A new medium budding green tea cultivar (‘Sayamaakari’) with improved color has been bred at the Saitama Tea Research Institute. ‘Sayamaakari’ was selected from seedlings crossed between tea line 60F₁-148 and tea cultivar ‘Sayamakaori’ in 1981. The new cultivar’s optimum plucking time, yield, cold resistance, etc., were tested from 2012, with these efforts culminating in the registration of the cultivar under the name ‘Sayamaakari’ in 2017.

The shape of the cultivar is semi-erect, and its growth is slightly vigorous. The plucking time of the first crop of the cultivar is the same as that of ‘Sayamakaori’, which is one day earlier than that of ‘Yabukita’. The yield of the first and second crops of ‘Sayamaakari’ is more than that of ‘Sayamakaori'. ‘Sayamaakari’ demonstrates resistance to cold damage and mulberry scale. However, it has a weak resistance to anthracnose. ‘Sayamaakari’ has an umami and astringent taste, similar to that of ‘Sayamakaori’, but its color is fresh green, whereas that of ‘Sayamakaori’ is black. The unrefined tea of ‘Sayamaakari’ has a higher proportion of stem tea than ‘Sayamakaori’.

We examined the practicality of pest control systems for organic tea cultivation using pruning and materials that can be used in JAS organic certification and examined the pest control effects of pruning after plucking of first and second flush in this study. The pest control systems using pruning and materials that can be used in JAS organic certification suppressed the damage of Adoxophyes honmai Yasuda and Caloptilia theivora Walsingham. Pruning after plucking of first flush was effective in suppressing the damage of Empoasca onukii Matsuda and Caloptilia theivora Walsingham in the second flush, and pruning after plucking of the second flush was effective in suppressing damage to Aleurocanthus camelliae Kanmiya & Kasai in August. The first flush yield in the following year was not affected by pruning after plucking of first flush but was decreased by pruning after plucking of second flush, compared to that under conditions of no pruning with no pest control. The second flush yield in 'Fukumidori' increased by pruning after plucking of first flush in 2019 study, but the growth of the second flush was inferior due to pruning after plucking of the first flush in 'Okuyutaka' in a 2020 study. These suggest that pruning after plucking of the first flush may affect the yield of various varieties differently.

This study aimed to compare the component elution rates in cold infusions of two types of green tea, namely Sencha and pan fired tea, those had been produced from the same fresh leaves. Findings revealed that the theanine elution rates in pan fired tea were almost the same as those in Sencha. The caffeine elution rates six hours after the start of the cold-brewing process were lower in pan fired tea than in Sencha. Furthermore, the major catechins, that is, epigallocatechin (EGC) and epigallocatechin gallate (EGCG), had substantially lower elution rates in pan fired tea compared to Sencha under most brewing conditions while the concentration ratio of EGC to EGCG in pan fired tea was similar to that in Sencha. Consequently, it is thought that the elution rates of the components of pan fired tea are lower than those of Sencha even with cold water. However, the elution rates of pan fired tea can be increased to the same levels as those in Sencha by extending the brewing time and reducing the weight ratio of water to the tea leaves.

At the Kagoshima Prefecture Tea Market, the appearance (AP) and liquor color (LC) of teas being bid are photographed with a digital camera for the purpose of improving the tea quality, and the prices and numerical values obtained from texture and chromaticity analysis of the images are feedbacked to each farmer via smartphone. In this study, we report a practice of quality management in the local tea production using these Tea Market Smart-Information (TMS) . Principal component analysis using tea image analysis data made it possible to visualize the tea characteristics of producers in local area. The prices were greatly affected by the varieties and bidding dates, but were also affected by the color phase of LC and particle size of AP. Based on the control chart, the color phase values of LC tended to decrease when tea was manufactured during continuous rainfall periods. In addition, the annual variation in color phase of LC was affected by weather factors such as humidity, minimum temperature, and amount of solar radiation, although it largely depended on the varieties and tea factories. The newly introduced covering material to improve the LC was found to increase chlorophyll content and reduce wind damage of tea shoot. These data indicate the use of TMS greatly contributes to the visualization and quality control of the tea characteristics of producers.