Ampelographic and population structure analysis of grape accessions under eastern anatolia conditions-Türkiye (Tunceli), assessed by SSR markers

Türkiye, which holds an important agricultural spot in the world with its ecological conditions for the cultivation of numerous plant species, has a highly rich genetic potential in terms of the genetic resource diversity of grapes. The Tunceli province, located in the Eastern Anatolia region, is a Turkish region with a harsh terrain structure. This study aims to perform the genetic characterisation and identification of the grape accessions within the Tunceli province, which are not included in the national collection vineyard and are at risk of extinction. In this study, ampelographic characterisation was conducted using a set of 78 descriptors (Vitis species) established by the OIV (Organisation Internationale de la Vigne et du vin) and a Principal Component Analysis was performed. A total of 54 grape samples, consisting of 52 indigenous (from six different regions/populations), 2 reference samples, 1 identical, 1 synonymous, and 4 homonymous cases, were identified using 6 SSR markers. In the structure analysis, it was observed that there was significant gene flow among the Tunceli region populations. Moreover, through the Bayesian analysis, it was determined that the Tunceli region populations (except for the reference population) had a high degree of admixture. In the FCA analysis (with the reference population), it was found that the Akpazar population in particular and, partially, the Mazgirt population, exhibited distinctions. However, genetic distance data also confirmed the distance of the Akpazar population from others. In the RPPs clustering analyses, while the entire population was distributed across 4 different RPPs, 39 accessions (72%) were assigned to one of the RPPs with a membership probability greater than 80%.