## 1 Introduction  
Tea is one of the three major non-alcoholic beverages in the world and is widely popular due to its potential health benefits and unique flavor profiles [1, 2]. Black tea, a fully fermented tea, is one of the six major tea categories in China. It is characterized by red-colored liquor, red- hued leaves, a sweet taste, and a mellow flavor. Black tea is the most favored tea type among consumers, accounting for approximately 78% of total global tea consumption [3]. Hunan is one of the primary black tea producing provinces in China, and the black tea produced there is well known for its distinct floral aroma [4, 5]. Rucheng Baimao (_Camellia pubescens_), native to Rucheng County, Hunan Province, is one of the four rare wild tea tree varieties in Hunan. It is named for the white hairs that cover the surface of its leaves. It is rich in biochemical components, and is especially high in tea polyphenols and catechins, making it an excellent raw material for producing high-quality black tea [6, 7, 8].  
Aroma is a crucial factor in evaluating the quality of black tea and significantly influences consumers' purchasing decisions. Thus, identifying the aroma compounds in black tea has drawn the interest of many researchers. Studies have indicated that floral, sweet, and fruity aromas are typical aroma characteristics of black tea [9]. Currently, more than 600 volatile components have been detected in black tea [7]. Components such as linalool, phenethyl alcohol, phenylacetaldehyde, methyl salicate, and geraniol have been identified as key aroma substances in black tea, they possess characteristics such as floral, fruity, and sweet aromas, and have a positive impact on the aroma quality of black tea [10, 11, 12]. However, the aroma quality of tea is significantly influenced by seasonal factors [13]. Due to differences in the external growth environment, including light, temperature, and humidity, the freshly picked tea leaves exhibit different enzymatic and chemical properties, which results in variations in tea quality [14].  
As a high-quality and characteristic tea tree resource for making black tea in Hunan Province, Rucheng Baimao has also been explored for its volatile components. [PERSON] et al. compared the aroma characteristics of black teas made from three characteristic tea tree varieties in Hunan. The results showed that the black tea made from Rucheng Baimao had a long-lasting floral aroma, and its volatile components were mainly alcohols with sweet and floral-fruity aromas [15]. Additionally, studies have compared the key aroma substances of 'Baimaocha' black tea from different origins, and the results show that methyl salicate is the main contributor to the fresh aroma characteristic of Rucheng Baimao black tea [7]. Therefore, previous studies on the aroma quality of Rucheng Baimao black tea mostly focused on comparisons with other varieties. However, to date, no research has been reported on comparing the volatile components of Rucheng Baimao black tea in different seasons. In recent years, Rucheng County has been committed to fully exploiting the excellent characteristics of Rucheng Baimao, focusing on developing mid- to high-end black tea and white tea in late spring, summer, and autumn, with the aim of vigorously promoting the sustainable development of the tea industry in Rucheng County [16]. Therefore, exploring the differences in the volatile components of Rucheng Baimao black tea in different seasons is of great significance for regulating the aroma quality of Rucheng Baimao black tea and for the sustainable development of the tea industry. Furthermore, as the seasons for black tea production in Rucheng County are spring, summer, and autumn, this study utilizes sensory evaluation, HS-SPME-GC-MS, and combines with roavy analysis to explore the differences in the aroma quality and volatile components of Rucheng Baimao black tea in these three seasons. The purpose is to provide a theoretical reference for regulating the aroma quality of Rucheng Baimao black tea.