Abstract: Asymmetric fusion of rice ( Oryza sativa L. ) protoplasts with protoplasts of apomictic Panicum maximum Jacq. by means of polyethylene glycol (PEG) method has been resulted to regenerate plants after selection and culture of the fused cells and that could be transplanted alive into soil. Before fusion, rice protoplasts were treated with 2.5 mmol/L iodoacetamide (IOA) at room temperature (22 to 25 ℃ ) for 15 min, while protoplasts of P. maximain were irradiated with 60 Kr soft X-ray. Dramatic variation was found on the flower organ morphology and stmcture,as well as re-production characteristics, etc. in the 28 flowering plants obtained. All of the plants showed abnormally increased number of anthers, ranging from 7 to 13. In some plants there were 2 to 3 ovules in a single ovary. In two plants there appeared to be more than 2 embryo sacs in a single ovule. Female and male fertility decreased greafiy and even vanished thoroughly. Only 5 regenerated plants produced seeds with low frequency. I-KI stainable pollen ranged from 0 to 68%. Cytoembryological observance showed that the non-seed-setting plants were female sterile,i.e. ,no normal embryo sac was differentiated in these plants.

Key words: Asymmetric somatic hybridization, Apomixis, Panicum maximum, Oryza sativa