The effect of climatic factors on the green leaf volatiles in Cabernet Sauvignon grape

Abstract: 【Objective】Volatiles are one of the essential indictors for grape quality, among which green leaf volatiles (GLVs) are the highest in grape berry. Volatiles are mainly affected by the climatic condi- tions of producing regions, but there are few studies on the key climatic factors affecting the formation of GLVs. Herein, we explored the effect of climatic factors on the GLVs in grapes.【Methods】In this study, Cabernet Sauvignon grape (Vitis vinifera L.) with same maturity level from seven different re- gions were collected in 2018, and the volatiles profiles of the grapes and meteorological characteristics of different regions were analyzed. Further, the key meteorological factors affecting grape GLV con- tents were screened by correlation analysis.【Results】Zhangye and Gaotai regions had longer sunshine duration, larger temperature difference and less rainfall compared with the other regions of Cabernet Sauvignon production. The regions of the Jiaodong Peninsula (Penglai, Laixi) had the shortest sunshine hours, the highest average temperature, and the lowest temperature difference. The meteorological con- ditions of Yinchuan and Huailai regions were similar, with lower sunshine hours than Gansu producing region but better than the Jiaodong Peninsula, and the mean temperature was higher than that in Wuji- aqu, Gaotai, and Zhangye regions but lower than that in Penglai region. Grapes from the seven produc- ing areas could be divided into three clusters according to their volatile characteristics. One cluster in- cluded Zhangye, Gaotai and Laixi regions; another cluster Yinchuan and Huailai regions; and the third cluster Wujiaqu and Penglai regions. Cabernet Sauvignon grapes in Penglai region had a high content of C6/C9 aldehyde volatiles, including 2-hexanal, trans-2-hexenal and trans-2-nonanal. Compared with the other regions, the content of aldehydes in Yinchuan berries was lower, but contents of butyl acetate and 1-octanol were higher than that in the other regions. The contents of ethyl acetate and ethanol in Caber- net Sauvignon berries in Zhangye region were higher than in other regions, and its aldehyde volatiles was higher than in Gaotai, Laixi and Yinchuan, but lower than in Penglai region. 【Conclusion】Large temperature difference between July and September in the growing season is conducive to the synthesis of C6 esters, and high sunshine hours from July to September in the growing season is favorable for the synthesis of C6 alcohols and C6 esters.