Response of Balady Lime Tree Growth and Productivity to Rootstock Type and NPK Nutrient Levels under Upper Egypt Conditions. A- Response of Balady Lime Tree Growth to Rootstock Type and NPK Nutrient Levels.

Experimental treatments were carried out during (2017-2020) seasons respectively, on 10-year- old Balady lime (C. aurantifolia L.). Thirty six-Balady lime tree- budded on 3 citrus stocks: A1) Troyer citrange; A2) C. volkameriana and A3) C. macrophylla'' Factor A'' carefully selected for vigorous growth. Trees grown in sandy soil in a private orchard at Sahel- Sleem district, Assiut Governorate under drip irrigation. Trees seasonally received three NPK, nutrient fertilizer levels: ''Factor B'': B1:  NPK (3:1:2) ''control''. B2: NPK (2:1:1). B3: NPK (3:2:2) and B4: NPK (4:3:3) for every rootstock alone. Experimental treatments resulted that both Citrus: Macrophylla or Volkamer lemon stocks expressed a superiority with positive effect on most  tree growth parameters as compared to Troyer citrange stock during studied seasons. Moreover, NPK nutrient levels B2, B3 or B4 significantly gave the highest values for the previous Balady lime parameters when compared to NPK B1 (the control) during the experimental seasons. In spite of, Troyer citrange, Citrus macrophylla or Volkamer lemon stocks plus NPK nutrient levels B3 or B4 statistically improved Balady lime parameters as compared to the same stocks plus NPK nutrient levels B1 or B2. Finally, it can be concluded that, both Citrus macrophylla or Volkamer lemon stocks plus NPK nutrient levels B3 or B4 were the best during the studied seasons.