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An important breeding issue in buckwheat is to increase its resistance to lodging, which can result in the loss of yield and quality of buckwheat foods. We developed the semidwarf buckwheat 'Kyukei 50', which has a short plant height and a strong lodging resistance. The internode length of 'Kyukei 50' was shorter than that of the summer‐sown standard variety 'HITACHIAKISOBA'. Progeny analysis revealed that the semidwarf trait was dominated by at least one recessive gene. Compared with 'HITACHIAKISOBA', in 'Kyukei 50', the time of maturation was earlier, and the pre‐harvest sprouting resistance was the same, indicating that 'Kyukei 50' is suitable for sowing in both spring and summer. 'Kyukei 50' exhibits the 'green flower type' shattering resistance trait and, therefore, has a thick pedicel; breaking tensile strength is approximately two‐fold stronger than that of 'HITACHIAKISOBA'. The yield of 'Kyukei 50' is the same as that of 'HITACHIAKISOBA'. In addition, the lowest seed height of 'Kyukei 50' was >17 cm. These results indicate that the 'Kyukei 50' is a promising breeding line for lodging resistance and loss of harvesting machinery. [ABSTRACT FROM AUTHOR]

To evaluate the potential of perennial buckwheat (Fagopyrum cymosum; FC) as a food source, rutin concentration was investigated. FC contains more than 1% (w/w) rutin and 0.03% quercetin in the leaves, flowers, and seeds. In particular, rutin and quercetin concentrations were high in plant seeds. Therefore, FC is useful as a rutin- and quercetin-rich material. In contrast, the FC seed contained a large amount of rutinosidase. Purified rutinosidase in a homogenous mixture consisted of only one isozyme with M.W. of 58.4 KD and low Km for rutin (0.367 mM). The rutin concentration in the FC dough decreased to almost zero, 10 min after the addition of water. Parallel to the decrease in rutin, quercetin was increased, and strong bitterness was generated, whereas steam-heated flour in which rutinosidase was inactivated did not have rutin hydrolysis and bitterness. These results indicate that rutinosidase is a major cause of rutin hydrolysis and bitterness. The in vitro rutinosidase is inactivated at pH 8.0 and 65 °C. Therefore, the control of dough pH and temperature should be useful in preventing rutinosidase activity. [ABSTRACT FROM AUTHOR]

In understanding the role of root cell wall mechanisms in plant tolerance to salinity, it is important to elucidate the changes in the pectin composition and physical properties of the cell wall. Two salt-sensitive (Helan 3 and Prius β) and one salt-tolerant (R7) spinach cultivars were used to investigate the pectin polysaccharides, the characteristics of pectin, including the degree of pectin methy-lesterification, the HG:RG-I ratio, neutral side chains (galactan/arabinangalactan), and elasticity and viscosity parameters in the root elongation zone under salinity. Root growth was inhibited by salinity, whereas the root diameter was thickened in all cultivars. Salinity significantly reduced cell wall extensibility in all cultivars, and increased cell wall viscosity in Helan 3 and R7 relative to Prius β. Pectin was significantly increased under salinity stress. Cell wall viscosity was affected by pectin due to the molar proportion of uronic acid and/or pectin characteristics (HG:RG-I ratio). The molar proportion of uronic acid in pectin was reduced in Helan 3 and R7 compared with Prius β. The length and degree of pectin methy-lesterification of neutral side chains were significantly decreased in the R7 cultivar, with no significant changes in the other two cultivars. Demethylation of pectin could alter root growth and boost salt tolerance in the R7 cultivar. In this study, it is shown that cell wall pectin played important roles in regulating the root growth of Spinacia oleracea L. under salinity stress. [ABSTRACT FROM AUTHOR]

The accumulation of salts within the rhizosphere is a common phenomenon in arid and semi-arid regions where irrigation water is high in salts. A previous study established the ameliorative effect of foliarly applied 24-epibrassinolide (BR) on soybean under salinity stress. As a follow-up to that study, this work evaluated the effects of BR on the electrical conductivity of saturated soil extracts (ECses) under soybean exposed to salt stress. Three salinity levels (3.24, 6.06 and 8.63 dS/m) in a factorial combination with six frequencies of BR application—control, seedling, flowering, podding, seedling + flowering and seedling + flowering + podding—were the treatments, and the rhizospheric ECse was monitored from 3 to 10 weeks after the commencement of irrigation with saline water (WAST). The principal component analysis revealed that samples in saline BR treatments clustered together based on the BR application frequencies. There was a significant increase in ECse with increases in salinity and WAST. The frequent application of BR significantly reduced ECse to 5.07 and 4.83 dS/m relative to the control with 6.91 dS/m, respectively, at week 10. At 8.63 dS/m, the application of BR (seedling + flowering + podding) reduced ECse by 31.96% compared with the control. The underlining mechanism is a subject for further investigation. [ABSTRACT FROM AUTHOR]

The purpose was to elucidate the hypoxia tolerance mechanism of millet species by focusing on the oxygen acquisition mechanism of adventitious roots. Brachiaria ramosa, Echinochloa utilis, Eragrostis tef, and Setaria italica were used. Thirty-day old plants were hydroponically cultivated for 28 days as the control, where aeration was continued and a hypoxia treatment was applied, where nitrogen gas was flushed to reduce the oxygen concentration. From the stress susceptibility index based on plant growth rate, it was clarified that E. utilis and E. tef had higher hypoxia tolerance than B. ramosa and S. italica. Root growth rate, nitrogen concentration of leaves and stems, and sodium concentration per plant of the higher hypoxia-tolerant species did not change with hypoxia treatment. In hypoxia-susceptible millet species, the root growth rate and nitrogen concentration in the leaf and stem decreased, and the sodium concentration in the whole plant increased. The proportion of the stele area of the adventitious root of the hypoxia-tolerant millet species was smaller than that of the hypoxia-susceptible millet species, and the lysigenous aerenchyma was constitutively developed. Furthermore, root hairs were observed near the root tip in the hypoxia-tolerant millet species. In conclusion, we deduced that the hypoxia tolerance of the millet species is mainly attributable to the supply of oxygen to the root tip via the lysigenous aerenchyma along the adventitious root. Lower oxygen consumption by a smaller proportion of the stele area might be an important genetic trait. Furthermore, root hair may contribute to nutrient absorption. [ABSTRACT FROM AUTHOR]

Understanding the role of root cell walls in the mechanism of plant tolerance to salinity requires elucidation of the changes caused by salinity in the interactions between the mechanical properties of the cell walls and root growth, and between the chemical composition of the cell walls and root growth. Here, we investigated cell wall composition and extensibility of roots by growing a halophyte (Suaeda salsa) and a glycophyte (Spinacia oleracea) species under an NaCl concentration gradient. Root growth was inhibited by increased salinity in both species. However, root growth was more strongly reduced in S. oleracea than in S. salsa. Salinity reduced cell wall extensibility in S. oleracea significantly, whereas treatment with up to 200 mM NaCl increased it in S. salsa. Meanwhile, S. salsa root cell walls exhibited relatively high cell wall stiffness under 300 mM NaCl treatment, which resist wall deformation under such stress conditions. There was no decrease in pectin content with salinity treatment in the cell walls of the elongation zone of S. salsa roots. Conversely, a decrease in pectin content was noted with increasing salinity in S. oleracea, which might be due to Na+ accumulation. Cellulose content and uronic acid proportions in pectin increased with salinity in both species. Our results suggest that (1) cell wall pectin plays important roles in cell wall extension in both species under salinity, and that the salt tolerance of glycophyte S. oleracea is affected by the pectin; (2) cellulose limits root elongation under saline conditions in both species, but in halophytes, a high cell wall content and the proportion of cellulose in cell walls may be a salt tolerance mechanism that protects the stability of cell structure under salt stress; and (3) the role of the cell wall in root growth under salinity is more prominent in the glycophyte than in the halophyte. [ABSTRACT FROM AUTHOR]

One of the important breeding issues in buckwheat is to increase resistance to preharvest sprouting, which can result in the loss of yield and quality of buckwheat food, especially in spring‐sown buckwheat. The preharvest‐sprouting resistance of self‐pollinating buckwheat in the summer ecotype is very weak. Therefore, we developed a self‐pollinating breeding line IHK1, which has strong preharvest‐sprouting‐resistance traits. IHK1 was developed by cross breeding between 'Kyukei37' (a preharvest‐sprouting‐resistant outcrossing line) and IH3 (a self‐pollinating summer‐ecotype line). Progeny analysis revealed that the preharvest‐sprouting resistance trait in IHK1 was dominant. In three field trials conducted over 2 years, the maturation time of IHK1 was the same as that of 'Harunoibuki', the leading spring‐sown variety in the Kyushu region and the plant was shorter than 'Harunoibuki'. The yield of IHK1 was approximately 70%–85% of that of 'Harunoibuki' (165 kg/10 a; average of three times cultivation), whereas it was approximately 258%–333% when compared with IH3. Thus, IHK1 is a promising breeding line for self‐pollinating buckwheat, especially spring‐sown buckwheat. [ABSTRACT FROM AUTHOR]

Buckwheat has open‐flower morphology; therefore, isolation is necessary to propagate even in self‐pollinating lines. Here, we developed a self‐pollinating closed flower breeding line 'CFK1' by crossing between closed‐flowering individual and self‐pollinating breeding line. Progeny analysis suggested that the closed‐flowering trait would be dominated by double recessive gene, which we named closed‐flowering A and B (cfA and cfB). The evaluation test of outcrossing rate in the field revealed that 'CFK1' had 0% in progeny. An a histochemical investigation of flower buds morphology using scanning electron microscope revealed that the petals of 'CFK1' were tightly adhered to other petals whereas completely separated in wild type. The agronomic characteristics were evaluated by performance test. Compared to leading variety 'Shinanonatsusoba', the 'CFK1' had lower plant height, total weight, grain yield and 1‐L weight whereas higher plant height, total weight, grain yield and 1‐L weight when compared to 'IH3'. The preharvest‐sprouting resistance of 'CFK1' is slightly stronger than that of other tested buckwheat. From these results, 'CFK1' is promising self‐pollinating breeding line that is resistant for outcrossing. [ABSTRACT FROM AUTHOR]

The objectives of this study are to clarify the relative importance of sink and related factors of dry matter and water use pre-and post-heading in four millet species under severe water deficit. Panicum miliaceum, Panicum sumatrense, Setaria glauca., and S. italica were used. Water deficit (20% soil water content) was imposed from 25 d after sowing until harvest, with 40% soil water as a control. At the heading, half of the leaf area or all leaves on each plant were removed in both the control and the water deficit treatment (Source manipulation). Water deficit treatment markedly decreased the leaf water potential of all species from −2.02 MPa (S. italica) to −1.72MPa (P. miliaceum). The grain yields of water deficit treatment in S. italica, P. miliaceum, S. glauca and P. sumatrense decreased to 62, 48, 31, and 24% of the control, respectively. Four millet species were divided to dehydration-tolerant millet (S. italica and P. miliaceum) and dehydration-susceptible millet (S. glauca and P. sumatrense) by calculating drought susceptibility index. The interspecific difference in dehydration tolerance was accounted for by the number of grains per panicle and the harvest index. The source operation showed that the sink was more important than the source. In conclusion, under severe soil drying, it was considered that S. italica and P. miliaceum showed strong dehydration tolerance because they maintained the number of grains per panicle and did not reduce dry matter production and the partitioning of dry matter to the panicle after heading. Abbreviations: CLA0: all leaves were removed at heading in the control; CLA0.5: half of the leaf area per plant was removed at heading in the control; DAS: days after sowing; DLA0: all leaves were removed at heading in the dehydration treatment; DLA0.5: half of the leaf area was removed at heading in the dry treatment; DSI: drought susceptibility index; NSC: nonstructural carbohydrate; OA: osmotic adjustment; WUE: water use efficiency. [ABSTRACT FROM AUTHOR]

Seeds ofPanicum miliaceum, Panicum sumatrense, Setaria glauca,andSetaria italicawere raised in polyvinylchloride tubes filled with soil to determine interspecific differences in waterlogging tolerance and the effect of pre- and post-heading waterlogging on growth and grain yield. Four treatments were conducted including control (no-waterlogging stress during growth). Pre-heading waterlogging treatment was initiated 17 days after sowing to heading (TC). Post-heading waterlogging treatment was initiated heading till harvest (CT). Waterlogging treatment was initiated 17 days after sowing to harvesting (TT). The grain yield ofP. miliaceum, S. glauca,andS. italicadecreased 16, 18, and 4%, while that ofP. sumatrenseincreased 210% under TT treatment and this showedP. sumatrensehad most waterlogging tolerance. The grain yield was more affected under TC treatment inS. italica and P. miliaceum.However, there was not significant differences the grain yield between TC and CT treatment inP. sumatrenseandS. glauca. Total dry weight, total root dry weight, number of crown root, and the proportion of lysigenous aerenchyma ofP. sumatrensewere significantly higher than those of other millets at harvesting. Plant growth rate, total root dry weight, number of crown root, and the proportion of lysigenous aerenchyma ofP. sumatrensewere significantly higher than those of other millets at heading. These results suggest thatP. sumatrenseexhibits waterlogging tolerance by enhancing root growth characterized by a high proportion of lysigenous aerenchyma in the crown root. [ABSTRACT FROM AUTHOR]

The accidentally introduced beetle Ophraella communa was first found in 1996 in Japan and has rapidly expanded its distribution range to include regions with substantially different climates. During this range expansion and subsequent establishment in new habitats, the life history traits of O. communa have changed depending on new habitat environmental conditions. In this study, we investigated the photoperiodic response of O. communa controlling its reproductive diapause, an important trait that adjusts the life cycle to local climate and phenology of host-plants. We examined temporal changes and geographical differences in this trait. In the Tsukuba population of O. communa, the diapause incidence under conditions of 12 h light : 12 h dark ( LD 12:12), 13:11 and 14:10 did not consistently increase or decrease during 2005-2012, although it fluctuated yearly. The diapause incidence in this period, however, was lower than that in 1999 reported previously and the critical day-length inducing diapause was shortened by >1 h from 1999 to 2005. These results suggest that the photoperiodic response of O. communa shifted during this period. To examine geographical differences in this trait, we compared the Hirosaki, Morioka, Tsukuba and Koshi lines. The diapause incidence at LD 13:11 was significantly different between the O. communa lines: 86.5% in the Hirosaki line (collected in 2010) , 81.4% in Morioka (collected in 2010), 45.0% in Tsukuba (collected in 2011) and 7.1% in Koshi (collected in 2009), and was positively correlated with the latitude of the origin. These results suggest that this trait shifted, responding to the environmental conditions in the colonized regions. [ABSTRACT FROM AUTHOR]

This study was carried out in the natural herbaceous grassland of Mt. Aso, which had been almost completely grazed, and which is subjected to routine grassland burning every spring (February or March) to conserve Shijimiaeoides divinus asonis ( Matsumura, 1929). We clarify that ants protect the larvae of this butterfly and evaluate the effects of grazing intensity on the attendant ant population. The results obtained are summarized as follows: (i) Five species of attendant ant were identified, with the dominant species being Formica japonica ( Motschulsky, 1866) and Camponotus japonicus ( Mayr, 1866) . (ii) The number of attendant ants decreased at night time; however, only one or two ants attended the larva until the following morning. (iii) Ten species of insect excluding ants and three species of spiders that approached the larva were recorded on the larval host-plant. Formica japonica and C. japonicus fought off most newcomers of other insects including the natural enemies of these butterfly larvae. (iv) The number of ants in this butterfly habitat under regular grazing intensity was significantly higher than during low grazing intensity and non-grazing periods. (v) A positive correlation was found between the number of attendant ants and the number of butterfly larvae on the host-plant. We concluded that the interaction between this butterfly and attendant ants is one of facultative mutualism because the attendant ants protect the butterfly larva. Therefore, the numbers of this butterfly species may decrease if the number of attendant ants decreases due to the cessation of pasturage. [ABSTRACT FROM AUTHOR]