Mapeamento de QTLs para reação ao oídio e mancha-angular do feijoeiro-comum em diferentes locais

Abstract

Resumo -Os objetivos deste trabalho foram mapear, em diferentes locais, marcadores RAPD ligados a QTLs (Quantitative Trait Loci) de reação do feijoeiro-comum ao oídio e à mancha-angular, avaliar a interação de QTLs por locais e comparar os métodos de mapeamento e regressão múltipla no processo de detecção de QTLs. Foram avaliadas 196 linhagens recombinantes, oriundas do cruzamento entre as cultivares Carioca e Flor de Mayo, em duas épocas de cultivo: época da seca, para mancha-angular, e inverno para oídio, nos anos de 1996, 1997 e 1998, em dois locais de Minas Gerais. Foram conduzidos sete experimentos de avaliação fenotípica utilizando o delineamento experimental em látice quadrado simples. Os resultados mostraram que a interação QTLs por locais foi significativa, mas foram identificados alguns QTLs com maior estabilidade. O método da regressão múltipla detectou maior número de marcadores ligados a QTLs do que o processo de mapeamento por intervalo composto; não houve concordância entre os resultados apresentados pelos dois métodos. Os marcadores que se mostraram mais estáveis e promissores para serem utilizados em programas de seleção assistida foram OPR02-832, OPD08-759 e OPN10-851 para reação a oídio; OPN02-436, e OPN07-1072 para reação à mancha-angular.Termos para indexação: Phaseolus vulgaris, marcadores genéticos, DNA, variação genética, doenças das plantas. Mapping QTLs for reaction to powdered mildew and to angular leaf spot in common beans under different environmentsAbstract -The objectives of this work were to identify, under different environments, RAPD markers linked to QTLs (Quantitative Trait Loci) that control the reaction to powdered mildew and to angular leaf spot a segregating population of common beans, to evaluate the existence of interactions involving QTLs with planting dates and to compare detection procedure of markers linked to QTLs utilizing the methods of mapping and multiple regression. One hundred and ninety-six recombinant inbred lines derived from the cross of cultivars Carioca x Flor de Mayo under two traditional sowing dates were evaluated for common beans (drought for evaluating the angular leaf spot, and winter for evaluating the powdered mildew) in 1996, 1997 and 1998, in two localities of Minas Gerais State, Brazil. For the phenotypic evaluation of the families, seven field experiments were conducted. The experimental design used was a 14x14 partially balanced square simple lattice. Results indicated that interaction of QTLs by local were significant, and some QTLs with stability were identified. Multiple regression analysis identified a greater number of QTLs-linked markers than the process of composite interval mapping. There was no coincidence between results obtained with the two methods for the majority of the traits studied. Molecular markers which were considered of greater potential use on marker-assisted selection were OPR02-832, OPD08-759 and OPN10-851 for reaction to powdery mildew and OPN02-436, and OPN07-1072 for reaction to leaf blight.

QTL mapping for angular leaf spot in common bean using microsatellite markers

“…When considering the interaction treatments x environments and its partitionings, it is possible to verify influence on the reaction to angular leaf spot, similar contributions of the interaction treatments x locals and of treatments x years, and the absence of triple interaction. The partition of the interaction treatments x environments demonstrated once more the predominance of the complex part of the interaction, in this case 99.97%, which shows that the interaction treatments x environments was nearly completely due to its complex portion, in line with the results obtained by Melo et al (2002). Phenotypic correlations were however high, varying from 0.49 to 0.64, as well as the Spearman correlation which varied from 0.46 to 0.63.…”

“…The coefficients of variation varied from 12.68 to 21.22%, indicating a smiilar experimental precision to the one observed in field experiments (Rezende et al 1999, Melo et al 2002. The treatment effect was significant for reaction to angular leaf spot in all experiments.…”

“…Studies on the genetic control of reaction to angular leaf spot are not yet conclusive (Bett and Michaels 1995, Rezende et al 1999, Faleiro et al 2003. Melo et al (2002) observed heritability for reaction to angular leaf spot varying from 44.44 to 58.86% and suggested that in the case of low heritability marker-assisted selection is more advantageous; they verified the presence of interaction genotypes x environments of the complex type; through the process of linear regression they found ten QTL associated to the reaction to angular leaf spot and two QTL by the method of composite interval mapping. They therefore suggested the use of primers OPN-02 and OPN-07 in assisted selection for reaction to angular leaf spot.…”

Interação com ambientes e estabilidade de genótipos de feijoeiro-comum na Região Centro-Sul do Brasil

“…No entanto, todos os genótipos apresentaram ampla variação de reação às doenças nos ambientes testados. Assim, parte da interação genótipos com ambientes, obtida neste estudo, ocorreu em razão da diferença na incidência e severidade das doenças nos diversos ambientes, ocasionada por variações nas condições climáticas e nas populações de patótipos, assim como observado por Melo et al (2002) para oídio e mancha-angular.…”

Incorporation of resistance to angular leaf spot and bean common mosaic necrosis virus diseases into adapted common bean (Phaseolus vulgaris L.) genotype in Tanzania

“…Some other studies revealed that the heritability for reaction to angular leaf spot was varied from 44.44 to 58.86% and it was suggested that in the case of low heritability, marker assisted selection is more advantageous (Melo et al, 2002cited by Teixeira et al, 2005. It has also been reported that there is a complex interaction between genotype and environment which also gives the basis in deciding on the adoption of indirect selection based on molecular markers (Teixeira et al, 2005).…”