Geographical location influence ‘Cabernet Franc’ fruit quality in Shandong province

Grape quality is a key factor in determining wine quality, and it depends not only on management skills, but also on the geographic location of the producing area. In China, Shandong is the province with the largest wine production, and ‘Cabernet Franc’ is widely planted. This study evaluated the ‘Cabernet Franc’ fruit quality in relation to geographical conditions in five ‘Cabernet Franc’ producing districts of Shandong province, China, including Dezhou Aodeman Winery (DZ), Tai’an Zhongqingsongshi Winery (TA), Penglai Longhu Winery (PL), Rushan Taiyihu Winery (RS), and Rizhao Taiyangcheng Winery (RZ). At the time of veraison and maturity, fruit was harvested from five areas, and compared for cosmetic and internal fruit quality. The soluble sugar content in the Rizhao area was rich, and the weight and volume of single fruit were relatively large. The titratable acid of the berries in Tai'an area was high. RNA-seq analysis showed that the number of genes in the véraison stage was 19,571–20,750, and the number of genes in the mature stage was 19,176–20,735. The analysis found that areas with multiple high-quality characteristics tended to have more DEGs (differential expressed genes). And the DEGs in different areas were mainly distributed on chromosome 7, and at least on chromosome 15. DEGs in 5 areas were enriched on 855 GO terms and 116 KEGG pathways during berries development. Among them, it was found that the up/down-regulation of DEGs was related to the formation of berry quality, which helps to explain the impact of environment on grape quality components. In summary, this study is helpful to understand the influence of cultivation location on the quality of 'Cabernet Franc' in different production areas in Shandong province, and further provide a reference for the production of high-quality wine grapes and winemaking.