Rice materials
Two rice varieties IR68144 and IR64 were supplied by Dr. Gregorio at IRRI. The Fe concentration in brown rice of IR68144 was about 20.4 mg/kg with a stable inheritance and the inheritance was not affected by soil moisture, soil pH and fertilizer management [8, 11],whereas the Fe concentration in brown rice of IR64 (amain variety in the Philippines) was only about 11.2 mg/kg. According to the results from IRRI, Fe concentration ranged from 7.5 to 24.4 mg/kg with a
mean value of 12.1 mg/kg in the 939 samples analyzed [8, 11]. Thus, IR68144 belonged to Fe-dense rice with higher Fe concentration in grain, and IR64 to non Fe-dense rice with lower Fe concentration in grain.