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Studies on the bush formation in hillside tea fields
Get PDF茶樹の更新は,生産力を保ち,茶園管理の作業性を確保する面から樹高を低く維持するために行われるが,強いせん枝は一時的に収量が減少する。傾斜地茶園では,うねの山側と谷側部で新芽の生育が均一でないことが多く,可搬型摘採機を用いる場合,谷側部の樹高が高いと機械を高く持ち上げなければならず,困難な作業となる。そこで今回,中切りと深刈りを併用した樹形改良せん枝を行ったところ,中切りほどは摘採面幅を狭くすることなく,翌年一番茶芽の伸びが良く,茶樹の更新効果が認められた。傾斜地茶園における樹冠面の形状は,気温分布への影響を通じて一番茶収量をも左右する場合がある。改良樹形は,これまでの弧状樹形に比べ,うねの山側部と谷側部の温度差が少なく,低温の極値も高く,気象災害軽減上も有利な樹形であると考察した。また,谷側部を斜面側に角度をつけた更新方法にすることによって,摘採,せん枝,特に薬剤散布の作業性に優れた樹形となった。Causes of differences in growth of tea between the upslope sides and the downslope sides of hedges in hillside tea fields and the methods to reduce them are studied. In the arc shaped bush formation, it was found that tea grew slower on the downslope sides than on the upslope sides. The air temperature around the tea bush in winter, the daily minimum temperature, was lower on the downslope sides of hedges than on the upslope ones. The arc shaped bush formation along slopes that are pruned away deeply has less difference in the temperature of canopy surface and less difference in the growth. This method showed good effects. In addition, the operation became more efficient.E9KJ00004074158論文Articl
Confirmation of Symptom Reproduction in Mume Leaf Margin Necrosis Disease on Prunus mume (cv.Nankou) by Sap Inoculation with Causal Two Viruses, Cucumber Mosaic and Prunus Necrotic Ringspot-like Viruses.
Get PDFわが国有数のウメの産地,和歌山県紀南地方のウメ品種南高に発生している"ウメ葉縁えそ病"(茶がす症)がCucumber mosaic virus(CMV-Um)およびPrunus necrotic ringspot virus類似ウイルス(PNRLV)の重複感染によることを証明する目的で,り病樹から分離された,これら2ウイルスをウメ品種南高に混合接種して病徴の推移を調べた。その結果,萌芽の遅延,不完全花の高率発生,葉脈間の黄化による濃淡斑,全葉の黄化,葉縁部のえそ,早期の落葉など本病の病徴がおおよそ再現された。PNRLV単独接種では病徴は軽く,CMV-Um単独接種では健全対照樹と大差はなかった。以上から本病はこの両ウイルスの重複感染によるものと結論された。なお,花器の異常として雌蕊の発育不全が不稔の主因と思われることを示唆する結果が得られた。Mume leaf margin necrosis (mume leaf edge necrosis) disease, which has occurred in the southern district of Wakayama Prefecture, a major area for mume fruits production in Japan, was tested for symptoms expression by sap inoculation of causal viruses to original mume plantlets cv.Nankou grafted onto Nankou seedlings. Tobacco leaf tissues infected with Cucumber mosaic virus (CMV-Um) and Prunus necrotic ringspot-like virus (PNRLV) isolated from diseased mume plants in Wakayama were macerated, respectively, in phosphate buffer added with nicotine and sodium DIECA. Inoculations were made by slashing the surface of green shoots with a surgical knife dipped into inoculum. Eaqualy mixed saps of CMV-Um and PNRLV and both of single virus were inoculated to each 5 potted plantlets, respectively. Inoculated plants with mixed sap showed the symptoms of delayed sprouting, leaf interveinal chrolosis, leaf rolling, leaf margin necrosis, earlier yellowing of leaves and defoliation, and higher percentage occurrence of deformed flowers. These symptoms are similar to the naturally infected plants in the fields. The symptoms in the PNRLV plot indicated slighter symptoms than the mixed one, the CMV-Um plot showed almost symptomless and the buffer-inoculated control plot remained healthy. These results were evidence that the disease is caused by multiple infection with two viruses described above. Infertility of pistil in deformed flower suggests the major cause of barrenness in the diseased plant.E3KJ00004074169論文Articl
Changes of moisture content in tops and tubers of Dioscorea alata L. in different growth stages
Get PDF関東地域で収穫可能なダイジョの1品種を用いて,地下部の塊茎のみならず塊茎デンプンのソースである地上部の茎葉における生長過程の含水率の変化を調べた。その結果,生長時期の推移に伴う茎葉含水率と塊茎の含水率の変化には顕著な差異が認められた。すなわち,茎葉の含水率は生長期間の大半を通して緩やかに減少するが,塊茎の含水率は肥大初期に急速に減少し,その後横這いから緩やかな減少傾向を示した。塊茎では,肥大初期にはその組織が主に若い柔組織細胞で構成されているため水分含量が高いが,肥大が旺盛になるにつれてデンプンの蓄積が進み,それに伴って含水率が低下したものと推測された。このことから,ダイジョの塊茎の含水率の推移は,品種の塊茎成熟度の特性を評価する有効な方法となる可能性が考えられた。Greater yam (Dioscorea alata L.) is one of the yams and still a staple food tuber crop in parts of developing and self-sustaining agriculture in tropical Asia. Yam tuber contains high moisture content, which changes during growth stages. The present research investigated changes of moisture content in tubers and tops of an early cultivar, which is able to riper in the Kanto Metropolitan area. According to the results, remarkable differences were observed in changes of moisture content of tubers and tops of growing plants. Moisture content of tops gradually decreased throughout whole growth stages, while that of tubers rapidly decreased at the early stage of growth and thereafter tended to reduce gradually. In the earlier stage of growth, tubers consisting of young parenchyma seems to maintain higher moisture content. But as the growth of tuber progresses, starch is accumulated and moisture content of the tuber is thought to be reduced. From these results, the changes of moisture content in tubers will be an useful indicator for tuber maturity.E4KJ00004074170論文Articl
Powdery Mildew Fungi and Their Host Plants in Ryukyu Islands
Get PDF琉球諸島におけるうどんこ病の発生状況とその病原菌に関する報告は少ない。本研究では2000年と2001年の各3月に沖縄,石垣両島の栽培植物および野生植物上における同病の発生状況を調査し,1種の新宿主(ゲッキツ)と,わが国では未記録の2宿主(ヘチマ,ハマアズキ)を含む9科17属20種の植物でうどんこ病の発生を認めた。これらの病原菌は,そのアナモルフを精査し,下記に列挙した4属10種と同定したが,ナスとゲッキツ両菌については所属を決定できなかった。1.Sphaerotheca fusca : アキノノゲシ,シロバナセンダングサ,スイカ,セイヨウカボチャ,センナリホオズキ,ツルレイシ,ヒマワリ,ヘチマ上 2.S. phaseoli : ハマアズキ上 3.Erysiphe cichoracearum : ノゲシ上 4.E. heraclei : オヤブジラミ,ボタンボウフウ上 5.E. malloti : アカメガシワ上 6.E. pisi : エンドウ上 7.E. sordida : オオバコ上 8.Microsphaera russellii : カタバミ上 9.Oidium latisporum : シロタエヒマワリ上 10.O. sonchi-arvensis : ハチジョウナ上 11.O. sp. : ゲッキツ,ナス上 今回の調査結果に過去の記録を加えると沖縄県では少なくとも13科22属24種の宿主に8属14種のうどんこ病菌が発生する。Reports describing the powdery mildew fungi and their host plants in Ryukyu islands are scarcely known. In march 2000 and 2001,researches were conducted to elucidate the occurrence of the fungi on cultivated and wild plants in Okinawa and Ishigaki islands. Throughout the survey, the powdery mildew fungi of 10 spp. belonging to four genera were found on the plants of 20 spp. almost all of which were new records in the localities. Among them, the disease was found on one new host, Murraya paniculata, and also on sponge cucumber (Luffa agegyptica) and Vigna marina on which the disease is off record in Japan. The fungi on the following plants were identified as the anamorph of the taxa shown below : 1. Sphaerotheca fusca on Bidens pilosa var. minor ; Citrulus vulgaris ; Cucurbita maxima ; Helianthus annuus ; Lactuca indica var. laciniata ; Luffa agegyptica ; Momordica charantia ; Physalis angulata. 2. S. phaseoli on Vigna marina. 3. Erysiphe cichoracearum var. cichoracearum on Sonchus oleraceus. 4. E. heraclei on Peucedanum japonicum ; Torilis scabra. 5. E. malloti on Mallotus japonicus. 6. E. pisi on Pisum sativus. 7. E. sordida on Plantago asiatica. 8. Microsphaera russellii on Oxalis corniculata. 9. Oidium latisporum on Helianthus argophyllus. 10. O. sonchi-arvensis on Sonchus brachyotis. 11. O. sp. on Murraya paniculata ; Solanum melongena. The powdery mildew fungi of 14 spp. have been described on the plants of 24 spp. in Okinawa-pref.,including the records by other authors.E11KJ00004074177資料Research Dat
Studies on the Origin of Colletotrichum acutatum, Capulicherry Anthracnose Pathogen
Get PDF東京都世田谷区の東京農業大学世田谷キャンパス内の高層建築物とコンクリート塀に囲まれた中庭に,1978年種子によりエクアドルから導入されたカプリチェリー(Prunus capuli)が植栽されている。1997年このカプリチェリーにColletotrichum acutatumによる炭疽病の発生が確認された。同病の感染源に関して知見を得るため,その中庭に生育する種々の植物葉から分離される炭疽病菌について調査・検討を行った。これまで未記録の宿主植物を含む各種植物の展開葉からは,褐色斑点や褐変部の有無に関わらずC. acutatumが高頻度に分離され,分離菌株はその分離源植物の違いに関わらずほぼ共通の宿主範囲を有した。調査地内の各種植物間では共通の宿主を経由してC. acutatumが互いに感染・蔓延していることが強く示唆されるとともに,かなり以前からC. acutatumが国内に蔓延している可能性が考えられた。カプリチェリー炭疽病は病原菌の侵入経路が不明とされていたが,以上の結果からカプリチェリー導入前後に同菌に感染した植物がこの中庭に持ち込まれて周囲の植物に同菌が発生または潜在感染し,さらにそれらの感染植物体上のC. acutatumが同病の最初の感染源となった可能性が示された。A capulicherry (Prunus capuli) tree was introduced by seed in 1978 from Equador in the quadrangle surrounded by tall buildings and the fence in Setagatya campus of Tokyo University of Agriculture, Setagatya-ku, Tokyo and found to be infected with Colletotrichum acutatum whose origin was unknown. Pathogenicity of the anthracnose fungi isolated from various plants grown at the quadrangle were investigated to clarify the origin of the capulicherry anthracnose pathogen. C. acutatum was frequently isolated from the fully expanded leaves of many species of plant including new hosts with or without brown lesion and/or area. The isolates of C. acutatum had almost common host range in spite of their source plant species. These results and previous reports suggested that the plants grown in the quadrangle were infected with C. acutatum through common host plants and C. acutatum had been distributed in Japan at least before 1980. It seemed from consideration mentioned above that the origin of capulicherry anthracnose pathogen had been introduced with some other infected plants externally and /or latently that surrounded the tree before or after introduction of the tree.E1KJ00004074178論文Articl
Genetic differentitation among Kandelia cadel and Bruguiera gymnorrhiza populations in the Southwest Islands, Japan
Get PDF南西諸島におけるメヒルギ,オヒルギ集団間の遺伝的分化を調査した。南西諸島はこの2種の分布域の周縁部に位置し,集団は比較的小さい。メヒルギでは3遺伝子座,オヒルギでは6遺伝子座のマイクロサテライトマーカーを用いた遺伝分析から2種ともに高い遺伝的変異が示された。メヒルギの対立遺伝子の有効数は2.152,ヘテロ接合度は0.409であった。一方,オヒルギの対立遺伝子の有効数は1.593,ヘテロ接合度は0.318であった。集団間の遺伝子分化係数は高く,メヒルギで0.316,オヒルギで0.380であった。メヒルギの遺伝的多様性は,沖縄本島,奄美大島が西表島よりも大きかった。また,オヒルギの遺伝的多様性は,西表島が沖縄本島,奄美大島よりも大きかった。2種の遺伝的多様性の水準は,集団の規模と地域性に関連すると考えられる。The genetic differentitation of the mangrove tree species Kandelia cadel and Bruguiera gymnorrhiza in the Southwest Islands of Japan was investigated. These island are located at the periphery of the distribution area of the two species, and their populations are relatively small. Genetic analyses using microsatelite marker of 3 markers in Kandelia cadel and 6 markers in Bruguiera gymnorrhiza revealed very high genetic variation in both species. At the species level, the average effective number of alleles per locus was 2.152, and the average expected heterozygosity was 0.409 in Kandelia cadel. The corresponding figures for B. gymnorrhiza were 1.593 and 0.318, respectively. The coefficients of genetic differentiation among the populations were high (G_=0.316 for K. cadel and 0.380 for B. gymnorrhiza). The genetic variationn and habitat area of K. cadel on the lslands Amami and Okinawa are greater than on Iriomote island. The genetic variation and habitat area B. gymnorrhiza is greater on Iriomote island than the islands Okinawa and Amami. The level of genetic variation in both of the species might be related to their population size and locality.E9KJ00004074195論文Articl
Changing of Employment System and the Efficiency of Production in the Sake-Brewing Industry : A Survey of Wages of Sake-Brewing Workers in the Kanto-Ko-Shinetsu Erea
Get PDF清酒製造業は,わが国の伝統産業であると同時にいち早く近代化がなされた産業でもある。しかしながら,清酒製造業では外部労働市場に依存した製造システムである杜氏制度を温存したため,技能労働者の不足がその存立を脅かしている。本報告では,酒造要員不足のなかで,雇用構造を変化させ,労働の内部化(内部組織の形成)を進めている企業と,これに適応できない小規模企業との間に生産効率性の著しい格差がみられることを明らかにした。The Sake-brewing industry is one of the traditional industries and also one of the early modernization industries in Japan. However, the industry is in decline because of the Sake-brewing workers decrease for changing of employment system called Touji system, which is the traditional manufacturing system of Sake. The Sake-industry has kept this system making use of labor market for a long time, however, it is no longer efficient. This report has showed the increase in the difference of efficiency of production between bigger business and small business in the Sake-brewing industry. Bigger businesses have high productivity and efficiency because they are adapting to changes in the employment system by the formation of internal organization (internalization of labors organization). But small businesses have not had high productivity or efficiency because they make use of Touji system without adapting to the changing of the employment system in the Sake-brewing industry.E13KJ00004074199資料Research Dat
Effect of Different Depth of Emergence on Percentage of Emergence, Establishment and Growth of Paddy Rice under the Condition of Nontilling Direct Sowing in Dry Paddy Field
Get PDF不耕起乾田状態での直播栽培において,出芽深度の深浅が出芽・苗立ち・生育に及ぼす影響について,ポット栽培によって検討した。水稲品種コシヒカリを供試し,播種深度1cm区と3cm区を設けて比較した。3cm区では1cm区より出芽速度が約3日遅く,出芽率は約18%低下した。分げつ数は2次分げつにおいて顕著に減少し,植物体は過剰生育が抑制される様相を呈した。その後,3cm区では有効茎歩合は高められ,稈が太くなった。節間の挫折荷重,押し倒し抵抗値が大きくなり,倒伏に対する抵抗性が強まる傾向がみられた。さらに本研究においては,3cm区の登熟歩合・1,000粒重はともに1cm区よりも高く,登熟品質向上がうかがわれた。以上の成果から,深播き栽培の有効性についての考察を行った。This study aims to analyse the effect of different depth of seed sowing on plant growth under the condition of direct sowing in dry paddy field. Using the cultivar, Koshihikari, plots of 1cm depth and of 3cm depth were compared. In the 3cm plot, seed emergence was delayed and the percentage of emergence fall was about 18% compared to the 1cm plot. The tiller number of the 3cm plot decreased especially in the secondary tiller, and the plant showed a tendency to suppress overluxuriant growth. Then in the 3cm plot, the percentage of productive culms increased, and the culms grew thicker, the lower internode became stronger, the resistance to lodging increased. Moreover, the ripening quality such as the percentage of ripened grains, or 1000 grain weight were greater in the 3cm plot than in the 1cm plot.E2KJ00004019072論文Articl
Study on Fruit Cracking of Tomato under Greenhouse Culture
Get PDF収穫直前に発生するトマト果実の裂果について発生要因を探るため,埼玉県滑川町の農業生産法人において3年間の果実収量,裂果率,および当該地域の気象条件を踏まえ,温室内における気象条件の推移と裂果発生との関係について調査検討した。トマト果実の裂果は,例年4月から6月に発生頻度が高くなるが,温室内の気温および湿度が大きく変動する時期であり,1日における,気温および湿度も日ごとに大きく変動する。これら日中の気温および湿度から飽差を算出し裂果発生との関係について検討した結果,日毎の飽差の差と裂果発生との間には正の相関がみられた。このことから,裂果の発生には,飽差の変動が関与している可能性が示唆された。Fruit cracking occurring just before harvesting is one of the most delicate problems in tomato greenhouse cultivation. In this study we investigated the relationship between fruit cracking and meteorological factors in the greenhouse. As a result, it was suggested that the sharp fluctuations of temperature and humidity of the greenhouse were closely associated with fruit cracking. In particular the vapor pressure of deficit (VPD) in the greenhouse calculated from value of temperature and humidity was indicated to have a significant correlation with fruit cracking. Therefore the control of VPD can be a possible countermeasure to suppress Tomato fruit cracking.E3KJ00004088191論文Articl
Effects of Storage Duration of Imported Lily Bulbs at Different Temperatures below Zero on Flowering and Cut Flower Quality
Get PDFオランダから輸入したオリエンタル系`カサブランカ'とLA系`セベコデジール'の球根を-0.5～-2.0℃の氷温帯で温度を変えて貯蔵し,定植期を変えて栽培した時の切り花品質を調査した。2003年3月18日から-1.5℃と-2.0℃で球根を約3,6,8,9,11か月間貯蔵した。ただし,-1.5℃貯蔵区は7月以降,約1か月ごとに温度を0.2℃ずつ上げていき,11月以降の貯蔵温度は-0.5℃一定とした。-2.0℃は一定であり,別に8か月貯蔵では,-1.5℃一定条件で貯蔵する区も設けた。栽培条件は最低夜温15℃とし,7～10月にかけて高温と強光を避けるために50%の寒冷紗を用いて遮光した。`カサブランカ',`セベコデジール'ともに,-1.5℃貯蔵では6か月を過ぎると芽の伸長がみられ,りん片・茎のBrix値が低下した。-2.0℃貯蔵では11か月貯蔵後でも芽の伸長はほぼ抑制され,りん片・茎のBrix値低下も-1.5℃貯蔵に比べ小さかった。LT50値は,-2.0℃貯蔵では-1.5℃貯蔵よりも低く,貯蔵期間が長くなると高くなった。`カサブランカ'では,貯蔵期間が長くなるにつれて切り花の長さと重さおよび花数が減少する傾向にあった。また6か月以上貯蔵すると,異常花と障害葉の発生がみられ,異常花は-1.5℃貯蔵区で,障害葉は-2.0℃貯蔵区でより多く発生した。-1.5℃一定で貯蔵すると異常花の発生は減少したが,障害葉の発生は-2.0℃貯蔵と変わらなかった。これに対し,`セベコデジール'では貯蔵の温度・期間に関わらず切り花の長さと重さにはほとんど差がなく,遮光によるアボーションを除き,花と葉に障害の発生もほとんどみられなかった。以上の結果,オリエンタル系の`カサブランカ'では,球根を6か月以上氷温帯で貯蔵すると採花時の切り花品質が低下するが,LA系の`セベコデジール'では11か月氷温帯で貯蔵しても切り花品質への影響はほとんどないことが明らかになった。Lily bulbs of Oriental hybrid 'Casa Blanca' and LA hybrid 'Ceb Dazzle' imported from Holland were stored at -1.5℃, -1.5℃±0.3℃ or -2.0℃±0.5℃ for various durations from 3 to 11 months beginning on 18 March. At storage temperatures of -1.5℃, bulbs were stored at -1.5℃±0.5℃ from 18 March to early July and thereafter storage temperature was increased by 0.2℃ per month until reaching -0.5℃. After reaching -0.5℃, temperature was maintained at -0.5℃±0.5℃. At storage temperature of -1.5℃±0.3℃ bulbs were stored for only 8 months. After the storage, they were grown in a greenhouse kept at minimum temperature of 15℃ and under 50% shaded condition from July to October to check the quality of cut flowers. In bulbs of both cultivars stored at -1.5℃ for more than 6 months, shoots elongated and Brix values of scales and stems decreased. In contrast, at -2.0℃ elongation of shoots was inhibited and lowering of Brix values of scales and stems was smaller. Estimated median lethal temperature (LT50) of shoots was lower in bulbs stored at -2.0℃ than at -1.5℃ and became higher slightly with longer storage duration at both temperatures. In 'Casa Blanca' prolonged storage at any temperatures reduced the weight and length of cut flowers and the number of flowers. Longer storage for more than 6 months increased the number of abnormal flowers and damaged leaves. More abnormal flowers and damaged leaves were observed at -1.5℃ and -2.0℃, respectively. Storage at -1.5℃±0.3℃ reduced the number of abnormal flowers, but did not change the number of damaged leaves compared to -2.0℃. On the other hand, in 'Ceb Dazzle' length and weight of cut flowers were almost the same and abnormal flowers and damaged leaves were hardly observed irrespective of storage duration and temperatures. However, abortion of flowers occurred in October planting due to low light intensity under shading. These results show that 'Casa Blanca' bulbs cannot produce cut flowers with high quality after storage at temperatures below zero for more than 6 months, but 'Ceb Dazzle' bulbs can be stored up to 11 months.E7KJ00004587987論文Articl