Classification of physiological races of Fusarium oxysporum f. sp. phaseoli in common bean

• Autor(a) principal: Henrique,Francisco Humberto
• Data de Publicação: 2015
• Outros Autores: Carbonell,Sérgio Augusto Morais, Ito,Margarida Fumiko, Gonçalves,João Guilherme Ribeiro, Sasseron,Graziéle Ramos, Chiorato,Alisson Fernando
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Bragantia
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0006-87052015000100084
• topic: Fusarium wilt; Phaseolus vulgaris L.; cultivars differential races; soil

Fusarium wilt, caused by Fusarium oxysporum Schlecht. f. phaseoli Kendrick and Snyder (FOP), is a major disease of common bean, causing large economic losses. Genetic resistance is one of the main mechanisms of pathogen control, and knowledge of the physiological variability is fundamental in breeding for resistant cultivars. Thus, a method of pathogen classification that describes the variability and is useful in plant breeding of isolates from different sources was evaluated by different methodologies. Common bean plants of different sets of differentiating cultivars were inoculated with 25 FOP isolates and 3 controls, totaling 28 isolates evaluated 30 days after inoculation. The variability in the isolates found in this study differs from the results of other authors, who reported a small number of physiological races of the pathogen and disagrees with their evaluation of the races and the evaluation methodology. The proposed approach for binary classification based on a group of 12 differentiating cultivars demonstrated that the variability in pathogenicity of FOP is greater than reported so far. By this methodology, 27 different physiological races of the pathogen were obtained. The methods led to contrasting results, with double race classification in the same isolate. The physiological variability found indicates that the physiological races of the pathogen are not limited to 7 as previously mentioned.