Evaluation of the Effect of Different Budbreak Promoters on Apple Trees ‘Eva’ and ‘Castel Gala’ in Mild Winter Climate Conditions

Budburst and flowering intensity by the spraying of dormancy-breaking products in ‘Eva’ apple trees

“…Other researchers mentioned that the spraying of 'Eva' with 3% Erger ® + 3% Ca(NO 3 ) 2 or 5% Erger ® + 5% Ca(NO 3 ) 2 increased productivity relative to the control treatment in one evaluated crop, but on 'Castel Gala', no difference was detected (ABREU et al, 2018). The budburst inducers induced larger fruits than the control treatment (Table 1), corroborating the trend seen in several literature studies that show an increase in fruit mass in response to bud burst inducers (ABREU et al, 2018;HAWERROTH et al, 2010b,c;DE MARTIN et al, 2017). There was no difference between the Erger ® + Ca(NO 3 ) 2 and HC + MO treatments.…”

“…Budburst-inducing products that cause a similar result to that of HC may be considered as promising, especially when they present low toxicity since this aspect may restrict HC use in the future (PETRI et al, 2014). The efficiency of Erger ® in inducing increased budburst has already been observed in 'Imperial Gala ' (HAWERROTH et al, 2010b), 'Fuji Suprema' (HAWERROTH et al, 2010b;PASA et al, 2018;UBER et al, 2017), 'Maxi Gala' (UBER et al, 2017), and 'Eva' and 'Castel Gala' apple trees (ABREU et al, 2018).…”

“…Another aspect is that the budburst inducers caused a high number of flower clusters in this year, which increased the competition between the drain tissues and might have led to a carbohydrate deficiency due to the energetic demands from the different drains. Consequently, a reduction of the effective fructification may happen, as observed by Hawerroth et al (2010a,b), and Abreu et al (2018).…”

“…Pasa et al (2018) reported the budburst of axillary buds, in plants exposed to 2, 4 and 6% Erger ® , was below the 0.34% HC + 3.2% MO standard treatment on 'Fuji Suprema' apple tree while the budburst of apical buds was high, even without the spraying of inducing chemicals (control treatment). According to Abreu et al (2018), 3% Erger ® was superior to 1.5% HC + 3% MO at triggering increased budburst on 'Eva', whereas, both treatments had similar outcomes when applied to 'Castel Gala'.…”

“…However, high doses, such as 4 and 5% Erger ®, caused phytotoxicity, mainly on branches which had late growth, possibly because of inadequate lignification. 2018; UBER et al, 2017), 'Maxi Gala' (UBER et al, 2017), and 'Eva' and 'Castel Gala' apple trees (ABREU et al, 2018).…”