Double-Seeded Fruits in Date Palm (Phoenix dactylifera L.): Morphological Variation and Germination

This study reports the first documented occurrence of double-seeded fruits (DSF) in date palm (Phoenix dactylifera L.), a phenomenon distinct from previously described polyembryony. DSF were observed only in the cultivars ‘Kentichi’ and ‘Deglet nour’, where they occurred at very low frequencies (2.8 × 10−3% and 1.6 × 10−4%, respectively). Morphological observations indicate that DSF arise through partial or complete fusion of two carpels, resulting in syncarpic fruits that are significantly heavier and wider than single-seeded fruits, while fruit length remains unchanged. Germination rates were high and similar in both groups, but seeds from DSF germinated 8 days earlier than those from single-seeded fruits. In contrast, seedlings derived from DSF showed slower early growth. These findings identify DSF as a rare, genotype-dependent developmental variant in date palm and suggest that syncarpy influences fruit morphology, seed allocation, and germination behaviour.