Raleio na pré-floração, brotação e produção em laranjeiras sob aplicação de ácido giberélico produzidas na região Sul do Rio Grande do Sul

Abstract

This work aimed to study the reduction of flowering, the distribution of shoots and fruiting under different concentrations of gibberellic acid (AG3) in orange trees for two consecutive crops in the city of Pelotas, RS. The experimental design was in blocks, with five replications, and the experimental unit consisted of five plants. The treatments comprised two cultivars (Lane Late and Navelina) and five concentrations of gibberellic acid (AG3) (0, 20, 40, 60 and 80 mg L-1). The variables evaluated in the two production cycles 2019/2020 were: number of flowers, budding categories and fructification. In the first production cycle, regardless of cultivar, GA3 applications had no effect on the evaluated variables. However, in 2020, when using the concentration 80 mg L-1 applied on June 20, there was a positive effect for 'Lane Late' which presented a drastic reduction in flowering (275.4 flowers/m2) when compared to control (1812.8 flowers/m2). The classification of shoots was also changed, with a reduction of inflorescences without leaves and with leaves, in 87.56% and 77%, respectively. The vegetative shoots increased by 211% for the same concentration of AG3 and the fruit production had an increase of 59.52% compared to the control treatment, although it is still considered low for the cultivar. Regarding 'Navelina', AG3 applications did not result in significant differences, possibly because they did not coincide with the floral induction period.