First Phenotypic Characterization of the Edible Fruits of Lardizabala biternata: A Baseline for Conservation and Domestication of a Neglected and Endemic Vine

Lardizabala biternata is a culturally valued, endemic vine of the Chilean Winter Rainfall–Valdivian Forest biodiversity hotspot, traditionally harvested for its sweet, edible fruits. Despite its ecological singularity as the sole species in a monotypic genus, the species remains biologically and agronomically understudied, with no formal cultivation systems. There is currently no baseline information on its fruit morphology, which limits the design of conservation strategies and the development of its agronomic potential. This study provides the first phenotypic characterisation of L. biternata fruits, aimed at supporting germplasm evaluation, ex situ conservation, and sustainable domestication of this rare species. A total of 205 fruits were sampled across two seasons and two geographically distant populations. We measured 14 traits, including weight, length, diameter, pulp content, and seed metrics, and analysed morphological variation using t-tests, ANOVA, regression, and principal component analysis or PCA. Fruits averaged 21.0 g in weight, 54.2 mm in length, and 23.8 mm in diameter. Edible pulp constituted 44.4% of total fruit weight and showed strong positive correlations with fruit size, seed number, and seed weight. Significant differences were observed across seasons and populations, with cooler, wetter conditions associated with larger fruits and higher pulp yield. Our findings reveal substantial morphological variability and climate sensitivity, providing a crucial baseline for selecting desirable traits. This work informs ongoing efforts in plant domestication, sustainable agriculture, and the conservation of underutilised species of cultural and ecological importance.