Increasing the biomass productivity of rice is a critical research target for improving the yield potential. This paper reviews ecophysiological studies on biomass production as affected by agronomic techniques and cultivars. In addition, we examined the effects of the planting pattern on the biomass production using cv. Takanari, a high-yielding and lodging resistant cultivar. The results showed that greater biomass production and grain yield were observed in plants with the combination of one plant per hill, high hill density and square hill arrangement. The factors responsible for high biomass production in this combination are; (1) vigorous tiller increase at the tillering stage resulting in higher capture of solar radiation, (2) erect leaves in the canopy after the panicle formation stage resulting in an improved light-intercepting character or smaller extinction coefficient, and (3) larger nitrogen accumulation during the ripening period resulting in a smaller decline of photosynthesis as well as a smaller midday and afternoon depression of photosynthesis possibly related to the larger water uptake ability of roots owing to better root-system development. Our results implied that an improvement in biomass production and yield is possible by optimizing the planting pattern and nitrogen management using high-yielding and lodging resistant cultivars in transplanted and direct-sown rice.

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A shoot elongation model was constructed for prediction of mulberry growth that tried to use the length as a growth index. In the model, the shoot elongation rate was represented as the product of growth activity (GA) and potential rate (PR) which were defined as growth activity of mulberry shoot tips and the potential rate of shoot elongation realized at the maximum GA under a given environmental condition, respectively. GA and PR were functions of temperature, photoperiod and/or shoot length. The model was applied to shoot length data of three cultivars grown in a wide area in Japan, and its parameters were determined. The shoot lengths calculated by the model were similar to the measured values and represented annual fluctuation well. The model also showed good estimation of data which were not used for determining parameters. Therefore, the model is practical and seemed to represent the response of mulberry vegetative growth to temperature and photoperiod well.

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The present study assessed nonlinearity in habitat preferences of Japanese medaka (Oryzias latipes) using genetic algorithm-optimized fuzzy habitat preference models incorporating the environmental factors of water depth (depth), current velocity (velocity), lateral cover ratio (cover), and percent vegetation coverage (vegetation). A linear relationship appeared between habitat preferences for cover and vegetation, which suggest the independent relationship between two factors. The habitat preference for velocity was found to have a nonlinear relationship with those for cover and vegetation, which appeared as different preference curves evaluated by the single-factor model. The habitat preference curves were affected by interactions between the environmental factors, especially those with nonlinear relationships, which resulted in different predictions of spatial distribution of the fish. Based on the present results, the use of a multiplex modeling approach, as applied in this study, would be appropriate to achieve better prediction accuracy, thus leading to more reliable habitat evaluation.

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To isolate and measure intact 4-methylthio-3-butenyl glucosinolate (4MTB-GSL) in Japanese radish, we applied a paired ion chromatography method that uses tetradecylammonium ions (TDA) as counter ions. 4MTB-GSL was isolated as ammonium salts from the root of a Japanese radish and identified on the basis of myrosinase treatment, aglycon detection, negative fast atom bombardment (FAB)-mass spectra, and a UV spectrum. The linearity of the prepared standard solution and recovery of that added to Japanese radish extracts were high.

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The direction of the agricultural trade flow compared with the total trade flow can exhibit different patterns. In this study, total and agricultural trade flows for Indonesia, Malaysia, Philippines, and Thailand were examined employing a gravity model and utilizing cross section data. The results show that income and population are significant and positive in all cases while ASEAN has a facilitating impact on the agricultural trade flow in general. Although the distance variable is negative and significant for total trade flow, it is not significant in some cases for the agricultural trade flow. Given the fact that the population has a tendency to increase and income rises with the process of globalization, increasing trade flow can be expected in the region over time. Trade facilitating measures such as harmonization of regulations and an appropriate marketing mix towards partner countries will increase the trade flow in the region

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A new animal calorimeter using a ventilated hood was constructed in Thailand. The recovery rates of our head cage were 96.5%, 97.0%, 95.7%, and 101.8%. The recovery rates of our head cage (95.7-101.8%) are reliable compared with Japanese whole-body chambers. The 99% CO₂ recovery time of our head cage was an average 14 min. It was shorter than whole-body chambers because of smaller effective volume and higher flow rate. Our head cage system excels at dynamic measurement of heat production. We started accumulating data concerning the energy value of Pangola grass (Digitaria eriantha) using 4 Brahman steers (body weight, 372.8 ± 34.4 kg, mean ± standard deviation; age, 3 years old). They were fed Pangola grass for 21 days; the grass was harvested approximately 45 days after cutting in several farms around Bangkok. Digestible energy and metabolizable energy of Pangola grass hay in our study were 10.28 and 7.99 MJ/kg dry matter. The average volume of methane production was 228.3 L/day and energy loss in the form of methane was 0.097 of the gross energy intake. These values are acceptable when compared with those obtained when low-quality tropical feed is provided to the steers.

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The effect of lighting to rotifer culture water was investigated preliminarily using freshwater Chlorella as food in terms of vitamin B₁₂ (VB₁₂) production. The marine rotifer Brachionus plicatilis was batchcultured for five days at 25°C in 25 psu seawater with or without lighting (L:D = 13:11 and L:D = 0:24). Rotifers were fed VB₁₂-enriched or VB₁₂-free Chlorella vulgaris with or without cobalt compound supplementation (cobalt (II) sulfate heptahydrate: CoSO₄•7H₂O). When VB₁₂-enriched Chlorella was fed, rotifer with lighting showed better population growth than in complete dark. On the other hand, no difference was observed in the population growth between light and dark groups when VB₁₂-free Chlorella was used. Nevertheless if the cobalt compound was supplemented to VB₁₂-free Chlorella, the light group showed higher population growth than non-supplemented groups and dark groups, and a much higher amount of VB₁₂ was detected from the tanks than those from other groups. In addition to that, even in the group fed VB₁₂-free Chlorella without Co supplementation a daily increase of a small amount of VB₁₂ was observed when they were lit up. From these experimental results, we can conclude that lighting plays an important role for the population growth of rotifers and Co compound supplementation to rotifer culture water promotes the reproduction performance of rotifers due to the enhanced production of VB₁₂ by lighting.

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