SSR genotyping of 200 tea (Camellia sinensis) clones obtained by selection and DNA barcoding of 12 varietal registration candidates

Genotype and cultivar identification is essential for conserving tea genetic diversity within plantation ecosystems and ensuring the sustainability of high-quality tea production. This study represents the first large-scale genetic characterization of 200 elite varietal candidate tea (Camellia sinensis) clones, which were pre-selected from 2,034 genotypes originating from the Eastern and Western Black Sea regions of Türkiye. Eight polymorphic simple sequence repeat (SSR) markers located near loci associated with catechin content, including epicatechin (EC), epicatechin gallate (ECG), epigallocatechin (EGC), and epigallocatechin gallate (EGCG), were employed. SSR profiles were generated for all 200 tea clones cultivated in control plots at the National Tea Gene Bank, and the resulting data were additionally used for DNA barcoding of 12 varietal candidate tea clones currently under registration. Among the evaluated markers, TM412 (EGC) exhibited the highest polymorphism information content (PIC = 0.8816), whereas TM376 (EC) showed the lowest (0.4321). Notably, TM412 (EGC) and TM399 (ECG) displayed high PIC values, indicating their strong discriminatory potential for Turkish tea genotypes. The findings indicate that Turkish tea germplasm possesses substantial genetic diversity, and some markers may be effectively utilized in variety registration and breeding efforts. This study presents the first comprehensive molecular characterization of tea genetic resources in Türkiye. It contributes to the long-term conservation of selected clones and supports the variety registration process through DNA barcoding and a QR code-based traceability system. The genetic dataset generated in this work contributed directly to the establishment of Türkiye's first and the world's fifth-largest tea gene pool in Rize Province, providing a valuable reference for strengthening tea genetic resource conservation and breeding programs at both national and global scales.