Genetic diversity in common bean accessions evaluated by means of morpho-agronomical and RAPD data

Abstract

Germplasm banks store genotype samples, improved varieties, landraces and wild species, all generically denominated accessions. The importance of characterizing germplasm banks is based on the identification and knowledge of relevant traits for genetic improvement and ex situ germplasm conservation. Thus, the present study had as aim the evaluation of the genetic diversity among 220 accessions of a Brazilian common bean germplasm bank of the "Instituto Agronômico de Campinas" (IAC) by means of 23 morpho-agronomical descriptors and 19 RAPD loci. These accessions correspond to genotypes from the Andean and Middle American gene pool as well as from cultivars derived from common bean improvement programs. The Middle American accessions and the improved cultivars were clustered into one group, distinct from the one formed by the Andean accessions. In relation to the molecular data, 47% of the genetic similarity was detected among the Middle American accessions, and similar results were observed for the improved cultivars (50%). The Andean accessions revealed 60% of genetic similarity. The cluster constituted by the improved cultivars and the Middle American genotypes differed, basically, in tegument color. Both molecular and morpho-agronomical data sets were equally effective to quantify and organize the genetic diversity of common bean accessions. This information may be useful to direct crosses and for the proper organization of the IAC germplasm bank.

Genetic diversity in speckled bean (Phaseolus vulgaris L.) genotypes in Ethiopia

“…In agreement with this investigation, Vasic et al (2008) evaluated common bean population and reported that six PCs explained 80% of the total variability. However, other investigators observed low variation in the first two components in common bean (Machado et al, 2002;Rodrigues et al, 2002;Chiorato et al, 2007;Lima et al, 2012) using 12,51, 220, and 100 genotypes, respectively.…”

Genetic divergence of roundup ready (RR) soybean cultivars estimated by phenotypic characteristics and molecular markers

“…However, Li et al (2008) found moderate correlation coefficients (r=0.31 p < 0.01) in soybean utilizing SSR markers. Chiorato et al (2007), on correlating matrices from agronomic variables and RAPD molecular descriptors in dry beans, also found moderate correlation coefficients (r=0.33, p<0.01). The difference between the most divergent cultivar pairs found from the Euclidean distance and Jaccard's Coefficient, as well as the low correlation between the phenotypic and molecular data, indicate that each method estimated the divergence between genotypes in a distinct way.…”

“…Multivariate analysis based on phenotypic data has been used to access genetic diversity of soybean (Mikel et al, 2010;Salimi et al, 2012;Peluzio et al, 2012); has also occurred with many of plants species, such as bean (Chiorato et al, 2007), cotton (Li et al, 2008) and rubber tree (Gouvêa et al, 2010).…”

“…The experimental area was homogeneous and each block consisted of a single 5 m row, with 0.5 m spacing between rows. This design was adopted owing to the small number of available seeds and according to the methodology used by germplasm banks, where the genotypes are planted in single rows, without repetitions (Carvalho et al, 2003;Chiorato et al, 2007). The agronomic traits were evaluated using the mean data of six plants collected at random within the block.…”

Characterization of genetic variability among common bean genotypes by morphological descriptors

“…The morpho-agronomic description provides information underlying conclusions on the genetic variability of the genotypes of the bank, identification of accessions maintained in duplicate (Valls 2007), improvement of the data of identification and classification of accessions (Chiorato et al 2007) and support the regeneration and maintenance of the genetic integrity of genotypes. Among other information that can be obtained from the characterization of germplasm, the determination of the relative importance of the traits used to describe the genetic diversity (Rodrigues et al 2002, Chiorato et al 2005) is noteworthy because, in case of limited financial and/or human resources, the least relevant traits can be eliminated.…”