Grafted grape seedlings development depending on the rootstock’ length and variety

The aim of research is to study the influence of the length and variety of the rootstock on the agrobiological indicators of grafted grape seedlings. In 2019-2020 on the experimental field of the Federal State Budgetary Scientific Institution ARRIVandW - branch of the FRASC, an experiment was made in three replicates of 50 plants on the scion variety Denisovsky and rootstocks Kober 5BB and Riparia Rupestris 101-14. Experiment scheme: option 1 - rootstock 30 cm long; option 2 - 35 cm; option 3 - 40 cm; option 4 - 45 cm (control). The grafting was carried out according to the generally accepted in production technology of table grafting with a one-eyed scion cuttings according to the variants of the experiment, nursing work was standard for an irrigated school. The regenerative activity of grafted grape cuttings was determined by the method of L.M. Maltabar, N.I. Melnik (2004) and the formation of callus in the average sample of inoculations by the method of L.V. Kolesnikov (1968), after stratification in the chamber, the nature of the survival rate, growth and development of seedlings in a school was determined, the development of the root system - according to the method of L.V. Kolesnikov (1968) and the output of first-class grape seedlings from the school - according to the generally accepted method (in accordance with GOST 31783-2012). It was found that with a rootstock length of 30 cm, an increase in the yield of grafts from the chamber up to 82.65 %, survival rate - up to 82.5 % and the final yield of seedlings - up to 52.4 cm was observed. The rootstock variety had the greatest influence on the quality of seedlings. The stock-rootstock combination Denisovsky × Kober 5 BB has a low seedling yield from 15.5 to 24.6 %, which is lower than the Denisovsky × Riparia Rupestris 101-14 combination with a seedling yield from 36.4 to 52.4 %. A positive dependence of the yield of grafted seedlings of the Denisovsky variety with a rootstock Riparia Rupestris 101-14 and a rootstock length of 30 cm and a rootstock length of 30 cm was revealed in comparison with the widespread variety of rootstock Kober 5 BB and a length of 45 cm.