Highly conditioned greenhouses, including plant factories, are expected to provide greater product availability for increasing food requirements, especially here in Japan. There are generally two types of lighting systems employed at plant factories. One is a sunlight system and the other is an artificial light system. The sunlight system requires that a massive amount of expensive glasses be installed all around the sides of a greenhouse, which causes the structure to be relatively weak. This problem raises the costs of construction. To counteract the situation, we have conducted a study on how to efficiently use sunlight with reflective materials on the internal side walls of a greenhouse. Firstly we verified the effect of the reflection through a numerical simulation and some basic experiments, in which the illumination of a rectangular space on the floor was measured. The illumination on the floor and the growth of the test plants were seen to greatly improve through the use of the reflecting walls. The results of this experimental study are helping us to realize the potential of employing less glass in greenhouses and the possibility of applying freer designs to their structures. We also investigated a lighting system for thermal control, whereby sunlight is converted into thermal energy. In this system, the energy is stored in thermal-preserving materials during the daytime and then used for heating during the nighttime in winter. We confirmed the applicability of this system through an experimental study. Finally, we proposed a new system for conditioned greenhouses which uses natural energy more efficiently and offers more flexibility in the structural and the architectural designs.

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The Genus Torenia is comprised of 40 species. Horticultural cultivars, however, have the problem of a low genetic diversity, because the cultivars originated from only Torenia fournieri. For the purposes of the enhancement of genetic diversity in this study, we investigated interspecific cluster analysis based on the sequence of the internal transcribed spacers (ITS) of nuclear ribosomal DNA among 8 species of Torenia: T. fournieri (TF), T. glabra (TG), T. asiatica (TA), T. concolor (TC), T. baillonii (TB), T. sp-1 (SP1), T. sp-2 (SP2) and T. ‘Summer Wave’ (T. fournieri×T. sp-1)(SW), and the cross compatibility among each species by diallel cross. From the results of phylogenetic cluster analysis by nrDNA and ITS region sequences, the 8 species were classified into two clades: one consisted of TA, TC and TF, and the other consisted of TG, TB, SP1, SP2 and SW. From the diallel cross results, a high cross compatibility was recognized in the crossing of TC×TG, TC×SP2, TG×TC, TG×SP2 and SP2×TG. From the analysis of the form of progenies by these crossings, the progenies by crossing between SP2 and TG, which belonged to the same clade, had a prepotent form of TG, and the progenies by crossing between TC and TG or SP2, which belonged to different clades, had flower form intermediate between parents. Cross compatibility was recognized in the crossing among TG, TB, SP1 and SP2 which belonged to the same clade, because fruit set was recognized at least on their crossings with TB. TF, TA and SW had incompatibilities except for some parts. The progeny by crossing TB and TF had a clearly different flower shape and color compared with TF.

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In potted miniature rose production under recirculating Ebb&Flow system, the evapotranspiration was predicted from potential evapotranspiration, which was calculated by Penman Method, and total leaf area, which was predicted from meteorological factors. From the relation of evapotranspiration between observed and predicted by total leaf area, the evapotranspiration calculated from predicted total leaf area tended to be higher than that observed, and it was suggested that the evapotranspiration had to calculate from potential evapotranspiration and leaf area corrected by leaf area index (LAI). The evapotranspiration calculated from leaf area corrected LAI and potential evapotranspiration by Penman Method had close relation with the observed evapotranspiration, and a highly significant linear regression equation of Y=1.07X (R²=0.75) was obtained between both evapotranspirations. And the evapotranspiration every 30 min might be predicted by air temperature, humidity and solar radiation. However, there was large difference between evapotranspiration observed and predicted in early growth stage within 10 days after hard pinch and latter growth stage with over 2.8 in LAI, the differences between evapotranspirations in these stages made precision of estimate equation for evapotranspiration decline. A close correlation was observed between soil water volume in pot and pF, and water content of pot soil at pF 2.1 was 93.0 ml pot^-1. The field capacity of the pot soil was fixed at 210.0 ml pot^-1 regardless growth stages and cultivation periods of potted miniature rose, and the amount of available water for plant in a pot, which was equal to total evapotranspiration, was estimated at 117.0 ml pot^-1. Although it is within the growth range limited, the evapotranspiration in potted miniature rose production was predicted by air temperature, humidity and solar radiation from the results in this paper, and we might be able to predict watering time point in potted miniature rose production through weather data in greenhouse.

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The establishment of intraspecific hybrid plant between two varieties of common buckwheat plant was examined by in vitro flowering, in vitro pollination, fertilized flower/ovule culture, subsequent backcrosses and possible line establishment by micropropagation procedure. Varieties Kitawasesoba and Fukuizairaisoba were selected as mother and father plants, respectively. The fertilization and subsequent plant regeneration in vitro were significantly improved by the application of coconut water. About 40% of pollinated flowers cultured in coconut water medium grew into fertilized ovules and about 35% of pollinated flowers grew into immature embryos. All the embryos grew spontaneously into young plants.
In vitro born plants were identified as hybrid plants by zymogram, RAPD, and morphological and agriculture traits.
After the first in vitro cross, 3 backcrosses in vitro were sufficient to produce hybrid plants that had 94% of maternal genes. These plants were obtained in 240 days. One life cycle took about 55-60days in vitro in the present research. In vitro born plants were micropropagated in vitro to establish potentially stable lines. Possibility of cross breeding of plants in vitro to develop breeding factory is discussed.

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In the past, when a transport vehicle was moved on soft ground in a horticultural greenhouse and turned to a different direction at an end of a furrowed track, the surface of the track was made uneven by the tires in some cases. There are so called “multi-sheets” present not only over raised areas but also over furrowed areas in strawberry greenhouses, and there were also instances where multi-sheets were broken by tire sidewalls when the vehicle was steered. As a measure to overcome this problem, we developed a three-wheeled transport vehicle which could move along furrows in greenhouses without breaking multisheets. We focused on the shape of the wheel in this development, developed a globular wheel equipped with a special steering mechanism, which changes the steering angle and camber angle together when the vehicle is steered, and adopted it. We analyzed the steering characteristics and moving performance of this transport vehicle, and identified the following:First, in testing the frictional characteristics of the ground contact area of a tire, it was effective to make the COF between the tire and multi-sheet smaller than that between the multi-sheet and weathered granite soil (0.53). Next, the stress acting on a multi-sheet measured 4.3 Mpa when the globular wheels were steered, which was a small value just equivalent to 58% of that of general tires, so that using the globular wheels was effective enough to protect multi-sheets.Finally, the climbing performance of this transport vehicle was 18° when a tire material with a COF of 0.5 was adopted, and this was sufficient for practical use.

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To detect moisture by dew condensation, precipitation and fog cooling in plant production,an electric resistance-type wetness detector was developed and tested. The detectingelectrode was produced by precise electronic circuit board technology using photoengraving.The electrode pattern was applied to the fractal curve, and the electrode gap was designatedas 250 μm. Tests using a trial manufactured detector were able to detect dew condensationwith high sensitivity, and worked effectively as a feedback sensor for the controller of thefog cooling system in greenhouses. The manufacturing cost of a case of 50 wetness detectioncircuit boards was 4830 yen per board.

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