80 Crop Breeding and Applied Biotechnology 5:80-85, 2005 EC Palomino et al. Crop Breeding and Applied Biotechnology 5:80-85, 2005 Brazilian Society of Plant Breeding. Printed in Brazil Genetic diversity of common bean genotypes of Carioca commercial group using RAPD markers Edwin Camacho Palomino 1* , Edson Seizo Mori 1 , Léo Zimback 2 , Evandro Vagner Tambarussi 1 , and Cristiano Bueno de Moraes 1 Received 17 May 2004 Accepted 19 January 2005 ABSTRACT - The objective of this research was to characterize the genetic diversity of bean genotypes (Phaseolus vulgaris L.), from Carioca commercial group, utilizing RAPD markers to discriminate and to support breeders to choose genetic material and to develop breeding methods to use for obtaining new cultivars with Carioca type seeds. Twenty-eight genotypes, fifteen cultivars, and thirteen lines were evaluated. The genetic distances were achieved utilizing the Euclidian’s method modified by Roger’s (1972) and the grouping analysis were by UPGMA method, showed by a dendogram. Through 89 RAPD loci, obtained from 12 primers, 65.17% were polymorphics. We have verified that the RAPD markers were efficient in discrimination and grouping of genotypes, showing to have large genetic variability. Although Carioca cultivar has a common ancestor from all studied material, it has shown low similarity with genotypes derived from it, corroborating to exist sufficient genetic variability for production of new cultivars, maintaining the original coloration of seeds. Key words: Phaseolus vulgaris, molecular markers, RAPD, genetic distances. . INTRODUCTION The common bean (Phaseolus vulgaris L.) is one of food source with high level of protein for Brazilian diet, being Brazil the biggest world bean producer from genus Phaseolus, and the majority of grain yield are consumed in Brazil, specially from Carioca type bean. The grains are eatten for majority of Latin America and Africa populations being as one of the unique protein source from them (Center of Tropical Agriculture 1992). The total area in Brazil cultivated with commercial 1 Departamento de Produção Vegetal, Setor Agricultura, FCA/UNESP, C. P. 237, 18.603-970, Botucatu, SP , Brasil. *E-mail: edwin@fca.unesp.br 2 Floresta Estadual de Botucatu, Instituto Florestal group of Carioca bean has after thirty years since the begining from pure line approximately 2 million of hectars, (Almeida et al. 1971). Certainty, throughout the time, has occurred changing in the genetic structure of original Carioca cultivar, creating higher variability because of segregation passing by the continuous use from the same seeds yielded by the farmers, exposed from mutations, and mainly by production of new cultivars in breeding programs. However, those new cultivars maintained as pattern of Carioca grain type, still phenotypically similar for the most