Influence of Bud Drop, Flowering Period and Fruit Set on Chill Units of South Marmara in High Chilling Requiring Apricot Cultivars

One of the most important problems to be faced in some apricot cultivars consists in the poor or irregular productivity that are widespread in South Marmara (Çanakkale) apricot growing. This phenomenon could be linked to apricot of flower bud due to chilling requirements would appear to play a determining role. The influence of chilling on flowering period, bud drop and fruit set of apricot cv. ‘Hasanbey, Hacıhaliloğlu, Kurukabuk, Çataloğlu, Hacıkızı, Çöloğlu, Kabaaşı, Alyanak and Etembey' and the chilling requirements were studied. Daily temperatures (each hour) were recorded in Çanakkale, which is close to the experimental orchard. Accumulated chill units were calculated from the beginning of November to the end of February during five consecutive years (2008–2013). Heavy bud drops (more than 80 % in ‘Hacıhaliloğlu, Çöloğlu and Alyanak' cultivars) was recorded. The heavy bud drops, together with the low fruit set, indicate that their fruit set (between 0.3–6.3 %) is unacceptable in apricot cultivars. High chilling requiring nine apricot cultivars create problems such as prolonged flowering period, more flower buds drop and low fruit set. These phenomena affect total productivity.