‘Italia’ grape is one of the most important table grape cultivars grown worldwide. Gray mold, caused by Botrytis cinerea Pers. Fr., is one of the most important causes of postharvest decay of table grapes, and the control of this disease is very difficult because postharvest treatments with synthetic fungicides are not allowed in many countries. The objective of this study was to compare different types of pads releasing different doses of SO₂ during cold storage to control gray mold in ‘Italia’ table grapes grown under subtropical conditions. Grape bunches were harvested from a commercial field trained on an overhead trellis located at Cambira, state of Parana (PR), South Brazil. The grapes were packed into carton boxes (capacity, 4.5 kg) and subjected to the following SO₂ pad treatments (Uvasys^®, Cape Town, South Africa) under cold storage (1.0 ± 1 °C) for 50 days: (i) Control; (ii) SO₂ slow release pad; (iii) SO₂ dual release pad; (iv) SO₂ dual release–fast reduced pad; (v) SO₂ slow release pad with grapes inoculated with B. cinerea suspension; (vi) SO₂ dual release pad with grapes inoculated with B. cinerea suspension; and (vii) SO₂ dual release-fast reduced pad with grapes inoculated with B. cinerea suspension. After cold storage, the grape boxes were maintained for 7 days at room temperature (25 °C). The incidence of gray mold on the grapes, firmness, shattered berries, stem browning, as well as other physicochemical variables, such as bunch mass, bunch mass loss, skin color, soluble solids (SS), titratable acidity (TA) and SS/TA were evaluated. Both SO₂ dual release pads were highly efficient in preventing the incidence of gray mold in ‘Italia’ grapes packed in clamshells during the 50-day period of cold storage and at room temperature, even with Botrytis-inoculated berries. The SO₂ slow release pad showed lower efficiency, but was higher than the control. The SO₂ dual release pad treatments provided the best results with respect to stem browning scores (fresh and green stems) during cold storage, and no differences were observed among the treatments with respect to the other physicochemical evaluations.

In colored table grapes, the anthocyanin contents are inhibited by the high temperature during ripening and berries suffer a lack of skin color, thus affecting their market value. In order to overcome this issue, a research study was planned to evaluate the influence of (S)-cis-abscisic acid (S-ABA) on rates of anthocyanin accumulation in table grapes when applied at different timings of ripening, and to quantify the gradual increase of berry color. The study was conducted in a commercial vineyard of ‘Benitaka’ table grapes (Vitis vinifera L.), grown under double annual cropping system in a subtropical area. The trials were carried out during two consecutive seasons (i.e., summer season of 2015 and off-season of 2016). The treatments used for the experiments contained 400 mg L⁻¹ S-ABA applied at different timings of veraison (the onset of ripening), as follows: control (with no application); at pre-veraison (PRV); at veraison (V); and at post-veraison (POV). For all S-ABA treatments, a second application was performed 10 days after the first application. Berries were analyzed for weekly and daily anthocyanin accumulations, weekly and daily color index development (CIRG), total soluble solids (TSS) content, titratable acidity (TA), and maturation index (TSS/TA). Grapes subjected to exogenous application of S-ABA at any time of veraison, especially at PRV or at V, significantly increased the anthocyanin accumulation as well as berry color index development. Other chemical properties of grapes (i.e., TSS, TA, and TSS/TA evolution) were not affected by the use of S-ABA and followed a predictable pattern in relation to days of berries ripening.

‘BRS Vitoria’ (Vitis spp.) is a novel hybrid seedless table grape recommended for cultivation in tropical and subtropical areas, especially for overseas export. The main postharvest disease of this cultivar is botrytis or gray mold (Botrytis cinerea), which occurs even under low temperatures in cold chambers. Sulfur dioxide (SO₂) release pads have been used to control this disease under cold storage, but some grape cultivars are sensitive to certain levels of this compound. The objective of this work was to evaluate different types of SO₂ generator pads in order to prevent the incidence of gray mold of ‘BRS Vitoria’ seedless grape, as well to avoid other grape injuries during cold storage. Grape bunches were harvested when fully ripened (16°Brix) from a commercial field trained on overhead trellis and located at Marialva, state of Parana (PR) (South Brazil). Grapes were packed into carton boxes and subjected to the following SO₂ pad treatments (Uvasys^®, Cape Town, South Africa) in a cold chamber (2 °C): (a) control; (b) SO₂ slow release pad; (c) SO₂ dual release pad; (d) SO₂ dual release–fast reduced pad; (e) SO₂ slow release pad with grapes inoculated with B. cinerea; (f) SO₂ dual release pad with grapes inoculated with B. cinerea; and (g) SO₂ dual release–fast reduced pad with grapes inoculated with B. cinerea. After a 50-day cold chamber period, the grape boxes were kept for 7 days at room temperature at 25 °C. A randomized design was used with seven treatments and four replications, with five bunches per plot. The incidence of gray mold on grapes was evaluated after the 50-day cold storage and after the 7-days-at-room-temperature periods, as well other grape physicochemical variables, such as shattered berries, stem browning, bunch mass, bunch mass loss, skin color, soluble solids (SS), titratable acidity (TA), and SS/TA. The dual release pads were more efficient in preventing the incidence of gray mold and mass loss in ‘BRS Vitoria’ seedless grapes than the slow release pads in both storage periods. The incidence of shattered berries was lower when any type SO₂ pad was used during cold storage, and no effects were observed on stem browning, firmness, or berry skin color of ‘BRS Vitoria’ grapes.

‘BRS Isis’ is a new hybrid seedless table grape tolerant to downy mildew with a good adaptation to the tropical and subtropical climates. Gray mold, caused by Botrytis cinerea Pers. ex Fr. is known as the most important postharvest mold in table grapes, causing extensive losses worldwide. As the postharvest behavior of ‘BRS Isis’ is still unknown, the objective of this work was to evaluate the postharvest preservation and B. cinerea mold control of this new grape cultivar, grown under the double-cropping a year system. Grape bunches were purchased from a field of ‘BRS Isis’ seedless table grapes trained on overhead trellises located at Marialva, state of Parana (South Brazil). Grapes were subjected to the following treatments in a cold room at 1 ± 1 °C: (i) Control; (ii) SO₂-generating pad; (iii) control with bunches inoculated with the pathogen suspension; (iv) SO₂-generating pad with bunches inoculated with the pathogen suspension. The completely randomized experimental design was used with four treatments, each including five replicates. The incidence of gray mold and other physicochemical variables, including bunch mass loss, shattered berries, skin color index, soluble solids (SS), titratable acidity (TA), and SS/TA ratio of grapes, were evaluated at 50 days after the beginning of cold storage and at seven days at room temperature (22 ± 2 °C). The ‘BRS Isis’ seedless grape, packaged with SO₂-generating pads and plastic liners, has a high potential to be preserved for long periods under cold storage, at least for 50 days, keeping very low natural incidence of gray mold, mass loss, and shattered berries.