The impact of abscisic acid application on grape quality attributes at harvest and post-harvest period

Table grape varieties do not reach commercially acceptable colour levels in some growing seasons in viticultural areas. This situation has led to the consideration of applications that can enhance grape coloration. The study examined the effects of abscisic acid on 'Spil Karası' grape clusters and berries at harvest time and after harvest. A single application of 400 mg L⁻¹ ABA was made during the veraison period to evaluate its effects on berry coloration and post-harvest quality. Cluster weight losses were measured on days 7 and 15, while titratable acidity (TA), Brix, and fruit and rachis colour analyses were conducted on days 15 and 30 after harvest. The research results indicated that the application of ABA (abscisic acid) was not effective in terms of the parameters examined during harvest time analyses. The weight loss due to ABA application on the 15th day was 1.1% higher compared to the control. The ABA treatment group exhibited higher Lightness (L) values compared to the control group 30 days after harvest. The control group recorded the lowest Hue values at the same time point. However, this group displayed a high Chroma value. Conversely, the ABA treatment group showed a low Chroma (C) value during the same analysis period. Also the lowest L values were determined in ABA treatment and control groups 30 days after harvest in rachis.