Diversifying crops for food and nutrition security: A case of vegetable amaranth, an ancient climate-smart crop

Abstract Drought is major abiotic stress that causes severe crop losses worldwide. Climate predictions indicate that the frequency of droughts will increase, impacting on global food supply. Currently, the agricultural sector is dominated by the three major crops (Zea mays), rice (Oryza spp.) and wheat (Triticum spp.), contributing to an increasingly uniform diet. The yields of these major crops are already affected by droughts, and the production stability is unpredictable due to uncertain weather. The promotion and development of new and highly nutritious crops and crop varieties with increased drought tolerance is one way to increase crop productivity in the face of climate change. Therefore there is an urgent need to explore alternative crops with the potential to fulfill the food requirements to complement these major crops. Amaranth (Amaranthus spp.) is an underutilized C4 vegetable and grain crop; a cheap source of protein, mineral, and vitamin; has a great amount of genetic diversity with high phenotypic plasticity; and possesses abiotic stress tolerance traits, including drought tolerance. Amaranthus spp. has been a source of nutritious food for many centuries in Africa, Asia, Central, and South America. Besides being highly nutritious, amaranth has a wide genetic pool and capacity to tolerate drought stress, making it a suitable crop for nutritional security in a rapidly changing world. This review presents information on the potential of leafy vegetable amaranth as a climate-resilient and nutrient-dense crop for food and nutrition security in a changing world.