Exploration and morphological characterization of local yams from the Tanimbar Islands, Maluku, Indonesia

The Tanimbar Islands in Maluku Province, Indonesia, are a significant distribution center for Dioscorea alata L. However, exploration and morphological characterization of this species remain limited. This study aimed to (1) identify and analyze the morphological characteristics of local D. alata from the Tanimbar Islands and (2) determine the distinguishing characteristics for each D. alata accession observed. The exploration of D. alata was followed by ex-situ cultivation. Morphological characterization was conducted on 15 accessions using 16 morphological traits based on the International Board for Plant Genetic Resources (1997) descriptors. Hierarchical Cluster Analysis (HCA) revealed two primary groups with a dissimilarity coefficient of 33%. Group one consisted of the DA-01 and DA-02 accessions, while all other accessions formed group two. Notably, accession DA-11 within group two displayed a 26% difference in morphological traits compared to other group members. Principal Component Analysis (PCA) identified 21 significant characteristics that contributed to 42.9% of the total diversity. Accession DA-01 exhibited unique characteristics such as tuber cracking, while DA-02 stood out for stem diameter and leaf width. Additionally, DA-13 displayed unique root positions on the tuber surface, DA-14 exhibited distinctive leaf apex coloration, and DA-15 showed a unique inner tuber skin color. This study underscores the morphological diversity of D. alata in the Tanimbar Islands, providing valuable insights into its genetic resources.