Genetic diversity of Tulipa suaveolens (Liliaceae) and its evolutionary relationship with early cultivars of T. gesneriana

Polychromatic Tulipa suaveolens occurs over a vast territory ranging from the Crimea to eastern Kazakhstan. Its phylogenetic relationship to cultivated T. gesneriana is still under discussion. We used sequences from the psbE–petL region of chloroplast DNA and the complete internal transcribed spacer of nuclear ribosomal DNA to examine the genetic variability of T. suaveolens specimens from European Russia and the adjoining regions. Our data set also included 8 varieties of cultivated T. gesneriana. The research on biogeographic patterns of plastid haplotype and nuclear ribotype distribution provides evidence that their origin and dispersal over the Lower and Middle Volga Region are linked to the Khazar or Early Khvalynian transgression of the Caspian Sea and subsequent events. In the Crimea and the adjacent regions, the pattern of haplotypes’ distribution indicates that their origin and expansion may be linked to the Karangat transgression of the Black Sea and the subsequent New Euxinian regression. Based on our results, we propose that T. suaveolens is the likeliest wild ancestor of early T. gesneriana.