The color of the berry grapes is due to existence of anthocyanins and their accumulation seems to be regulated, at least in part, by abscisic acid. Therefore, exogenous applications of this regulator may increase the anthocyanins concentration in the grapes skin. The objective of this study was to evaluate the effect of abscisic acid on the color of berries and in the anthocyanin accumulation and total phenolic compounds of 'Rubi' grapes. The 'Rubi' grape (Vitis vinifera) variety was studied in the sixth year of production. The experimental design was randomized blocks, with 4 treatments and 6 replications. The treatments consisted of isomer concentrations of (S)-cis-abscisic acid (S-ABA), as follow: Control (0 mg L-1); 400 mg L-1 de S-ABA at the beginning of the maturation (BM); 400 mg L-1 at BM + 200 mg L-1 at 25 DAFA (25 days after the first application) and 400 mg L-1 in BM + 400 mg L-1 at 25 DAFA. The berry bunches were sprayed in the morning, using costal sprayer providing full and uniform coverage. The colorimetric characteristics were determined with colorimeter obtaining the following variables: luminosity, saturation, hue angle and color index. The fresh mass, length and width of bunch (berries and stems), number of berries per bunch, soluble solids, titratable acidity, soluble solids/acidity ratio, pH, reducing sugars, anthocyanins, and phenolic compounds were evaluated. The abscisic acid (S-ABA) promoted the physical characteristics of the bunch and berries slightly with no effect on the stems. However, it triggered significant increase in soluble solids content and in the soluble solids/acidity ratio. It also increased the anthocyanin and total phenolic compounds, especially when applied twice, regardless of the concentration, in addition to improve color attributes. It is recommended the application of 400 mg L-1 at BM + 200 mg L-1 at 25 DAFA can be useful to increase anthocyanin and total phenolic and to improve color attributes.

The objective of this study is to evaluate the effect of rootstocks on grape production, quality and antioxidant capacity of ‘Niagara Rosada’ grape in two productive cycles. The work was developed in Jundiaí-SP, Brazil (26° 06’ S, 46° 55’ W and an average altitude of 745 m). The experimental design was in randomized blocks with subdivided plots, the plots being represented by the rootstocks and the subplots by the production cycles, with four replications, each consisting of 6 plants. The treatments consisted of a combination of ‘IAC 313 Tropical’, ‘IAC 572 Jales’, ‘IAC 571-6 Jundiaí’, ‘IAC 766 Campinas’ and ‘106-8 Mgt’ as rootstocks and ‘Niagara Rosada’ as graft, and the production cycles were 2013 and 2014. The number of bunches, production and productivity of the vines, the physical characteristics of bunches, berries and stalks and the physicochemical composition of the must (soluble solids content, titratable acidity, pH and the relation soluble solids/titratable acidity) were evaluated in production cycles of 2013 and 2014). The content of chlorophylls, anthocyanins, carotenoids, flavonoids and total phenolic compounds and the antioxidant activity of grapes were also evaluated in grape berries. The rootstocks did not influence the production and physical quality of ‘Niagara Rosada’ grapes. As for the chemical characteristics, rootstocks only had an effect on solids content, and ‘IAC 766’ and ‘106-8 Mgt’ rootstocks promoted higher values of this characteristic. Likewise, the total phenolic compounds and the antioxidant activity of the grapes were not influenced by the studied rootstocks. The vines in 2013 presented higher production and better physical characteristics of the grapes, however, the soluble solids content in this cycle was lower than in 2014.

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Abtract In Brazil, the producers have changed used rootstocks to get more vigor to scion. Rootstocks change the distribution of bud fruitfulness over grapevine shoots and the expression of the bud fruitfulness into fruit yield. Hence, these modification could alter ideal pruning length. In this way, it was evaluated bud fruitfulness, fruit yield and quality of ‘Niagara Rosada’ grapevine grafted onto rootstocks: ‘IAC 766’, ‘IAC 572’, ‘IAC 313’, ‘IAC 571-6’, and ‘Riparia do Traviu’, which ‘IAC 766’ is the most used rootstock in São Paulo State, nowadays. The evaluations were performed over three crop seasons, in a vineyard located in Louveira, SP. Two evaluations were performed in Brazilian traditional season, and one crop pruning was performed in Brazilian summer, called “off-season”. In traditional seasons, the bud fruitfulness was evaluated from the first to fourth bud in 2014 and to the fifth in 2015. In the off-season, bud fruitfulness was evaluated from the fifth to eighth bud. Fruit yield and quality were also evaluated over the three production cycles. Bud fruitfulness of ‘Niagara Rosada’ grafted onto the evaluated rootstocks showed that this characteristic was more affected by the environmental conditions, confirmed due to alteration of bud fruitfulness through production cycles. Additionally, no effect of rootstock was observed on fruit yield, and quality of ‘Niagara Rosada’. Only isolated variations were detected, and these are not enough to confirm the influence of rootstocks on scion of ‘Niagara Rosada’. Although no effect of rootstocks on bud fruitfulness, fruit yield and quality has been observed in the evaluated conditions, all rootstocks are recommended to be used in combination with ‘Niagara Rosada’.

With the growth of new areas of grapevine planting in Brazil and other tropical countries, the rootstocks play an important role in the implantation of new areas and adaptation of cultivars. The development of new materials has increased productivity per area and even the final quality of the grapes. One of the problems in the propagation of rootstocks grapevine is the natural dormancy present in several species. We aimed to assess the stratification time's initial development and feasibility of grapevines rootstocks stem cuttings on field conditions. Two experiments were carried out. In the experiment of initial development of rootstocks grapevine, were used varieties: '