Mutation breeding

About: Mutation breeding is a research topic. Over the lifetime, 531 publications have been published within this topic receiving 6730 citations. The topic is also known as: variation breeding.

Phenotypic and molecular cytogenetic variability in calendula ( Calendula officinalis L.) cultivars and mutant lines obtained via chemical mutagenesis

Abstract: The morphological, meiotic and chromosomal variability were studied in two cultivars of Calendula officinalis L. and their mutant lines obtained though chemical mutagenesis using diethyl sulphate (DES) (0.04%, 0.08%) and dimethyl sulphate (DMS) (0.025%, 0.05%). The studied cultivars displayed different sensitivity to DMS and DES mutagens. More M1 plants with morphological changes were observed in C. officinalis cv. ‘Zolotoe more’ than in cv. ‘Rajskij sad’. DMS and DES at low concentrations had positive effects on main agro-metrical traits in both cultivars including plant height, inflorescence diameter and number of inflorescences per plant. Dose-dependent increase in number of various meiotic abnormalities was revealed in both mutant lines. Comparative karyotype analysis and FISH-based visualization of 45S and 5S rDNA indicated a high level of karyotype stability in M1 and M2 plants. Seed treatments with DMS and DES at certain concentrations resulted in higher yields of inflorescences in M1 plants compared to the control. In M2 generation, dose-dependent reduction in the yields of inflorescences was observed. Our findings demonstrate that DMS and DES at low concentrations have great potential in calendula mutation breeding.

Mutation breeding of grain legumes

Abstract: Genetic variation among existing cultivars and in germplasm collections is the outcome of selection during evolution and plant breeding. Mutagenesis offers the plant breeder a chance to tackle unconventional objectives, particularly those that were at a selection disadvantage in the past. Effective mutagens are available, but the bottleneck is the effective selection of rare desired variants from large mutagenized populations. Selection methods must be non-destructive. Grain legume mutation breeding has already led to improved cultivars with higher yield, better grain quality, or stronger resistance to pathogens. Many mutations affecting nitrogen fixation related traits have also been reported. Some could be useful in breeding better cultivars, but the majority are being used to study the factors interacting in the complex process of symbiotic nitrogen fixation and to improve the strategy for producing cultivars with better fixation capacity.

Molecular characterization of proton beam-induced mutations in soybean using genotyping-by-sequencing

Abstract: Proton beam irradiation is a next-generation technique to develop mutant crop varieties. The mutagenic effects and molecular mechanisms of radiation are important multi-disciplinary research subjects. This study was conducted to investigate the types of mutations induced in the soybean genome by proton beam irradiation. In total, 22 plants, including 10 M2 plants treated with proton beam irradiation at 118 and 239 Gy, each, and two wild-type plants (Daepung) were sequenced by genotyping-by-sequencing (GBS). In total, 7453 single nucleotide polymorphisms (SNPs) were detected in the 20 M2 plants, compared with the two wild-type controls. The SNP frequency was 1/36,976 bp with proton beam irradiation at 118 Gy, and 1/32,945 bp at 239 Gy. Of these, 3569 SNPs were detected in genic regions. We observed that proton beam irradiation induced more substitutions than small insertion–deletions (INDELs). Based on the mutagenic effect of proton beam irradiation, the frequency of transition mutations was shown to be higher than that of transversions. The proton beam-induced SNPs were distributed uniformly in most of the chromosomes. Gene ontology (GO) analysis showed that there were many genes involved in protein metabolic process under biological process, intracellular membrane-bounded organelle under cellular component, and nucleic acid binding under molecular function. This study could provide valuable information for investigating the potential mechanisms of mutation, and guidance for developing soybeans cultivars using mutation breeding.

Mutation breeding in sunflower for resistance to alternaria leaf spot

Abstract: SUMMARY Genetic variability for resistance to Alternaria leaf spot disease (Alternaria helianthi) can be induced by radiation or chemical mutagens. The objectives of this study were to create genetic variability in cultivated sunflower and to select lines resistant to Alternaria leaf spot. In the first experiment, sunflower seeds of the genotype HA BR 104 were irradiated with 150 and 165 Gy of gamma rays. Seeds were sown in the field at the Embrapa Soybean experimental station, in Londrina, PR, Brazil and M1 plants were harvested in bulk. M2 ,M3 and M4 plants were screened for disease resistance under natural infection in the field. Plants were evaluated for Alternaria leaf spot symptoms, using a diagrammatic scale from 0 (no symptoms) to 5 (maximum infection). Before flowering, plants showing no symptoms of Alternaria leaf spot (grade 0) or less than 5% diseased leaf area (grade 1) were bagged for self-pollination. Self-pollinated plants and open-pollinated plants from 150 Gy and 165 Gy populations with no or mild disease symptoms were selected. In the second experiment, sunflower seeds of the genotypes HA 300 and HA BR 104 were treated with ethyl methanesulfonate (EMS) at 0.015 mol dm -3 . Selected M2 and M3 were screened for disease resistance in the field. From the EMS treatment, 300 M3 plants with no disease were recovered. All these lines will be tested for combining ability. The best lines will be used for hybrid production.

Determination of mutagenic sensitivity to gamma rays in ginseng ( Panax ginseng ) dehiscent seeds, roots, and somatic embryos

Abstract: Ginseng (Panax ginseng) has a low genetic diversity and a narrow pool of genetic resources. Mutagenesis is one of the most powerful methods for inducing genetic variation in this species, but little research has been performed in ginseng. In this study, various tissues, including dehiscent seeds, 1-year-old roots, and somatic embryos were irradiated at different doses of gamma rays (20–400 Gy and zero dose as a control) to determine the most optimal concentration and tissues for the successful use of mutagenesis in ginseng breeding. The results revealed that high gamma doses (> 100 Gy) were detrimental to all irradiated tissues. A gradual and significant reduction in germination, emergence, and seedling growth were found as gamma irradiation dose increased. The reduction in survival rates and seedling growth by irradiation at serial doses showed that the LD50 of ginseng was 20–80 Gy, although the irradiation doses were tissue dependent. Based on our results, the optimal doses of gamma rays for inducing mutation in ginseng are < 20, 40, and 60–80 Gy for 1-year-old roots, dehiscent seeds, and somatic embryos, respectively. Given the fact that ginseng somatic embryos are less sensitive to gamma rays than other tissues, the combination of in vitro culture and mutagenesis could be more effective than the conventional method for mutation breeding in ginseng. These results provide a good basis for radiation sensitivity of ginseng and are useful as a guideline for ginseng mutation breeding.