COMPARISON OF VEGETATIVE COMPATIBILITY TYPES IN ITALIAN AND SWISS SUBPOPULATIONS OF CRYPHONECTRIA-PARASITICA

Tester isolates of 20 vegetative compatibility (vc) types from 11 Ital ian subpopulations and tester isolates of 26 vc types from five Swiss subpopulations of Cryphonectria parasitica were compared by two differ ent vc rest methods. A total of 31 different vc types was identified; 15 vs types were common to both countries, five Italian vs types were not found in Switzerland and 11 Swiss vs types were not found in Italy . These 31 vc types were labelled with the acronym EU, followed by pro gressive numbers and may constitute the base for a common European nom enclature. The ve type EU-2 was the most common vc type in both countr ies and dominated in all Swiss and in seven Italian subpopulations. Th e vc types EU-1 and EU-5 were found primarily in northern Italy and Sw itzerland, while EU-10 and EU-12 were most common in southern Italy. T he diversity of:ve types was greater in the subpopulations of Switzerl and and northern Italy than in the subpopulations of southern Italy. T he geographical distribution of vc types in Europe should therefore be taken into consideration for biological control measures of chestnut blight and quarantine regulations.