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Tartary buckwheat (Fagopyrum tataricum(L.) Gaertn.) is considered a functional food because its seeds contain higher amounts of polyphenols (e.g., rutin) compared to common buckwheat. However, because of its highly bitter taste and difficulties in cultivation, the agricultural production and usage of Tartary buckwheat in food products remain limited. The nutritional and functional ingredients of Tartary buckwheat include quercetin, which causes its bitterness and is generated by rutinosidase (rutin-degrading enzyme). A nonbitter Tartary buckwheat variety with trace levels of rutinosidase has recently been developed. Despite such research, there is still a lack of agronomic information on Tartary buckwheat. Lodging can be a significant problem during its cultivation, and a lodging-resistant, semidwarf variety has been developed. This paper summarizes recent advances in our knowledge regarding the nutritional and agronomic traits of Tartary buckwheat. The information extends our understanding of the health benefits of Tartary buckwheat and the solutions to challenges in its agricultural production. Keywords: agronomic traits, nutrient function, Tartary buckwheat

The seed-setting habit of a semidwarf common buckwheat ( Fagopyrum esculentum Moench) line was evaluated in a field experiment under standardand high nitrogen levels. The ‘semidwarf line’ and ‘Kitawasesoba’were used in the present study. The main stem length of the ‘semidwarf line’ was approximately two thirds of that of the ‘Kitawasesoba’.Minimal differences were observed inthe numbers of nodes on the main stem and primary branches of the ‘semidwarf line’ and ‘Kitawasesoba’ among genotypes and nitrogen levels.No drastic decline of seed yield by the shortening of the main stem length along with the introduction of dwarfness was observed in the ‘semidwarf line’ compared with ‘Kitawasesoba’. The number of flower clusters per plant of the ‘semidwarf line’ in the high nitrogen plot tended to be greater than that of the ‘semidwarf line’ in the standard nitrogen plot and ‘Kitawasesoba’ in bothnitrogen plots. This increase inflower clusters occurred on branches. The number of seeds of the ‘semidwarf line’ in the standard nitrogen plot was considerably lower than that of the ‘Kitawasesoba’ in both nitrogen plots.Similar tendencies were observed in the weights of seeds. The decline of seed number and weight of the ‘semidwarf line’ in the standard nitrogen plot was mainly observed in branches. From these results, it was found that the seed-set in the ‘semidwarf line’ can be improved by nitrogen fertilizer application. Furthermore, seed production on branches may play an important role in the high-yielding ability of semidwarf common buckwheat.

モンゴルにおいて，施肥を行わない粗放的農地の拡大から土壌保全のための技術が求められている。そこでモンゴルの半乾燥地において，2010年から2013年にわたり行った，家畜糞を自給可能な肥料として使用する圃場試験について報告する。最初の圃場試験（Experiment-1）では，モンゴルで伝統的な粗放的農地管理下において，2010年から2012年にわたり，バレイショ，ライ麦，飼料用カブを家畜糞堆肥（ヤギおよび羊の糞）40 Mg ha－1y－1または化学肥料（90 kg ha－1y－1 of N, P2O5, and K2O）を使用して3年間栽培した。次の圃場試験（Experiment-2）では，より集約的に雑草除去を行う条件下で2013年に家畜糞堆肥を2ヶ月熟成したもの（2m-compost）および2年間熟成した堆肥（2y-compost）をそれぞれ20, 40, 60 Mg ha－1施用し，バレイショを栽培した。Experiment-1の結果，3年間の栽培において，土壌中可給態窒素量および収量は，ともに家畜糞堆肥において多く，化学肥料の施与効果は全く認められなかった。化学肥料の効果が認められなかった理由として，生育期間中の降水量の不足及び粗放的管理下における雑草によるストレスが考えられる。しかしながらExperiment-2の結果として，雑草除去を行う条件下では2y-compost施用下において無施肥区に比べ有意な収量増加が認められた。これは2y-compostの熟成期間が長くそれにより窒素含量も高かったことによると見られた。これらの結果から，モンゴルにおいて伝統的な粗放的農地管理下では，化学肥料，有機肥料の使用はともに収量向上に効果的でなく，一方で堆肥施肥は集約的な農地管理下で有効に収量を向上させうることが示された。, In Mongolia, the rapid increase of extensive cropping areas without fertilization has created a serious need for land conservation technology. This paper describes the field study we conducted in a semi-arid region of Mongolia from 2010 to 2013 in which we used animal composts as a self-support fertilizer for two field experiments. In the first field experiment (Experiment-1), from 2010 to 2012, potato, rye, pea and turnip crops were cultivated in the compost plot with the application of animal compost (3-month matured dung of sheep and goats) of 40 Mg ha－1y－1, and in the NPK plot with the application of chemical fertilizer (90 kg ha－1y－1 of N, P2O5, and K2O) under traditional extensive land management without weed control. In the second field experiment (Experiment-2) in 2013, the effects of composts with different application amounts and maturing time were studied under weed control. The composts with a 2-year maturing time (2y-compost) and a 2-month maturing time (2m-compost) were applied in amounts of 20, 40, and 60 Mg ha－1 for potato and wheat. From the results of Experiment-1, during three years, we saw that the soil available-N values and crop yields tended to be higher for the compost plot and there was no effect from chemical fertilizer on crop yields. The low efficiency of chemical fertilizer might be due to insufficient precipitation and severe weed stress under extensive land management. However, the use of animal compost had an apparent positive effect in Experiment-2 with controlling the weed effect. We observed significantly higher yields for application of the 2y-compost compared to the control. The long maturing time compost was more effective to increase crop yields due to its higher N content. These results showed that the use of both chemical and organic fertilizer was not effective to increase crop production under the extensive cropping system traditionally used in Mongolia. Also it was shown that the compost application increases crop yield under intensive land management.

Phosphorus (P) fertilizer can potentially serve as a source for Se accumulation in croplands. Furthermore, it has been reported that the addition of P fertilizer to soil may enhance Se availability. Japanese agricultural soils are typically enriched in P as a result of long-term, excessive P fertilization. Therefore, we conducted a three-year field experiment in order to evaluate the effect of P fertilization on the Se content of soils and crops. Potato, wheat and barley were cultivated with and without P fertilization at two field sites in Hokkaido (northern Japan) with different levels of historical P accumulation. The first field site consisted of an Andosol soil with low available P and the second site, a Cambisol soil with high available P. The three years of continuous P fertilization over the course of the experiment did not result in a significant increase in the Se content of soils or plants. The Se content of soils and plants, however, was higher in soil samples from the Cambisol field site than from the Andosol field site, and total soil Se was significantly correlated with available soil P. Soluble soil Se and the soil-plant transfer factor for Se were not affected by P fertilization. Thus, we concluded that the higher plant Se content at the Cambisol field site was primarily due to the higher levels of accumulated Se in the soil at the site and that historical excess P fertilization typical of agricultural soils in Japan contributes to increased Se uptake by crops.

A novel system for monitoring methane emission from a flooded paddy field was developed in order to quantify the greenhouse gas emission in near-natural conditions. A paddy field planted with rice was covered by a semi-open vinyl tunnel (1.8 × 10 × 2.5 m), and the methane concentrations inside and outside the tunnel were measured continuously from the booting stage to the ripening stage (August–September) using a methane gas detector. Methane emission rates were calculated on an hourly basis from the differences between the internal and external methane concentrations and the natural diffusion rates determined using a tracer gas method. The results indicated that the paddy field emitted 0.41–1.32 g methane m−2 day−1 during the two growth stages. The vinyl tunnel had no adverse effect on the growth and yield of rice plants inside. Despite the disadvantage of non-accurate estimation under windy conditions, the technique is considered to be of potential value for evaluating methane emissions from a flooded paddy field.

The response spectrum for green light induced-acceleration of heading in wheat cv. Norin 61 was investigated using narrow-bandwidth (10 nm) green light within the range of 520–550 nm. Heading was observed from approximately 30 days after emergence. The earliest heading was observed at 540 nm, which suggests the presence of a green light photoreceptor different from hitherto known photoreceptors.

Soil and water contaminated with arsenic (As) pose a major environmental and human health problem in Bangladesh. Phytoremediation, a plant-based technology, may provide an economically viable solution for remediating the As-polluted sites. The use of indigenous plants with a high tolerance and accumulation capacity for As may be a very convenient approach for phytoremediation. To assess the potential of native plant species for phytoremediation, plant and soil samples were collected from four As-contaminated (groundwater) districts in Bangladesh. The main criteria used for selecting plants for phytoremediation were high bioconcentration factors (BCFs) and translocation factors (TFs) of As. From the results of a screening of 49 plant species belonging to 29 families, only one species of fern (Dryopteris filix-mas), three herbs (Blumea lacera, Mikania cordata, and Ageratum conyzoides), and two shrubs (Clerodendrum trichotomum and Ricinus communis) were found to be suitable for phytoremediation. Arsenic bioconcentration and translocation factors > 1 suggest that these plants are As-tolerant accumulators with potential use in phytoextraction. Three floating plants (Eichhornia crassipes, Spirodela polyrhiza, and Azolla pinnata) and a common wetland weed (Monochoria vaginalis) also showed high BCF and TF values; therefore, these plants may be promising candidates for cleaningup As-contaminated surface water and wetland areas. The BCF of Oryza sativa, obtained from As-contaminated districts was > 1, which highlights possible food-chain transfer issues for As-contaminated areas in Bangladesh.

Wheat (Triticum aestivum L. cv. Norin 61) plants were grown under five different photon flux densities obtained by modulating the number of green light-emitting diodes (LEDs) under white fluorescent lamps. The experiment was conducted under continuous irradiation at a constant temperature of 20°C to clarify the developmental responses of wheat to the fluence rate of green light. The higher the photon flux density of green light, the shorter the number of days from emergence to heading. The earliest heading was observed in the plants grown under 496 green LEDs, 32.0 days after emergence. A significant logarithmic function could fit the relationship between the fluence rate of green light and developmental rate. In this report, principal component analysis (PCA) was adopted to analyze the confounding of green light versus photosynthetic photon flux density (PPFD) with 17 developmental and morphological traits. The eigenvalues explained were 5.64, 3.20, and 2.61, respectively, for the first, second and third principal components (PCs). The first PC was assumed as the factor related to the isometric growth, and the third PC was assumed as the factor related to the developmental rate and culm elongation. Therefore, it was supposed that the first and third PCs were affected by the PPFD and the photon flux density of green light, respectively. The results suggested that the fluence rate of green light affects the development of wheat as a signal source. Furthermore, the development of wheat was promoted by the green light independent of PPFD.

The developmental rate of wheat was investigated under continuous light of eight different qualities (in eight plots) obtained by combining three out of four different kinds of fluorescent lamps (white, blue, purplish red and ultraviolet-A) at a constant temperature of 20°C. A Japanese spring wheat var. Norin 61 and a winter wheat var. Shun-yo were used. The number of days from seeding to heading varied extensively with the variety and the light quality. The first heading was observed in the plot under three white fluorescent lamps (W + W + W) at 37 and 81 days after seeding in Norin 61 and Shun-yo, respectively. The developmental rate in both cultivars was significantly correlated with the ratio of energy in 500-550 nm range (green light) and 600-700 nm range (red light) to that in the whole spectral range (250-1,000 nm). These results suggest that green and red lights play important roles in the regulation of the developmental rate independent of photoperiodism and vernalization.

Studies regarding the developmental stage of common buckwheat (Fagopyrum esculentum Moench) have not been adequately performed despite its importance in studying the yield-determining process. In addition, the difference between common buckwheat and Tartary buckwheat (F. tataricum (L.) Gaertn.) is still unclear. In the present study, the differentiation and growth of the growing point until the stage of flower bud appearance were evaluated in the common buckwheat variety ‘Kitawasesoba’ and the Tartary buckwheat variety ‘Manten-Kirari’, which are the leading buckwheat varieties in Hokkaido, Japan. With some exceptions, the developmental stages of ‘Kitawasesoba’ and ‘Manten-Kirari’ can be distinguished. Thus, leaf primordia, axillary flower bud, and terminal flower bud differentiations and growths were observed. Both the common and Tartary buckwheat varieties did not exhibit large differences in the morphology of the growing point. However, the two varieties showed differences in the rates of differentiation and growth.Received: April 11, 2019; accepted: June 8, 2019Keywords: common buckwheat, developmental stage, growing point, Hokkaido, Tartary buckwheat

北海道網走地域は北日本の最も重要な農業地帯の1つである。長期にわたる施肥によって同地域のほとんどの農耕地土壌には過剰に蓄積した可給態リン,カリウムが認められる。さらに,この地域では3年間に1回,およそ30Mgha^-^1の堆肥の施用によって,リンとカリウムが約450kg P_2O_5ha^-^1,780kg K_2Oha^-^1程度投入されている。この蓄積したリンおよびカリウムを利用し,リンとカリウムの減肥が可能であるかどうか評価するため,圃場試験を行った。テンサイ,バレイショ,コムギおよびオオムギを用いたこの地域内の典型的な輪作体系の中で栽培した。その際施肥条件として,i)慣行NPK施肥,ii)リン半量施肥;iii)無リン施肥;iv)無リン,無カリ施肥をそれぞれ設けた。試験圃場として,黒ボク土圃場2圃場(Urashibetsu A, B),灰色台地土圃場2圃場(Yasaka A, B)の4圃場を使用した。試験開始前(2008年)に堆肥30Mgha^-^1をUrashibetsu AおよびYasaka A圃場に施用した。Urashibetsu BおよびYasaka B圃場については,2007年と2010年に同様に堆肥30Mgha^-^1が施用されており,特にUrashibetsu B圃場には,2010年に緑肥としてエンバクが栽培され,鋤きこまれている。これら圃場において作物の収量,土壌中可給態リン酸,交換性カリウム含量及び形態別リン酸(Al 型P,Fe型P,Ca型P)を測定した。結果として,3年間の試験においてリンおよびカリウム無施肥による収量への影響はほとんど認められなかった。堆肥の施用により,3年間のリン,カリウム無施肥処理においても土壌の可給態リン酸,交換性カリウム含量の減少は認められなかった。堆肥の施用はまた,Urashibetsu AおよびYasaka A圃場においてCa型Pの増加および Fe型Pの減少をもたらした。以上の結果は堆肥の施用が有機体リンの供給源としてのみならず本来不可給態であるFe型Pの可給化によって土壌の可給態リンを増加させたことを示唆した。これらの結果から,リンおよびカリウムの減肥あるいは無施肥は堆肥の施用後に行うことが望ましいと考えられた。, The Abashiri area in Hokkaido Prefecture is one of the most important agricultural areas in northern Japan. Due to long-term fertilization, most of the agricultural soil in this area has highly accumulated available P and K. In addition to this, typically about 450kg P_2O_5ha^-^1 and 780kg K_2Oha^-^1 have been applied with 30Mgha^-^1 of animal manure every three years. In order to assess the possibility of decreased P and K fertilization using this accumulated P and K, we evaluated the effects of three years of continuous low or no P and K fertilization on crop productivity by a field experiment. From 2009 to 2011, sugar beet, potato, wheat and barley were cultivated using the major crop rotation system in this area. Four fertilization methods were used: i) Conventional NPK application, ii) Half P fertilization; iii) No P fertilization; and iv) No P and no K fertilization. Two Andosol fields (Urashibetsu A, B) and two Cambisol fields (Yasaka A, B) were used for this study. 30Mgha^-^1 of manure was applied to Urashibetsu A and Yasaka A field before the experiment. For Urashibetsu B and Yasaka B field, the same amount of manure was applied in 2007 and 2010, respectively. Especially in Urashibetsu B field, in 2010, oat was cultivated as green manure and plowed back into the field. The crop yield, soil available P and exchangeable K amounts, soil P fractions (Al bound P, Fe bound P, Ca bound P) were measured. As a result, almost no significant effects of P/K fertilization on crop yield were observed during three years. Due to manure application, soil available P and exchangeable K amount did not decrease because of the three years of no P and no K application. Manure application for Urashibetsu A and Yasaka A fields also increased Ca bound P fraction and decreased Fe bound P fraction. These results suggested that manure application increased soil P availability not only as an organic P source but also as a contributor to Fe bound P utilization. From these results, we considered that decreased or no P/K fertilization method should be started the next year after manure application in Abashiri area.