Abstract: 【Objective】 Table grapes with early maturity and fragrant flavors play an important role in fruit industry and are more attractive to consumers when compared with other cultivars. Comprehensive study on the evolution of volatile compounds of early maturing variety is significant for breeding and evaluation of new cultivation technique.【Method】This study used headspace solid phase micro-extraction method and the technology of gas chromatography-mass spectrometry to analyze the changes of volatile compounds and related metabolic pathways of grape berries (V. vinifera cv. Ruidu Xiangyu), which were sampled from 3 weeks to 12 weeks past blossom. In the meantime, the method of PCA was used to clear the relationship between developmental stages and volatile compounds. 【Result】 ‘Ruidu Xiangyu’ came into the stage of verasion at 5 weeks after blossom and into the stage of maturation at 9 weeks after blossom. The fragrant monoterpenes like linalool, nerol, geraniol, citronellol and terpineol accumulated differently at the full developmental process. The maximum content of nerol and geraniol showed up at the beginning of maturation while linalool and terpineol in the middle of it. And the content of citronellol changed irregularly at maturation. E-2-hexenal and hexanal are the main C6 compounds at maturation, and their content went to the peak after verasion and then decreased. Z-3-hexenal mainly existed at young fruit period, of which the content was low at verasion. Additionally, the content of norisoprenoids like β-lonone, damascenone and aromatic compounds like benzaldehyde was very low at maturation. Considering the content change of various compounds, terpenes accumulated differently at different developmental stages and decreased at maturation. Esters mainly accumulated at young fruit period and postveraison stage while aldehydes and ketones were evident at preveraison stage. C6 compounds increased during veraison and then decreased with alcohols. Aromatic compounds and volatile acid accumulated at preveraison and postveraison stage respectively. The key stages for content change are also different to various volatile compounds. Verasion is the key stage for aldehydes and ketones, while major esters and aromatic compounds change before it, and terpenes, C6 compounds and volatile acid change after it. 【Conclusion】Our study indicates that the Z-3-hexenal route from splitting linolenic acid is active at early stage. Other Lipoxygenase (LOX) routes and synthesis of terpenes become active during veraison while accumulations of most compounds become weak at maturity. The key stage for the formation of its characteristic aroma is from verasion to maturity. Major fragrant terpenes accumulate differently in ‘Ruidu Xiangyu’ grape and linalool and α-terpineol decrease later than other monoterpenes. Considering C6 compounds and terpenes, properly delayed harvest will be better for the realization of its fragrance.

Key words: grape, variety with early maturity, volatile compounds, PCA