To improve tea varieties suitable for southwestern Japan, a tea breeding project has been carried out at the Tea Breeding Section, Tea Division, Miyazaki Agricultural Experiment Station. In April 1970, the station released the new variety "Unkai" suitable for Kamairicha, which was registered with M. A. F. as a superior variety.
"Unkai" was selected from the F₁ hybrids between "Takachiho" and "F₁ 9-4-48" which was an F₁ hybrid of MA 23 (the Assam var.) × MC 3 (the Caucasia var.). This variety was tested for local adaptability at several experimental locations in southern Kyushu and Tokai districts as a clone No. A 15 before it was registered. The results of the tests showed that the variety was excellent in growth, yield, coldresistance, disease-resistance, marketing quality and table quality. Therefore, it was adopted as a recommended variety in Kumamoto and Miyazaki prefectures.
The characteristics of this variety are as follows:
1. This variety, like "Yabukita", is a few days earlier than "Takachiho" in plucking time. On the other hand, the sprouting time is a few days later than that of "Takachiho" and "Yabukita".
2. This variety is an intermediate type with respect to shape of plant, and it shows vigorous growth and high yield from early stages to mature stages.
3. This variety has higher resistance than that of "Takachiho" and "Yabukita" to net blister blight and anthracnose, and it also has high resistance to winter injury in natural and artificial conditions.
4. The vegetative propagation of this variety is as easy as it is with " Takachiho " and " Yabukita " varieties using the usual cutting method.
5. This variety has superior marketing and table qualties equal to those of "Takachiho".
6. From the results of the experiments testing the local adaptability of " Unkai" variety in different environments, it is concluded that it is a suitable variety in south-western Japan.

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A new tea variety named "Kanayamidori" is a clone suitable for green tea. It was bred by the Breeding Laboratory of Tea Agronomy Division, Tea Research Station, and registered with M. A. F. as a superior variety in April, 1970.
"Kanayamidori" originated from the F₁ hybrid of S6 (the Shizuoka native variety) × "Yabukita" (the superior green tea variety). Both mature and young leaves of this variety are smaller in size than those of "Yabukita", slightly elliptic in shape, glossy, and dark green in colour.
"Kanayamidori" is a slightly late variety with a spreading growth habit and numerous shoots. The sprouting time of this variety is about eight days later, and the plucking time is about four days later than those of "Yabukita", respectively.
The superior characteristics of this variety are strong cold-resistance, vigorous growth, high yield, and fine quality. Its yield is much greater than that of "Yabukita", and its quality is as good as that of the latter. Cuttings of this variety root readily and show good growth after rooting.
"Kanayamidori" is adapted to the green tea areas of Tokai, Kinki and Kyushu regions, and also some hilly areas because of its tolerance to cold and its late plucking period.

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In the present paper, it was shown that the prediction of yield was carried out by means of multiple regression analysis between yield and characters of shoot using 21 clones for black tea.
In this analysis, dependent variable was yield (Y), and independent variables were number of flush shoots per unit area (X₁), weight of 100 plucked shoots (X₂), average length of flush shoot at plucking time (X₃), leaf number of flush shoot at plucking time (X₄), average length of plucked shoot (X₅), and width of row (X₆).
Fifteen multiple regression equations of yield were calculated in 1st, 2nd and 3rd plucking seasons, respectively. These equations included three to six independent variables. Both X₁ and X₆ were common to all equations, and the other variables were combined in all combinations.
Processing of the data was accomplished by a TOSBAC 3400 computer of the Computing Centre for Research in Agriculture, Forestry and Fishery.
The multiple regression equations including six characters were given as follows:
1st plucking season;
Y =-1792.5+2.36X₁+3.02X₂+19.79X₃+17.08X₄-20.27X₅+1.32X₆ R=0.902 2nd plucking season;
Y =-1239.6+0.75X₁-0.02X₂+21.96X₃+35.74X₄-7.87X₅+0.77X₆ R=0.946 3rd plucking season;
Y=-387.4+1.48X₁+3.48X₂+22.80X₃-39.40X₄-24.10X₅+0.49X₆ R=0.855
Squaring these correlation coefficients gives 81%, 89% and 73% as the percentage of the variability in yield accounted for by its association with the six characters.
It became clear that these multiple correlation coefficients were so high that the yield of each plucking season could be predicted accurately by these equations.
As the number of concerned independent variables in a equation diminished, the values of multiple correlation coefficients gradually diminished, but all multiple regression coefficients exceeded the 1% or 5% level of significance.
The multiple correlation coefficients including X₁, X₃ and X₆ were 0.868, 0.921 and 0.780 in each plucking season, respectively. There were only a little differences between the multiple correlation coefficient including three characters and that including six characters in each plucking season. Therefor, the multiple regression equation including X₁, X₃ and X₆ is also considered to be practically useful in predicting the yield.
From the values of standard partial regression coefficients, it may be concluded that the important characters to predict the yield in mature tea garden are number of flush shoots per unit area, average length of flush shoot at plucking time, and width of row. It seems to be necessary to find the young plant's characters which are closely related with these three characters for young plant testing on yield.

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Experiments were carried out to develop a labour-saving method of planting the tea cuttings by using vinyl film cover over the nursery bed.
In June the cuttings were grown without watering by covering the nursery bed closely with vinyl film in tunnel form for about 45 days after planting. The planted cuttings, however, had to be fully watered before the bed was covered with vinyl film.
The vinyl-covered beds were shaded from the sunlight by three layers of "Kanreisha (# 600)" (cheese cloth). This reduced the intensity of the light about 85 percent and gave good results.
Where possible, it was better to take cuttings with three or four leaves. Such cuttings rooted readily and developed rapidly.
In summer the optimum planting time of cuttings was considered to be late May after the first harvesting period. In autumn, however, it was early October. Being covered with vinyl film from autumn to the following April, the cuttings developed into good saplings. The cuttings also rooted readily in March by this method.
Using vinyl film cover, it was possible for us to propagate new tea varieties rapidly.
From this experiment, it was found that tea cuttings could be planted in every season of the year, and much time and trouble were saved by this vinyl film covering method.

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1. It has been said that the development of the mite resistibility may be due to the heavy applications of acaricides and insecticides in the field.
In this paper some results are reported of the continual use of Estox, O, O-Dimethyl s-(1-methyl-2-ethylsulfinyl) -ethyl phosphorothioate, to the Kanzawa spider mite (=Tea red spider mite), Tetranychus kanzawai KISHIDA, in the laboratory.
2. The susceptible mites to Estox turned to resistance by the five treatments to adult female mite every other generation with 0.005% emulsion of Estox, and their resistant level in LC₅₀ values reached about seventy times compared with the former population.
3. From the results of above mentioned, the author thought that the mite resistibility to Estox might be developed by the few times of spraying with Estox continuously and at high concentration.

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The absorption of ⁸⁶Rb in young tea plant was investigated using short term solution culture.
The results were summarized as follows:
1. It was observed in radio-autograph that a great deal of ⁸⁶Rb was absorbed in veins of a leaf.
2. The order of the amount of absorbed ⁸⁶Rb in each part of young tea plant was to the following effect, rootlet fibril>old trunk>young trunk>old leaf>new leaf.
3.According to the increase of potassium concentration (0, 2.5, 5.0, 10.0, and 20.0 me/l) in the constant solution of Rb concentration (Rb 5 me/l:3.0 μ Ci/l), the amount of absorbed ⁸⁶Rb in the new leaf, young trunk and old leaf was increased, but that in the rootlet was decreased.
4. Accordimg to the increase of magnesium concentration (0, 5.0, and 20.0 me/l) in the constant solution of Rb concentration (Rb, 5.0 me/l: 7.5μCi/l), the amount of absorbed ⁸⁶Rb in each part was increased, and the amount of absorbed ⁸⁶Rb in young and old leaf was less than that of rootlet and young trunk.

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The evaluation of NH₄-N and NO₃-N as nitrogen source on the tea plant which supplied in media containning 25, 50, 100 ppm. of nitrogen respectively was investigated from 1963 to 1964 by sand culture method. The results obtained were summarized as follows.
1. Generally, the tea plant supplied with NH₄-N showed better growth than that with NO₃-N. The growth of the tea plant increased according to the amount of nitrogen sources in the first year, but that decreased in high concentration next year.
2. Nitrogen content in the tea plant supplied with NH₄-N was higher than that with NO₃-N, and increased both according to the amount of nitrogen.
3. Potassium content of the tea plant cultured with NH₄-N showed lower than that with NO₃-N. Calcium content of the tea plant in NH₄-N plot decreased according to the amount of nitrogen. Magnecium content of the tea plant cultured with both nitrogen sources decreased according to the amount of nitrogen.
4. Polyphenol oxidase activity and catalase activity of the tea leaves cultured with NH₄-N showed higher than that with NO₃-N.
5. There was general tendency that assimilative power and respiratory activity of the tea leaves cultured with NH₄-N showed higher levels than that with NO₃-N.
6. Chlorophyll content of the tea leaves cultured with NH₄-N was more than that with NO₃-N.
7. Tannin content of the tea leaves cultured with NH₄-N showed higher than that with NO₃-N. And tannin content of the tea leaves increased according to the amount of NH₄-N but decreased by NO₃-N.

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The aroma recovery and retention methods of producing full-flavor of instant green tea were investigated on the laboratory scale.
The volatil components of raw tea were collected in three steps of low temperature traps by vacuum distillation. The -80°C fraction, to which 10-15% of lactose was added, was freeze-dried to retain the volatiles.
As the results of sensory tests, it was found that the flavor of instant tea became better by adding the collected volatiles to the product obtained by vacuum-concentration of the dilute aqueous tea extract, on the contrary, by freezedrying of the concentrated solution with the aid of semi-multiple-countercurrent extracting apparatus the flavor of instant tea could not be improved now.

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To develope a new use of tea, inhibitory effects of water-soluble components of tea on plant viruses were investigated in 1966-1968.
The aqueous solutions of them were injected into the soil around the base of the plants. The combinations of viruses and host plants were as follows :
TMV : Physalis alkekengi L. ; N. tobacum (Bright Yellow-4) ; Tomato ; N. glutinosa
CMV : N. tobacum (KY-57) ; vigna sinensis SAVI.
In experiments of systemic, infection by TMV, free catechins, catechin mixture and aqueous extract of tea seemed to be slightly inhibitory. Free catechins and catechin mixture were also a little effective for the inhibition of CMV Infectivity.
In local infections by TMV and CMV, it was observed that the number of lesions on the inoculated leaves of plants treated with tea catechins (free, ester and their mixture) and caffein was compared to less than the untreated ones.

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Inhibitory effects of four kinds of tea catechins on infection with plant virus, TMV and CMV, were investigated.
Nicotiana tabacunz (KY-57) was used as the infection plant with CMV, and tomato and N. glutinosa as the infection plant TMV. Each of four tea catechins was added in a concentration of 5 mg/ml. to the sap squeeced from the leaves of tobaco or cucumber infected systemically with the virus. The leaves of the plants were inoculated by rubbing with the mixed inoculum.
Inhibitory effects of the concentration of tea catechins. (-) ECg and (-) EGCg, on TMV multiplication, using N. glutinosa as the infection plant, were also investigated.
When each of four tea catechins was added to a concentration of 0.5% to 1 % gelatin solution, (-) EC and (-) EGC did not give the emulsion, but (-) ECg and (-) EGCg became immediately muddy to form some precipitates. The same results were obtained when virus inoculant of TMV and CMV were used instead of the gelation solution.
At 8-25 days after inoculation, symptoms of virus disease by CMV plus (-) EC or (-) EGC were observed in some cases and were not in the others. However, any symptom could not be observed even at 30 days after by CMV plus (-) ECg or (-) EGCg. These results indicated that such tea catechins as(-) ECg and (-) EGCg which seemed to combine readily with protein, had high inhibitory effects on plant virus.
In experiments of systemic infection and local lesion formation on the leaves of N. glutinosa by TMV plus tea catechins, inhibitory effects of (-) EC and (-) EGC could not be observed. and also any symptom was not observed in both systemic and local infection by TMV plus (-) ECg or (-) EGCg. Subsequently it was concluded that these two catechins were almost completely inhibitory against TMV multiplication. The number of local lesions on inoculated leaves were very much decreased in proportion to the concentration of (-) ECg and (-) EGCg in the inoculum and the formation of local lesion could not be observed at 0, 5% of them.
Thus, it was supposed that (-) ECg and (-) EGCg combined rapidly with plant virus protein, resulting in inhibition of virus multiplication or decreasing of local lesion formation.

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In order to study the discoloration of green tea during storage, we investigated the application of Dietrich's method, in which the conversion of chlorophyll to pheophytin was determined.
The formula described by Dietrich was as follows:
percent conversion= R_X-R₀/R₁₀₀-R₀×100
where, R₀: ratio of optical density (OD) readings 534 mμ/556 mμ for zero conversion
R₁₀₀: ratio of OD readings 534 mμ/556 mμ for 100% conversion
R_X: ratio of OD readings 534 mμ/556 mμ for the unknown
Using green tea, the following equation was obtained.
percent conversion= Rx-0.96/1.29 × 100
Yet, as this equation may vary slightly with some conditions of analysis used, it seems to have need for each analyst to set up his own equation with each instrument.
The procedure and calculation by this method in green tea are; add 40 ml. of 90% acetone to 0.3g. of powdered green tea in a 50ml. flask and extract pigments allowing to stand for 3 to 5 hours. Then, read the OD at 534 mμ and 556 mμ of the supernatant of the acetone extract and calculate percentage conversion by the above equation.
Then, it was recognized that the percentage conversion in this method agreed approximately with that calculated from pigment contents which were estimated in the method of TAN et al.

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Mn, Cu, Na, K, Br and Zn in tea plant were determined by non-destructive activation analy-sis, using Ge (Li) gamma ray spectrometer.
The levels of each elemental content showed the characteristic differences between part of tea shoot or tea vegetative cutting and tea root collected at the interval of two or four months.
Some parts of Mn and Cu were recognized in chloroplast, mitochondria and soluble protein in the supernatant after centrifuging at 12, 000 x g, and the most parts of Na and K appeared in non-protein fraction of the supernatant.
As the characteristics of the elemental contents in Japanese tea, it was indicated that the levels of the Na content in green tea and the Cu content in black tea were higher than of the imported teas.

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A fundamental approach to make a control equipment for a cutter of the tea plucker of a selfpropelled tractor type was firstly examined by manual operation of the cutter.
Coupling a cutter with an oil pressure type of lift arm of tractor was used for vertical adjustment, while a vibration of top link was used for horizontal adjustment by link motion.
The plucking job was easy in 20-30cm./sec. of a tractor's velocity and 7 -10cm./sec. of the terminal velocity of this equipment.
A sufficient accuracy was obtained in plucking of uniformly grown shoots, whereas it was not satisfactory in plucking of poor grown shoots.

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A manual control of cutting motion of the tea leaf plucker was reported previously. An automatic mechanization of plucking was examined to improve accuracy, efficiency, and labour consumption of plucking.
An automatic controller by oil pressure through jet pipe system was mounted on the tea plucker and it was used for vertical and horizontal adjustment.
The detection method of edge position was applied to the detection of displacement by introducing an air-pressure signal to the controller.
A sufficient plucking accuary was confirmed in a practice using the automatic controller.

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An on-off control system of cutting motion of the tea leaf plucker was examined in laboratory level using oil pressure as supplementary power.
An automatic controller was consisted of the detecting plate, microswitch, solenoidal valve, and hydraulic cylinder, etc.
Displacement of the controller was given by a displacement stand and a belt conveyor. In the testing set, a movement of the control element corresponding to displacement of the detecting plate was recorded by an electromagnetic oscillograph.
The follow-up of the control element corresponding to upward displacement of the detecting plate became worse as the distance between pushbuttons decreased, whereas that corresponding to downward displacement was satisfactory.
Though a displacement angle or conveyor speed varied, the follow-up of the control element was not affected significantly by approaching of piston speed to theoretical speed.
When the speed-up ratio of a piston motion became over 15% of theoretical speed, a sudden hunting was observed.

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