Cytogenetic variability of winter wheat (Triticum aestivum L.) under gamma-rays action

Abstract

The aim of our research was to identify the specifity of the action of a wide range of doses of gamma rays in winter wheat varieties at the level of the cell chromosomal apparatus. The experiments used seeds of winter wheat varieties of local selection Spivanka and Commerciyna, irradiated with gamma rays in doses of 100, 150, 200, 250, 300 Gy. Control was dry seeds.

Based on the data of cytological analysis, the frequencies and spectra of chromosomal aberrations after exposure to gamma rays were studied. The total number of mitoses (in the corresponding phase) found in the preparations (20 - 25 preparations for each variant), the number of cells with chromosomal abnormalities and the percentage of such cells (from the number of mitotic), the frequency of chromosomal aberrations (from the total number of cells with rearrangements). The sample was approximately 500 - 1000 cells for each study variant.

The variety Spivanka is significantly less stable with respect to the variety Commerciyna at the cytogenetic level, but with no significant differences in the interaction in the genotype-mutagen system for gamma rays. The number of chromosomal rearrangements increases linearly under the action of gamma rays up to 200 Gy, where a significant drop begins with stabilization at a lower level at doses of 250 - 300 Gy. The dose of mutagen was found as more significant factor. Significant parameters of variability were the total frequency of chromosomal aberrations, the frequency of bridges and the frequency of complex rearrangements. The ratio of fragments to bridges is standard for gamma rays. Approximately the same level of variability in subsequent generations will be assumed for both varieties, but greater differences in variability in case of the use of chemical mutagens and the possibility of differences in the spectrum of changes in subsequent generations for gamma rays was predicted.