Effect of natural selection on common bean (Phaseolus vulgaris) microsatellite alleles

Abstract

The effect of natural selection on microsatellite simple sequence repeat (SSR) alleles was investigated in two distinct common bean (Phaseolus vulgaris) generations (F 8 and F 24 ) derived from the cross between the P. vulgaris cultivars Carioca MG x ESAL 686. The F 2 segregant population was propagated by the bulk method and 107 plants were sampled in two generations (F 8 and F 24 ). Each plant generated one family which was replicated by the bulk method to F 8:11 and F 24:27 families from which DNA was extracted. Thirty pairs of microsatellite primers were polymorphic for the parents and the bulk of the F 24:27 families. Out of 30 loci selected by natural selection, 29 microsatellite alleles came from the Carioca MG parent and one allele came from the ESAL 686 parent. Natural selection affected all the generations and its intensity was specific for each locus and generation. Therefore all the alleles selected at each locus must be important for adaptation in a breeding program.

Genetic divergence of common bean cultivars

“…Nevertheless, this did not occur, probably due to the occurrence of a varietal mixture or cross pollination in the experimental stations of the institutions supplying the cultivars. It is necessary to consider, however, that in various SSR loci in common bean, there is heterozygosis even after 24 generations of self-pollination (Rodrigues and dos Santos, 2006).…”

“…Additionally, the kinship observed may also be due, in part, to the cultivars having loci in heterozygosis (H O ) in an amount greater than expected for autogamous plants, at least partially reflecting the occurrence of a mixture and the heterozygosis maintained through natural selection in autogamous plants like common bean (Rodrigues and dos Santos, 2006) (Table 4). This may also be observed in the dendrogram (Figure 2).…”

Identification of QTLs of resistance to white mold in common bean from multiple markers by using Bayesian analysis

“…DNA was extracted from the parents, CNFC 9506 and RP-2, and from the 186 F 2 progenies according to the procedures described by Rodrigues and Santos (2006). Nucleic acids were rehydrated in TE buffer and quantified by 1% agarose gel electrophoresis using DNA markers of known concentrations.…”

Development and application of microsatellites in plant breeding

“…Microsatellites have been used for plant genetic analysis such as to measure the effects of natural selection (Rodrigues and Santos 2006), to unveil the genetic diversity (Vieira et al 2009, Guan et al 2010, to measure population structure (Ribeiro et al 2010, Albertini et al 2011, to integrate the genetic, physical and sequence-based physical maps (McClean et al 2010) and for marker assisted selection (Benchimol et al 2005, Chen et al 2011). …”