The analysis of the results of phenological observations on 7 phases, which reflect the main moments of seasonal development of plants, was carried out: 1 – the beginning of vegetation, which is characterized by budding and appearance of a cone of leaves; 2 – from the end of the growing season until the phase of massive leaf fall; 3 – the beginning of shooting; 4 – the end of shoot formation; 5 – the beginning of flowering; 6– flowering completion; 7 – massive ripening of fruits. To compare the rhythm of introducers’ development in the new conditions, the European Forsythia, as the most adapted to our conditions variety, was chosen. It was established that under our conditions the vegetation period of Forsythias begins at the late March – early April, when the average daily temperature does not exceed +4 0C, that is, at the general period of vegetation beginning of woody plants. Most of the varietie sunder study start their vegetation by April, 3, when, according to the long-termaverage data, the growing season usually begins. The sum of positive temperatures above 0 0C during this period ranges from 3.2 to 17 0C. Forsythia Ovata begins to vegetate a bit later.
As a result of the research, we have determined that at Forsythias under study the shoot formation began in the third decade of April – the first decade of May. This corresponds to the11.5-18.7 0C average air temperature, with a 25.6-29.8 0C sum of active temperatures above zero. According to duration of the period of shooting and its completion, we have attributed the studied Forsythias to the group with a short (up to 115 days) growth period. According to our observations, in Vinnytsia the flowering periods of Forsythia lasts averagely for 13-15 days. The shortest flowering period – 13 days – was observed at the Forsythia Ovata. The period of fruit formation in the studied Forsythia varieties is rather short (from 18 to 32 days) and depends on the sum of temperatures, terms of the variety flowering, its geographical origin and systematic position.
As a result of the conducted observations, 30% of the annual shoots tips of the Forsythia Suspensa (up to 10-15 cm) were found damaged, but this did not cause a loss of decorativeness, since this species has a high growth rate (50-90 cm), thus there is no reason to claim its complete winter intolerance and low perspectives for its growing. Forsythia Ovata was not bitten by the frost, annual shoots of Forsythia Europaea was slightly frostbite during the frosts at the end of March 2019 at the level of 15% (5-6 cm).
Study of the given species showed that all the Forsythia plants introduced in the territory of the VNAU biostationary show regular growth of shoots, satisfactory level of winter hardiness, formation of seeds capableof germination in Vinnytsia conditions (F. Sus. var. Sieboldii, F. Sus. var. Fortunei).
Key words: biostationary, botanical garden, forsythia, tolerance, vegetation period, acclimatization, winter hardiness, drought resistance.
APPLE TREE LIGHT INTERCEPTION, PHOTOSYNTHESIS, GROWTH, AND YIELD AS AFFECTED BY DIFFERENT ROOTSTOCKS