An exothermic process involved in the late spring frost injury to flower buds of some apricot cultivars (Prunus armenica L.)

Freezes during early spring can injury flower buds of apricot (Prunus armeniaca L.). The reduction in apricot production owing to cold injury to flower buds can be significant and serious problem for apricot growers and is common and among commercial production in some regions of the Turkey. Therefore, in this study, using Differential Thermal Analysis (DTA), freezing point (FT, LTEs), and/or freezing injuries in flower buds were determined at different development stages, such as first white, first bloom, and full bloom. Some domestic and foreign apricot cultivars tested were Hasanbey, Hacıhaliloğlu, Şekerpare, Erzincan Tokaloğlu, Mihralibey, Şalak and Roksana. With the development of flower buds, the frost tolerance of buds decreased, which indicates that their freezing point increased, and the frost tolerance of buds changed according to different phonological stages and apricot varieties. Additionally, cold tolerance of flower buds gradually decreased while their sensitivity to first white, first bloom and full bloom temperatures increased. The apricot cultivars were classified as hardy (Hacıhaliloğlu and Şalak), moderately hardy (Hasanbey, Şekerpare and Roksana) and least hardy (Erzincan Tokaloğlu and Mihralibey). The evidence illustrates that this investigation will provide a better comprehension of apricot frost tolerance and will assist to apricot growers in decision-making of frost control practices.