Microssatellite marker assisted selection for grain yield in common bean. / SeleÃÃo assistida por marcadores microssatÃlites para produtividade de grÃos em feijoeiro

AUTOR(ES)

Helton Santos Pereira

DATA DE PUBLICAÇÃO

2006

RESUMO

The selection of promising populations and segregant families for grain yield is very important to the success in a common bean breeding program. The objectives of the research were to select superior segregating populations for grain yield using phenotypic and grain yield QTL markers, to select grain yield promising families derived from selected populations, and to verify the efficiency of marker assisted selection (MAS) in relation to phenotypic selection. Fourty nine lines were evaluated in two field trials in the dry season of 2004, one in Lavras, and the other in Lambari, using a triple 7x7 lattice design with plots of two 3m rows. Grain yield, angular leaf spot reaction and the plant architecture were evaluated. Seven lines were selected and intercrossed according to the diallel scheme and also genotyped with 24 SSR markers of QTLs related to grain yield previously identified. The F2 populations were evaluated in a RCB design with three replications and plots of two 3m rows in Lavras. 25% of the SSR markers used were polymorphic in the parents with a maximun of four in one population. Four segregating populations were selected based on the grain yield of the lines, on combining ability of the parents, and on the QTL markers polymorphism between the parent combinations. From those populations, 394 families were taken and evaluated for grain yield in the F3:4 in the rainly season of 2005/2006 in a simple lattice design with plots of one 1m row. The F3:5 families were evaluated in the dry season of 2006, using a triple lattice design with plots of one 2m row. The families from three populations were genotyped with the previously identified polimorphic QTL markers. The best families (10%) were selected based on grain yield and on an index using phenotypic and markers information (MAS). The markers explained a small part of phenotypic variation and showed QTLs by environments and QTLs by populations interaction. The phenotypic selection achived higher gains in all populations and the MAS also achived gains, although, in lower intensity. 40% of the families were selected in both selection methods. The selection of superior families was achived by both methods, although the phenotypic selection was more efficient, mainly due to the small number and effects of the available markers. So, in this condictions the molecular informations presented low contribution.

ASSUNTO(S)

seleÃÃo de famÃlias microsatellite produÃÃo de grÃos molecular markers phaseolus vulgaris marker assisted selection melhoramento vegetal melhoramento de plantas phaseolus vulgaris populaÃÃes segregantes microssatÃlites plant breeding common bean segregant populations feijÃo seleÃÃo assistida por marcadores marcadores moleculares

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