VARIATION IN PATHOGENICITY AND DNA POLYMORPHISM AMONG BOTRYTIS-CINEREA ISOLATES SAMPLED INSIDE AND OUTSIDE A GLASSHOUSE

Colonies of Botrytis cinerea were obtained from spore samplers placed inside and outside a glasshouse with a rose crop. Pure cultures were m ade from five colonies collected on one sampling date every month thro ughout the year. These isolates were tested for germination on water a gar and for pathogenicity on gerbera and rose petals. The germination rate of the conidia on water agar varied between 60 and 99%. Pathogeni city of the isolates on gerbera and rose flowers ranged from 14 to 166 % relative to reference isolate Bc16 and varied among isolates collect ed on the same day as much as among isolates collected in different mo nths. The pathogenicity of the isolates on rose flowers was overall hi gher than on gerbera flowers. Random amplified polymorphic DNA (RAPD) analysis was performed on 30 selected isolates with different relative pathogenicity, collected both inside and outside the glasshouse. Almo st all of the isolates were genetically different. No correlation was found among pathogenicity, sampling time, sampling place, and RAPD pat terns. Results are further evidence for the statement that B. cinerea inoculum in glasshouses continuously originates from many different so urces in their vicinity.