Flower Yield of Arnica sp. Cultivated in Two Floristic Regions in Bulgaria

An experiment was conducted to evaluate the impact of climate and soil conditions on arnica plant development with different origin in two floristic regions at Vitosha Mt. and Rhodopi Mts. in Bulgaria and to calculate the yield of Arnicae flos from the studied collections. The measurements were done at Faculty of Pharmacy, Medical University, Sofia, Bulgaria, between May 2010 and June 2013. The altitude of the experimental fields was determined by General Positioning System and the exposition was established by compass. Climatic areas and regions were classified and the soil type was defined. The meteorological data for monthly average temperatures and rain falls for the experimental areas during the investigated period were given by National Institute of Meteorology and Hydrology, Bulgarian Academy of Science. The flower head diameter has been measured during the full flowering stage on 50 model plants. The data were statistically processed by Medcalc Program. Harvesting of plant substance Arnicae flos of 3-year old A. montana and A. chamissonis was performed by hand picking at full flowering stage. The results showed a significant difference in the origin of the herbal drug in the carried out study. Regarding to A. montana, advantageously greater yield was obtained from plants originating from Ukraine at both fields. Depending on the methods of propagation, higher values were obtained by in vivo seedlings, up to 268 kg/ha. With regards to the experimental area, on Vitosha Mt. the yield was approximately the same for both origins regardless of the method of propagation while at Rhodopi Mts. significantly greater was the yield of in vivo seedlings compared to in vitro seedlings. Concerning A. chamissonis, there was a predominantly higher yield at Vitosha Mt. compared to Rodopi Mts. (58 kg/ha and 35 kg/ha, respectively) and showed values up to four times less compared to A. montana. Both experimental areas had similar ecological characteristics, but the presence of much air humidity and soil moisture at Rhodopi Mts. implied a better plant development and bigger yield. The cultivation of Arnica sp. in mountainous regions in Bulgaria has been proved to be perspective and the country appears to be a promising source of plant substance Arnicae flos.