WOUND TYPE IN APPLE FRUITS AFFECTS WOUND RESISTANCE TO DECAYCAUSING FUNGI
‘Golden Delicious’, ‘Granny Smith’ and ‘Red Delicious’ apple fruits were wounded at their equators to give one puncture wound (3 mm diameter x 3 mm deep) and one shallow-slice wound (4.0 mm diameter x 0.4 mm deep) on opposite sides of a fruit. Freshly-made wounds (0 day old) or wounds that were 1 day or 3 days old prior to inoculation were inoculated with 50 or 500 conidia per wound of Botrytis cinerea or Penicillium expansum. After 7 days incubation at 22°C, 1 day or 3 day-old puncture wounds had less decay severity and incidence from either fungus than 0 day-old puncture wounds. Conversely, 0 day-old slice wounds were more resistant to fungal decay, whereas 3 day-old wounds were less resistant. This wound-type effect was found with both inoculum densities and for all cultivars. It occurred in ‘Golden Delicious’ fruits after incubation for 30 days at 3°C. This is the first report of wound type affecting the outcome of fungal infection in apple fruits. Understanding this effect may prove useful in devising a comprehensive theory of host resistance to fungal infection in apple fruit.