An insular in situ Coffea arabica resource from Rapa Nui (Easter Island): simple sequence repeat (SSR) uniformity and biochemical evaluation of material consistent with the Typica lineage
摘要
Rapa Nui (Easter Island) hosts long-established Coffea arabica populations growing under subtropical island conditions outside the conventional coffee belt. To document this insular material from a plant genetic resources perspective, we characterized two accessions (Tahai and Kainga) using 11 simple sequence repeat (SSR) loci and quantified caffeine, trigonelline, and total chlorogenic acids in green beans by high-performance liquid chromatography (HPLC). Both accessions showed identical allele sizes across all loci, indicating no detectable differentiation between the two sampled localities at the marker resolution used here. Green-bean composition showed caffeine of 8.87–10.04 mg g−1, trigonelline of 12.82–3.35 mg g−1, and total chlorogenic acids of 17.53–20.43 mg g−1, a profile compatible with sweetness-related and mild-acidity descriptors reported during professional cupping. These results identify Rapa Nui coffee as a geographically isolated Arabica genetic resource of conservation interest and support further documentation of this insular germplasm. Because the present study was limited to two accession-level samples, broader island-wide sampling, voucher deposition, and higher-resolution genotyping are required before stronger inferences are made regarding lineage identity and diversity.