RESISTANCE TO BOTRYTIS-CINEREA IN PISTILLATE GENOTYPES OF THE CULTIVATED STRAWBERRY FRAGARIA-ANANASSA

Four strawberry families which segregated for pistillate and hermaphrodite flowers were assessed for their susceptibility to Botrytis cinerea (grey mould). Clonally propagated plants were grown in a glasshouse and the flowers sprayed with a conidial suspension of the fungus. In extreme cases the disease resulted in necrosis of the flowers and pedicels before fruit development had begun. This occurred in a significantly higher proportion of hermaphrodite than pistillate flowers. Necrosis due to B. cinerea in unripe and ripe berries was also significantly greater in plants with hermaphrodite flowers. Differences in susceptibility between families were also observed, but there was no interaction with flower sex. It is proposed that the reduced incidence of necrosis on the flowers and fruit of pistillate plants is due primarily to the absence of anthers, which in hermaphrodite flowers provide a major route for B. cinerea to enter the developing receptable.