Hydrogen cyanamide levels and mineral oil to budbreak induction of 'Baigent' apple trees under anti-hail net in southern Brazil

L.S. Paim, F.J. Hawerroth, G.A.B. Marodin, D.S. Mauta, F. Simões
This work aimed to evaluate concentrations of hydrogen cyanamide (HC) with mineral oil (MO) for budbreak induction of LSQUOBaigentRSQUO apple trees under anti-hail net in southern Brazil. The study was carried out in a commercial orchard with black net, during the 2017/18 and 2018/19 growing seasons in Vacaria, RS, Brazil. A RCB design was adopted according to a 7×2 factorial structure, with seven levels of budbreak promoter (1. Control (no application); 2. MO 3.5%; 3. HC 0.17% + MO 3.5%; 4. HC 0.34% + MO 3.5% (standard application); 5. HC 0.51% + MO 3.5%; 6. HC 0.69% + MO 3.5%; 7. HC 0.86% + MO 3.5%) and two levels of canopy portion (1. Lower and 2. Upper portion). Flowering dates and duration, axillary and terminal budbreak, fructification, and fruit production variables were assessed. Flowering was advanced by HC 0.17% and concentrations above + MO 3.5%, particularly in the upper portion of the canopy with HC above 0.34%. Axillary budbreak was intensified by HC 0.17% and concentrations above + MO 3.5%, markedly with insufficient chilling during winter. The effects of concentrations of HC + MO 3.5% on fruiting were probably masked; the highest values were provided by the upper canopy and fruit production was not affected. Overall, the use of HC above 0.34% + MO 3.5% is an alternative to HC 0.34% + MO 3.5% (standard) to induce budbreak of LSQUOBaigentRSQUO apple trees under anti-hail net in these conditions of southern Brazil.
Paim, L.S., Hawerroth, F.J., Marodin, G.A.B., Mauta, D.S. and Simões, F. (2020). Hydrogen cyanamide levels and mineral oil to budbreak induction of 'Baigent' apple trees under anti-hail net in southern Brazil. Acta Hortic. 1268, 321-328
DOI: 10.17660/ActaHortic.2020.1268.43
https://doi.org/10.17660/ActaHortic.2020.1268.43
Malus domestica Borkh., insufficient chilling, dormancy overcoming, budbreak promoter, protected cropping
English

Acta Horticulturae