INITIAL STUDY ON SICHUAN APOMIXIS RICE (SAR-1)

SAR-1 is a new germplasm which was discovered in the breeding material of southern multiplication in spring, 1988. The material showing high sterility of pollens is able to set seeds spontaneously. Under isolat ion, the seed-setting highest rate may reach 55.33%. The florets emasc ulated by clipping spikelet and lukewarm water still set seeds at cert ain rates. The completely sterile florets, after being emasculated and checked under microscope one by one, still set seeds, and the highest setting rate is 41.80%. Cytoembryological research indicates that the egg of SAR-1, without fertilization, divides independently into an em bryo, which follows the normal process to maturity. Adventitious embry os originate from ovary wall cells. Therefore, it is deduced that SAR- 1 has multiple mechanisms of apomixis, and the unfertilized polar nucl ei fuse and develop into endosperm cells. The endosperm provids the em bryo with nutrient for development. The automatic formation of the end osperm is an obvious feature of SAR-1. The parthenogenesis of SAR-1 ca n inherit from generation to generation and be transferred to other ma terials genetically.