Charcoal rot severity and yield components of common bean cultivars inoculated with Macrophomina phaseolina

English. ABSTRACT Macrophomina phaseolina is a soilborne pathogen with a wide range of hosts and its control through agricultural practices is difficult. The aim of this study was to quantify the severity of root rot (SRR) caused by M. phaseolina in common bean cultivars and its impact on yield components. The experiments were carried out under greenhouse conditions with the common bean cultivars ‘ANFC-9 Agro Norte’, ‘BRS Esteio’, ‘BRS Estilo’, ‘BRS Pérola’, ‘FTS Soberano’, ‘IPR Campos Gerais’, ‘IPR Tangará’, ‘IPR Tuiuiú’, ‘IPR Uirapurú’ and ‘TAA Dama’. Three isolates of M. phaseolina obtained from infected plants of common bean, soybeans and maize were inoculated in the common bean cultivars. In the phenological stage R9 of grain harvest maturity, the SRR and the yield components of root dry mass (RDM), number of pods per plant (NPP), number of grains per plant (NGP) and grain mass per plant (GMP) were assessed. All common bean cultivars were susceptible to M. phaseolina, showing a reduction in NPP, NGP and GMP. SPR was greater than 75%, regardless of the origin of isolates. Considering the average of cultivars, there was a significant decrease of 54.3% in RDM, compared to control treatments. The cultivars ‘IPR Tangará’, ‘ANFC-9 Agro Norte’, ‘BRS Esteio’, ‘BRS Pérola’ and ‘FTS Soberano’ had a decrease in at least one yield component, while a reduction occurred in all components for cultivar ‘IPR Tangará’. There was an average decrease in NPP, NGP and GMP of 7.9%, 7.6% and 7.2%; 13.4%, 12.8% and 6.7%; and 14.2%, 12.9% and 10.1%, considering the isolates obtained from beans, soybeans and maize, respectively.

Portuguese. RESUMO Macrophomina phaseolina é um patógeno de solo com uma grande variedade de hospedeiros e de difícil controle por práticas culturais. O objetivo deste estudo foi quantificar a severidade da podridão das raízes (SPR) causada por M. phaseolina em cultivares de feijoeiro comum e seu impacto nos componentes de produção. Os experimentos foram conduzidos em casa de vegetação com as cultivares de feijão comum ANFC-9 Agro Norte, BRS Esteio, BRS Estilo, BRS Pérola, FTS Soberano, IPR Campos Gerais, IPR Tangará, IPR Tuiuiú, IPR Uirapurú e TAA Dama. Três isolados de M. phaseolina obtidos de plantas infectadas de feijão, soja e milho foram inoculados nas cultivares de feijão. No estádio fenológico R9 da maturidade da colheita de grãos foram avaliados o SPR e os componentes de produção de massa seca de raízes (MSR), número de legumes por planta (NLP), número de grãos por planta (NGP) e massa de grãos por planta (MGP). Todas as cultivares de feijão foram suscetíveis a M. phaseolina, apresentando redução no NLP, NGP e MGP. A SPR foi superior a 75%, independentemente da origem dos isolados. Na média das cultivares houve decréscimo significativo de 54,3% na MSR quando comparadas aos tratamentos controle. As cultivares IPR Tangará, ANFC-9 Agro Norte, BRS Esteio, BRS Pérola e ‘FTS Soberano’ obtiveram redução em pelo menos um dos componentes da produção enquanto a cultivar IPR Tangará em todos. Observouse decréscimo médio de NLP, NGP e MGP de 7,9%, 7,6% e 7,2%; 13,4%, 12,8% e 6,7%; e 14,2%, 12,9% e 10,1%, considerando os isolados obtidos de feijão, soja e milho, respectivamente.