The effects of seaweed practices on yield and quality criteria in round seedless (Vitis vinifera L.) grape variety

This study was carried out on the Round Seedless grape variety grown in the Viticulture Application and Research Center Directorate in Siirt University Kezer Campus. Three different times and four different doses [control (0 ppm), 1st application (1000 ppm before flowering), 2nd application (1000 ppm before flowering + 1000 ppm after flowering), 3rd application (1000 ppm before flowering + after flowering) 1000 ppm + veraison 1000 ppm)] applied liquid seaweed on phenological stages and its effects on yield, berry and must parameters were compared. When the phenological periods were compared with the control; It was determined that the first application took the full flowering phase three days earlier and the veraison phase six days earlier. The Total Effective Temperature (TET) value between full bloom and veraison was determined to be between 659.78-819.98 gd, and it was determined that the first application shortened the vegetation period compared to the control, while the other two applications extended the vegetation period. When the data obtained in terms of yield parameters were compared with the control, the average cluster weight per vine was 12.51% in the 1st application; an increase of 19.57% in the 2nd application and 7.63% in the 3rd application; grape yield per vine was 22.10% in the first application; It was determined that it caused an increase of 25.97% in the 2nd application and 18.84% in the 3rd application. In addition, the amount of leaf chlorophyll was 0.80% in the first application; An increase of 2.52% in the 2nd application and 0.58% in the 3rd application; the average leaf weight was 9.80% in the first application; It was determined that it caused an increase of 19.89% in the 2nd application and 22.69% in the 3rd application. The average number of clusters per vine ranges from 46.87 to 48.56; cluster width between 14.58-16.09 cm; the pot length is between 24.12-25.48 cm; It was determined that the berry width was between 14.28-15.49 mm and the berry length was between 14.55-15.65 mm. When the data obtained in terms of must parameters were compared with the control; 1st application in Total Soluble Solid Contents (TSSC) amount is 1.92%; 2nd application decreased by 6.55% and 3rd application by 10,64%; 1st application in maturity index 5.19%; 2nd application decreased by 11.05% and 3rd application decreased by 12.41%; 1st application 8.51% in total phenolic compound amount; 2nd application increased 12.05% and 3rd application increased 12.13%; in the total amount of flavonoids, the 1st application was 0.32%; It was determined that the 2nd application caused an increase of 2.56% and the 3rd application caused an increase of 17.44%. pH value is between 4.05-4.26; must yield is between 1,563.33 and 1,873.33 mL; the amount of density is between 1.03-1.32g/mL; the total acidity amount was found to be between 3.25-3.41 g/L. L* value is between 22.50-25.01; a* value is between -3.70 and -2.48; The b* value was determined between 9.49-12.11. The chroma value is between 10.18-12.36; Hue angle was determined between 101.56-111.32. In the light of all the evaluations, it was concluded that the most effective of the liquid seaweed applications applied in three different times and four different doses in terms of yield and quality criteria is the 2nd application (1000 ppm before flowering + 1000 ppm after flowering). Liquid seaweed application is scientifically important as it is the first study conducted on the Round Seedless grape variety grown in Siirt ecology.