The management technique of tea trees in order to take the stable yield of the first crop in the next year was examined by influences of plucking or not of the third crop, shapes of autumn shoots, and the vitality of shoot.
The yield of the first crop in the next year in a field of the medium pruning differed in plucking or not of the third crop. Taking the above yield of the first crop in the next year, it seemed proper that plucking of the third crop was carried out in 3 years, non plucking of the third crop had better do 4-5 years after, and non plucking of the third crop 6 years after, furthermore. On the other hand, the first crop in the next year was lots of yield by plucking of the third crop in a field which has undergone light and deep trimmings after the second crop.
In case of immediately after the medium pruning, shape of autumn shoots was large, and regenerated new shoots of the first crop were many after pruning of new shoots. However, it would rather be treated in a medium pruning field passed several years by non plucking of the third crop.
It is presumed that the vitality of shoot will become weak year by year after the previous medium pruning. Therefore, it is desirable to pluck or not of the third crop by the interval from the previous mediuma pruning.

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Control effect of saponins refined from tea seed against lepidopterous larvae and spider mites were tested in the laboratory. They do not effect on the survival of larvae of Adoxophyes honmai YASUDA and Pryeria sinica (MOORE). They suppress the population increase of two species of spider mites, Tetranychus urticae KOCH and T. kanzawai KISHIDA. When they are sprayed in high concentration (100-times dilution), they strongly suppress the oviposition of adult mites and have acaricidal action against larvae and nymph, but no acaricidal action against adult mites. The effect is stronger against T. kanzawai. than T. urticae.

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Qualities and properties of commercially available green teas were investigated on the basis of chlrophyll and its related derivatives contents.
(1)Pigments contents among the different types of tea
The Ooishita-cha, Maccha and Gyokuro, contained more chlorophyll (Chl) (a+a') and (b + b'), on the contrary, less pheophytin (Phy) (a + a') and (b + b') than Fukamushi sencha. Furthermore, the changing rate of Chl into Phy and the ratio of Chl (b + b') to Chl (a+ a') in Ooishita-cha were less than Fukamushi sencha. Sencha was in the middle between Ooishita-cha and Fukamushi sencha.
(2)Pigments contents among the different grades of tea
(a)In Maccha, Gyokuro and Sencha, the higher grades of tea contained more Chl (a+a') and (b + b'). Fukamushi sencha gave the opposite results. However, there were not signifi-cant differences in the contents among the different grades of tea. (b) In all types of tea, the higher grades of tea contained less Phy (a+a') and (b+b'), and the differences in the contents were markedly clear. (c) In all types of tea except for Fukamushi sencha, the higher grades of tea gave the less changing rate of Chl into Phy, and the differences in changing rate were markedly clear in Gyokuro and Sencha. (d) In all, types of tea except for Fukamushi sencha, the higher grades of tea gave the less Chl (b+b')/Chl(a+a') ratio. Especially, the differences were clear in Sencha.
The contents of Phy (a + a') and (b + b'), the changing rate of Chl into Phy, and the Chl (b+b')/Chl(a+a') ratio might be used as an indicator for the estimation of tea quality in Maccha, Gyokuro and Sencha. For the more presice estimation, it is effective to use these informations together. It is difficult for Fukamushi sencha to estimate its quality on the basis of the only pigments contents.

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'Ryofu' was developed from 'Houryoku' x 'Yabukita' in 1972 and released in 1997. The growth of nursery plants is very good. The growth after planting is fairly vigorous. The shape of plant is slightly erect. 'Ryofu' is resistant both to cold in midwinter and to bark splitting injury. It is fairly resistant to tea anthracnose (Gloeosporium theae-sinensis). 'Ryofu' is an slightly late cultivar, and the flushing date of the first crop is 4 days later than in 'Yabukita'. The color of new shoot is yellowish green. Yield of this cultivar is higher than that of leading cultivar 'Yabukita'. The color of processed tea is brightly green. The color of liquor is clear golden yellow. The taste of the processed tea is a little astringent, but strong body and brisk.

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Numerical taxonomy was conducted to discuss the intraspecific classification of tea plant based on the variations of floral morphology. Experimental materials were main clonal cultivars (Experiment 1) and stock populations (Experiment 2) in Makurazaki; NIVOT, belonging to geographical sources of tea species.
Experiment 1: The 103 clonal cultivars selected from the different sources; Japan(numbers of Cv; 44), China (14), Assam (14), Assam hybrid (20) and Others (11) were investigated for the diversity of the 13 flower characters, such as flower size, number of petals, traits of pistil and stamen, and hairiness of ovary. Principal component analysis (PCA) and discriminant analysis were performed using the data of chosen 11 characters.
Large variation was shown among the cultivars for 6 characters. They are relative length of pistil to stamen (character code no. 4), splitting point of the style (8), constriction of the splitting arms (9), hairiness of the ovary (10) and number of stamens (11). Typical Japanese originated cultivars were with the same length of pistil as of stamen (Code M; according TAKEDA et al. 1980) or shorter one (Code S). Almost of all the Chinese originated cultivars had a longer pistil than stamen (Code L) with distinct constriction of splitting arms. Many Assam group cultivars generally had a longer pistil (L), but some cultivars were the same length of pistil and stamen (M). The cultivars with glabrous or less hairy ovary were observed in Assam plants.
The first component of PCA was loaded with primarily morphological characters of pistil such as relative length of pistil to stamen and constriction of style arm. Principal component score 2 mainly correspond to the characteristics of flower size and number of petals. The first three cumulative contributions accounted for a total 62% of the variation in the traits measured. In the discriminant analysis, taxonomic distance estimates based on morphological flower characters were significantly different between each group. This showed that the Japan, China and Assam groups of cultivars were clearly classified. Flower characteristics of the Assam hybrids resembled the China and Assam cultivars so their taxonomic distances were generally narrow.
Experiment 2: The 1, 356 accessions of 42 populations which belongs to the source of Japan (number of populations ;17), China (10), Assam (11) and others(4) were examined for the 6 characters of the flower morphology to clear the variations within and between groups of tea plant populations.
Distinct differences among the groups in the pistil characters, such as relative length of pistil to stamen and constriction of style arm were detected as the same results of Exp. 1 . The plants having long pistil with distinct constriction were found more frequently in the China and in the Assam populations than in the Japan ones. Glabrous or less hairy ovary was sometimes found in Assam accessions, but none in Japanese plants. It was recognized that the diversity of all characteristics within the Assam group was wider than in the Chinese or in the Japanese plants, and a 'cline'of the character diversity of floral morphology from the Assam to the China and to the Japan. It suggests that the origin of the tea plant is near and surrounding the area where the Assam groups of plants are distributed in the Southwest districts of China.
Principal component analysis and cluster analysis were carried for the 6 flower characters of 42 populations of 5 groups in Exp. 2. The 1st component score of PCA was loaded with the traits of the style which was like as Exp.1. Contribution of the 1st component mostly related to the characters, i.e. relative length of pistil to stamen and constriction of style had a score as high as 50%. The 2nd component mainly related to the flower size and hairiness of ovary, and their contribution ratio was 22%.

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We described an improved method for the simultaneous analysis of major tea components, four major catechins, caffeine, theanine and ascorbic acid using capillary electrophoresis. The composition of the electrolyte was 50 mM of boric acid, 10 mM of sodium phosphate (dibasic), 50 mM of sodium dodecylsulfate and 10% of methanol, and the pH was adjusted to 8.2. The temperature of the capillary tube was maintained at 20°C, and the potential applied was 25 kV. It needed less than 20 min to determine catechins, caffeine, theanine and ascorbic acid using this improved method. The analytical results of both tea infusions and the extracts of tea leaves using this method agreed with those using authentic methods, except those of ascorbic acid in tea leaves.

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A new cultivar‘Sakimidori’for green tea developed from a seedling derived from the cross of‘F₁ NN27’בME52’at the Miyazaki Agricultural Experiment Station in 1979.
A Clone was selected by individual selection in 1984. It was subsequently evaluated under the designation of ‘Miyazaki No.15’for local adaptability at the fifteen tea experiment stations and for Bark splitting injury and Blister blight at two other experimental station from 1988 to 1996.
'Sakimidori'has been registered under the name of 'Norin No.47 tea' by the Ministry of Agriculture, Forestry and Fishueries and released in 1996.
The characteristics of this new cultivar are as follows;
1) The shape of the plant is intermediate type and the growth is fairly vigorous.
The mature leaf is elliptic, slightly large size and light green in color. The immature leaf is bright fresh green color.
2) An slightly early budding cultivar, both the flushing and the plucking times of the 1st crop occured earlier by two to three days than in 'Yabukita'.
3) The annual green leef yield is higher than that of 'Yabukita'. The plucked new shoots is bud weight type.
4) Fairly resistant to cold in midwinter and to bark splitting injury in earlywinter.
It is middle susceptible to tea anthrancnose (Colletotrichum theae-sinensis) and tea blister blight (Exobasidium vexans). And it is slightly susceptible to tea gray blight (Pestalotiopsis longiseta).
5) Quality of the processed tea is very good because the color of made tea is bright green, aroma is fresh and taste is very mild.
Each content of nitrogen, aminoacid in the processed tea of this cultivar is higher, and the catechin content is lower than those of 'Yabukita'.

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A new method to determine sodium ion and ammonium ion using capillary electrophoresis was developed. The concentrations of these ions in tea extracts were measured by this method and the results agreed with those measured by ion chromatography.

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