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An artificial crossing was made between four Viola ×wittrockiana (2n = 48) lines and one Viola cornuta inbred (2n = 26) line as well as among V. ×wittrockiana lines to investigate the cytologic characteristics, fertility, and heteroses of hybrids. The sizes of flowers and stomata and the leaf areas of the V. ×wittrockiana plants were larger than those of the V. cornuta plants. The karyologic stability of V. cornuta was greater than that of V. ×wittrockiana, and ≈20% of individuals in the latter deviated from the given 2n = 48. Capsule setting after interspecies hand pollination ranged from 28% to 94%, and F1 seed germination ranged from 16% to 88%, revealing no obvious pre- or postzygotic selection mechanisms. The chromosome numbers in V. ×wittrockiana × V. cornuta F1 seedlings varied (2n = 34–38), with about half the cells exhibiting the intermediate (2n = 36) value. These interspecific hybrids exhibited positive heterosis in flower size (range, 11% to 66%) and negative heterosis in plant height (range, –12% to –57%). Both of these traits are desirable in pansy breeding programs.

Violets of the section Melanium from Albanian serpentine and chalk soils were examined for their taxonomic affiliations, their ability to accumulate heavy metals and their colonization by arbuscular mycorrhizal fungi (AMF). The sequence analysis of the ITS1-5.8S rDNA-ITS2 region showed that all the sampled six Albanian violets grouped between Viola lutea and Viola arvensis, but not with Viola tricolor. The fine resolution of the ITS sequences was not sufficient for a further delimitation of the Albanian violets within the V. lutea–V. arvensis clade. Therefore, the Albanian violets were classified by a set of morphological characters. Viola albanica, Viola dukadjinica and Viola raunsiensis from serpentine soils as well as Viola aetolica from a chalk meadow were unambiguously identified, whereas the samples of Viola macedonica showed high morphological variability. All the violets, in both roots and shoots contained less than or similar levels of heavy metals as their harboring soils, indicating that they were heavy metal excluders. All the violets were strongly colonized by AMF with the remarkable exception of V. albanica. This violet lived as a scree creeper in shallow serpentine soil where the concentration of heavy metals was high but those of P, K and N were scarce.

Pansies are among the most popular garden flowers today. They exhibit a wide range of colors, markings and sizes.