In agricultural research field experiments are usually conducted with the sam etreatments in the same experimental design over several locations for several years in order to draw widely adaptable results. For generalization of the results from the individual locations and the properties of the treatment responses may be evaluated by carrying out the combined analysis over agricultural climate zones or country level. A method of combined analysis of variance was presented and examined by applying to a set of data obtained from a series of rice variety adaptability trials conducted by Kyung Buk Provincial Office of Rural Developmention 1986.