Genetic diversity in cultivated carioca common beans based on molecular marker analysis

Abstract

A wide array of molecular markers has been used to investigate the genetic diversity among common bean species. However, the best combination of markers for studying such diversity among common bean cultivars has yet to be determined. Few reports have examined the genetic diversity of the carioca bean, commercially one of the most important common beans in Brazil. In this study, we examined the usefulness of two molecular marker systems (simple sequence repeats – SSRs and amplified fragment length polymorphisms – AFLPs) for assessing the genetic diversity of carioca beans. The amount of information provided by Roger’s modified genetic distance was used to analyze SSR data and Jaccards similarity coefficient was used for AFLP data. Seventy SSRs were polymorphic and 20 AFLP primer combinations produced 635 polymorphic bands. Molecular analysis showed that carioca genotypes were quite diverse. AFLPs revealed greater genetic differentiation and variation within the carioca genotypes (Gst = 98% and Fst = 0.83, respectively) than SSRs and provided better resolution for clustering the carioca genotypes. SSRs and AFLPs were both suitable for assessing the genetic diversity of Brazilian carioca genotypes since the number of markers used in each system provided a low coefficient of variation. However, fingerprint profiles were generated faster with AFLPs, making them a better choice for assessing genetic diversity in the carioca germplasm.

Genetic Control of Seed Coat Darkening in Common Bean Cultivars from Three Market Classes

“…The mean number of alleles per marker was 3.75. These estimates were lower than those obtained by Díaz et al (2011) and Perseguini et al (2011), who also analyzed the diversity of common bean lines based on microsatellite loci. However, these authors evaluated lines from germplasm banks, for which greater genetic variability was expected compared with analysis of lines collected from a study of a breeding program in which the genetic base is more restricted and selected for market requirements.…”

“…The estimation of genetic similarity among common bean elite lines using molecular markers allow us to make inferences regarding genetic variability among them (Díaz et al, 2011; Perseguini et al, 2011). Molecular markers have made valuable contributions in this respect, especially in detection of genetic relatedness among different genotypes in studies of genetic diversity and gene mapping.…”

Common bean genotypes for agronomic and market-related traits in VCU trials

“…Thus, the inability to obtain genotypes superior to the controls for grain yield could be explained by pointing to restrictions in the genetic base of the breeding programs in Brazil. But, in practice, this does not occur, as identified by Perseguini et al (2011), who analyzed the genetic base of 60 genotypes of carioca seed coat, including the main cultivars developed in Brazil, and proved that the genetic base of the common bean breeding programs in Brazil is not narrow.…”

Demarcation of informative chromosomes in tropical sweet corn inbred lines using microsatellite DNA markers

“…This could be due to their capacity to detect codominantly inherited length polymorphisms of repetitive DNA sequences, and thus discriminate between large numbers of alleles (Matsuoka et al , 2002; Perseguini et al , 2011). Variation among the 10 sweet-corn chromosomes, obtained from the inbred lines investigated here, could be a expeditious basis for determining the degree of genetic relationships among different lines, or for detecting genes linked to microsatellite loci.…”