The article investigates the effect of the varietal characteristics of Crimson beebalm (Monarda didyma L.) on the formation of plant material during growing in the conditions of the South Steppe of Ukraine.
The aim of the researche was to investigate the varietal characteristics and planting dates, that affect on productivity of Monarda didyma in the conditions of the South Steppe of Ukraine. Plants on the experimental section were planted of seedlings. Terms of planting were in the spring (the second decade of April) and in the summer (the third decade of May) 2014. Plants in the experiment were planted according to the scheme 30 × 70 cm. The experimental plants were constantly watered. The level of soil moisture was maintained at minimum level of 65-70% field moisture.
In the third decade of March 2015 an active aboveground vegetation of the Crimson beebalm was observed. The average temperature during this period was 1,3-1,6 ͦC. In the conditions of the experiment the difference of the growth rate, development and duration of phenological phases was not determined. The following indexes of culture productivity, such as plant height, number of sprouts, number of leaves, leaf surface area, aboveground vegetative mass were investigated.
The obtained results are showing, that the experimental varieties of the Crimson beebalm has a high adaptive capacity during the first and the second years of vegetation by the cultivation under the conditions of the Southern Steppe in Ukraine. Due to the active tillering 10-15 and 10-19 good shoots with a well-developed leaf area have grown during the first and the second years, respectively. Such assimilating area ensures formation of 40-100 ha/m2 and 320-670 ha/m2 of vegetative aboveground dry mass during the first and the second years of the cultivation, respectively. The plans of the first and the second years of vegetation of all the varieties and planting dates from its most part due to the leaves and the stems, respectively. Comparing the parameters that characterize the above-ground mass of Monarda didyma varieties at the different planting dates, it is obvious, that the spring planting time forwards to the formation of considerably larger plants. It enables to get more dry mass that can be used for obtaining the raw material from one unit of area.
Key words: introduction, productivity, crimson bee balm, variety, assimilation surface.