POPULATION-STRUCTURE AND GENETIC-VARIATION IN NECTRIA-FUCKELIANA

Population structure and genetic variation in Nectria fuckeliana Booth isolated from Picea abies (L.) Karst. in Sweden and Lithuania was stu died using somatic incompatibility tests and DNA fingerprinting. All i ncompatibility pairings between different isolates of N. fuckeliana re sulted in demarcation zones; thus, no vegetative compatibility groups were detected. Each isolate was distinguishable from all other isolate s on the basis of banding patterns produced by amplification of DNA us ing the M13 primer. No country-specific markers were observed. Princip al component analysis of amplified banding patterns separated the isol ates from Sweden and Lithuania into two clusters, showing genetic diff erentiation between the geographical populations across the Baltic sea . An analysis of similarity matrix, calculated by the program SIMQUAL from the numerical taxonomy package NTSYS-pc, confirmed the separation of the isolates into the two groups. Low genetic differentiation was revealed within both the Swedish and Lithuanian geographical populatio ns of the fungus. Local distances in the forest stand (100 m) had no i nfluence on the genetic similarity of the N. fuckeliana isolates (R-2 = 0.003).