Evaluating morphological diversity in male date palm genotypes from Tunisia: insights from vegetative and reproductive descriptors for selection criteria

Abstract Date palm cultivation is vital for sustaining agricultural economies in arid regions, where efficient pollination is essential for optimal fruit yield and quality. This study analyzed 47 morphological parameters in 10 date palm pollinators, including 32 vegetative and 15 reproductive traits, which were treated separately. The correlation matrix revealed strong positive correlations, such as pollinator vigor with palm angle and cornaf persistence with fibrillium hardness. Principal component analysis (PCA) identified eight highly discriminating vegetative traits (e.g. total palm length, palm angle) and six reproductive traits (e.g. spathe length, spikelet number). Genetic distance analysis showed close values (0.233–0.25), thereby indicating significant morphological diversity. Hierarchical classification grouped genotypes based on phenotypic similarities, with vegetative traits exhibiting greater dissimilarity (0.225–5.85) than reproductive traits (0.1–3.85). Heatmap analysis revealed that dense crowns correlated with long spikelets, while wide spines were associated with dense inflorescences. These findings underscore the importance of morphological traits for selecting and distinguishing pollinators, enhancing pollination efficiency, and ensuring sustainable production in date palm-dependent regions.