Ácido abscísico e caracterização da uva ‘Niágara Rosada’ em clima temperado

Abstract

‘Niagara Rosada’ is the main common grape cultivar planted in Brazil for fresh consumption; however, information regarding the production of this cultivar in the southern region of Rio Grande do Sul is scarce. Thus, the objective of this work was to evaluate the phenology, the thermal demand, the production and the physicalchemical characteristics, besides the evolution of ripening and the application of abscisic acid (S-ABA) in the ‘Niágara Rosada’ grape in the city of Pelotas-RS. The work was divided into three experiments. The grapevines were grown in trellis system, with 2.5 spacing between rows and 1.85 m between plants. In the first stage, the phenology, thermal demand and production of this cultivar were evaluated in PelotasRS, in the harvests 2018/2019 and 2019/2020. The phenology was determined in days, while the thermal demand was calculated using the sum of degree days. In both harvests, the evaluation was carried out from pruning to the gem-cotton subperiods, budding, inflorescence emergence, flowering, veraison, and harvest. Physical and productive characteristics were also evaluated. In the second stage, the evolution of grape maturation was evaluated and for this, from the beginning of maturation until harvest, the soluble solids content (SS), pH, titratable acidity (TA) and SS/TA ratio were analyzed. The third experiment aimed to evaluate the effect of S-ABA on the physicochemical characteristics of ‘Niagara Rosada’ grapes in the same region. S-ABA was applied at different concentrations and times, as follows: a) control; b) S-ABA 200 mg L-1 in veraison; c) S-ABA 400 mg L-1 in veraison; d) S-ABA 200 mg L-1 in veraison + 200 mg L-1 at 20 days after the first application; e) S-ABA 400 mg L-1 in veraison + 400 mg L-1 at 20 days after the first application. Regarding the first chapter, the duration of the cycle was one day longer in the first evaluated harvest, which occurred in 150 days; however, the thermal demand was higher in the second harvest. Regarding the physical characteristics, in the first harvest there was a greater number of bunches, production per plant and productivity, concluding that ‘Niágara Rosada’ has good adaptability to the conditions of the region. In the second experiment, it was found that in both vintages evaluated, the Niagara Rosada cultivar has compatible maturation evolution in the region under study. In the third experiment, the application of S-ABA did not influence the physical characteristics of the grape; however, independent of the concentration, a higher content was obtained for soluble solids, SS/TA ratio and anthocyanins in relation to the control. There was a higher content of phenolic compounds in the control and in the grapes in which an application of 200 mg L-1 in veraison was made. Thus, only one application of 200 mg L-1 of S-ABA in veraison is sufficient to improve the attributes in the ‘Niagara Rosada’ grape. It is concluded that the ‘Niagara Rosada’ cultivar presents satisfactory development and production characteristics in the Pelotas-RS region, which are enhanced with the use of S-ABA.