Screening of cash crops to tolerate and grow under low levels of micronutrients is important issue in the plant breeding programs. Thus, the study screened the tolerance of 50 wheat genotypes to zinc (Zn) deficiency in the calcareous soil. The Zn treatment was carried out with application of 5 mg kg-1 (+Zn) and without (-Zn) to the collected soils with initial Zn extractable of 0.5 mg Zn kg-1 soil. The results revealed that the supplementary application significantly increased shoot dry matter, shoot Zn concentration and shoot Zn content compared to the without Zn application (control), but Zn utilization decreased under Zn application. There was considerable genetic variation in Zn efficiency (55 - 118 %), shoot Zn concentration (11.8 - 27.0 and 14.3 - 39.6 mg kg-1 DM under deficient and sufficient Zn, respectively), shoot Zn content (0.56 - 2.02 and 0.90 - 2.83 µg plant-1 - 2.83 µg plant-1 Zn utilization efficiency (39 - 87.2 and 31.2 - 71.5 mg DM µg-1 Zn under deficient and sufficient Zn, respectively) within wheat genotypes. Cluster analysis based on Zn efficiency, and shoot dry matter at deficient and adequate Zn conditions classified the genotypes into four clusters. Over the two conditions, the most Znefficient and Zn-unefficient genotypes were ‘Ankara-98’ and ‘Altintoprak-98’ and ‘Pg"S’ and ‘Zarin’, respectively. Most durum genotypes had a greater Zn efficiency than modern bread wheat genotypes, therefore these genotypes could be effectively used to breed the new cultivars with high Zn efficiency for calcareous soils.
