Publisher：CROP SCIENCE SOCIETY OF JAPAN  

DOI： 10.14829/jcsproc.251.0_103

Publisher：CROP SCIENCE SOCIETY OF JAPAN  

DOI： 10.14829/jcsproc.251.0_139

Publisher：日本作物学会  

DOI： 10.14829/jcsproc.251.0_106

Publisher：日本作物学会  

DOI： 10.14829/jcsproc.251.0_102

Publisher：Annals of Agricultural Sciences  

DOI： 10.1016/j.aoas.2020.09.002

Scopus

Publisher：Plant Production Science  

DOI： 10.1080/1343943X.2020.1730699

Scopus

Language：English   Publishing type：Research paper (scientific journal)  

Publisher：IOP Conference Series: Earth and Environmental Science  

DOI： 10.1088/1755-1315/418/1/012080

Scopus

Publisher：Rice Science  

DOI： 10.1016/j.rsci.2019.12.007

Scopus

Publisher：CROP SCIENCE SOCIETY OF JAPAN  

<p>Cassava (<i>Manihot esculenta</i> Crantz) is highly productive in the tropics and sub-tropics, including marginal conditions. A high starch content cultivar IAC-576-70, selected at the Instituto Agronômico de Campinas, São Paulo, Brazil, was grown in a field in Kagoshima Prefecture during cropping seasons from 2007 to 2009, to determine its capability as a biomass source even in a temperate region of southwest Japan. At the experimental site, the annual mean temperature was 18.3°C with several incidences of frost in winter and annual mean rainfall of 2280 mm (for years from 1971 to 2000). Under these conditions, cassava grew for 8 months from late April to mid-December, and produced a total dry weight of 1793 g m^–2, tuberous root dry yield of 524 g m^–2 and tuberous root fresh yield of 2000 g m^–2. The yield in Kagoshima was equivalent to that at 8 months after planting in tropical regions.</p>

DOI： 10.1626/jcs.89.277

Publisher：CROP SCIENCE SOCIETY OF JAPAN  

DOI： 10.14829/jcsproc.249.0_111

Publisher：日本作物学会  

DOI： 10.14829/jcsproc.249.0_102

Language：English   Publishing type：Research paper (scientific journal)  

Publisher：Australian Journal of Crop Science  

DOI： 10.21475/ajcs.19.13.11.p2046

Scopus

Language：English   Publishing type：Research paper (scientific journal)  

Publisher：Agronomy  

DOI： 10.3390/agronomy9050236

Scopus

Publisher：CROP SCIENCE SOCIETY OF JAPAN  

DOI： 10.14829/jcsproc.247.0_71

Publisher：CROP SCIENCE SOCIETY OF JAPAN  

DOI： 10.14829/jcsproc.247.0_29

Publisher：CROP SCIENCE SOCIETY OF JAPAN  

DOI： 10.14829/jcsproc.248.0_115

Publisher：CROP SCIENCE SOCIETY OF JAPAN  

DOI： 10.14829/jcsproc.247.0_30

Publisher：CROP SCIENCE SOCIETY OF JAPAN  

DOI： 10.14829/jcsproc.247.0_52

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Publisher：Biomass and Bioenergy  

DOI： 10.1016/j.biombioe.2017.12.026

Scopus

Publisher：日本熱帯農業学会  

<p>Jatropha (<i>Jatropha curcas</i> L.) is well-adapted to arid areas and thus has been recognized as a new energy crop for bio-diesel production in Africa. Low temperatures due to radiative cooling effects are known to cause frost damage to jatropha and this is an important limiting factor of its cultivation in Gaborone, Botswana. To mitigate heat loss at night and rapid increments of light intensity and air temperature after dawn, shading screens were applied to field-grown jatropha. Then, the protection effects and the photosynthesis after being damaged by frost were examined. Cold waves severely damaged branches and leaves of jatropha trees; however, this damage was greatly alleviated by the shading treatments. Without shading, nearly half of the branches showed blackened apexes and most of the leaves had fallen off, while only a few branches were damaged and a number of leaves were maintained in the shading plots. The number of inflorescences was also higher in these plots though it was investigated earlier than the flowering period, therefore further observation is surely necessary. Photosynthesis measurements suggested that shading significantly reduced CO₂ assimilation and transpiration rates of jatropha leaves due to the limited sunlight, yet the shaded leaves properly functioned in response to changing light intensity. From these results, it was concluded that shading was an effective technique to protect jatropha branches and leaves from frost damage, which may have further improved inflorescence formation as well. Shading screens need to be removed after winter to increase light availability and enhance photosynthetic ability.</p>

DOI： 10.11248/jsta.62.158

Publisher：CROP SCIENCE SOCIETY OF JAPAN  

<p>Sunflower has been cultivated as a decorative plant in subtropical Okinawa; however, the optimal sowing time and suitable cultivar for oil production have not yet been determined. In this study, six cultivars were grown in four seasons and the growth and yield characteristics were examined to determine the optimal sowing time and suitable cultivar in the region. The effective accumulated temperature from emergence to flowering was 1000–1100°C, and some cultivars showed lower values under short day conditions in autumn and winter sowings. Sunflower can be grown year round in Okinawa because the temperature in winter is above 10°C. However, it is important to consider lodging due to typhoons during the seed harvesting season in sunflower sown in spring or summer (July–October). The results revealed that high growth rates before and after flowering were important for obtaining high yields in sunflower sown in autumn and winter; however, the yield was lowered by decreased biomass at flowering and reduced number of seeds caused by high temperatures in spring and summer. Therefore, the optimum sowing time to harvest sunflower seed for oil production was considered to be from the beginning of October to the beginning of February. By using cultivars that are photosensitive and have a high growth rate after flowering, a high seed yield of 300 kg 10 a⁻¹ and high oil yield of 110 kg 10 a⁻¹ could be obtained.</p>

DOI： 10.1626/jcs.87.223

Publisher：一般社団法人　園芸学会  

<p>In Japan, several plant species have high commercial value because of their functional properties. In this study, we aimed to investigate the effects of soil type (red, dark-red, and gray soil) and growth stage (vegetative and reproductive) on the growth and polyphenol production (chlorogenic acid, rutin, hesperidin, and diosmin) of <i>P. japonicum</i>. Plants grown in gray soil had the heaviest dry weight, followed by those grown in dark-red soil. Flowering plants grown in gray soil had a polyphenol concentration lower than those grown in the other two soil types. However, differences in the concentration of polyphenols were even larger between the growth stages. During the flowering period, the concentration of polyphenols sharply increased in the stems. Additionally, the flowers contained relatively similar amounts of polyphenols to stems and leaves, accounting for approximately 1/4–1/2 of the net amount in the plant.</p>

DOI： 10.2503/hortj.OKD-069

Scopus

Language：Japanese   Publishing type：Research paper (scientific journal)  

Publisher：Sugar Tech  

DOI： 10.1007/s12355-016-0486-2

Scopus

Language：English   Publishing type：Research paper (scientific journal)  

Publisher：日本熱帯農業学会  

<p>Oilseed sunflower (<i>Helianthus annuus</i> L.) has a lower seed yield and harvest index than other oil crops, and consequently produces a large amount of residue such as stem, receptacle, and oil cake. Our study attempted to use these residues as biochar for improving soil fertility, sunflower growth, and yield in subtropical island, Okinawa, Japan. To reveal the synergistic effect of biochar and inorganic fertilizer, we established four treatments: biochar (B), biochar + fertilizer (BF), fertilizer (F), and control, using biochar derived from bagasse (Exp. 1) and sunflower residue (Exp. 2). As a result, biochar application improved soil fertility, including soil electrical conductivity and mineral concentration. In spite of the initial positive effect of biochar application to plant growth this effect became negative later. The reason for this response might be the reduction of the net assimilation rate (NAR) during the later growth stage due to nitrogen deficiency after biochar application. Biochar application had a positive effect on sunflower growth during the early growth stage when the leaf area index (LAI) was dominant for the crop growth rate (CGR), while this effect became negative during the later growth stage when the NAR was dominant for the CGR. Further research is required to determine the effects of biochar application depending upon application methods, plant growth stages, and plant species.</p>

DOI： 10.11248/jsta.61.32

Publisher：Japanese Society for Tropical Agriculture  

<p>Jatropha (<i>Jatropha curcas</i> L.) has been widely introduced to the Tropics and Subtropics as an energy crop because it can be grown in the dry climate and in various soils without competing with food production due to its toxicity. Foliar application of BA (6-Benzyladenine) may increase the yield through enhancing the number of the fruit. However, too much fruit may also cause fruit drop and shortening of harvest due to exhaustion. This study investigated the effects of BA on the seed yield throughout the harvest season. 120 one year old cuttings were transplanted to the field on April 24, 2013, and 72 plants were treated with BA on September 6 when the first flowers appeared. The flowering percentage, the number of flower sets and fruit bunches were counted from the 9th day before the treatment started to the 148th day after starting the treatment (DAT). The number of fruit was counted on 69 DAT. Harvesting was started from 82 DAT, and the characteristics of the seeds were analyzed. The BA treatment reduced the number of fruit bunches towards the later harvest time by restricting the second and third flower set initiations. However, the number of fruit was greater in the BA treatment mostly due to the increased number of fruits for the first bunch. As a result, seed yield was higher in the BA treatment (44.0g plant ^-1) than in the control group (38.6g plant ^-1). As a further improvement of the yield would be expected through increasing the fruit bunches, the method of application should be tested.</p>

DOI： 10.11248/nettai.10.51

Language：Japanese   Publishing type：Doctoral thesis