A field experiment was conducted at the Department of Rice, Tamil Nadu Agricultural University, Coimbatore-3 during Kharif season, 2017. The objective of the experiment was to study the influence of Zinc nutrition on growth, physiology, ZUE, yield and grain Zn content of rice genotypes at two stages of crop. The experiment was laid out in a factorial randomized block design with three replications. The results of the field study revealed the maximum total tillers per plant were observed in the rice genotype IR93354:19-B-12-21-9-1RGA-2RGA-1-B under 0.5% ZnSO4 condition at the grain filling stage. However the higher total dry matter production recorded in the genotype IR15M1266 under 0.5% ZnSO4 treatment. Regarding zinc use efficiency indices, the maximum zinc use efficiency (42.2%) was observed in the foliar application of 0.5% ZnSO4 in rice genotype IR14M117 followed by BPT5204 (39.0%). The higher spikelet fertility was observed in BPT5204 (98.2%) under foliar application of 0.5% ZnSO4 was followed by Kalanamak (97.3%) on par with Chittmutyalu (97.2%) was under 0.5% ZnSO4 application. The treatment 0.5% ZnSO4 had recorded higher grain yield (8870.0 kg/ha) in IR95097:3-B-16-11-4-GBS which was on par with IR14M124 (8800 kg/ ha). To conclude, when foliar sprayed with zinc sources such as 0.5% ZnSO4 and 0.5 % Zn EDTA at boot leaf and grain filling stage in rice genotypes like IR15M1003, IR95097:3-B-16-11-4-GBS, IR95040:12-B-3-10-GBS, IR15M1341 and IR95097:4-B-2-18-8-GBS showed significant changes in growth, physiology and zinc grain content.
Key words : Rice, Zinc sulphate, foliar application, zinc EDTA, grain filling stage