CARACTERIZATION OF Rhizoctonia ISOLATES BY MEANS OF ISOENZYMES TECHNIQUE. PANAMA. 1998.

Abstract

The sheath blight of rice causes yield losses estimated between 2.0-45% under climated conditions such as clouded days, high precipitation and high temperatures (Ou, 1984). In Panama the prevalent specie of  Rhizoctonia has not been identified. It has been used molecular markers (isoenzymes) to distinguish among isolates with similar morfology and genetic variability. This research was carried out from July to October of 1998, in the laboratories of IDIAP-Divisa with the objective of identify the species of Rhizoctonia that affects rice plants in Panama. The isolates were collected in rice plots of Alanje, Sona, Penonome, Anton and Chepo, and they were compared with isolates from Tolima, Colombia (Tolima CICA-4, Esparcidor 1, Esparcidor 2) identified as Rhizoctonia solani. The extracted proteins of pure culture of Panamanian and Colombian isolates were analyzed by starch gel electrophoresis, replicated four times. The relative mobility (coefficient RF) of each band of Panamanian and Colombian isolates were compared by the monomorphic isoenzymes: alfa esterasa, fumarase, hexoquinase, leucin aminopeptidase and mannose-6-phosphate isomerase. The relative mobility (RF coefficients) of the zimograms indicates that the Panamanian isolates belong to the specie Rhizoctonia solani and the variants detected in the population are also present in the Colombian population.