Application of mechanical stimulation for overgrowth retardation to tomato grafted seedlings using air circulation fans in greenhouse

Abstract

This study was conducted to examine the overgrowth retardation effect on tomato (Solanum lycopersicum L.) plug seedlings by using an eco-friendly method that gives mechanical stimulation to plants using air circulation fans. Two cultivars of tomatoes, ‘Dotaerangdia’ and ‘B-Blocking’ were used as scion and rootstock for tomato grafted seedlings. Tomato seedlings were planted in 40-cell plug trays filled with commercial growing medium and given the wind treatment. Wind treatment scales were set with 2, 4, or 8 m s-1 (average wind velocity range at a growing point in the middle of the tray). The wind treatments were started on July 3, 2018 and carried out for 20 days during 10 h daily. Non-treatment was set as the control. Diniconazole treatment was set to compare the conventional methods. Plant height, number of leaves, leaf area, chlorophyll fluorescence (Fv/Fm), and dry matter tended to grow smaller in all wind treatments. As the wind velocity increased, shoot dryness, the breakage of grafted union, and medium dryness of seedlings were observed. Thus, the results of this study indicate that wind treatments have an overgrowth retardation effect in tomato grafted seedlings. Moreover, it was also considered that wind treatments have a possibility of replacing plant growth regulators; and 2 m s-1 can be a proper wind treatment for overgrowth retardation of tomato grafted seedlings growth. ? 2020 International Society for Horticultural Science. All rights reserved.