Peculiarities of root system and aerial part formation in evergreen boxwood cuttings with twoyear-old and one-year-old wood

Abstract

The study results of the peculiarities of evergreen boxwood rooting (Buxus sempervirens L.) cuttings with two-year wood were presented, regeneration processes in which are insufficiently studied. Also the cuttings with one-year wood, as well as analysis and comparison of biometric indicators of cutting seedlings obtained from the cuttings of both types are presented. The formation and formation of the root system and the growth of the above-ground part of boxwood cuttings were studied at the Uman National University of Horticulture in a greenhouse equipped with a device for finely dispersed moistening. It was investigated that the most effective for stimulating regeneration processes in boxwood cuttings with two-year wood is a solution of β-indolylbutyric acid (β-IMK) with a concentration of 60 mg/l. In cuttings with one-year wood these processes are most effectively stimulated by β-IMK solution with a concentration of 40 mg/l. It was found that cuttings of the first type form more roots compared to cuttings of the second type, they also develop a longer and branched root system. In the optimal version, the cuttings of the first type regenerated 71.3 pieces of main roots, while the cuttings of the second type of roots formed 44.5 pieces. Evergreen boxwood cuttings of the first type form the longest root system – 365.6 cm, while cuttings with one-year wood – 159.7 cm on average for the 2019-2021 research years. Treatment of boxwood cuttings with both two-year-old and one-year-old wood with β-IMK solutions also revealed a significant positive effect on the height of their above-ground part, which in the optimal version exceeded the control version by 1.3 times or by 5.8 cm, and by 1.2 times or by 3.5 cm on average during the research period. The best indicators of economic efficiency are the following: the highest level of profitability – 126.17%, the largest profit – 3246.76 UAH. for the lowest cost of a seedling – UAH 13.26. in terms of 1 m2 of a greenhouse with equipment for fine-dispersed humidification, obtained after growing rooted boxwood cuttings of the first type in the variant using β-IMK with a concentration of 60 mg/l. Thus, the study of the effect of a growth-regulatory substance on the formation of root system and the above-ground part in both types of evergreen boxwood cuttings and the improvement of technological measures for growing seedlings is currently an urgent problem, the solution of which will be provided by the development of scientifically based recommendations for producers of high-quality planting material of this valuable decorative plant. Key words: grafting, number and length of roots, rooting, growing, seedling.