An automatic fogculture system for year-round rice production was developed. Its purpose was to reduce natural and environmental damages on rice production and farmland. Two rice cultivars, Koshihikari and Harebare, were grown from Mar. 12, 1992 to Aug. 24, 1992. Because the amount of sunlight was decreased to one-third of normal light intensity, growth and development of the two cultivars was very uneven. Yield of Koshihikari which was the better developed of the two, was 808 kg/10a. The yield of Harebare, which did not grow well, was 23 kg/10a. If this system was given enough sunlight and had a controlled temperature, a higher yield may be possible.

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農業用ロボットの把持機構に,軟質な対象物に対しても対応可能なワイヤハンドと位置検出を行う視覚装置を試作した.この装置を市販のマニピュレータに装着し,視覚装置の精度,対象物の形状及び色相に対する適応性及び模擬果実による収穫実験で制御特性を検討した結果,以下の知見を得た.
(1) 位置決め機能及び距離測定機能を有する視覚装置の精度は,平均2.4mm,最大25mmであったが,誤差の対処はプログラムによって十分可能であった.
(2) 対象物の形状に対する適応性は球形のものに対してはほぼ問題はなかったが,直方体,円筒のものに関しては一部動作が正常に機能しない場合があった.しかし,実際の植物体は球面形状を有する場合が多く,事前情報を与えることにより,対処可能と考える.
(3) 対象物の色相に対する適応性は赤色光のレーザビームを用いたため,青,緑色系の色相に対して約1.8倍ほど最大検出距離が短縮された.この距離は容易に変更可能で,マニピュレータの可動範囲内は十分機能した.
(4) 収穫所要時間はサーチ動作を含んで最大約25秒,サーチ動作を含まない場合で約16秒を要した.ハンドの移動による機械的走査によって対象果実のサーチを行うため,多くの時間を要することは否めないが,比較的良好に動作した.

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A new tissue culture medium was developed by mixing colloidal buffer agents together with tissue culture medium solution. Powders of zeolite, bentonite and charcoal were added to the medium solution as colloidal buffer agents. By adding colloidal buffer agents, the buffering capacity of pH in the medium increased significantly against both acidification and alkalization. When embryos taken out from Phaseolus vulgaris seeds were grown in media containing colloidal buffer agents, the length of plantlets formed from the embryos became larger and the dry weight of the plantlets became heavier than plantlets grown in media containing no buffering agents. This suggests that colloidal buffer agents stabilize the pH of the culture medium and sustain cell elongation and growth of plantlets for growing period during tissue culture. Furthermore, the addition of colloidal buffers in culture media had an additional benefit of preventing the degradation of organic substances in the culture media while the media were heated for the purpose of sterilization.

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The affects of day-length on flowering in strawberry cv. 'Ai-berry'were investigated.
In the plots which were treated for 20 days prior to planting by short-day and low temperature (8 hours day-length, 20/12°C day-night), 1st and 2nd cluster were flowered. Flowering of 3rd and 4th cluster were promoted by 11 or 12 hours day length after planting. But, natural day-length inhibited flowering of 4th cluster.
In the plots which were not treated by short day and low temperature, first and second cluster were flowered under 11 hours day-length. However, flowering rate was very low under 12 hours day-length. Flowering was not occurred completely under natural day-length.

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The effects planting time (A : At 2 weeks before starting of short-day treatment, B : At the starting of short-day treatment, C : At the end of short-day treatment), and starting time of nutrient supply (1 : At 2 weeks before starting of short-day treatment, 2 : At the starting of short-day treatment, 3 : At the end of short-day treatment) on flowering and yield in strawberry cv. 'Ai-berry', were investigated.
In the plots which were planted 2 weeks before short-day (SD) treatment (treatment A), almost plants flowered on every starting time of nutrient supply, but early nutrient supply delayed flowering. In B3 and C3 plots. flowering were delayed, and the rate of flowering were about 80% by treatment B3 and C3. Flowering was inhibited in B2 treatment.
The earlier nutrient supply to the plant that grown 2 weeks before flower induction (10 hour day-length), the yield was more increased.
Vegetative buds were often aborted in A3 and B3 plots, because of the concentration of NO₃^- of the petiole was low during flower induction.
Thus, planting before flower induction and supplying nutrients through-out the cultivation should be suitable for strawberry production in plant factory.

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