大麦網斑病抵抗性の選抜効果

Selection effectiveness for the resistance to net blotch was estimated by using two sets of F2 and F3 populations derived from the crosses between resistant and susceptible parents. In every F2 and F3 population, disease ratings showed a continuous distribution. As many F3 lines with intermediate resistance had a smaller variance and homozygous genotype, the resistance might be controlled by a few genes. The heritabilities of the disease rating were estimated　by correlation coefficients and regression coefficients between each F2 plant and the descended F3 lines. Another estimate for heritability was calculated by the selection differential in the F2 plants and genetic gain in the F3 lines. Despite the different level of resistance in the resistant parents of the two crosses, the three kinds of heritabilities estimated were similar and ranged from 0.6 to 0.8. Because of the fewer number of genes controlling the disease resistance and the higher heritabilities, selection in a early generation may be effective for net blotch resistance in barlcy.抵抗性と罹病性の両親間の交雑に由来する2組のF2集団とその後代のF3系統を用いて、大麦網斑病における抵抗性の選抜効果を推定した。F3系統の平均値と分散から、病斑指数の分散が小さく、すでに固定した系統が多数存在したので、抵抗性は少数の遺伝子に支配されているとみられた。F2個体とF3系統間の親子相関、親子回帰およびF2の選抜差とF3系統の遺伝獲得量から遺伝率を推定したところ、2組の交雑組合せで抵抗性親の病斑指数は異なっていたにもかかわらず、3種類の遺伝率の推定値はいずれも0.6～0.8の値を示した。遺伝率が高く、しかも関与する遺伝子数であるため、雑種集団で連続変異を示す場合の大麦網斑病抵抗性の選抜はF2からでも効果的とみられた

日本とカナダの春播オオムギから採取した大麦網斑病菌株の病原性の変異

Twenty-two isolates of Pyrenophora teres Drechs. collected from Japanese and Canadian spring barleys were inoculated to 38 barley varieties having various genetic backgrounds. The analysis of variance for the discase ratings showed that there were significant differences both in the virulence of isolates and the resistance of varieties. However, the interaction among isolates and varieties was not statistically significant. Both Finlay-Wilkinson regression analysis and principal component analysis by Additive Main effects and Multiplicative Interaction effects(AMMI)model classified the isolates into three groups,which were different in origins and sympton types. A spot tyte isolate was distinguished from net type isolates by its generally high virulence. A slight pathogenic differentiation was suggested between Japanese and Canadian net type isolates.北海道およびカナダの春播オオムギがら採取した22の大麦網斑病菌株（Pyrenophora teres Drechs.）を世界各地のオオムギ38品種に幼苗接種し、病斑指数によって病原性の変異を検討した。分散分析の結果、菌株の病原力ならびに品種の抵抗性には有意差が認められたが、菌株と品種の交互作用は統計的には有意でなかった。各菌株の反応をFinlay-Wilkinson（1963）の回帰分析によって解析したところ、北海道とカナダの菌株で病原性反応に差が認められた。この傾向はカナダの菌株のうち、通常のNet typeの菌株よりも斑点状病斑を示すSpot typeの菌株で顕著であった（Fig.1）。さらに、菌株と品種の交互作用を詳細に解析するために相互作用と相乗交互作用モデル（AMMIモデル）を適用して交互作用に関する主成分分析を行った結果、各菌株は日本のNet type、カナダのNet type、カナダのSpot typeの3群に分けられた（Fig.1）。各菌株について群間ならびに群内の相関係数を算出したところ（Table5）、Net typeの菌株相互の相関係数は0.601～0.969と相対的に高かったが、一部の菌株と品種の組合わせでは抵抗性反応の逆転がみられた（Fig.4）。一方、Spot typeの菌株とNet typeの菌株の相関係数は0.302～0.538と低く、両者の病原性は多少異なることが示された。このような一部の菌株と品種の間に認められる弱い交互作用は、抵抗性を支配する主働遺伝子の特異的な反応が、いわゆる圃場抵抗性を支配する微働遺伝子の作用によって修飾された結果と考えられる

Establishment of a Seedling Test for Resistance to Net Blotch in Barley and a Search for Resistant Varieties

大麦網斑病は糸状菌の1種であるPyrenophora teres Drechs.の感染によって葉身、葉鞘等に網目状の病斑を生じ、子実の登熟低下によって減収する共に、ビールオオムギにおいては醸造品質であるエキス分が低下する重要病害である。本病害は世界各地のオオムギ栽培地帯のうち主として温暖・湿潤な地域に分布しており（Shipton　et　al.1973）、近年、連作や灌漑によって被害が増大しつつある（Mathre 1982）。我国においては従来からその存在が確認されていたものの、登熟後期の活性の衰えた葉に生じる病害として重要性は認識されていなかった。しかし、最近、北海道、鳥取県、鹿児島県などのビールオオムギ栽培地帯で局所的な激発事例が確認されている。（佐藤、未発表）。本病害に対する防除法としては種子消毒ならびに殺菌剤の茎葉撒布が有効であるが、その効果は完全ではない。また、茎葉撒布はコストが高く、環境汚染の問題もあるので、最も有効で経済的かつ安全な防除法は抵抗性品種を栽培することと言っても良い。従来、本病害の積極的な抵抗性育種は行われていなかったが、最近は抵抗性を有する品種も育成されている（Metcalfe 1987）。抵抗性品種を育成するためには、遺伝資源ならびに雑種後代を効率よく評価、選抜するための検定方法を確立しなければならない。本病抵抗性の検定方法としては幼苗検定法、圃場検定法が考案されて広く用いられているが（Buchannon and McDonald 1965, Holtmeyer and Webster 1981）、環境条件の変化によって抵抗性が変動する事例が報告されているので（Khan and Boyd 1970, Tekauz 1986）、抵抗性を確実に評価するための安定した検定条件を設定する必要がある。抵抗性に関する遺伝資源についてはSchaller and Wiebe （1952）、Dessouki et al.（1965）およびBuchannon and McDonald （1965）等がそれぞれ数千品種を評価し、中国東北部、トルコおよびエチオピアなどに抵抗性の遺伝資源が豊富であること報告している。それらの品種のいくつかについては、抵抗性の遺伝子分析が行われており（Bockelman et al. 1977, Davis et al. 1990）、本病抵抗性育種の交配親として使用されている（Tekazu and Buchannon 1977, Moseman and Smith 1985）。岡山大学資源生物科学研究所大麦系統保存施設は世界的にも貴重なと東アジアの遺伝資源をはじめ五千余の保存品種を有するが、著者らは大麦網斑病の幼苗検定法を確立し、これらの品種の抵抗性を評価したので報告する。A seedling test was developed and used to evaluate the resistance to net blotch of more than five thousand barley varieties preserved in the Barley Germplasm Center, Okayama University. 1) Disease ratings (Tekauz 1985) of varieties varied depending on the temperatures after inoculation. However, these was no change for rank of varietal resistance in the temperature range from 15 to 25℃, which covers the normal growing temperature for barley. 2) There was little variation in the level of seedling resistance of varieties under different levels of fertilizer application. 3) A high positive correlation was observed in the disease ratings obtained after second-leaf and fourth-leaf stage inoculations of the 2,230 barley varieties. Inoculation at the second leaf stage was superior to fourth leaf inoculation since it resulted in a wide range of disease ratings and required a shorter testing period. 4) The disease ratings observed appeared to be a stable genetic character sine the error standard deviations were only 0.4 to 0.8 in plots and 0.5 to 1.0 in plants, when four or five plants per plot were tested. 5) The disease ratings of 5, 102 varieties when tested with isolate K105 showed continuous variation with a mode in the resistant range. By comparing the average disease ratings for varieties from different regions, resistance was found to be higher in the Ethiopean and Koreaan barleys and lower in European, Tukish and South-east Asian types. However. there were obvious difference between varieties within a region, such as between two-rowed and six-rowed varieties from Japan and between covered and naked varieties from Nepal. 6) When varieties were classified into the principal morphological or physiological types of barley, the two-rowed, spring habit, and western-type in rachis brittleness showed significantly lower levels of resistance than the contrasting types for each of these classifications. In particular, the group having two-rowed, spring-habit, western-type, covered characteristics, which was common among malting barley varieties had lower resistance, while a group of six-rowed, autumn-habit, naked barleys showed higher resistance. Comparisons using isogenic pairs for row-types and hull-types did not reveal any obvious differences between each pair, indicating that the differences between groups were not probably due to the pleiotropic or likage effects of genes but to the different genetic backgrounds of these varieties

Sources of Resistance to Net Blotch in Barley Germplasm

Net blotch caused by a fungus Pyrenophora teres Drechs. is a common disease in barley. Its source of resistance has been screened by many researchers by field evaluations or seedling tests inoculating a single isolatc. Since the pathogcnic variation of isolates has been reported in net blotch, resistance of the varieties to the disease may be different among the isolates with different pathogenicities. In this study, the pathogenic variation was examined and the varietal variation of the resistance was evaluated by inoculating with four P. teres isolates collected from Japan and Canada to more than 2,200 barley varieties of the world collection preserved at the Barley Germplasm Center of Okayama University. A preliminary inoculation test showed that the disease rating was affected little by the inoculation seasons. Disease ratings of varieties showed a continuous variation with a single mode in the resistant range in each of the four isolates. However, the correlation coefficient between Japanese isolate K105 and Canadian isolate WRS102 was as low as 0.55, indicating a slight pathogenic differentiation between these isolates. Significant correlation coefficients (r=.55~.78) among the ratings of isolates indicated that the pathogenicity to the varieties was rather similar and that the pathogenic differentiation was small among the four isolates tested. In general, varieties from Ethiopia, North Africa and Korea were more resistant than those from other regions. Varieties from Turkey and Europe were susceptible to Japanese isolates, while Nepalese varieties were susceptible to Canadian isolates. Twenty of 25 varieties which were resistant to the isolate K105 but susceptible to the isolate WR102 were from Nepal and most of those were Oriental-type (Bt bt2) in brittleness of rachis. These findings revealed an example of regional concentration of resistant gene in net blotch.日本ならびにカナダで採取した大麦網斑病菌4菌株を、岡山大学資源生物科学研究所大麦系統保存施設の保有する2,200あまりの品種に接種して、各菌株に対する抵抗性遺伝子源を評価すると共に病原性の分化を検討した。結果の概要は以下の通りである。1）3回にわたって44品種に4菌株を接種した予備試験の結果、病斑指数の品種変異は極めて大きく、品種の抵抗性に対する接種時期の影響は小さかった。2）供試4菌株に対するオオムギ品種の抵抗性の頻度分布はいずれも連続的で、そのピークは抵抗性側であった。各菌株間の病斑指数は有意な正の相関関係にあり、菌株間の病原性の分化は小さかった。3）各菌株に対する抵抗性遺伝資源はエチオピア、北アフリカおよび朝鮮半島に多かった。一方、日本で採取した2菌株に対する罹病性の品種はトルコおよびヨーロッパに多いのに対して、カナダで採取した菌株に対する罹病性の品種はネパールに多かった。また、ネパールに由来する品種の病斑指数は、日本の2菌株に対しては抵抗性と罹病性の2群に分かれたが、カナダの2菌株に対しては連続的な分布を示した。特に、カナダの菌株WRS102に対するネパール由来の品種の反応は、強度の抵抗性を示す品種がなく、ピークが罹病性側に片寄っており、日本の菌株に対する反応とは大きく異なった。4）日本で採取したK105とカナダで採取したWRS102の病斑指数の菌株間相関係数は、4菌株の組合せの中で最も小さく、K105とWRS102の病原性は多少分化していた。なお、K105に抵抗性でWRS102に罹病性の品種は25品種であり、そのうち20品種がネパール由来で、かつ、そのほとんどが小穂脱落性東亜型を示した。従ってK105に抵抗性でWRS102に罹病性の遺伝子は、ネパールの東亜型品種に偏在しているとみられる

CAM and NK Cells

It is believed that tumor development, outgrowth and metastasis are under the surveillance of the immune system. Although both innate and acquired immune systems play roles, innate immunity is the spearhead against tumors. Recent studies have revealed the critical role of natural killer (NK) cells in immune surveillance and that NK cell activity is considerably influenced by various agents, such as environmental factors, stress, foods and drugs. Some of these NK cell stimulants have been used in complementary and alternative medicine (CAM) since ancient times. Therefore, the value of CAM should be re-evaluated from this point of view. In this review, we overview the intimate correlation between NK cell functions and CAM agents, and discuss possible underlying mechanisms mediating this. In particular, neuro-immune crosstalk and receptors for CAM agents are the most important and interesting candidates for such mechanisms

Comparison between shoot Regeneration Ability in Calli Derived from Immature Embryos of Wild and Cultivated Barley

The variation in shoot regeneration obility of calli derived from immature embryos was examined in 95 wild strains, 82 of which were of Hordeum spontaneum and 13 of which were H. agriocrithon, and 87 cultivated varieties collected from various countries or regions of the world. In 85 strains of the wild species, a number of calli regenerated shoots, and their proportion ranged from 1.2% to 75.7%. The average percentage of shoot regenerating calli was 21.7% among the strains that formed calli, 11.5% of which regenerated green and 10.2% albino shoots. On average, 21.4% and 23.9% calli regenerated shoots in H. spontaneum and H. agriocrithon, respectively and there was no significant difference between these values. A significant difference in the percentage of shoot regenerating calli was found among six variants (dawense, ishnatherum, laguncliforme, paradoxon, proskowetzii, spontaneum) which were comprised in H. spontaneum. In 73 varieties of cultivated species, there were shoots regenerating calli likely to wild species, and their proportion ranged from 3.2% to 85.5%. The average percentage of shoot regenerating calli was 25.4%, 22.0% of which regenerated green and 3.4% of which regenerated albino shoots. There was a significant difference in percentage of green shoots regenerating calli against shoots regenerating ones between the wild (53.0%) and cultivated species 886.6%). The two kinds of non-brittle rachis genotypes, Bt bt2 and bt Bt2 are one of the key characters distinguishing the oriental and occidental types of cultivated barley. The average percentages of shoot regenerating calli were 16.2% and 32.3% for the genotypes Bt bt2 and bt Bt2, respectively, suggesting that there is a geographical variation in the shoot regeneration ability of calli in the cultivated species. By contrast, the oriental and occidental strains of wild species showed no difference in the shoot regeneration ability of calli. The geographical variation of shoot regeneration ability differed significantly between wild and cultivated species. This suggests that the geographical variation of shoot regeneration ability occurred after the cultivation of the barley was established.本研究ではオオムギ近緑野生種Hordeum spontaneum82系統とH.agriocrithon13系統、計2種95系統および世界各地の栽培種87品種を供試して、未熟胚由来カルスからの不定芽再分化能を調査し、近緑野生種と栽培種における再分化能の品種変更およびその地理的分化を比較した。近緑野生種では95系統中94系統がカルスを形成し、そのうち85系統（90.4％）が不定芽を再分化して、不定芽再分化率は系統によって1.2％から75.7％まで幅広く変異した。カルスを形成した94系統における不定芽再分化率の平均値は21.7％、緑色不定芽再分化率は11.5％、アルビノ不定芽再分化率は10.2％であった。H.spontaneumとH.agriocrithonの不定芽再分化率の平均値はそれぞれ21.4％と23.9％で、有意差は認められなかった。しかし、H.spontaneumに含まれる6品種（dawense, ishnatherum, laguncliforme, paradoxon, proskowetzii, spontaneum）の間では不定芽再分化率に差異が認められた。栽培種では供試品種のすべてがカルスを形成し、そのうち73品種（83.7％）が不定芽を再分化して、不定芽再分化率は品種によって3.2％から85.5％まで幅広く変異した。供試品種全体の不定芽再分化率の平均値は25.4％、緑色不定芽再分化率は22.0％、アルビノ不定芽再分化率は3.4％であった。このように、不定芽再分化率に対する緑色不定芽再分化率の占める割合は栽培種で86.6％、近緑野生種で53.0％となり、両者に大きな差が認められた。供試した栽培種を小穂非脱落性に関する遺伝子型によって東亜地域に多く分布するBt bt2型と西域に多く分布するbt Bt2型に分けて不定芽再分化率を比較すると、Bt bt2型の平均値は16.2％、bt Bt2型の平均値は32.3％となり、bt Bt2型の不定芽再分化率が有意に高く、地理的分化が認められた。しかし、近緑野生種では不定芽再分化能の地域間差がみられないので、オオムギの祖先種が栽培化されてから不定芽再分化能の地理的分化が生じたものと考えられる

Character Expression and Inheritance of a "Short Upper Leaves" Mutant in Barley

A mutant which devolops an extremely shortened flag leaf and shorter upper leaves was obtained from the progeny of 90 KR of gamma-ray irradiated Fuji Nijo, a malting barley variety. This mutant was controlled by a single partial dominant gene named Sul (short upper leaves). The character expression and the inheritance of the gene were investigated in this study. Sul shortened the flag leaf and upper several leaves and uppermost internode length, while it did not affect the length of spike, lower leaves and the second or lower internodes. A reciprocal translocation of the chromosomes was observed in this mutant line, and the Sull gene was linked with the V (two-rowed) gene on chromosome 2, and also linked with the breaking point of the reciprocal translocation. Small leaf area caused by the Sull gene might reduce the mutual shading and the transpiration of the leaf canopy at the later growth stages.二条オオムギ品種ふじ二条にガンマー線を3代にわたって合計90KR累代照射した後代から上位の数葉が短縮し、特に止葉は痕跡的に短くなる変異体を見出し、その形質表現と遺伝性を解析した。1）この変異体では基部の数枚の葉身の長さは原品種と変わらず、上位の数葉、特に止葉が強く短縮する。穂長および小穂段数は原品種と変わらない。2）この変異体は不完全優性の主働遺伝子Sul（short upper leaves上位葉短縮型）に支配される。3）Sul遺伝子は第2染色体に座乗するν/V（条性）遺伝子と連鎖し、また相互転座点と密接に連鎖している。4）この変異体は登熟期における葉面積が小さいので相互遮蔽が少なく、また収穫指数が高まって多肥密植栽培で多収となる可能性があり、また、蒸散量が少なく、半乾燥条件に適応することが期待される

Diallel Analysis for the Percentage of Grains with Hull Rupture in F2 Populations of Two-rowed Barley

Half diallel F2 populations crossed among eight two-rowed barley varieties with warious percentages of hull ruptured grains were raised to analyze the inheritance of the trait. The percentage of grains with hull rupture varied from 0 to 87% among the parents. The diallel analysis revealed the following: the trait was predominantly controlled by the additive genes, and the dominance effect of some parents was also significant. However, the epistatic effect of the genes was not significant. The average dominance was 0.97. The heritability value was estimated as 0.57 and 0.91 in a narrow and a broad sense, respectivelly. The percentage of grains with hull rupture showed continuous and transgressive segregations in 28 F2 populations derived from half diallel crosses among eight parents. Heritability of the trait in a broad sense was 0.43~0.80(0.65 on average) in 28 F2 populations.二条オオムギにおける裂皮粒歩合の遺伝子を解析するために、裂皮粒歩合が大きく異なる8品種・系統の間で総当たりの交雑を行い、逆交雑を除く28組合せのF2集団とその親を供試して、裂皮粒歩合の遺伝子を調べた。片面ダイアレル分析の結果、裂皮粒歩合の遺伝子にはエピスタシスが認められず、単純な相加優性モデルが適合した。全体として裂皮粒歩合の低い方が部分優性と見られ、その平均優性度は0.97と推定された。裂皮粒歩合の遺伝率は狭義で0.58、広義で0.91と推定された。28組合せのF2集団の裂皮粒歩合はいずれの組合せにおいても連続的な分離を示し、また、超越分離が認められた。F2集団の平均値と両親品種の平均値の相関は高く、雑種集団における裂皮粒歩合は遺伝子の相加的な作用によって支配されていることが示唆された。28組合せのF2集団における裂皮粒歩合の表現型分散と遺伝分散の割合から推定した広義の遺伝率は0.43～0.80（平均0.65）であった

Inheritance of Phenol Reaction in the Awn of Barley

The inheritance and geographical distribution of the phenol reaction in rice has been investigated intensively. On the other hand, in the case of barley, almost all of the varieties show positive reaction to phenol, and inheritance study of the trait has not yet been reported. We investigated the phenol reaction of ca. 5,000 barley varieties preserved at the Barley Germplasm Center of Okayama University to find about 30 varieties which show a negative reaction to the phenol. These varieties are mainly from Southwest Asia. The reaction of awn was sharpest at all parts of the plant including seeds. The positive reaction must be the prototype of barley, because Hordeum spontaneum, a possible ancestor of the cultivated barley, shows positive reaction. Inheritance and linkage studies were conducted using varieties with negative reaction and linkage testers with positive reaction. Phenol reaction was dominant and showed a clear 3:1 segregation ratio in the F2 populations, indicating the trait was controlled by a single dominant gene Ph(phenol reaction). Linkage study revealed that Ph was linked with four marker genes(three loci) on the chromosome 2 and independent of 13 other marker genes located on the chromosomes except chromosome 2. Ph may be a useful marker gene and an interesting material for molecular-biological studies.オオムギの芒ではフェノールを酸化する酵素の活性が強くが、極めて少数の品種では芒のフェノール着色が見られない。本研究では芒のフェノール着色反応の遺伝性を解析した。結果は次の通り。1）芒のフェノール着色反応は優性遺伝子ph（phenol reaction）によって支配されている。2）Phは第2染色体にe-Ph-liの順で配列している。3）芒、穀皮および果実（果皮）の反応が一致しない場合があるが、これが実験誤差か、それぞれの組織で別個の遺伝子が作用していることによるのかは確認を要する