Determination of Critical Levels of Petiole Nutrient Contents for Thompson Seedless Grape (Vitis Vinifera L.)

An attempt was made to determine the critical levels of petiole NO₃-N, total N, P, K, Ca and Mg for fruit yield in Thompson Seedless grape employing the Cates and Nelson's procedure in a situation where the quadratic response curve was possible only with petiole K contents. Petiole N0₃-N, total N, P, K, Ca and Mg contents of 0.263, 1.54, 0.32, 2.24, 0.96 and 0.325 per cent on dry weight basis were found to be critical with yield determinations of 6.6, 10.1, 5.7, 19.5, 4.9 and 11.4 per cent respectively.