Multivariate analysis of morphological diversity in carob pods (Ceratonia siliqua, Fabaceae) among different accessions collected from Algeria

Sixty-four carob accessions growing in 17 localities covered a wide geographical area of Algeria, and the primary objective of this study was to assess the morphological variability of pods and seeds, as well as to identify potential phenotypic variation that could be used in selecting superior carob cultivars for cultivation in Algeria’s diverse agro-ecological zones. Morphological variability was assessed on the basis of 12 pod and seed traits. ANOVA showed a large significant phenotypic variation between accessions for all traits studied, demonstrating considerable phenotypic diversity. Principal component analysis (PCA) was used to examine the relationship between these traits, leading to the classification of these accessions into seven distinct groups (Clusters I-VII), revealing considerable phenotypic diversity. The first two dimensions of the model accounted for 71.4% of the total variation, with the first component explaining 47.7% of the variation, primarily driven by pod traits, while the second component was primarily influenced by seed traits. The correlation analysis established between the variables provided a specific understanding of how this approach can be useful for the development of a breeding program, aimed at increasing seed yield for the agri-food industry, selecting accessions characterized by narrow, thin, light pods and short pods at the last position.