胚乳の欠除及び粳胚乳の移植が糯稲の性質に及ぼす影響(農学部門)

糯稲種実から胚乳を除去し, またそこに粳稲の胚乳を移植した場合に, 糯稲の性質がどのように変化するかを検討するために, 1957,\u2758及び\u2759年度にわたつて実験を行つた。出穂期, 稈長, 一穂粒数には胚乳の欠除あるいは胚移植の影響が認められる。二・三の例外を除くと, 一般に無処理個体にくらべて胚培養個体, 胚移植個体の順に出穂は晩くなり, 稈長は短かくまた一穂数数は減少する。また次代種実の胚乳内amyloseの含量は無処理区と変らず, 処理による種実の澱粉組成の変化はみられない。しかし, 比粘度は胚欠除, 胚移植の順に低下する。これらの変化は翌年度の植物体には再びあらわれない。このような事実からして, 胚乳の欠除または胚移植がこれらの諸特性の変動をもたらす機作は, かなり複雑であるように思われる。In glutinous rice grains, it is interesting that glutinous starch is found only in their endosperm, while non-glutinous one in embryo as mentioned in our previous report (WATABE & UMEKAGE 1959). This experiment, conducted in 1957,\u2758 and \u2759,was carried to make clear how the characteristics of glutinous rice plant were affected by the growth without the endosperm and with transplanted non-glutinous endosperm. The rice varieties named Heirokumochi (glutinous) and Mogamiwase (non-glutinous) were used for materials, and following results were obtained : - 1) In the cases of the growth without the ndosperm and with the different endosperm, as whole, heading date were more delayed, culm length and number of grains per ear were more decreased than in the controls, notwithstanding glutinous or non-glutinous plant (Table 2 & Fig. 1). 2) Starch in the endosperm from plants under the treatments mentioned above possessed the same ratio of amylose being peculiar to glutinous or non-glutinous grain respectively, so that the constitution of the starch seemed to be constant inspite of the treatments (Table 3). On the contrary, starch viscosity showed the highest values in the controls as compared with those of plants grown without the endosdosperm and with different one. Especially reduction of viscosity was conspicuous among the plants having glutinous embryos as shown in Table 3 and Fig. 2. 3) These changes observed in some characteristics mentioned above, disapeeared in next generation plants grown under usual culture using the seeds of financial year. Thus, from these facts, it was seemed to be complex how the mechanism of the changes affected by the existence of the endosperm

Coix 属の改良に関する育種学的研究 V : ハトムギとジュズダマの雑種 F_2 における遺伝的分離(農学部門)

Coix属植物の2種, ハトムギとジュズダマの正逆交雑F_2における主要形質の分離状態を調査し, 優良系統育成の可能性について検討した。出穂期は正逆交雑とも早晩2群に分離し, 早晩比は10 : 54で, 出穂期を支配する3遺伝子を仮定し, 1種類の場合早生群を, 2種類以上の遺伝子を共存する場合晩生群を出現すると考えることによつて一応説明された。茎葉諸形質の平均値はF_1に比し低下したが, 草丈, 分蘗数および生体重の平均は両親よりかなりすぐれていた。正交雑の花粉および種子稔性は逆交雑よりすぐれたが, その他の形質では交雑方向による差は認められなかつた。形質の変異係数は一般に正交雑が小であつた。草丈の頻度分布は, 両親およびF_1型の3部分にわかれた。広義の遺伝力は, 諸形質とも高い値を示した。諸形質間の表現型相関および遺伝相関は, 正逆交雑とも草丈と葉長, 生体重および出穂期との間, また葉長と葉巾の間にかなり高い正相関が認められ, 遺伝相関は常に表現型相関より高かつた。柱頭色はF_2の分離状態より, 補促的に作用するM, Lなる2遺伝子の存在が明らかにされた。また種皮色および硬度についても, 前者は不完全優性の, 後者は完全優性の1遺伝子によつて支配されることが明確にされた。種皮色および柱頭色と量的形質間の関連性は明らかでないが, 種皮色ではF_1色個体が草丈と葉長でまさり, 柱頭色では, 赤紫色個体は白色個体より草丈, 分蘗数および葉長でややまさり稔性では劣る傾向が認められた。ハトムギは1年性, ジュズダマとF_1は越年性であるが, F_2は約80%が越年した。越年個体の再生草丈は, 高稈個体がややすぐれ, また晩生のジュズダマ型およびF_1型の越年能力は, 早生および矮生のハトムギ型個体に比べ著しくすぐれていた。本実験の結果より, ハトムギとジュズダマの雑種後代において, 茎葉生産量の高い越年性の晩生高稈系統を育成することの可能性の高いことが明らかにされた。The present paper deals with the investigation on the genic segregation in the F_2 generation between Hatomugi (Coix Ma-yuen ROMAN.) and Juzudama (C. Lacryma-Jobi L.). On the heading date, all F_2 plants were segregated in two groups of early and late maturity. The ratio of early and late maturity in the F_2 plants was 52 to 285. So the author presume that the maturity is determined by 3 gene and the late maturity is owing to the 2 or 3 dominant genes. Generally the variations of chracters in F_2 plants were larger than both parents and F_1 plant, but the mean values of plant height, number of tillering and plant weight of F_2 plants were heigher than parents. In the main characters except pollen and seed fertility, there are no significant difference between two combinations of crossing. In the crossing of Hatomugi×Juzudama the coefficients of variation of many characters were lower than reciprocal crossing. Phenotypical and genetic correlation were calculated chiefly between plant height and the other characters. In this result, high correlation was recognized between plant height and leaf length, plant weight, pollen fertility and heading date and between leaf lengtn and leaf width, as positive respectively, but to the number of tillering as negative. The vigorous type for plant height was not recognized in all plants belong early maturity group. The inheritance of qualitative character in this crossing was observed to the stigma colour and seed characters. The stigma colour shows clear red-violet in F_1 plants though both parents have white stigma. The colour of seed coat of Hatomugi, Juzudama and F_1 are brown, white spot on black ground and brown and green stripes respectively, and solidity of seed coat are soft, hard and hard respectively. From results of segregation in F_2 plants the author determined on the genotypes of stigma colour and seed characters as follows. Hatomugi…MMll, jj. Juzudama…mmLL, JJ. (M and L are complemantary factors for stigma colour and J is complete dominance for solidity of seed coat and incomplete dominance for colour of seed coat.) The linkage between some quantitative characters and seed coat colour or stigma colour shows no remarkable tendency, but F_2 plants which have F_1 colour in seed coat were superior than the others for plant height and leaf length. In the stigma colour, the plants which have redviolet were superior than the plants which have white stigma for plant height, number of tillering and leaf length, but inferior for pollen and seed fertility. In our country, Hatomugi is annual plant but Juzudama and its F_1 plant are hibernant plant. The hibernation ability of the F_2 plants belong early maturity group and dwarf type was inferior to the plants of late maturity and Juzudama or F_1 types. From these experimental results, for the improvement of genus Coix, it will be most significant to breed the lines of vigorous types for plant height in the progeny of interspecific hybridization between Hatomugi and Juzudama

Coix 属の改良に関する育種学的研究 (III) : Coix 属及び Zea 属の花粉膜の表面構造について

筆者らは現在改良試験を実施中であるCoix属のハトムギ, ジュズダマ及びそのF_1雑種, 更にその四倍体植物の花粉を, Zea属のトウモロコシ花粉と共に薬品処理による花粉膜の光学顕微鏡的観察と, Carbon Replica法の適用による花粉膜の表面微細構造の電子顕微鏡的観察を行い, 両者の比較を行つた。1.光学顕微鏡的観察 光顕像においては, 供試植物の花粉の間には, 花粉粒の大きさ以外に形態学的差異は観察されなかつた。発芽孔は一つであり, 花粉膜はextineが薄くintineが厚く観察された。また発芽帯周辺は一般に厚膜であり, 花粉の変形, 壌裂は極の方に多い。発芽帯には乳状突起が観察された。2.電子顕微鏡的観察 電顕像による花粉のextexineの微細構造は, 供試花粉ではいづれも微細なspineによつておおわれ, 各種間に明らかな差は認められない。ただCoix, Zea両属間にはspineの大きさにおいて, Coix属内の各種間には形状においてやや差が認められるようである。発芽帯の状態は, トウモロコシでは乳状突起の中心に, spineをもつ隆起部が発達し, ハトムギ及びジュズダマでは共にこの隆起部はなく, わづかなうねりをもち, なお乳状突起には不規則に少数のspineが点在していた。しかし, このspineをもつ隆起部は, F_1及び四倍体植物においては著しく発達していた。発芽帯の孔径は, 四倍体は二倍体に比して著しく大きかつた。一般にCoix属とZea属の花粉表面構造の間には, きわめて高度の類似性が認められた。The morphology of pollen is investigated as a main section of palynology. In the present time the studies on the surface structure of pollen are paid special attention to make progress of the pollen analysis. The present paper deals with the results of microscopic and electromicroscopic investigations on the surface structure of the pollen membrane. The materials used in this studies are the pollen of Zea mays, Coix Ma-Yuen, C. Lacryma-Jobi, F_1 plant (C. Ma-Yuen×C. Lacryma-Jobi), 4x F_1 plant and 4x C. Ma-Yuen. The pollen used in the microscopic observation was treated by HCI and NaOH previously and electromicroscopic observation was based on the carbon replica method. 1. Microscopic observation : The morphological difference of pollens between the material plants was not recognized except the diameter of these pollen grains. The pollen of Zea and Coix plant are apaturate pollen similarly other gramineae plants. The extine of pollen membrane was thin but the intine was observed very thickly, These pollens have thick membrane around a germinal zone, for that reason the transformation and the bursting of pollen occurs near the pole of pollen, In germ pore of pollen grain the papilla was observed slightly. 2. Electromicroscopic observation : According to electromicroscopic observation, the extexine of pollen membrane was covered with fine spinules, there were no significant differences between the material plants on the surface structure of the pollen membrane. It is, however, obviously to the slight difference were recognized in the size of spine between the genus Coix and Zea, and in the shape of spine between the each plants in genus Coix. In the state of germ pore, there are fairly different between the material plants. In the germ pore of Zea pollen, the protrusion with fine spinules was well-developed in the central part of papilla, on the contrary, in the Coix Ma-Yuen and C. Lacryma-Jobi a few spines are dotted irregularly on the whole surface of slight concaved papilla. The protrusion with fine spinules was not found in the other pollen of C. Ma-Yuen and C. Lacryma-Jobi. But the protrusion was well-developed in the pollen of F_1 plant, 4x F_1 plant and 4x C. Ma-Yuen. The diameter of germ pore of 4x Coix pollen was larger as compared with that of 2x Coix pollen. As the results of these experiment it wes revealed generally that the similarity between the surface structure of pollen membrane of genus Coix and Zea was very closely

糯稲の類型化に関する考察(農学部門)

糯稲品種が, その胚乳澱粉粘度と玄米の緑化時水分含量を指標とする「糯性程度」(grade of glutinous nature)の差によつて分類されることを提案した。内・外国産26品種をこの方法によつて5つの類型に大別した。「糯性程度」の高い品種程, 一般に多蘗性で籾藁比率も高い。また「糯性程度」の最も高い品種は草丈や穂長が短く, 逆に最も低い品種は長稈, 長穂の傾向を示した。中間には, これらの形質について雑多な品種が混在している。日本及び朝鮮産品種あるいはA型品種群は, 比較的「糯性程度」の高いIII, IV, V型に属するものが多く, これに対して外国産あるいはB, C型品種は「糯性程度」と早晩性との間には明瞭な関係はないが, I型品種は例外なく晩生種である。糯稲にみられるこのような性質の相違は, 各種の生態的条件や民族の嗜好性による選抜の結果として分化したものと考えられる。(1) The authors tried to classify glutinous rice plants by their "grade of glutinous nature", using 26 varieties, 13 of Japan, 5 of China, 2 of Korea, 5 of Southeast Asia, 1 of Italy and 1 of South America (Table 1). Five grades such as I∿V were proposed by combining both starch viscosity of endosperm and water contents of grain at the time Ryokka happend, of which the most important properties in glutinous rice plant. From grade I to V, viscosity and water contents of grain became higher in each value as presented in Table 2 & Fig. 1. (2) Number of ears and ratio of grain to straw, in general, went hand in hand with the grade, showing larger values. Both culm and ear of varieties belonged the highest grade were shorter in length and vice versa in the case of varieties belonged the lowest one (Fig. 2). (3) Majority of varieties native to Japan and Korea, or A type grouped by MATSUO (1952), belonged to grade III, IV and V, while varieties distributed in Southeast Asia, or B and C types included large number of grade I and II. The correlation between the grade and date of heading was never recognizable, but it was found that varieties belonged grade I headed later with no exception (Fig. 3). (4) The differentiation of "grade of glutinous nature" in rice varieties as pointed above was thought to had been caused by selection of different environment and different taste of people

Coix 属の改良に関する育種学的研究 VII : Coix 属植物の X 線感受性および照射次代の雑種 F_2 の形質分離について(農学部門)

Coix属植物の栽培種であるハトムギと野生種のジュズダマ, およびその雑種F_1さらに人為的に作出した4xハトムギと4xF_1の5植物の乾燥種子に対して5∿20krのX線を照射し, 照射当代におけるX線感受性と, さらに照射F_1の次代における形質の分離および形質間の連関性に対するX線の作用を調査した。1.照射当代の発芽率および生存率は, 照射線量の増加にともない低下するが, 概してF_1は抵抗性を示し, 異質および同質四倍体はこれにつぎ, ハトムギおよびジュズダマは供試植物中最も感受性を示した。出穂期は, 両四倍体は線量増加にともないかなり遅延し, ハトムギおよびジュズダマはやや出穂促進の傾向を示したがF_1は殆ど影響されない。草丈は一般に線量とともに低下するが, F_1は5∿15krの線量では殆ど影響されない。花粉稔性はF_1および4xF_1では15krまでは殆ど低下せず, 20krにおいてかなり低下した。他の3種は線量増加にともない減少したが, 同質四倍体は花粉稔性については感受性が大である。種子稔性は線量とともに一次函数的に低下したが, F_1および四倍体は, ハトムギ, ジュズダマに比してその傾向は著しくない。2. F_1 (X_1)個体中の極早生個体によりF_2を育成したが, 早生選抜の効果はなく, 概して晩生個体を多く分離した。草丈の頻度分布はやや連続的となり, 線量とともに細茎を叢生する矮生個体がかなり出現した。生体重は高線量区でかなり増大する傾向を示した。花粉および種子稔性はいずれも低下し, とくに高線量区には低稔性個体の出現が多い。草丈と諸形質間の相関は, 対照区に比較してかなり低く, とくに分蘗数, 生体重および稔性などと草丈との間において著しく, 概してX線照射は遺伝子の多面発現ないしは連鎖に大きく影響することが推察された。3.本実験結果より, 雑種F_1はX線に対して最も抵抗性を示し, 異質および同質四倍体はこれにつぎ, ハトムギおよびジュズダマは最も感受性を示すことが明らかになつた。またX線照射を利用して雑種後代の育成を行なう場合には, 変異個体の選抜はもとより, とくに有用形質間の連関性を把握しつつ行なうことが必要であると考える。The present paper deals with the investigation on the radiosensitivity of several Coix varieties in the X_1 generation and the genic segregation in the F_2 generation raised from irradiated F_1 seeds. The Coix varieties used in this experiments were Hatomugi (Coix Ma-yuen ROMAN.), that is cultivated type in genus Coix, and Juzudama (Coix Lacryma-Jobi L.), that is wild type, and its F_1 hybrid, and two tetraploid varieties, namely autotetraploid Hatomugi and allotetraploid between Hatomugi and Juzudama. Dry dormant seeds of these varieties were irradiated with X-rays of 5-20kr. After treatments, these irradiated seeds were sown in the seed bed together with control respectively. Germination and survival rates decreased linearly according to the dosage. But the radiosensitivity on the germinating and survival ability of F_1 hybrid were lowest in all varieties and auto-and allotetraploids came after F_1 hybrid. Heading date of Hatomugi and Juzudama were early with the increase of dosage, in spite of two tetraploid were delayed. The plant height in each maturity of treated varieties inhibited with the higher doses of X-rays. The pollen fertility of the irradiated F_1 and 4xF_1 varieties showed no decline as compared with the control except the decrease of fertility in 20kr, but in the other varieties decreased linearly with the increase of dosage. As for the pollen and seed fertility of F_1 and 4xF_1 showed higher resistance than the other varieties. The earliest plants on heading date in irradiated F_1 plants were selected to grow F_2 progenies. In the F_2 (X_2) generation, the effect of selection on early heading in F_1 (X_1) plants was not recognized and the rate of late heading plants at higher doses of X-rays was much higher than in the control F_2 generation. The frequency distribution on plant height of F_2 (X_2) progenies showed continuous deviation whereas three types were segregated in the control F_2. In the F_2 (X_2) generation, the dwarf plants with many slender tillerings and the vigorous plants on the plant weight were observed at the heigher doses. As for the pollen fertility, the frequency of partially and completely sterile plants increased with dose rates. Asimilar tendency was observed in seed fertility. The phenotypical correlation were calculated chiefly between plant height and the other characters. In this result, correlation coefficients in X-irradiated F_2 were inferior to control F_2,especially low correlation was recognized between plant height and some characters namely number of tillering, plant weight, pollen and seed fertility as compared with the correlation between same characters in control F_2 plants. From these experimental results, it was concluded that the F_1 (Hatomugi×Juzudama) plants were the most resistant to radiation and auto- or allotetraploid Coix are resistant for only 2 or 3 characters and Hatomugi and Juzudama, that is the diploid species of Coix, had high sensitivity for many characters, on the other hand, it was conjectured from segregation of characters of F_2 plants to result from X-irradiated F_1 plants that the function of X-ray dose to character manifestation have effect sensitively upon the linkage or pleiotropism of genes

Coix 属の改良に関する育種学的研究 VIII : ハトムギ, ジュズダマおよび育成系統の刈取回数と青刈収量との関係(農学部門)

Coix属植物中の2種, ハトムギ(C.M.), ジュズダマ(C.L.)と, その雑種後代に育成した高桿系統F_4および倍数体の4xF_1の4種類の植物に対し刈取試験を行ない, 植物形態と生産力との関係について考察した。刈取は生育期間中に1∿4回実施したが, 各刈取区の最終刈はいずれも草丈の伸長停止期に行なつた。刈取後の再生枝の伸長速度には植物種類間にかなり明らかな差が認められ, 刈取頻度のいかんをとわずF_4は最も早く, かつ刈取を増すとともにF_4と他種の伸長差は大となる。4xF_1の草丈は, 初期の刈取ではC.L.より劣るが, 刈取頻度の増加とともに回復してC.L.をしのぐようになる。分蘗数はF_4が最も多く, 4xF_1は最も少ないが刈取頻度の増加にともない各作物とも急速に再生枝を分蘗し, 常に刈取前の分蘗をしのぐが, その状況はF_4とC.M.が特にすぐれ, C.M.および4xF_1との間に明らかな差異を示している。刈取直後の生体重は, 一般に各刈取区を通じてF_4が最も大である。4xF_1は1∿3回刈取区ではC.L.よりかなりすぐれるが, 後期の刈取区でやや劣つた。植物種類間および刈取頻度間には高い有意性を示した。以上の実験結果より, 供試植物中F_4は最も高い生産性を示し, 4xF_1,C.L.がこれにつぎはC.M.は最も劣ることが判明した。特にF_4は両親植物に比し, 各刈取区を通じて2倍以上の多収性を示した。一般に各植物とも年2回刈が最も多収であつた。他の刈取区では概して3回刈が良いが, 植物の種類により多少変異している。育成F_4系統に関しては2回刈が最も適当であり, 1回および3回刈もかなりすぐれている。4xF_1およびC.L.については2∿3回刈が適当であると思われる。The present paper deals with the investigation on the relation between cutting numbers and grass yields of some Coix varieties. The Coix varieties used in this study are Hatomugi (Coix Ma-yuen ROMAN., C. Lacryma-Jobi L. var. Ma-yuen STAPF. etc.), Juzudama (Coix Lacryma-Jobi L.), a strain in F_4 generation (Hatomugi × Juzudama), and 4xF_1 plants induced by colchicine treatment. In early growing stages of Coix plant, there are no remarkable difference in the growth of plant height of these Coix varieties. The difference of growth of plant height was recognized distinctly after the beginning of August. In this experiment the cuttings carried out from one to four times in growing stage of above Coix varieties. After the cutting of different cutting stages, the growth of plant height of F_4 strain was the most superior to that of the other varieties. With increase of cutting frequency, the number of tillerings increased rapidly compared with tillering before cutting and this tendency showed through four varieties especially F_4 strain and Juzudama resuscitated more tillerings than Hatomugi and 4xF_1. The grass weight of F_4 strain in cutting stages had the advantage over the other varieties, except in the third cutting of three cuttings. On the total grass yield of all cutting stages, F_4 strain showed high productivity that is about twice yield compared with that of parents. Generally speaking, the more useful number of cutting are two or three times in the growing stage of Coix varieties. From these experimental results, it was concluded that the F_4 strain was the most useful for soiling crops, especially we would be expected the heighest grass yield in the two times of cuttings. 4xF_1 and Juzudama are also useful varieties for soiling crops, if the sutable cutting stage in two or three cuttings are selected

Coix 属の改良に関する育種学的研究 XI : 栽植密度および混植によって生起する競合効果(農学部門)

Coix属植物は栽植条件の変化により, 形質の発現に変異を生ずることは, 従来より観察されているところである。したがって, ハトムギ, ジュズダマおよびF_5の育成優良系統に対して, 栽植距離を30cm, 60cmおよび90cmとして混植試験を行ない, 密度および混植による形質および収量の変異を追究した。1.生育期間中の草丈の伸長に関しては, 各供試植物とも密度効果が生育の比較的早い時期より現われ密植区ほど伸長速度が大きい。混植による競合は, ハトムギおよびジュズダマでは高稈個体による伸長促進が認められ, 密植区ほどその傾向は著しい。分けつ数の増加に対する密度効果は, 草丈に対するよりも顕著に現われ, 各供試植物とも生育の初期より密植区の分けつは抑制され, 疎植区の分けつ増加速度はきわめて大きい。また, 生育期間中に現われる混植の影響は, 供試植物の違いによって異なり, 一定の傾向を示さない。2.草丈, 分けつ数および乾物重の変異について分散分析を行なった結果, 両親植物の全形質とF_5系統の乾物重に, 密度区間に有意差が認められる。草丈は一般に密植とともに増大し, 分けつ数および乾物重は減少する。混植による競合生起の傾向は, 供試植物の違いとくに草丈の長短によって異なり, さらにこれは, 密度の大小によって著しく変化するため, 供試植物を通じて法則性を発見することはできないが, 概して両親植物の草丈は, 混植によって密植区で促進, 疎植区で抑制され, F_5系統はすべて混植によって抑制される傾向が認められる。分けつ数および乾物重においても, 各供試植物とも種々の変異が認められるが, 一定の傾向を示さない。概して両親植物は, 混植によって負, F_5系統は正の競合値を示す。3.各供試植物とも, 異なる密度区における草丈と, 個体の乾物重との間には負の相関が存在し, 分けつ数と乾物重との間には正の相関が認められるが, 密植区における個体数の増大によって, 単位面積当たりの総乾物収量は, 草丈の増大する密植区がすぐれ, 分けつ数の増加する疎植区がもっとも劣っている。4.以上の結果, 育成高稈系統の栽培にあたっては, かなり密植することによって, 生産性を向上させることができると考えられる。また, 異型個体と混植する場合には, 競合効果が植物の種類と栽植密度によって, かなり異なるので留意を要する。The present paper deals with the investigation on the competitive effect of some morphological characters of the genus Coix due to the change in environmental condition of culture. To investigate the non-genetical variation of characters of plants belonging to the genus Coix, the present writer cultured Hatomugi (Coix Ma-yuen Roman.), Juzudama (Coix Lacryma-Jobi L.) and F_5 strains bred with view to tallness in mix planting with three kinds of distance between each plant (30,60 and 90cm) and considered the variation of characters due to these conditions. Generally plant height, number of tillers and dry matter weight vary very much with the density of planting. That is to say, plant height increases considerably with dense planting while number of tillers and dry matter weight decreases remarkably. The variation of these characters due to density of planting changes its aspect again with mix planting and difference of kind of mixed plant have influence on the effect. Meanwhile the effect of mix planting is not so great as the effect of density. Interspecific difference of characters can not be clearly recognized in mix planting field, but generally speaking, short culm species are liable to be influenced by tall species. Though dry matter weight decreases by dense planting, harvest becomes larger as number of cultured plant increases remarkably. So the most effective method to high yield is to increase number of plant by means of comparatively dense planting. But before settling this matter, we must analyze the change of chemical composition of feed due to the change of characters and determine the best method of cultivation to enrich the com ponent useful as fodder crop

葯培養によるトウモロコシの半数体植物の育成 I : カルスの形成と根の分化について(農学部門)

トウモロコシの葯培養による半数体植物育成の可能性を検討するために, 1核期の花粉をふくむ葯を用いて, 変更Millerおよび変更Whiteの基本培地にauxinsならびにcytokininsを種々の割合に添加した培地に培養し, 培養初期における葯の形態的変化, カルス形成さらに器官分化の様相について追跡調査した。培養初期における葯形態の変化中, 変色枯死する葯はMiller培地で多く20∿40%である。逆に開裂葯はWhite培地で多く50∿64%に達し, 葯の肥大化はMiller培地上で10∿20%に達し, これらよりはいずれもカルス形成は認められない。培養後20日を経過した無変化の葯より, 後にカルス形成が認められる。カルス形成率は0.04%できわめて低い。カルスの形態は均一でなく, 肥大速度にも差異が認められるが概して緩慢である。カルスの移植培養によって根の分化が認められたが, 発根程度ならびにその速度は培養条件によって著しく影響されるが, 一般に伸長速度はおそい。半数性カルスならびに根の存在を確認することが出来ず, また茎葉分化が認められなかったが, 本実験の結果, トウモロコシのカルス形成ならびに根の分化は可能であり, 半数体植物育成の可能性を類推させた。This experiment was made a trial for investigate possibility on induction of haploid plant by anther culture in maize (Zea mays L.). Several anthers with uni-nucleate stage of pollen from male flowers, 7∿10 days before heading, were placed on the medium. The basic media were prepared modified Whites medium and modified Miller\u27s medium containing various concentration of 2,4-D, IAA and kinetin. The media were adjusted to pH5.8. Among the morphological variation of anthers placed on the media, anthers changed brown and died after a while were amounted about 20∿40% of all placed ones on Miller\u27s media, and dehiscent anthers and enlarged ones were observed 50∿64% on White\u27s media and 10∿20% on Miller\u27s media respectively. Primordium of callus was formed in the ends of anthers inchanged in about 20 days after anther culture, and decided callus formation was recognized in extremely few anthers in 4∿8 weeks after anther placing. The percentage of callus formation was about 0.04%. The callus formed by anther culture had not uniformity in the size and colour, and generally the state of callus increased was very inactivity. Callus formed on several media were transplanted on modified Miller\u27s media in supplement with various auxins and kinetin. Degree of rooting from callus and it\u27s velocity of growth were susceptible to influences from the conditions of media. In general, state of rooting was very inactivity on all media and the optimum constituents of media for root differentiation were yet to be determined through result of above experiments. Roots with haploid number of chromosomes were well not ascertained and the differentiation of leaves and stem from callus were not recognized to the last of these anther culture. From these investigation mentioned above, it was recognized that it is difficult to make the haploid plant of maize by anther culture. Our experimental results show, however, that the callus formation and root differentiation from callus were successful. We expect to establish, therefore, available method for induction of haploid maize by improving the method of anther culture

作物の形質発現の変動性よりみた収量安定性に関する研究 II : 水稲諸形質の変動性に対する環境要因の効果について(農学部門)

環境条件の変化に伴う作物の形質の変動性の変異を解析するために, 水稲10品種を3密度, 2作期, 2年次の計12環境条件下で栽培し, 諸形質の個体内変動量(内CV), 個体間変動量(間CV)およびそれぞれの環境間変動量(ECV)の相互関係について考察した。1)内, 間両CVの形質間差異はきわめて大きいが, 各々のECVはいずれの形質においてもほぼ近似した値を示し, 環境変化による両変動性の変異にはほとんど形質間差異が認められない。2)内CVはいずれの形質においても間CVよりも大きいが, そのECVにおいては逆に内CVの方が小さく, さらに分散分析の結果によっても, 内CVに有意性を示す環境要因はほとんど存在しないが, 間CVにおいてはいずれの環境要因もほぼ全形質にわたって有意性を示し, 変動性に対する環境変化の影響は個体内においてよりも個体間において大きく, 両変動性はかなり異なった反応を示している。3)一般に, 形質値と内CV各々のECV間には負の相関を示す傾向が認められ, 形質発現力の環境間変異が大きい品種ほど, 環境変化によるその個体内変動性の変異は小さい。しかし, 内CVと間CV各々のECV間には一定の関係は認められず, 品種別に検討しても, 全形質にわたって特徴のある反応を示す品種は認められない。Variations of variabilities of several characters in rice varieties were studied in relation to difference in environmental conditions. Ten rice varieties were cultured under 12 environments, and the interrelationship among the variabilities which occurred within a plant (Within CV), among plants (Between CV) and the variations of the respective variabilities in environments (ECV) were examined. As for the degrees of variations of Within CV and Between CV, little difference in characters was recognized, although the large difference was detected in both the CV per se. The Within CV was larger than the Between CV in all characters examined. On the other hand, the reverse tendency was shown between the respective ECV. The influence of environmental change was, therefor, larger to the variablilities which occurred among plants than to those within a plant. Negative correlations were shown between both ECV of character values and Within CV, but not clear relation between both ECV of Within CV and Between CV. From these results, it is concluded that both the variabilities which occurred within a plant and among plants respond to the change in environmental conditions by fairly different mechanisms

Coix 属の改良に関する育種学的研究 XIV : 育成系統の直播栽培における生産性について(農学部門)

Coix属の育成系統に対する直播適応性を検討した。1)直播区の種子発芽は, 室内播種に比べて発芽開始が約10日遅れるが, 90%以上の高い発芽率を示した。2)草丈の伸長速度は, 直播の時期にかかわらず密植区は生育初期に, 疎植区は生育中期以降に大である。移植区もほぼ同様の傾向を示すが, 移植時の生育障害により成熟期にはかなり直播より劣る。3)分けつ数の増加に対しては, 直播の疎植は密植に比べて分けつ期間が長く, 初期の分けつ増加量も大きい。移植区も疎植により分けつは増大するが, 移植時の分けつ停止の影響が大きい。4)乳熟期における草丈, 分けつ数, 生体重, 乾物重などは, 直播は移植に比し, 疎植は密植に比し大である。形質の変動量は概して直播が小さく, 移植ではとくに密植により変異が増大する。点播粒数については分けつ数, 生体重でやや多粒播種がすぐれる傾向を示す。5)草丈および分けつ数と個体生体重との間には, とくに密植区にそれぞれ正の有意相関が認められる。6)個体当たりの生体重は, 一般に直播, 疎植かつ多粒点播区がすぐれるが, 単位面積当たりの生草収量は, 直播の密植区が著しく大である。7)以上の結果Coix属育成系統の直播適応性はきわめて高く, とくに生育初期∿中期の青刈利用では, 密播かつ多粒点播が望ましいと考えられる。The present paper deals with the investigation on the adaptability test in direct sowing culture of improved variety of genus Coix. In the experiment, the growing process were investigated by means of planting in different seeding time, planting density and number of sowing seed in direct sowing comparing with those in the transplanting and analysis of several characters were culculated statistically in milk-ripe stage. The experimental result can be summarized as follows : 1. The sowing seed showed high germination percentage as above 90%, but the biginning of germination was delayed about 10 days compard with sowing in the glass house. 2. At the earlier growing season, in direct sowing and transplanting plots plant height in the densely sown plots was higher than that in the sparsely sown plots, but vice versa after that time. At the date of maturity, the plant height in transplanting inferior to that in direct sowing. 3. At the earlier growing season, the number of tiller per individual plant in the sparsely sown plot of direct sowing showed an incresed over that in the densely plot. But in the transplanting above tendency was ricognized at later growing season. 4. The mean value and coefficient of variation of plant height, number of tiller, plant weight and dry matter weight were calculated in the milkripe stage. These statistical values in direct sowing plots were larger than those in transplanting plots. It may be laid down as a general rule that the variates between plant of those characters in direct sowing were smaller than those in transplanting, especially, in transplanting the variates in densely plot showed an increased over that in sparsely plot. 5. In the experimental conditions en bloc, the high correlation between plant height and plant weight was recognized in densely sown plot, in the same way between number of tiller and plant weight. 6. In the sparsely sown and three sowing seed plot of direct sowing, the plant weight per individual plant showed maximum value, but on the yield (plant weight) per unit area, that in the densely sown plot of direct sowing was superior to that in other experimental condition. From these investigation mentioned above, it will be concluded that the improved variety of genus Coix are very adaptable as forage crop in direct sowing culture