Cultivation of one-year poplar plants rooted in autumn and spring with the use of different methods of cutting planting material

Purpose. Study of the peculiarities of growing one-year cutting seedlings of four cultivars of the black poplar under the conditions of the Right Bank Forest Steppe using cuttings with a perpendicular and oblique section. 
Methods. Field, laboratory, statistical. 
Results. Cuttings of cultivars ‘Dorskamp’, ‘I-45/51’, ‘Robusta’ and Toropohrytskyi’s poplar 20 cm long were planted in November and early April for three years. The cuttings for rooting were cut from one-year-old shoots using secateurs, with cuts (i) perpendicular to the axis of the shoots and (ii) an angle of 45º. In an average of 3 years, autumn planting of the varieties ‘I-45/51’ (by 6%) and ‘Robusta’ (by 25%) showed better rooting of cuttings with perpendicular cuts. Cuttings of ‘Dorskamp’ variety with oblique cuts rooted by 11 % and Toropohrytskyi’s poplar by 7% better. When planted in spring, the rooting index of cuttings with a perpendicular cut in the ‘Dorskamp’ variety was 24% higher, in ‘I-45/51’ by 30% higher, and in ‘Robusta’ variety 54 % higher. Cuttings with an oblique cut rooted better in Toropohrytskyi’s poplar (by 20 %). The height of the rooted cuttings was the largest for autumn planting of the same variety (192.9 cm). Also, cuttings with an oblique cut had an advantage in height in the variety ‘Dorskamp’ (by 12%). In the varieties ‘I-45/51’ and ‘Robusta’, cuttings with a perpendicular cut had a higher height by 16 and 5 %, respectively. For spring planting, plants of the ‘Dorskamp’ variety had a maximum height, both when using cuttings with a perpendicular cut (197.9 cm), and with an oblique cut (195.6 cm). Plants of the ‘I-45/51’ variety with a perpendicular cut had a height of 149.1 cm and oblique 126.5 cm. In ‘Robusta’, cuttings with an oblique cut were 8% smaller. The cuttings of Toropohrytskyi’s poplar at both planting seasons were taller than cuttings with an oblique cut. 
Conclusions. The effectiveness of using cuttings with a perpendicular or oblique cut depends on the cultivar of poplar, the timing of planting and the weather conditions during vegetation season. In the conditions of the Right Bank Forest Steppe, for the cultivation of Toropohrytskyi’s poplar, it is recommended to use autumn planting of cuttings with an oblique cut. Cuttings of the varieties ‘I-45/51’ and ‘Robusta’ should be planted in autumn using a perpendicular cut, and ‘Dorskamp’ with the same cut, but in spring.