Techniques And Extention Of Hybrid Rice Seed Production In The Area Of West Zhejiang

The comprehensive technique for producing hybrid rice seeds with high quality and yield, suitable for the ecological conditions in west Zhejiang, was proposed in the present paper, based on reviewing of current achievements in hybrid rice seed production made both in China and world, and by using the relevant results from the experiment done during 2000-2003. The main results are as follows:1 The sysmatical observation of growth and development was made on the major hybrid rice combinations currently used in West Zhejiang, includingrestoring lines Miyang 46, Minghui 63, Zheda 8220, R3027 and sterile lines II-32A, Xieqingzao A, and some important parameters, including duraing from sowing to heading date, leaf number of main shoot were determined, which provided the valuable references for correct choice of hybrid combinations and productive season, and proper determination of sowing date of both parents and predicting of flowering date.2 The newly released resotring line, Zheda 8220 was characterized in terms of growth and development, and basis on the investigation; the techniques for production of high yield hybrid seeds were developed for other hybrid combinations. The results also provided the methodology for studying hybrid seed production of other new combinations.3 Special surveys and experiments were done on the influence of field management, seed sunning, store and germinated seed treatments on the germination performance, in order to determine the constraints limiting germination and searching for the strategies to improve the germination. It was found that seed sunning store condition were the major factors affecting the germination, beside the whether which is beyond our control.4 According to. the practical experince and experimental results, it may be concluded that suitable season for production of hybrid rice seed in West Zhejiang is early summer, exactly during 10 to 20, July, when summer rain season is just over and the maximum temperature is not coming, thus it is the optimal stage for heading and flowering of both parents. The systemic measurements should be conducted in field management, focusing on th correct choice of date difference in sowing sterile and restoring lines, development of strong seedlings, in particular for male line, growth stimulation of both parents, which has been proven to be effective in improvement of hybrid seed yield. Meanwhile it could also avoid natural pollination from other early season rices due to the different date in heading and flowering, resulting in high seed purity. It could be effective in controlling grain black powdery disease and thus improving seed quality. After harvesting hybrid seeds, it is possible to plant a late season rice, increasing utilization of land, light and temperature, and alleviating the conflict between hybrid seed and food production.