Abstract

                                A pot culture experiment was conducted at Tamil Nadu Agricultural University, Coimbatore to establish the genotypic divergence in per cent zinc (Zn) derived from fertilizer (% Zndff) or from soil (% Zndfs) and on zinc uptake of two rice genotypes Zn -efficient Norungan and Zn –inefficient PMK 3. To assess the partitioning of Zn in the shoot and root of the genotypes, radiotracer technique was employed, in which graded levels of Zn (0.0, 12.5, 25.0, 37.5 and 50.0 kg ha-1 of ZnSO4) as 65Zn labeled ZnSO4 were applied. Per cent Zndff showed an increase by 50 % for Zn-inefficient PMK 3 than that for Norungan while reverse was the trend for % Zndfs implying the fact that Zn inefficient genotypes have the ability to use only readily available sources of Zn. Zinc uptake from fertilizer increased with increasing dose of applied zinc for PMK 3 while in Norungan it showed a peak at 25 kg ha-1 of ZnSO4 and thereafter it declined. Irrespective of the sources of zinc, root zinc accumulation was higher in PMK 3 than that in Norungan. The Zn-efficient genotype Norungan had better translocation of Zn from root to shoot than PMK 3.

Key words : Rice genotypes, Zn – efficient, Zn uptake.