PATHOGENICITY VARIATIONS OF PUCCINIA-RECONDITA F SP TRITICI AND P-GRAMINIS F SP TRITICI IN WHEAT-GROWING AREAS OF MEXICO DURING 1988 AND 1989

A survey of Puccinia recondita f. sp. tritici in Mexico during 1988 and 1989 indicated the presence of 23 pathotypes. In the Pacific region and Highland Plateau, pathotype TCB/TD predominated both years, followed by TBD/TM. The population was most variable in the eastern lowlands of Mexico to the Texas border. Predominating pathotypes isolated from the collections made from durum wheats and triticales were different from those on bread wheats. Two extra supplemental host sets are proposed for future use in Mexico. Only six pathotypes of P. graminis f. sp. tritici were identified.