Introduction: Zinc (Zn) as an essential micronutrient and cytokinin as phytohormone not only regulate plant growth but also play fundamental roles in plant tolerance against drought stress. Understating the function and the role of cytokinin in combined with an essential micronutrient, Zn, could improve the choice of a sustainable strategy for improvement of plant drought stress. The objective of this field research was to determine the effect of postflowering foliar application of ZnSO4 and 6-benzylaminopurine (6-BAP) on grain yield and quality of winter wheat under water deficit condition. Methods: Experiments were conducted under filed condition. Drought was imposed by with holding irrigation at the beginning of flowering till the signs of temporary wilting/leaf rolling appeared, after which all plots were irrigated to field capacity. The foliar treatment consisted of (1) foliar application of water, as control treatment; (2) foliar application of 10 g ha-1 6-BAP; (3) Foliar application of 20 g ha-1 6-BAP; (4) Foliar application of 10 g ha-1 6-BAP plus foliar application of 6 kg ha-1 ZnSO4 solution and (5) foliar application of 10 g ha- 1 6-BAP plus foliar application of 6 kg ha-1 ZnSO4 solution 2 days before drought imposition. Data were collected on grain and straw yield, yield attributes, harvest index, flag leaf fresh matter and dry matter weight, TaCKX6-D1 expression, phytic acid content in grains, mycorrhiza colonization rate and succinate dehydrogenase (SD) activity. Results: According to ANOVA, the factor ‘Zn’ significantly affected leaf relative water content (p < 0.001). Relative water content for plants foliar applied with 6-BAP was not statistically significant.
