ComprovaÃÃo da variabilidade patogÃnica dentro da raÃa 65 de Colletotrichum lindemuthianum / Proof of pathogenic variability within race 65 of Colletotrichum lindemuthianum

AUTOR(ES)
DATA DE PUBLICAÇÃO

2006

RESUMO

The wide pathogenic variation and the difficulty to distinguish possible differences among C. lindemuthianum isolates have resulted in problems to producers and commun breeders of beans. The aim of this work was to study the variation within the race 65 through the aggressiveness among different isolates and evaluate the genetic resistance (vertical and horizontal resistance) of P. vulgaris to C. lindemuthianum. Six isolates collected from different counties, host cultivars and years were used. The inoculations took place in the set of twelve differential cultivars and in seven commercial cultivars, according to the rules established by CIAT (1990). Besides the regular concentration of 106 spores/mL, the concentrations of 102, 103, 104 and 105 spores/mL have also been evaluated. Statistical analyses were carried out using the diallel method proposed by Melo &Santos (1999), which allowed getting information concerning the vertical and horizontal resistance of hosts as well as the aggressiveness of the pathogen. It was not possible to detect horizontal resistance in the C. lindemuthianum - common bean system, due to resistance alleles which increase the estimates of the general ability of reaction. Differences in the aggressiveness of isolates from race 65 were observed, being the CL 837 and CL 844 isolates, the most aggressive. Thus it is obvious that the set of differential cultivars to determine the C. lindemuthianum races was inefficient to detect differences within races 65, which suggests that new cultivars should be added.

ASSUNTO(S)

colletotrichum lindemuthianum cultivares diferenciadoras differential cultivars ciÃncias agrÃrias variabilidade patogÃnica colletotrichum lindemuthianum pathogenic variation

ACESSO AO ARTIGO

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