Soil and foliar zinc application techniques influence the productivity, zinc concentration, and protein content in the grains of bread wheat varieties

Micronutrient zinc (Zn) is crucial for both humans and plants. To improve the micronutrient concentration in the grains of food crops, biofortification has already been established as one of the best approaches across the globe. The current study was carried out to assess Zn enrichment in a few common wheat varieties using different Zn delivery techniques. The following treatments were applied: T1: control (without Zn), T2: Soil application of 4 kg Zn ha-1 at final land preparation, T3: Foliar application of a 0.5% Zn solution (ZnSO4 x7H2O) at both tillering and booting stages, and T4: soil application of 2 kg Zn ha-1 at final land preparation + foliar application of a 0.2% Zn solution (ZnSO4 x7H2O) at both tillering and booting stages. All treatments were arranged in a split-plot design and repeated three times The findings of the study revealed that the various Zn application techniques had an impact on the Zn concentration in grains significantly, ranging from 23.9 to 32.2 µg g-1 across the varieties, with an average of 28.2 µg g-1 in the control. Among these various application techniques, the soil + foliar application induced the highest response of the Zn concentration in the grains ranging from 33.7 to 37.60 µg g-1. The average protein content (%) in the grains of all wheat varieties varied by 1.21, 1.47, and 1.51%, respectively, as a result of the use of the different Zn application methods. Considering the Zn-use efficiency (%), the most Zn-efficient wheat variety was BARI Gom 28, followed by BARI Gom 26, Binagom-1, BARI Gom 25, and BARI Gom 29. In the case of grain yield, wheat variety BARI Gom 26 (4.15 t ha-1) performed the best in the soil + foliar Zn application. The soil + foliar application method outperformed the other application techniques regarding the Zn concentration, yield, and protein content in the grain.