Japanese Journal of Crop Science
Online ISSN : 1349-0990
Print ISSN : 0011-1848
ISSN-L : 0011-1848
Volume 76, Issue 2
Displaying 1-23 of 23 articles from this issue
Regular Paper
Agronomy
  • Yukitsugu Takahashi, Ken-ichi Oshima, Takeo Kanzawa, Tomohiko Yoshida
    2007 Volume 76 Issue 2 Pages 171-180
    Published: 2007
    Released on J-STAGE: June 06, 2007
    JOURNAL FREE ACCESS
    We studied the possibility of introducing the single fertilizer application in an area of paddy rice culture by early planting and normal season culture in Gunma prefecture. The fertilizer was applied exclusively only to the nursery box to save labor. The seedlings were grown in the condition of pool raising, which is the standard method in Gunma prefecture. The commercialized fertilizer named "Naebako-makase" was used and a field experiment was conducted for 4 years. We found that the maximum of seedling-rearing period was 20 days due to spindly growth of seedlings by excessive dissolution of fertilizer, and injury by a high fertilizer concentration appeared sometimes after transplanting to the field. However, over-3cm-depth-flooding reduced the injury, and later these problems were almost solved by improving the fertilizer. Growth after rooting showed a pattern typical for that caused by the conventional controlled availability fertilizer. Early growth was slightly reduced and stem number was decreased. However, the percentage of ripened grains and productive stems was increased. The application of fertilizer with 34-40%-reduced nitrogen resulted in equal or higher yield and quality than in the standard fertilizer application. Therefore, we considered that this method could be introduced to the area of early planting and normal season culture in Gunma prefecture.
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  • Kazuhiro Watanabe, Takao Niino, Tohru Murayama, Masami Nanzyo
    2007 Volume 76 Issue 2 Pages 181-188
    Published: 2007
    Released on J-STAGE: June 06, 2007
    JOURNAL FREE ACCESS
    In order to apply “pre-transplanting phosphorus application” (PTPA) to the lowland rice cultivation, we examined the effects of immersing the seedlings in potassium phosphate solution at different concentrations on the early growth and mineral absorption after transplanting using 15 varieties of rice. PTPA increased the total dry weight, leaf area and tillering number four weeks after transplanting. It increased the leaf area ratio (LAR) at two weeks after transplanting, by increasing allocation of assimilate to leaf blades, and raised the net assimilation rate (NAR) during the following two weeks (2-4 weeks). PTPA was supposed to shorten the rooting period, because it increased tillering number during the first two weeks after transplanting. Phosphorus (P) content per dry weight in each plant part two weeks after transplanting with increasing P concentration in the solution, but a varietal difference was observed in the extent of increase in the P content; it was high in the varieties that were bred in a tropical to subtropical region, such as Indica varieties. Total P content per plant was still increased by PTPA for at least four weeks after transplanting. These results suggested the possibility of lowland rice cultivation with reduced amount of phosphorus application by applying PTPA.
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  • Tatsuya Inamura, Akane Yoshikawa, Kengo Matsumoto, Sachiko Ikenaga, Hi ...
    2007 Volume 76 Issue 2 Pages 189-197
    Published: 2007
    Released on J-STAGE: June 06, 2007
    JOURNAL FREE ACCESS
    Sources of the variation of wheat yield in paddy-upland rotational fields (rice-wheat-soybean) were examined during the wheat seasons from 2002 through 2004 to evaluate the possibility of the variable rate management that implements the site-specific input of agricultural materials, e.g. fertilizer and seed, in proportion to the variation of these sources in the field for maximum yield. The number of panicles was the largest source of variation contributing to wheat yield among the three yield components (number of panicles, thousand-grain weight and number of ripened grain per panicle). This result proposed the number of panicles as the criterion of variable rate management for maximizing the yield. The number of panicles was effected by the seeding rate via the number of establishment, the amount of nitrogen accumulated in aboveground biomass at spikelet-initiation stage and the number of stems, and in addition, it seemed to be effected by the soil moisture percentage at seeding via the emergence depth. Therefore, the proper management of variable rate seeding in proportion to the soil moisture percentage on dried soil basis at seeding in the field may be able to control the number of panicles in the field to bring the adequate average yield. This variable rate management may control 42.7% of the controllable proportion to total variation of wheat yield in the field.
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  • Kohsuke Hamaya, Satomi Yahashi, Kaori Nonokawa, Hiroki Yahagi, Katsuno ...
    2007 Volume 76 Issue 2 Pages 198-203
    Published: 2007
    Released on J-STAGE: June 06, 2007
    JOURNAL FREE ACCESS
    Supernodulating soybean cultivar "Sakukei 4" has a high nitrogen fixing activity. The yield of soybean is reduced under high groundwater-level conditions, but the reduction might be mitigated by using such cultivars. In this study, we investigated the yield of Sakukei 4 treated with a high groundwater level at different times, especially at the time of flowering and seed set. The cultivars Enrei and Sakukei 4 differed in the growth period during which a high ground water level treatment affected the number of flowers and seed weight. In both cultivars, the number of flowers and seed weight were decreased by the high ground water level treatment applied during the floral differentiation stage. The high ground water level treatment applied during the flowering time did not promote the falling of flowers and pods in Enrei, but promoted it in Sakukei 4. The main reason for the decrease in yield of Sakukei 4 was the falling of flowers and pods in high-order racemes and the decrease in the pod number. In this study, the use of supernodulating soybean cultivar Sakukei 4 did not mitigate the yield reduction under the high ground water level conditions at the time of flowering.
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  • Kuniyuki Saitoh, Kazuo Hirata, Youko Kashiwagi
    2007 Volume 76 Issue 2 Pages 204-211
    Published: 2007
    Released on J-STAGE: June 06, 2007
    JOURNAL FREE ACCESS
    To elucidate the effect of planting patterns on yield performance of soybean, we cultivated early cv. ‘Enrei’ with 80 and 30 cm row-spacing, and 11.1 and 22.2 plants m-2 in 2001 and 2002. The number of nodes on main stem, racemes with compound leaves and total number of nodes, were larger in dense planting than in normal planting in both years. The number of branches, nodes on branches, racemes with compound leaves, and total number of nodes per m2 were larger in narrow-row planting than in wide-row planting. The length of main stem was longer in dense planting than in normal, and in wide-row planting than in narrow-row planting. The weight, diameter and cross section area of stem were longer(greater)in normal than in dense planting and in narrow-row than in wide-row planting. Seed yield was higher in 2001 than in 2002, in dense planting than in normal planting, and in narrow-row than in wide-row planting. The highest seed yield, 668g m-2, was obtained in 2001 with dense and narrow-row planting. The yield was mainly determined by the pod number in 2001, and by both pod number and seed size in 2002. In dense planting, a large proportion of pods were occupied by those on the main stem and racemes with compound leaves, and in narrow-row planting, a large proportion of pods were occupied by those on branches and racemes with compound leaves. Seed yield was closely correlated with pod number on the racemes with compound leaves, especially in 2001. In narrow-row planting, the upper layer of canopy had a large leaf area but it had low light extinction coefficients, and the canopy exhibited good light intercepting characteristics. Although the solar radiation in canopy differed between the spaces on the furrows and ridges in wide-row planting, the radiation in canopy was uniform in narrow-row planting. The yield in narrow-row planting with dense planting was higher than that in wide-row planting. This is due to the reduction of competitions with neighbor plants resulting from the suppression of elongation growth and increased development of branches. It was also due to the increased development of the racemes with compound leaves and increased pod number resulting from the efficient use of solar radiation in the upper layer of the canopy. Improvement of lodging tolerance and establishment of weed control at earlier stage is needed for the narrow-row and dense planting of soybean.
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  • Yukihiro Hamada, Ichiro Shaku, Yasuhiko Sawada, Hajime Kojima
    2007 Volume 76 Issue 2 Pages 212-218
    Published: 2007
    Released on J-STAGE: June 06, 2007
    JOURNAL FREE ACCESS
    Soybean yield in Aichi prefecture, Japan, has been low and unstable due to excess soil moisture during seeding time. We have been developing the production technology including no-till culture to reduce such problems. This study aimed to identify the causes for the submergence damage in no-till culture. In the field experiment, the rainfall on the following day of seeding substantially damaged the seedling emergence, and the damage was more severe in hollowed and portions more distant from the drainage in the field. In the pot experiments under no-till conditions, seedling emergence was damaged by 24-h flooding treatment on the seeding day and 4 days after seeding, while under tilling conditions, the treatment on 3 and 5 days after seeding also damaged the emergence. Experiments on water absorption of the germinating seeds suggested that the damage by the flooding on the seeding day in the pot experiment was caused by the destruction of seed structure due to rapid water absorption. On the other hand, the damage by the flooding 3 to 5 days after seeding may be caused by oxygen deficiency because the seedling emergence force derived from elongating hypocotyl peaked at 5 days after seeding when the seedling may require oxygen most. It is concluded that the reduction or avoidance of the submergence damage during the first 5 days is the key to stable no-till seeding during rainy season in the region.
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  • Yukihiro Hamada, Ichiro Shaku, Yasuhiko Sawada, Hajime Kojima
    2007 Volume 76 Issue 2 Pages 219-225
    Published: 2007
    Released on J-STAGE: June 06, 2007
    JOURNAL FREE ACCESS
    The seeding time of soybean inevitably tends to fall in the rainy season especially in Aichi prefecture, Japan. Soybean plants grown with no-till culture often suffer from submergence damage due to rain water stagnated in the rugged field created by farming operation for the previous cropping. The reduction or avoidance of the submergence during the first 5 days after seeding has been found to be the key to stabilize the no-till soybean culture in this region. Therefore we evaluated the impact of a simple drainage system we developed on the seedling emergence and growth, which consists of open ditches parallel with seeding furrows, mole drains crossed with ditches at right angles and cracks under seeding furrow made by the disk colter attached to the Aichi-type no-till seeder. The results showed that this system effectively drained the stagnant water in the vicinity of seeds, and thus the submergence damage was minimized even when there was a heavy rain right after seeding except in the fields where the water permeability was extremely low or the groundwater level was consistently high. The no-till seeding with the Aichi seeder could be a practically useful technology that enables efficient seeding during the rainy season for stabilized seedling emergence when combined with this simple drainage system in the field not extremely low in water permeability.
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Quality and Processing
  • Kengo Ogiuchi
    2007 Volume 76 Issue 2 Pages 226-231
    Published: 2007
    Released on J-STAGE: June 06, 2007
    JOURNAL FREE ACCESS
    The processing qualities (amylogram, milling, 60% extraction flour, bread-making and noodle-making characteristics) of winter wheat seeded from mid-December to late December -- winter-seeding cultivation (W.S.) -- were compared with those of winter wheat seeded in early October -- standard autumn-seeding cultivation (S.A.S.). The appearance quality of the grain and maximum viscosity on the amylogram in W.S. were nearly the same as those in S.A.S.. The winter wheat in W.S. matured 3—5 days later than that in S.A.S., but can be harvested in early July before the rainy season. Thus, the harmful effect of much rain on grain quality due to the delay of maturity was avoided by W.S. In W.S., the thousand grain weight was lighter, but the bulk density was the same or higher, and the milling quality, flour color and farinogram characteristics were nearly the same as in S.A.S.. In W.S., the ash content of the grain was lower, and the protein content of the grain was the same or higher than those in S.A.S.. No significant difference was observed between W.S. and S.A.S. in the bread-making and noodle-making characteristics, but in cultivar “Yukichikara”, the bread volume and total overall characteristics in W.S. were higher than those in S.A.S.. We considered that the protein content of the grain in W.S. was increased by the amount of fertilizer, which was larger in W.S. than in S.A.S., resulting in a higher bread-making quality. Although the growing phase in W.S. was different from that in S.A.S., the appearance quality of the grain and the processing quality in W.S. were the same or better than those in S.A.S..
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  • Atsushi Ogawa, Satoru Taguchi, Choji Kawashima
    2007 Volume 76 Issue 2 Pages 232-237
    Published: 2007
    Released on J-STAGE: June 06, 2007
    JOURNAL FREE ACCESS
    In recent years, the number of patients on dialysis due to kidney failure is tending to increase in Japan. These patients must restrict potassium intake, because they cannot excrete the potassium ion adequately. The objective of this study was to establish a method of cultivating spinach with a low potassium content while maintaining normal plant growth. Spinach plants were grown hydroponically with reduced potassium application throughout the growth period or with no potassium applications during the last half of the growth period. There were no significant differences in fresh weight at harvest between controls and plants in the potassium-limited treatments. The potassium content per fresh weight was reduced as much as 32% by the former treatment and 79% by the latter treatment compared with the controls. These results suggest that it is possible to produce low-potassium spinach maintaining the normal plant growth. Sodium and magnesium content increased with the decrease of potassium content, showing that they had a role in the control of osmotic pressure in the absence of normal potassium.
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Genetic Resources and Evaluation
  • Hiroichi Sato, Tomohiko Yoshida
    2007 Volume 76 Issue 2 Pages 238-244
    Published: 2007
    Released on J-STAGE: June 06, 2007
    JOURNAL FREE ACCESS
    The pedigree of breeding lines of rice in Fukushima Agricultural Experiment Station (breeding lines) and cultivars (comparative varieties) in Fukushima Prefecture was analyzed. The ancestors making the greatest genetic contribution to breeding lines were Asahi followed by Aikoku, Oba, Kamenoo, Kiryoyoshi, Joshu and Kyotoshinasahi, in this order. It was recognized that the breeding lines showed a high coefficient of parentage to Asahi, Oba and Kamenoo, differing from the other breeding lines reported to date. In breeding lines, the parentage to Koshihikari and Kamenoo showed a significant negative correlation with the grain quality and the coefficient of parentage to Asahi showed a significant positive correlation with the grain quality. The coefficient of parentage to Koshihikari and Norin 22 showed a significant positive correlation with eating quality, but that of the breeding lines did not. It was considered that new parental materials were necessary to breed lines with high eating quality, because all of the breeding lines showed a high coefficient of parentage to Koshihikari. Based on the genetic background defined by this pedigree analysis, the parents for crossing may be selected more rationally.
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  • Masakata Hirayama, Hiroshi Nemoto, Hideo Hirasawa
    2007 Volume 76 Issue 2 Pages 245-252
    Published: 2007
    Released on J-STAGE: June 06, 2007
    JOURNAL FREE ACCESS
    The relationship between drought resistance and deep root system was examined using eight Japanese upland rice and one lowland rice variety with medium to late maturing cultivated in the upland field for six cropping seasons. The number and thickness of roots at each depth were observed by eye by the excavation method in 1994 to 1996. The root length and weight at each soil depth were measured by the monolith method in 1996, and by the core sampling method in 1998, 2001 and 2002. A varietal difference was observed in root growth through six cropping seasons. In particular, a marked difference was observed in root density in the soil layer deeper than 30 cm from soil surface. Drought resistant variety, Yumenohatamochi stably showed a high root density in a deeper soil layer. On the other hand, root density of a susceptible variety, Mizuhatamochi, was low. Therefore, it was concluded that root growth in a deeper soil layer had a close relationship with drought resistance. Yumenohatamochi, Rikuto-norin-mochi 26 and Mizuhatamochi were selected as standard varieties of 'deep','slightly deep' and 'shallow' rooting, respectively. The observed root density in the deep soil layer examined by the monolith method and the core sampling method showed a significant positive relationship with that examined by the excavation method. Therefore, the core sampling method was considered to be a practicable and reliable collection method of roots in drought resistance breeding of upland rice.
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  • —Effects of Planting Density—
    Tomiya Maekawa, Makie Kokubun
    2007 Volume 76 Issue 2 Pages 253-261
    Published: 2007
    Released on J-STAGE: June 06, 2007
    JOURNAL FREE ACCESS
    The supernodulating soybean cultivar “Sakukei 4” is considered to be potentially high-yielding because of its superior capability of nitrogen fixation and photosynthesis. Despite these desirable traits, Sakukei 4 was found to exhibit inferior initial growth under conventional culture conditions. To explore the method of high-yielding cultivation of this cultivar in Miyagi, we conducted two experiments (Exp.1, 2) at two locations in different years (Naruko · 2003 and Sendai · 2004). Sakukei 4 was grown at two planting densities (standard and dense planting densities), and its growth and yield were compared with its parental normally-nodulating cultivar “Enrei” and non-nodulating genotype “En1282”. In Exp.1 (Naruko · 2003), dense planting increased significantly the growth (dry weight) and leaf area index (LAI), irrespective of cultivars, but it significantly increased yield only in Sakukei 4. In Exp.2 (Sendai · 2004), dense planting increased significantly the growth and LAI of Sakukei 4, but it failed to increase the yield of any genotype examined. The yield of the three genotypes tested in both experiments tended to be Enrei > Sakukei 4 > En1282 in this order, reflecting the difference of dry weight at flowering and seed-filling stages. The number of nodes, pods and seeds, and seed-set percentage of main stem were markedly increased by dense planting in both Sakukei 4 and Enrei, but the number of branches was increased only in Enrei. In conclusion, increasing planting rate was effective for increasing the yield in Sakukei 4 to some extent, but the yield of Sakukei 4 failed to exceed that of Enrei. The growth of branches at dense planting rate in Sakukei 4 was inferior to that in Enrei, suggesting that cultivation conditions to enhance yield components on the main stem might be effective for the high-yielding cultivation of Sakukei 4.
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Crop Morphology
  • Fumitaka Shiotsu, Jian Liu, Masanori Toyota, Akihito Kusutani
    2007 Volume 76 Issue 2 Pages 262-272
    Published: 2007
    Released on J-STAGE: June 06, 2007
    JOURNAL FREE ACCESS
    The influence of the size of vascular bundle and carbohydrate translocation on the ripening ability of rice were investigated with high-yielding varieties bred in Asian countries and Japanese varieties. The percentages of ripened grains in whole panicle (R), on primary rachis-branch (R1) and on secondary rachis-branch (R2) were lower in high-yielding varieties. The relations among the amount of carbohydrates increased during the period from heading to maturing per paddy (ΔC/N), that of carbohydrates in stem during the same period per paddy (T/N), and the percentage of ripened grains, were analyzed. T/N in high-yielding varieties showed a significant positive correlation with R, R1 and R2, and also with the total area of large vascular bundles per paddy (Vb/N). These significant correlations, however, were not observed in Japanese varieties. Moreover, multiple regression analysis on the percentage of ripened grains indicated that Vb/N strongly contributed to R2 in high-yielding varieties. These results showed that cultivars with a larger Vb/N have a higher T/N. Such cultivars may have a higher R mainly due to the increased R2. However, it was suggested that the size of vascular bundle did not directly affect the ripening ability in Japanese varieties because other factors also influenced the translocation of carbohydrate.
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Crop Physiology and Cell Biology
  • Yoshiaki Watanabe, Shigenori Miura, Tomoyuki Yukawa, Shigehito Takenak ...
    2007 Volume 76 Issue 2 Pages 273-278
    Published: 2007
    Released on J-STAGE: June 06, 2007
    JOURNAL FREE ACCESS
    The effects of duration and light conditions of cold acclimation (2°C,12h photoperiod) and environmental condition after cold acclimation on the resistance to Pythium snow rot in barley were studied. The resistance to the spread of symptoms was measured by legion length extended from inoculation point inoculated with a Pythium snow rot pathogen, P. paddicum on the leaf blade. The duration of cold acclimation significantly affected the resistance to snow rot. The significant increase in the resistance was observed after 7 days of cold acclimation treatment. The resistance was further increased by 14 days of cold acclimation, but further prolongation of the cold acclimation period from 14 to 28 days had no effect. During 7-day cold acclimation period, light was necessary to increase the resistance, although light intensity and color had no influence. The resistance attained by the 7-day cold acclimation was nullified by a subsequent exposure to 15°C in darkness for 14 days or cold and dark condition (0.5°C, darkness for 28 days).
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Modelling, Information and Environment
  • Eiji Kanda, Yoichi Torigoe, Tetsuhisa Miwa, Takashi Kobayashi
    2007 Volume 76 Issue 2 Pages 279-287
    Published: 2007
    Released on J-STAGE: June 06, 2007
    JOURNAL FREE ACCESS
    To evaluate the incidence of cool summer damage as early as possible, we made a model to estimate the sterility percentage from the cool degree days in the consecutive developmental stages of young panicles. For estimation of the sterility percentage, we used nonparametric regression with, the limitation that the values of the adjoined partial regression coefficient β are not greatly different. The parameter for water temperature was decided from the relation between the water temperature and sterility percentage in the deep flooding experiments with cv. Akitakomachi. The contribution rate of the model using this parameter for estimation of sterile percentage was 77.2%. This parameter may be applied to other cultivars by assuming the difference of cool summer tolerance as the difference in the base temperatures of cool degree days. The base temperatures for cv. Sasanishiki, Akitakomachi and Hitomebore were 21.0°C, 20.5°C and 19.5°C, respectively. The parameter for air temperature was decided using several varieties with different cool summer tolerances the damage from cool summer in 2003 at Tohoku areas. The parameter of air temperature was useful for the evaluation of cool summer damage in the fields though the accuracy was lower than the parameter for water temperature. In conclusion, we can estimate the sterility percentage caused by cool summer in real time by running this model.
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  • Takashi Momii, Toshihiko Izawa
    2007 Volume 76 Issue 2 Pages 288-294
    Published: 2007
    Released on J-STAGE: June 06, 2007
    JOURNAL FREE ACCESS
    The effects of four fertilizer elements (nitrogen, phosphoric acid, potassium and lime) and compost on rice plant during the 77 years from 1926 were studied. Lack of adding nitrogen, phosphoric acid, potassium and lime significantly decreased the yield, conversely adding compost increased the yield. The ratio of the yield in the plot lacking nitrogen or phosphoric acid to that with four elements fertilized was considered to decrease gradually. On the contrary, the ratio of the yield in the plot with compost to that with four elements fertilized gradually increased. Therefore, it is considered that compost effect is increased gradually. However, it was uncertain why the ratio of the yield in the plot lacking potassium and lime to that with the four elements gradually increased. We found definite fertility of the soil without application of fertilizer and the effect of four elements on the yield.
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  • Kuniaki Fukui
    2007 Volume 76 Issue 2 Pages 295-300
    Published: 2007
    Released on J-STAGE: June 06, 2007
    JOURNAL FREE ACCESS
    A model for prediction of shoot elongation was applied to various regions in Japan, and its fitness was evaluated. In the model, the shoot elongation rate in one arbitrary day was decided by the average temperature and photoperiod on that day and shoot length by those on the previous day. Parameters of the model were determined for shoot elongation data of three cultivars ('Ichinose', 'Kairyou-nezumigaeshi' and 'Shin-ichinose') in four prefectures, Miyagi, Fukushima, Ibaraki and Kagoshima. When the maximal shoot elongation rate (PRmax) was determined independently for all prefectures, root mean square errors of the estimated shoot length were about 9 cm for all cultivars. The values fitted by the model represented actual annual fluctuation of shoot elongation well. Estimated values were also in good agreement with the measured data which were not used for determining parameters. Therefore, the model seemed to represent the response of mulberry vegetative growth to temperature and photoperiod.
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Research and Technical Note
  • Kazuhiko Ishizaki, Satoshi Kaneda, Takaaki Matsui
    2007 Volume 76 Issue 2 Pages 301-305
    Published: 2007
    Released on J-STAGE: June 06, 2007
    JOURNAL FREE ACCESS
    Glutinous rice is often processed to rice-cake (Mochi) and rice-crackers (Arare). Hot Mochi dough is difficult to cut and pack, and thus hardness of Mochi after cooling is an important processing property to shorten the manufacturing time. We evaluated the effect of cultivation method, including the amount of nitrogen fertilizer for ear manuring, date of planting and the kind of cultivar on hardness. The amount of nitrogen fertilizer was found to have a small effect on the hardness, but the interaction between the nitrogen fertilizer and cultivars was significant. There was a varietal difference in the response to the nitrogen fertilizer. The hardness of Wataboushi decreased but that of Koganemochi increased with increasing nitrogen fertilizer application. The date of planting and the kind of cultivar also significantly influenced the hardness, and their contribution rates were 6.4 % and 81.0 %, respectively. Decrease in temperature due to the 15-day delay of planting caused a 0.90 kg cm-2 decrease in hardness, and the hardness of Wataboushi was 3.10 kg cm-2 lower than that of Koganemochi. From these results, we conclude that selection of cultivar is of primary importance, and early planting is necessary to produce superior glutinous rice for processing. Thus, we recommend high-yield cultivation without palatability because the nitrogen fertilizer has only a small effect on the hardness.
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  • Akiko Shigemune, Hideki Sasahara, Akitoshi Goto, Kiyoyuki Miura, Tomoh ...
    2007 Volume 76 Issue 2 Pages 306-310
    Published: 2007
    Released on J-STAGE: June 06, 2007
    JOURNAL FREE ACCESS
    The precision of the eating quality test was analyzed for breeding the highly palatable rice variety. Varietal differences in overall eating quality, appearance, taste, stickiness and hardness were significant, but the varietal difference in flavor was not stable. There were significant positive correlation coefficients between the overall eating quality and the appearance, flavor, taste and stickiness. The correlation coefficient between overall eating quality and hardness was negative and not significant. The overall eating quality was largely explained by taste from the multiple regression analysis. Five out of 15 panel members could detect the difference among Koshihikari, Akitakomachi and Kochihibiki in overall eating quality at the 5% level of significance. The taste preference of these panel members tended to coincide with the mean value of all panel members. Five panel members out of 10 panel members could detect the difference between Koshihikari and Akitakomachi in overall eating quality at the 5% level of significance. These results show that the accuracy of eating quality test conducted in Hokuriku Research Center is satisfactory.
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  • Isao Sakata, Tomohiko Yoshida
    2007 Volume 76 Issue 2 Pages 311-316
    Published: 2007
    Released on J-STAGE: June 06, 2007
    JOURNAL FREE ACCESS
    Yellow spotting between the veins of spinach leaves has hindered the cultivation of spinach in the Andosol in Takane-cho district in Takayama city. This symptom was frequently seen in this district, although the degree of spotting varied. We sampled and analyzed the leaves of the plants with yellow spots (yellow leaves) and the leaves of normal green plants (green leaves) as well as the soil in the same field. The component with the lowest content in the yellow leaves as compared with that in the green leaves was manganese, and this was also the case in the soil. When the spinach with yellow leaves were sprayed with 2g L-1 manganese sulfate solution, the yellow spot symptoms disappeared four days later. Moreover, the easy reductive manganese content of the soil in the field where yellow spots were observed was much lower than that of the soil in another district where soluble phosphatic manure was applied in large quantities, or where yellow spots had not been observed. On the other hand, spinach with yellow spots often appeared on the soil whose manganese content was about 60 mg kg-1 in this district. Therefore, it was considered that the cause of yellow spotting in spinach in Takane-cho, Takayama city was the lack of manganese in the soil. The reason why yellow spots often appear even in the spinach grown on the soil with 60 mg kg-1 easily reducted manganese may be the strong adsorption ability of the Andosol.
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