Guru, S.K.Tiwari, Deeksha2019-11-062019-11-062019-09http://krishikosh.egranth.ac.in/handle/1/5810134509Zinc (Zn) is an essential micronutrient in biological metabolism required for normal growth and development of plants and humans. In plants, zinc plays a crucial role in enzymatically driven metabolism and it also contributes toward gene expression and stress tolerance. Similarly, in humans it affects multiple aspects of the immune system and is required for normal development and proper function of cell mediating immunity. Zinc deficiency is among the top five micronutrient deficiencies and severely affects one-third of the world’s population, especially rural communities. The main reason for this deficiency is the intake of food low in zinc content. Wheat is the major staple food for world population and is inherently low in zinc concentration. Biofortification of wheat grains with zinc can help to combat this micronutrient deficiency to a large extent. A research investigation was carried out to evaluate the effects of zinc application on yield and nutritional quality of wheat grains. The investigation was carried out in N. E. B. Crop Research Centre, Pantnagar during Rabi season 2018-19. Wheat variety PBW 343 was used as the experimental material. Zinc was applied at four concentrations (0.25, 0.50. 0.75 and 1.0% ZnSO4) and at three stages i.e. S1 (one spray of ZnSO4 at 30 DAE), S2 (two sprays of ZnSO4 one each at 30 and 45 DAE) and S3 (three sprays of ZnSO4 one each at 30, 45 and 60 DAE). Zinc application had a promoting effect on LAI, TDM, panicles/m2, spikelet number/m2, biological yield, grain yield, straw yield and the maximum increase in biolo0gical and grain yield was recorded with three sprays of 0.75% ZnSO4. Harvest index and test weight were unaffected by zinc application. Biochemical analysis revealed that total chlorophyll content, activity of SOD and Carbonic anhydrase increased with zinc application. Zinc content of grains and straw also increased with application of zinc giving a maximum value with three sprays of 0.75% ZnSO4. Iron content of grains and straw also increased with zinc application at 1.0% ZnSO4. On the other hand a negative effect of zinc application was found on phytic acid and phosphorus content of grains and molar phytic acid: zinc ratio and the maximum decrease were found with 1.00% ZnSO4. Protein content also increased significantly with zinc application giving maximum protein content with 0.75% ZnSO4. The study revealed three sprays of 0.75% ZnSO4 one each at 30, 45 and 60 DAE was most effective for increasing the grain yield as well as the nutritional quality of wheat grains. However remobilization of zinc from leaves to grains is a mechanism which should be considered for further study to efficiently utilize the applied zinc.ennullThesis