Research evidence has indicated that, on the bases of delivery
effectiveness and economic consequences, enhanced Fe intake
through biofortified rice (rice grains with increased contents and/
or bioavailability of Fe through agronomic or genetic improvements) is the most favorable approach in the long term. In light of
this concept, both methods of conventional breeding and genetic
engineering have been applied to increase the Fe content in the
polished rice grains (Welch and Graham, 2004). Several transgenic
rice varieties with enhanced Fe contents (e.g. 8.9 and 15 mg kg
1
for BR29 and IR68144, respectively) have been developed (Sellapan
et al., 2009). However, the safety of transgenic rice is still a major
concern for most of the consumers, even though it is likely to be
equivalent to that of conventional rice. Thus, it appears that the
conventional breeding method, such as mutation breeding, is still a
non-controversial approach to produce genetic sources for
particularly desired characteristics (e.g. high Fe or Zn contents
in polished rice grains) (Fig. 1)