An efficient colchicine mediated chromosome doubling of diploid feverfew followed by the morpho-phenological, physiological, phytochemical and cytological changes of the obtained tetraploid plants was conducted. To achieve this aim, one week-old seedlings of feverfew were treated with 0.05% (w/v) colchicine for 2, 4, 6, 8 and 24 h. Tetraploid plants were regenerated after 4 months, showing significant changes in stomatal size and density, sizes of seed, flower, pollen, leaf, trichome, cell, nucleus, and parthenolide content, chromosome number, ploidy level, chlorophyll content index and quantum efficiency of photosystem II (Fv/Fm). Such interesting characteristics of induced-tetraploid feverfews can be useful in medicinal and ornamental applications, e.g. the study of flower morphogenesis, trichome differentiation and parthenolide biosynthesis.
