ROLE OF ZINC FERTILIZATION IN INCREASING YIELD QUANTITY an‎d QUALITY OF WHEAT

Two field experiments were carried out to study the response of two wheat cultivars, bread wheat cv. Abu-Ghraib 3 and durum wheat cv. Doar 85 to zinc fertilization and its effect in grain yield, biological yield, protein, zinc and phosphorus contents in grains. In the first experiment Zinc was applied to the soil, at levels of 4.0 and 8.0 kg Zn.ha-1 and control treatment (without Zinc). The Zinc was added in two forms, mineral form (ZnSO4.7H2O) and chilating form (Zn-DTPA). In the second experiment Zinc was applied as a foliar application. Zinc levels were 0.4 and 0.8 kg Zn.ha-1 and control treatment (spraying with water only). The results showed that the grain yield and biological yield increased significantly compared with control treatment by soil application of 8.0 kg Zn.ha-1. The rate of increases in grain yield was 26.4 and 38.5% and biological yield by 19.0 and 36.9 % for cultivars abu-ghraib and doar 85, respectively. Also grain yield and biological yield increased significantly compared with control treatment by foliar application of 0.8 kg Zn.ha-1. The rate of increases in grain yield were 11.8 and 32.4% and biological yield increased by 9.9 and 28.2% for cultivars abu-ghraib 3 and doar 85 respectively. Also protein content in grains of two cultivars increased significantly as result of zinc soil application at 8.0 kg Zn ha-1 also when zinc was applied at 0.8 kg Zn.ha-1. The rate of increases were 15.4 and 9.7% when zinc applied to soil while the rate of increases were 14.8 and 6.2% when zinc applied as a foliar application for abu-ghraib 3 and doar 85 cultivars respectively for the two zinc sources. Zinc content in grain of two cultivars increased significantly as result of zinc application at level of 8.0 kg. ha-1. In addition, application of zinc at level of 8.0 kg. ha-1 , phosphorus content in grain decreased by 5.1 and 5.3 for cultivars abu-ghraib 3 and doar 85, respectively. Also, when zinc was applied at 0.8 kg Zn.ha-1 as a foliar application zinc content in grain increased for two cultivars while, phosphorus content in grain decreased by 6.9 and 9.3 for both cultivars abu-ghraib 3 and doar 85, respectively. In general, soil application of zinc at level of 8.0 kg ha-1 from two sources, inorganic and organic form is the better response in increases grain yield, biological yield, grain protein content, zinc content for the two cultivars.