Breeding evaluation of <i>Juglans mandshurica</i> in the green zone of Krasnoyarsk

Abstract

The Manchurian walnut is a highly ornamental tree with large pinnate foliage and a beautiful broadly rounded crown. The species is naturally distributed in Russia in the Far East, as well as in Japan, Korea and North China. It grows in the composition of valley broad-leaved forests on deep, fertile, humus-rich and breathable soils. The Ussuri taiga owes much to its splendor and “tropical” appearance to the Manchurian walnut growing in it. In its homeland, the Manchurian walnut forms large trees, up to 27-29 m in height and 60-70, rarely 90-100 cm in trunk diameter. The root system is powerful, with a deep taproot and well-developed, shallow lateral roots. Trees are wind resistant. Stems are straight. The bark on young trunks is smooth, light gray, on old trunks it is dark gray, with deep longitudinal cracks. The crown is sparsely branched, openwork, on some trees - low-planted, spreading, growing in a plantation – more compact, highly raised. Lives up to 250 years or more. It is of particular interest for breeding work, as it deserves wider use as a valuable food, ornamental and medicinal plant. The fruits are of nutritional and technical importance. Manchurian walnut is the most winter-hardy of all walnut relatives. This paper provides a selection assessment of Manchurian walnut trees of different geographical origin, growing in the green zone of the city of Krasnoyarsk. The aim of the work is to analyze the selection evaluation of Manchurian walnut trees growing in the arboretum of the Siberian State University – an ecologically clean area of the city. When studying the variability, we identified a biogroup that is superior to the rest in height, trunk and crown diameter – B436. Biogroup D160 of Ussuri origin is inferior in size to plants of other biogroups. In 2020–2022, fruiting intensity was studied. Manchurian walnut trees bear fruit annually, but the yield is low: 24-78 fruits per tree. Selected specimens characterized by large-fruitedness and the largest mass of fruits: D 160 (1.2), B 316 (1.2). Given the significant variation in traits, specimens are being selected to obtain breeding planting material adapted to given environmental conditions.