Impacts of combination of foliar iron and boron application on iron biofortification and nutritional quality of rice grain

To increase iron (Fe) concentration in edible portions of staple food crops, an agronomic approach via foliar Fe-containing solutions might be sustainable and economical strategy; however, little information is available in the literature. So the present work was carried out to examine the effects of Fe in association with boron (B) foliar fertilization on Fe biofortification and the nutritional quality of rice (Oryza sativa L.) grain. The work was conducted in 2006 at the research experiment station at Zhejiang University on japonica rice 'Bing 98110' planted on a silty loam soil in pots. The following spray treatments were performed at rice anthesis: (1) control (the deionized water spray); (2) 0.1% (w/v) FeSO4 center dot 7H(2)O; (3) 0.1% (w/v) Fe(II)-AA (Complex of 0.1% FeSO4 center dot 7H(2)O and 0.4% compound amino acids; 18.6% N); (4) 0.2% (w/v) H3BO3 (boric acid, 17.5% B); (5) combined spray of 0.1% (w/v) FeSO4 center dot 7H(2)O and 0.2% (w/v) H3BO3; (6) combined spray of 0.1% (w/v) Fe(II)-AA and 0.2% (w/v) H3BO3. Foliar Fe and B complex application did biofortify Fe concentration and other measured nutritive values in polished rice. Compared to the control, Fe concentration in seed increased significantly 18.9% with the combination of foliar Fe(II)-AA and B, Zn content increased significantly 26.7%, and protein and total 16 amino acids, such as lysine, threonine, and arginine that were essential for human nutrition as well as glutamic acid, aspartic acid, valine, leucine, and phenylalanine, etc., also increased markedly by 30.9% and by 37.0%, respectively.