Interação diferencial entre Phaseolus vulgaris e Macrophomina phaseolina

• Autor(a) principal: Ferreira, Cristiane Silva
• Data de Publicação: 2019
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UFG
• Texto Completo: http://repositorio.bc.ufg.br/tede/handle/tede/9555
• topic: Rhizoctonia bataticola; Cultivares diferenciadoras; Especialização fisiológica; Doença do feijoeiro; Melhoramento de plantas; Rhizoctonia bataticola; Differential curtivars; Physiologic specialization; Bean disease; Plant breeding; AGRONOMIA::FITOSSANIDADE

Charcoal root rot caused by the soil-dwelling fungus Macrophomina phaseolina, anamorphic synonym Rhizoctonia bataticola, is more severe in regions with temperatures between 18 and 35 ° C and low humidity. Due to global warming it has become one of the most important diseases in the production of common bean in tropical countries. Its symptoms include dampping off, wilting, early defoliation and stem cancer, followed by death of plants under extreme conditions. The populations of this fungus present high pathogenic variability, which hinders its control. The present study had as objectives: 1) to investigate the variability of isolates of M. phaseolina fungus from State of Goiás; 2) to identify sources of horizontal and vertical resistance in bean genotypes; 3) to investigate the differential interaction between P. vulgaris and M. phaseolina to subsidize common bean breeding programs and provide information on the disease to farmers. Twenty - four isolates of M. phaseolina were analyzed by inoculation in a common bean cultivars set, proposed in previous study. Ten isolates were classified into four pathotypes, based on the cultivars susceptibility or resistance. M. phaseolina fungus race less aggressive II-1 was the most frequent. Races IB-47 and IB-64 were the less frequent. The cultivar BRS Embaixador was more susceptible to the fungus and allowed to identify three fungus race. BRS Pitanga and BRS Notável were the best candidates to be sources of durable and stable resistance. The results show how important is knowing M. phaseolina variability and its specific interaction with P. vulgaris, to establish new strategies in beans breeding programs and incorporation of resistance genes into new cultivars.