Assessment of natural chelates to enhance zinc biofortification in cassava (Manihot esculenta Crantz)
The study examined the potentials of some organic chelates to enhance zinc availability, uptake and deposition in the edible root of cassava. The chelates used were EDTA as standard chelate, Bontera as commercial organic chelate and periwinkle effluents and Smoke solution as local organic chelates. The cultivars used were TME419 and TMS3168/UMUCASS/36 also known as YELLOW ROOT (YR). One hundred (100ml) of 100μg of zinc obtained from zinc oxide was added to 5000ml each of deionized water, 1ml/L Bontera, 1ml/L EDTA, Periwinkle effluents and Smoke solution. The treatments were applied through foliar application at 3 months after planting. The zinc concentration distribution ranged from 13.627μg/g (YR peel; control) to 85.843μg/g (YR edible root; EDTA +ZnO). In the edible root, the bioavailable zinc ranged from 18.494μg/g (YR; Boontera+ ZnO) to 85.843μg/g (YR; EDTA +ZnO). After processing to garri and fufu, the content ranged from 0.2116mg/100g (TME419; control) to 1.1645mg/100g (YR; Smoke solution + ZnO) in fufu and 1.0178mg/100g (YR, Bontera +ZnO) to 4.494mg/100g (TME419; PE +ZnO) in garri. After seven months storage, TME419 retained Zn in 30% of the treatments, while YR retained Zn in 60% of the treatments. The study revealed that organic chelates have good potentials to enhance zinc biofortification. Periwinkle effluents proved to be better because it retains the nutrient for longer period after processing to garri. YELLOW ROOT proved to be better because it can retain zinc for a longer period. The use of organic chelates should be encouraged for micronutrients sufficiency, sustainable agriculture and food security.
Keywords: Organic chelates, Zinc, Bioavailability, Cassava