Rice is the major diet for over 2 billion poor in developing countries. It is an excellent source of calories, but does not contain any pro-vitamin A.

The consequence is widespread vitamin A deficiency in rice-depending populations which are to poor to buy a diversified diet. Since the early 90's the concept of ‘bio-fortification' is gaining attention, which is exploiting the potential of genetics for an improvement of the micro-nutrient content of major crops.