Melhoramento de feijões preto e vermelho visando a resistência à antracnose, ferrugem e mancha-angular, como o auxílio de marcadores moleculares

• Autor(a) principal: Costa, Márcia Regina
• Data de Publicação: 2007
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/1426
• topic: Feijão; Resistência; Piramidação; Marcadores genéticos; Beans; Resistance; Pyramid; Molecular markers; CNPQ::CIENCIAS BIOLOGICAS::GENETICA::GENETICA MOLECULAR E DE MICROORGANISMOS

Anthracnose, rust, and angular leaf spot incited by Colletotrichum lindemuthianum, Uromyces appendiculatus and Pseudocercospora griseola, respectively, are important diseases causing serious damages to the common bean crop. The common bean breeding program of BIOAGRO/UFV developed a line with carioca type grains (Rudá "R") containing the following resistance genes: Co-4, Co-6 and Co-10 (anthracnose); Ur-ON (rust) and Phg-1 (angular leaf spot). To transfer those genes to a black bean background, a backcrossing program was conducted with the aid of molecular markers, by involving Rudá "R" (donor genitor) and cultivar Diamante Negro (recurrent genitor). By selfing 32 BC3F1 plants, 40 black grained lines were obtained that possessed combinations with at least three markers linked to those genes. The lines were evaluated for resistance to the different races of C. lindemuthianum, U. appendiculatus and P. griseola. Lines DNR14 and DNR16 were resistant to all evaluated races of C. lindemuthianum, except for race 2047. Lines DNR12, DNR31, DNR36 and DNR38 were resistant to two races of U. appendiculatus. Lines DNR3, DNR4, DNR5, DNR7, DNR8, DNR10, DNR12, DNR24, DNR30, DNR33 and DNR34 were resistant to all races of P. griseola tested. The yield potentials of all 40 lines were evaluated during the winter season of 2006 and the dry season of 2007. The yield potentials of all lines were statistically equal to or higher than those of Rudá R and Diamante Negro. To increase the gene pyramid in the black-type background BC3F2 plants Diamante Negro x Rudá "R") containing the genes Co-6, Co-10, Ur-ON and Phg-1 were crossed with the carioca line Rudá "R1" carrying the genes Co-42, Co-5, Co-6, Co-10, Ur-ON and Phg-1. From this crossing and selection with molecular markers, 35 F4 families with black grains and at least five resistance markers were obtained. F2 plants [BC3F2 (Diamante Negro x Rudá "R") x Rudá "R1"] containing the genes Co-42, Co-5, Co-6, and Phg-1 were crossed with plants of the F2:3 families containing the genes Ur-ON, Ur-5 and Ur-11 for transfering the Ur genes to the black bean pyramid. It was possible to obtain eight F3 families with at least five markers associated to resistance genes; however, two of them showed carioca type grains, whereas the grains of the other ones did not present the grain patterns acceptable for either the groups carioca or black. Plants [BC3F2 (Diamante Negro x Rudá "R") x Rudá "R1"] containing the genes Co-42, Co-5, Co-6, Co-10, Ur-ON and Phg-1 were crossed with the cultivar MAR 2 (Phg-MAR 2) and those with the genes Co-42, Co-5, Co-6, Co-10 and Ur-ON were crossed with the cultivar Cornell 49-242 (Phg-3). BC3F2 plants (Diamante Negro x Rudá "R") containing the genes Co-4, Co-6, Co-10, Ur-ON and Phg-1 were crossed with BC3F2 individuals (Rudá x BAT 332) harboring the Phg-62 gene. In the three crossings and at each generation, the plants obtained were selected with molecular markers linked to each gene involved into crossings and also with markers for the genes I and bc-3 which confer resistance to the Bean Common Mosaic Virus. From the first cross, 16 plants with at least eight genes were obtained, and nine out of the 16 plants generated black-colored seeds. From the second cross, 13 plants with eight or nine genes generating only black F3 seeds were obtained, but they were all shiny. From the third cross, ten F4 families with black grains and at least two resistance genes were obtained. To transfer resistance genes to red-grained beans, crossings and backcrossing cycles were conducted between the cv. Vermelhinho (recurrent genitor) and Rudá "R", as well as between cv. Ouro Vermelho (recurrent genitor) and Rudá "R1". In those crossings, selection were also based on molecular markers linked to the genes of interest and on the grain color pattern. For the crossing between cv. Vermelhinho and Rudá "R", BC2F3 19 families containing at least two resistance genes and red grains were obtained. In the other crossing, 29 BC2F3 families with red grains and at least four markers were selected. According to the results, the following conclusions were drawn: the selection assisted by molecular markers in the process for obtaining lines with several resistance genes is efficient; the molecular markers should be tightly linked to the resistance genes; and transferring the genes between cultivars from different grain groups is slow, and requires a high number of backcrossings for recovering the original grain type.