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Stable mutations observed in the M2 population of Salvia coccinea treated with ethyl methanesulfonate (EMS). (A) S. coccinea untreated control, (B) leaf deformation from Expt. 1 with exposure to 0.8% EMS for 12 h, and (C) chlorina mutation from Expt. 1 with exposure to 1.2% EMS for 8 h. (D-G) Mutations from Expt. 2 with exposure to 1.2% EMS for 8 h. (D) Sectorial chimera, (E and F) differential gene expression, and (G) leaf deformation. |
Athens, GA: Salvia coccinea, commonly known as Scarlet Sage, is cherished for its vibrant red flowers and its ability to attract pollinators such as hummingbirds and butterflies. However, like many plants, it faces challenges due to environmental stresses and diseases. The application of ethyl methanesulfonate (EMS), a chemical mutagen, has enabled researchers at the University of Georgia Department of Agriculture to induce beneficial genetic mutations in Salvia coccinea, potentially leading to new varieties with improved traits.
There is a continual market demand for ornamental plants with new characteristics. If limited natural variation exists, mutation breeding can improve a crop by artificially inducing genetic variation. This breeding technique has been shown to cause phenotypic variations in color, flower shape, plant height, and leaf chimeras. Chlorophyll mutations are the most common and reliable way to determine the efficacy of treatments; however, most induced mutations are recessive and cannot be segregated until the M2 generation.
An experiment was designed to determine the optimum treatment parameters to induce mutations in S. coccinea. Twelve different treatment groups were tested by varying exposure time and concentration of the chemical mutagen EMS to form a two-way factorial. The first factor, with three levels, tested the mutagenic impact of exposure time by using an 8-, 12-, or 24-h treatment period. The second factor, with four levels, tested the impact of mutagen concentration by using 0%, 0.4%, 0.8%, or 1.2% EMS. Finally, the experiment had three replicates of 18 seeds in each treatment group.
The table below is a summary of the stable mutations isolated in the M2 population. (A) S. coccinea untreated control, (B) leaf deformation from Expt. 1 with exposure to 0.8% EMS for 12 h, and (C) chlorina mutation from Expt. 1 with exposure to 1.2% EMS for 8 h. (D-G) Mutations from Expt. 2 with exposure to 1.2% EMS for 8 h. (D) Sectorial chimera, (E and F) differential gene expression, and (G) leaf deformation.
Mutagenesis can lead to the development of plants with increased resistance to diseases, pests, and environmental stresses. New mutations can result in novel flower colors, improved bloom times, and enhanced aesthetic appeal. By creating hardier plant varieties, mutation breeding supports sustainable agricultural practices and reduces the need for chemical interventions.
Future work will investigate the stability and heritability of chlorophyll variegation by hybridizing these selections with coral-flowered accessions of S. coccinea
The full article can be read on the HortScience electronic journal website at: https://doi.org/10.21273/HORTSCI17092-23
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