Bioscience Evidence 2026, Vol.16, No.4, 235-248 http://bioscipublisher.com/index.php/be 242 to two weeks earlier than most other green tea cultivars. For this reason, Wuniuzao is widely known as the earliest spring tea in Zhejiang. For the tea industry, early harvesting is valuable not only because it advances the harvest date but also because it allows producers to enter the premium spring tea market ahead of competitors. In recent years, Yongjia County has continuously expanded Wuniuzao cultivation and developed an integrated industry combining tea production, processing, branding, and tea tourism. Today, Wuniuzao has become an important specialty crop that contributes to local agricultural development and farmers' income. The early sprouting habit of Wuniuzao is mainly determined by its genetic characteristics. In comparative trials of early-maturing, high-quality green tea cultivars conducted by the Tea Research Institute of the Chinese Academy of Agricultural Sciences, Wuniuzao was evaluated together with cultivars such as Zhongcha 108 and Longjing 43. The results showed that Wuniuzao consistently initiated bud growth earlier than the other cultivars, allowing it to reach the harvesting stage first during the spring production season in Zhejiang. As a result, it has become one of the most important sources of fresh leaves for premium early spring green tea (Yang et al., 2003). The high quality of Wuniuzao is also closely related to the environmental conditions during early spring. Because bud break occurs very early, young shoots develop under relatively low temperatures and weak light conditions. These conditions slow shoot growth, favor the accumulation of umami-related compounds, and reduce the formation of bitter and astringent substances. Consequently, processed green tea has a distinct tender aroma, a fresh taste, and a clear liquor. As temperatures continue to increase later in the season, tea plants enter a period of rapid growth, and bitter compounds gradually accumulate in the leaves. This explains why Wuniuzao can be harvested throughout the growing season but why its highest-value products are almost always produced from the earliest spring harvest. 5 Practical Recommendations for Tea Growers and Agricultural Extension Workers 5.1 Optimal harvesting time Tea quality first depends on whether the leaves are harvested within the proper harvesting window, rather than simply pursuing the earliest possible harvest or delaying harvest to obtain a higher yield. In spring, low temperatures slow shoot growth and keep the leaves tender, making this the best period for producing premium green tea. As temperatures rise, buds and leaves grow rapidly and gradually mature. Compounds related to freshness begin to decline, while bitter and astringent substances increase. Therefore, even when the leaves are still classified as spring tea, harvesting too late can reduce the final product quality. For premium green teas in Zhejiang, such as Longjing tea and Anji White Tea, harvesting should be arranged according to the actual development of buds and leaves. One bud with one leaf or one bud with two leaves should be used as the main harvesting standard. Growers should avoid delaying harvest simply to increase yield, as this may result in missing the best quality period. A reasonable harvesting frequency is also important. Aaqil et al. (2023) found that shortening the harvesting interval appropriately not only increased fresh leaf yield but also maintained a higher proportion of tender buds and one-bud-two-leaf shoots. In contrast, excessively long harvesting intervals increased the proportion of coarse and mature leaves and reduced processing quality (Figure 3). Benti et al. (2023) pointed out that tea bud growth is jointly affected by temperature and rainfall. Harvesting plans should therefore be adjusted according to local phenological changes rather than being organized according to fixed calendar dates. At the farm level, harvesting dates should be adjusted promptly according to changes in spring temperature. Labor, transportation, and processing capacity should also be arranged in advance to ensure that fresh leaves are harvested and processed on the same day, thereby maintaining their quality as much as possible. 5.2 How to improve spring tea quality The key to improving spring tea quality is not simply to harvest as early as possible, but to maintain leaf tenderness during the proper harvesting period and make full use of the quality advantages created by low spring temperatures. Spring tea usually contains relatively high levels of amino acids and has a good aroma foundation. Therefore, tender shoots should be harvested at the correct time, and overly long harvesting intervals should be avoided. Once the leaves become mature, the freshness and tender aroma of the tea liquor decline noticeably, even
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