• Energy Research

AbstractProfessional and scientific networks built around the production of sweet cherry (Prunus avium L.) led to the collection of phenology data for a wide range of cultivars grown in experimental sites characterized by highly contrasted climatic conditions. We present a dataset of flowering and maturity dates, recorded each year for one tree when available, or the average of several trees for each cultivar, over a period of 37 years (1978–2015). Such a dataset is extremely valuable for characterizing the phenological response to climate change, and the plasticity of the different cultivars’ behaviour under different environmental conditions. In addition, this dataset will support the development of predictive models for sweet cherry phenology exploitable at the continental scale, and will help anticipate breeding strategies in order to maintain and improve sweet cherry production in Europe.

AbstractProfessional and scientific networks built around the production of sweet cherry (Prunus avium L.) led to the collection of phenology data for a wide range of cultivars grown in experimental sites characterized by highly contrasted climatic conditions. We present a dataset of flowering and maturity dates, recorded each year for one tree when available, or the average of several trees for each cultivar, over a period of 37 years (1978–2015). Such a dataset is extremely valuable for characterizing the phenological response to climate change, and the plasticity of the different cultivars’ behaviour under different environmental conditions. In addition, this dataset will support the development of predictive models for sweet cherry phenology exploitable at the continental scale, and will help anticipate breeding strategies in order to maintain and improve sweet cherry production in Europe.

AbstractOur aim was to assess the possible differential effect of increasing temperatures due to global warming on dormancy progression in apricot. The effect of a range of chilling temperatures on vegetative and reproductive bud dormancy progression in excised shoots was examined during two seasons. Temperature treatments were applied in different dormant stages to evaluate the possible interaction of date × temperature for dormancy release in apricot. During sampling, chill accumulated in the field ranged from 0 to 49 chill portions (CPs), corresponding to 0–100% of the chilling requirement (CR) of the apricot selection Z505‐2. Forcing conditions were applied after a 60‐day chill treatment on each sampling date, and rate to budbreak (1/mean time to bud break: MTB−1) was established in vegetative (terminal and lateral) and reproductive buds to determine depth of dormancy. Results showed that the stage of dormancy has a strong influence on the effect of different temperatures on dormancy progression in apricot. For the first time, a non‐linear effect of different chilling temperatures during the dormancy cycle in apricot was obtained, especially in the superior range of temperatures traditionally considered to release dormancy. Thus, introduction of this differential effect could help to improve the models to estimate dormancy release in the context of climate change.

AbstractOur aim was to assess the possible differential effect of increasing temperatures due to global warming on dormancy progression in apricot. The effect of a range of chilling temperatures on vegetative and reproductive bud dormancy progression in excised shoots was examined during two seasons. Temperature treatments were applied in different dormant stages to evaluate the possible interaction of date × temperature for dormancy release in apricot. During sampling, chill accumulated in the field ranged from 0 to 49 chill portions (CPs), corresponding to 0–100% of the chilling requirement (CR) of the apricot selection Z505‐2. Forcing conditions were applied after a 60‐day chill treatment on each sampling date, and rate to budbreak (1/mean time to bud break: MTB−1) was established in vegetative (terminal and lateral) and reproductive buds to determine depth of dormancy. Results showed that the stage of dormancy has a strong influence on the effect of different temperatures on dormancy progression in apricot. For the first time, a non‐linear effect of different chilling temperatures during the dormancy cycle in apricot was obtained, especially in the superior range of temperatures traditionally considered to release dormancy. Thus, introduction of this differential effect could help to improve the models to estimate dormancy release in the context of climate change.

Chilling requirements of temperate fruit species may vary substantially depending on the climatic conditions where they grow. In addition, in a climate change context, a precise knowledge of these requirements and their effect on productivity is critical for choosing the best suited cultivars to assure long-term adaptation under low-chill environments. To date most studies circumvented the analysis of productivity when assessing chilling requirements in different climatic conditions. Thus, the chilling and heat requirements of different sweet cherry cultivars (Prunus avium L.) for breaking dormancy, flowering and fruit set were investigated in two contrasted growing areas in Tunisia: Ain-Drahem (800 m above sea level) and Tibar (328 m above sea level). Additionally, we evaluated several parameters to assess the productivity under these two different conditions. Low chill cultivars showed a higher fruit set in both locations suggesting a better adaption to warm-winter conditions. This three-year study establishes the basis of sweet cherry adaptation under two contrasted locations in Northern Africa.