Semidwarf Rice and Wheat in Global Food Needs

Rice and wheat together provide about three-fourths of the total food-grain supply consumed by man. Because of rapidly increasing population, per capita grain output in the underdeveloped regions of the world delined during the 1940's and 1950's. Fertilizer is a key factor in increasing agricultural production. Recently, several underdeveloped nations made major efforts to increase the use of fertilizer. But traditional varieties of wheat and rice did not respond to fertilizer efficiently. Attempts to breed fertilizer-responsive varieties were generally unsuccessful until plant breders discovered the Chinese rice Dee-geo-woo-gen and the Japanese wheat Norin 10 and used them in breeding programs. This resulted in the development of the semidwarf rice, Taichung Native 1, in 1956 in Taiwan and the semidwarf wheat, Gaines, in 1961 in the U. S. A. The most extensive use of the semidwarfing genes was made by the Mexican wheat program and at the International Rice Research Institute. Several Mexican semidwarf wheats released in the early 1960's revolutionized wheat production in Mexico and contributed to the beginning of similar revolutions elsewhere. The rice variety, Taichung Native 1, made some impact, but the real breakthrough in rice production in Asian tropics came with the release of IR8 in 1966. The success of semidwarf varieties resulted in unprecedented seed exports from Mexico and the Philippines and rapid spread of new seeds in a short period of time. During 1969-70 the new seeds, which were grown on about 20 million hectares (17 million ha in Asia alone), produced a substantial increase in the food-grain production. National yields in Asia which were stagnant for 20 years started rising during the last 5 years. The Philippines became self-sufficient in rice and Pakistan self-sufficient in wheat. Production of wheat in India and of rice in West Pakistan almost doubled during the last 5 years. The semidwarf wheats and rices have begun to make an impact on food production in many other countries. Short stiff straw and short erect leaves appear to be most important attributes of an efficient plant type. Intensive and continued research is needed to capitalize on the potential of the semidwarf plant type by incorporating resistance to diseases and insects. Basic studies leading to new ways to increase yield potential should be made. Although the new strains offer a potential of greatly increased rice and wheat production, the food problem can be effectively solved only if attempts at increasing foo supplies are accompanied by population control.