Soil and foliar zinc biofortification in field pea (Pisum sativum L.): Grain accumulation and bioavailability in raw and cooked grains

To evaluate the potential of cooked field peas to be used in Zn biofortification programs, all combinations of soil Zn application of 0, 4 and 8 mg ZnSO4 center dot 7H(2)O kg(-1) and foliar Zn application of 0 and two sprays of 0.25% or 0.5% (w/v) ZnSO4 center dot 7H(2)O before flowering and at early grain-filling stage were tested. Soil Zn application increased Zn-DTPA concentration 3.7- to 5.6-times depending on the Zn soil treatments. Grain Zn concentrations higher than 60 mg Zn kg(-1) were obtained with all foliar Zn applications, alone or in combination with soil Zn applications, and grain Zn bioavailability was adequate (phytate: Zn ratios lower than 15). Processing (freezing and cooking) caused a decrease of about 30% in grain Zn concentration and a 17%- increase in phytate: Zn ratios (to <= 9.5). The combined application of 8 mg ZnSO4 center dot 7H(2)O kg(-1) soil + 0.25% (w/v) ZnSO4 center dot 7H(2)O foliarly could be a good option for biofortifying field peas. (C) 2016 Elsevier Ltd. All rights reserved.