Efficacy of zinc application methods for concentration and estimated bioavailability of zinc in grains of rice grown on a calcareous soil

Zinc biofort ification of cereal grains is suggested for controlling widespread human zn deficiency in developing countries. in present field trail,various zn treatments [control,priming of seeds in 0.5% (w/v) zn solution (seed priming),dipping of roots in 0.5% (w/v) zn solution (root dipping),application of 20 kg zn ha −1 (soil application),sprays of 0.25% (w/v) zn each at tillering and heading stages (foliar application) and combination of soil + foliar zn applications] were applied as znso4·7h2 o to rice grown under submerged conditions on a zn deficient calcareous soil. treat ments significantly (p≤0.05) increased grain and straw yield; however,seed priming and root dipping increased paddy yield only by ≤5%. increased grain weight also significantly increased grain phytate content. whole grain zn concentration increased from 22 (at control) to 29 mg kg −1 (at soil + foliar application).zinc applications methods,especially soil + foliar applicat ion,decreased grain [phytate]:[zn] rat io and increased estimated human zn bioavailability in grains based on trivariate model of zn absorption. conclusively,soil + foliar zn application is suitable for opti mum paddy yield and agronomic zn biofortification of rice grains. however,a limited increase in grain zn concentration (7 mg kg −1) by zn application suggested exploitation of molecular and genetic approaches in zn biofortification programs. © 2015,university of agriculture. all right reserved.