[The chiral mutagens: cytogenetic effects on higher plants].

The paper covers investigation of cytogenetic activity of chiral mutagens and their specific effects on the plant cells chromosomes of soft winter wheat (Triticum aestivum L.). Comparative analysis of cytogenetic activity of chiral NEU: S(+)1-N-nitroso- 1-N-methyl-3-N-sec-buthylureas (S(+)NMsBU) and R(-)1-N-nitroso- 1N-methyl-3-Nsec-buthylureas (R(-)NMsBU) on winter wheat was performed. As it was shown by the frequency of chromosomal aberrations the S(+) stereoisomer was twice more active than R(-). In addition to typical anaphase aberrations (fragments, bridges, lagging chromosomes) the numerous mitosis pathologies were revealed - K-mitoses, hyperspiralization and despiralization of chromosomes, unequal allocation of chromosomes between the daughter nuclei, mass fragmentation, nondisjunction and chromosome adhesion, three-pole mitoses, etc. Neither of the mentioned pathologies was observed under the action of NEU and gamma-rays.

[A comparative analysis of plant hereditary variability during mutagenic treatment of the generative cells and seeds of corn]. / Sravnitel'nyi analiz nasledstvennoi izmenchivosti rastenii pri mutagennoi obrabotke generativnykh kletok i semian kukuruzy.

The effect of mutagenic factors on maize generative cells during different gametogenesis stages, as well as on mature pollen and gametes causes an essential raise in frequency, widening in visible mutation spectra and seems to be more efficient than on dry seeds. Original mutations on qualitative and quantitative characters have been obtained.

[Mutagenic effect of the herbicide Titus in maize]. / Mutagennii ieffekt gerbitsida Titusa u kukuruz'i.

Mutagenic effect of the new herbicide titus has been studied by the tests of chromosome aberration and gene mutations in maize. It has been shown that the preparation in question possesses a definite mutagenic activity, which sometimes 5-7 times exceeded the level of spontaneous mutating. Therefore, when recommending it for application in agriculture it is necessary strict following recommended doses, because even slight excess may result in considerable genetic consequences. It is also of great importance to apply this herbicide during the recommended stage. The application of titus for maize in hybridization plots as well as in nurseries for reproduction of elite and super elite lines is not recommended.

[Mutagenic activity of nitrosoalkylureas and diazoketones on corn. I]. / Izuchenie mutagennoi aktivnosti nitrozoalkilmochevin i diazoketonov na kukuruze. Soobshchenie I.

Among the nitrozoalkylureas studied, nitrozoethylurea proved to be the most effective in respect to the frequency of induced chromosome aberrations. Diazoketones, except for bis-diazoacetyl had a negligible effect on the chromosome structure. As to the frequency of induced visible mutations (M1-M3) diazoacetone, nitrosodiethylurea, bis-diazoacetyl and nitrozodimethylurea (88.8-54.3% of mutations) were the most active among 10 studied mutagens.