Relationship between Fruit Weight and the Fruit-to-Leaf Area Ratio, at the Spur and Whole-Tree Level, for Three Sweet Cherry Varieties

Fruit weight is the main quality parameter of sweet cherries and leaf area/fruit is the most important characteristic influencing fruit weight. The objective of this study was to determine the relationship between Mean Fruit Weight (MFW) and the Fruit Number to Leaf Area Ratio (FNLAR) for 'Bing', 'Van' and 'Lapins', grown under tatura-trellis and vase training systems, at both the spur and whole-tree level. The research was performed through regression analysis with FNLAR as the independent variable and MFW as the dependent variable. There were no significant interactions between training system and cultivar for the effect of FNLAR on MFW at either the spur or whole-tree level. Also, there were no significant differences between training systems. The R 2 for the relationships per cultivar were higher at the whole-tree level than at the spur level. At both levels, 'Lapins' had the highest fruit weight potential and 'Van' the lowest. At the spur level, the slopes of the regression were similar for the different cultivars, but at the whole-tree level, 'Van' was less sensitive. The better fit at the whole-tree level suggests that fruits of a spur are supplied not only by the leaves on that spur, but also from other less fruit-loaded spurs, from non-fruiting shoots and from reserves.