Papers - ISHIGAKI Genki
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Agronomic performance, biomass production, and nutrient value of three napier grass cultivars (Pennisetum purpureum) in highland area Reviewed International coauthorship
Sidik Prasojo Y., Pastawan V., Prasetyo B., Kamal M., Khoirul Anwar M., Prastyo R.A., Iqbal Faruqi M., Ishigaki G.
BIO Web of Conferences 155 2025.1
Language：English Publishing type：Research paper (scientific journal) Publisher：BIO Web of Conferences
The study aims to determine the agronomic performance, biomass production, and nutrient value of three Pennisetum purpureum cultivar (Biovitas, Pakchong, and Mott) in 1000 meters above sea level (asl) highland area of Petungkriyono, Pekalongan, Central Java, Indonesia. The grasses were planted using vegetative stems and maintained for four months, following completely randomized design (CRD) with four replications for each cultivar. Agronomic performance was assessed before harvested. Napier grass was harvested to investigate the biomass production and nutrient values, including organic matter, crude protein, crude protein yield, crude fibre, and crude fat. Pakchong had the highest biomass and crude fiber content. Biovitas exhibited the highest agronomic performance, with superior plant height, leaf length, leaf width, and stem diameter, as well as the highest nutrient values in term of organic metters. Mott showed the highest tiller number and crude protein content among the cultivars. The distinct strength of each cultivar indicates their potential suitability for various agricultural applications in highland regions.
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Effect of yellow light irradiation on the growth of Maize (<i>Zea mays</i> L.) Reviewed
Ishigaki Genki, Adachi Tetsuya
Japanese Journal of Grassland Science 70 ( 4 ) 180 - 184 2025.1
Authorship：Lead author, Corresponding author Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japanese Society of Grassland Science
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Ishigaki G., Niimi M., Shigedomi H., Sasaki Y., Idota S., Ishii Y.
Grassland Research 3 ( 4 ) 364 - 372 2024.12
Publishing type：Research paper (scientific journal) Publisher：Grassland Research
Background: Pearl millet is characterized by its high dry matter (DM) yields with a high moisture content, which makes it difficult to process as silage. Methods: Pearl millet was sown in mid-September for 3 years to examine its growth, DM yields in early December, and decrease in DM percentage after frost exposure. The crop was processed as round-bale silage to assess silage quality and preference by breeding beef cattle. Results: Plants reached a height of 160–200 cm, with heading tiller percentages of 50%–70% in early December. With frost exposure, DM percentage increased in leaves and panicles, followed by stems, reaching over 40%, 1 month after exposure. These increases were positively correlated with cumulative frost exposure. After frost exposure, in vitro DM digestibility and crude protein content declined while acid detergent fiber content increased. Repeated cafeteria feeding experiments showed a reduced preference for either pearl millet silage or Italian ryegrass hay. The silage showed moderate acidity at pH 4.73–5.40, with lactic acid at 0.58%–1.62% DM, acetic acid at 0.03%–0.10% DM, and negligible butyric acid, indicating a satisfactory quality. Conclusions: In Southern Kyushu, pearl millet sown in late summer can be processed into low-moisture round-bale silage in January, the year following sowing.
DOI： 10.1002/glr2.12096
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Niimi M., Kurata M., Ishigaki G., Ishii Y.
OnLine Journal of Biological Sciences 25 ( 1 ) 125 - 133 2024
Publishing type：Research paper (scientific journal) Publisher：OnLine Journal of Biological Sciences
Underutilization of bamboo contributes to the degradation of woody environments in southern Kyushu, Japan. A novel approach to using bamboo involves processing it to finely ground silage, although this product has shown inferior digestibility and palatability compared to traditional forage crops. This study evaluated the chemical composition, fermentation quality, and aerobic stability of silages produced from Italian ryegrass, maize, and Rhodes grass mixed with 10% (v/v) bamboo silage, ensiled for 30-40 days. One-day wilted first-cut Italian ryegrass and Rhodes grass and direct-cut maize were finely chopped, mixed with bamboo silage at a 9:1 volume ratio, and vacuum-sealed in polyethylene bags, with control silages produced without bamboo addition. Digestibility tended to decrease in bamboo-mixed maize and Rhodes grass silages. The addition of bamboo silage resulted in a significant decrease (p<0.05) in pH by 0.45 in Italian ryegrass, a trend toward lower pH in Rhodes grass, and a tendency for pH to increase in maize. Fermentation quality was improved by the addition of bamboo silage in Italian ryegrass and Rhodes grass, with significant increases (p<0.05) in contents of lactic acid by 2.91% Dry Matter (DM) and acetic acid by 1.03% DM, respectively, contrasting with a trend toward reduced lactic acid content in maize. Aerobic stability, measured as the time to reach a temperature increase of >2°C above ambient, was highest in Italian ryegrass silage with bamboo, which maintained stability for more than 6 days after air exposure, compared to significant temperature rises detected at 15 and 29 h in maize and Rhodes grass silages, respectively. Fermentation quality, including pH, lactic acid, and acetic acid contents, was maintained in Italian ryegrass silage mixed with bamboo for a week after air exposure, while rapid deterioration was observed in maize and Italian ryegrass silages with and without bamboo silage addition. It is concluded that wilted Italian ryegrass mixed with 10% bamboo silage may enhance the handling efficiency of silage after opening silos in early June for the site in southern Kyushu, Japan.
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Tiller Number and Flowering Ability on BC1F1 Progeny of Interspecific Hybridization in Ruzigrass (Urochloa ruziziensis) Reviewed International coauthorship
Sidik Prasojo Y., Nitthaisong P., Muguerza M., Kamphayae S., Umami N., Ishigaki G.
BIO Web of Conferences 80 2023.12
Authorship：Last author Language：English Publishing type：Research paper (scientific journal) Publisher：BIO Web of Conferences
The objective of this study focusing on production BC1F1 progeny of interspecific hybridization in ruzigrass (Urochloa ruziziensis) were to evaluate potential of pentaploid BC1F1 hybrid for seed propagation by associating with their tiller number, flowering, and shattering ability. In addition, we evaluate the function of various nitrogen dose on vegetative stages. Eight different genotypes were examined: B. ruziziensis 'Kennedy', B. decumbens 'Basilisk', pentaploid BC1F1 line derived from B. ruziziensis and Mulato (RM), pentaploid BC1F1 line derived from diploid B. ruziziensis and tetraploid B. ruziziensis (RR), and pentaploid BC1F1 lines derived from B. ruziziensis and B. decumbens (RD 1-4). The experimental plants treated with three level of nitrogen fertilizer (0, 4, and 8 kg/10a). Compared with parental line, RM line had high tiller number along with increasing level of nitrogen. For the flowering and shattering ability, the first lines to flowered and shattered was the pentaploid BC1F1 (RD 1-4), RR, and B. decumbens. Pentaploid BC1F1 lines derived from B. ruziziensis and B. decumbens (RD 1-4) had potential for seed propagation by associating with their flowering and shattering ability, while pentaploid BC1F1 line derived from B. ruziziensis and Mulato (RM) had the potential biomass production and yield ability by associating with its tiller number production.
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The effects of the different sowing methods and planting density on the yield components of soybean (Glycine max) under intercropping condition with rhodes grass (Chloris gayana Kunth.) Reviewed International coauthorship
Prasojo Y.S., Niimi M., Hashiguchi M., Muguerza M., Ishigaki G.
Australian Journal of Crop Science 17 ( 10 ) 770 - 775 2023.10
Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：Australian Journal of Crop Science
In Japan, grass-legume intercropping systems are being developed to increase quality and yield of grain and forage. Hence, this study evaluated the effects of sowing methods and planting density on yield traits of forage soybean under intercropping condition with rhodes grass. The field experiment was laid on in a completely randomized block design with four treatments and four replications. Rhodes grass seeds were sown at 2.8 kg/10a in a field containing mono- and intercropping-plots. For soybeans, two levels of sowing densities (about 15 or 30 seeds/m2: named “L” and “H”) and two sowing methods (row or spray: named “R” and “S”) were applied for a total of four different intercropping combinations. Rhodes grass DMY obtained the highest in low level of sowing density with rowing methods (LR) (338 kg/10a) while soybean DMY obtained the highest in high level of sowing density with rowing methods (HR) (251 kg/10a) and in high level of sowing density with spray methods (HS) (177 kg/10a). Intercropping at low density increased CP (12%) and CPY (40.4 kg DM/10a) in Rhodes grass, and CP (18.9%) in soybeans, whereas high sowing density increased soybean CPY in HR (41.5 kg DM/10a) and contributed to higher soybean CPY in DM percentage at 66% (HS) and 56% (HR). Overall, high density sowing increased the 1st total DMY while row sowing increased the 1st total CPY in both crops at the first cutting, while monocropping increased Rhodes grass yield and plant length at the second-cutting. Also, sowing soybean by a broadcast spreader could obtain sufficient crude protein yield as a forage soybean in southern Kyushu, Japan. Further studies are needed for soybean overseeding method and use of early-maturity soybean lines.
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Crude Protein Content Estimation of Rhodes Grass Using Vegetation Indices Calculated by the Spectral Reflectance Reviewed
Arai Masakazu, Nakamura Keishiro, Ishigaki Genki
Japanese Journal of Grassland Science 69 ( 1 ) 23 - 26 2023.4
Authorship：Last author Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japanese Society of Grassland Science
DOI： 10.14941/grass.69.23
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Honda N., Ishigaki G.
Australian Journal of Crop Science 17 ( 2 ) 240 - 243 2023.2
Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：Australian Journal of Crop Science
This study aimed to clarify the effect of water priming on the seed moisture and the rooting rate of soybean *Glycine max (L.) Merr.+ ‘Fukuyutaka’ for developing a cultivation method, where soybean seeds can directly be sown on the meadow or grassland for livestock production. The weight of each soybean seed was measured before and after they were subjected to: no treatment (control), and, two kinds of priming treatments, soaking (2 and 4 h), and moisture absorption (3, 12, and 24 h). The weight of seeds was additionally measured after keeping them at a specified temperature (28–30°C) and humidity (58–60%) for 4 h, 1, 2, and 3 days. The moisture content of soybean seeds was calculated based on their weights pre and post-treatment. The rooting rate of the seeds was investigated after each priming (control, soaking, and moisture absorption), 48 h of standing and irrigation treatment. The seed moisture content of soybean seeds increased immediately after priming (soaking or moisture absorption treatment), however, after standing, the moisture content in both treatments deceased to the same level as that of control. The rooting rate in both priming pre-treatments was similar to or lower than that in control, indicating that neither soaking nor moisture absorption of soybean seeds had a keeping moisture content of seeds for long time which promoting effect on rooting of soybean under dry condition on meadow or grassland.
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Tissue Culture and Somatic Embryogenesis in Warm-Season Grasses—Current Status and Its Applications: A Review Reviewed International coauthorship
Muguerza M.B., Gondo T., Ishigaki G., Shimamoto Y., Umami N., Nitthaisong P., Rahman M.M., Akashi R.
Plants 11 ( 9 ) 2022.5
Language：English Publishing type：Research paper (scientific journal) Publisher：Plants
Warm-season grasses are C4 plants and have a high capacity for biomass productivity. These grasses are utilized in many agricultural production systems with their greatest value as feeds for livestock, bioethanol, and turf. However, many important warm-season perennial grasses mul-tiply either by vegetative propagation or form their seeds by an asexual mode of reproduction called apomixis. Therefore, the improvement of these grasses by conventional breeding is difficult and is dependent on the availability of natural genetic variation and its manipulation through breeding and selection. Recent studies have indicated that plant tissue culture system through somatic em-bryogenesis complements and could further develop conventional breeding programs by micro-propagation, somaclonal variation, somatic hybridization, genetic transformation, and genome ed-iting. This review summarizes the tissue culture and somatic embryogenesis in warm-season grasses and focus on current status and above applications including the author’s progress.
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Investigation on Spraying Percentage of Droplets at Leaves and Ears using Several Pesticide Spraying Methods in Several Growth Stages of Maize (<i>Zea mays</i> L.) Reviewed
Ishigaki Genki, Idota Sachiko, Ishii Yasuyuki
Japanese Journal of Grassland Science 67 ( 4 ) 183 - 188 2022.4
Authorship：Lead author Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japanese Society of Grassland Science
To clarify a basic knowledge on pesticide application methods against fall armyworm (<i>Spodoptera frugiperda</i>), we investigated the spraying percentage of droplets on leaves and ears covered by water-sensitive paper using several pesticide-spraying methods, including tractor-mounted boom sprayers, handheld electrostatic sprayer, and drone-spraying at various growth stages of maize (<i>Zea mays</i>). In boom spraying methods, the spraying percentages of droplets under the sprayed rate of 200 L per 10 a at the 1st-2nd leaf stage was over than 98％. In the case of 100 L per 10 a at the 5-6th leaf stage, they were less than 50％. For the tractor-mounted boom sprayer, spraying percentages of droplets at the top- and middle-leaves in the 9-10th leaves stage were lower than those at the lower-leaves. On the other hand, the electrostatic sprayer exhibited the opposite results. In drone-spraying at the dough-ripe maize, they were obtained more than 60％ in base and middle part of upper- and middle-leaves under the amount of 100 L per 10 a. These results elucidate important information that contributes to our basic knowledge on the selection of pesticide application methods against fall armyworm. It will be necessary to clarify the relationship between the spraying percentage of droplets and the control/exterminating effect.
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EFFECT OF SOYBEAN (GLYCINE MAX L. MERR) INTERCROPPING INTO RHODESGRASS (CHLORIS GAYANA KUNTH.) ON DRY MATTER YIELD, CRUDE PROTEIN, AND SILAGE CHARACTERISTICS GROWN IN SOUTHWEST JAPAN Reviewed International coauthorship
Prasojo Y.S., Niimi M., Rahman M.M., Ishigaki G., Akashi R.
Journal of Animal and Plant Sciences 32 ( 2 ) 460 - 465 2022.4
Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Animal and Plant Sciences
This study aimed to investigate the quantify yield and silage quality response of forage soybean ( Glycine max L. Merr) intercropping into rhodesgrass ( Chloris gayana Kunth.) cultivation compare to monoculture rhodesgrass in warm temperate zone. Rhodesgrass and soybean were intercropped in 2017 and 2018 at Sumiyoshi Livestock Science Station, University of Miyazaki in southwest Japan. As the results, there were no differences between the height of monocultured rhodesgrass (MC) and intercropped rhodesgrass (IC). Height of soybean was less than rhodesgrass. Dry matter yield (DMY) was not significantly different between MC and IC in both years. For soybean ratio of intercropped total yield, the two-years-average was 18.3%. The lower soybean ratio of intercropped total yield in 2018 (13.3%) than those in 2017 (30.8%) seems to be caused by the larger rhodesgrass DMY. Crude protein (CP) content of IC (11.0%) was not significantly higher than that of MC (10.6%). There was no significant difference of CP yield between MC (28.3 kg/10 a) and IC (22.3 kg/10 a). All silages produced in this two-year experiment had only trace amounts of organic acids and volatile basic nitrogen regardless of the presence of soybean. In conclusion, the existence of soybean did not affect the silage quality. Early growth type soybean cultivar, appreciate harvesting time and fertilizer improvement might be increase DMY and CP with soybean intercropping.
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A review of okara (soybean curd residue) utilization as animal feed: Nutritive value and animal performance aspects Reviewed International coauthorship
Rahman M.M., Mat K., Ishigaki G., Akashi R.
Animal science journal = Nihon chikusan Gakkaiho 92 ( 1 ) 2021.12
Language：English Publishing type：Research paper (scientific journal) Publisher：Animal science journal = Nihon chikusan Gakkaiho
Year by year, huge quantities of by-products are generated during the manufacturing process of soybean-based products. Okara is one of the by-products, and it is an insoluble portion of the soybean. It consists of high moisture (8.4-22.9%); on dry matter basis, it contains high metabolizable energy (9.0-14.2 MJ/kg) and other components that include crude protein (20.9-39.1%), crude fiber (12.2-61.3%), crude fat (4.9-21.5%), and ash (3.4-5.3%). Fermentation of okara improves its nutritional quality and reduces its anti-nutrient contents. Due to animals' palatability, okara can be used to replace the soybean meal/concentrate feed partially or completely in ruminant's diet and partially in nonruminant's diet. Okara feeding does not depress the intake, digestibility, growth, milk production, blood metabolic profiles, and meat quality of animals. However, this by-product decays quickly due to its high moisture content, and its heavy weight and sticky nature make it difficult to process and expensive to dry using conventional methods. This paper thoroughly summarizes the utilization of okara as animal feed in the cause of developing a general guideline with favorable levels of inclusion in the diets of animals for its exploitation and valorization. This review will encourage further research to develop eco-friendly and value added feed for animals.
DOI： 10.1111/asj.13594
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Forage-Yield Estimation Using LiDAR and a Drone Reviewed
49 ( 10 ) 580 - 584 2021.10
Language：Japanese Publishing type：Research paper (scientific journal)
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Evaluation of corn-soybean inter-cropping systems in southwestern Japan Reviewed International coauthorship
AHMAD SEYAR AZIZI, IKUO KOBAYASHI, JONATHAN CHUUKA, GENKI ISHIGAKI
Tropical Grasslands-Forrajes Tropicales 9 ( 3 ) 307 - 314 2021.9
Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal)
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Effect of different growth stages on biomass weight and forage quality of different growth type soybean (Glycine max) Reviewed International coauthorship
Prasojo Y.S., Ishigaki G., Hashiguchi M., Akashi R.
Asian Journal of Plant Sciences 20 ( 2 ) 256 - 262 2021
Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：Asian Journal of Plant Sciences
Background and Objective: The dry matter yield, fiber content, crude protein content and crude protein yield should depend on the cutting stage of each different soybean cultivars. This study aimed to clarify the effect of different growth stages on biomass weight and forage quality of different growth type soybean (Glycine max) in temperate low warm region, Japan. Materials and Methods: Determinate growth (DET) soybeans (Fukuyutaka, Norin 2), Indeterminate growth (IND) soybeans (Moshidou Gong 503, Williams 82) and an unknown growing type soybean (Kohamadaizu) were sowed in the beginning of June 2019 and harvested at three stages (R1, beginning of flowering stage, R2, full flowering stage, R5, beginning of seed development). The study was conducted as a randomized complete block design with three replications. Results: Fukuyutaka, Kohamadaizu and Norin 2 were reached flowering stage later than Moshidou Gong 503 and Williams 82. Longer time for growth stages of Fukuyutaka, Kohamadaizu and Norin 2 was resulting in high plant height, stem diameter, number of branches, number of leaves and dry matter weight. The amount of fiber content (ADF and NDF) was decreasing as stages developed for Fukuyutaka, Kohamadaizu and Norin 2. In another hand, fiber content of Moshidou Gong 503 and Williams 82 was increased as stages increasing. The CP weight was increased as advancing growth stages for all cultivars. Conclusion: Fukuyutaka and Kohamadaizu could be suitable in the utilization of soybean forage for feed livestock in the temperate low warm region in Japan.
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Evaluation of regrowth ability of soybeans for forage utilization under two-cutting systems Reviewed
Prasojo Y.S., Ishigaki G., Hashiguchi M., Muguerza M., Akashi R.
Australian Journal of Crop Science 15 ( 12 ) 1452 - 1458 2021
Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：Australian Journal of Crop Science
Soybean (Glycine max) has the potential as forage feed because of its high protein content and low fiber. Intercropping soybean with tropical forage grasses can improve forage quality and increase yield. However, their optimum cutting interval under mixed cropping system is still unknown. This study aimed to investigate regrowth ability and performance of soybean plant under two different cutting heights in Miyazaki, Southwestern of Japan, which has a humid subtropical climate with relatively high temperature and evenly distributed precipitation throughout the year. The experimental design was randomized block design arrange in 3 × 2 factorial scheme (soybean cultivars × cutting treatments). Three soybean accessions (Glycine max ‘Fukuyutaka’, G. max ‘Kohamdaizu’ and G. gracilis ‘Moshidou Gong 503’) with 5 replications were cultivated under single seeding condition. Soybeans were defoliated after 50 d of cultivation under low level cutting height (LC, 7.5 cm) and high level cutting height (HC, 12 cm). ‘Fukuyutaka’ achieved 100% regrowth rate in both LC and HC. Although the regrowth rate for ‘Kohamadaizu’ was 100% in the HC, it was only 20% in LC. ‘Fukuyutaka’ was more robust and high tolerant for defoliation stress than that of ‘Kohamadaizu. In other hand, no plants exhibited regrowth in both cutting heights for ‘Moshidou Gong 503’. For ‘Fukuyutaka’ and ‘Kohamadaizu’, the number of branching nodes with re-emergent leaves was significantly higher in the HC. In both cutting height of ‘Fukuyutaka’, plant continued elongating and exhibited vigorous growth until 2nd cutting. The cutting height levels, height of cotyledonary node and growth stage of soybean plant when harvested at the 1stcutting significantly affected the regrowth ability of soybeans. In conclusion, ‘Fukuyutaka’ showed the ability for regrowth under LC and HC. HC provided significantly higher fresh matter and dry matter weight than that LC. Further study is needed to evaluate the performance of ‘Fukuyutaka’ under intercropping cultivation with tropical forage grasses. This is the first report to establish an approach for two-cutting soybean as forage
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Sakakura M., Kita N., Ishigaki G., Arai M.
26th Microoptics Conference, MOC 2021 2021
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：26th Microoptics Conference, MOC 2021
We investigated the correlation among the crude protein content of grass, the vegetation index and fluorescence intensity for non-destructive nutrient estimation in farm land. Vegetation index image was measured through optical band pass filter under sunlight. Fluorescence was measured under blue LED irradiation. We confirmed high correlation to crude protein content.
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Replacement of soybean meal with levels of inclusion of soya waste in the diet of growing goats Reviewed
Rahman M.M., Abdullah R.B., Mat K.B., Ishigaki G., Nor M.M., Akashi R.
Tropical Animal Health and Production 52 ( 6 ) 3085 - 3090 2020.11
Language：English Publishing type：Research paper (scientific journal) Publisher：Tropical Animal Health and Production
© 2020, Springer Nature B.V. An experiment was conducted to investigate the effect of replacing soybean meal with soya waste at different levels on intake, digestibility and growth in goats. Eighteen male goat kids with initial body weight (BW) of 13.0 kg were distributed equally to three dietary groups. They were fed Napier grass (Pennisetum purpureum) and concentrate mixture, and each goat was assigned to an individual pen. Soybean meal in the concentrate mixture was replaced with soya waste at 0% (T1), 50% (T2) and 100% (T3) levels in respective dietary groups. These diets were isocaloric and isonitrogenous. Results showed that animals fed T3 diet exhibited higher Napier grass intake than those fed T1 or T2 diet. There was no influence on total intakes of dry matter (DM), organic matter (OM), crude protein (CP), metabolic BW, per cent BW and metabolisable energy by the dietary groups. However, there was an increasing trend on intake and digestibility of neutral detergent fibre (NDF) with increasing levels of soya waste in the diets. Animals fed T3 diet showed higher intake and digestibility of NDF than those fed T1 diet. There was no influence of the dietary groups on digestibilities of DM, OM and CP. Similarly, there was no effect of them on the final BW, total BW gain, daily BW gain, feed conversion ratio and feed cost. Soya waste can replace 100% soybean meal in diets for growing goats, because no change was observed in nutrient intake, digestibility and growth performance; inclusion of soya waste enhanced the intake and digestibility of NDF.
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Puspasari R., Hashiguchi M., Ushio R., Ishigaki G., Tanaka H., Akashi R.
Plant and Soil 2020.1
Language：English Publishing type：Research paper (scientific journal) Publisher：Plant and Soil
© 2019, Springer Nature Switzerland AG. Aim: “Super-Root” (SR) is a fast-growing root culture established in the legume forage species Lotus corniculatus that displays vigorous growth and high embryogenic capacity, uniquely allowing for continuous root cloning, direct somatic embryogenesis, and mass regeneration of plants under hormone-free culture conditions. This study’s primary aim was to verify the possibility of introducing the SR trait to another legume species as a means of enhancing root traits. Our previous research produced a F1-generation hybrid between the colchicine-doubled form of the diploid Lotus japonicus ‘Miyakojima’ MG-20 and SR-derived Lotus corniculatus. The current study’s focus was to evaluate the root phenotype of the F2-generation to confirm the introduction of SR characteristics to Lotus japonicus. Methods: We assessed 242 rooted F2-hybrid progeny using cluster analysis, concentrating on four morphological root traits: root fresh weight, total root length, maximum root length, and root diameter. Principal Component Analysis (PCA) was used to determine the correlations among eight traits of the F2-progeny of the WinRhizo root morphological measurement data and to identify what traits contributed most to their root variation. Results: The 242-hybrid progeny and both parents were grouped into eight different clusters using a similarity phenogram. One cluster consisted of lines 36, 82, 86 and 184 that considerably exceeded the RFW, TRL, and MRL values of the L. japonicus and SR parents. Conclusion: The results confirmed the introduction of SR traits to the F2-hybrid progeny and identified potential candidates for breeding and gene isolation that will be conducted to expand the scope of this research.
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モンモリロナイトの表面散布による牛および豚排せつ物由来の数種臭気原因物質の低減効果 Reviewed
石垣 元気, 小林 郁雄
日本暖地畜産学会報 63 ( 1 ) 13 - 16 2020
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：日本暖地畜産学会
本研究では，飼養管理の異なる4種類の家畜（繁殖牛，乳牛，肥育牛および繁殖豚）の排せつ物にモンモリロナイトを表面散布することにより，家畜排せつ物由来の臭気の原因となる物質濃度を調査し，家畜排せつ物の臭気原因物質の低減効果について評価した．原因物質のうち，アンモニア（NH<sub>3</sub>）および酢酸濃度（CH<sub>3</sub>COOH）の増加が乳牛糞および豚糞において顕著であった．特に，豚糞におけるアンモニア濃度は，処理後7日目において最も高くなった．しかしながら，その値はモンモリロナイト散布の有無によって異なっており，モンモリロナイト0 kg/m<sup>2 </sup>散布区では80.0 ppm であったのに対し，モンモリロナイト1.5 kg/m<sup>2 </sup>散布区では41.3 ppm まで減少した（<i>P</i> < 0.05）．乳牛糞のNH<sub>3 </sub>濃度もモンモリロナイト1.5 kg/m<sup>2 </sup>散布区（25.3 ppm）がモンモリロナイト0 kg/m<sup>2 </sup>散布区（42.7 ppm）と比べて有意に減少した（<i>P</i> < 0.05）．また，豚糞のモンモリロナイト1.5 kg/m<sup>2 </sup>散布区のCH<sub>3</sub>COOH 濃度の減少も同様に認められた．以上の結果から，モンモリロナイトの家畜糞への表面散布は，いくつかの臭気原因物質において減臭効果があることが示唆された．
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Prasojo Y., Ishigaki G., Fukuyama K., Akashi R.
IOP Conference Series: Earth and Environmental Science 387 ( 1 ) 2019.12
Language：English Publishing type：Research paper (scientific journal) Publisher：IOP Conference Series: Earth and Environmental Science
© Published under licence by IOP Publishing Ltd. Tropical grasses mainly utilized in southwestern Japan exhibited that the dry matter yield is increased as the growth stage. However, the nutritive value, such as crude protein (CP) and non-fibrous carbohydrate (NFC) decreased strikingly. Therefore, breeding for the new grass or crops with high potential as protein source is an urgent problem. The aim of the study were to investigate the dry matter yield of two soybean cultivars ('Miyakonojo' and 'Williams82') with Rhodes grass as living mulch plant after 1st cutting and to investigate the nutritive value of the silage. The growth of the Rhodes grass hampered the growth of soybean at the initial and the subsequent growth stages. Hence, the dry matter yield of soybean ranged from 9.8 kg/10a to 26.6 kg/10a, correspond to about 3 to 10% of total dry matter yield. The nutritive value of EE, CA and CP in Rhodes grass with soybean silage higher than those of Rhodes grass silage. These results suggest that the addition of soybean biomass could be useful for increasing the nutrition value of silage. Moreover, it is necessary to choose an appropriate sowing date to increase dry matter yield of soybean biomass in southwestern of Japan.
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Nitthaisong P., Ishigaki G., Suenaga K., Muguerza M., Tanaka H., Akashi R.
Crop Science 59 ( 4 ) 1648 - 1656 2019.7
Language：English Publishing type：Research paper (scientific journal) Publisher：Crop Science
© 2019 The Author(s). Urochloa species are a rich source of quality forage in the tropical and subtropical areas, and cultivated species are predominantly facultative apomictic. They are well adapted to poor soil conditions, resistant to heavy grazing, and drought tolerant, but some Urochloa species produce poor pasture and seed yield. Therefore, it is important to complement and to combine characteristics of different species in breeding programs. We have conducted interspecific crosses between diploid U. ruziziensis (R. Germ. & C. M. Evrard) Crins ‘Kennedy’ (2n = 2x = 18) with apomictic tetraploids U. decumbens (Stapf) R. D. Webster ‘Basilisk’ (2n = 4x = 36) and U. brizantha (Hochst. ex A. Rich.) R. D. Webster ‘Marandu’ (2n = 4x = 36). Diploid, triploid, and tetraploid plants were obtained from these crosses. The triploid plants were further crossed with ‘Basilisk’ to produce a BC1F1 generation. Although no seeds were produced by self-pollination of the F1 triploid hybrids, backcrossing eventually produced triploid, tetraploid, and pentaploid plants (BC1F1). Only the pentaploid plants produced seeds by self-pollination. This is the first report of the production of apomictic pentaploid progenies from interspecific crosses in Urochloa.
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Evaluation of Drying Characteristics of Rhodesgrass (Chloris gayana) and New Tetraploid Ruzigrass (Urochloa ruziziensis) Reviewed
Genki Ishigaki, Yogi Sidik Prasojo, Pattama Nitthaisong, Kiichi Fukuyama, Ryo Akashi
日本暖地畜産学会報 62 ( 1 ) 25 - 30 2019.3
Language：Japanese Publishing type：Research paper (scientific journal)
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Ishigaki G., Nitthaisong P., Prasojo Y., Kobayashi I., Fukuyama K., Rahman M., Akashi R.
Asian-Australasian Journal of Animal Sciences 31 ( 5 ) 748 - 754 2018.5
Language：English Publishing type：Research paper (scientific journal) Publisher：Asian-Australasian Journal of Animal Sciences
Copyright © 2018 by Asian-Australasian Journal of Animal Sciences. Objective: The preference evaluation of cattle is an important factor for estimation and improvement of the grazing amounts of newly introduced or bred grasses or cultivars in barn. This study was performed to assess the grazing behavior (the amount of grazing and/or the grazing speed) of cattle as indirect method using newly bred Brachiaria ruziziensis tetraploid strain ‘OKI1’(BR) hay as treatment group and Cloris gayana ‘Callide’ (CG) hay as control group. It also compared the feasibility of using behavioral differences between two groups as one criteria for evaluating preference by Japanese black cattle in barn. Methods: Three experiments were carried out using 12 growing Japanese Black cattle including 6 males and 6 females. In each experiment, the four Japanese Black cattle (2 males and 2 females) were placed in separated stall and allowed to graze BR and CG in manger that was separated into two portions for about 30 min. The position and behavior of the cattle were recorded, and weighed the residual of each gay at 15 and 30 minutes after experiment start. Results: The BR was superior to CG in chemical composition such as protein, fibers and nonfibrous carbohydrate. The cattle, over all, tended to prefer BR over CG in the first half 15 minutes in terms of the time spent and amount of grazing. Additionally, growing cattle exhibited neophilia for BR bred newly. Conclusion: These findings indicated the current approach could be applied for one of criteria to evaluate the preference of hay by Japanese black cattle under indoor housing environment.
DOI： 10.5713/ajas.17.0543
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Wee C., Hashiguchi M., Ishigaki G., Muguerza M., Oba C., Abe J., Harada K., Akashi R.
Plant Genetic Resources: Characterisation and Utilisation 16 ( 2 ) 94 - 102 2018.4
Language：English Publishing type：Research paper (scientific journal) Publisher：Plant Genetic Resources: Characterisation and Utilisation
© NIAB 2017. Seed composition, including the protein, lipid and sucrose contents of 334 accessions of wild soybean(Glycine soja) collected in Japan, was evaluated using near-infrared reflectance spectroscopy(NIRS) technology. The distribution of protein, lipid and sucrose contents and correlations amongthese three classes of seed components were determined. Protein, lipid and sucrose levels ranged inaccessions from 48.6 to 57.0, 9.0 to 14.3 and 1.24 to 3.53%, respectively. Average levels of protein,lipid and sucrose in the accessions were 54, 11 and 2.5%, respectively. High negative correlationswere observed between the protein and lipid contents, and the protein and sucrose contents. Meanlevels of the three constituents were compared among collection sites classified by climatic conditions.The total protein content of accessions from regions with a high annual mean temperature washigh. The protein content of accessions from the II-1 region was higher than those from the III-3region, and the sucrose content from the II-1 region was lower than those from regions III-2 andIV-3. The lipid content of plants from the II-1 region was lower than those from other regions,and the accessions in region II had a higher protein content and lower sucrose and lipid contentsthan the other regions. These results provide diverse and wide-ranged protein, lipid and sucrosecontents information of Japanese wild soybean resources according to climatic region; thus, providinga foundation for the future development and selection of new soybean varieties with desiredtraits in global environmental changes.
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Grazing potential of foggage and fresh dwarf Napiergrass pasture by breeding beef cows in southern Kyushu, Japan.
Kadwal MH, Ishii Y, Goto A, Li BK, Idota S, Niimi M, Ishigaki G, Fukuyama K
Wulfenia Journal 24 140 - 157 2018.1
Language：Japanese Publishing type：Research paper (scientific journal)
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Compaction Resistance of some species in Tropical grasses Reviewed
ISHIGAKI Genki, NITTHAISONG Pattama, AKASHI Ryo, FUKUYAMA Kiichi
Nihon Danchi Chikusan Gakkaihou 61 ( 1 ) 27 - 32 2018
Authorship：Lead author Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Warm Regional Society of Animal Science, Japan
Heavy field equipment contributes to plant compaction and soil compaction. These phenomena impede many physiological deteriorations in tiller generation, leaf elongation and root activities and cause stunting and yield loss in grasses. We conducted a comparative study between two <i>Brachiaria</i> grasses (<i>B. ruziziensis</i> and <i>B. brizantha</i>) and rhodes grass (<i>Chloris gayana</i>). Compact pressure was conducted by one side wheel of agricultural machinery (gross weight: 2.7 t) for three times. The tolerance capacity of the three tropical grasses was investigated in terms of plant length, stem diameter, leaf emergence speed, the transition of the number of tillers and dry matter yield. For plant length and stem diameter, a significant difference (<i>P</i> < 0.05) was recognized between compaction treatment and non-compaction treatment in rhodes grass. The leaf emergence speed was decreased under compaction treatment in palisade grass significantly (<i>P</i> < 0.05). For the number of tiller regenerated, rhodes grass showed the highest value among grasses. On the other hand, ruzi grass and palisade grass exhibited the vigorous generation of new tillers after first cutting regardless of compaction treatment. The amount of second dry matter yield of three grasses were ordered as follows: palisade grass > ruzi grass > rhodes grass although the differences were not significant. In conclusion, these tropical grasses varied the responses against the compact pressure because of the differences of plant part influenced and the degree, and the different approach for the maintenance the number of tillers. Additionally, ruzi grass and palisade grass were more superior than rhodes grass, indicating that these new introduced forage grasses can be useful as an annual forage production under agricultural machinery system.
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Asanuma Y, Gondo T, Ishigaki G, Inoue K, Zaita N, Muguerza M, Akashi R
GM Crops and Food 8 ( 2 ) 106 - 116 2017.4
Language：English Publishing type：Research paper (scientific journal) Publisher：GM Crops and Food
© 2017 Taylor & Francis. Japan imports cottonseed mainly from Australia and the USA where more than 96% of all cotton varieties grown are genetically modified (GM). GM crops undergo an environmental risk assessment (ERA) under the Law Concerning the Conservation and Sustainable Use of Biological Diversity before import into Japan. Potential adverse effects on biodiversity are comprehensively assessed based on competitiveness, production of harmful substances and outcrossing ability. Even though imported cottonseed is intended for food and feed uses and not for cultivation, the potential risks from seed spillage during transport must be evaluated. In most cases, the ERA requires data collected from in-country field trials to demonstrate how the GM crop behaves in Japan's environment. Confined field trials in Japan were conducted for the ERA of Lepidoptera-resistant and glufosinate-tolerant GM cotton (Gossypium hirsutum L.) lines GHB119 and T304-40. These lines were compared with conventional varieties for growth habit, morphological characteristics, seed dormancy, and allelopathic activity associated with competitiveness and production of harmful substances. Outcrossing ability was not a concern due to the absence of sexually compatible wild relatives in Japan. Although slight statistical differences were observed between the GM line and its conventional comparator for some morphological characteristics, transgenes or transformation were not considered to be responsible for these differences. The trial demonstrated that competitiveness and production of harmful substances by these GM cotton lines were equivalent to conventional cotton varieties that have a long history of safe use, and no potential adverse effects to biosafety in Japan were observed.
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Nitthaisong P., Ishigaki G., Fukuyama K., Akashi R.
Grassland Science 63 ( 2 ) 79 - 84 2017.4
Language：English Publishing type：Research paper (scientific journal) Publisher：Grassland Science
© 2017 Japanese Society of Grassland Science Tropical grasses with high forage quality and biomass could be grown as annuals in warm subtropical regions as an additional source of feedstock. For sustainable forage production, it is also vital to know the interactions between plant and weed for the selection of promising alternating forage grass. Brachiaria grass has been used as source of high quality forage in the tropics, and this could be developed as a promising forage grass species in this region. Therefore, this study compared the agronomic traits, productivity, and dominance to weeds in six Brachiaria cultivars with two rhodesgrass cultivars in southwestern Kyushu, Japan. This study was evaluated twice from spring to autumn in 2012. Most Brachiaria cultivars grew more vigorously than the two rhodesgrass cultivars during early seedling development in 2012. Except for ‘Llanero’, all Brachiaria cultivars had a higher dry matter yield than the two rhodesgrass cultivars. Notably, ‘Kennedy’ had the highest dry matter yield of 9.5 t ha−1 at the second cutting, resulting from substantial regrowth after the first cutting. However, two Brachiaria cultivars and one rhodesgrass cultivar evaluated in 2014 were not significantly different. Except ‘Llanero’, biomass percentage in all Brachiaria cultivars ranged from 57 to 81% at the first cutting. Subsequently, the value for the second cutting increased more than 90%. There was a significant positive correlation (P < 0.01) between dominance to weeds and growth in the early stage, indicating that the vigorous growth of Brachiaria grasses, during the early stage was superior to that of weeds in their competition. In addition, Brachiaria ruziziensis and Brachiaria decumbens could be introduced as new variety in temperate low warm region, Japan.
DOI： 10.1111/grs.12151
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Sequencing and comparative analyses of the genomes of zoysiagrasses Reviewed
Tanaka H., Hirakawa H., Kosugi S., Nakayama S., Ono A., Watanabe A., Hashiguchi M., Gondo T., Ishigaki G., Muguerza M., Shimizu K., Sawamura N., Inoue T., Shigeki Y., Ohno N., Tabata S., Akashi R., Sato S.
DNA Research 23 ( 2 ) 171 - 180 2016.4
Language：English Publishing type：Research paper (scientific journal) Publisher：DNA Research
© The Author 2016. Published by Oxford University Press on behalf of Kazusa DNA Research Institute. Zoysia is a warm-season turfgrass, which comprises 11 allotetraploid species (2n = 4x = 40), each possessing different morphological and physiological traits. To characterize the genetic systems of Zoysia plants and to analyse their structural and functional differences in individual species and accessions, we sequenced the genomes of Zoysia species using HiSeq and MiSeq platforms. As a reference sequence of Zoysia species, we generated a high-quality draft sequence of the genome of Z. japonica accession 'Nagirizaki' (334 Mb) in which 59,271 protein-coding genes were predicted. In parallel, draft genome sequences of Z. matrella 'Wakaba' and Z. pacifica 'Zanpa' were also generated for comparative analyses. To investigate the genetic diversity among the Zoysia species, genome sequence reads of three additional accessions, Z. japonica 'Kyoto', Z. japonica 'Miyagi' and Z. matrella 'Chiba Fair Green', were accumulated, and aligned against the reference genome of 'Nagirizaki' along with those from 'Wakaba' and 'Zanpa'. As a result, we detected 7,424,163 single-nucleotide polymorphisms and 852,488 short indels among these species. The information obtained in this study will be valuable for basic studies on zoysiagrass evolution and genetics as well as for the breeding of zoysiagrasses, and is made available in the 'Zoysia Genome Database' at http://zoysia.kazusa.or.jp.
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Determination of Genome Size, Chromosome Number, and Genetic Variation Using Inter-Simple Sequence Repeat Markers in Lotus app. Reviewed
Hidenori Tanaka, Awatsaya Chotekajorn, Sayumi Kai, Genki Ishigaki, Masatsugu Hashiguchi, Ryo Akashi
CYTOLOGIA 81 ( 1 ) 95 - 102 2016.3
Language：English Publishing type：Research paper (scientific journal)
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Monda K., Araki H., Kuhara S., Ishigaki G., Akashi R., Negi J., Kojima M., Sakakibara H., Takahashi S., Hashimoto-Sugimoto M., Goto N., Iba K.
Plant Physiology 170 ( 3 ) 1435 - 1444 2016.3
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Plant Physiology
© 2016 American Society of Plant Biologists. All Rights Reserved. The rate of gas exchange in plants is regulated mainly by stomatal size and density. Generally, higher densities of smaller stomata are advantageous for gas exchange; however, it is unclear what the effect of an extraordinary change in stomatal size might have on a plant’s gas-exchange capacity. We investigated the stomatal responses to CO2 concentration changes among 374 Arabidopsis (Arabidopsis thaliana) ecotypes and discovered that Mechtshausen (Me-0), a natural tetraploid ecotype, has significantly larger stomata and can achieve a high stomatal conductance. We surmised that the cause of the increased stomatal conductance is tetraploidization; however, the stomatal conductance of another tetraploid accession, tetraploid Columbia (Col), was not as high as that in Me-0. One difference between these two accessions was the size of their stomatal apertures. Analyses of abscisic acid sensitivity, ion balance, and gene expression profiles suggested that physiological or genetic factors restrict the stomatal opening in tetraploid Col but not in Me-0. Our results show that Me-0 overcomes the handicap of stomatal opening that is typical for tetraploids and achieves higher stomatal conductance compared with the closely related tetraploid Col on account of larger stomatal apertures. This study provides evidence for whether larger stomatal size in tetraploids of higher plants can improve stomatal conductance.
DOI： 10.1104/pp.15.01450
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NDF Digestibility Characteristics Accompanied with Developmental Stages in Some Tropical Grasses
Kyouhei Ninomiya, Naomi Yoshioka, Naoki Honda, Genki Ishigaki, Ikuo Kobayashi, Kiichi Fukuyama
Journal of Warm Regional Society of Animal Science 59 ( 1 ) 1 - 7 2016.3
Language：Japanese Publishing type：Research paper (scientific journal)
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Efficient nursery production and multiple-shoot clumps formation shoot tiller-derived shoot apices of dwarf napiergrass (Pennisetum purpureum). Reviewed
Nafiatul U, Gondo T, Ishigaki G, Mohammad R, Akashi R
Journal of Warm Regional Society of Animal Science 55 121 - 127 2016.1
Language：English Publishing type：Research paper (scientific journal)
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Nitthaisong P., Ishigaki G., Tanaka H., Akashi R.
Crop Science 56 ( 1 ) 312 - 321 2016.1
Language：English Publishing type：Research paper (scientific journal) Publisher：Crop Science
© Crop Science Society of America. All rights reserved. The genus Brachiaria contains approximately 100 identified species, including economically important tropical grasses; however, there is not much accessible information about the genetics or genomes of the genus. In this study, we determined the chromosome number and genome size by cytological analysis and flow cytometry, respectively, and estimated the molecular variability using intersimple sequence repeat (ISSR) markers for 28 accessions representing 11 Brachiaria species. The chromosome number of 10 species agreed with previous reports, and the chromosome number for B. xantholeuca was evaluated (2n = 4x = 36) for the first time. Genome size expressed as C values differed among these species (0.89 to 4.02 pg/2C) and increased with increasing ploidy levels. In contrast, the genome size given as a Cx value tended to decrease with increasing ploidy levels in polyploid plants. A total of 441 ISSR fragments were generated with 10 primers to assess the molecular variability of Brachiaria species. All 11 Brachiaria species clustered into three groups with the neighbor-joining (NJ) method. We found no correlation between the clusters and the region from where the plants were collected. Nevertheless, the clustering of accessions was clearly correlated with ploidy level and reproductive mode (sexual and apomictic) except for a few accessions. Furthermore, evolution of the Brachiaria genome and genetic diversity within the genus were discussed.
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Chromosome Number, Genomic Variation, and Molecular Markers to Assess Genetic Diversity of Brachiaria Species Reviewed
Pattama Nitthaisong, Genki Ishigaki, Hidenori Tanaka, Ryo Akashi
Crop Science 56 312 - 321 2015.12
Language：English Publishing type：Research paper (scientific journal)
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Ishigaki G., Gondo T., Rahman M., Umami N., Akashi R.
Grassland Science 60 ( 1 ) 24 - 30 2014.3
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Grassland Science
Ruzigrass (Brachiaria ruziziensis Germain et Everard cv. Kennedy) is an important forage grass in tropical and sub-tropical areas. Previously, we reported transgenic ruzigrass plants generated by our transformation system were sterile and tetraploid in spite of beginning with diploid plants. This study analyzed ploidy variation in embryogenic calli and the regenerants of diploid ruzigrass. The morphological traits and fertility were also investigated to develop a methodology for the production of stable transgenic lines. Embryogenic calli at different stages (2, 4, 6 and 12-month-old) were regenerated via somatic embryogenesis. An approach of flow cytometry (FCM) analysis was used to determine the ploidy level of embryogenic calli and regenerants of ruzigrass. FCM analysis revealed that embryogenic calli were spontaneously reduplicated at a high frequency and resulting regenerants were polyploids (tetraploid or octoploid), including 15 tetraploid regenerants (68%) and seven octoploid regenerants (32%) derived from 12-month-old embryogenic calli. These regenerants exhibited the morphological variations among different ploidy levels. The viability of pollen grains was significantly (P < 0.01) decreased in tetraploid and octoploid regenerants. Our findings indicated that clarification and resolution of ploidy variation in ruzigrass combined with ploidy level checking using FCM analysis before transformation steps is crucial for plant regeneration in transformed ruzigrass. © 2014 Japanese Society of Grassland Science.
DOI： 10.1111/grs.12040
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Muguerza M., Gondo T., Ishigaki G., Akashi R.
Asian Journal of Plant Sciences 13 ( 1 ) 8 - 17 2014
Language：English Publishing type：Research paper (scientific journal) Publisher：Asian Journal of Plant Sciences
Lignin is generally known as one of the major impediments for utilizing the potential of many forage plants because it limits digestibility and concomitantly, livestock productivity. Warm-season grasses yield high biomass but the digestibility is low due to their high lignin content. Cinnamyl alcohol dehydrogenase, a key enzyme that catalyzes the last stage in the lignin biosynthesis pathway, has been genetically altered in few grasses to increase their digestibility and forage quality. The aim of this study was to reduce the lignin content in a warm-season grass, bahiagrass (Paspalum notatum Flügge), by suppression of cinnamyl alcohol dehydrogenase gene expression. Using particle bombardment, cinnamyl alcohol dehydrogenase gene constructs with the antisense and RNAi vector under the control of the maize ubiquitin promoter were introduced into bahiagrass calli. The lignin content in most of the transgenic lines was significantly reduced, although the agronomic characteristics (plant height, leaf length, leaf width, tiller number, heading tiller and dry matter) differed between individuals. The in vitro dry matter digestibility of four of the nine transgenic plant significantly increased by 5.6-10.4% units. These results suggest that the molecular modification of the cinnamyl alcohol dehydrogenase gene function in the monolignol pathway significantly improved the feeding characteristics of the bahiagrass and that this approach could be used to improve the forage quality of other warm-season grasses. By utilizing their potential, novel cultivars could be developed that are amenable for intensified and sustainable grass forage production. © 2014 Asian Network for Scientific Information.
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Fertile transgenic Brachiaria ruziziensis (ruzigrass) plants by particle bombardment of tetraploidized callus Reviewed
Ishigaki G, Gondo T, Suenaga K, Akashi R
Journal of Plant Physiology 169 546 - 549 2012.6
Language：English Publishing type：Research paper (scientific journal)
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わい性ネピアグラスにおける腋芽生長点からの多芽体形成と効率的な苗生産 Reviewed
Nafiatul UMAMI, 権藤 崇裕, 石垣 元気, Mohammad Mijanur RAHMAN, 明石 良
日本暖地畜産学会報 55 ( 2 ) 121 - 127 2012
Language：English Publishing type：Research paper (scientific journal) Publisher：Warm Regional Society of Animal Science, Japan
本研究は，わい性ネピアグラスにおける効率的な苗生産を行うための組織培養法の改善を図り，また，苗生産において重要な課題である順化の効率化やソマクローナル変異の誘発などの問題を軽減したものである．外植体として用いた腋芽は，分げつから無菌的に摘出して，2,4-DおよびBAPを組み合わせて添加したMS固形培地で多芽体を誘導した．その結果，多芽体は0.1 mg L<sup>-1 </sup>2,4-Dおよび2.0 mg L<sup>-1 </sup>BAP添加の培地で29%と最も高い誘導率を示した．培養培地への硫酸銅の添加は，多芽体の増殖率を向上し，50 μMの硫酸銅の添加が増殖に最も有効であった．増殖した多芽体は，0.1 mg L<sup>-1 </sup>NAAおよび2.0 mg L<sup>-1 </sup>BAP添加のMS固形培地で84％と最も高い再分化率を示し，多くの植物体が再分化した．また，再分化植物体の全ては順化することができ，土壌中で旺盛に生長した．再分化植物体および栄養苗から生長させた植物体について形態を調査したところ，組織培養による形態的な変異は認められず，両者間に統計的な有意差（5％水準）はなかった．また，フローサイトメーターによる倍数性の調査では，再分化植物体における染色体数の倍加は認められなかった．以上のことから，本研究で改良した培養法により，わい性ネピアグラスの高品質な苗生産技術を確立できたものと判断した．
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Nishiwaki A., Mizuguti A., Kuwabara S., Toma Y., Ishigaki G., Miyashita T., Yamada T., Matuura H., Yamaguchi S., Lane Rayburn A., Akashi R., Ryan Stewart J.
American Journal of Botany 98 ( 1 ) 154 - 159 2011.1
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：American Journal of Botany
Premise of the study: Looming petroleum shortages and projected negative impacts of human-induced climate change may be partly alleviated by the development and use of bioenergy feedstock crops. Miscanthus × giganteus, a highly productive sterile triploid hybrid grass that was discovered in Japan several decades ago, has considerable potential as an alternative source of energy. Given the risks, however, involved in the reliance upon production of one clone of this hybrid, which is a natural cross between Miscanthus sacchariflorus and Miscanthus sinensis, for lignocellulosic bioenergy production, natural occurrences of triploidy were investigated in sympatric populations of tetraploid M. sacchariflorus and diploid M. sinensis in Japan. Methods: Seeds were counted and DNA content was estimated by flow cytometry for plants of M. sacchariflorus and M. sinensis in several sympatric populations throughout Japan. Chromosomes were also counted for select plants. Key results: Based on seed-set data, M. sacchariflorus has significantly lower seed set than M. sinensis in Japan. Putative triploid seeds were found on M. sacchariflorus plants in southern Japan. Conclusions: This is the first report of the natural occurrence of Miscanthus triploid plants in several decades. If found to be sterile and similar in productivity to the commonly cultivated clone of M. × giganteus, these triploid plants might serve as additional sources of genetic variation for bioenergy production. Seed set data also indicates that other triploid plants might be found in more northern regions of Japan. © 2011 Botanical Society of America.
DOI： 10.3732/ajb.1000258
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Estimation of genome size in Brachiaria species Reviewed
Ishigaki G, Gondo T, Ebina M, Suenaga K, Akashi R
Grassland Science 56 ( 4 ) 240 - 242 2010.12
Language：English Publishing type：Research paper (scientific journal)
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Ishigaki Genki, Gondo Takahiro, Suenaga Kazuhiro, AKASHI Ryo
Grassland science 55 ( 3 ) 164 - 170 2009.9
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japanese Society of Grassland Science
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Ishigaki G., Gondo T., Suenaga K., Akashi R.
Grassland Science 55 ( 1 ) 46 - 51 2009.8
Authorship：Lead author Language：English Publishing type：Research paper (scientific journal) Publisher：Grassland Science
We have established a plant regeneration system via multiple shoot formation, or somatic embryogenesis from seed-derived shoot apical meristems of ruzigrass (Brachiaria ruziziensis). Shoot apices as initial explants were isolated from aseptically germinated seedlings, and cultured in vitro. The most effective treatments for multiple shoots and embryogenic calli formation were 0.5 mg L-1 2,4-dichlorophnoxyacetic acid (2,4-D) plus 2.0 mg L-1 6-benzylaminopurine (BAP) and 4.0 mg L-1 2,4-D plus 0.2 mg L-1 BAP, respectively. Plant regeneration from multiple shoot-clumps was achieved by culturing on solid MS medium containing 1.0 mg L-1 BAP or 2.0 mg L-1 kinetin plus 2.0 mg L-1 gibberellic acid. Somatic embryos regenerated plantlets on a MS medium without plant hormones. Regenerated shoots were germinated precociously on MS medium containing 0.01 or 0.1 mg L-1 naphthalene acetic acid and 2.0 mg L-1 BAP. All regenerants were successfully grown up to maturity. The plant regeneration via multiple-shoot clumps and embryogenic calli formation can be used as an alternative regenerable target tissue for genetic transformation using particle bombardment of ruzigrass. © Journal Compilation © 2009 Japanese Society of Grassland Science.