Polyploid plants grow well, are stress tolerant, and are rich in nutrients and bioactive compounds. Thus, they are useful for improving crop quality and yield. In this study, we compared the seed characteristics and metabolite profiles of diploid and tetraploid tartary buckwheat, which was developed via an artificially induced chromosome doubling event. The length, width, area, and thousand-grain weight were greater for the tetraploid seeds than for the diploid seeds. However, the germination rate decreased for the tetraploid seeds. Additionally, there was a gap between the shell and kernel of the tetraploid seeds. Moreover, the water absorption rate was higher for the tetraploid than for the diploid seeds. Chromosome doubling increased the seed total flavonoid content and deepened the seed color. A principal component analysis of the ultrahigh-pressure liquid chromatography-high resolution mass spectrometry data revealed the clear separation between the diploid and tetraploid samples. An orthogonal partial least squares-discriminant analysis and other multivariate statistical analyses identified 83 differentially abundant compounds, with most of the flavonoid metabolites more abundant in the tetraploid than in the diploid seeds. Research on tartary buckwheat polyploidy may result in enhanced germplasm resources and may clarify the mechanism underlying the biosynthesis of bioactive compounds.

Tartary buckwheat; diploid; tetraploid; seed