Abstract
With the significant improvement of grape cultivation standardization and the internationalization of product markets in China, grape production is gradually shifting from yield efficiency to quality efficiency. The variety of fruit peels that are easy to separate meets people's needs for convenience and hygiene, and is loved by consumers. Peelability has become one of the quality indicators of many horticultural plant fruits, which has a profound impact on the development of the horticultural industry. The skin-pulp adherence was significantly positively correlated with the cell wall polysaccharide content in the peel and pulp, and significantly negatively correlated with xylanase, xyloglucan endoglycosyltransferase, β-mannanase, pectin methylesterase, and β-galactosidase activity in the peel and pulp. The degree of looseness of the pericarp cell layer may be a morphological indicator of the trait of easy separation of the peel from the pulp. The decrease in total dry matter content of the pulp cell wall may be closely related to the decrease in skin-pulp adherence. Cell wall polysaccharide-degrading enzymes may be a non-major factor causing the difference in skin-pulp adherence. Cluster analysis classified 10 Eurasian grape varieties into 2 categories. The 1st category was easy to peel varieties, such as Flame Seedless, Thompson Seedless, Wuhecuibao, Zaoheibao, Wanheibao, Jinghongbao, Lihongbao, Qiuhongbao and Crimson Seedless. And the 2nd category was difficult to peel varieties, such as Black Balado. This experiment provides a theoretical basis for revealing the physiological basis of the easy peeling trait in grape berries.