The phenomenon of dichogamy and the productivity of the species of the genus Juglans L. in conditions of Kyiv Polissya

Abstract

The article deals with the phenomenon of dichogamy of plants of the genus Juglans L. (aged 55 to 65 years) in the collections of the M.M. Gryshko National Botanical Garden of the National Academy of Science of Ukraine (NBS) (Department of Dendrology and Acclimatization of Fruit Plants) and forest plantings in Kyiv. The study of the phenomenon of dichogamy members of the genus Juglans is conducted according to standard techniques. The yield was determined by the method of V.G. Kapper (1930), tree vitality – according to the method of L.S. Savelyeva (1975), statistical processing of the obtained data was performed according to the recommendations of G.M. Zaitsev (1991). It is revealed that according to the dichogamy type, plants are subdivided as follows: protandric trees to 45.9 %; protogenic trees of 50.7 %, and also 2.6 % homogamy trees. Plant J. microcarpa and J. major are represented in the collection of planting NBS by single samples. During the period of studies on the periodicity of fruiting and flowering species of the genus Juglans are not found, the yield is found to be annual. The fruiting period of the Juglans plants lasted the longest for the representatives from the Iran-Turanian floristic region (J. regia) – 127^±8.3 days. The shortest period of fruit development was recorded in plants from the Japanese-Chinese floristic region (J. mandshurica) – 88^±6.4 days. Analyzing the data obtained for the study of dichogamy members of the genus Juglans in conditions of Kyiv Polissya, the authors revealed that tree indicators such as height, trunk thickness, and viability with different type of dichogamy (protandry, protogeny, homogamy) within species, varieties and forms do not differ significantly. However, we statistically confirmed the difference in the indices of yield and fruit weight in all the experimental species with different types of dichogamy. Thus, the yield of homogamy tree types mentioned is higher; the highest figure characterises plants of J. regia (5.9^±0.65). Plants with protandrous type of dichogamy presented lower level of yields. The lowest rate is found of plants J. ailantifolia (4.7^±0.51). Fruit weight was large in protandric trees. This figure is found to be the highest of plants of J. regia (14.5^±0.22). Lower fruit weight was recorded on plants with homogamy type diagam. The lowest indicator is revealed considering plants of J. regia L. f. fertillis (10.1^±0.54). To conclude, the correlation between tree productivity and habitus indices was found. The correlation between the values of tree height, thickness of trunk, its viability and type dichogamy was