Molecular characterization of high performance inbred lines of Brazilian common beans

Abstract

ABSTRACT. The identification of germplasm genetic variability in breeding programs of the common bean (Phaseolus vulgaris) is essential for determining the potential of each combination of parent plants to obtain superior genotypes. The present study aimed to estimate the extent of genetic diversity in 172 lines and cultivars of the common bean by integrating five tests of value for cultivation and use (VCU) that were conducted over the last eight years by the breeding program of Embrapa Arroz e Feijão in Brazil. Nine multilocus genotyping systems composed of 36 fluorescent microsatellite markers distributed across 11 different chromosomes of the common bean were used, of which 24 were polymorphic. One hundred and eighty-seven alleles were identified, with an average of 7.79 alleles per locus and an average gene diversity of 0.65. The combined probability of identity for all loci was 1.32 x 10 between the selection cycles were identified, allowing the breeding program to develop a crossbreed between elite genotypes with a low degree of genetic relatedness. H E values (ranging from 0.31 to 0.63) and the genetic differentiation among the VCU tests (F ST of 0.159) supports for new strategies to increase the genetic base from which the program is conducted. Private alleles (26%) were identified and can be directly incorporated into the gene pool of cultivated germplasm, thereby contributing effectively to the expansion of genetic diversity in this bean-breeding program.

Genetic divergence of common bean cultivars

“…There was variation of 2-4 alleles per locus, with the primers PvBR25 and ATA6 being the most informative (Table 4). Cardoso et al (2013Cardoso et al ( , 2014 found a mean number of alleles per locus greater than that seen in the present study. In 2013, the authors evaluated the genetic divergence of 172 common bean lines and cultivars making up five VCU trials conducted by the genetic breeding program of Embrapa Arroz e Feijão using 30 pairs of polymorphic primers.…”

Simultaneous selection in beans for stability and high agronomic performance

“…However, the grain yield of common bean has dominant effects (Lima and Ramalho, 2016), suggesting difficulties in selection. Breeding programs for Brazilian black and carioca common bean have led to a reduction in the genetic diversity of agronomic traits (Cardoso et al, 2013). These results suggest that genetic gain for grain yield may be reduced in the future.…”

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

“…Genotyping to estimate genetic diversity among the lines used 24 microsatellite markers grouped into four multiplex panels containing six fluorescent markers each (Cardoso et al, 2013; Morais et al, 2016). The products of DNA amplification were analyzed in the automatic sequencer ABI 3500 XL (Applied Biosystems) and genotyping was performed by the computational program GeneMapper version 4.1 AB (Applied Biosystems).…”