SEASONAL VARIATIONS IN NUTRIENT CONCENTRATION OF JUICE AND SKIN OF TEN GRAPE (VITIS VINIFERA L.) GENOTYPES

The nutrient status of grape berries is not only of interest to the viticulturists but also to oenologists because of their impact on juice nutritional value. The aim of the study was to determine the total potassium, total calcium and nitrogen in the berry skin and juice of ten grape genotypes grown in northwestern India. The total potassium, calcium and nitrogen content in the grape genotypes varied significantly in berry skin, juice and evaluation years. Among the grape genotypes maximum calcium was recorded in Punjab MACS Purple in skin ( 0.497 mg/l) and juice (0.403mg/l) at ripened stage. The maximum potassium was also at ripened stage in the skin of H-27(2.800%) and juice of Perlette( 1.610%). However, nitrogen content was maximum in the skin of Merlot(0.336mg/l) and juice of Perlette( 0.184%) at green stage. This study suggests that the selected grape genotypes are the potential sources of essential mineral nutrients.