Diter wettstein (31 risultati)
- Rilegato
Da: Wissenschaftliches Antiquariat Köln Dr. Sebastian Peters UG, Köln, GermaniaWissenschaftliches Antiquariat Köln Dr. Sebastian Peters UG
Contatta il venditoreVenditore con 5 stelleCondizione: Usato - Molto buono
EUR 35,00
EUR 10,00 spedizioneSpedito da Germania a U.S.A.Quantità: 1 disponibili
Condizione: gut. IX, 697 S., Abb., 24 cm, Bibliotheksexemplar. Sprache: Englisch.
Lingua: Tedesco
Editore: Stuttgart, Gustav Fischer Verlag,, 1958
Da: Antiquariat am Ungererbad-Wilfrid Robin, München, GermaniaAntiquariat am Ungererbad-Wilfrid Robin
Contatta il venditoreVenditore con 5 stelleCondizione: Usato - Molto buono
EUR 6,50
EUR 22,50 spedizioneSpedito da Germania a U.S.A.Quantità: 1 disponibili
Condizione: Gut. Erstauflage. Bll. + 303 S. mit Anhang (Verz. d. Fachausdrücke, Schrifttum u. Register) u. mit 194 (s/w.) Abbildungen im Text (Fotos u. Graphiken). Papier Zeitbedingt minimal randgebräunt aber sauber. * Autoren waren damals Professor und Dozent an der Universität Stockholm, Schweden. Sprache: Deutsch Gewicht in G…ramm: 750 Gr.-8°, O(Grün)-GanzLnw. mit Goldgepr.-Titelung u. (Orange)Umschlag (Umschlag mit e. kl. Läsur an ober.-Kapital die hinterlegt wurde). Gut erhalten.
Mutationsforschung und Züchtung; Mutationsauslösung durch ionisierende Strahlung
Wettstein, Diter von; Gustafsson, Ake; Ehrenberg, Lars; Straub, Josef
Editore: Westdeutscher Verlag, Köln - Opladen, 1957
- Brossura
Da: Versandantiquariat BUCHvk, Gunzenhausen, GermaniaVersandantiquariat BUCHvk
Contatta il venditoreVenditore con 5 stelleCondizione: Usato - Ottimo
EUR 10,00
EUR 70,00 spedizioneSpedito da Germania a U.S.A.Quantità: 1 disponibili
Softcover. Condizione: Sehr gut. 90 S., Broschur, 24 cm, sehr guter Zustand. Buch.
Mutationsforschung und Züchtung / Mutationsauslösung durch ionisierende Strahlen (Arbeitsgemeinschaft für Forschung des Landes Nordrhein-Westfalen, 73) (German Edition)
Von Wettstein, Diter; Gustafsson, Åke; Ehrenberg, Lars; Straub, Josef
- Brossura
Da: Ria Christie Collections, Uxbridge, Regno UnitoRia Christie Collections
Contatta il venditoreVenditore con 5 stelleCondizione: Nuovo
EUR 60,83
EUR 14,05 spedizioneSpedito da Regno Unito a U.S.A.Quantità: Più di 20 disponibili
Condizione: New. In.
- Brossura
Da: Books Puddle, New York, NY, U.S.A.Books Puddle
Contatta il venditoreVenditore con 4 stelleCondizione: Nuovo
EUR 78,96
EUR 3,49 spedizioneSpedito in U.S.A.Quantità: 4 disponibili
Condizione: New. pp. 92.
Lingua: Inglese
Editore: Acta Agriculturae Scandinavica, Vol. IV, No. III, 1954, 1954
Da: Robinson Street Books, IOBA, Binghamton, NY, U.S.A.Robinson Street Books, IOBA
Contatta il venditoreVenditore con 4 stelleMembro dell’associazione: IOBA
Condizione: Usato - Molto buono
EUR 175,81
EUR 8,32 spedizioneSpedito in U.S.A.Quantità: 1 disponibili
Pamphlet. Condizione: Collectible; Very Good. Prompt Shipment, shipped in Boxes, Tracking PROVIDEDOffprint. Very good condition. First edition. Offprint. Original wrappers. Science. Botany. Rust stains on paper from staples.*.
Lingua: Inglese
Editore: Pergamon Press, 1963, 1963
Da: Robinson Street Books, IOBA, Binghamton, NY, U.S.A.Robinson Street Books, IOBA
Contatta il venditoreVenditore con 4 stelleMembro dell’associazione: IOBA
Condizione: Usato - Molto buono
EUR 175,81
EUR 8,32 spedizioneSpedito in U.S.A.Quantità: 1 disponibili
Pamphlet. Condizione: Collectible; Very Good. Prompt Shipment, shipped in Boxes, Tracking PROVIDEDOffprint. Very good condition. First edition. Offprint. Original wrappers. Genetics Today, Proceedings of the XI International Congress of Genetics, The Hague, The Netherlands, September 1963, pp. 591-612. Science. Genetics. Botany.… Staples are rusted.*.
Genetic Regulation of Chlorophyll Synthesis Analyzed with Mutants in Barley by Von Wettstein, Diter; Kahn, Albert; Nielson, Ole F.; and Gough, Simon
Von Wettstein, Diter; Kahn, Albert; Nielson, Ole F.; and Gough, Simon
Lingua: Inglese
Editore: The American Association for the Advancement of Science, 1974, 1974
Da: Robinson Street Books, IOBA, Binghamton, NY, U.S.A.Robinson Street Books, IOBA
Contatta il venditoreVenditore con 4 stelleMembro dell’associazione: IOBA
Condizione: Usato - Molto buono
EUR 175,81
EUR 8,32 spedizioneSpedito in U.S.A.Quantità: 1 disponibili
Pamphlet. Condizione: Collectible; Very Good. Prompt Shipment, shipped in Boxes, Tracking PROVIDEDOffprint. Very good condition. First edition. Offprint. Original wrappers. Ownership stamp of Arnold H. Sparrow on front cover. Science, Vol. 184, pp. 800-802, May 17, 1974. Science. Botany. Genetics. *.
Lingua: Inglese
Editore: Separat ur Hereditas, vol. 43, pp. 298-302, 1957, 1957
Da: Robinson Street Books, IOBA, Binghamton, NY, U.S.A.Robinson Street Books, IOBA
Contatta il venditoreVenditore con 4 stelleMembro dell’associazione: IOBA
Condizione: Usato - Molto buono
EUR 175,81
EUR 8,32 spedizioneSpedito in U.S.A.Quantità: 1 disponibili
Pamphlet. Condizione: Collectible; Very Good. Prompt Shipment, shipped in Boxes, Tracking PROVIDEDOffprint. Very good condition. First edition. Offprint. Original wrappers. Ownership stamp of A.H. Sparrow on front cover. Science. Botany. Staples are rusted.*.
Lingua: Inglese
Editore: Pergamon Press, 1964, 1964
Da: Robinson Street Books, IOBA, Binghamton, NY, U.S.A.Robinson Street Books, IOBA
Contatta il venditoreVenditore con 4 stelleMembro dell’associazione: IOBA
Condizione: Usato - Molto buono
EUR 175,81
EUR 8,32 spedizioneSpedito in U.S.A.Quantità: 1 disponibili
Pamphlet. Condizione: Collectible; Very Good. Prompt Shipment, shipped in Boxes, Tracking PROVIDEDOffprint. Very good condition. First edition. Offprint. Original wrappers. Ownership stamp of Arnold H. Sparrow on title page. Genetics Today, Proceedings of the XI International Congress of Genetics, The Hague, The Netherlands, Sep…tember 1963, pp. 591-612. Science. Genetics. Botany. Staples are rusted.*.
Lingua: Inglese
Editore: Separat ur Hereditas, Vol. 43, pp. 303-317, 1957, 1957
Da: Robinson Street Books, IOBA, Binghamton, NY, U.S.A.Robinson Street Books, IOBA
Contatta il venditoreVenditore con 4 stelleMembro dell’associazione: IOBA
Condizione: Usato - Molto buono
EUR 175,81
EUR 8,32 spedizioneSpedito in U.S.A.Quantità: 1 disponibili
Pamphlet. Condizione: Collectible; Very Good. Prompt Shipment, shipped in Boxes, Tracking PROVIDEDOffprint. Very good condition. First edition. Offprint. Original wrappers. Ownership stamp of Thomas W. Whitaker on front cover. Science. Genetics. Biology. Staples are rusted.*.
Lingua: Inglese
Editore: Verlag der Zeitschrift fur Naturforschung, Tubingen, 1962, 1962
Da: Robinson Street Books, IOBA, Binghamton, NY, U.S.A.Robinson Street Books, IOBA
Contatta il venditoreVenditore con 4 stelleMembro dell’associazione: IOBA
Condizione: Usato - Molto buono
EUR 175,81
EUR 8,32 spedizioneSpedito in U.S.A.Quantità: 1 disponibili
Pamphlet. Condizione: Collectible; Very Good. Prompt Shipment, shipped in Boxes, Tracking PROVIDEDOffprint. Very good condition. First edition. Offprint. Original wrappers. Ownership stamp of Arnold H. Sparrow on front cover. Zeitschrift fur Naturforschung, Vol. 17 b, No. 6, 1962. Science. Biology.*.
Lingua: Inglese
Editore: Separat ur Hereditas, Vol. 43, pp. 303-317, 1957, 1957
Da: Robinson Street Books, IOBA, Binghamton, NY, U.S.A.Robinson Street Books, IOBA
Contatta il venditoreVenditore con 4 stelleMembro dell’associazione: IOBA
Condizione: Usato - Molto buono
EUR 175,81
EUR 8,32 spedizioneSpedito in U.S.A.Quantità: 1 disponibili
Pamphlet. Condizione: Collectible; Very Good. Prompt Shipment, shipped in Boxes, Tracking PROVIDEDOffprint. Very good condition. First edition. Offprint. Original wrappers. Ownership stamp of A.H. Sparrow on front cover. Science. Genetics. Staples are rusted.*.
Mutationsforschung Und Zuchtung / Mutationsauslosung Durch Ionisierende Strahlen
Von Wettstein, Diter; Gustafsson, Ake; Ehrenberg, Lars; Straub, Josef
- Brossura
Da: Kennys Bookshop and Art Galleries Ltd., Galway, GY, IrlandaKennys Bookshop and Art Galleries Ltd.
Contatta il venditoreVenditore con 5 stelleCondizione: Nuovo
EUR 72,65
EUR 10,50 spedizioneSpedito da Irlanda a U.S.A.Quantità: 15 disponibili
Condizione: New. Series: Arbeitsgemeinschaft Fur Forschung Des Landes Nordrhein-Westf. Num Pages: black & white illustrations, colour illustrations, bibliography. BIC Classification: GB; PD. Category: (G) General (US: Trade). Dimension: 244 x 170 x 5. Weight in Grams: 159. . 1959. Paperback / so. . . . .
Editore: Westdt. Verl., 1959
Da: AHA-BUCH GmbH, Einbeck, GermaniaAHA-BUCH GmbH
Contatta il venditoreVenditore con 5 stelleCondizione: Usato - Ottimo
EUR 7,87
EUR 65,00 spedizioneSpedito da Germania a U.S.A.Quantità: 1 disponibili
Condizione: Sehr gut. Gebraucht - Sehr gut Sofortversand, mit Schutzumschlag,uebliche Markierungsstempel/Zeichen, altersgemaesser SEHR GUTER Zustand.
Mutationsforschung Und Züchtung / Mutationsauslösung Durch Ionisierende Strahlen
Von Wettstein, Diter/ Gustafsson, Åke/ Ehrenberg, Lars/ Straub, Josef
- Brossura
Da: Revaluation Books, Exeter, Regno UnitoRevaluation Books
Contatta il venditoreVenditore con 5 stelleCondizione: Nuovo
EUR 83,77
EUR 11,73 spedizioneSpedito da Regno Unito a U.S.A.Quantità: 2 disponibili
Paperback. Condizione: Brand New. 90 pages. German language. 9.60x6.69x0.22 inches. In Stock.
Mutationsforschung Und Zuchtung / Mutationsauslosung Durch Ionisierende Strahlen
Von Wettstein, Diter; Gustafsson, Ake; Ehrenberg, Lars; Straub, Josef
- Brossura
Da: Kennys Bookstore, Olney, MD, U.S.A.Kennys Bookstore
Contatta il venditoreVenditore con 5 stelleCondizione: Nuovo
EUR 91,39
EUR 9,19 spedizioneSpedito in U.S.A.Quantità: 15 disponibili
Condizione: New. Series: Arbeitsgemeinschaft Fur Forschung Des Landes Nordrhein-Westf. Num Pages: black & white illustrations, colour illustrations, bibliography. BIC Classification: GB; PD. Category: (G) General (US: Trade). Dimension: 244 x 170 x 5. Weight in Grams: 159. . 1959. Paperback / so. . . . . Books ship from the US a…nd Ireland.
Editore: Kopenhagen, 22. August 1978., 1978
- Brossura
- Manoscritto
Da: Kotte Autographs GmbH, Roßhaupten, GermaniaKotte Autographs GmbH
Contatta il venditoreVenditore con 5 stelleCondizione: Usato
EUR 190,00
EUR 20,00 spedizioneSpedito da Germania a U.S.A.Quantità: 1 disponibili
1½ SS. auf 2 Bll. Gr.-4to. Mit einigen Beilagen (s. u.). An den Genetiker und Molekularbiologen Hans Ferdinand Linskens (19212007), dem er eine deutschsprachige Übersetzung von vier kleinen Mitteilungen über Carl von Linné aus der Tidningar ufgifne i Upsala" übersendet. Diter von Wettstein ist R. A. Nilan Distinguished Professor… am Department of Crop and Soil Sciences & School of Molecular Biosciences an der Washington State University. Auf Briefpapier mit gedr. Briefkopf. Beiliegend 14 Bll. der genannten Zeitschrift, ein Exemplar von C. A. Oudemans' Rede ter herdenking van den sterfdag van Carolus Linnaeus, eene eeuw na diens verscheiden" (Amsterdam, Scheltema & Holkema, 1878; 40 SS., bedruckte Originalbroschur, 4to) sowie 7 Bll. Zeitungsausschnitte u. a.
Genetic Regulation of Chlorophyll Synthesis Analyzed with Mutants in Barley
Diter Von Wettstein, Albert Kahn, Ole F. Nielsen and Simon Gough
Editore: Reprinted from 17 May 1974, volume 184 pp. 800-802, 1974
Da: Robinson Street Books, IOBA, Binghamton, NY, U.S.A.Robinson Street Books, IOBA
Contatta il venditoreVenditore con 4 stelleMembro dell’associazione: IOBA
Condizione: Usato - Discreto
EUR 175,81
EUR 8,32 spedizioneSpedito in U.S.A.Quantità: 1 disponibili
Pamphlet. Condizione: Acceptable. Prompt Shipment, shipped in Boxes, Tracking PROVIDEDOffprint. Pamphlet, previous owner underlined author, Reprinted from 17 May 1974, volume 184 pp. 800-802.
Editore: From DEVELOPMENTAL CYTOLOGY edited by Dorothea Rudnick Copyright, 1959, by th RONALD PRESS COMPANY, 1959
Da: Robinson Street Books, IOBA, Binghamton, NY, U.S.A.Robinson Street Books, IOBA
Contatta il venditoreVenditore con 4 stelleMembro dell’associazione: IOBA
Condizione: Usato - Buono
EUR 175,81
EUR 8,32 spedizioneSpedito in U.S.A.Quantità: 1 disponibili
Pamphlet. Condizione: Good. Prompt Shipment, shipped in Boxes, Tracking PROVIDEDOffprint. Staple binding, previous owner stamped upper right hand side, From DEVELOPMENTAL CYTOLOGY edited by Dorothea Rudnick Copyright, 1959, by th RONALD PRESS COMPANY.
Editore: Reprinted from THE PHOTOCHEMICAL APPARATUS ITS STRUCTURE AND FUNCTION BROOKHAVEN SYMPOSIA IN BIOLOGY: No. 11 (1958), 1958
Da: Robinson Street Books, IOBA, Binghamton, NY, U.S.A.Robinson Street Books, IOBA
Contatta il venditoreVenditore con 4 stelleMembro dell’associazione: IOBA
Condizione: Usato - Buono
EUR 175,81
EUR 8,32 spedizioneSpedito in U.S.A.Quantità: 1 disponibili
Pamphlet. Condizione: Good. Prompt Shipment, shipped in Boxes, Tracking PROVIDEDOffprint. Staple binding, previous owner wrote on upper rigth hand side, Reprinted from THE PHOTOCHEMICAL APPARATUS ITS STRUCTURE AND FUNCTION BROOKHAVEN SYMPOSIA IN BIOLOGY: No. 11 (1958).
Editore: Hereditas 46:700-708 (1960), 1960
Da: Robinson Street Books, IOBA, Binghamton, NY, U.S.A.Robinson Street Books, IOBA
Contatta il venditoreVenditore con 4 stelleMembro dell’associazione: IOBA
Condizione: Usato - Buono
EUR 175,81
EUR 8,32 spedizioneSpedito in U.S.A.Quantità: 1 disponibili
Pamphlet. Condizione: Good. Prompt Shipment, shipped in Boxes, Tracking PROVIDEDOffprint. Staple binding, previous owner marked upper right hand side, Hereditas 46:700-708 (1960).
Editore: Canadian Journal of Botany, Vol. 39, 1961, 1961
Da: Robinson Street Books, IOBA, Binghamton, NY, U.S.A.Robinson Street Books, IOBA
Contatta il venditoreVenditore con 4 stelleMembro dell’associazione: IOBA
Condizione: Usato - Buono
EUR 175,81
EUR 8,32 spedizioneSpedito in U.S.A.Quantità: 1 disponibili
Pamphlet. Condizione: Good. Prompt Shipment, shipped in Boxes, Tracking PROVIDEDOffprint. Staple binding, previous owner marked upper right and left of cover page, Canadian Journal of Botany, Vol. 39, 1961.
Editore: Meist Kopenhagen, 1978 bis 1994., 1994
- Manoscritto
Da: Kotte Autographs GmbH, Roßhaupten, GermaniaKotte Autographs GmbH
Contatta il venditoreVenditore con 5 stelleCondizione: Usato
EUR 160,00
EUR 20,00 spedizioneSpedito da Germania a U.S.A.Quantità: 1 disponibili
Zusammen 5 SS. auf 6 Bll. Gr.-4to und (qu.-)8vo. Mit einer Beilage. An den Genetiker und Molekularbiologen Hans Ferdinand Linskens (19212007) mit Wünschen zu Weihnachten, betr. des Tagebuchs seines Vaters und zur Übersendung von Separatdrucken. Diter von Wettstein ist R. A. Nilan Distinguished Professor am Department of Crop and… Soil Sciences & School of Molecular Biosciences an der Washington State University. Beiliegend ein e. Brief von Wettsteins Mutter sowie ein S/W-Portrait seines Vater, des Botanikers und Direktors des Kaiser Wilhelm Instituts für Biologie Fritz von Wettstein (18951945; 179:136 mm).
- Brossura
- Print on Demand
Da: BuchWeltWeit Ludwig Meier e.K., Bergisch Gladbach, GermaniaBuchWeltWeit Ludwig Meier e.K.
Contatta il venditoreVenditore con 5 stelleCondizione: Nuovo
EUR 54,99
EUR 23,00 spedizioneSpedito da Germania a U.S.A.Quantità: 2 disponibili
Taschenbuch. Condizione: Neu. This item is printed on demand - it takes 3-4 days longer - Neuware -Applying ionizing radiations and chemical mutagens we are now in a better condition of regulating and predicting the change of cultivated species into organisms improved from an agricultural point of view. Either this takes place b…y mutation alone or by mutation as an addendum to hybridization and polyploidy. Irradiation can produce genotypes which Nature does not seem to have figured. Some induced chromosome changes, at least, have not yet been found in nature. Ionizing radiations, administered either in a chronical or acute manner, cause both gene mutations and chromosomal rearrangements. Depending on the physiological stage and the genetical constitution of the irradiated material, as well as on the selection technique involved, the mutation process can be changed qualitatively and quantitatively to a considerable extent. Applying chemical mutagens such as 8-ethoxycoffeine, nebularine or myleran we can differentiate between gene-mutations and chromosomal rearrangements. Chromosome breakage can be concentrated to heterochromatic regions or special structures of the chromosomes. Under the combined influence of ionizing radiations and chemical mutagens he terochromatic and euchromatic breaks may be reunited in a fashion scarcely visualized before. With ethylene oxide and ethylene imine the frequency of factor-mutations - also viable and highly productive ones - can be increased 2-3 times above the highest mutation level achieved with ionizing radia tions. Considerable specificity is found in the mutability and the mecha nism of mutation in individual loci of barley depending on the ion density of the radiations used. 90 pp. Deutsch.
- Brossura
- Print on Demand
Da: Majestic Books, Hounslow, Regno UnitoMajestic Books
Contatta il venditoreVenditore con 4 stelleCondizione: Nuovo
EUR 80,08
EUR 7,62 spedizioneSpedito da Regno Unito a U.S.A.Quantità: 4 disponibili
Condizione: New. Print on Demand pp. 92.
- Brossura
- Print on Demand
Da: Biblios, frankfurt am main, HESSE, GermaniaBiblios
Contatta il venditoreVenditore con 4 stelleCondizione: Nuovo
EUR 80,55
EUR 9,95 spedizioneSpedito da Germania a U.S.A.Quantità: 4 disponibili
Condizione: New. PRINT ON DEMAND pp. 92.
Mutationsforschung und Züchtung / Mutationsausloesung durch ionisierende Strahlen
Diter von Wettstein|Åke Gustafsson|Lars Ehrenberg|Josef Straub
- Brossura
- Print on Demand
Da: moluna, Greven, Germaniamoluna
Contatta il venditoreVenditore con 5 stelleCondizione: Nuovo
EUR 54,99
EUR 48,99 spedizioneSpedito da Germania a U.S.A.Quantità: Più di 20 disponibili
Condizione: New. Dieser Artikel ist ein Print on Demand Artikel und wird nach Ihrer Bestellung fuer Sie gedruckt. Mutationsforschung und Zuechtung.- Mutationsausloesung durch ionisierende Strahlung.Applying ionizing radiations and chemical mutagens we are now in a better condition of regulating and predicting the change of culti…vated species into organisms improved f.
Lingua: Tedesco
Editore: VS Verlag Für Sozialwissenschaften, VS Verlag Für Sozialwissenschaften Jan 1959, 1959
- Brossura
- Print on Demand
Da: buchversandmimpf2000, Emtmannsberg, BAYE, Germaniabuchversandmimpf2000
Contatta il venditoreVenditore con 5 stelleCondizione: Nuovo
EUR 54,99
EUR 60,00 spedizioneSpedito da Germania a U.S.A.Quantità: 1 disponibili
Taschenbuch. Condizione: Neu. This item is printed on demand - Print on Demand Titel. Neuware -Applying ionizing radiations and chemical mutagens we are now in a better condition of regulating and predicting the change of cultivated species into organisms improved from an agricultural point of view. Either this takes place by mu…tation alone or by mutation as an addendum to hybridization and polyploidy. Irradiation can produce genotypes which Nature does not seem to have figured. Some induced chromosome changes, at least, have not yet been found in nature. Ionizing radiations, administered either in a chronical or acute manner, cause both gene mutations and chromosomal rearrangements. Depending on the physiological stage and the genetical constitution of the irradiated material, as well as on the selection technique involved, the mutation process can be changed qualitatively and quantitatively to a considerable extent. Applying chemical mutagens such as 8-ethoxycoffeine, nebularine or myleran we can differentiate between gene-mutations and chromosomal rearrangements. Chromosome breakage can be concentrated to heterochromatic regions or special structures of the chromosomes. Under the combined influence of ionizing radiations and chemical mutagens he terochromatic and euchromatic breaks may be reunited in a fashion scarcely visualized before. With ethylene oxide and ethylene imine the frequency of factor-mutations - also viable and highly productive ones - can be increased 2-3 times above the highest mutation level achieved with ionizing radia tions. Considerable specificity is found in the mutability and the mecha nism of mutation in individual loci of barley depending on the ion density of the radiations used.Springer VS in Springer Science + Business Media, Abraham-Lincoln-Straße 46, 65189 Wiesbaden 92 pp. Deutsch.
Lingua: Tedesco
Editore: VS Verlag Für Sozialwissenschaften, VS Verlag Für Sozialwissenschaften, 1959
- Brossura
- Print on Demand
Da: AHA-BUCH GmbH, Einbeck, GermaniaAHA-BUCH GmbH
Contatta il venditoreVenditore con 5 stelleCondizione: Nuovo
EUR 54,99
EUR 60,88 spedizioneSpedito da Germania a U.S.A.Quantità: 1 disponibili
Taschenbuch. Condizione: Neu. nach der Bestellung gedruckt Neuware - Printed after ordering - Applying ionizing radiations and chemical mutagens we are now in a better condition of regulating and predicting the change of cultivated species into organisms improved from an agricultural point of view. Either this takes place by mut…ation alone or by mutation as an addendum to hybridization and polyploidy. Irradiation can produce genotypes which Nature does not seem to have figured. Some induced chromosome changes, at least, have not yet been found in nature. Ionizing radiations, administered either in a chronical or acute manner, cause both gene mutations and chromosomal rearrangements. Depending on the physiological stage and the genetical constitution of the irradiated material, as well as on the selection technique involved, the mutation process can be changed qualitatively and quantitatively to a considerable extent. Applying chemical mutagens such as 8-ethoxycoffeine, nebularine or myleran we can differentiate between gene-mutations and chromosomal rearrangements. Chromosome breakage can be concentrated to heterochromatic regions or special structures of the chromosomes. Under the combined influence of ionizing radiations and chemical mutagens he terochromatic and euchromatic breaks may be reunited in a fashion scarcely visualized before. With ethylene oxide and ethylene imine the frequency of factor-mutations - also viable and highly productive ones - can be increased 2-3 times above the highest mutation level achieved with ionizing radia tions. Considerable specificity is found in the mutability and the mecha nism of mutation in individual loci of barley depending on the ion density of the radiations used.
