Rice is the most important and prestigious food crop of Nepal. It is grown in a diverse environment ranging from tropical plains to foot of the mountain at highest elevation (3050 masl) in Chhumchure, Jumla. Nepal is considered as one of the origin center of rice. It is one of the most important cereal crops in Nepal. Rice is grown in 1440 thousand ha and the productivity is 2.56 t/ha. It contributes nearly 20 per cent to the agricultural gross domestic product and provides more than 50 per cent of the total calorie requirement of the Nepalese people. Productivity increment is the only way to increase the production. The promising technologies generated by agricultural research play the pivotal role to increase productivity. Nepal has released fifty five (55) rice varieties with full package of growing practices in the last 40 years. The coverage by improved varieties is 85 percent of the total rice cultivated land. Popularly cultivated improved varieties are Radha-4, Radha-12, Masuli, Sabitri, CH-45, Bindeswori in terai, Khumal-4, Khumal-11, Taichung-176, Chainung-242 in Mid-hills and Chandannath-3 in High-hills.