## 1 Introduction  
The peach (_Prunus persica_ ([PERSON]) has become an important economic crop due to its soft and juicy flesh, attractive aroma and enriched nutrition, and it has been grown extensively at home and abroad [1]. As the originating country of the peach, China holds a large number of wild relatives and landradares [2]. 'Chinese Cling', the most influential founder in peach-breeding history, has derived many excellent cultivars such as 'Elberta', 'J.H. Hale', 'Okubo' and 'Hakuho' [3]. The elite commercial peach cultivars planted in Shanghai, such as 'Hujingmilu' (HJML), 'Xinfengmilu' (XFML) and 'Jinxiu' (JX), are also excellent offspring of 'Chinese Cling'. These cultivars are popular in Shanghai for their high quality and were cultivated in 3100 hectares in 2021, accounting for approximately 82% of the total peach-cultivated area in Shanghai (data source: Shanghai Agricultural Technology Extension Service Center). Aroma is an essential factor to determine consumers' preference, which has received great attention from geneticists and breeders in recent years [4, 5]. The aroma profiles in fruit result from the interactions of many volatiles. Currently, more than 100 volatiles have been identified in peaches, mainly including aldehydes, alcohols, esters, lactones, terpenes and ketones [6; 7]. However, the compositions and content of volatiles are influenced by genetic backgrounds, fruit maturity and cultivation conditions. For instance, aldehydes and alcohols are the major contributors of VOCs in immature fruits and their contents decrease gradually during maturation, while the contents of lactones increase with peach fruit maturation [8]. Studies on several varieties have shown many differences in the composition and content of volatiles. [PERSON] et al. have reported that the Chinese wild peach 'Wutao' has the highest content of total volatiles, while 'Ruipan 14' and 'Babygold 7' show high contents of lactones, and cultivars of American and European origin mainly contain high levels oflinalo [7]. Several studies have also shown that cultivation conditions can also influence the composition and content of volatiles, such as fertilization and bagging [9; 10; 11]. Although more than 100 VOCs can be detected in peaches, only around 25 of them significantly contribute to flavor quality, and these are recognized as characteristic compounds [12]. The odor activity value (OAV) is commonly used to evaluate the contribution of a compound to the overall aroma, and it represents the ratio of the actual concentration in the sample to the threshold value in water, and was first proposed by [PERSON] [13]. Compounds with OAV \(\geq 1\) are not only considered major contributors to flavor, but also good indicators for the breeding of good-quality peaches. Gas chromatography-mass spectrometry (GC-MS) is a commonly used technique that takes advantage of the high separation ability of GC and the superiority of mass spectrometry in the identification of substances, which allows it to be applied with high sensitivity and precision in the qualitative and quantitative analysis of VOCs in samples [14]. However, due to the complexity of most sample matrices, this method requires tedious and time-consuming sample pretreatment before analysis while working under vacuum conditions, making it unsuitable for rapid characterization studies of VOCs in complex samples [15; 16]. Ion mobility spectrometry (IMS) is an atmospheric analytical chemistry method for the detection and identification of different types of substances based on the mobility of gas-phase ions in a weak electric field [15]. GC-IMS integrates the high separation ability of GC with the high sensitivity and fast response of IMS. Compared to GC-MS, it has the advantages of having a lower detection limit, no pre-treatment, convenience and can be operated at atmospheric pressure, which can maximize the authenticity of flavor in samples and reflect the original flavor information [16; 17].