Golden rice is a variety of rice (Oryza sativa) produced through genetic engineering to biosynthesize beta-carotene, a precursor of vitamin A, in the edible parts of the rice. It is intended to produce a fortified food to be grown and consumed in areas with a shortage of dietary vitamin A. Vitamin A deficiency causes xerophthalmia, a range of eye conditions from night blindness to more severe clinical outcomes such as keratomalacia and corneal scars, and permanent blindness. It also increases risk of mortality from measles and diarrhea in children. In 2013, the prevalence of deficiency was the highest in sub-Saharan Africa (48%; 25–75), and South Asia (44%; 13–79). Although golden rice has met significant opposition from environmental and anti-globalisation activists, more than 100 Nobel laureates in 2016 encouraged use of genetically modified golden rice which can produce up to 23 times as much beta-carotene as the original golden rice. History Research for development of golden rice began as a Rockefeller Foundation initiative in 1982. In the 1990s, Peter Bramley discovered that a single phytoene desaturase gene (bacterial CrtI) can be used to produce lycopene from phytoene in GM tomato, rather than having to introduce multiple carotene desaturases that are normally used by higher plants. Lycopene is then cyclized to beta-carotene by the endogenous cyclase in golden rice. The scientific details of the rice were first published in 2000, the product of an eight-year project by Ingo Potrykus of the Swiss Federal Institute of Technology and Peter Beyer of the University of Freiburg. The first field trials of golden rice cultivars were conducted by Louisiana State University Agricultural Center in 2004. Additional trials were conducted in the Philippines, Taiwan, and in Bangladesh (2015). Field testing provided an accurate measurement of nutritional value and enabled feeding tests to be performed. Preliminary results from field tests showed field-grown golden rice produces 4 to 5 times more beta-carotene than golden rice grown under greenhouse conditions. Crossbreeding As of 2018, breeders at the Philippine Rice Research Institute, the Bangladesh Rice Research Institute, and the Indonesian Centre for Rice Research were developing golden rice versions of existing rice varieties used with their local farmers, retaining the same yield, pest resistance, and grain qualities. Golden rice seeds may cost farmers the same as other rice varieties. Approvals In 2018, Canada and the United States approved golden rice, with Health Canada and the US Food and Drug Administration