Efeito da seleÃÃo natural em alelos microssatÃlites (SSR) do feijoeiro e associaÃÃo com QTLs de caracteres agronÃmicos / Effect of natural selection on common bean SSR alleles and their association with agronomical QTLs.

AUTOR(ES)
DATA DE PUBLICAÇÃO

2004

RESUMO

The objectives of this study were to identify microsatellite (SSR) markers selected by natural selection, and their association with QTLs for grain yield, angular leaf spot reaction and 100 seed weight, in common bean (Phaseolus vulgaris) segreganting populations. One hundred and seven families from the F8 generation and 107 from the F24, derived from the Carioca MG x ESAL 686 cross, were conducted by bulk method. The families were evaluated for grain yield in the fall/winter season of 2001 (F8:9 and F24:25), spring/summer of 2001/2002 (F8:10 and F24:26), and summer/fall of 2002 (F8:11 and F24:27) in Lavras, MG State. Plant reaction to angular leaf spot (Phaeoisariopsis griseola) and 100 seed weight were evaluated only in the last season. DNA extraction was set up from F8:11 and F24:27 families, and used in the SSR reaction with 30 pair of primers that identified polymorphism in the parents and in a DNA bulk of the F24:27 families. In twenty nine out of 30 loci the allele from Carioca MG were selected by natural selection, and in only one locus was selected the allele from ESAL 686. The natural selection affected all generations, and its intensity was specific for each locus and generation. Therefore, the selected alleles of all loci should be important for improving adaptation. Using the multiple linear regression through the stepwise procedure, 10 grain yield QTLs were identified by the SSR markers which explained each one between 3.1% a 9.4% of the phenotypic variation. For angular leaf spot 6 QTLs were identified and the one with the largest effect (BM154) explained 17.5% of the phenotypic variation. Five QTLs were also identified for 100 seed weight, and the primer X61293 presented the largest effect and explained 16.8%. Most QTLs expressed in only one environment and population, showing their high instability, which might be due to the genotipic frequencies, both of the markers and the agronomical traits.

ASSUNTO(S)

seleÃÃo melhoramento genÃtico vegetal. feijÃo caracterÃstica agronÃmica phaseolus vulgaris plant breeding. melhoramento vegetal phaseolus vulgaris common bean selection

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