Molecular discrimination and ploidy level determination for elite willow cultivars
Willow (Salix spp.), a woody plant in forms of tree, sub-tree, or shrub, has long been cultivated as an important fiber resource and for environmental protection. To manage commercial willow plantations, there is an increasing demand for the genetic discrimination of willow cultivars based on molecular markers. In this study, based on the genomic sequences of Salix suchowensis, a core set of 16 highly polymorphic simple sequence repeat (SSR) primer pairs were selected for the molecular discrimination of different willow cultivars. Using these primer pairs, DNA fingerprints of a collection of 25 elite willow cultivars were generated and their genetic identities were analyzed based on the SSR genotyping profiles and the UPGMA clustering. Subsequently, we examined the ploidy levels of these cultivars by combining SSR marker genotyping with flow cytometry measurements. It was found that, in this collection, the shrub cultivars were mainly presented as diploids, while cultivars in tree form mainly existed as polyploids. This study established a reference DNA fingerprinting database for managing the commercial willow cultivars, and the determination of their ploidy levels provided critical information for aiding the polyploid breeding programs in willows.
KeywordsWillow Simple sequence repeat (SSR) Cultivar discrimination Ploidy level Flow cytometry
This work was also supported by the Priority Academic Program Development Program of Jiangsu Province. We sincerely thank for the valuable comments from the editor and the anonymous reviewers for formulating the final revision.
This work was funded by the National Key Research and Development Plant of China (2016YFD0600101), the Youth Elite Science Sponsorship Program by CAST (YESS), and the Qing Lan talent support program at Jiangsu Province.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
Data archiving statement
The datasets generated during the current study was deposited at the website: http://184.108.40.206/Database/Salix_integra/. The data will be available to public after the publication of this manuscript.
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