In order to hasten the pollen division in anther culture of tea plant, the effects of transplantation from the medium of 10% sucrose concentration to the 2% medium were investigated.
1) At one week after explant, the pollen grains having either one or two nuclei were observed.
The pollen grains in 11.2% of anthers divided more than two nuclei or two cells after two weeks culture, however the pollen grains in 22.1% of anthers degenerated.
Anthers with the divided pollen grains increas-ed by 13.4% at one week after transplant, moreover the pollens having more than four cells were observed and counted, therefore it was concluded that the transplant of anthers from the medium of 10% sucrose to the 2% medium is effective for acceleration of the pollen division.
2) The pollens divided more than four cells in the 25.9% of anthers in the medium with lppm of 2, 4-D concentration after two weeks of transplant. In the medium with 10ppm those decreased markedly (4.7%). Kinetin in concentration from O to 10ppm was not effective for the pollen division.
3) The development of multicellular pollen grains in anther culture of tea plant seems to depend on the division of vegetative nuclei as well as the case of Lolium and Nicotiana.

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In order to clarify the cause for "shoot rot disorder" of tea plants which had been occurred in tea fields in Kagawa prefecture, the effect of application of sawdust cattle compost into the Granite soil on the occurrence of "shoot rot disorder" was investigated.
1. Physical and chemical properties of the soil were improved by application of the compost. But "bud necrosis" occurred in compost applied plots of both cultivars Yabukita and Sayamakaori. And the Cu content of leaves and prunned branches in compost applied plot was low.
2. The content of 0.1 N HC1 soluble Cu in the soils at the beginning of the 1st flush was 0.3 or 0.15 ppm in compost unapplied or applied plots.
3. The "leaf tip necrosis" occurred in compost applied plot, and its occurrence in Yabukita was more remarkable than that in Sayamakaori. The yield of 1st crop in compost applied plot was about one half that of unapplied plot of Yabukita, but there was no differences in both plots of Sayama-kaori. The Cu content of the 1st flush shoots in compost applied plot was 1/3 or 1/2 that of unapplied plot of Yabukita or Sayamakaori.
4.The significant correlations were recognized between the percentage ot "leaf tip necrosis" leaves. Cu content of the 1st flush shoots and the 0.1 N HC1 soluble Cu content of the soils respectively.
5. From the results mentioned above, it was considered that "shoot rot disorder" of tea plants was due to deficiency symptom of Cu which was ascribable to a decrease in available Cu in the soil, and the occurrence limit of Cu-deficiency was about 0.2 ppm of the 0.1 N HC1 solublc Cu content in the soil. Furthermore, it was assumed that the available Cu decreased because of the absorption of Cu by the soil organic matters derived from compost.

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For the prevention of the occurrence of "shoot rot disorder" of tea plants, the effects of the foliar spray of Cu(OH)₂ solution and soil application of CuSO4•5H₂O which had been done after plucking of 1st and 2nd crops were investigated at the 2nd and 3rd crop seasons.
1. Few effects of the protection from the occurrence of the "leaf tip necrosis" leaves were re cognized at the 2nd crop, but the occurrence of the "leaf tip necrosis" leaves somewhat decreased only in Cu(OH)₂ foliar spray plots of Sayamakaori. However, the yields of cultivars Yabukita or Sayamakaori after Cu application were about twice that of control plots. Effects of the Cu(OH)₂ foliar sprays were remarkable at the 3rd crop, that is the "leaf tip necrosis" leaf was not observed in the plots of cultivar Sayamakaori.
2. The 0.1 N HC1 soluble Cu content of the soils at the plucking time of 2nd or 3rd crop was highest in the CuSO₄•5H₂O applied plots, followed by the Cu(OH)₂ foliar sprayed plots, and lowest in the control plots. And, the 0.1 N HC1 soluble Cu content in the compost applied plots were lower than that of the unapplied plots.
3. Cu content of the 2nd or 3rd flush shoots in the compost applied plots were lower than that of the unapplied plots, and the formers were 1/3 the latters in control plots. But Cu content in compost applied plots increased after Cu applications, and was 2/3 to that in the compost unapplied plots after Cu(OH)₂ foliar spray.
4. The significant correlations between the percentage of "leaf tip necrosis" leaves and the Cu content in the flush shoots at 2nd or 3rd crop were recognized, but no significant correlations between the 0.1 N HC1 soluble Cu content of the solis and percentage or the Cu content of the flush shoots were recognized.
5. From the results mentioned above, it was considered that Cu application was effective for the protection from the occurrence of the "shoot rot disorder" of tea plants, and the foliar spray of Cu(OH)₂ solution was more quickly effective than the soil application of CuSO₄•5H₂0.

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To investigate the occurrence of strains of the tea gray blight fungus Pestalotia longiseta and P. theae resistant to benzimidazole fungisides (Topsin M, Benlate), tea leaves affected by the disease were collected from 14 major tea-producing prefectures in Japan. An isolate from each diseased leaf was examined on PDA media containing thiophanate-methyl (Topsin M) of the concentrations of 0, 1, 100 ppm. The medium inhibitory concentration (MIC) for several isolates and the geographical distribution of the tea gray blight fungi Pestalotia spp., i. e. P. longiseta, P. theae were also analyzed. In 68 tea fields out of the 119 tested resistant strains (1ppm inhibition) were detected, although highly-resistant ones (100ppm inhibition) were obtained from 54 fields. The ratio of detection of the resistant strains in Shizuoka, Mie, Saga, Miyazaki and Kagoshima Prefectures was high, whereas in Tokushima and Kochi Prefectures resistant strains were not detected. Regarding the geographical distribution of the Pestalotia spp., most of the P. longiseta species were isolated in Shizuoka, Aichi, Mie, Shiga, and Nara Prefectures. While in Saitama, Tokushima, and Kumamoto Prefectures, the P. theae species were isolated more frequently than the P. longiseta ones.

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The effects of the addition of L-ascorbic acid to green tea infusion and the exchange of headspace volume with nitrogen gas before sealing process were investigated to prevent the deterioation of the infusion color and flavor during the pasterization of canned green tea drink.
From the results of the investigation, it was demonstrated that those treatments played an important role in the keeping of the quality of canned green tea drink during the pasterization.
A suitable concentration of green tea infusion for the canned green tea drink was obtained by using about one percent of green tea to a weight of hot water.

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Changes in both chemical constituents and physical properties of tea leaves during green tea manufacturing were examined.
The manufacturing of green tea consists of following processes: steaming, primary rolling, rolling, secondary rolling, final rolling and final drying.
The content of water extract, total nitrogen, tannin, caffeine, solublue nitrogen, free reducing sugar free amino acids, or vitamine C did not change during the manufacturing.
The amount of the above constituents extracted from leaves for 5 min increased in the primary rolling process and thereafter little changed.
Water soluble pectin was gradually reduced from the primery rolling process to the final drying process, but the contents of both salt-soluble and acid-soluble pectins did not changed.
Bulk density of leaves and the conversion ratio of chlorophyll to pheophytin increased re-mar kably during the process, and Hunter's L, a and b values were larger in steamed leaves than in leaves of the remaining processes.

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