Genetic Variability in Rhizoctonia solani Isolated from Vitis vinifera Based on Amplified Fragment Length Polymorphism

Problem statement: Rhizoctonia solani is a potential grapevine pathogen. In order to dev elop effective methods of control, it is necessary to do cument its genetic diversity. Approach: The objective of this study was to analyze the genetic variabilit y of R. solani isolated from the rhizosphere of ungrafted V. vinifera var. perlette seedless planted in Sonora, Mexico using Amplified Fragment Length Polymorphism (AFLP). Results: In the selective amplification using eight primer combinations we obtained a total of 446 AFLP markers with a 100% polymorphism. Out of 41 isolates, 36 different AFLP patterns were observed and five were replicates of the same pattern. The dendrogram shows inter- and intrapopulation similarity indexes of 0.26, 0.98 an d 0.31, 0.98, respectively. Six groups emerged from the principal components analysis, five of which were c learly defined, while the other one was spread out. Conclusion: We conclude that R. solani growing in Sonoran vineyards shows a high degree of genetic variability, even under similar environmental condi tions.