Behavior and morphometric characterization of local and introduced cultivars of sweet cherries (Prunus avium), tested in a multi-site trial in Tunisia

Abstract

Sweet cherry (Prunus avium L.) is a hardy species able to be adapted to various soil and climatic conditions; but its development is hampered by some physical, climatic and physiological constraints. The objective of this work is to study the behavior of 11 sweet cherry cultivars in three experimental sites characterized by different pedo-climatic conditions in the North West of Tunisia (Ain-Draham, Bousalem and Tibar) and to explore the "Genotype -by- environment" interaction to select the most suitable cultivar for the mild wintry climate of North West Tunisia. Six cultivars are of known origins (1 cultivar from Tunisia, 1 cultivar from Germany, 1 cultivar from France and 3 cultivars from Canada) as well as 5 cultivars are of unknown origins. Morphometric measurements were made on the leaves, flowers and fruits. Univariate statistical analyses comparing the obtained means at each experimental site were performed. To study the « Genotype x Environment » interaction (GxE), an inter-site analysis of variance was performed on the common cultivars to both Tibar and Ain-Draham sites. The decomposition of the “GxE” interaction by using Wrike's ecovalence showed that, firstly the French cultivar “Moreau” and secondly the Canadian cultivar “Van”, are the two main cultivars influenced by the environmental conditions for the most studied morphometric characteristics. Multivariate analyses based on cluster analysis and principal component analysis was performed on the mean values ​​of all the measured parameters for the each cultivar-site combinations. Napoleon, Van, Moreau, Stella, Bouargoub, BV9 and BV11 were best adapted cultivars to the climate with mild winter.