Major factors causing variation in bruise susceptibility of apples (Malus domestica) grown in New Zealand

Loss of commercially valuable apples (Malus domestica) as a result of mechanical damage continues to be an issue for postharvest operators. Four important varieties ('Royal Gala', 'Braeburn', 'Granny Smith', and 'Splendour') have been investigated to establish the main influences on susceptibility to bruising. A new measure Of susceptibility is introduced which describes the damage Susceptibility of a population of apples-important from a commercial perspective. Seasonal variation is the main effect on susceptibility. Within a season, late harvest fruit are more susceptible to damage. The only other significant effect was time after harvest for 'Braeburn', with fruit oil day of picking being more prone to bruising. Fruit temperature during handling (for 'Braeburn') and short-term storage (for 'Granny Smith') do not significantly affect commercially relevant susceptibility to bruising. Populations of 'Royal Gala' showed a wide variation in susceptibility to bruising compared with the other three varieties, which were more consistent in their response to impacts.