1. INTRODUCTION
Zinc deficiency in rice has been widely reported
in many rice-growing regions of the world [1-3].
Zinc deficiency in crop plants results in not only
yield reduction but also Zn malnutrition in
humans, where a high proportion of rice is
consumed as a staple food [4,5]. Low
bioavailability of Zn in soil generally results in Zn
deficiency in rice plants, and thus becomes one
of the common constraints for Zn bio-fortification
in rice grain. Zn deficiency in rice can be
alleviated through Zn fertilization, which is
considered to be a cost-effective method to
alleviate Zn malnutrition [6].