Estimation of daily carbon demand in sweet cherry (Prunus avium L.) production

In cherry production, the assimilate supply to the fruit is a crucial factor for growth and formation of quality parameters. The assimilate supply per fruit is limited by the relative growth capacity of trees, represented by the leaf area to fruit ratio (LA:F). In the present study, the required leaf area per fruit (LA(demand) [cm(2) fruit(-1)]) of two sweet cherry cultivars, 'Bellise' and 'Regina', was estimated in 2018 and 2019, based on measured and interpolated values of fruit growth and fruit respiration rates. LA(demand) changed daily with an overall increase during fruit development, showing average values in stage III in 2018 and 2019 of 139 cm(2) and 175 cm(2) in 'Bellise', while 199 cm(2) and 212 cm(2) were found in 'Regina', respectively. Estimated LA(demand) and for both cultivars was compared with measurements in cherries grown on girdled branches. In both years, estimated values exceeded measured values. In both years, positive correlation between LA:F and fresh mass, soluble solids content, and coloration was observed. The data obtained can be applied to evaluate the tree's crop load for precise management.