Thidiazuron with Mineral Oil as Alternative Bud Break Promoter for Apple Trees

Aims: This work aims to evaluate the efficiency of Revent® 500 SC (Thidiazuron) concentrations as a bud breaker promoter in apple trees, cv. Maxi Gala and Supreme Fuji, through phenology, sprouting of buds, fruit set and production per plant.

Place and Duration of Study: The experiments were carried out in southern Brazil, municipality of Caçador / SC, during the seasons from 2017 to 2019, in the cultivars Fuji Suprema and Maxi Gala / Marubakaido / M9.

Methodology: The treatments were 1. Control (without application); 2. Mineral Oil (MO) 3.5% + Hydrogenated Cyanamide (HC) 0.35%; 3. MO 3.5% + HC 0.5%; 4. MO 3.5% + Thidiazuron (TDZ) 0.005%; 5. MO 3.5% + TDZ 0.01%; 6. MO 3.5% + TDZ 0.015%; 7.MO 3.5% + TDZ 0.02%; 8.MO 3.5% + TDZ 0.025%, applied in stages B and C. Several variables were evaluated such as phenology, sprouting of axillary and terminal buds, fruit set, production per plant and average fruit mass.

Results: All treatments with bud breakers advanced the phenological stages in relation to the control in the three years. In the sprouting of the axillary and terminal buds, all treatments were superior to the control. TDZ treatments showed higher sprouting of axillary buds in 2017/18 compared to standard treatments with hydrogenated cyanamide. In plant production, the treatment MO 3.5% + TDZ 0.02% was higher than the other treatments in the 2018/19 and 2019/20 seasons, in both cultivars. TDZ associated with mineral oil is efficient in inducing the sprouting of ‘Maxi Gala’ and ‘Fuji Suprema’ apple trees and can be used to recover sprouts from previous years.