Flowering of Sweet Cherry (Prunus avium L.) Cultivars in Cieza, Murcia, Spain

Interest in sweet cherry (Prunus avium L.) production is increasing in the region of Murcia, Spain. In the area of Cieza, Murcia, the flowering period of 35 cherry cultivars was recorded for four years in an ex situ collection subjected to drip fertigation. The flowering periods of 2008 and 2009 were compared and connected to chilling hours below 7 degrees C and to chill units (CU) (Richardson, 1974). In Cieza, 1,293 CU in 2007/2008, and 876 CU in 2008/2009 were recorded. There, a Mediterranean climate is characterized by mild winters and hot, dry summers. In this environment, cherry cultivars have been classified in groups of diverse sensitivity to chilling relative to changes from 2007/08 to 2008/09. Concerning the early and the middle flowering periods, 'Mister Early', 'Primulat', 'Sweetheart', 'Somerset' and 'Sylvia' had a low sensitivity to chilling changes. For late flowering, 'Early Lory', 'Grace Star', 'Chelan', 'Garnet', 'Satin', 'Samba' and 'Santina' were less sensitive to prior chilling changes. Since the Cieza area produces mainly early stone fruits, local growers are increasingly interested in early sweet cherry production. Key criteria for sweet cherry cultivars should focus on varieties with early and middle flowering times to produce enough flowers for a normal early crop.