Foliar applied zinc on different growth stages to improves the growth, yield, quality and kernel bio-fortification of fine rice

Zinc (Zn) is an essential nutrient required for plants growth and development, nonetheless, Zn deficiency is continuously increasing in our soils which is decreasing crop production. Further, the crops grown on Zn-deficient soils also contains a low amount of Zn which is also a major reason for Zn deficiency in humans. So, it is mandatory to supply the Zn to fulfil the crop needs with a corresponding increase in grain Zn. Thus, this study determined the impact of different rates of foliar applied Zn at different growth stages on the growth, yield, quality, and Zn bio-fortification of fine rice. The study comprised foliar application of distilled water (control), foliar applied Zn @ 0.5% at stem elongation stage + booting stage, foliar applied Zn @ 1.0% at stem elongation stage + booting stage, foliar applied Zn @ 0.5% at booting stage and milking stage, foliar applied Zn @ 1.0% at booting stage and milking stage, foliar applied Zn @ 0.5% at milking stage + dough stage and applied Zn @ 1.0% at milking stage + dough stage. The results indicated Zn applied different growth stages significantly improved, productivity and Zn bio-fortification of rice crop. The maximum LAI, LAD, CGR, fertile tillers (363.17 and 372.17), 1000 KW (25.50 g and 25.61 g), kernel yield (5.45 t ha-1 and 5.44 t ha-1), biomass yield (14.22 t ha-1 and 14.26 t ha-1) HI, chlorophyll concentration (1.60 mg/g FW and 1.52 mg/g FW), relative water content (92.33% and 90.11%), and antioxidant activities were observed with foliar applied Zn (0.5%) at booting and milking stage and lowest values of all these traits were observed in control. Likewise, the maximum kernel protein (10.55% and 10.88%), amylose (27.85% and 26.18%), kernel length (6.54 mm and 6.68 mm) and width (2.37 mm and 2.77 mm), and grain Zn concentration (32.22 mg kg-1 and 30.21 mg kg-1) was recorded with Zn (0.5%) at the booting and milking stage, and minimum kernel protein, amylose, kernel length, and width, and grain Zn concentration was noted in control. The current study findings suggested that foliar-applied Zn (0.5%) at the booting and milking stage could be an important practice to get better productivity, quality, and grain Zn bio-fortification of rice in semi-arid conditions.