principal component analysis indicated that both types of varieties are highly related. Native genotypes are related to the improved ones. Among the native landraces, ‘Pondoy native bean’, ‘Black native bean 16 and 17’ and ‘Two months’ showed a close spatial link, related to the variables aerial biomass dry weight, growth seed rate, and pod wall proportion. The cluster analysis based on the genetic similarity data of RAPD-ISSR markers which was estimated with Dice Coefficient, showed low variability among genotypes, thus showing a close kinship among the black bean genotypes, which have a difference of only 6 %. It is inferred that native varieties have common ancestors with the improved varieties or lines used for black bean breeding programmes in México. These varieties have achieved some especial adaptation to the humid environmental conditions of Tabasco, due to the selection carried out by local farmers.