The knowledge of genetic variability of Colletotrichum lagenarium isolates is highly important for the success of the breeding programs for resistance to cucumber anthracnosis. Nineteen isolates of C. lagenarium obtained from commercial fields of cucumber in Zona da Mata and Agreste of Pernambuco State, Brazil, were compared by isoenzyme electrophorectic analysis in polyacrylamide gel at 7%, using the systems esterase, acid phososphatase, alkaline phosphatase and malic dehydrogenase. The evaluation was based on the number and position of observed bands, calculating the relative motility. The genetic distances and similarities were summarized by grouping analysis, using the software NTSYS. The analysis showed variation in number and position of the bands on gel, for each studied system, revealing phenotypic differences in the population. The enzymes malic dehydrogenase and alkaline phosphatase showed lower polymorphism, while sterase and acid phosphatase were more polymorphic. The grouping analysis allowed to separate the genotypes in five different groups: 1 (CL1, CL3 and CL22), 2 (CL14), 3 (CL4, CL38, CL15, CLl7, CL5, CL8, and CL10), 4 (CL28) and 5 (CL23, CL20, CL34, CL36, CL35, CL37, and CL16). The lower genetic similarity index (27.3%) was observed among isolates CL1 and CL20, CL35, CL37 and CL16 and the higher (100%), was observed among isolates CL5 and CL8; CL5 and CL10; CL8 and CL10; CL35 and CL37; CL35 and CL16 and, CL37 and CL16.
Cucumis sativus; anthracnosis; isoenzymes; electrophoresis
