The thesis is devoted to studying biological and ecological features, introduction and practical use of three species of Pyracantha M.Roem. genus, originating from different floral regions and introduced into the conditions of the Right-Bank forest- steppe of Ukraine.
According to the APG IV (2016) taxonomic classification system for flowering plants, the Pyracantha genus belongs to the subfamily Amygdaloideae Arn., the Rosaceae Juss. family and the Rosales Bercht. & J. Presl. order. There are 11 species according to the Plant list.
The areas of natural and cultural distribution of species of the Pyracantha genus are revealed. As the first representative in Ukraine, P. coccinea M. Roem. had been introduced into the culture in 1629 in the Western part of the Southern coast of Crimea.
A collection of four species and nine cultivars of Pyracantha has been created in the National Dendrological Park “Sofiyivka” of the National Academy of Sciences of Ukraine. They are the following: P. coccinea, P. crenatoserrata (Hance) Rehder.,
P. crenulata (Roxb. ex D. Don) M.Roem., P. koidzumii (Hayata) Rehder; P. H 'Orange Charmer', P. × 'Red Column', P. × 'Soleil d'Or', P. × 'Red Cushion', P. x 'Lomecia elegancitsime' P. rogersiana 'Golden Charmer', P. fortuneana 'Orange Glow',
P. coccinea 'Lalandii' and P. coccinea 'Kasan'.
The features of the seasonal rhythm of the Pyracantha genus plants development,
which are consistent with the rhythm of the weather and climatic conditions of the Right-bank Forest-Steppe of Ukraine, have been defined. The beginning of vegetation is the end of March's third ten-day period and lasts 195-215 days. The end of the linear growth of shoots is at the end of October's second ten-day period. The period of leaf growth is 48-54 days, and the period of leaf life is 12-18 months. The generative period of Pyracantha occurs at the age of 5-6. Flowering lasts from 9 to 16 days, and mass ripening of fruits is from the second ten-day period of August. The average date of emergence of plants of the genus from deep dormancy and entry into forced dormancy is the third ten-day period of December, with 41±2 days for P. coccinea, 32±3 days for
P. crenatoserrata, and 34±5 days for P. crenulata.
Based on the analysis of ecological features in the Right-bank forest-steppe of Ukraine, the Pyracantha genus plants are mesophytes, mesatrophs, and facultative heliophytes. The limiting factor is the relatively low winter and frost resistance.
P. x 'Orange Charmer', P. coccinea, P. crenulata, P. crenatoserrata, P. x 'Red Cushion' and P. x 'Soleil d'Or' were the most winter-tolerant during the observation period.
The most diverse features of the pyracantha's vegetative and generative organs are the length of the leaf blade (P. сoccinea – 27,04%; P. crenatoserrata – 28,56%, and
P. crenulata – 29,88%). The variation coefficients of a petal width are the following:
P. сoccinea – 25,14%; P. сrenatoserratа – 25,18%. P. сrenulata – 25,94%. The lowest coefficient of variation was recorded for the leaf blade width in P. сoccinea – 8,95%;
P. сrenatoserratа – 9,24%. P. сrenulata – 6,28%. The seed weight of P. сoccinea was 4,24%; P. сrenatoserratа – 4,03%, and P. сrenulata – 4,36%.
Recommendations for seed and vegetative propagation have been developed. The best results were obtained when sowing freshly harvested seeds in the first ten-day period of October. Mass seed shoots appeared in the second ten-day period of April. The average rate of stratified seeds germination for two years is 77 ± 2,9%, in P. coccinea, 75 ± 5,8% in P. crenatoserrata, 77,5 ± 9,2% in P. crenulata, and 76,5 ± 5,3% in P. koidzumii. The best indicators of cuttings’ rooting were obtained in fine moisture conditions when planting semi-woody cuttings in a peat substrate KST (2:1:1). It gave 100% rooting and green cuttings using heteroauxin 100 mg / l -90% rooting.
The decorative value of the Pyracantha genus plants is high and ranges from 4,4– 5,0 points. The decorative effect of the plant is preserved throughout the year and is promising in decorative gardening. It can be used in creating compositions in the form of tapeworms, groups for rocky slides when creating one-species garden and hedges.
The introduction success is analyzed, and the prospects for using the studied species in culture in the conditions of the Right-bank forest-steppe of Ukraine are defined. It was found that the introduced plants of the Pyracantha genus are characterized by good aclimatization of P. coccinea (90), P. crenatoserrata (80), and P. crenulata (80). P. coccinea (83), P. crenatoserrata (76), and P. crenulata (81) are promising species for growing in culture according to the assessment of their introduction success.
