Rambutan Seedling Morphology Under Intact and Divided Seed Treatments With Putative Polyembryony

Rambutan (Nephelium lappaceum L.) propagation requires nursery planting material with adequate vegetative growth. Multiple emergence from a single seed and longitudinal seed division may influence the morphology of seedlings available for transplantation, although multiple emergence alone does not establish polyembryony. This study characterized seedlings associated with intact and divided seeds in five post-emergence groups: Z1 (one seedling from intact seed), PU2 and PU3 (two and three seedlings from intact seed), and PB2 and PB3 (two and three seedlings associated with divided seed). A four-block nursery arrangement was used, with three seeds initially planted per plot. Leaf number, seedling height, stem diameter, leaf area, and root dry mass were assessed in surviving seedlings at 12 weeks after planting. Z1 showed the highest mean leaf number (6.08), height (31.68 cm), diameter (0.395 cm), leaf area (174.07 cm²), and root dry mass (1.88 g). Within the two-seedling class, PU2 and PB2 had similar height means (26.36 and 26.86 cm), whereas PU3 and PB3 differed more clearly in leaf area (111.28 and 135.09 cm²). The results document trait-specific morphological variation but do not establish causal treatment superiority or embryological origin. Multitrait seedling assessment can support nursery selection, while propagation efficiency must be evaluated separately from individual seedling size.