Screening of Rice Cultivars for their Zinc Biofortification Potential in Inceptisols

Twenty six rice cultivars were evaluated in field experiment for their native zinc (Zn) contents as well as response to Zn applied through soil (20 kg Zn ha⁻¹) with or without foliar spraying (0.5% ZnSO₄.7H₂O solution). Results revealed that increased harvest index (HI) of rice also corroborated with higher Zn content in grains upon its basal application as well as foliar spraying. The concentration of native Zn in rice grains was higher in aromatics (27.8 mg kg⁻¹) followed by locals (26.3 mg kg⁻¹), HYVs (23.0 mg kg⁻¹) and hybrids (22.0 mg kg⁻¹). Foliar application of Zn was effective than soil application regarding Znbiofortification of rice. Two foliar spraying of Zn along with basal application increased the grain and straw Zn concentration up to two to three folds. Transfer coefficient of Zn from shoot to grains, on the other hand, recorded an increase with Zn application in hybrids and locals but decreased in HYVs and aromatic cultivars. Zinc efficiency was higher in aromatic cultivars followed by HYVs, hybrids and locals. Transfer coefficient of Zn within the rice cultivars might be related to their physiological activities, which possibly reduced the translocation of Zn from shoot to grains in HYVs and aromatic cultivars. Increased Zn efficiency of aromatic cultivar might be related to its adaptive mechanisms to tolerate Zn deficiency stress.