Multivariate analysis of phenotypic diversity in Moroccan orange accessions (Citrus sinensis L. Osbeck) from the El Menzeh collection

The morpho-pomological characteristics of 65 traditional orange accessions (Citrus sinensis L. Osbeck) were studied in the plantation of the El Menzeh experimental field of INRA. In total, 45 traits were evaluated from each accession’s leaves, fruits, and seeds according to the IPGRI descriptors. The results highlight significant diversity among the analyzed genotypes based on the measured traits (ANOVA, P < 0.01). Maximum variability was observed in the juice colour index, pulp colour index, and epicarp thickness, with coefficients of variation exceeding 74 %. Most significant correlations were found between traits related to fruit size and thickness and leaf dimensions. Morphological traits were classified by mixed principal component analysis (PCAmix) into 17 components, explaining 81.4% of the total variation. The parameters with the highest discriminant values were those relating to leaf dimensions, fruit size, and juice content. The ascending hierarchical classification divided the 65 orange accessions into five main groups. Finally, it can be affirmed that the collection of orange trees presents a satisfactory overall phenotypic diversity. This study identified promising orange tree genotypes with desirable commercial traits, such as high juice content.