This experiment was carried out in a Zn-deficient calcareous soil to study the effects of Zn deficiency on shoot dry weight, shoot content, and concentration of Zn, and also to identify new sources of Zn efficiency for further improvement of Zn efficiency with (+Zn = application of 5 mg Zn/kg soil) and without Zn supply (-Zn = non-application of zinc) on 50 durum wheat genotypes for 45 days. Variance analysis for shoot dry matter, shoot Zn concentration, shoot Zn content, and Zn utilization efficiency revealed that these traits were significantly (P< 0.01) affected by Zn application and durum wheat genotypes. Results revealed that dry weight of shoot and shoot Zn accumulation were considerably improved by Zn fertilizers. Furthermore, there was a considerable genetic variation in the expression of Zn deficiency symptoms (slight to severe), Zn efficiency (49-100%), shoot Zn concentration (7.1-20.1 and 10.4-33.1 mg Zn/kg dry weight under Zn deficient and sufficient, respectively), shoot Zn content (0.31-1.47 and 0.7-2.9 µg/plant under Zn deficient and sufficient, respectively), and Zn utilization efficiency (59.2-139.1 and 34.3-94.0 g dry weight/µg Zn under Zn deficient and sufficient, respectively) within durum wheat genotypes. In general, the presence of lines (AAZ, 4025, 45868, 45558 and Azarbayjan) with greater Zn efficiency than Zn efficient durum wheat cultivars (Ege- 88, Aydin-93 and Akcakale-2000) indicates that the new lines can be used to improve current levels of Zn efficiency in durum wheat genotypes.
