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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Currently agricultural robots are being developed as one of the essential key technologies in a lot of endowed institution. However, it is supposed that some more time is necessary until agricultural robot technology is put into practical use.
In this study, a new mechanism using a wire for gripping a soft fragile object and a simple visual sensor with a line type CCD, were developed as one step of the fundamental studies of robotics in agriculture. These devices were mounted on a commercial robotic manipulator and tested with respect to the measurement accuracy and the adaptability to the shape and the color of objects for visual sensor, and harvesting experiment using a model fruit was done. From these experimental results, the followings were derived.
(1) Measurement accuracy of visual sensor was. 2. 4 mm in average, 25 mm at maximum.
(2) Adaptability to the shape of object was less problem for globe, however in case of rectangular parallelepiped and cylindrical objects, a little problem was observed.
(3) No problem was found for the adaptability to the color of object.
(4) Required time for harvesting one model fruit was 25 seconds at maximum and 16 seconds for the one with and without searching motion respectively.

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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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