STRATEGIES FOR AGRONOMIC BIOFORTIFICATION OF POTATO TUBERS WITH ZINC

Abstract

Current study explored the possibility of increasing zinc (Zn) content in potato tubers by foliar, seed tuber
soaking, and soil application of Zn fertilizers. During first year, a single application of 5 kg Zn ha-1 through zinc sulphate
(ZnSO4) increased the Zn concentration by ~30 % followed by split application of ZnSO4 (19.6%), and a single application
of 1 kg Zn as Zn-EDTA (17.6%) in whole tubers. Single and split soil application of either zinc sulphate (5 kg ha-1) or
zinc-EDTA (1.0 kg Zn ha-1), foliar application (ZnSO4) and soaking of seed tubers in zinc sulphate solution before planting
also increased its concentration significantly in tuber peels. During 2nd year of experimentation, a single soil application
of zinc sulphate (5 to 10 kg Zn ha-1), Zn-EDTA (1 to 2 kg Zn ha-1) increased the Zn concentration in peeled (tuber flesh)
as well as unpeeled whole tuber significantly. Application of 2 kg zinc as Zn-EDTA resulted in highest increase of 4.4 mg
kg-1 Zn (25.7%) in tuber flesh which was comparable with 10 kg Zn as ZnSO4 (24.9%). On application rate basis, compared
to ZnSO4, the 5-times lesser quantity of chelated Zn resulted in equivalent increase in tuber Zn concentration. Since, the
bioavailability of Zn from potatoes is high, the soil application of Zn fertilizers during the initial crop growth stage, as
revealed by this study, can be adopted as a simple strategy to increase its content in tubers for addressing Zn - related
malnutrition issues.