Genetic variability in Sphaerotheca fusca as determined by AFLPs: the case of race 2 as a causal agent of powdery mildew in melon

摘要

Genetic differentiation of races of the most important causal agent of powdery mildew, Sphaerotheca fusca, is an important goal to design appropriate selection strategies for melon breeding. We have used AFLP markers to characterize nine isolates, seven of them identified as belonging to race 2 and two of race 5. Our results showed that AFLPs reveal a higher rate of polymorphism than other molecular markers (i.e. ITS, ISSRs and RAPDs) although AFLPs did not showed a good correlation between the molecular data and the physiological races probably due to the low number of markers analyzed. Interestingly, AFLPs were able to discriminate between isolates different geographical origins, what was not possible by means of other molecular markers. These results indicated the usefulness of the AFLPs as markers for the study of genomic variability in Sphaerotheca fusca.