Sequential application of budbreak promoters in 'Baigent' apple trees under anti-hail net in southern Brazil: Erger® and mineral oil usage

L.S. Paim, F.J. Hawerroth, G.A.B. Marodin, D.S. Mauta, F. Simões
A single application of hydrogen cyanamide (HC) or Erger® in combination with other compounds has shown insufficient results to budbreak induction of ‘Baigent’ apple trees in a few years in southern Brazil, especially under anti-hail nets. This study aimed to evaluate Erger® in combination with mineral oil (MO) as a sequential application (a second spraying) to budbreak induction of ‘Baigent’ apple trees under anti-hail net, in southern Brazil. The experiment was performed during the 2017/18 and 2018/19 growing seasons, in a commercial apple orchard with black anti-hail net, Vacaria, RS, Brazil. A RCB design was adopted in a 7×2 factorial structure with seven levels of budbreak promoter: 1) control (no application); 2) 1.5% Erger® + 3.5% MO; 3) 1.5% Erger® + 3.5% MO (Application 1 - AP1) and (Application 2 - AP2); 4) 3% Erger® + 3% Ca(NO3)2; 5) 3% Erger® + 3% Ca(NO3)2 (AP1) and 1.5% Erger® + 3.5% MO (AP2); 6) 0.34% HC + 3.5% MO; 7) 0.34% HC + 3.5% MO (AP1) and 1.5% Erger® + 3.5% MO (AP2) and two levels of tree’s canopy portion: 1) lower and 2) upper portion. The axillary and terminal budbreak, fruit set parameters and proportion of the total weight of fruits per tree harvested during commercial maturity were evaluated. The axillary budbreak was increased by using 1.5% Erger® + 3.5% MO as a sequential application after 1.5% Erger® + 3.5% MO, when compared to the respective single treatment. There were no differences in axillary budbreak between tree’s canopy portions in the study conditions. The effect of 1.5% Erger® + 3.5% MO as a sequential application on fruit set data was probably masked. The highest fruit set values were provided by tree’s canopy upper portion. The use of 1.5% Erger® + 3.5% MO as a sequential application after 1.5% Erger® + 3.5% MO is an alternative to the respective single treatment in the budbreak induction of ‘Baigent’ apple trees under anti-hail net, in southern Brazil.
Paim, L.S., Hawerroth, F.J., Marodin, G.A.B., Mauta, D.S. and Simões, F. (2020). Sequential application of budbreak promoters in 'Baigent' apple trees under anti-hail net in southern Brazil: Erger® and mineral oil usage. Acta Hortic. 1268, 297-304
DOI: 10.17660/ActaHortic.2020.1268.40
https://doi.org/10.17660/ActaHortic.2020.1268.40
Malus domestica Borkh., mild winter chilling, endodormancy overcoming, budbreak induction, protected cropping
English

Acta Horticulturae