Improving Water Use Efficiency and Nitrogen Use Efficiency in Rice Through Breeding and Genomics Approaches

Rice is a staple food of more than half of the world’s population; more than 3.5 billion inhabitants depend on rice for obtaining 20% of their daily calorie intake. Nitrogen is the most important for crop growth and yield potential. Indeed, nitrogen is essential to stimulate tillering, leaf growth, photosynthesis, and protein synthesis. Significant achievements have recently been observed at the molecular level in nitrogen use efficiency and water use efficiency in plants. In this chapter we will discuss the following issue: (i) definition of both nitrogen use efficiency and water use efficiency, (ii) genes responsible for nitrogen use efficiency and water use efficiency, (iii) best ways for improving water and nutrient use efficiency in rice, and (iv) optimizing nitrogen options for improving water and nitrogen use efficiency of rice under different water regimes.