Rice Biofortification—Progress and Challenges in Improving the Nutritional Value of Rice ^†

Rice is the principal source of calories for more than half of the world’s population, and while an excellent source of energy is a relatively poor source of micronutrients. Developing rice varieties with increased levels of bioavailable micronutrients is a sustainable and complementary approach to tackle micronutrient malnutrition, and may be achieved through transgenic or conventional breeding approaches. Using the former approach Golden Rice has been genetically engineered to produce β-carotene in the grain to address the persistent and pervasive problem of vitamin A deficiency, while high levels of iron and zinc have also been achieved via a transgenic approach. The primary focus of conventional breeding is increasing zinc content. This paper reports on the progress and challenges in developing and delivering rice with improved micronutrient content.