Abstract
Here we report the cytogenetic characteristics of variability of mutation induction in new wheat varieties and some relationships between the means of the cytogenetic characteristics and different doses and types of mutagens. Analysis of chromosomal aberrations caused by mutagenic action of any kind of mutagen by the meto-anaphase method is one of the best known and most precise methods which we can use for determining the fact of mutagenic action on plants, and identifying the nature of the mutagenic factor. The strategy of investigation combined the identification of genotypes with a specific low-sensitivity to mutagenic factors using cytological analysis screening of mutagen treated wheat populations with the approach of comparing different varieties by breeding methods to reveal their connections and differences, specific sensitivity to mutagenic effects on the cell level. Dry seeds of 8 varieties of winter wheat were treated by nitrosomethilurea at concentrations 0.0125%, 0.0250%, and nitrosoethilurea 0.010%, 0.025%, which are normal levels for mutagenic selection of winter wheat mutation. The frequency and spectra of chromosomal aberrations were investigated. The overall correlations between the frequency of chromosomal aberrations and the value of a concentration were at the level 0.7–0.8. It was established that the fragments-bridges ratio is a reliable parameter for identifyingthe nature of mutagen. We identified genotypes and groups of genotypes which have a resistance to different types of mutagenic action. The resistance of a group is dependant on the breeding method of the variety initially obtained. It expressed as a decrease in the frequency of aberrations. Varieties obtained through chemical mutagenesis were less sensitive to the same chemical mutagens. Higher rates of chromosomal aberrations were typical for varieties obtained through field hybridization without any mutagen treatment or when the initial material was changed by low temperatures.
Highlights
Experimental mutagenesis studies the effects of any mutagen on living organisms
The following winter wheat varieties were treated by mutagens Favoritka, Lasunya, Hurtovina, line 418, Kolos Mironovschiny, Sonechko (chemical mutagenesis, nitrosodimethilurea (NDMU) 0.005%) and Kalinova, Voloshkova in dry seeds-form
Cases with two or more types of aberrations in one cell and fragments-bridges ratio were calculated separately (Table 2). After these data had been analyzed,we identified some correlations between mutagen concentrations and parameters of spectra
Summary
Experimental mutagenesis studies the effects of any mutagen on living organisms. This includes radiation across the electromagnetic spectrum including X-rays, ultra-violet radiation, visible light, microwaves, radio waves, emissions due to radioactive decay, low-frequency radiation such as ultrasound, heat waves and related modalities, chemical and biological agents (Waugha, 2006). At the beginning of mutation research, over 100 years ago, these sudden changes were observed and detected by the phenotypes they affected. Translocations are most important for mutation breeding types of chromosome aberration, which may result from the rejoining of broken chromosomes. Irradiation tends to induce chromosome breaks, which can rejoin at random, resulting in translocations. Cytological aberrations observed in mitosis include the production of micro-nuclei and chromosomal abnormalities (Ukai, 2006; Shu et al, 2011)
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