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Following Japan’s 2011 Fukushima nuclear incident, voluntary participation, rather than mandatory, was adopted as the default scenario for individual radiation monitoring. We evaluated the representativeness of the internal monitoring results from voluntary participants in Minamisoma City, which is located 10–40 km from the Fukushima nuclear plant. Of approximately 70,000 individuals who were residing in Minamisoma City before the incident, a total of 19,263 residents (aged ≥21 years) participated in the monitoring from 1 October 2011 to 31 March 2015. Based on regression projection techniques with the available data obtained from the voluntary participants, the modeled probabilities of radiocesium (Cs) detection in October 2011 for Cs-137 and Cs-134 were 66.9% and 52.9%, respectively, which declined dramatically within a year following the incident. The rate of decline had stagnated since mid-2012, and the probability was close to zero after mid-2014. Sufficient agreement between the modeled probabilities of Cs detection (for the whole population) versus the measured Cs levels (for voluntary participants) was observed, except for Cs-134 in October 2011, indicating that the voluntary monitoring participant group was a good representative sample. Our findings affirmed the clinical importance of voluntary-based monitoring as a screening and dose-assessment tool in a post-nuclear incident. Our study informs societal decision-making regarding the long-term maintenance of the monitoring program under the current low exposure levels.

Following Japan’s 2011 Fukushima nuclear incident, we assessed voluntary-based monitoring behavior in Minamisoma City—located 10–40 km from the Fukushima nuclear plant—to inform future monitoring strategies. The monitoring in Minamisoma included occasional free of charge internal-radiation-exposure measurements. Out of around 70,000 individuals residing in the city before the incident, a total of 45,788 residents (female: 52.1%) aged ≥21 were evaluated. The monitoring prevalence in 2011–2012 was only 30.2%, and this decreased to 17.9% in 2013–2014. Regression analyses were performed to estimate factors associated with the monitoring prevalence and participation behavior. The results show that, in comparison with the age cohort of 21–30 years, the cohort of 71–80 and ≥81 years demonstrated significantly lower monitoring prevalence; female residents had higher monitoring prevalence than male residents; those who were living in evacuation zones at the time of the incident had higher monitoring prevalence than those who lived outside any of the evacuation zones; for those living outside Fukushima and neighboring Prefectures post-incident monitoring prevalence decreased significantly in 2013–2014. Our findings inform the discussion on the concepts of radiation risk perception and accessibility to monitoring and societal decision-making regarding the maintenance of the monitoring program with low monitoring prevalence. We also stress the possibility that the monitoring can work both to check that internal contamination levels are within acceptable limits, and as a risk communication tool, alleviating individuals’ concern and anxiety over radiation contamination.

We employed a multi-tracer approach to investigate sources and pathways of perfluoroalkyl acids (PFAAs) in urban groundwater, based on 53 groundwater samples taken from confined aquifers and unconfined aquifers in Tokyo. While the median concentrations of groundwater PFAAs were several ng/L, the maximum concentrations of perfluorooctane sulfonate (PFOS, 990 ng/L), perfluorooctanoate (PFOA, 1800 ng/L) and perfluorononanoate (PFNA, 620 ng/L) in groundwater were several times higher than those of wastewater and street runoff reported in the literature. PFAAs were more frequently detected than sewage tracers (carbamazepine and crotamiton), presumably owing to the higher persistence of PFAAs, the multiple sources of PFAAs beyond sewage (e.g., surface runoff, point sources) and the formation of PFAAs from their precursors. Use of multiple methods of source apportionment including principal component analysis-multiple linear regression (PCA-MLR) and perfluoroalkyl carboxylic acid ratio analysis highlighted sewage and point sources as the primary sources of PFAAs in the most severely polluted groundwater samples, with street runoff being a minor source (44.6% sewage, 45.7% point sources and 9.7% street runoff, by PCA-MLR). Tritium analysis indicated that, while young groundwater (recharged during or after the 1970s, when PFAAs were already in commercial use) in shallow aquifers (50 m depth) was naturally highly vulnerable to PFAA pollution, PFAAs were also found in old groundwater (recharged before the 1950s, when PFAAs were not in use) in deep aquifers (50-500 m depth). This study demonstrated the utility of multiple uses of tracers (pharmaceuticals and personal care products; PPCPs, tritium) and source apportionment methods in investigating sources and pathways of PFAAs in multiple aquifer systems.

Five years have passed since the accident at the Fukushima Daiichi Nuclear Power Plant. Although the additional exposure doses resulting from the accident were extremely low ([ 1 ][1]), it was difficult to dispel residents' fear of radiation exposure (“Epidemic of fear,” D. Normile, News Feature, 4 March, p. [1022][2]) and other health issues. To address their concerns, we and others have provided a variety of services to increase understanding between residents and medical professionals. We have held more than 500 general health consultations, which connect Fukushima residents with health experts from universities. The experts discuss individual residents' health concerns and symptoms privately and then help coordinate integrated care to promote health and prevent disease. Through these social services, we aim to help dispel apprehensions among the evacuees and residents ([ 2 ][3]). Other local medical professionals and experts have held a series of seminars to open and sustain a dialogue with residents ([ 3 ][4]). The municipality of Date City, which has various levels of contaminated areas, has used feedback about the experiences shared in these seminars to modify their administrative measures and policies and assign staff to explain the personal dosimeter measurement results to individual residents. They also carried out multiple projects to provide mental and physical care for small groups of residents. These activities were implemented based on advice of experts who were by the side of the residents. By putting a liaison in place, medical professionals and experts have transformed a unilateral communication about the risk of radiation into an actively bilateral communication to address the various needs for residents after the accident. Evacuees have been gradually returning to their homes since the designation of evacuation areas was lifted in Fukushima. At this time, they feel anxious about radiation exposure and life in their new environment. Integrated health systems and community dialogues should continue to provide the returning residents with the support they need. 1. [↵][5]1. S. Nagataki 2. et al ., Radiat. Res. 180, 439 (2013). [OpenUrl][6][CrossRef][7][PubMed][8] 2. [↵][9]1. M. Miyazaki , “Yorozu health consultation project,” 4th International Expert Symposium in Fukushima (2015); . 3. [↵][10]International Commission on Radiological Protection, ICRP and Fukushima ICRP Dialogue Initiative ([www.icrp.org/page.asp?id=189][11]). [1]: #ref-1 [2]: /lookup/doi/10.1126/science.351.6277.1022 [3]: #ref-2 [4]: #ref-3 [5]: #xref-ref-1-1 "View reference 1 in text" [6]: {openurl}?query=rft.jtitle%253DRadiat.%2BRes.%26rft.volume%253D180%26rft.spage%253D439%26rft_id%253Dinfo%253Adoi%252F10.1667%252FRR13351.1%26rft_id%253Dinfo%253Apmid%252F24131040%26rft.genre%253Darticle%26rft_val_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Ajournal%26ctx_ver%253DZ39.88-2004%26url_ver%253DZ39.88-2004%26url_ctx_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Actx [7]: /lookup/external-ref?access_num=10.1667/RR13351.1&link_type=DOI [8]: /lookup/external-ref?access_num=24131040&link_type=MED&atom=%2Fsci%2F352%2F6286%2F666.2.atom [9]: #xref-ref-2-1 "View reference 2 in text" [10]: #xref-ref-3-1 "View reference 3 in text" [11]: http://www.icrp.org/page.asp?id=189

Dissolved organic matter (DOM) and phosphate in reclaimed water promote microbial growth in distribution systems and deteriorate water quality. In this study, we tested ferrihydrite (Fh) for its potential to remove both DOM and phosphate in order to control bacterial regrowth. Adsorption kinetics on Fh revealed that phosphate has a higher affinity with Fh than has DOM. The removal efficiency of DOM increased at lower pH. Fourier transform infrared spectroscopy (FT-IR) spectra of freeze-dried Fh showed that adsorbed DOM was rich in carboxyl/hydroxyl functional groups, indicating anion exchange at Fh surfaces to be a major mechanism, especially at low pH. Fh preferentially removed DOM greater than 1,000 Da. Specific ultraviolet absorption (SUVA) at 254 nm and DOC results suggest Fh adsorption removes more hydrophilic DOM than the coagulation–sand filtration process. Reduction of bacterial regrowth potential (BRP) by Fh was comparable to that of the coagulation–sand filtration process, which indicated that phosphorus was not the rate-limiting factor of microbial growth.

While the occurrence of pharmaceuticals and personal care products (PPCPs) in groundwater has typically been reported in bank filtration sites, irrigated fields, septic tanks, and sewage disposal practices, fewer studies have been conducted in highly urbanized areas, where infiltration of treated or untreated sewage is not supposed to be a source of groundwater recharge. Furthermore, little is known about the occurrence of various kinds of PPCPs in relation to microbial indicators in groundwater from different types of aquifers. Thus, we examined the city-wide occurrence of selected PPCPs (diethyltoluamide, crotamiton, ethenzamide, propyphenazone, carbamazepine, and caffeine) and E. coli in 50 groundwaters from unconfined aquifers (

The release of radioactive materials from the Fukushima nuclear power plant after the Great East Japan Earthquake on 11 March 2011 poses health risks. In this study, the intake of iodine 131 (I-131) in drinking water and foods (milk, dairy products, and vegetables) by citizens of Tokyo was estimated. The effects of countermeasures (restrictions on the distribution of foods and the distribution of bottled water for infants) on reducing intake were also evaluated. The average thyroid equivalent doses without countermeasures from 21 March 2011 were 0.42 mSv in adults, 1.49 mSv in children, and 2.08 mSv in infants. Those with countermeasures were 0.28, 0.97, and 1.14 mSv respectively, reductions of 33%, 35%, and 45%. Drinking water contributed more to intake by adults and children than foods. The intake of I-131 within the first 2 weeks was more than 80% of the estimated intake, owing to its short half-life, indicating that rapid countermeasures are important in reducing intake. The average risks of cancer incidence and mortality due to I-131 for infants were estimated to be 3×10(-5) and 0.2×10(-5), respectively, lower than the annual risks of traffic accidents, naturally occurring radioactive material (potassium 40), and environmental pollutants such as diesel exhaust particles.

Iron, cobalt and nickel-4-(2-pyridylazo) resorcinol complexes are extracted into chloroform with counter-cations. The complexes are separated on a column of Waters μ-BONDAPAK tm C 18 with the eluent of methanol-chloroform-water containing phosphate buffer(pH 5.0) (53:2:45, v/v) and are detected at 510 nm. The determination limit is 0.50 ppb of cobalt, and 1.50 ppb of iron and nickel when the ion-pair extraction is applied

Perfluorinated surfactants (PFSs) in wastewater and street runoff in Japan were measured to determine their pathways of travel and utility as indicators of each to water environments. Among PFS species, perfluorooctanesulfonate (PFOS), perfluorooctanoate (PFOA), and perfluorononanoate (PFNA) were dominant in wastewater. PFS concentrations were higher in secondary effluents than in influents, possibly because of biodegradation of their precursors. This was supported by a significant correlation between concentration increases of PFOA and PFNA. Biodegradation of the same precursors probably produced mainly PFOA and secondarily PFNA. Concentrations of perfluorocarboxylates (PFCAs), especially longer- and even-chain PFCAs, in street runoff were equal to or higher than those in wastewater influents and secondary effluents, but PFOS concentrations were lower in street runoff. This result suggests that street runoff potentially contaminates water environments with PFCAs. In street runoff, perfluorodecanoate (PFDA), perfluoroundecanoate (PFUA), and perfluorododecanoate (PFDDA) were abundant along with PFOA and PFNA. PFS profiles in street runoff were significantly different from those in wastewater samples, suggesting that relative proportions of PFSs can be useful as indicators. Four ratios - PFOA/PFOS, PFNA/PFOS, long-chain/(short-chain+long-chain), and even-chain/(even-chain+odd-chain) - were proposed to evaluate the contributions of PFSs from wastewater and street runoff to water environments.

We collected surface sediment samples from 174 locations in India, Indonesia, Malaysia, Thailand, Vietnam, Cambodia, Laos, and the Philippines and analyzed them for polycyclic aromatic hydrocarbons (PAHs) and hopanes. PAHs were widely distributed in the sediments, with comparatively higher concentrations in urban areas (Sigma PAHs: approximately 1000 to approximately 100,000 ng/g-dry) than in rural areas ( approximately 10 to approximately 100g-dry), indicating large sources of PAHs in urban areas. To distinguish petrogenic and pyrogenic sources of PAHs, we calculated the ratios of alkyl PAHs to parent PAHs: methylphenanthrenes to phenanthrene (MP/P), methylpyrenes+methylfluoranthenes to pyrene+fluoranthene (MPy/Py), and methylchrysenes+methylbenz[a]anthracenes to chrysene+benz[a]anthracene (MC/C). Analysis of source materials (crude oil, automobile exhaust, and coal and wood combustion products) gave thresholds of MP/P=0.4, MPy/Py=0.5, and MC/C=1.0 for exclusive combustion origin. All the combustion product samples had the ratios of alkyl PAHs to parent PAHs below these threshold values. Contributions of petrogenic and pyrogenic sources to the sedimentary PAHs were uneven among the homologs: the phenanthrene series had a greater petrogenic contribution, whereas the chrysene series had a greater pyrogenic contribution. All the Indian sediments showed a strong pyrogenic signature with MP/P approximately 0.5, MPy/Py approximately 0.1, and MC/C approximately 0.2, together with depletion of hopanes indicating intensive inputs of combustion products of coal and/or wood, probably due to the heavy dependence on these fuels as sources of energy. In contrast, sedimentary PAHs from all other tropical Asian cities were abundant in alkylated PAHs with MP/P approximately 1-4, MPy/Py approximately 0.3-1, and MC/C approximately 0.2-1.0, suggesting a ubiquitous input of petrogenic PAHs. Petrogenic contributions to PAH homologs varied among the countries: largest in Malaysia whereas inferior in Laos. The higher abundance of alkylated PAHs together with constant hopane profiles suggests widespread inputs of automobile-derived petrogenic PAHs to Asian waters.

Groundwater replenishment by infiltration of road runoff is expected to be a promising option for ensuring a sustainable urban water cycle. In this study, we performed a soil infiltration column test using artificial road runoff equivalent to approximately 11-12 years of rainfall to evaluate the removal of pollutants by using various chemical analyses and bioassay tests. These results indicated that soil infiltration treatment works effectively to remove most of the pollutants such as organic matter (chemical oxygen demand (CODMn) and dissolved organic carbon (DOC)), P species, polycyclic aromatic hydrocarbons (PAHs), numerous heavy metals and oestrogenic activities. Bioassay tests, including algal growth inhibition test, Microtox and mutagen formation potential (MFP) test, also revealed effective removal of toxicities by the soils. However, limited amounts of NO3, Mn, Ni, alkaline earth metals, perfluorooctane sulphonate (PFOS) and perfluorooctane sulphonamide (FOSA) were removed by the soils and they possibly reach the groundwater and cause contamination.

We collected samples of roadside air, automobile exhaust soot, tires, asphalt, and used engine oil in a tropical Asian mega-city, Bangkok, Thailand, and analyzed them for polycyclic aromatic hydrocarbons (PAHs) and hopanes. The concentrations and compositions of PAHs and hopanes were utilized to identify the sources of PAHs in street dust, in which high concentrations of PAHs were reported in our previous study. Weight-based concentrations of total PAHs had the following order: gasoline-powered vehicle soot (2600+/-2900 microg/g; n=4)diesel-powered vehicle soot (115+/-245 microg/g; n=7) approximately roadside aerosols (101+/-35 microg/g; n=5) approximately used engine oil (97+/-65 microg/g; n=4) approximately tire wear particles (82+/-41 microg/g; n=5)asphalt (2.3+/-1.6 microg/g; n=3)street dust (1.1+/-0.8 microg/g; n=10). In cluster analysis, all the source materials fell into different clusters from that in which street dust fell, indicating that multiple source materials contribute to PAHs in the street dust. Multiple regression analysis of PAH profiles and diagnostics of hopane compositions identified tire debris as the major contributor of PAHs to street dust, followed by diesel vehicle exhaust.

Individual particles containing Cr and/or Pb and other major components were identified in road dust from a heavily used road (hereinafter ‘heavy traffic road dust’), road dust from a residential area and soakaway sediment by electron probe microanalyser to locate their sources and carrier particles. Individual particles containing high levels of Cr and/or Pb (⩾0.2%) were identified using wavelength dispersive spectrometry (WDS) map analysis. Chromium, Pb and other major elements were then determined by means of a combination of WDS and energy-dispersive spectrometry in all identified particles, 50 particles containing neither Cr nor Pb from each type of road dust and soakaway sediment, and yellow road line markings. WDS map analysis revealed that many particles containing both Cr and Pb were present among the identified particles in heavy traffic road dust, whereas they were minor components in road dust from the residential area and soakaway sediment. The plots of X-ray intensities of Cr vs. Pb were linear for the identified particles containing both Cr and Pb in heavy traffic road dust, and the line closely fitted the plots for the three yellow road line marking samples. Individual particles were then classified using cluster analysis of element components. The results revealed that the adsorption of source materials or released metals onto soil minerals occurred in road dust and soakaway sediment, that the yellow road line markings were sources of Cr and Pb in heavy traffic road dust, and that materials containing Fe as a major component, such as stainless steel, were additional sources of Cr in both road dust and soakaway sediment.

Although there have been simulation researches focusing on reduction of stormwater peak flow by introduced infiltration facilities, model simulation of dynamic runoff behavior is still limited for frequently occurring rainfall events with weak intensity. Therefore, dynamic simulation was carried out in two urban drainages with infiltration facilities incorporated with a distributed model using two methods for describing functions of infiltration facilities. A method adjusting effective rainfall model gave poor simulation of runoff behavior in light rainfalls. Another method considering dynamic change of storage capacity as well as infiltration rate gave satisfactory estimation of the runoff in both drainages. In addition, assumption of facility clogging improved the agreement between measured and simulated hydrographs in small and medium-sized rainfall. Therefore, the proposed method might be useful for quantifying the secondary effects of the infiltration facilities on groundwater recharge and urban non-point pollutant trapping as well as runoff reduction. © IWA Publishing 2005.

Polycyclic aromatic hydrocarbons (PAHs) present in size- and density-fractionated road dust were measured to identify the important fractions in urban runoff and to analyse their sources. Road dust was collected from a residential area (Shakujii) and a heavy traffic area (Hongo Street). The sampling of road dust from the residential area was conducted twice in different seasons (autumn and winter). The collected road dust was separated into three or four size-fractions and further fractionated into light (1.7 g/cm3) and heavy (1.7 g/cm3) fractions by using cesium chloride solution. Light particles constituted only 4.0+/-1.4%, 0.69+/-0.03% and 3.4+/-1.0% of the road dust by weight for Shakujii (November), Shakujii (February) and Hongo Street, respectively but contained 28+/-10%, 33+/-3% and 44+/-8% of the total PAHs, respectively. The PAH contents in the light fractions were 1-2 orders of magnitude higher than those in the heavy fractions. In the light fractions, the 12PAH contents in February were significantly higher than the 12PAH contents in November (P0.01), whereas in the heavy fractions, no significant difference was found (P0.05). Cluster analysis revealed that there was a significant difference in the PAH profiles between locations rather than between size-fractions, density-fractions and sampling times. Multiple regression analysis indicated that asphalt/pavement was the major source of Shakujii road dust, and that tyre and diesel vehicle exhaust were the major sources of finer and coarser fractions collected from Hongo Street road dust, respectively.

Road and roof dust was collected and samples of runoff were taken at an urban storm sewer system in a residential area in Japan. Suspended solids (SS) in the runoff samples were classified into two fractions: fine (smaller than 45 microm) and coarse (larger than 45 microm). Runoff monitoring and chemical analysis data were also used to validate a runoff model for particle-bound polycyclic aromatic hydrocarbons (PAHs) that was originally developed to explain the behaviour of SS in the same area. The model, in which roads and roofs were considered separately as impervious surfaces, expressed the SS and particle-bound PAHs runoff behaviour for fine and coarse particles very well, except during and after heavy rainfalls (more than 10mm/h). However, the model could not explain the PAH profiles of runoff particles; the profiles of 12 PAH compounds tracked in this study were almost constant and more similar to those of road dust than roof dust throughout the event. An improved model is developed which explains the runoff behaviour by considering two types of road dust with different mobility.

Eighty-five coronary artery patients examined using an ambulatory electrocardiogram-respiration monitoring system (AERMS) in which a respiratory sensor was strapped to the right upper abdominal wall. Apnea was defined as a cessation of abdominal wall movement lasting at least 10 sec. Sleep-related breathing disorder (SRBD) was diagnosed if at least 30 apneic episodes were observed during sleep. The cardiac events evaluated during follow-up included occurrence of sudden death, myocardial infarction and ventricular tachycardia. SRBD was detected in 9 of 85 patients (11%). There were more patients with low EF (EF < 50%) in the SRBD group than in the non-SRBD group (p < 0.01). During follow-up for a mean period of 18.4 +/- 7.6 months after ambulatory recording, four of nine (44%) patients in the SRBD group had cardiac events, compared with only four of 79 (6%) patients in the non-SRBD group (p < 0.001). Thus, coronary artery patients who were complicated with SRBD showed poor cardiac function and had a high incidence of cardiac events.

Environmental contextAs perfluorocarboxylates can be carried by surface runoff to waters and cause adverse effects to aquatic organisms, we evaluated the contributions of wastewater and surface runoff to the concentrations of these compounds in Tokyo Bay during dry and wet weather. Sewage markers revealed that the surface runoff was a significant source of perfluorocarboxylates in the bay during wet weather. This finding leads to a greater understanding of sources and pathways of perfluorocarboxylates in waters. AbstractWe investigated the occurrence of perfluorocarboxylates (PFCAs) in Tokyo Bay during dry and wet weather and evaluated the contributions of wastewater effluent, untreated wastewater, and surface runoff by using two sewage markers, caffeine and crotamiton. ∑8PFCAs ranged from 11 to 185 ng L–1. Perfluorononanoate (PFNA) was the major species, followed by perfluorooctanoate (PFOA) and perfluoroheptanoate (PFHpA). Principal component analysis followed by multiple linear regression revealed that the PFCAs were derived mainly from wastewater effluent during dry weather, and jointly from wastewater effluent (59%) and combined sewer overflow (41%) during wet weather. We used caffeine-to-crotamiton ratios to evaluate the contributions of untreated wastewater and wastewater effluent. Estimated concentrations of wastewater-derived PFCAs were much lower than observed concentrations during wet weather, indicating the contribution of surface runoff to contamination. During a combined sewer overflow, surface runoff had a significant effect on contamination in the bay.

水稲の生産性におよぼすタイヌビエの影響をみるために, タイヌビエの発生時期や生育期間を人為的に変化させて検討した。すなわち, 熟期の異なる水稲2品種の種々の生育時期にタイヌビエを混植あるいは除草することによって, タイヌビエとの競争による水稲の減収要因を生長解析によって分析した。その結果, いずれの競争区においても水稲の収量は単植区よりも減少し, 両植物の競争期間が長いほど, また, この競争が生起する生育時期が早いほど減収率は大きかった。この収量減を収量構成要素の面よりみれば, 1穂重の減少によるよりも, むしろ穂数減に起因するところが大きく, さらに, 水稲の乾物生産性の面から分析すれば, 生育初期におけるNARと出穂期以後におけるCGRの低下によるものと推察された。一方, 水稲品種の早晩性よりみた場合, タイヌビエの影響は晩生品種におけるよりも早生品種においてかなり大きくあらわれた。, The influence of the weed barnyardgrass (Echinochloa crusgalli BEAUV. var. oryzicola OHWI) on the productivity of paddy rice was investigated in relation to emergence time and growing period of the weed. Twelve day-old weed seedlings were transplanted 10,30 and 50 days after transplanting of the two rice varieties which differ in maturity date. The weeds which had been transplanted 10 days after transplanting the rice were hand-weeded at various times. The factors causing reduction in rice yield due to competition with the weed were examined by growth analyses. In all the competition plots rice yield was smaller than in the single cropping plot and, in general, the longer was the competition period of the two plants and the earlier the beginning of the competition, the larger was the yield reduction rate of rice. These reductions of rice yield were caused largely by the decrease in the number of panicles rather than in the panicle weight, and it was infered further that the reductions were attributable to the decrease in net assimilation rate in the early growing stage and in crop growth rate after heading. It was also recognized the influence of the barnyardgrass on the rice productivity was larger in the early-maturing variety than in the late-maturing one.

大豆の2品種, シンメジロとタチスズナリの種子とカルスを用い, 放射線感受性について比較した。カルスの生育に対する放射線の影響は, 線量の増加に伴って増大し, シンメジロでは7.5KR以下では生育したが, 10KRではわずかに生育するにとどまり, 20KRではほとんど生育が認められず, 一方, タチスズナリでは20KRまでは生育したが, 30KRではほとんど生育が認められなかった。カルスの生体重および乾物重に関するRD_は, タチスズナリがシンメジロの約2倍であった。照射カルスの継代能力はシンメジロでは10KR以下で, タチスズナリでは30KRでもわずかに認められた。種子照射における生育抑制はシンメジロでは15KR, タチスズナリでは40KR以上で顕著であった。RD_はタチスズナリがシンメジロの約2倍を示した。以上の結果から, 両品種の放射線感受性の差異はカルスと種子とでは同程度であり, かつ, カルスは種子よりも感受性であることが判明した。, Effects of ^Co gamma radiation on hypocotyloriginated callus tissues and seeds of two soybean varieties, Glycine max (L.) Merr. vars. Shinmejiro and Tachisuzunari, were compared. Callus growth of Shinmejiro and Tachisuzunari was nearly equal as compared to the control at a dose of 2.5KR and below 5KR, and decreased with increasing doses from 5 to 10KR and from 10 to 20KR, and ceased practically at 20KR and at 30KR, respectively. From comparisons of RD_ on the fresh and dry weight between two varieties, Tachisuzunari was about twice as resistant as Shinmejiro. The potency of growth in subcultures for 30 days of irradiated- and 30-day-cultured callus was recognized below 10KR in Shinmejiro, and slightly at a dose of 30KR in Tachisuzunari. Severe inhibition of growth of irradiated seeds occured at and above 15KR in Shinmejiro and at and above 40KR in Tachisuzunari. From comparisons of RD_ on fresh and dry weight and seedling height of irradiated seeds, Tachisuzunari was about twice resistant as Shinmejiro. Varietal differences in the radiosensitivity nearly equalled in irradiated seeds and in callus tissues. A striking difference in the radiosensitivity between seeds and callus tissues, was observed, however, callus tissues beeing sensitive than the seeds.

作物の1個体内の相同器官に生起する変動性に関しては, 従来より選抜対象としてはほとんど考慮されていないが, この個体内の変動性が諸形質の形質発現力の変化に伴ってどのように変化してきたかを調べるために, 現在のわが国の水稲主要品種のうちより6品種と, それらの祖先にあたる28品種を供試して, 品種の変遷に伴う個体内変動性の推移を検討した。一般に, 諸形質の形質発現力は品種の変遷に伴って減少し, 現在の主要品種はかなり短稈で穂が小さく, いわゆる短稈, 多けつ型品種となってきているが, 個体内の変動性は, これとは逆に品種変遷が進むに従って増大する傾向を示している。すなわち, 諸形質の発現力とその個体内変動性は, 逆の関連性をもって品種変遷をたどってきた傾向にあることが推察された。, From the point of view that the variability which occures among culms or panicles contained within a plant (Within CV) must have had changed in some connection with the change of character manifestation (character value), although it had not been treated as an object of selection, the changes in the variabilities of several characters in rice were investigated. Six recent leading varieties and their twenty-eight ancestral varieties were cultured in 1976. In general, Within CV of all the characters examined increased according as the genealogies proceeded from the varieties which had been bred in old times to recent varieties, whereas character values decreased. Namely, character manifestations and the variabilities occuring within a plant had changed to the reverse direction to each other and the recent varieties showed the shorter culms, smaller panicles and lager variabilities occuring within a plant than those of mean values of all the varieties tested.

丹波黒大豆(京都1号)の気乾種子を用い, 5&acd;40KRの^(Co)γ線を照射して, 放射線感受性を検討した。幼苗長は10KRまでは対照区とほとんど差異は認められなかったが, 20KR以上では線量の増加に伴って有意に減少した。これは主として子葉から初生葉までの子葉節長の障害に起因しているものと思われる。開花始は20KRまでは対照区に比べてやや遅延し, 30KR以上では, 2,3日の有意な遅延が認められ, かつ, 分散も大となった。成熟期における諸形質は, 100粒重をのぞいて, 概して線量の増加に伴って減少を示したが, その様相には形質によって差異が認められ, 莢数, 莢重, 粒数および粒重において障害が著しかった。以上の結果から, 丹波黒大豆の放射線感受性は大豆のうちでは概して「中&acd;やや強」であるものと推察された。, Dry seeds of a black soybean, Glycine max (L.) Merr. cv. Tanba-Kuro, with about 11% moisture were given acute gamma radiation exposures of 5,10,15,20,30 and 40KR from a 1,800 Ci ^(Co) source. Seedling height was nearly equal to the control at 10KR and below, while at 20KR and over decreased significantly with increasing doses. We supposed that this decrease resulted from the damage of epicotyl (length between cotyledon and primary leaf). The day of the first flower in individual plants was slightly later than the control at 20KR and below, and was significantly delayed by 2 to 3 days at 30KR and over. Moreover, its variance was larger than the control with increasing doses. Values of some characters in maturing time, in general, was decreased with increasing doses as compared to the control. While the patterns of reduction showed striking differences in some characters, the reduction was severe in the number of pods, pods weight, number of seeds and seeds weight. We assumed that the radiosensitivity of "Tanba-Kuro" held the "middle to semi-resistant" position in soybean.

作物の適応性あるいは収量安定性と諸形質の発現力の変動性との関係を栽培環境条件の変化と関連して考察するために, 水稲12品種を供試して, 密度変化に伴う諸形質の個体内変動量(内CV)と個体間変動量(間CV)の変異について検討した。1) 諸形質の変動性程度は形質の種類によって異なり, 稔性は内, 間両CVともに最も低く, 粒数と収量はかなり高い値を示す。2) 個体内変動と個体間変動とでは, いずれの形質においても内変動の方が大きく, 稔性を除いては, 2倍以上の差異を示している。3) 間CVの分散分析における密度要因は全形質ともに有意であり, 一般に密度変化が変動性に及ぼす影響は, 個体内よりも個体間において強く現われることが認められる。4) 供試品種の栽培地の地域性と個体内変動量との間にはかなり高い関連性が認められ, さらに内CVの分散分析における品種要因はいずれの形質においても有意であり, 個体内の変動性には高い遺伝力が存在するものと思われる。, The present paper is the first report of a series of investigation on the relationship between yield stability and variabilities of character manifestaion in connection with differences in environmental conditions. The 12 rice varieties were cultured under three density levels, and the effect of density on the variations which occurred within a plant (Within CV) and between plants (Between CV), was examined. The results are summarized as follows : 1) The degree of variability varied to some extent by the difference in the sort of character. Among all the characters investigated, fertility showed the lowest values in both Within CV and Between CV. Number of kernels and panicle weight, on the other hand, showed high values. 2) The values of Within CV of all the characters except in fertility, amounted more than twice that of Between CV 3) As the result of analysis of variance on Between CV, the density effects were significant in all the characters, and it was recognized that the difference in density influenced more strongly the variability in between plants than that in within a plant. 4) The close relationship was recognized between the locations where those varieties are ordinarily cultured and variation in within a plant. The variety effects were significant in all the characters in the analysis of variance on Within CV, so that it is suggested that there is high heritability on the variability in within a plant.

水稲における穂の形態的変異を調べるために, 穂型に関与する20形質の品種間変異を考察するとともに, それらの個体内穂間変異についても検討した。穂軸長の品種間変異の程度に比べて, 1穂当りの着粒数のそれはかなり大きかった。この着粒数の品種間差に最大の影響を及ぼす要因は2次枝梗数であり, 供試各品種の2次枝梗数の大小順位と1穂着粒数のそれとは一致した。1次枝梗数がこれに次いで大きく影響するものと考えられた。しかし, 1次, 2次枝梗とも1枝梗当りの長さの品種間変異は概して小さかった。また, 着粒密度と1枝梗当りの着粒数の品種間差も一般に小さかったが, 2次枝梗の着粒密度が1次枝梗のそれに比べて顕著に大きいことが注目された。一方, 諸形質の個体内穂間変異の程度はいずれの品種においても概して等しい値を示したが, 形質の種類による差は大きく, 一般に2次枝梗が関与する形質において大きい変異を示した。また, 個体内変異の程度が大きい形質ほど形質値の品種間変動が大きくなる傾向が認められた。, In order to investigate morphological variations of rice panicle, varietal variations among six varieties and intra-plant variations among panicles within a plant were examined for twenty characters concerned in panicle shape. The degree of varietal variation in number of spikelets per panicle was considerably larger than that of rachis length. This varietal variation in number of spikelets per panicle was contributed largely by the difference in number of secondary rachis-branches per panicle. The varietal variations for average lengths of primary and secondary rachis-branches were fairly small, and the variations for numbers of spikelets per primary and secondary rachis-branches and spikelets setting densities on the both branches were also small. Spikelets setting density on secondary rachis-branches was about three times larger than the density on primary rachis-branches. The varietal variations for the intra-plant variations were considerably small in many characters. However, the degrees of intra-plant variations varied largely due to the differences in characters and the intraplant variations of characters concerned in secondary rachis-branches were generally larger than the variations of characters concerned in primary ones.

筆者らは, 最近とくに減少しつつある作物の遺伝子源を保存し, その特性を再検討するという見地より, 各種の特用作物について, 在来系統の分布とその類縁性の解析, ならびに系統発生的分化に関する研究を実施中である。本法は, そのうち, 各地域より収集したシソの在来系統に対して主成分分析法を適用し, 系統の群別化と系統群相互の類縁関係を検討し, あわせて主成分のもつ生物学的意義について考察したものである。わが国および韓国より収集した39の在来系統に対し, シソ全体, 青シソおよび赤シソに区分した場合, 各々に対する主成分分析の国有値(λ_k)は, 第3成分までで全分散のそれぞれ74.4%, 84.8%および76.7%が表わされる。従って第3成分までの成分スコアによって系統の分類を行なった結果, シソ全体では10群, 青シソは11群, 赤シソは6群に分類される。この分類結果は, 本法と同様に距離に判定基準をおく場合のクラスター分析の結果とよく一致しているので, 主成分分析法はシソの系統分類の手法としてかなり有効であるものと推察される。青シソ, 赤シソとも, 同一群に所属する系統はシソ全体においてもほぼ同じ群に分類され, 質的形質である葉色発現機構の差異は, 量的形質に基づく分類結果に対して殆んど影響を及ぼさないものと考えられる。各主成分に関する生物学的意義を検討した結果, 一般にシソの特性決定には, 早晩性, 葉のちりめん状態, 粒重および分枝穂の形状が大きい支配力を有するものと推察される。, The 39 local lines of "Shiso" (Perilla frutescens Britton var. crispa Decne.) collected from Japan (38 lines) and R. O. K. (1 line) were classified by application of the principal component analysis (P. C. A.) in order to investigate the phylogenetic differenciation and to conserve desirable gene sources of the crop. Twenty nine characters were investigated, from which the representative characters were selected based on correlation matrix of characters showing significant line differences, and only these characters were analysed thereafter. Lines were divided by leaf colour to 29 green lines (Aoshiso) and 10 red lines (Akashiso). "Shiso" (Aoshiso+Akashiso), Aoshiso and Akashiso were analysed by P. C. A. separately, and the cumulative contributions of eigen values to the first three pricipal components amounted to 74.4%, 84.8% and 76.7%, respectively. Classification of lines by use of component scores of the first three components, as more than 70% cumulative contribution is enough to analyse, resulted in 10,11 and 6 groups in "Shiso", Aoshiso and Akashiso, respectively. The P. C. A. was considered an efficient procedure to classify the crop, because of coincidence of this classification result with the cluster analysis based on mean distances among characters. The lines belonging to the same groups in Aoshiso and Akashiso classifications were almost always assorted to the same groups in "Shiso" classification. Therefore, the difference in leaf colour manifestation as a qualitative character was considered unrelated to classification due to quantitative characters. Judging from the contributions of eigen vectors to the first three components, each component was interpreted to possess the biologlogical significance as follows : 1) First component : concerned with growing period, seed ripening and leaf shape. 2) Second component : concerned with growing period and luxuriance of plant. 3) Third component : concerned with shape of maximum branch. From the result mentioned above, the P. C. A. is contemplated to give promissing clues to the concideration of phylogenetic differenciation and to search and selection of breeding materials in "Shiso".

稈長の1個体内における変異を各節間長の個体内変異に分解して検討するために, 水稲11品種を供試し, 各品種20個体について全分けつの上位4節間長と第5節間以下の総節間長を調査し, 各節間長の個体内変異が稈長のそれに及ぼす効果を分析した。稈長の個体内変異はいずれの節間長におけるよりも大きく, また各節間の間では第1節間長の変異が最大となり, 第2,第3節間長の変異は概して小さかった。一方, この個体内変異を各々の長さとの割合でみた場合には, 下位節間長の変異がかなり大きい値を示した。稈長と各節間長との個体内相関はいずれの場合にも正の値を示し, 各節間が長くなる程長稈になる傾向を示したが, この関連性は第2節間において最小であった。稈長の個体内変異に対する各節間長の個体内変異の寄与率は, 品種によってかなり異なるパターンを示したが, 一般に第1節間における寄与が最大で, 第2節間の寄与はきわめて小さかった。, The relationship between the intra-plant variation of culm lengths, and the intra-plant variations of the five internodes lengths in 11 paddy rice varieties was investigated. Twenty mature plants in each variety were sampled, and the upper four internodes lengths and the total length of remainig internodes of all the culms contained within a plant were examined. The intra-plant variation of the first internode lengths was largest of the five internodes lengths variations, whereas the variations of the second and the third internodes lengths were small. All the intra-plant correlation coefficients between culm length and the internodes lengths were positive. The relationship was smallest in the second internode length. The patterns of contribution rates due to the intra-plant variations of the five internodes lengths, to that of culm lengths varied with different varieties. In general, the contribution rate due to the first internode length was largest, whereas that due to the second internode length was very small.

栽培環境の変化に伴うNew Coix系統の形質発現の変異と形質間の相関の変動を検討するために, 供試系統を湛水田および畑で栽培し, 標準施肥の3倍量の多肥を与えて形質発現を解析した。水田, 畑両区における形質発現力の差異は, 形質の種類によって異なり, 草丈, 葉面積は施肥量に関係なく畑区がすぐれ, 分げつ数は逆に水田区で増加した。また多肥の効果は概して畑区で強く現われた。一般に環境変化による影響のうけやすい形質の発現力は大きい変動性を示した。水田区の形質発現力は畑区のそれに比べてやや劣るが, なおかなりの生産力を維持しており本系統の耐湿性はかなり強い。New Coix系統間の形質変動性は, 水田区では多肥により増大する形質が多いが, 畑区では逆に減少の傾向が認められた。全試験区を通じて, 草丈, 稈径, 葉厚, 葉面積および花粉稔性の変動性は小さく, 形質発現に安定性が認められる。草丈に対する茎葉諸形質の表現型相関は, 分げつ数を除きいずれの試験区においても高い有意相関を示しており, 遺伝相関はすべて表現型相関を上まわり概して環境相関は低い。草丈と分げつ数との間には, 雑種初期世代で認められたような負の相関は認められない。一般に, New Coix系統の高稈性と多収性にはかなり強い遺伝的関連性があることが推察された。, The primary objective of the present study is to analyze the variations of character manifestation and correlation between characters in improved strains of the genus Coix (New Coix strains) cultured in various environmental conditions of field. Six New Coix strains and their parental strains were grown in submerged and upland fields fertilized three times normal amount of manure. The results are summarized as follows : 1) The differences in character manifestation between submerged and upland fields varied with characters. Irrespective of amount of manure, plant height and leaf area in upland field were superior to those in submerged field, and in case of number of tillers the tendency was reversed. Heavy manuring was more effective for character manifestations in general in upland field than in submerged field. Generally, characters which were fluctuable by change of environments varied largely. As the New Coix strains showed fairly high productivities in submerged field in spite of the somewhat inferior character manifestations as compared to those in upland field, the wet endurances of these strains were recognized considerably strong. 2) Variations in many characters due to the differences in strains were increased by heavy manure in submerged field, but they showed a reverse tendency in upland field. The character manifestations of plant height, culm diameter, leaf thickness, leaf area and pollen fertility were considered fairy stable. 3) Significantly high phenotypic correlations were estimated between plant height and some vegitative characters and all the genetic correlations were still higher than those phenotypic correlations, but environmental correlations were generally low. Negative correlation which had been estimated in the early hybrid generations was not recognized between plant height and number of tillers.

最近とくに減少傾向の著しい作物の遺伝子源を確保・保有して, その特性の再検討を行うという見地より, 各種の特用作物についてその在来系統の分布と類縁性の解析ならびに系統発生的分化に関する研究を行っている。本報はエゴマについての分類結果である。即ち, 各地より収集したエゴマの在来系統に対して, 主成分分析法を適用して系統の群別化と系統群相互間の類縁関係を検討し, あわせて主成分のもつ生物学的意義について考察したものである。日本, 韓国, アメリカ, ソ連, インドおよびデンマークなどより収集した111のエゴマ在来系統に対して主成分分析の固有値(λ_k)を求めると, 第5成分までで全分散の約79%が表わされた。従って, 第5成分までの成分スコアを用いて系統の分類を行った結果, 13群に分類されることが判明した。これらの群には1系統1群のものから35系統1群のものまでかなり変異することが認められた。この分類結果はクラスター分析の結果とかなり一致している。また, 各主成分に関する生物学的意義を検討した結果, 一般にエゴマの特性決定には早晩性, 草丈, 含油量および脂肪酸などが大きい支配力を有するものと推察される。, The 111 local varieties of perilla (Perilla ocimoides L.) collected from Japan (74 lines), R.O.K. (24 lines), U.S.A. (8 lines), India (3 lines) U.S.S.R. (1 line) and Denmark (1 line) were classified by application of the principal component analysis (P. C. A.) in order to investigate the phylogenetic differenciation and to conserve desirable gene sources of the crop. Twenty eight characters were investigated, from which eight representative characters were selected based on correlation matrix of characters showing significant line differences, and the selected characters were analysed thereafter. The cumulative contributions of eigen values to the first five principal components amounted to 22.4%, 17.2%, 14.6%, 13.4%, 11.6% respectively. Classification of lines by use of component scores of the first five components resulted in 13 groups. The classified group by P. C. A. approximately coinside with grouping results by the cluster analysis. Judging from the contribution of eigen vectors to the first five components, each component was interpreted to possess the biological significance as follows : 1) First component : concerned with growing period and plant type. 2) Second component : concerned with oil content and fatty acid (linolenic acid). 3) Third&acd;Fifth component : concernde with seed yield. From the results mentioned above. the principal component analysis is contemplated to give available clues to the conciderration of phylogenetic differentiation in perilla.

菜豆(Phaseolus vulgaris L. cv. Kentucky Wonder)のカルス, 幼苗および種子に対するγ線照射の影響を比較した。照射カルスの生長は線量の増加に伴って有意な減少を示したが抑制程度は一様ではなく, 初期から生長が認められた2.5&acd;5KR, 生長遅延を示したが生長を続けた6.25&acd;8.75KRおよびほとんど生長が認められなかった10KR以上のほぼ3群に大別された。照射カルスの継代能力は12.5KR以上ではほとんど認められなかった。カルスは線量の増加に伴って褐色の度合およびもろさの程度が増加した。一方, 幼苗照射における生長抑制は, 1KRでは約50%で頂端分裂組織も正常であったが, 2KRでは顕著な抑制と頂端分裂組織の脱落が認められ, 5KR以上では枯死した。また, 種子照射においては, 10KRまでは約30%の抑制であったが, 20KR以上ではほとんど生長が認められなかった。以上の結果から, 生長抑制でみた菜豆のカルス, 幼苗および種子の放射線感受性には顕著な差異が認められた。すなわち, 幼苗が最も感受性で, 種子が抵抗性であり, カルスはほぼその中間であった。, A comparative study on the effects of ^(Co) gamma radiation was carried out on callus tissue, seedlings and seeds of Phaseolus vulgaris L. cv. Kentucky Wonder. Callus was obtained from the hypocotyl pieces grown on an agar-solidified, modified Linsmaier and Skoog's medium supplemented with 2,4-D (5mg/1), kinetin (5mg/1) and yeast extract (1,000mg/1). Subculture was conducted on the same medium in the dark at 28±1℃. Callus was exposed to various doses (2.5-15KR) of gamma radiation at 20KR/hr. Fresh and dry weight, potency of growth in subculture of irradiated callus, color and friability were measured. As compared with control, irradiated callus growth showed a significant decrease with increasing doses. Callus growth was classified into three types, i.e. callus began to grow from the early stage of culture at 5KR and below, from 6.25-8.75KR there was a delayed growth, at 10KR and over there was little visual sign of growth. The potency of growth in subculture for 28 days of irradiated- and 24-day-cultured callus was recognized at 10KR and below. With increasing doses, color of callus darkened, and the degree of friability increased. While 10-day-old seedlings were irradiated, striking inhibition of growth occurred at 2KR, followed by degradation of the apical meristem and growth ceased completely at 5KR. Severe inhibition of growth of irradiated seeds occurred at 20KR and over. A remarkable difference in radiosensitivity was observed among callus tissue, seedlings and seeds, i.e. seedlings were most sensitive, followed by callus tissue, and seeds were most resistant.

ハトムギ, ジュズダマおよびその雑種F_1ならびに4xF_1の4植物の耐水性の差異を検討するために湛水試験を行なつた。草丈は各植物とも湛水1週間後に生育抑制があらわれるが, ジュズダマ, F_1および4xF_1の3植物は, 生育後期に急速に回復し, 伸長停止期には標準区に比べかなりすぐれた。また分蘗数および葉数の増加に対する湛水の影響も植物種類により差異がみられ, ジュズダマは湛水により生育促進の傾向を示し, F_1もほぼこれに近く, 4xF_1では分蘗数に対する抑制が認められた。これに反しハトムギは両形質とも湛水の初期より著しく生育抑制がみられ, 生育後期ほどその影響は顯著であつた。成熟期における茎葉諸形質の測定の結果, 草丈, 分蘗数, 葉数および葉長などの形質は, 葉巾, 葉厚および稈径などに比べ, 植物の耐水性の差によつて湛水による増減が著しい。各植物とも花粉稔性には湛水による差異はみられないが, 種子稔性は湛水によりやや向上した。湛水により根長の発育は著しく抑制されたが, 多数の細根の発生によつて根重は各植物とも増加した。本実験の結果より耐水性に関しては, ジュズダマおよびF_1は極めて強く, 4xF_1はこれらに次ぎ, ハトムギは最も弱いことが判明した。, The present paper deals with the results of investigations on the submersion resistance of four Coix varieties, namely Hatomugi (Coix Mayuen ROMAN.), Juzudama (C. Lacryma-Jobi L.), F_1 (Hatomugi×Juzudama) and 4xF_1 plants. These Coix plants were planted in wagner's pot and submerged. Throughtout these four Coix varieties, the growth of plant height, number of tillering and number of leaves were inhibited in about 1 week after submersion. But the recuperation of these growth in Juzudama and F_1 and of plant height in 4xF_1 were recognized remarkably in 5&acd;7 weeks after submersion. In the date of maturity, these characters of Juzudama, F_1,and 4xF_1 planted in submerged plot were superior than the control. The seed fertility and dry matter of roots in the submerged plants were increased. From these results mentioned above, it will be identified that the submersion resistance of Juzudama, F_1 and 4xF_1 are superior than Hatomugi.

わが国各地に分布するCoix属植物は, 栽培種のハトムギと, 野生種のジュズダマの2種を主体とし, オニジュズダマの分布は少ない。したがって, ハトムギおよびジュズダマのわが国における生態型を把握するために, 地理的分布にともなう主要形質の変異について考察した。すなわち, 全国各地から収集したハトムギ16系統と, ジュズダマ28系統を1961年に栽植し, 草丈, 分けつ数, 出穂期, 花粉稔性および種子稔性などの諸形質を調査した。その結果は次のとおりである。1)主要形質の系統平均値は, 緯度によってかなり変動しているが, その分散は, 各形質とも野生種のジュズダマの方が大きく, とくに草丈の変異程度はハトムギの4倍に近い。2)諸形質の系統平均値は, 概して緯度との間に負の相関および回帰が存在し, 北方系統ほど矮小な早生型が分布しているが, この傾向は野生種のジュズダマにおいて著しく, 緯度にともなう系統平均値の変動も大きい。3)諸形質の系統内変異については, 両種とも概して北方系統ほど, 草丈, 分けつ数などの茎葉形質の変異が小さく, 形質の安定化が認められる。4)花粉稔性は, 高緯度になるにつれて低稔性個体が出現し, 系統内変異も大きい。5)栽培種のハトムギは, 野生種のジュズダマに比べて, 諸形質の地理的変異も, 系統内の個体変異もともに小さく, 比較的安定した種と考えられる。, The origin of genus Coix can be traced to India and South-East Asia. Two main kinds of genus Coix in Japan are Hatomugi (Coix Ma-yuen ROMAN., C. Lacryma-Jobi L. var. Ma-yuen STAPF. etc.) and Juzudama (Coix Lacryma-Jobi L.). It is not clear when Juzudama came over to Japan but it was known pretty early as wild plant, but it is clear from documentary souces that Hatomugi is a comparatively new plant, which came over from China at the biginning of the nineteenth century. Nowadays, these species are distributed throughout Japan as drug and fodder crop (Hatomugi) or wild plant (Juzudama). To investigate geographically the morphological variation in Hatomugi and Juzudama, the present writer had collected many strains of these specics from all part of Japan. The variance of mean of plant height is greater in Juzudama than in Hatomugi and the range of variation is from 72cm to 181cm in Juzudama while in Hatomugi it is from 115cm to 148cm. The plant height of Juzudama is lower at high latitude than at low one, but in Hatomugi this tendency is not manifest. The correlation and regression coefficient between strain mean of plant height and latitude is -0.742^ and -14.541^ in Juzudama and -0.336 and -1.324 in Hatomugi. The mean of number of tillers is greater in Juzudama than in Hatomugi but the correlation and regression coefficient between strain mean and latitude is negative in both species. And in lower latitude Hatomugi heads earlier while at high latitude there are some strains of Juzudama which heads earlier than Hatomugi. The correlation coefficient in this case is about -0.7 and heading becomes earlier by six days with rise of latitude by one degree. Early maturing type of Hatomugi is seen at high latitude but its correlation is not significant. The variation of character within a strain is estimated by means of coefficient of variation. With regard to plant height, number of tillers and heading date in Juzudama, the coefficient becomes less with the rise of latitude and especially in plant height is shown highly significant negative correlation with latitude. From this result it is manifest that the difference of geogrophical or ecological type between wild species and cultivated ones of Coix in Japan is brought about by the difference of date of introduction and method of availing.

ハトムギとジュズダマの正交雑のF_3より, 草丈に関して任意に43個体を抽出し, また, 240cm以上の高稈個体より正交雑について8個体, 逆交雑について7個体をそれぞれ選抜してF_3系統を培養し, 諸形質間の関連性および遺伝力について検討を行なった。1.任意抽出によるF_3の草丈の系統内分散は大きく, F_2のヘテロ性の高いことが推察されるが, 高稈系統ほど系統内変異の程度は概して小さい。2.草丈と諸形質間の遺伝相関は, 表現型相関よりも高く, とくに出穗期との間にはきわめて高い正の遺伝相関が, 分けつ数との間には負の高い遺伝相関がそれぞれ認められる。しかし, 種子稔性との間には相関は認められない。3.諸形質の系統平均値の親子相関による遺伝力は, 草丈で+0.853,出穗期で+0.801ときわめて高く, 分けつ数にも+0.494の有意相関が認められる。花粉稔性および種子稔性は, F_2の低稔性個体の稔性が著しく向上するために, 親子相関はきわめて低く現われるものと考えられる。回帰による遺伝力は, 概して相関による場合よりも低く, 分散分析による場合は, 相関とほぼ同程度である。以上の結果は, 本雑種の多収性の高稈系統が, いずれも晩生系統であることを示すものである。4. F_2の高稈個体の選抜によって培養したF_3系統においては, 親子相関および回帰による諸形質の遺伝力は概して低いが, 出穗期には比較的高い正の相関と回帰が認められる。また, 草丈と出穗期との間には, 任意抽出系統群におけると同様に正の有意相関が認められる。5.草丈の遺伝獲得量より推定した遺伝力は概して低く, 正・逆交雑ともほぼ0.4程度を示すにすぎない。このことは, 本雑種における初期世代の選抜効果が低いことを意味する。6.以上の結果より, 本雑種後代に, 系統内の草丈分散が小さく, 高稈性でかつ栄養生長期間の長い晩生系統を育成する可能性はきわめて高いと考えられる。, The present paper deals with the investigation on the variation and heritability of some morphological characters of F_3 strains between Hatomugi (Coix Ma-yuen Roman.) and Juzudama (Coix Lacryma-Jobi L.). F_3 strain was bred out of 43 F_2 individuals of random sampling and 15 selected tall plants. The mean of plant height of F_3 strain were distributed uninterruptedly over between 110cm and 250cm. The coefficient of variation of plant becomes less in tall strain and the correlation coefficient was at -0.823. The phenotypic and genetic correlation between plant height and some other characters were calculated by means of analysis of variance and analysis of covariance. As a results, plant height was proved to have a negative correlation with number of tillers but a high positive one with heading date. Heritability of character was estimated by means of correlation and regression between F_2 individual and F_3 strain and more over analysis of variance, and heritability appeared comparatively high through estimation by means of correlation. Heritability estimated by means of correlation in plant height and in heading date was very high, marking more than 0.8,and in number of tillers it marked about 0.5. But as for pollen and seed fertility, heritability can scarcely be recognized because of recovery of fertility in F_2 individual which is of poor fertility. In F_3 strain bred out of selected tall F_2 individual, positive correlation (0.5) and regression (0.5) between F_2 individual and F_3 strain were recognized in heading date, but in other characters the correlation and regression were not remarkable and selection of early generation is not effective. Thus, it can be expected that we can breed up a tall, lately maturing strain of high yielding ability out of later generations of this hybrid.

1,Zea属とCoix属との属間交雜に於ては, Zea×Coixの交雜は不成功であるが, Coix×Zeaの交雜は成功する。本研究の結果によれば雑種々子獲得率は6.2%であつた。2,これら属間交雑のCrossabilityは全くその柱頭上に於ける花粉の発芽能力によるものと思われるが, その理由は未だ明かではない。3,本実験の結果獲得された雑種々子は少量の為, その稔性は未だ検定せられて居ない。4,今後引続き花粉の発芽, 花粉管の伸長と授精現象及その胚の発育状態と交雑成功歩合との関係を明かにし, 併せて雑種々子の稔性及びその子孫に於ける細胞遺伝学的研究, 並びにこれら両親作物の複二倍体の育成等, 本来の育種学的研究へ展開せしめなければならない。, 1. In the intergeneric hybridization between the genus Zea and Coix, the combination of Zea×Coix was unsuccessful, but the reciprocal combination Coix × Zea was successful and some F_1 hybrid seeds were obtained in this experiment and the successful percentage was about 6.2%. 2. In this intergeneric hybridization the crossability between the two genera will be probably due to the germinating ability of pollen on the stigma with each other, but the reason about this problem is not clear up to date. 3. The fertility of F_1 hybrid seeds, obtained in this experiment, is not tested now owing to the small quantity. 4. Hereafter we will clear the relations between the success of this intergeneric hybridization and the germinating ability of pollen on the mutual stigma, the growth of pollen tube, the fertilization between them, and the development of embryo; and will study the fertility of F_1 hybrids and the cytogenetical investigations about their progenies, and then will expand this study, for example, from the breeding angle to produce some amphidiploid crops.