Apple pollination: A review

Pollination is a key event for fruit set. Worldwide, there has been an increasing interest in apple pollination. Apple pollen grains are elliptical and tricolpate. Pollen germination is highly dependent on temperature. Most apple pollination occurs through cross-pollination; however, some cultivars have been reported to self-pollinate. Most apple cultivars have a gametophytic self incompatibility (GSI) system; however, others are semi compatible, or fully self compatible. The most common insect pollinator of apple is the honey bee. Other effective pollinator species include Hymenopterans, Dipterans and Coleopterans. Wind seems not to be an effective mechanism for pollination. Environmental conditions such as temperature, rain and high wind speed negatively affect pollination. This article reviews recent developments in our knowledge of apple pollination focusing on recently developed cultivars growing in the tropics.