Detection of cytogenetic and genotoxic effects of gamma radiation on M1 generation of three varieties of Triticum aestivum L.

Abstract

The effects of 60 Cobalt (60 Co) gamma radiation on cell division and chromosomal structure in M 1 generations of three varieties (NKU Lider, Bezostaja and GK Beke's) of Triticum aestivum L. genotypes were determined in this study. To understand and compare the tolerance of on three bread wheat varieties to gamma radiation (100, 200 and 300Gy), the frequency of mitotic index, phase indices and genotoxicity rate were scored and statistically interpreted under irradiated and unirradiated conditions, respectively. In parallel with the increasing radiation dose, mean mitotic index rate decreased in NKU Lider and GK Beke's genotypes. 100Gy 60 Co gamma radiation application of NKU Lider was the most powerful genotype to increase mitotic activity as compared to other genotypes. However; depending on increasing dose of gamma radiation, cell division decreased in all studied genotypes except 200Gy application of Bezostaja genotype. Moreover, genotoxicity index of M 1 generation in NKU Lider genotype was decreased in all studied radiation doses with the increasing dose of 60 Co. Furthermore, three different variety of T. aestivum L. seeds treated with different doses of 60 Co gamma radiation showed many aberrant chromosomes such as disorderly prophase, stickiness, uncoiling chromosomes, disrupted equatorial plate, fragment, micronucleus, alignment anaphase, fault polarization, anaphase and telophase bridges, lagging chromosomes and stickiness in all mitotic phases. Consequently, the results suggest that gamma radiation effects are specific to the radiation dose and species, and even show different responses in different varieties of the same species.

The relationship of the efficiency of energy conversion into growth as an indicator for the determination of the optimal dose for mutation breeding with the appearance of chromosomal abnormalities and incomplete mitosis after gamma irradiation of kernels of Triticum turgidum ssp. durum L.

“…The more susceptible cultivars showed a larger reduction in mitotic activity and more chromosomal aberrations (Nazarenko and Kharytonov 2016 ). Oney-Birol and Balkan ( 2019 ) also observed a decrease in mitotic index in two out of three bread wheat cultivars over a dose range of 100–300 Gy gamma irradiation. Azer ( 2001 ) concluded that irradiation with less than 100 Gy was needed to induce 50% abnormal cells in two bread wheat cultivars, while a dose between 300 Gy and 400 Gy were needed to induce the same effect in another cultivar.…”

“…The CBMN assay can, however, not be used for the determination of mitotic indexes and the distribution of micronuclei in daughter cells. The following abnormalities can be observed during mitosis in plants after X-ray and gamma irradiation: stickiness and clumping of chromosomes, diplochromosomes or pseudochiasma, rings, fragments, bridges with or without fragments, micronuclei, giant cells, cellular and nuclear shape deformities, disrupted equatorial plates and uncoiling chromosomes at metaphase (Gupta et al 2019 ; Oney-Birol and Balkan 2019 ). Over time micronuclei can be extruded from the cell, reincorporated in the nucleus, be degraded or persist in the cytoplasm of the cell.…”

Genome size variation and evolution during invasive range expansion in an introduced plant

“…Surveys of intraspecific genome size variation in other systems have documented both broad‐scale variation and conserved genome sizes across populations. For example, natural populations included 1.7‐fold variation in diploid genome size of Brachypodium distachyon (Oney‐Birol & Tabur, 2018 ), and over twofold variation in Synura petersenii (Čertnerová & Škaloud, 2020 ). Conversely, genome size can be a very stable species‐level trait with little observed variation, despite widespread population sampling (e.g., Lysák, 2000 ; Tuna et al., 2019 ).…”

“…In wild barley populations, BARE‐1 retroelement content varied across elevational and aridity gradients, suggesting an association with environmental conditions (Kalendar et al., 2000 ). Multiple systems have identified potential selective effects of elevation on genome size, potentially due to differences in growing season and the fitness effects of development time, as in maize (Bilinski et al., 2018 ), Corchorus olitorius (Benor et al., 2011 ), Lagenaria siceraria (Achigan‐Dako et al., 2008 ), as well as a small number of non‐crop systems such as Dactylis glomerata (Creber et al., 1994 ), and Arachis duranensis (Temsch & Greilhuber, 2001 ), though other results are conflicting (Lysák, 2000 ; Oney‐Birol & Tabur, 2018 ; Tuna et al., 2019 ). Taken together, these studies suggest that intraspecific genome size variation arises because the molecular mechanisms that influence genome size and subsequent structural variation are subject to the same evolutionary processes as other mutations.…”

“…Genome sizes increased toward the leading edge of the invasion, but tended to decrease at higher elevations, consistent with genetic drift during range expansion but potentially strong selection for smaller genomes and faster development time at higher elevations.Surveys of intraspecific genome size variation in other systemshave documented both broad-scale variation and conserved genome sizes across populations. For example, natural populations included 1.7-fold variation in diploid genome size of Brachypodium distachyon(Oney-Birol & Tabur, 2018), and over twofold variation in Synura pe-…”