ABSTRACT
Plant responses to environment determine the adaptation of plants and influence the improvement of cropping systems that can be achieved through changes in management practices and plant breeding. Increases in crop production efficiency are required in all countries to maintain profitability and enhance sustainability of agricultural enterprises, and to contribute to environmental health. Increases in the efficiency of irrigation and use of agricultural chemicals are needed because, in addition to enhancing the profitability of agriculture, they can reduce damage to the environment. Reducing irrigation requirements can make more water available for maintaining natural aquatic systems. In many watersheds, competition with domestic, industrial, and environmental requirements will reduce supplies of water for irrigation. Global climate change will result in increases in level of seawater and greater flooding of some delta and low-lying areas that would negatively impact production of rice and other crops.
