Abstract: Using the theory of climatiac potentul productivity,and evaluating the quantitative influence of solar radiation,temperature and water on the growth of maize,a set of models for estimating the potential yields of maize on the basis of climatic.data was established.The calculated optimum seeding date,for the medium variety,is the last 20 days of May,and for the early variety,is the first 20 days of June.It fits the results of field tests quite well.It is also identified that the technique of postponing seeding date while waiting for rain conforms to the pattern of climate,and is an effective way to avoid drought and increase yield.In accordance with the pattern of climate in the mountainous region,a complete set of the " elevation-seeding date-variety" technique was established.

Key words: Rainfed maize (corn), Optimum seeding date, Postponing seeding date, While waiting for rain, Climatic potential productivity