A neural network system for predicting the mean and variance of normal distribution of characteristics (fruit weight, number of perfect seeds in a fruit, number of imperfect seeds, number of unfertilized seeds, citric acidity and Brix % of fruit juice) of ‘Tosa buntan’ fruit grown on the same tree branch was constructed. Its accuracy level of prediction was evaluated based on the probability concept. As a result, it was found that the probabilities of successful prediction ranged from 77.24% in number of imperfect seeds of fruit to 95.64% in citric acid degree.
Under these probability restrictions of prediction, the optimum cultivating conditions for ‘Tosa buntan’ were estimated by combining the neural network system and the Rosenbrock method as an optimizer. In the calculating process, a proximity which was defined as the product of the target fruit vector and the output vector from the neural network was used as the index for the optimizing level.
The results of the optimization revealed that there are no optimum cultivating conditions which satisfy all the required conditions for the best fruit. Instead, it gave the optimum cultivating conditions for producing the heaviest for fruit, those for obtaining the least seeds in fruit and for optimizing citric acidity, and those for obtaining the maximum Brix % of fruit as a second resolution.

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Leaf lettuce crops (Lactuca sativa L. cv. “Greenwave”) were grown in a plant production system using a Mirror Duct which intensified sunlight and transferred it to the inside of buildings. This system was expected to reduce the operational energy and lighting cost. The experiments were conducted under four photosynthetic photon flux densities (PPF) of 140, 160, 180, and 200 μmol m^-2s^-1, in two light conditions, fluorescent light only and fluorescent light plus sunlight transferred with the Mirror Duct, and were repeated five times in total from August 2002 to July 2003. Five different solution temperatures were finally obtained through all the experiments due to temperature changes inside the experiment facility. Variance was analyzed to estimate the effect of these environmental factors on the growth of leaf lettuce. It was found that the fresh weight of leaf lettuce increased as PPF increased and the rate of increase of weight was 0.6 to 1.0 g per unit PPF in both 17.4°C and 23.5°C solution temperatures; the solution temperature had a significant effect upon the fresh weight; and a difference in fresh weight at harvest of between 40 and 60 g was observed between 17.4°C and 23.5°C solution temperatures. The light containing 10% sunlight was not effective for increasing fresh weight at harvest compared to the fluorescent lamp.

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Hypocotyl and internodal explants were collected from in vitro grown seedlings and in vitro proliferated shoots, respectively. Callus induction and subsequent plant regeneration were established from those explants. Friable callus with somatic embryo-like structure (ELS) developed from hypocotyl and internodal explants on Murashige and Skoog (MS) medium supplemented with 0.89-4.44μM 6-benzylaminopurine (BAP) and 2.26-9.05μM 2,4-dichlorophenoxyacetic acid (2,4-D) or 2.69-10.74μM α-naphthaleneacetic acid (NAA). The maximal frequency of callus and ELS formation were obtained when the MS medium was amended with 0.89μM BAP and 4.52μM 2,4-D. After callus induction, they were cultured on the MS medium supplemented with 0.98-4.44μM BAP and 0.54-2.69μM NAA or 0.49-2.46μM IBA for the regeneration of the shoots. Among different hormonal conditions, a combination of 2.22μM BAP and 1.07μM NAA produced the highest percentage of shoot differentiation from calli. In vitro grown shoots were rooted on the MS medium with either of 0.5-4.0μM indole-3-butyric acid (IBA), NAA, or indole-3-acetic acid (IAA). Regenerants were transferred to Kanuma soil and successfully established under ex vitro environment.

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Effects of continuous lighting of fluorescent lamps with different light qualities on growth and dry matter production of pepper plants were investigated. Stem length was longest in red light, followed by white light and shortest in blue light. Comparison of continuous lighting (CL) and daily 12 hr-lighting (DL) in red and blue lights showed that stem length was longest in the case of CL-red, followed by DL-red, CL-blue, and shortest in the case of DL-blue.
Twenty days treatment showed that plant height of CL-blue was reduced by 70% of that of CL-red. These results indicate that blue light strongly inhibits stem elongation. However, leaf color turned dark green in CL-blue and lateral shoots sprouted earlier, on 1 st, 2 nd, 3 rd and 4 th nodes. These phenomena were not observed in the case of DL-blue.
Leaf area and dry weight of the shoot were highest in the case of CL-red, and corresponded to 1.7 and 1.4 times of the amount in CL-blue, respectively. However, photosynthetic rate on leaf area basis was similar among the treatments. Leaf area was 1.7 times larger in the case of CL-red than that of DL-red, and the ratio CL/DL in dry weight of the shoot was 2.6 which exceeded 2.0, the ratio of irradiated light energy. This result suggests that dry matter production of pepper plants involved in light use efficiency can be increased by continuous lighting of 100 μmol m^-2s^-1 PPFD.

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A simplified temperature control system for the unit-type multistage transplant culture system was developed and applied to tomato transplant culture using a small-sized refrigeration chamber. The transplant culture unit was installed into the chamber maintained at approximately 15°C. Air temperature inside of the culture unit rose to a higher temperature than the outside during the photoperiod. When the temperature inside of the culture unit reached a set point of 25°C, ventilation fans located above the transplants were turned on with a temperature controller, thereby decreasing the temperature inside the culture unit. The fans were turned off when that ventilation reduced the temperature inside of the culture unit below a predetermined temperature. In this manner, the culture unit temperature was controlled between 24.5°C and 26.5°C during the photoperiod even though the outside temperature fluctuated between 13.5°C and 17.5°C. After culture of 16 d, height of the tomato transplants in winter season culture were significantly more developed than in summer season culture, despite use of the semi-closed chamber of the equal temperature setting and artificial lights for both cultures. We infer that such growth resulted from the higher relative humidity in the winter culture than in the summer culture by seasonal variation of cooling load and refrigerator ability. The relative humidities inside of the culture unit in the summer and winter season cultures were 40% and 60%, respectively.

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