Hence, a major part of ongoing staple plant research is focusing on the enhancement of the nutritional value of crops with aiming to increase the micro- and macro-nutrients. Yet, cereals or legumes lack sources of important micro- and macro-nutrients, which can result in serious human health problems. Grain legumes fulfill the requirement of protein and cereal crops have a high level of carbohydrate which offers ∼80% of calorie intake ( Lafiandra et al., 2014 Shewry and Hey, 2015). In recent times, contemporary agriculture is focusing on human nutritional improvement by generating improved varieties of staple crops such as rice, wheat, maize and grain legumes ( Ricachenevsky et al., 2019). Hence, a single plant is not enough to gratify human nutritional needs. Plant nutrients fulfilling human needs are called phytonutrients and different plants may contain different nutrients of altered levels. Being incapable of photosynthesis, animals including human beings depend upon plants for supporting their nutrition requirement either directly or indirectly. Furthermore, macronutrients (S, P, Mg, Ca, K, N, O, C, H) and micronutrients (Mo, Ni, Cu, Zn, Mn, B, Fe, Cl) are also essential parts of plants nutrition ( White and Brown, 2010). Apart from H and C, 15 other elements are important for the development of major plant species ( White and Brown, 2010). Plants acquire nutrition through the process of photosynthesis using H 2O and CO 2, in the presence of light. Nutrition is the foremost requirement for an organism to operate vital functions such as growth, development, and reproduction.
The superiority of biotechnology over conventional breeding being already established, it is essential to ascertain that there are no serious negative agronomic consequences for consumers with any difference in grain size or color or texture, when a nutritionally improved variety of rice is generated through genetic engineering technology. In addition to biofortification, our focus will be on the efforts to generate low phytate in seeds, increase in essential fatty acids or addition of vitamins (as in golden rice) all leading to the achievements in rice nutrition science.
We also compare the conventional breeding techniques of rice with modern molecular breeding techniques toward the generation of nutritionally improved rice variety as compared to other cereals in areas of micronutrients and availability of essential nutrients such as folate and iron.
In the present review, we summarize the research update on improving the nutritional characteristics of rice by using genetic engineering and mutation breeding approach. In addition to mutation breeding, genetic engineering approach also contributed significantly for the generation of nutrition added varieties of rice in the last decade or so. Several factors influence the nutrient content of rice which includes agricultural practices, post-harvest processing, cultivar type as well as manipulations followed by selection through breeding and genetic means. Rice is the prime staple food in more than thirty developing countries, providing at least 20% of dietary protein, 3% of dietary fat and other essential nutrients. Food with higher nutritional value is always desired for human health.