Molecular Plant Breeding 2025, Vol.16, No.4, 221-230 http://genbreedpublisher.com/index.php/mpb 226 appropriate irrigation frequency, it is still possible to improve the quality of tea while minimizing yield loss. Achieve a balance between the two. 7.2 Impacts on labor, inputs, and sustainability Shading combined with scientific irrigation can also mitigate the impact of extreme weather on tea gardens. For example, it can reduce the incidence of pests and diseases, decrease the usage of pesticides and chemical fertilizers, thereby helping tea farmers save costs (Sun et al., 2020). Shading can also reduce the damage to tea plants caused by high temperatures in summer, extend the picking time, improve the efficiency of tea picking, and better arrange manpower (Zhang et al., 2022; Ge et al., 2024). Meanwhile, shading combined with reasonable irrigation can also make the water in the soil be utilized more fully, avoid waste, and enhance the sustainability of the tea garden ecology. 7.3 Implications for summer tea production in subtropical regions In subtropical regions, high temperatures, strong sunlight and drought often occur in summer, which have a significant impact on the growth of tea plants and the quality of summer tea. The coordinated management of shading and irrigation frequency provides a feasible method for growing summer tea well in this area. By reasonably adjusting the shading intensity and irrigation arrangement, not only can the contents of amino acids and chlorophyll in summer tea be increased, making the flavor and appearance better, but also it can help tea plants alleviate high-temperature stress, improve stress resistance, and allow buds and leaves to continue to grow (Sun et al., 2020). This is of great value for enhancing the market performance and economic benefits of subtropical summer tea. 8 Case Study: Field Evaluation in Zhejiang Tea Plantations 8.1 Experimental design: light-shading nets ×irrigation regimes In some typical tea gardens in Zhejiang Province, researchers conducted field experiments to test the combined effects of different shading methods and irrigation frequencies. Shading treatment includes no shading, single-layer shading and double-layer shading. For example, double-layer shading nets are set 50 centimeters above the canopy layer of tea plants to simulate different light intensity and light quality conditions (Zhang et al., 2022; Shu et al., 2024). The irrigation frequency was set as high frequency (daily irrigation), medium frequency (once every three days), and low frequency (once a week) in combination with the local summer rainfall and evaporation conditions, with the aim of creating a distinct moisture gradient in the soil (Ge et al., 2024). 8.2 Growth and quality indices under different treatment combinations The experimental results show that shading treatment can significantly improve the growth environment of tea plants, making the canopy temperature lower and the soil moisture more stable, thereby helping the buds and leaves grow more tender and better (Zhang et al., 2022). When using double-layer shading nets, the contents of umami and sweet amino acids in tea plant leaves increased significantly, while the content of tea polyphenols decreased. The ratio of amino acids to polyphenols increased, resulting in better overall quality of tea (Li et al., 2020). Shading can also promote the accumulation of chlorophyll and caffeine, and reduce bitter components such as catechins and lignin (Teng et al., 2020; Shu et al., 2024). The study also found that moderate shading, such as 80% shading for 12 consecutive days, can be used to produce first-grade matcha raw materials (Hu et al., 2024). After the irrigation frequency is increased, the soil moisture can be retained better, which can reduce the stress of tea plants in high-temperature weather and promote the growth rate of buds and leaves and the accumulation of inclusions together with shading. 8.3 Farmer perceptions and adoption potential Through field visits, it was found that many tea farmers recognized that shading and reasonable irrigation were helpful for improving the quality of summer tea, especially in years with dry and hot weather (Ge et al., 2024). The use of shading measures such as shading nets or tree shade can not only improve the flavor of tea, but also reduce pests and diseases and increase the diversity of microorganisms in the soil. Both ecological and economic benefits are good (Zou et al., 2022; Que and Zhao, 2024). Although some farmers are worried that shading will affect the yield, it is still possible to achieve both yield and quality by adjusting the shading intensity and
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