Resumo

FLORES-MOCTEZUMA, Hilda Elizabet; MONTES-BELMONT, Roberto; ROGEL-HERNANDEZ, Marco Antonio  e  MARTINEZ-ROMERO, María Esperanza. Genetic diversity of Sclerotium rolfsii Sacc. in Mexico. Rev. mex. fitopatol [online]. 2008, vol.26, n.1, pp.7-14. ISSN 2007-8080.

Twenty isolates of Sclerotium rolfsii from different regions of Mexico were confronted amongst themselves to evaluate their genetic diversity. This trial was made using potato-dextrose-agar media to establish mycelial compatibility groups (MCG) and then they were compared with eleven isolates of a worldwide collection of this fungus. Each isolates showed a different MCG pattern, and when they were confronted with isolates from the world colection MCG 33 prevailed over 8 isolates from Mexico. It seems that there is no relationship between either MCG and the host or geographical area. The variation in the internal transcribed spacer (ITS) regions of the ribosomal genes in the same isolates, was determined by RFLP using the restriction enzymes Rsal, HpalI, Sau3AI, and MspI. Combined banding patterns for the four enzymes were used to characterize isolate variation and to compare these results with the combing banding patterns of the eleven isolates from the worldwide collection. It was found that twelve isolates from Mexico belong to some of the RFLP-ITS groups of the worldwide collection of Harlton et al.; the other eight isolates belong to a new group characteristic of Mexico.

Palavras-chave : Genetic variability; southern blight; RFLP-ITS; mycelial compatibility groups.

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