Kyushu University Academic Staff Educational and Research Activities Database
List of Presentations
Takeo Yamakawa Last modified date:2019.07.26

Associate Professor / Molecular Biosciences / Department of Bioscience and Biotechnology / Faculty of Agriculture


Presentations
1. Kyi Moe, Seinn Moh Moh, 山川 武夫, Effects of organic fertilizer as EMN (estimated mineralizable nitrogen) on yields and nutrient use efficiencies of rice varieties., 第15日韓合同国際シンポジウム(AFELiSA), 2018.11, Previous studies have rarely concerned organic fertilizer application depending on EMN (estimated mineralizable N) on nitrogen (N), phosphorus (P) and potssium (K) recovery and use efficiencies and yield of Manawthukha (Indica) and Genkitsukushi (Japonica) rice varieties. In a field experiment, six treatments were used: no N fertilizer (N0), 50% of chemical fertilizer (CF50) and 100%CF (CF100), 50%CF + 50% EMN of each type of poultry manure (PM) or cow manure (CM) or compost (CP). The CF100 was equivalent to a rate of N 85 kg ha–1. The CF treatments received 60 kg P2O5 ha–1 and 85 kg K2O ha–1. The P and K applied from organic fertilizer were not adjusted. We applied organic fertilizers as EMN based on their total N content (Nishio 2007). Compared to the CF100 treatment, the CF50PM50 (total N  4%) increased N recovery efficiency (N-RE) by 12.8% in Manawthukha and 13.67% in Genkitsukushi, and yields by 9.5% in Manawthukha and 8.33% in Genkitsukushi. The N, P and K uptake (NPK-U) were maximized by CF50PM50 at the critical growth stages of both varieties. The CF50PM50 had significantly higher N use efficiency (NUE) than the CF100, CF50CM and CF50CP, accounting for 81.19 in Manawthukha and 93.29 in Genkitsukushi. Comparison with the CF100 treatment, the EMN of PM50 plus CF50 increased agronomic N use efficiency (AUE) by 19.89% in Manawthukha, and 8.92% in Genkitsukushi. The Genkitsukushi had higher N harvest index (NHI) than the Manawthukha, whereas NU in grain was lower compared to total NU. Among manure, the higher NREs derived from manure (N-REdfM) were observed 58.19% and 59.31% in the PM (total N  4%) of both varieties. The CM and CP (total N  2%) showed the lower NU, NRE, N-REdfM, NUE and AUE. In fact, the EMN by organic fertilizers supplied enough nutrients to rice varieties, showing similar yields to CF100. Based on results, a manure or an organic fertilizer with total N ( 4%) was more compatible with EMN method, enhanced yields through the higher NPK-U, NPK-RE, N-REdfM, NUE and AUE of Manawthukha and Genkitsukushi rice varieties, comparable with solo basal CF..
2. Aung Zaw Htwe, 山川 武夫, Effects of co-inoculation of Bradyrhizobium japonicum SAY3-7 and Streptomyces griseoflavus P4 on plant growth, nodulation, nitrogen fixation, nutrient uptake and seed yield of soybean., 第15日韓合同国際シンポジウム(AFELiSA), 2018.11, Soybeans, in symbiosis with Bradyrhizobium, have the ability to fix nitrogen at a rate of up to 300 kg N ha-1 under favorable conditions (Smith and Hume 1987). However, the symbiosis is dependent on host specificity. This specificity might also be related to the nodulation regulatory genes of soybean cultivars and nodulation types of rhizobia, especially in the soybean. Ishizuka et al. (1991a; 1991b) tested the compatibility and preference of Rj-genotype soybean cultivars with specific Bradyrhizobium strains. The Bradyrhizobium strains are classified into nodulation types A, B, and C, based on their compatibility with Rj cultivars. Type A strains are preferred by the non-Rj genotype soybean cultivars and nodulate with all the Rj-genotype soybean cultivars. Type B strains are preferred by Rj4 genotype soybean cultivars and inhibit nodulation with the Rj2Rj3 genotype soybean cultivars. Type C strains are preferred by the Rj2Rj3 cultivars and restrict effective nodule formation with the Rj4 genotype soybean cultivars. Therefroe, this experiment was conducted to select the most effective type A and type B strains for specific Rj-gene harboring soybean varieties and to test the symbiotic effectiveness of selected strains on non-Rj and Rj4 soybean varieties.
Screening experiments of Myanmar Indigenous Bradyrhizobium strians were done using the specific soybean varieties in the Phytotron (controlled-environmental condition), Kyushu University, Japan. For inoculation preparation, Bradyrhizobium strains were cultured in A1E liquid media (Kuykendall 1987) on a rotary shaker (100 rpm) at 30°C for 7 days. For pot preparation and cultivation, the 1 L pots were filled with vermiculite and 0.6 L of half-strength modified Hoagland nutrient (MHN) solution (Nakano et al. 1997). The pots were autoclaved at 120°C for 20 min. Five surface sterilized seeds were sown in the pots. For inoculation, the liquid bacterial cultures were diluted with sterilized MHN solution to 107 cells mL-1. Each seed was inoculated with 5 mL of bacterial suspension. The plants were cultivated in an environmentally controlled room (25°C and 75% relative humidity) for 30 days. At the harvest time, N fixation was analyzed. Then, nodules were counted. Shoots, roots and nodules were collected separately and oven dried at 70°C for 24 hours to record dry weights. After the screening experiment, a pot experiment was conducted to evaluate the selected strain in soil condition.
In the first screening experiment, type A and type B strains with higher nitrogen fixation and proper nodulation on their respective soybean cultivars were selected for the next screening. In the second screening, B. elkanii AHY3-1 (type A), B. japonicum SAY3-7 (type A), B. elkanii BLY3-8 (type B) and B. japonicum SAY3-10 (type B) isolates, which showed higher nitrogen fixation and nodulation in Yezin-3 (Rj4) and Yezin-6 (non-Rj), were selected for the next experiment. In the third screening experiment, SAY3-7 and BLY3-8, which had higher nitrogen fixing potential and proper nodulation, were selected as effective isolates. SAY3-7 and BLY3-8 were tested for their symbiotic efficacy in Futsukaichi soil. This study shows that inoculation treatment of SAY3-7 and BLY3-8 significantly increased plant growth, nodulation, and N fixation at the V6 and R3.5 in Yezin-3 (Rj4) and/or Yezin-6 (non-Rj), and the seed yield at R8 stage, in both soybean varieties compared with the control treatment. It can be concluded that SAY3-7 and BLY3-8 are suitable for inoculant production because of their higher nitrogen fixation ability, proper nodulation and better productivity of Myanmar soybean cultivars..
3. Kyi Moe, Seinn Moh Moh, 山川 武夫, Effect of combined organic and inorganic fertilizer on growth and productivity of Komatsuna (Brassica rapa L. var. wakana komatsuna), 日本土壌肥料学会九州支部秋季例会, 2017.09, Objectives: This study was conducted to investigate the effect of combined organic and inorganic fertilizers on the growth and productivity of Komatsuna (Brassica rapa L. var. wakana komatsuna).
Materials and Methods: The three levels of chemical fertilizers (CF) and different combinations of organic manures and inorganic fertilizers were assigned in the randomized complete block design (RCB) with three replications. In this study, three types of poultry manures (PM); (1) ekono hakkou keifun (PME), (2) hakkou keifun (PMH), (3) keifun (PMK) and three types of cow manures (CM); (1) neobi-ru (CMN), (2) gyufun (CMG), (3) hakkou gyufun taihi (CMH) were used as tested manures. The standard rate of chemical fertilizer (100%CF) is 0.5 g NPK (as (NH4)2SO4) and 0.5 g P2O5 (as KH2PO4) and 0.5 g K2O (as K2HPO4) pot-1. The amount of N applied was calculated from estimated mineralizable N (%) based on total N of each manure according to Nishio (2007). Pots without organic and inorganic fertilizers was used as control (NPK0).
Results: There were significant differences in growth parameters and dry matter (DM) among CF levels as well as different combinations of organic and inorganic fertilizers. As the number of leaf plant-1 and leaf length, the higher values were found in CF+PMK combinations, the maximum one in 100% CF+100% PMK. The CMG also provided the higher growth parameters as next to PMK. The 150% CF produced the lower number of leaf, while it obtained the maximum SPAD values and leaf length. Significantly, the plants of 50% CF showed severe N deficiency symptom showing slow growth. The PMK gave the higher DM combined with CF, especially the highest DM in 50% CF+100% PMK. The 150% CF resulted the lower DM than all CF+PMK combinations but got the higher DM than 100% and 50% CF. In combinations with CF, the CMG also has a good performance showing the higher DM than 150% CF. As a virgin soil, the Futsukaichi soil has low fertility observing the lowest growth of plants in the control.
Conclusion: This study suggested that combined use of organic and inorganic fertilizers was effective for enhancing the growth of Komatsuna as well as reducing the chemical fertilizers dose.
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4. Doan Cong Dien, 山川 武夫, Screening for Cold Tolerance in Rice (Oryza sativa L.) at Germination Stage., 日本土壌肥料学会九州支部秋季例会, 2017.09, 〔Objective〕 This study was conducted in order to verify the effect of cold stress condition to rice at germination stage, and to select some cold tolerant rice varieties for further studies.
〔Materials and Methods〕 In this study, 186 rice varieties were used for a screening from April to May, 2016. Seeds of experimental varieties were germinated in a growth chamber under two conditions: 21 days in 13°C (cold stress) and seven days in 25°C (control). The number of germinated seeds was counted daily until 21 days after sowing in cold stress and 7 days after sowing in control. The germination index (GI %) was calculated by the following formula (Farzin et al., 2013): GI % = (G14 + G21)/ 10 x 100; where G14 and G21 are number of germinated seeds at 14 and 21 days after sowing, respectively; 10 is total seed number per rice variety. Coleoptile and radicle length (mm) of germinated seeds were obtained at 21 days after sowing in cold stress and at 7 days after sowing in control. Reduction percentage in coleoptile and radicle length under cold stress in comparison with control condition were calculated also.
〔Results〕 There was a large variation in germination index between varieties. Germination ability was severely affected by cold stress. Only 14 varieties showed the germination index higher than 50%, in which Tumo-Tumo expressed the highest germination index (95%) compared to other varieties. Low temperature significantly depressed the growing of coleoptile and radicle in rice varieties. The average reduction ratios in coleoptile length and radicle length under cold stress condition compared to control were 97.68% and 96.78%, respectively. Gompa 2 expressed the lowest reduction ratio for coleoptile length (94.07%) while Heichiao-chuili-hsiang-keng showed the lowest reduction ratio for radicle length (81.37%) among experimental varieties. Compared to other varieties, ARC 13829 variety retained the longest coleoptile length (8.40 mm) and radicle length (14.20 mm) under cold stress condition.
〔Conclusion〕 Tumo-Tumo, Gompa 2, Heichiao-chuili-hsiang-keng and ARC 13829 varieties were selected as cold tolerant varieties at germination stage and will be used for further experiment.
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5. Thieu Thi Phong Thu, Yasui Hideshi, 山川 武夫, Rice accessions response differently to salt stress with various mineral contents in roots, sheaths and leaves of seedling., ISSAAS (International Society for Southeast Asian Agricultural Science) International Congress, 2017.10, In order to determine the useful salt stress level for screening salt tolerance in rice at young seedling stage under growth chamber condition, this experiment was conducted to compare the responses of 2 varieties of KD18 (sensitive) and KKX (tolerance) against 4 different salt stress levels in mineral content of leaf sheath. After 3 days germination, germinated seeds were grown for 14 days on Yoshida hydroponic solution. Then, artificial sea water was used for stress treatments which were controlled at 2, 4 and 6 dS m-1 EC during 2 weeks. Seedlings which were continued growing on Yoshida solution as control treatment (Y) until the end of experiment. This experiment was carried out in growth chamber at 25oC temperature and 16 hours light and 8 hours dark regime. After two-week period of salt stress, shoot and root were measured for length before plant was cut into shoot and root. After oven drying, shoots was divided into sheaths and leaves, then sheath were cut into small pieces, which used for mineral content determination. The K, Na, Mg and Ca contents were determined by HNO3 digestion method, and followed by atomic absorption spectrophotometer (Z5300, Hitachi).
The sheath K contents decreased when EC levels increased in both varieties. The significant differences in sheath K content between 2 varieties were not obsevered at Y and 2 dS m-1EC, but obsevered at 4 and 6 dS m-1 EC. Those sheath K contents were higher in salt tolerant variety KKX than sensitive variety KD18. The largest difference between two varietes in sheath K content was obsevered at EC 4 dS m-1. In contrast to sheath K content, the sheath Na contents increased when EC levels increased in both rice varieties. The sheath Na contents of two varieties were not different in control treatment. KKX showed significantly lower sheath Na contents in compare with KD18 at 2, 4, 6 dS m-1 EC treatments. The most significant difference of sheath Na content was seen at 4 dS m-1 EC treatment. Mg contents was also expressed as the same with sheath Na contents, but the significant difference was not observerd at 6 dS m-1 EC treatment. Sheath Ca content between 2 varieties were not different in Y and 2 dS m-1 EC treatments, but significantly different in 4 and 6 dS m-1 EC treatments. Salt tolerant variety KKX had significant lower sheath Ca contents than salt sensitive varietiy KD18. The Na/K ratios and Mg/K ratios also were not different in Y and 2 dS m-1 EC treatments, but significant different in 4 and 6 dS m-1 EC treatments. The most clearly difference of these ratios between 2 varieties were at 4 dS m-1 EC treatment. Salt tolerant variety KKX had significant lower ratios than salt sensitive varietiy KD18.
From the results, the 4 dS m-1 EC level was suggested as a good level of salt stress for screening salt tolerance in rice at young seedling stage under growth chamber condition. This salt stress level shows the clearest differences between 2 varieties of not only the sheath K, Na, Mg and Ca contents but also the sheath Na/K and the sheath Mg/K ratios..
6. Aung Zaw Htwe, Seinn Moh Moh, Kyi Moe, 山川 武夫, Effects of co-inoculation of Bradyrhizobium japonicum SAY3-7 and Streptomyces griseoflavus P4 on plant growth, nodulation, nitrogen fixation, nutrient uptake and seed yield of soybean., 第14日韓合同国際シンポジウム(AFELiSA), 2017.11, Nowadays, co-inoculation of nitrogen fixing bacteria with plant growth promoting bacteria has become more popular than a sole inoculation of rhizobia or plant growth promoting bacteria because co-inoculation increases soybean yield and improves sustainability of agriculture (Hungria et al., 2015). Many researchers have reported that co-inoculation of rhizobia with plant growth promoting bacteria improve nodulation and nitrogen fixation (Li and Alexander, 1988; Vessey and Buss, 2002; Figueiredo et al. 2007). It has been reported that co-inoculation of bradyrhizobia with endophytic bacteria S. griseoflavus P4 showed the beneficial effects on N fixation in various soybean cultivars under the green house, environmentally controlled condition and open field condition (Soe et al., 2012; Soe and Yamakawa, 2013a; 2013b). Therefore, this study was conducted to investigate effects of co-inoculation of B. japonicum SAY3-7 and S. griseoflavus P4 on plant growth, nodulation, nitrogen fixation, nutrients accumulation and seed yield of Yezin-6 soybean cultivar.
The experiment was conducted at Kyushu University Farm, Fukuoka Prefecture, Japan (33°37' N, 130°25' E), from July to November 2016. In this study, randomized completely block design was used with three replications. Treatments were an uninoculated control (Control), a single inoculation with S. griseoflavus P4 (P4), a single inoculation of B. japonicum SAY3-7 (SAY3-7), and a co-inoculation of SAY3-7 and P4 (P4 + SAY3-7). Plant samples were collected from five different growth stages: V6 (six unfolded trifoliate leaves), R2 (Full flowering stage), R3.5 (early pod-fill stage) and R5.5 (early seed-fill stage), and R8 (maturity stage). In this study, nitrogen fixations were measured using the acetylene reduction assay (ARA) and ureide methods. After digestion of the nutrients using the H2SO4-H2O digestion method (Ohyama et al. 1991), total N accumulation in the shoot was measured by the indophenol method (Cataldo et al. 1974); total P was analyzed using the ascorbic acid method (Murphy and Riley 1962); and total K, Ca, and Mg were measured using atomic absorption spectrophotometry (Z-5300, Hitachi, Tokyo, Japan).
This study shows that a significant increase in plant growth, nodulation, nitrogen fixation, N, P, K, Ca, and Mg uptakes, yield related parameters and yield was occurred due to the single inoculation of B. japonicum SAY3-7, indicating that SAY3-7 is an effective nitrogen fixing bacterium and had the ability to compete with native bradyrhizobia. Moreover, the result findings of this study highlight that single inoculation of S. griseoflavus P4 had the ability to improve plant growth, nodulation, nitrogen fixation and seed yield compared with control. These indicate that S. griseoflavus P4 is an effective endophytic actinomycete for plant growth, nodulation and nitrogen fixation. Consequently, co-inoculation of SAY3-7 and P4 significantly improved nodule mass; nodule dry weight; shoot and root biomass; N fixation; N, P, K, Ca, and Mg uptake; and seed yield in “Yezin-6” compared with the control and single inoculation treatments. Therefore, combined use of SAY3-7 and P4 will be helpful for soybean production through enhancing plant growth, nodulation, nitrogen fixation and other major nutrient uptakes.
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7. Kyi Moe, Sein Moh Moh, 山川 武夫, Integrated effect of organic and inorganic fertilizers on NPK uptakes and recovery efficiencies, and productivity of Komatsuna (Brassica rapa L. var. wakana komatsuna)., 第14日韓合同国際シンポジウム(AFELiSA), 2017.11, This study was investigated the effect of integrated organic and inorganic fertilizers on NPK uptakes and recovery efficiencies (NPK-RE), and productivity of Komatsuna (Brassica rapa L. var. wakana komatsuna).
The randomized complete block design (RCB) was laid out with three replications. Three types of poultry manures (PM); ekono hakkou keifun (PME), hakkou keifun (PMH), keifun (PMK) and three types of cow manures (CM); neobi-ru (CMN), gyufun (CMG), hakkou gyufun taihi (CMH) were integrated with various levels of chemical fertilizer (CF). The integrated treatments are 14 treatments; 50%CF, 100%CF, 150%CF, 100%CF+50%PMH, 100%CF+50%PMK, 100%CF+50%PME, 100%CF+50%CMG, 100%CF+50%CMN, 100%CF+50%CMH, 50%CF+100%PMH, 50%CF+100%PMK, 50%CF+100%PME, 50%CF+100%CMG, 50%CF+100%CMN, 50%CF+100%CMH. The standard rate of chemical fertilizer (100%CF) is 0.5 g NPK (as (NH4)2SO4) and 0.5 g P2O5 (as KH2PO4) and 0.5 g K2O (as K2HPO4) pot-1. The amount of N applied was calculated from total N and estimated mineralizable N (%) of each manure according to Nishio (2007). Pot without organic and inorganic fertilizers was used as control (NPK 0).
Significant differences were observed in dry matter (DM), NPK uptakes, and NPK-RE (%) affected by CF levels as well as integration of organic and inorganic fertilizers. With the same rate 150%NPK applied, the N, P, Mg and Ca uptakes of (CF+PMK)s integrations were higher than those of 150% CF as well as (CF+CM)s. However, the 100%CF+50%CMN was maximized the K uptake which was similar to those of CF+PMs. On the low fertility of futsukaichi soil, the 100%CF could not provide enough NPK for Komatsuna, showing lower DM. The 100%CF+50%PMs produced the highest DM than 150%CF and 100%CF+CMs. On applying 150% NPK, the maximum NP-RE (%) was also observed in the 100%CF+50%PMK and K-RE (%) in 50%CF+100%PMK, followed by 150%CF and 100%CF. The sole application of chemical fertilizer resulted low NPK-RE(%) in 50%CF, 100%CF and 150%CF. Obviously, the PMK has a great potential for integration of chemical fertilizers while creating higher DM, NPK uptakes and NPK-RE(%).
This study clarify that integrated use of organic and inorganic fertilizers was effectively enhanced the growth, NPK uptakes and recovery efficiency of Komatsuna as well as created the opportunity for reducing the CF usage.
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8. Seinn Moh Moh, Kyi Moe, Aung Zaw Htwe, Yasumasa Obo, 山川 武夫, Effects of fermented sea weed liquid fertilizers on plant growth characteristics and mineral contents of Komatsuna (Brassica rapa L. var. wakana komatsuna)., 第14日韓合同国際シンポジウム(AFELiSA), 2017.11, Seaweeds or macro algae are aquatic plants belonging to the thallophyta of plant kingdom. Seaweeds are rich in minerals, protein, lipid, carbohydrate, vitamins, bromine, iodine etc. In recent years, seaweed extracts as liquid fertilizers have come in market (Divya. and Reddi, 2017). Seaweeds have recently gained importance as foliar sprays for several crops (Thivy, 1961; Metha et al., 1967; Bokil et al., 1974) because the extract contains growth promoting hormones (IAA and IBA), cytokinins, trace elements, vitamins and amino acids (Challen and Hemingway, 1965). The objective of this study is to observe the effect of basal and foliar application of seaweed fermented liquid fertilizer on the plant growth, dry matter accumulation (DMA) and N, P, K, Na, Ca and Mg contents of Komatsuna (Brassica rapa L. var. wakana komatsuna).
Three kinds of pot experiments were conducted at Kyushu University’s Phytoton (25°C and 75% RH), which contain one liter of vermiculite and different types of liquid fertilizer. Expt. 1 was used 4 types of seaweed fermented liquid fertilizers (SLFs; SLF1 (anaerobic) and SLF2 (aerobic) using non-washed Nori (Pyropia yezoensis) and SLF3 (anaerobic) and SLF4 (aerobic) using washed Nori) and Hoagland solution as control (6 treat.). All liquid fertilizers were adjusted total N and K to 7.5 mM and 3 mM, respectively. Expt. 2 was performed the basal and foliar application of SLFs (10 treat.). The concentration of inorganic N and K of 1/2 strength Hoagland solution and SLFs were adjusted to 5 and 3 mM by addition of NH4NO3, respectively. Expt. 3 was tested only the effects of foliar application of 10, 20, 50 times dilution of SLFs in 5 days interval (13 treat.). The 1/4 strength of Hoagland solution added 2.5 mM of NaNO3 was used as liquid fertilizer. All experiments were arranged by the completely randomized design with 3 replications. Growth parameters and SPAD value were recorded 3 days interval. After 35 days, the plant parts (shoot and root) in all experiments were harvested by cutting at the cotyledon node. For N and P contents in plant parts were analyzed by using salicylic acid-H2SO4-H2O2 digestion method (Ohyama et al. 1991), and N determination by Indophenol method (Cataldo et al., 1974), P determination by ascorbic acid method (Murphy and Riley 1962). K, Na, Ca and Mg contents were analyzed by nitric acid digestion method and Atomic absorption spectrophotometer (Z-5300, Hitachi).
In Expt. 1 and 2, plant growth and DMA of SLFs application were depressed compered with Hoagland solution. Furthermore, the color of all plants leaves applied SLFs become dark color and those SPAD value is higher than the Hoagland solution treatment. The reason was derived from P deficiency in all SLFs treatments, because the P contents in plants treated by SLFs were severely low. In Expt. 2, the application of 1/2 Hoagland solution containing NH4NO3 appeared some toxic symptom in shoot parts. This result was thought to reflect the application of NH4NO3. In Expt. 3, there was no toxic symptom occur, because of low concentration of nutrients and use of NaNO3. There were no significantly differences in nutrient contents among all foliar treatment. However, DMA of LF2 foliar application is better than other SLFs. According to the result of all experiments, the nutrients uptakes and growth of all plants by using SLFs is lower than Hoagland solution treatment. Under this experimental condition, since decomposed microorganisms are not present in the rhizosphere, it was thought that not only the organic matter was not mineralized but could not be absorbed. So, under the effective soil microorganisms in soil condition, the effectiveness of SFLs should be considered.

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9. Doan Cong Dien, 山川 武夫, Screening and selection for cold tolerance in rice (Oryza sativa L.) at seedling stage., 第14日韓合同国際シンポジウム(AFELiSA), 2017.11, Rice (Oryza sativa L.) is one of the most important staple food for half of the world population. Unlike other cereals such as wheat and barley, rice plants are susceptible to cold stress, which has negative impacts on germination, vegetative growth, and final productivity. In northern provinces of Vietnam, rice cultivation in spring season (February to June) is usually affected by low temperature at germination and seedling stages, which results in seed loss and delay in transplanting period. In this study, 175 rice varieties from different ecological regions over the world were screened under natural low temperature at seedling stage. The screening was conducted in a greenhouse of Kyushu University from November to December, 2014 in which air temperature was gradually decreased during the experiment. Cold tolerant ability of rice varieties in this screening was verified based on leaf colour scale (LCS) follow the Standard Evaluation System for Rice (IRRI, 2002): 1: Seedlings dark green; 3: Seedlings light green; 5: Seedlings yellow; 7: Seedling brown; 9: Seedlings dead. The screening found a large genotypic variation in leaf colour scale among experimental varieties (ranged from 1 to 9). There were 30 varieties scored at 1 (highly cold tolerant group - HCTG); 31 varieties scored at > 1 to 3 (moderate cold tolerant group); 21 varieties scored at >3 to 5 (cold tolerant group); 49 varieties scored at >5 to 7 (cold sensitive group); and 44 varieties scored at >7 to 9 (highly cold sensitive group - HCSG).
From the screening results, 53 varieties with different leaf colour scales were selected and used for another experiment at seedling stage. During the first week after sowing, seedlings of all varieties were nurtured at 25oC in a biotron. After that, rice seedlings were treated under 2 different conditions including natural low temperature (control) and warmed condition for 2 weeks. For warming treatment, a warming sheet was set at 25oC and put under the seedling trays. The experiment was carried out from March to April, 2015 in which natural air temperature gradually increased through the treatment time. The experimental results shown that warming treatment were significantly increased shoot length (129%), root length (127%) and shoot dry weight (142%) of rice seedlings compared to control condition. There was no significant correlation between leaf colour scale (in 2014 screening) and the warm/control ratio in parameters. This might be explained by the difference in natural low temperature between two experimental times. However, for shoot dry weight, varieties in HCTG showed the lowest warm/control ratio (1.33) while HCSG retained the highest warm/control ratio (1.54). In comparison between varieties, Domzard (LCS=1) expressed the lowest warm/control ratio (0.98) while Namsagui-19 (LCS=9) shown the highest warm/control ratio (2.40) in shoot dry weight accumulation. These suggested that using cold tolerant varieties and/or warming sheet are promising methods to overcome the negative effects of cold stress in rice at seedling stage. In addition, warming sheet is higher effective to cold sensitive varieties compared to cold tolerant varieties.
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10. Thieu Thi Phong Thu, 山川 武夫, Different salt stress affects on mineral contents in leaf sheaths of salt sensitive variety–KD18 and salt tolerant varitety- KKX., 第14日韓合同国際シンポジウム(AFELiSA), 2017.11, In order to determine the useful salt stress level for screening salt tolerance in rice at young seedling stage under growth chamber condition, this experiment was conducted to compare the responses of 2 varieties of KD18 (sensitive) and KKX (tolerance) against 4 different salt stress levels in mineral content of leaf sheath. After 3 days germination, germinated seeds were grown for 14 days on Yoshida hydroponic solution. Then, artificial sea water was used for stress treatments which were controlled at 2, 4 and 6 dS m-1 EC during 2 weeks. Seedlings which were continued growing on Yoshida solution as control treatment (Y) until the end of experiment. This experiment was carried out in growth chamber at 25oC temperature and 16 hours light and 8 hours dark regime. After two-week period of salt stress, shoot and root were measured for length before plant was cut into shoot and root. After oven drying, shoots was divided into sheaths and leaves, then sheath were cut into small pieces, which used for mineral content determination. The K, Na, Mg and Ca contents were determined by HNO3 digestion method, and followed by atomic absorption spectrophotometer (Z5300, Hitachi).
The sheath K contents decreased when EC levels increased in both varieties. The significant differences in sheath K content between 2 varieties were not obsevered at Y and 2 dS m-1EC, but obsevered at 4 and 6 dS m-1 EC. Those sheath K contents were higher in salt tolerant variety KKX than sensitive variety KD18. The largest difference between two varietes in sheath K content was obsevered at EC 4 dS m-1. In contrast to sheath K content, the sheath Na contents increased when EC levels increased in both rice varieties. The sheath Na contents of two varieties were not different in control treatment. KKX showed significantly lower sheath Na contents in compare with KD18 at 2, 4, 6 dS m-1 EC treatments. The most significant difference of sheath Na content was seen at 4 dS m-1 EC treatment. Mg contents was also expressed as the same with sheath Na contents, but the significant difference was not observerd at 6 dS m-1 EC treatment. Sheath Ca content between 2 varieties were not different in Y and 2 dS m-1 EC treatments, but significantly different in 4 and 6 dS m-1 EC treatments. Salt tolerant variety KKX had significant lower sheath Ca contents than salt sensitive varietiy KD18. The Na/K ratios and Mg/K ratios also were not different in Y and 2 dS m-1 EC treatments, but significant different in 4 and 6 dS m-1 EC treatments. The most clearly difference of these ratios between 2 varieties were at 4 dS m-1 EC treatment. Salt tolerant variety KKX had significant lower ratios than salt sensitive varietiy KD18.
From the results, the 4 dS m-1 EC level was suggested as a good level of salt stress for screening salt tolerance in rice at young seedling stage under growth chamber condition. This salt stress level shows the clearest differences between 2 varieties of not only the sheath K, Na, Mg and Ca contents but also the sheath Na/K and the sheath Mg/K ratios..
11. Thieu Thi Phong Thu, 山川 武夫, Effects of salt stress on plant growth characteristics and mineral content of diverse rice genotypes., 第13日韓合同国際シンポジウム(AFELiSA), 2016.11.
12. Doan Cong Dien, 山川 武夫, Effects of Drought to Morphological, Physiological and Biochemical Characteristics of Rice (Oryza sativa L.) at Vegetative Stage., 第13日韓合同国際シンポジウム(AFELiSA), 2016.11.
13. Aung Zaw Htwe, Hirohito Tsurumaru, Yuchi Saeki, Yu Kanesaki, Hirofumi Yoshikawa, 山川 武夫, Characterization of soybean cultivars and Bradyrhizobium strains from Myanmar., 第13日韓合同国際シンポジウム(AFELiSA), 2016.11.
14. Khem Borin, 平井 康丸, 山川 武夫, 森 裕樹, Eiji Inoue, 岡安 崇史, 光岡 宗司, Nitrogen balance in a paddy field cultivated with whole crop rice using cow manure and chemical fertilizer, システム農学会2016年度春季大会, 2016.05.
15. Aung Zaw Htwe, 山川 武夫, Low density co-inoculation of Brayrhizobium japonicum SAY3-7 and Streptomyces griseoflavus P4 promotes plant growth and nitrogen fixation in various soybean varieties, 日本土壌肥料学会全国大会, 2016.09.
16. Takeo Yamakawa, 山田 直隆, 西 幸夫, 岡本啓湖, Decontamination of radioactive cesium by stevia fermented product in Fukushima broccoli cultivation field, The 13th International Conference on Trace Elements, 2015.07.
17. Aung Zaw Htwe, 山川 武夫, Papa Saliou Sarr, Tomoyuki Sakata, Phylogenic diversity and nodulation types of indigenous bradyrhizobia isolated from five major soybean growing regions in Myanmar, 日本土壌肥料学会九州支部春期例会, 2015.04.
18. Khem Borin, 平井 康丸, 山川 武夫, 森 裕樹, Eiji Inoue, 岡安 崇史, 光岡 宗司, KEffects of manure application on growth and yield of rice for whole crop silage, 日本土壌肥料学会全国大会, 2014.09.
19. Khem Borin, 平井 康丸, 山川 武夫, 森 裕樹, Eiji Inoue, 岡安 崇史, 光岡 宗司, Nitrogen balance in the production of rice for whole crop silage, 第68回農業食料工学会九州支部例会, 2014.09.
20. Khin Myat Soe, Takeo Yamakawa, Coinoculation of B. yuanmingense MAS34 and S. griseoflavus P4 to enhance nodulation, N2 fixation and yield of soybean varieties., 18th International Congress on Nitrogen Fixation (18th ICNF), 2013.10, A field experiment was conducted to assess the coinoculation of B. yuanmingense MAS34 and S. griseoflavus P4 to enhance nodulation, N2 fixation and yield of soybean varieties. All the dry matter production, N2 fixation and seed yield were significantly influenced by the effect of inoculated strains alone (P<0.01). The variety effect was also significant (P<0.05) on nodule dry weight at V6 stage, percentage of N derived from atmosphere N2 at R3.5 stage and seed yield at maturity stage. Variety and strains interaction was detected on seed yield at maturity stage (P<0.05). The single inoculation of P4 did not show significant effects on dry matter production, N2 fixation and seed yield of all soybeans compared with uninoculated control. The dry matter production, relative ureide index, percentage of N derived from atmosphere N2 and seed yield were significantly (P<0.01) enhanced mostly by single inoculation of MAS34 and secondly by dual inoculation of P4+MAS34 in Yezin-3 and dual inoculation of P4+MAS34 in Yezin-6. .
21. KYI MOE, 山川 武夫, THIEU THI PHONG THU, Growth and yield parameters of rice variety Manawthukha affected by different application methods of nitrogen and split applications, 日本土壌肥料学会九州支部春期例会, 2013.04.
22. KYI MOE, 山川 武夫, THIEU THI PHONG THU, Effect of different application methods of nitrogen and split applications on NPK accumulations, nitrogen use efficiency of rice variety Manawthukha, 日本土壌肥料学会九州支部春期例会, 2013.04.
23. THIEU THI PHONG THU, 山川 武夫, KYI MOE, The growth parameters and seed quality of inbred and hybrid rice respond to different nitrogen application timings, 日本土壌肥料学会九州支部春期例会, 2013.04.
24. Khin Myat Soe, Takeo Yamakawa, PHYLOGENETIC DIVERSITY OF INDIGENOUS BRADYRHIZOBIA OF SOYBEAN FROM DIFFERENT AGRO-CLIMATIC REGIONS IN MYANMAR, The 2nd Asian Conference on Plant-Microbe Symbiosis and Nitrogen Fixation, 2012.10, Soybean (Glycine max L. Merr.) is the most important grain legume crop in the world and important cash crop in Myanmar. Biological nitrogen fixation is the agronomic importance in reducing the need for chemical nitrogen fertilizer for agriculturally-important crops. This study was aimed to characterize the indigenous bradyrhizobia of soybean from three different agro-climatic regions in Myanmar. In the present study, sequence analysis of the bacterial 16S-23S rRNA internal transcribed spacer (ITS) region was performed to characterize genetically 43 indigenous soybean rhizobia from three different geographic regions (Shan State: Upper Myanmar, Mandalay Region: Middle Myanmar and Yangon Region: Lower Myanmar) of Myanmar. The sequence analysis clustered all isolates in the genus Bradyrhizobium and the collected strains were conspecific with B. japonicum, B. elkanii, B. yuanmingense and Bradyrhizobium sp.. B. yuanmingense was isolated from Shan State and Yangon Region where it attained the frequency of 17% and 12%, respectively. B. japonicum was predominant at Shan State and Mandalay Region with more than 33% of the isolates. B. elkanii was mainly recorded the highest frequency of 88% to Yangon Region, 67% to Mandalay Region and 35% to Shan State. However, B. sp., MAS15 was isolated only from Shan State where it belonged to 4% of isolates. Highest genetic diversity (Shannon’s diversity index) of Bradyrhizobium strains was observed in Shan State soybean growing area. This study revealed that B. elkanii distributed throughout the soybean cultivation areas and recorded as the dominant strains in Myanmar. This is the first on the finding of B. yuanmingense from nodules of soybean and geographical distribution of indigenous bradyrhizobia of soybean from the different regions in Myanmar..
25. Khin Myat Soe, Takeo Yamakawa, EVALUATION OF NODULATION AFFINITY AMONG RJ-GENOTYPE SOYBEANS USING THE BRADYRHIZOBIAL ISOLATED FROM DIFFERENT REGIONS IN MYANMAR, The 2nd Asian Conference on Plant-Microbe Symbiosis and Nitrogen Fixation, 2012.10, Soybean (Glycine max L. Merr.) cultivars form nodules on roots by infection with Bradyrhizobium strains. However, soybean cultivars harbor nodulation conditioning genes, Rj2, Rj3 and Rj4 that ineffective nodules with some strains of Bradyrhizobium. The Bradyrhizobium strains were classified into three types based on their compatibility with Rj-genotype. Type A strains formed effective nodules with all Rj-genotype cultivars and were preferred by the non-Rj-genotype cultivars for nodulation. Type B strains that were incompatible with the Rj2Rj3-genotype were preferred by Rj4-cultivars, whereas type C strains that were incompatible with the Rj4-genotype were preferred by Rj2Rj3-cultivars. In this study, the nodulation type of indigenous bradyrhizobia of soybean on Rj-genotype cultivars was investigated using 43 bradyrhizobia isolated from three different agro-climatic regions (Shan State: Upper Myanmar, Mandalay Region: Middle Myanmar and Yangon Region: Lower Myanmar) in Myanmar. The phylogenetic trees of three different growing areas in Myanmar were constructed based on sequence analysis of the bacterial 16S-23S rRNA internal transcribed spacer (ITS) region. There were examined two nodulation types, type A and B in the Shan State where the nodulation type B was dominant. The Mandalay Region was prominently occupied by the nodulation type A, while in the Yangon Region, the isolated strains were classified as the nodulation type A, B and C. The present study revealed that there were two Rj-genotypes as Rj4- and non-Rj-genotypes among the nine soybean cultivars collected from Myanmar. These findings indicated that the compatibility between Rj4-genotypes soybeans and nodulation type B strains in Shan State and Yangon Region, but in Mandalay region, the compatibility between non-Rj-genotype soybeans and nodulation type A strains was clearly observed..
26. Khin Myat Soe, 山川 武夫, Effects of endophytic actinomycetes (Streptomyces griseoflavus, P4) on different crops and coinoculation with selected Bradyrhizobium strains, 日本土壌肥料学会九州支部秋期例会, 2012.10.
27. Khin Myat Soe, 山川 武夫, Effects of endophytic actinomycetes (Streptomyces griseoflavus, P4) on different crops and coinoculation with selected Bradyrhizobium strains, 日本土壌肥料学会九州支部秋期例会, 2012.10.
28. Papa Saliou Sarr, Shunsei Fujimoto, Takeo Yamakawa, Effect of external nitrogen concentration and light intensity on nodulation, nitrogen
fixation and growth of cowpea (Vigna unguiculata L. Walp.), XV International Congress on Molecular Plant-Microbe Interactions, 2012.07, Cowpea is a legume crop able to fix atmospheric nitrogen with soil rhizobia. The objective of this study was to investigate the concentration of external nitrogen that suppresses nodulation, and the effect of light intensity on the symbiosis and cowpea growth. In a hydroponic culture experiment, nitrogen was supplied at 0, 1, 2.5, 5, 7.5, 10 mM and cowpea was inoculated with Bradyrhizobium yuanmingense strains TSC7, DTC8, and TTC9. The nodulation was strongly inhibited over 7.5 mM N treatment, and only a slight difference was observed between the three strains. However, the application of small amounts (2.5 mM) of nitrogen positively affects the nodulation phenotype (nodule number, nitrogen fixation) at late stage (42 DAT). To assess the effect of Photon flux density on the nodulation phenotype of cowpea associated with nitrogen-fixing rhizobia, 0, 25, 50 and 75 % light intensities were set up. Defoliation was noteworthy in 25 % light intensity at 10 weeks after seedling, and dry weights of pods and seeds were very high compared to the others. No difference was observed in the nodulation phenotype between the three rhizobial strains. Hence, the variation on cowpea growth may arise from the differences between red (R) and far-red (FR) light ratios of treatments. The translocation of carbohydrates might have been accelerated in the 25 % intensity. However, nitrogen concentration of pods and seeds in this treatment was not so different with others. Appropriate shading would therefore, greatly improves cowpea yields, although seed protein content may not vary. .
29. Khin Myat Soe, Takeo Yamakawa, Evaluation of effective Bradyrhizobium strains from Myanmar and co-inoculation with endophytic Streptomyces sp, XV International Congress on Molecular Plant-Microbe Interactions, 2012.07, Soybean (Glycine max L.) is one of the important cash crops in Myanmar. Urea is the main source of nitrogen applied to all crops grown in Myanmar but it is very expensive and not readily available. Rhizobial inoculants can be used to substitute the nitrogenous fertilizers in food legume crops. Indigenous forty-eight root nodules bacteria (MAS1 to MAS48, where MAS means Myanmar Agriculture Service) were collected from different agro-climatic regions of Myanmar in order to evaluate their nitrogen fixing ability for soybean production. After purification, forty-three isolates gave pure colonies and were authenticated for nodule formation on host soybeans in sterilized vermiculite pots in Phytotron (25oC). Based on morphological characteristic, they were identified as Bradyrhizobium strains. These forty-three Bradyrhizobium strains were investigated in symbiosis association with Myanmar recommended soybean, Yezin-6. After inoculation, ten strains were pre-screened based on nitrogen fixation potential determined by using acetylene reduction assay method. When selected ten strains were examined in plant growth and nitrogen fixation with two Myanmar soybeans (Yezin-3 and Yezin-6), MAS23 was found being the most effective strain. The symbiotic relationship between six Bradyrhizobium strains (MAS23, MAS33, MAS34, MAS43, MAS48 and USDA110) and selected endophytic Streptomyces sp. strain (P4) were evaluated with four Myanmar soybean varieties (Yezin-3, Yezin-6, Hinthada and Shan Sein) in pot experiment by using sterilized vermiculite pots in Phytotron (25oC). It was found that dual inoculations of P4 were effectively responded in most of the soybean varieties..
30. Effects of green manure (Sesbania rostrata) on the growth and yield of rice plant and nitrogen fertility in pot experiment.
31. Rice growth, yield and nutrients uptake as affected by the application of rice straw, organic manures and chemical fertilizers as nitrogen sources in paddy field.
32. Effects of phosphite-phosphate interaction on growth and phosphorus supply of hydroponic lettuce (Lactuca sativa L.).
33. Isolation and identification root nodulating bacteria from three cowpea (Vigna unguiculata L. Walp.) cultivars.
34. Isolation and identification root nodulating bacteria from three cowpea (Vigna unguiculata L. Walp.) cultivars.
35. Effects of phosphite, a reduced form of phosphate, on the growth and phosphorus nutrition of spinach (Spinacia oleracea L.).
36. Isolation and identification of cowpea nodulating bacteria from the root nodules of three cowpea (Vigna unguiculata L. Walp.) cultivars.
37. Differences in rice production and nitrogen availability in paddy soils amended with organic manures as nitrogen sources.
38. Search for Rj2-gsn Gene of Bradyrhizobium japonicum Is-1 by Tn5 Mutation. Yousuke Ohtsuka, Hirohito Turumaru, Masao Sakai and Takeo Yamakawa, Japanease Society of Molecular Plant Microbe Interactions, 2006. 9.
39. The examination of the procedure for introducing GFP (green fluorescent protein) gene to dinitrogen-fixing endphyto.  Kazunori Tanaka, Yuu Shimizu, Takeo Yamakawa, Kiwamu Minamizawa, Syouichirou Akao, Society of Japanease Soil Science and Plant Nutrition, 2005.05..
40. Rj-genotype specific nodulation genes for soybean harboring Rj-genes -Cloning of Tn5 insertion flagment in nodulation mutants of B. japonicum strain Is-1 -. Hirohito Turumaru, Takeo Yamakawa, Natuko Kawanami, Yasuharu Ihara, Masao Sakai and Motoki Ikeda, Society of Japanease Soil Science and Plant Nutrition, 2004.09..
41. Agricultural use of banboo material -Soybeen yeild and accumulation of N, P, K under application of bamboo powder-. M. Yamano, M. Ikeda and T. Yamakawa, Society of Japanease Soil Science and Plant Nutrition, 2004.09..
42. Amido synthesis in roots of gramineous and leguminous plants under ammonium application. M. Noguchi, M. Ikeda N. Hashimoto, A. Sugino and T. Yamakawa, Society of Japanease Soil Science and Plant Nutrition, 2004.09..
43. The effect of repening temperature on the isoflvonoids content of soybean seed.O. Nakano, T. Yamakawa, T. Motiduki, S. Tanaka and M. Ikeda, Society of Japanease Soil Science and Plant Nutrition, 2004.09..
44. Cloning and Sequencing of orf1 gene from Bradyrhizobium japonicum Is-1 strain. Natuko Kawanami, Hirohito Turumaru, Takeo Yamakawa, Masao Sakai and Motoki Ikeda, Japanease Society of Molecular Plant Microbe Interactions, 2004.9.
45. The determination of Tn5 insertion site in nodulation mutants of B. japonicum strain Is-1 -. Hirohito Turumaru, Takeo Yamakawa, Natuko Kawanami, Yasuharu Ihara, Masao Sakai and Motoki Ikeda, Society of Japanease Soil Science and Plant Nutrition, 2004.04..
46. The purification of isoflvonoids from soybean seed and the effects of the harvest year on these concentration in seed. O. Nakano, T. Yamakawa, T. Motiduki, S. Tanaka and M. Ikeda, 2004. 4.
47. Relationship between Leaf Senescence and the Contents of Nitrogen and Soluble Protein of Leaves in Soybean. M. Nabeta, S. H. Zheng, T, Yamakawa, M. Iwaya-Inoue, M. Fukuyama, 2004. 3.
48. The genotype-specific nodulation genes for soybean harboring Rj-genes.- Tn5 insertion site in nodulation mutants of B. japonicum strain Is-1 -. Hirohito Turumaru, Takeo Yamakawa, Natuko Kawanami, Yasuharu Ihara, Masao Sakai and Motoki Ikeda, Japanease Society of Molecular Plant Microbe Interactions, 2003.10.
49. Assimilation of ammonium in the roots of wheat and tomato treated with 1,4-cineole. Nami Kawachi, Motoki Ikeda and Takeo Yamakawa, Society of Japanease Soil Science and Plant Nutrition, 2003.09.
50. The characteristics of nitrogen nutrition in soybean cultivar Peking. Syouko Tsukamoto, Takeo Yamakawa and Motoki Ikeda, Japanease society of Soil Science Plant Nutrition, 2003.08.
51. Cloning of the Rj-genotype specific nodulation genes for soybean harboring Rj-genes. Hirohito Turumaru, Takeo Yamakawa, Natuko Kawanami, Masao Sakai and Motoki Ikeda, Japanease society of Soil Science Plant Nutrition, 2003.08.
52. The effects of Co application on the nodulation and nitrogen fixation of soybean. Takeo Yamakawa, Taishi Eiki and Motoki Ikeda, Japanease society of Soil Science Plant Nutrition, 2003.08.
53. The analysis of Rj factor concerned with host specific nodulation. Takeo Yamakawa, Workshop in Sendai, 2003,08.
54. The evaluation of compatibility between bradyrhizobium and Rj-genotype soybean. Comparison between indigenous Bradyrhizobium strain and USDA110, Takeo Yamakawa. Machi Fukuda, Yuuichi Saeki, Masao Sakai and Motoki Ikeda, Japanease society of Soil Science Plant Nutrition, 2003.04.
55. Isolation of the Rj-gene null mutants from Rj2Rj3Rj4-genotype lines. Takeo Yamakawa, Hitomi Fukuda and Motoki Ikeda, Society of Japanease Soil Science and Plant Nutrition, 2002.04.
56. Preference Mechanisms of Rj gene in Soybean for Nodulation by Bradyrhizobium japonicum: Tn5 mutation of Is-1 incompatible with Rj2-soybean and characteristics of mutants. Takeo Yamakawa, Masayuki Tanaka1), Masao Sakai and Motoki Ikeda, 2001.10.
57. The effects of micro elements (Fe, Mo, Co) application on the nodulation and nitrogen fixation of soybean. Taishi Eiki, Takeo Yamakawa and Motoki Ikeda, Japanease society of Soil Science Plant Nutrition, 2001.09.
58. Preference Mechanisms of Rj gene in Soybean for Nodulation by Bradyrhizobium japonicum: Acquisition of and characteristics of nodulation by EMS mutants. Takeo Yamakawa, Masayuki Tanaka, Akino Miyata and Motoki Ikeda, Japanease society of Soil Science Plant Nutrition, 2001.09.
59. Classification of genotyping of Bradyrhizobium strains by AFLP-fingerprinting. Masayuki Tanaka, Takeo Yamakawa, Masao Sakai and Motoki Ikeda, Japanease Society of Molecular Plant Microbe Interactions, 1999.10.
60. Preference Mechanisms of Rj gene in Soybean for Nodulation by Bradyrhizobium japonicum: Isoflavonoid metabolism and nod gene expression. Izumi Kajiwara, Rie Sakamoto, Takeo Yamakawa and Motoki Ikeda, Japanease Society of Molecular Plant Microbe Interactions, 1999.10.
61. The difference between the plant species of micro elements contents in root and root hair. Takeo Yamakawa, Youichiro Kusano, Naoko Okuda and Motoki Ikeda, Japanease society of Soil Science Plant Nutrition, 1998.
62. Preference Mechanisms of Rj gene in Soybean for Nodulation by Bradyrhizobium japonicum: Utilixation of GFP-marked strains. Tatsuyoshi Sumi, Masao Sakai, Takeo Yamakawa and Motoki Ikeda, Japanease Society of Molecular Plant Microbe Interactions, 1998.10.