PROSPECTS FOR GROWING RHODODENDRONS IN THE CONDITIONS OF THE NORTHERN LISOSTEPPE OF UKRAINE
DOI: 10.35205/0558-1125-2024-79-79-83
UDC 577.10:634:10
PROSPECTS FOR GROWING RHODODENDRONS (RHODODENDRON L.) IN THE CONDITIONS OF THE NORTHERN LISOSTEPPE OF UKRAINE
G.S. MAMCHENKO, Head of the department
Pryluky Research Station of the Institute of Horticulture (IH), NAAS of Ukraine, 17500, Chernigiv region, Pryluky, Vavilov st., 16, e-mail: mgs_71@ukr.net
V.M. YEZHOV, Doctor, Professor, Academician of NAAS of Ukraine
Institute of Horticulture, NAAS of Ukraine, 03027, Kyiv-27, Sadova st., 23, e-mail: ezhow.valeriy@gmail.com
During 2018-2023, the prospects for growing rhododendron hybrids in the Northern zone of the Lisosteppe were studied at the Pryluky Research Station of the IH NAAS. According to the results of the generalized five-year data on the winter hardiness of rhododendron plants, 5 main groups were identified:
1. Highly winter-hardy (9 points) - plants that do not suffer damage. These are such species as evergreen Rhododendrons yakushimanum, Rh. catawbiense Michx, Rh., brachycarpum D. Don.ex y. Don f., semi-evergreen Rh. obtusum, a total of 28 specimens, or 52% of the entire collection.
2. Winter-hardy (7-8 points) - plants in which the apical generative buds were damaged, and browning of evergreen leaves was observed in the crown. These are species Rh. russatum, Rh. carolinianum, Rh. сaucasicum, only 17 species, or 33% of the entire collection.
3. Medium winter-hardy (5-6 points) - they are characterized by damage to one-year growth. This group includes the evergreen variety Rh. Hibrida "Craffito", only 2% of the collection.
4. Weakly winter-hardy (2-4 points) - in typical winters the leaves freeze, and in severe ones the above-ground parts of the bush are significantly damaged. This is the evergreen variety Rh. davissonianum, only 4% of the collection.
According to the methodology, a two-time inspection of the rhododendron collection is carried out every year to identify pathogens. In the second half of the growing season, plants of certain species are affected by powdery mildew Erysiphe azazes (U. Braun): 3 points - Rh. Knaphill hybrid "Cannos Double", "Nabuccо", 5 - Rh. Knaphill hybrid "Scheegold", "Kilian", 7 - Rh. luteum, Rh. molle (Blume), 9 points – Rh. Knaphill hybrid «Fabiola».
According to the complex of economically valuable traits, 14 seedlings were selected, the main advantages of which are the fullness of flower corollas, abundant flowering, straight bush habit, resistance to powdery mildew, winter hardiness. These are the original pairs Rh. Knaphill hybrid «Jack A. Sand» x Rh. Knaphill hybrid «Gold Topaz» (orange flowers), Rh. Knaphill hybrid «Jack A. Sand» x Rh. Knaphill hybrid «Gibraltar» (orange flowers), Rh. Knaphill hybrid «Jack A. Sand» x Rh. Knaphill hybrid «Scheegold» (white-pink flowers), Rh. Knaphill hybrid «Kilian» x Rh. Knaphill hybrid «Fabiola» (pink-orange flowers).
Key words: rhododendron, frost resistance, diseases, vegetation, deciduous, evergreen, species, variety, collection.
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