“Fukumidori” is a new clonal cultivar suitable for green tea.
It was bred at Saitama Prefectural Tea Experiment Station, and was registered in the Ministry of Agriculture, Forestry and Fisheries as a superior cultivar, “Cha Norin No.36”, in June 1986. “Fukumidori” was selected from the hybrids between “Yabukita” and “23F₁-107” (“Sayamamidori” × “Yabukita”).
Its pedigree is illustrated as follows.
Its vegetative propagation is very easy because of its good rooting ability. And it shows vigorous growth and consistently high yielding from a young plant.
As to the cold hardiness in winter, it is very hardy and more resistant than “Yabukita” (the leading cultivar in Japan).
Its bud opening time is medium and the plucking time of it is about one day later than that of “Yabukita”.
Its cup quality of the cultivar is very excellent, particularly in color of liquor and taste of the first crop.
Therefore, “Fukumidori” is adapted to the northern areas of green tea production in Japan, such as Saitama and Ibaragi prefectures.

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In the variety trial field of Saitama Prefectural Tea Experiment Station, cold resistance of main 32 cultivars of tea was investigated in every winter from 1974 to 1984. The subjects of investigation were cold injury ("Akagare") and winter desiccation injury ("Aogare"). From field observations made at the beginning of every March, the degree of injuries was graded from 1 (the slightest) to 9 (the greatest).
The results obtained in this study are summarized as follows.
1. There were significant differences in the degree of injuries between both years and cultivars.
2. The degree of cold injury ranged from 2.3 to 6.3, which was slight in 1979-1980, and great in 1981-1982. It was also found that injury oc-cured irrespective of age of plant during from 4 years to 14 years.
3. The degree of winter desiccation injury ranged from 1.0 to 6.4, which did not occcur every winter. There was a general tendency for younger trees to be highly susceptible to be injury:injuries on trees age more than 8 years were generally very slight except for a year with an unusually cold winter as experienced in 1984.
4. Those years when the degree of cold injury was moderate (average 4.0-5.0) and which showed high variability between cultivars (0.3-0.4), were suitable for "test years". And those years the degree of injury is abnormally high or low, were not suitable for "test years".
5. Those years when the degree of winter desiccation injury was moderate (average 3.0-4.0) and which showed high variability between cultivars (0.6-0.8), were suitable for "test years". It is important to roticc that the resistance winter desiccation injury should be made during younger age of trees.
6. For the cold injury, high negative correlation was found between the degree of injury and the accumulative temperature in the winter-time except for those rare years when the injury occurs unusually high. This suggests that coldness is responsible for the occurence of cold injury.
7. For the winter desiccation injury, high correlation was found between the degree of injury and a combination of low temperature of surface soil and the number of rainless days in the winter-time.
8. On the basis of data obtained in "test years", 32 cultivars were classified by their resistance against injuries, into 5 groups for cold injury, and into 6 groups for winter desiccation injury.
9. It was found that both resistancee were positively correlated with each other.
10. The cold injury was not significantly correlated with the first-croping yield except for the extraordinary cold winter of 1981. For the desiccation injury, however, negative high correlation was found in most years.

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The influences of plucking and skiffing system were discussed on the yield. The experimental plots were established on the combination of following three factors consisting of two or three levels.
Factors
1. Annual frequency of plucking:
1) three times, 2) four times.
2. Time of skiffing :
1) autumn, 2) both autumn and spring, 3) spring.
3. Severity of skiffing 1 cm (severest), 3 cm, 5 cm (lightest) above the last plucking level.
The treatments were applied first for 8-year old tea field and thereafter annually repeated. The yield and the characteristics of new shoots were investigated from 1976 to 1980.
1. The differences in the first crop among the treatments were considerably great in the Hon-cha plus Kariban yield but relatively small in the Hon-cha yield only.
2. When followed by 1 cm high skiffing, the three-time plucking almost equaled the four-time plucking in the Hon-cha yield in the first crop. When followed by 3cm high skiffing, however, the three-time plucking was superior to the four-time plucking in the Hon-cha yield in the first crop. When followed by the autumn skiffing, the three-time plucking was almost equivalent to the four-time plucking in the yield of the second and third crop. When followed by the spring skiffing, however, the three-time plucking was slightly higher than the four-time plucking in the yield of the second and third crop.
3. The spring skiffing was inferior to the autumn skiffing in the Hon-cha yield of the first crop but in the total yield including the Kariban of the first crop, hardly different from the autumn skiffing.
4. When the three-time plucking and the autumn skiffing were combined, the 3cm high skiffing showed the maximum yield in the Hon-cha of the first crop. When the three-time plucking and the spring skiffing were linked. the lighter the severity of skiffing was, the higher the Hon-cha yield of the first crop became. When the four-time plucking was applied, 1 cm high skiffing was superior to 3cm high skiffing in the Hon-cha yield of the first crop. For the yield of the first crop including the Kariban, and of the second and third crop, the lighter the severity of skiffing was, the higher the yield became.
5. In the first crop, the more the frequency of plucking was and the severer the severity of skiffing was, the more the number of the new shoots became. The autumn skiffing was more than the spring skiffing in the number of new shoots. In the second crop too, effects of the each factor on the number of new shoots were almost similar to the first crop. In the third crop, effects of the fac-tors of plucking frequency and skiffing time on the number of the new shoots became negative and the severest skiffing produced the minimum number of the new shoots.
6. In the first crop, the more the plucking frequency was, the lighter the weight of one-hundred new shoots was. The autumn skiffing and the sever skiffing were smaller than the spring skiffing and the light skiffing in the weight of one-hundred new shoots of the first crop, respectively. In the second crop too, the factors affected similally to the first crop on the weight of one-hundred new shoots. The effects of each factor on the weight of one-hundred new shoots were recognized similally in the second crop, too, but the effect of the plucking frequency reduced. In the third crop. effects of the factors on the weight of one-hundred new shoots became smaller and especially, the effects of the severity of skiffing on the weight of one-hundred new shoots showed adverse tendency to the first crop.
7. The maximum difference in the plucking time among the treatments was 6-10 days in the first crop season.
8. The severity of skiffing influenced most greatly on the earliness of the plucking time. When the autumn skiffing was, applied the severer the severity of skiffing was, the earlier the plucking time became and thereby, the plucking time advanced 3-4 days in maximum.

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In the paper, the influences of plucking and skiffing system were discussed on the tea quality and the contents of chemical components of the first crop. The experiment was conducted with the same constitution and procedure as the last paper. The tea quality, and the contents of tannin, nitrogen and amino acids were investigated from 1976 to 1980.
1. The plucking frequency and skiffing time hardly affected on the contents of nitrogen and tannin. The sever skiffing was lower in the nitrogen content but slightly higher in the tannin content than the light skiffing.
2. The difference in the amino acid content among the treatments was considerably great. The four-time plucking and the spring skiffing were somewhat higher in the content than the three-time plucking and the autumn skiffing, respectively. Especially, the difference in the content due to skiffing time was great when followed by the sever skiffing. The sever skiffing was higher in the content than the light skiffing.
3. Treatments that restrained and uniformed the growth of new shoots improved the appearance of tea.
4. The decrease in the plucking frequency, and earlier or severer skiffing improved the quality of liquor.
5. Annual repetition of severe autumn skiffing after the third crop was considered to result in a deterioration in the amino acids content and the quality of liquor.

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Skiffing, a cultural treatment, seems to have an important role not only in the control of height, form, growth and development of tea plant, but also in the nutrients supply and the humic accumulation to the soil.
The processes of decomposition and nutrients disappearance in the leaves and branches of tea plants obtained after skiffing were investigated by litter-bag method in a tea field.
In the case of deep skiffing, dry weights of skiffing materials (cut leaves branches) were 3.7 t/ha for leaves and 7.5t/ha for branches.
The amounts of nutrients including deep skiffing materials were N205kg, P25kg, K102kg, Ca63kg and Mg 15kg/ha.
The dry weight of leaves decreased rapidly 2 months after skiffing and subsequently decreased slowly. The dry weight of branches decreased slowly throughout the experimental period. Weights of deep skiffing materials remained after 12 months were 41% of intial value for leaves and 80% for branches.
There was the difference of the changes of the nutrients disappearance in skiffed leaves among the elements. K was easyly disappeared, N and P were a little rapidly disappeared, however, Ca, Mg and Al were disappeared slowly.
Decomposition of leaves was faster than that of branches. Dry weight and the amounts of N, P, and K of cut leaves decreased less than 50% after 2 months.
Therefore, it was suggested that the nutrients contained in cut leaves were returned to the soil within a short time-period.

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Enzymatic activities of triphenol oxidation as pyrogallol, phlorogulusinol and ethyl gallate were investigated using acetone powder preparated from old leaves and roots of tea plants cultivar Yabukita. And the effect of addition of Mn²⁺ and steaming process on the oxidation activities of par-tially purified PhO were investigated.
1. In old leaves, the enzymatic activities of triphenol oxidation were as ; Phl>Pyr>EG>GaA. In roots, that were as ; Pyr>Phl=EG>GaA.
2. EG was auto oxidation by Mn²⁺, and the activities were increased by acetone powder. The oxidation activities of PhO and PyO were increased a little by Mn²⁺. The activities of PhO were decreased by KCN and DDTC-Na.
3. By heating acetone powder, the relative activities of PyO, PhO and the enzyamtic oxidation of EG were reduced to 88%, 27% and 20% respectively.
4. By addition of Mn²⁺, the oxidation activities of partially purified PhO showed 6.93% increase. By steaming for 55 sec., the activities were reduced to 19.4%, but by addition of Mn²⁺ that were reduced to 33.0%.

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The relation between the character and the passing time of tea leaves in a steaming machine was examined.
The correlation between the passing time (Y) and the drum angle (X) could be described by Y=a e^bX. Then, the expressions were as follows.
(1) The 1st crop: Y=70.91e^-0.136X
Where, Y; the passing time of tea leaves in second.
X; the drum angle in degree.
(2) The 2nd and 3rd crops: Y=68.10e^-0.148X Like this, the passing time was different between the tea seasons.
The passing time decreased with increasing the shoot length, and this tendency was distinct at a small angle.
The passing time of tea leaves of progressed maturity was shorter than that of the young shoots.
The difference of the passing time at the same angle could be expressed by the weight of dry matter and the bulk of tea leaves which were thrown into a steaming machine. Then, the multiple correlation coefficients of equations were statistically significant.

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The heat flow and the thermal efficiency of a tea drier were examined in order to obtain the data for energy reduction in tea mannfacturying. The experiments were carried out by using a tea drier of 60 K-1 type in the 3 rd crop season of 1983, and the results were as follows.
1. The required heat for tea drying process did not change significantly in the range of experimental conditions (set temperature; 70, 90, 110°C. air-tea ratio; 0.19, 0.26Nm³/min•kg (green leaves)). The required heat was calculated to be about 413.8 kcal/kg (crude tea) and about 12.6% of that was used as the heat of evaporation.
2. The turnace efficiency did not change in the range of these experimental conditions, however, drier efficiency rised as temperature was raised or air quantity was increased.
3. In the range of the experiments, the average thermal efficiencies were 85.6% for the furnace, 16.5% for the drier, and 13.9% altogether.

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