COLLECTION OF THE PLANT SYMPHYOTRICHUM NEES GENUS IN VYTAUTAS MAGNUS UNIVERSITY BOTANICAL GARDEN
The collection of 82 collection numbers of the plant Symphyotrichum Nees genus has been accumulated in the period of 1923 - 2018 at Vytautas Magnus University Botanical Garden. The collection consists of Symphyotrichum cordifolium, S. dumosum, S. ericoides, S. laeve, S. lanceolatum, S. lateriflorum, S. novae-angliae, S. novi-belgii, S. oblongifolium, S. pilosum, S. × salignum, S. tradescantii, S. turbinellum, S. urophyllum, and their infraspecific taxa and cultones. The major part of the collection consists of S. novi-belgii (32 collection numbers) and S. novae-angliae (19 collection numbers) infraspecific taxa and cultones. 57 collection numbers were acquired by sproutings from other botanical gardens, private collections, nurseries, the origin of 21 collection numbers is unknown, 4 collection numbers were acquired by seed exchange with other botanical gardens. Phenological observations and biometric measurements of plants were performed according to methodological manual "Methodology of phenological observations, biometric measurements and assortment formation of ornamental herbaceous plants" prepared by J. Vaidelys in 2005. When assessing the phytopathological status of plants, powdery mildew (Erysiphe cichoracearum) was determined as the main disease affecting the plants. S. dumosum and S. novi-belgii interspecific taxa and cultones were the most susceptible to the disease. Plants grown in the same location for more than 3 years were more susceptible to the disease. The aim of the study was to review the Symphyotrichum collection and to evaluate the susceptibility of different groups of cultivars to powdery mildew.