STUDY OF CLIMATIC ADAPTABILITY OF TWO-LINE HYBRID RICE SEED PRODUCTION

The research on the climatic adaptability of the predominant sterile line, Peiai-64S, can provide references for decision-making in the production of two-line hybrid rice and the study of other sterile lines.The g row th model is constructed by using the number of days from seeding date to heading date and the corresponding meteorological data.The fertility model is developed based on the seed-set ting rate along with the corresponding meteorological data, and the switch indices of critical sterility induced by temperature and day-length are calculated. The 42-year meteorological data of 35 weather stations in China are input into the grow th model and the potential duration for the heading period (the duration from the earliest heading date to the latest heading date) is deduced for each station.According to the switch indices of critical sterility induced by temperature and day-length, the beginning and ending dates of the sterile and fertile duration under the guarantee rates of 80 %, 90 % and 95 % are given.During the sterile duration Peiai-64S can be used for producing hybrid seeds; and during the fertile duration, it can be used for multiplying itself.The results show that Peiai-64S can multiply only in Hainan Island or in the lower altitude area of the Yungui Plateau, whereas it can produce hybrid seeds in any rice production regions except Northeast China and the Yungui Plateau.The seasons for producing hybrid rice seeds are related to the altitude and latitude of the rice planting areas.