Genetic diversity between Botrytis cinerea isolates from unstored and cold stored kiwi fruit

Ninety isolates of Botrytis cinerea collected from kiwi fruit in orchards and in cold storage were compared phenotypically and genetically. The phenotypic characters evaluated were conidia germination, germ tube length and mycelial growth at 0degrees and 20degreesC. At 20degreesC the two populations showed slight differences but, at 0degreesC, isolates from cold storage appeared to grow significantly faster than isolates from orchards. Isolates were then scored with six genetic markers with the aim of investigating population, genetic structure and the mode of reproduction. We detected no genetic differentiation between isolates from orchards and those from cold storage. This suggests that low temperature adaptation of B. cinerea isolates does not have a genetic basis. By contrast, we found great intra-population genetic diversity, observations suggesting the occurrence of genetic recombination which follows sexual reproduction or alternatively of parasexuality.