Short communication.Validation of a leaf area estimation model for sweet cherry

A leaf area (LA) estimation model developed in a temperate climate for sweet cherry (Prunus avium L.) was tested for validation on ʹReginaʹ trees on two rootstocks of varying vigor, ʹGisela 5ʹ (Gi5) and ʹGisela 6ʹ (Gi6), in a cool temperate climate (the Great Lakes region of North America). To determine the degree of accuracy of the model, actual LA values measured by digital planimeter were plotted against predicted LAs calculated by the model. The relationships (r2 values) were very high and varied little between rootstocks (r2 = 0.9886 for Regina/Gi6 and r2 = 0.9849 for Regina/Gi5). This study demonstrates that the model is valid for use by cherry researchers in different growing regions and for rootstocks that impart different levels of vigor scion, such as ʹReginaʹ.