Protoplasts of common wheat ( Triticum aestivum L.2 n =42) cv. Jinan 177 were fused with ultraviolet (UV) irradiated protoplasts of Agropyron elongatum (2 n =70) via a PEG method. Sterile hybrid plants were regenerated from the fused product and their ovaries were induced to form calli.From the resulted callus tissue, green plants were differentiated. These somaclonal plants (SF0) were investigated using chromosome and isozyme analysis. The results showed that they contained chromosomes from both donors (i.e., Triticum aestivum and Agropyron elongatum ). Two of the SF0 plants grew to maturity and set seeds. The analysis of phenotype, chromosome constitution, isozyme pattern and RAPD polymorphism of the F 1 plants confirmed their hybrid nature. Collectively, these results demonstrated that fertile hybrid plants could be produced from the procedure described above. Three different phenotypes were observed in F2 progenies. The type I and II plants had higher stalks (average 75～85 cm) and big ears and grains, but plants of the former phenotype possessed fewer tillers. Type III plants had short stalks (average 55 cm) but possessed high ability of tillering. Cytogenetical analysis of F 1 plants and their successive generations showed that in F 1 to F 3 generations the chromosome numbers of root tip cells varied in the range of 36～44, and many cells contained 1 4 micro chromosomes (mc). In PMC MI stage of the F2 plants, the chromosome configuration was mainly 17II 22II with 1 4 additional micro chromosomes. Comparing to F 2, more chromosome configuration of 20II 21II occurred in F 3, and over 70% of cells had the chromosome configurations of 21II+1 2 mcs. A large population of the different hybrid lines have been obtained through propagation and selection in successive generations. Their agronomic traits have been studied and will be reported in a separate paper.
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