Mieslerová B., Lebeda A., Petrželová I., Korbelová P. (2013): Incidence of lettuce downy mildew (Bremia lactucae) and powdery mildew (Golovinomyces cichoracearum) in natural populations of prickly lettuce (Lactuca serriola). Plant Protect. Sci., 39 (Special Issue): S24–S32. The study was focused on the wild pathosystem Lactuca serriola–lettuce downy mildew (Bremia lactucae) and lettuce powdery ...

The primary requirement for a new diploid species to arise via hybridization is ecological divergence from its parental species. Ecological divergence protects the nascent hybrid species from competition with its progenitor species and may contribute to reproductive isolation. However, the means by which hybridization might facilitate the necessary adaptive transitions are poorly understood. He...

The diploid hybrid species Helianthus deserticola inhabits the desert floor, an extreme environment relative to its parental species Helianthus annuus and Helianthus petiolaris. Adaptation to the desert floor may have occurred via selection acting on transgressive, or extreme, traits in early hybrids between the parental species. We explored this possibility through a field experiment in the hy...

Can the complex phenotypes that characterize naturally occurring hybrid species be re-created in early-generation artificial hybrids? We address this question with three homoploid hybrid species (Helianthus anomalus, Helianthus deserticola, Helianthus paradoxus) and their ancestral parents (Helianthus annuus, Helianthus petiolaris) that are phenotypically distinct and ecologically differentiate...

We investigated quantitative trait loci (QTLs) for several leaf chemistry traits in early-generation hybrids between Helianthus annuus and Helianthus petiolaris, the parental species of the ancient diploid hybrid sunflower species Helianthus anomalus, Helianthus deserticola, and Helianthus paradoxus. We grew individuals of a second-generation backcross (BC(2)) toward H. petiolaris under optimum...

Few studies have investigated the causes of evolutionary rate variation among plant nuclear genes, especially in recently diverged species still capable of hybridizing in the wild. The recent advent of Next Generation Sequencing (NGS) permits investigation of genome wide rates of protein evolution and the role of selection in generating and maintaining divergence. Here, we use individual whole-...

Under natural photoperiodic conditions protandry in hermaphrodite disc flowers of sunflower (Helianthus annuus L.) is determined by the different elongation rates of the style and filaments. The elongation of the filament and style starts simultaneously after the daily dark period, but the style growth rate is slower. When plants close to anthesis are exposed to continuous white light (WL) a lo...