Abstract
In chrysanthemum, breeders seek for desirable characteristics of the inflorescence, which can first be established once the plant is mature. The present study aims to determine whether measurement of DNA content can be useful in the detection of somaclonal variants and/or separation of chimera components in chrysanthemum at the early in vitro multiplication stage. Eleven Chrysanthemum × morifolium (Ramat.) Hemsl. cultivars of the Lady group (a mother cultivar and ten of its radiomutants obtained by X-ray- or γ-irradiation; solid and periclinal chimeras) were propagated in vitro. Single-node explants were cultured in Murashige and Skoog (MS) medium, either without plant growth regulators (PGRs) or supplemented with 6-benzyladenine (BA) and indole-3-acetic acid (IAA). The nuclear DNA content was measured by flow cytometry (FCM) in the shoots produced in vitro. After acclimatization and growth of the plants in a glasshouse, inflorescence colour was recorded. The addition of PGRs to the medium almost doubled the mean number of shoots produced in vitro per explant, but caused a change in inflorescence colour of all (‘Lady Apricot’; periclinal chimera) or part of the plants (‘Lady Amber’; solid mutant and ‘Lady Salmon’; periclinal chimera). All radiomutants contained less DNA than the mother cultivar ‘Richmond’. There were significant differences in DNA content between plants of the same cultivar grown in media with or without PGRs for ‘Lady Apricot’ and ‘Lady Salmon’, but no phenotype alternation occurred in chrysanthemums produced in PGR-free medium compared to the original cultivars. Conversely, in medium with PGRs, chimeras produced flowers different from the original colour. In all except one cultivar (‘Lady Amber’; solid mutant) a lack of differences in genome size between plants grown in either medium coincided with a stable inflorescence colour. The occurrence of some plants of ‘Lady Amber’ with different inflorescence colour may be due to small DNA changes, undetectable by FCM. It can be concluded that FCM analysis of DNA content in young plantlets can be indicative of the stability of inflorescence colour in chrysanthemum, especially chimeric cultivars, and for mutant detection.
Highlights
Micropropagation is a powerful tool in the large-scale production of ornamental species, including chrysanthemum (Teixeira da Silva and Kulus 2014)
To examine if plant growth regulators (PGRs) influence nuclear DNA content of in vitro produced plants, two types of media were the creation of the cultivars did not affect the proliferation ratio during the single tested multiplication cycle (Fig. 1a)
The present study revealed that all ten radiomutants of the Lady group possessed a lower nuclear DNA content (17.95–18.75 pg/2C) than the mother cultivar ‘Richmond’, regardless of the culture medium used for multiplication (Table 2)
Summary
Micropropagation is a powerful tool in the large-scale production of ornamental species, including chrysanthemum (Teixeira da Silva and Kulus 2014). It has several advantages over the traditional methods of reproduction, such as the high quality of the resultant plant material, more profitable production, and independence of the season (Kulus 2015). Because micropropagation is a clonal method of reproduction, the plant material that is produced is of high uniformity. Due to the use of plant growth regulators (PGRs) and regeneration of plants via unstable callus, a genetic and, phenotypic variation in the in-vitro-derived plants have been reported (Miler and Zalewska 2014)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
