Influence of Different Sources and Methods of Potassium Application on the Quality of Grapes Cv. Sharad Seedless ( Vitis vinifera L.)

Potassium is often considered as the quality element for crop production. Grapevine is one of the most potassium-friendly plants that has a better ability to utilize soil potassium. Grape berries are a strong sink for potassium, particularly during ripening. To ascertain the influence of the combined application of different sources and methods of potassium application on the quality of grape cv. Sharad Seedless, an experiment was conducted at Indian Institute of Horticultural Research, Bengaluru during two consecutive years, viz. 2016–17 and 2017–18 with three different sources of potassium fertilizers (SOP, KNO₃ and 19 : 19 : 19), and two methods of application (soil application and fertigation). Pooled analysis revealed that among the treatments, grapevines treated with sulphate of potash as 60% through fertigation and 40% through soil registered the highest total soluble solids (22.16° ºBrix), Brix : acid (36.38), total sugars (19.66%) and least titratable acidity (0.61%) in berries. With regards to biochemical constituents like total phenols, total flavonoids and anthocyanins, significantly highest value was observed in vines treated with 100% SOP through fertigation.