The effects of plant and animal-derived aminoacid and humic acid-based biostimulants on yield and quality in the wine grape

In recent years, biostimulants, which are of great importance in sustainable viticulture, are generally applied to plants at low doses via foliar application to regulate or enhance plant physiological processes, improve product vitality, yield, and quality, and overcome stress conditions. This study was conducted in Antalya, Turkey, in 2019 and 2020, to determine the effects of different biostimulant applications on yield and quality parameters in the Öküzgözü grape variety. The experiment was set up in a randomized block design with three replications. The treatments encompassed humic acid, plant-derived amino acids, animal-derived amino acids, and their combinations (HU+PAA and HU+AAA), with a control group receiving tap water. It is evident from the analysis of two-year averages that biostimulant applications have a considerable impact on the morphological characteristics of berries, including size, as well as on cluster characteristics and yield per cluster. The biochemical quality criteria also demonstrate a clear response to biostimulant application. The highest yield (13.20 kg·plant^-1), cluster weight (505.5 g), and 100-berry weight (608.4 g) were obtained with the HU+PAA combination. The application of HU+AAA resulted in a significant increase in anthocyanin content (1463 mg·100 g ^-1FW), while the application of plant amino acids led to a notable increase in L-ascorbic acid content (8.60 mg·100 g ^-1 FW). Statistically significant differences were not observed between the treatments in terms of phenolic compound and flavanol contents. The creation of a heat map was informed by the data that was obtained, and principal component analysis (PCA) was subsequently performed. The findings indicated that biostimulant applications, particularly when used in combination, are efficacious in enhancing both yield and quality in the Öküzgözü grape variety.