In cool climates, direct-sowing in early winter is an effective technique to improve rice productivity. We evaluated the effect of chemical treatment of rice seeds and harvest year on the seedling establishments. The most effective chemical was Thiuram (“Kihigen-R2-Furoable”; KG) among 26 combinations of chemical and material applications, which improved the seedling establishment approximately 17 points compared to the percent seedling establishment of non-treated control seeds (3～9%). In addition, harvest year strongly affected the seedling establishment; that is, the seeds sown in the year they were harvested gave better establishment than the seeds harvested in the previous year. The seeds sown in the year they were harvested showed greater dormancy than the seeds harvested in the previous year. An artificial dormancy-break treatment severely reduced the seedling establishment. These results showed that “KG” improved rice-seedling establishment, and that seed dormancy was important to attain high seedling establishment in direct sowing in early winter.

Priming is attracting attention as a method for promoting seed germination and emergence under stress conditions of drought and low temperature. A few reports on rice seed priming are available; however, its effects on the germination and emergence of Hokkaido rice cultivars under low-temperature environments remain unclear. In this study, low-temperature effects on seed germination and emergence were investigated by soaking seeds in water (hydropriming treatment). The rice varieties used, mainly consisted of direct sowing cultivars of Hokkaido, Japan. The immersion time in water at 25°C for 18 h, was considered an optimum condition by a test using “Sansanmaru” and “Hoshimaru” varieties, for direct seeding cultivation in Hokkaido. Cultivars subjected to priming showed a tendency toward accelerated early seed germination and emergence at a low temperature in comparison with non-treated test cultivars, and a substantial promoting effect was observed in “Sansanmaru” and “Daichinohoshi” varieties, in particular. The priming treatment could assist direct seeding cultivation in cold regions since the promotion effect on germination and emergence under low-temperature environments was widely observed in the Hokkaido cultivars.

A fertilizing system that reproduces “intensive nitrogen fertilization during stem elongation (INFDSE)” with controlled-release fertilizers (CRF) would be useful for wheat production aiming at high yield and quality, and low labor cost. In trials at Kumamoto prefecture, one-shot fertilizing with crotonylidenediurea (CDU), isobutylidenediurea (IBDU) and coated urea produced a yield similar to that obtained with INFDSE. One-shot basal fertilizing with IBDU and CDU at the 4th leaf stage in 2016/17 (sown in winter of 2016 and harvested in spring of 2017) produced a lower grain protein content than INFDSE although other treatments using CRF produced a similar grain protein content. In one-shot top-dressing with urea and CDU at the stem elongation stage (U+CDU_SE) and basal coated urea at basal (LP30), the aboveground nitrogen accumulation at maturity was as high as that obtained with INFDSE. In trials at Yamaguchi prefecture, yield and aboveground nitrogen accumulation at maturity in the U+CDU_SE were similar to the values obtained with INFDSE in 2017/18. In the trials at Kumamoto, lodging degree after anthesis was high in the LP30, although no lodging was observed in one-shot top-dressing with CDU at the stem elongation stage due to shorter stem and internodes. One-shot application such as U+CDU_SE may be as productive as INFDSE while lowering labor cost.

Erianthus, a perennial C₄ grass, is gathering attention as a raw material for cellulosic bioethanol, mainly because it has high potential for biomass production based on its large canopy. During the annual regeneration of the population, differences arise among stocks of the population including disappearance in some cases. In the present study, we investigated the variation in growth and development of stocks in the Erianthus population year by year from the view-point of population ecology. Regardless of the year after planting, stocks with small numbers of stems were frequently observed, while those with large numbers of stems were seldom observed. Such a tendency became more pronounced year by year. In addition, the trend in annual changes after transplanting indicated that the growth variation increased with the canopy development of the population. The relationship between the growth variation and the competitive effect showed that the less the number of stems per stock, the larger the competitive effect. Cultivation of Erianthus over several years suggested that the law of constant final yield may hold. Thinning at an early stage of cultivation may increase the yield and inhibit the increase of growth variation of the stocks in the canopy.

Eddo is a crop that is vulnerable to drought, but there are no guidelines on the timing and amount of irrigation. In this study, the proper soil moisture and the method to control it were examined from the viewpoint of profitability. In 2015, soil moisture content was set at 15%, 25%, and 35% in terms of volume moisture content under rain-shelter cultivation. In 2017, 3 test plots were set: conventional plot (irrigation every seven days), 25% soil moisture plot and no irrigation plot. Merchandise yield (total yield of secondary and tertiary tubers) was high in the 35% soil moisture plot and the conventional plot (soil moisture of 30%), but the yield of the 3L-S size which had a high sales unit price was equivalent to or slightly higher in the 25% soil moisture plot than in the other two treatment plots. On the other hand, the yield of low-quality eddo was low in the 25% soil moisture plot. From these results, high profitability per unit area was attained by controlling the soil moisture around 25%.

Four near-isogenic lines (NILs) of Japanese soft wheat with different compositions of high-molecular-weight glutenin subunits, which are controlled by Glu-A1 and Glu-D1 genes were cultivated with different amounts of nitrogen fertilizer applied at flowering time. Using these flours, the effects of protein quantity and protein quality on baking quality (Japanese sponge cake (JSC) quality, sugar-snap cookie (SSC) quality and solvent retention capacity (SRC)) were evaluated. The flour protein content ranged from 7.7 to 11.7%. As flour protein content increased, JSC specific volume, SSC diameter and SSC spread factor decreased and showed a significant negative correlation with flour protein content. JSC specific volume was not significantly different among the NILs. SSC diameter, SSC spread factor and lactic acid SRC were significantly different and null at the Glu-A1 locus (Glu-A1c) was associated with larger SSC diameter, larger SSC spread factor and lower lactic acid SRC. JSC specific volume, SSC diameter and SSC spread factor showed a negative correlation with lactic acid SRC, but the correlation with lactic acid SRC was weaker than that with flour protein content. These results suggested that protein quantity strongly affected baking quality and suggested that Glu-A1c had a positive effect on SSC quality.

We investigated the characteristics of rice grains distributed on the market in China to clarify their quality, palatability and stored substance structure. Surveys were conducted in Shanghai city, which has a large population and many types of staple rice. According to an interview survey, citizens preferred milled rice from Heilongjiang and Liaoning provinces in northeast and Jiangsu province. In particular, milled rice, varieties “Wuchang Dami” and “Qiutian Xiaoting” from the northeastern region and milled rice variety “Sheyang Dami” from Jiangsu province were preferred. Amylose and protein contents were low in “Wuchang Dami” and “Qiutian Xiaoting”, and high in “Sheyang Dami”. Scanning electron microscopical observation of cooked rice revealed that a fine fibrous structure on the surface, a large membranous structure in peripheral layer, and a porous structure in the inner portion were observed in “Wuchang Dami” and “Qiutian Xiaoting”. While, in “Sheyang Dami”, although fine fibrous structures were observed on the surface, development of inner porous structure was insufficient, and protein granules were scattered in middle and central parts with insufficient gelatinization. These structures were similar to those in rice with “high- or low-palatability” in Japan. These results suggest that most of the milled rice sold and eaten in Shanghai city is similar in quality and palatability to milled rice marketed in Japan, with similar ultra-fine structure of cooked rice. It was also found that rice with high quality and palatability is generally distributed and sold in Shanghai city.

Demand of rice grains from the cultivar “Yamadanishiki” for sake brewing is increasing in Yamaguchi prefecture. However, steady supply of high quality grains is still difficult. The objectives of this study are to determine the relationship of output value S1 obtained by proximate remote sensing, with nitrogen accumulation in plants, yield, spikelet number and protein content of brown rice in “Yamadanishiki”. The analysis was carried out in rice fields with different levels of nitrogen fertilization applied at different stages and with different levels of soil fertility in 3 cropping seasons (2016–2018). The nitrogen accumulated in plants, spikelet number, and protein content of brown rice showed a positive correlation with the S1 value. From the correlation, the targeted range of S1 value at full heading was established to control spikelet number and protein content rate at proper levels. The S1 value at full heading increased with increase of nitrogen fertilizer at the panicle formation stage. Therefore, the target S1 value at full heading could be achieved by measuring the S1 value at the panicle formation stage, and by calculating and applying the proper amount of nitrogen fertilizer.

An estimation formula for the grain protein content of the bread wheat cultivar “Setokirara” was constructed by measuring yield and the amount of nitrogen topdressing at anthesis. A data set used for constructing the formula was collected at the fields in Yamaguchi Prefectural Agriculture and Forestry General Technology Center for three years. Multiple regression analysis was used to determine the coefficients of the explanatory variables, and were found to be –4.056×10^–3 for yield and 0.517 for nitrogen topdressing. The interaction effect was excluded from the formula because it was not significant. Results demonstrated that the grain protein content of “Setokirara” decreased by 0.406 points as the yield increased by 100 g m^–2. Additionally, the grain protein content increased by 0.517 points when 1 g m^–2 of nitrogen topdressing was added. The formula was varified using “Setokirara” datasets collected from either the Technology Center (TC) or from a farmer’s fields located in the southern part of Yamaguchi city (FF). The root mean square errors for TC and FF were 1.4% and 2.2%, respectively. The error at FF was larger than that at TC. One reason may be that topdressing application was earlier than anthesis at FF. These results indicate that the formula can estimate grain protein content of “Setokirara” by yield and the amount of nitrogen topdressing at anthesis althogh the error rate may depend on variations in crop management.

A new peanut cultivar ‘Chiba P114’ has a high sucrose content. However, its sucrose content is not always high. Its branches are also too long for harvesting. In order to produce peanuts with a high sucrose content and to improve the harvesting operation, we investigated the effects of shoot trimming on the yield and seed quality. The earlier the shoot was trimmed, however, the greater the decrease in yield. However, shoot trimming at 70 days after flowering increased the sucrose content, regardless of sowing date. The results showed that shoot trimming at 70 days after flowering would be an appropriate practice for production of peanuts with a high sucrose content while minimizing the reduction in yield.

To extend the harvest period of forage rice with short panicles, we compared the dry matter yield and nutritive components of two cultivars with different heading dates from late August through October. In addition, we investigated whether nitrogen top-dressing at the booting stage effectively increases crude protein content. There was no significant difference in dry matter yield between “Chugoku Shi-224” (an early-heading strain) and “Tsukisuzuka” (a late-heading cultivar) until September, whereas the yield of “Tsukisuzuka” was higher than that of “Chugoku Shi-224” in October. The sugar content in leaves and stems, which plays an important role in the fermentation of silage, was lower in “Tsukisuzuka” than in “Chugoku Shi-224” until early September but was similar in the two cultivars in October. Total digestible nutrients tended to be higher in “Chugoku Shi-224” until September but higher in “Tsukisuzuka” in October. There was no significant difference in crude protein content between the two cultivars, and nitrogen top-dressing increased the content in both cultivars without affecting dry matter yield. These results indicate that the cultivation of “Chugoku Shi-224” in addition to “Tsukisuzuka” enables the harvest of forage with high nutritive value in late August and September, when the nutritive components are not fully accumulated in “Tsukisuzuka”. Furthermore, nitrogen top-dressing at the booting stage appears to improve the nutritive value of forage rice by effectively increasing crude protein content.