Abstract

Pitting caused by impact bruising is one of the main causes of deterioration of sweet cherry (Prunus avium L.) in commercial production. Different levels of crop load were obtained on four-year-old central leader 'Van' sweet cherry trees. The natural crop load (25 spurs/m, with no spur thinning) was compared with a spur thinning treatment (20 spurs/m) and fruit thinning treatments (3 to 4 fruits/spur or 1:2 non-fruiting/fruiting spur ratio). The incidence of impact bruising was evaluated at harvest by dropping a 10 g steel ball from a height of 5 cm on fruit from the different treatments. The natural crop load was 120 to 130 fruits/m, while spur thinning to 20 spurs/m gave ?100 fruits/m and the fruit thinning treatments gave 59 to 88 fruits/m. The fruit thinning treatment of 3 to 4 fruits/spur produced the largest fruit with high soluble solids concentration and was the most resistant to impact bruising. The tree: fruit parameters for this crop load were 3.0 leaves/fruit or around 60 fruits/m. The postharvest evaluation showed that both fruit thinning treatments yielded the lowest percentage of pitting after 50 days in modified atmosphere packaging, simulating commercial manipulation. However, the fruit thinning treatment of 3 to 4 fruits/spur was significantly more susceptible to fruit cracking after storage.