APPLICATION OF BIOLOGICALLY ACTIVE SUBSTANCES AT THE STAGE OF GRAPE GRAFT PRODUCTION

Abstract

One of the current priorities in the development of grapevine nurseries in Ukraine is the implementation of effective methods for producing high-quality grafted planting material that meets the requirements of biological quality categories (initial, basic, certified). Particular attention in the production of grafted grapevines of such categories should be paid to stimulating the regenerative processes of the components – namely callus and root formation (callusogenesis and rhizogenesis). Biologically active substances play a positive role in this direction and are advisable to use at the stage of soaking the graft components.The aim of the study was to determine the effect of soaking grape scions and rootstocks in solutions of modern biologically active substances on the processes of callus and root formation. Laboratory and comparative-calculation methods were used in the research. The study was conducted on scions of technical, table, and rootstock grape varieties soaked in solutions of the following substances: Charkor, Grandis, Radifarm, Kemira, and Rhizopon (0.8%, 1.0%, 2.0%). The formation of callus and roots was evaluated in comparison with the control (soaking in water). The results showed that Charkor and Rhizopon provided the highest callus-forming activity in scion cuttings. Circular callus along the cut surface was formed in 70–100% of cuttings of most varieties. Among the rootstock cuttings, the highest completeness of callus formation along the cut perimeter was recorded after applying Grandis for the varieties Dobrynia (up to 100%), RхR 4923, and BxR Kober 5BB (over 80%). Charkor and Rhizopon also ensured a consistently high callus-forming response in rootstock cuttings while reducing the number of cuttings without callus. In rootstock components, biologically active substances, in addition to highcallus-forming ability, also promoted active root formation. After treatment with Rhizopon (2.0%), the highest number of roots (up to 20.5 per cutting) was observed in the varieties Dobrynia and RхR4923. The roots had a moderate length (3.0–3.5 cm), which is an advantage for modern grafting and planting techniques in nurseries. In the control group, the number of roots was 2.2 times lower, while their length increased by an average of 11.3 cm. The scientific novelty of the study lies in the comprehensive evaluation of new biologically active substances with a broad spectrum of action to enhance the regenerative properties of graft components in new grapevine forms and cultivars. The practical significance of the study lies in formulating practical recommendations to improve the efficiency of grapevine grafting technology by using biologically active substances with proven regenerative activity.