Physiological aspects of enhancing grain zinc content and its bioavailability in winter wheat (Triticum aestivum L.) through foliar application of zinc
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Date
2022-06
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G. B. Pant University of Agriculture and Technology, Pantnagar
Abstract
Zinc deficiency stems from dietary malnutrition. Wheat grains are inherently low in zinc concentration as well as bioavailability primarily on account of being cultivated in soils with poor zinc phyto-availability. Wheat-based products account for provisioning of 50% daily dietary zinc intake. Therefore, there is a need to biofortify the wheat grains with Zn. The present investigation was carried out to study the physiological aspects of enhancing grain zinc content and its bioavailability in wheat cultivar PBW 343. The field investigation was carried out in two successive winter seasons (2018-19 and 2019-20) at the Dr N. E. Borlaug Crop Research Center, Pantnagar, India. A pot culture experiment was also carried out to study the effect of chelators on grain zinc and its bioavailability. Five different concentrations of zinc 0, 567.5, 1135, 1702.5 and 2270 ppm zinc were used in the field study which were sprayed at three different stages viz. 30, 45 and 60DAE. Two different Zn concentrations 1135ppm Zn and 1702.5ppm Zn along with three chelators 0.025% Methionine, 0.02% Histidine and 0.1% Citric acid were used in the pot culture experiment. The results show that Zn application had promoting effect on growth, yield and yield related attributes. It also increased chlorophyll content as well as zinc associated enzyme activities in the flag leaf. The maximum increase in grain yield was recorded at 1702.5ppm of Zn. Under the field conditions, three sprays of 2270ppm Zn resulted in maximum grain zinc content of 24.1 mg/kg (28.19% increase over control). Use of chelators along with zinc in the pot culture experiment revealed that while addition of methionine further increased the grain yield, using histidine as a chelator increased the grain zinc content upto 27.71 mg/kg). Application of Zn increased total available zinc (TAZ; mmol/day) and maximum TAZ of 1.95mmol/day was observed with three sprays of 2270ppm of Zn. Addition of histidine as chelator further increased TAZ to a maximum of 3.7mmol/day.