The effect of low temperature at night on the growth of young tea plant was examined using two years-old plants of several varieties cultivated in pots. The air temperature of thermostats was regulated as follows ;
by day at night
(9.30a.m.-4.30.P.m.)
30°C.
30
30
25
25
25
(4.30p.m.-8.30a.m.)
30°C
25
20
25
20
15
By varing the temperature from 30°C.to 25°C.(or 20°C.), the growth rate of shoots showed superior or similar to that at a constant temperature 30°C.
By varing the temperature from 25°C. to 20°C. (or 15°C.), however, the growth rate of shoots showed inferior to that at a constant temperature 25°C.

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The cold resistance of the Fl progenies crossed in 1960 was investigated.
The heritability value of cold resistance was 0.7098. It was recognized that the gene for cold resistance was dominant and gene constitutions on cold resistance were seemed to be concerned in polygenes.
The cold resistance of the Assam varieties was very weak so it was not easy to get any resistant Fl progeny even though resistant varieties were crossed with each other.
Genetic phenotypic and environmental correlations were not found between the cold resistance and the height of plant, the weight of plant by pruning (the vigor of plant) and the size of mature leaf.
As a results of these tests it would rather breed the varieties fit for a wide growing district in a warm climate than breed the resistant varieties in utilizing the Assam variety for crossing.

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1. By using clones of 170 hybrid. individuals, the correlation coefficients between combined main characters were calculated with parents and their clonal plants of different ages.
2. Owing to the data of the past examinations and the calculated values including both the environmental and genetic variance in this design, any problem with those tested years, especially, the climatic differences could not be recognized.
3. But some relations between such characters as above mentioned could be certained by this preliminary research, so further studies are expected.
4. Most of the clones, used in this research, were so young for general tea-life, that we have been going to have more times of replication with larger number of clone.
5. The results are generally summarized as follows.
a) Morphological characters of tea-leaf look to be fixed in the comparatively young ages. That is, they are thought to be high repeatable.
b) The relations between their characters of parent and its clonal plants were seen as like as the previous description, even though the clonal plants were very young.
c) With younger plants after setting, the correlation between the cold damage and the plant-age was significant on five percent level.
d) The correlations between paired characters were high with two kinds of shoot at a different stage, one of them had one bud and four leaves, and the other one bud and five leaves.
e) The correlation between two kinds of damage devided with the external appearance on leaf in cold and dry winter could hardly been found.
f) In connection with the winter damage, only the leaf-type showed a large coefficient of correlation between plant ages or between parent and its clonal plants, but not among the other characters.
g) The authors will have to study, in future, with more numerous combinations, on the genetic correlation and heritability excepted the environmental variance.
h) The correlation coefficients between the characters of young tea plant before setting are clearly different one another with the different combinations pollinated, and owing to taking care of the genic combination, linkage and so on the authors expect to test combining ability or to do selection by every combination.
i) On the correlation after setting, the rooting-ratio may be variable on account of transplanting. Then the authors must take charge of the advanced research in future.
j) From the technical point of view, the authors will need to use fifty individuals every other combination at least, as materials for such a calculation. And, further more, theoretically, the authors would want one hundred or two hundred individuals.
On this point, the authors intend to study on the other day, taking counsel with their staffs.

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Kôro (_??__??_ in Chinese) tea plant which named Thea sinensis L. var. macrophylla by P. F. SIEBOLD exsist in several places of Japan and were called To tya=Chinese tea or Niga tya =bitter tya.
C. P. STUART refered the plant to one of the four varieties of the tea plant and KITAMURA named the plant Camellia sinensis var. sinensis f. macrophylla (SIEB.) KITAMURA.
Author carried out the crossing and selfing tests using the Japanese so-called Kôro tea plant and other clones. As a result of above tests, it was cleared that the distinctive characters, that is, particularly large and undulating leaf etc. of this lant were controlled by a single recessive gene (k), and Yabukita, the famous variety for green tea in Japan was proved to be hetero plant fo the gene.
The Kôoro type plant rose in the openpollinated progenies of the k hetero clones (Yabukita, U4 and S24) at 0.6-5.4%.
Then, the natural self-fertilization of the tea clones was estimated at about 10% on an average condition.

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[in Japanese]

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1. The relation between the climatic conditions and the outbreak of the white scab (Sphaceloma theae KUROSAWA), and in this connection some ecological characters of the disease were investigated.
2. Inoculation experiments and field observations showed that the fungus could invade young twigs and the six leaves from the top of the growing shoot, but most serious invasion occurred in the second to third leaves.
3. The incubation period of the disease was 2-4 days under the suitable environmental conditions.
4. Conidia were produced more numerously on the tea extract agar at a temperature of 15-20°C. and in the dark than in the light of fluorescent lamp or sun.
5. It seemed that the young leaves became more susceptible to the disease when exposed to a low temperature of about 10°C. for 1 or 2 days before inoculation, but a high humidity prior to infection gave little effect on the susceptibility of tea leaves.
6. From the inoculation experiments and the field observations, the temperature range favourable to the outbreak of the disease was 15-20°C. (daily average), and the fungus might invade the host tissue when a high humidity continued for 10-odd hours.

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1. Soil sterilization was carried out using 3 fungicides in tea field where white root rot of tea was occurring.
Chloropicrin (applied 20 ml. per (50cm.)² of the field) showed an excellent controlling power of the disease, but other two organomercuric fungicides did not show any effectiveness.
2. Growth of mycelium from diseased tea roots was nearly inhibited when the roots were dipped in the solutions of two organomercuric fungicides for 10-30 minutes.
No inhibitory effect on the growth of mycelium was found when the fungicides were applied in the soil in which the roots were buried.
3. In fields and pots, the fungicides were applied in soil in which diseased tea roots were buried. The fungicidal effect on the fungus in diseased tea root was examined in two ways: one was the examination of the growth of myceliumfrom the treated tea roots and the other was inoculation test with the roots against tea seedlings.
In pot test, chloropicrin and "Dorokurô"ru" (chloropicrin 80%) inhibited the growth of mycelium from the diseased roots completely, but a slight disease was occurred only when applied with 4 ml. of "Dorokurôru" per pot (diam. 30 cm.).
In field test, no fungicides inhibited growth of mycelium completely, but the disease occurrence was very slight in chloropicrin treatment [applied 3 or 6 ml. per (50cm.)² of the field]
4. From the results of these control experiments, chloropicrin was found to be practically available for the control of white root rot of tea.
"Dorokuroru" was inferior in the fungicidal effect to that of chloropicrin.
Any controlling power of organo-mercuric fungicides was not expected in the practical use.

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The absorption of phosphates by the tea plant was examined with radioactive (32P) monocalcium phosphate, iron phosphate in pots filled with Makinohara plateau reddish yellow tea soil.
The results were summarized as follows:
1) In the 1st crop, radioactive phosphates were dressed 12 days before plucking tea leaves.
The percentage of dressed phosphorus content to total phosphorus content in new leaves of the 1st crop was lower than 10% in every type of phosphate.
2) These rates of three phosphate in new leaves and young stalks through the 1st, 2nd ane 3rd crop were as follows ; mono-calcium phosphate ?? iron phosphate>aluminum phosphate.
These rates of mono-calcium phosphate and iron phosphate plot in young leaves and stalks were 40-70%, and that of aluminum phosphate plot was 35% in the 2nd and 3rd crop.
3) These rates in young stalks were higher than that in young leaves of every plot.
4) The transformation of radioactive phosphate in pot soil 90 days after dressing was. investigated.
Fifty eight percent of dressed mono-calcium phosphate was transformed into aluminumbound phosphate and 19% of that into ironbound phosphate.
Thirty five percent of the iron phosphate was transformed into aluminum-bound phosphate and 30% of the aluminum phosphate was transformed into iron-bound phosphate.

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The comparison of the growth and chemical components of the tea plant which was cultured with nutrient solutions containing various concentrations of phosphate or potassium was investigated from 1961 to 1963 by sand culture method. The results obtained were summarized as follows.
1. The growth of the tea plant was increased with increasing the concentration of phosphate or potassium. But there was general tendency that the increasing rate of the growth in the 50p.p.m. plot was higher than that in the 100 p.p.m. plot, respectively.
2. Phosphate content in the tea plant increased according to the supply of phosphate, and potassium content increased according to the supply of potassium. Total nitrogen, CaO and MgO content increased according to the supply of phosphate. Furthermore total nitrogen and MgO content were increased according to the supply of potassium.
3. Tannin content of the tea leaves was decreased with supply of phosphate or potassium, but it was considered to be caused by the different maturity of the leaves.
4. Sugar and starch contents of the leaves increased with supply of phosphate. Reducing sugar content of the leaves increased, but sucrose content decreased in the without potassium plot. Reducing sugar and sucrose contents of the old leaves increased according to the supply of potassium.
5. Inorganic-P content of the leaves was highest, phytin-P content was lowest than each phosphate fraction, and it was not different between nuclein-P and phosphatid-P content. Inorganic-P content decreased in the without phosphate plot.
6. The absorption of phosphate or potassium by the tea plant was high in July, August, and September, respectively.

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Potassium supplying power of tea soils derived from volcanic ash soil, diluvial red-yellow and "Kuroboku" soil and tertiary yellow soil were examined by the extract method with N-nitric acid and 0.01 N-hydrochloric acid. Furthermore, potassium fixation power of those tea soils were examined by the VOLK'S method.
The results were summarized as follows:
1. Potassium supplying power of the four tea soils were pressumed as follows by the amounts of N-nitric acid soluble potassium of those tea soils, but that of diluvial "Kuroboku" soil did not show thee difinite tendency.
Tertiary yellow soil>diluvial red-yellow soil>volcanic ash soil.
Differences of potassium supplying power of soil between tea soil, cultivated soil and uncultivated soil were not abserved.
2. From the characteristic potassium release curve of soil leached with 0.01 N-hydrochloric acid, potential potassium supplying power of those tea soils were abserved.
Potential potassium supplying power of volcanic ash soil was the smallest and that of red-yellow and tertiary yellow soil was comparatively larger than the other soils. Furthermore, that of "Kuroboku" soil was larger than that of volcanic ash soil, but was presumed to be slightly smaller than that of red-yellow soil and tertiary yellow soil.
3. Potassium fixation power of those tea soils was determined. It was observed that potassium fixation power of volcanic ash soil was generally small compared to the other soil and potassium fixation power of soil was not different among the other soils except volcanic ash soil.

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The essential oils of the fresh and the cold-stored tea leaves were examined by gas liquid partition chromatography.
It was found that cis-βγ-bexenyl acetate and cis-βγ-hexenol which gave flavor of fresh young tea leaves decreased while some unknown carbonyl compounds increased during storage. It was thought that the change of these components in the essential oil influenced the off-flavor of tea made from stored tea leaves.
The increasing of the unknown carbonyl compounds had a negative correlation to the oxidative degradation of ascorbic acid in tea leaves. Therefore, it was thought that these carbonyl compounds were formed by the oxidation of the essential oil during storage.

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Two types of storage container for tea leaves were designed as shown in Fig. 1 and 2.
Plucked tea leaves of 60 kg./m². (thickness 65 cm.) and 35 kg./m². (thickness : 40 cm.) were stored in the containers for 5-9 days at a constant room temperature 2°C.
During the storage, the temperature of the charged tea leaves was maintained at about 5°C.
There was no significant deterioration in the qualities of green tea made from the stored leaves.

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