A Robust and Cost-Effective SGOC Method for Testing Rice Iron Concentration in Biofortified Breeding

Abstract

Iron is an important micro-nutrient to human health. Malnutrition of iron is a serious problem associated with resource poor population in many developing countries. Development and consumption of iron-rich rice ( Oryza sativa L.) varieties are considered one of the ways to solve this problem. To facilitate large-scale screening of breeding materials for iron concentration in the rice iron-biofortified breeding program of China, a new method “surging and grind-milling of orthophenanthroline colorimetry testing (SGOC)” was developed. Based on the testing results of 3 sets of 84 diverse rice genotypes that differ greatly in grain iron concentration, the correlation coefficient was as high as 0.87 between the SGOC method and the standard ICP-MS testing method. The per sample cost of the SGOC method was about 0.1 US dollar or 50 times less the ICP-MS method, indicating that the SGOC method is robust, fast, and cost-effective, particularly useful for preliminary screening of the iron concentration of large numbers of early generation breeding materials. The iron concentration of processed rice that tended to be significantly increased when milling and polishing with iron-made equipment was also eliminated in the SGOC method. Based on the analysis of iron concentration in 59 backcross progenies, the introgression of genes/quantitative trait loci for high iron concentration from high iron rice germplasm into elite local rice varieties is an efficient way to develop high yielding rice varieties with significantly improved rice iron concentration in future rice biofortified breeding.