Optimization of grafted tomato cultivation technology: the role of EM preparations in ensuring high graft-take percentage on Beaufort rootstock

Abstract

The article examines the potential of EM technology integration into commercial vegetable growing of hybrid tomatoes. Purpose. To evaluate the effectiveness of EM preparations (effective microorganisms) in grafted tomato plant cultivation technology and determine their impact on grafttake success rate on Beaufort Tm Cn VF1Fr rootstock. Additional objectives include establishing optimal parameters for preparing grafting components, elucidating the relationship between EM preparation concentration and application method with post-grafting physiological indicators, and determining the potential for integrating EM technologies into commercial hybrid tomato transplant production. Methods. Field trials were conducted during 2019–2021 at the Central Ukrainian National Technical University following the «Methodology of field experiments in vegetable and melon growing». The study utilized grafted tomato plants of Pink Delight F1 hybrid on Beaufort Tm Cn VF¹Fr rootstock. The research included three treatment variants: control without EM technology application, EM5 + EM Agro at standard concentration (1:100), and elevated concentration (1:50). EM preparations were applied by soaking rootstock and scion before grafting (10–15 min) followed by spraying plants in the healing chamber and substrate application. Grafting was performed using the tongue approach method with silicone clips 1,5–2,0 mm in diameter. Plants were placed in a chamber with controlled microclimate (temperature 24–26 °C, relative humidity 85–95 %, 60–70 % shading during the first three days). Over 14 days, graft-take percentage, callus formation rate, morphometric parameters, SPAD index, and frequency of physiological disorders were determined. Results. EM preparation application significantly increased grafted tomato plant survival: EM5 + EM Agro at 1:100 concentration achieved 94.8 % graft-take on day 14 post-grafting versus 82,5 % in control, while elevated concentration (1:50) reached 96,4 %. Callus formation accelerated by 2,4–3,1 days, decreasing from 9,2 days in control to 6,1–6,8 days in EM treated variants. Plant morphometric indicators on day 21 post-grafting improved substantially: height increased by 17,9–25,5 %, stem diameter by 16,7–22,9 %, and leaf surface area by 25,0–35,2 % compared to control. SPAD index in EM treated variants was 15,9–20,4 % higher, indicating better photosynthetic apparatus preservation. Wilting incidence decreased from 24,6 % to 5,2–8,4 %, tissue necrosis from 12,3 % to 1,5–3,1 %, and graft union failure from 5,2 % to 1,5–2,1 %. Economic analysis demonstrated high technology efficiency: standard transplant output increased by 14,9–16,8 %, providing additional profit of 1845–2085 UAH per 1000 grafted plants with return on additional investment of 613–1025 %. Findings. EM preparations are an effective tool for increasing grafted tomato plant survival on Beaufort Tm Cn VF1Fr rootstock. The optimal concentration for production conditions is EM5 + EM Agro 1:100, which ensures graft-take exceeding 94 %, accelerates healing by 2–3 days, and demonstrates the highest profitability (1025 %). The combination of Beaufort rootstock genetic advantages with the stimulating effect of EM preparations on the microbiome provides a synergistic effect manifested in high graft-take, improved morphometric and physiological plant parameters. The technology has significant potential for implementation in commercial tomato transplant production under protected cultivation conditions.