Phenotypic Plasticity and Ornamental Quality of Four Korean Native Veronica Taxa Following Different Light Intensity Treatment

The growth and flowering characteristics of four Korean Veronica species (V. dahurica, V. kiusiana var. diamantiaca, V. pusanensis, V. pyrethrina) were evaluated under various shading levels. Among the study species, V. kiusiana var. diamantiaca has been designated as both an endemic and a rare species (critically endangered) in Korea. V. pusanensis has been designated as both a rare species (data deficient) and an endemic species, as they exist only in Busan, Korea. This study was conducted from March 30 to August 17, 2018 in an experimental plot at the Korea National Arboretum. The study species were cultivated under 0%, 40%, 60%, and 90% shading levels. The fresh shoot weight, number of leaves, and number of branches of V. dahurica grown under 0% – 60% shading levels was significantly higher than when grown under the 90% shading level. The stem caliper of V. pyrethrina grown under 0% – 60% shading levels was significantly higher than under the 90% shading level. V. dahurica and V. pyrethrina grown under 0%, 40%, and 60% shading levels were flowered. Also, time to flowering of V. dahurica and V. pyrethrina grown under 0%, 40%, and 60% shading levels were shorter than when grown under the 90% shading level. The dry weight of the shoots and the visual quality of the kiusiana var. diamantiaca grown under 0% – 40% shading levels were significantly higher than under the 60% – 90% shading levels. The visual quality of V. pusanensis grown under 0%, 40%, 60%, and 90% shading levels were 4.0, 3.0, 2.2, and 1.0, respectively. These results indicate that the four studied Veronica species have different sensitivities to light intensity.