11 research outputs found
Studies on the genetic diversity of primary and secondary infections of Plasmopara viticola using RAPD/PCR
In 1998 and 1999 isolates from primary and secondary infections of Plasmopara viticola (downy mildew) were sampled from several grapevine varieties. Fungal isolates were taken from the same vineyard located in Wurttemberg/Germany. Using the random amplified polymorphic DNA (RAPD) technique as an initial screening for genetic variation within P. viticola isolates, different molecular fingerprint patterns were obtained. Out of 48 isolates of primary infections 27 (1998) and 29 (1999) different genotypes were found. In contrast, variability of secondary infections was lower: about 9 in 1998 and 14 in 1999 different genotypes out of 48 isolates. The high genotype diversity in primary infections and the low level of genotype diversity in secondary infections strongly suggests environmentally directed selection