Resumo

GUTIERREZ, Bárbara; GONZALEZ, Maria Suleima  e  SALIH L, Alberto. Caracterización de aislamientos de Rhizoctonia Solani Kühn que inducen pudriciones radicales en cultivares de caraota (Phaseolus Vulgaris L.). Bioagro [online]. 2006, vol.18, n.1, pp.063-072. ISSN 1316-3361.

Symptomatic black bean seedlings (Phaseolus vulgaris L) were analized in order to determine the root rot induced by R. solani. Three isolates of R. solani, which showed morphological differences were labeled with the acronyms CRH-V, CRH-F and CRH-558 and utilized. Eighteen beans cultivars were evaluated. Anastomosis groups of R. solani associated to the crop were characterized and their pathogenicity was determined. Significant differences in growth rate were found among the three isolates on PDA. The isolates CRH-F and CRH-558 showed zonation. The isolate CRH-F produced sclerotia under artificial light. Under natural light, all the isolates produced sclerotia. In hyphal reactions, the isolates CRH-F and CRH-558 showed only hyphal contact with AG-1-1 and AG-4, respectively. The isolate CRH-V showed no reaction. There were significant differences for the root and aerial part dry weight among cultivars, isolates and the interactions cultivars by isolates. The isolate CRH-558 caused higher reduction on dry weight and aerial part. In the interaction among isolates and cultivars, MEX -62, Tacarigua and Victoria showed higher root dry weight.

Palavras-chave : Anastomosis group; root rot.