Analysis of variability in Pistacia vera L. fruit genotypes based on morphological attributes and biometric techniques

In this study, numerous properties of pistachio tree (Pistacia vera L.) varieties such as WAHIDI, UZUN, RED ALEPPO, OUHADI, AYIMI, KIRMIZI, MOMTEZ, ACHOURY, KERMAN, EL-GUETAR, MATEUR, and NOURI were determined. Physical and mechanical properties of pistachio fruit [(length/width) fruit ratio, fruit form, color of pedicel scar, form of pedicel scar, relief of pedicel scar, percentage of empty fruits, number of knotted flowers/fruit cluster, fruit drop rate, number of fruits/cluster, and percentage of mature fruits] were evaluated. Principal component analysis was applied in the aim to identify the importance of studied parameters and their corresponding correlations. On the basis of obtained results, the most influential fruit character of first principal component (contribution rate = 35%) was relief of pedicel scar, and the most dominant fruit attribute of second principal component (contribution rate = 22%) was form of pedicel scar. Circle of correlation confirmed first that fruit maturity is associated with pistachio size development. Second, to have a high fruit yield, the relief of pedicel scar must be low. Furthermore, Bayesian Networks method was showed in the aim to reveal the relationships between different parameters. Finally, the dendrogram of selected pistachio varieties demonstrates that a high similitude existed between varieties with a similarity value of 0.64. In fact, the dendrogram of pistachio fruit revealed that all studied accessions were divided into three main clusters. Hierarchical clustering revealed that a strong connection existed between physiological and yield traits. These results illustrate a possible use of desired features at least in various infra-specific investigations in P. vera L. to highlight hidden relationships between varieties.