Abstract: Two transgenic rice lines: Zhendao88 with Cry1Ab gene and Shengdao301 with Xa21 gene were crossed. The genetic segregation pattern and stability of the transgenes in the hybrid progenies were studied by testing selection marker genes (including bar gene and gus gene) and Southern blot analysis. The result shows that in hybrid progenies the bar gene and Xa21 gene co-inherited and co-expressed, respectively. Basta resistance assay and Gus histochemical staining assay indicated that the F2 generation showed a typical Mendel segregation ratio of 9:3:3:1 and stable homozygotes of Cry1Ab and Xa21 began to appear in the F3 generation. Southern blot assay of F3 generation and parental lines showed that the Cry1Ab gene and Xa21 gene could be steadily inherited. By field breeding, we finally acquired 3 transgenic lines with good agronomic traits: SK-1, SK-2, and SK-3, which all showed obvious resistance to stripe stem borer (Chilo suppressalis) and Xanthomonas oryzae pv. oryzae. The yield potentials were about 20% higher than those of Zhendao88 and Shengdao301; the quality was similar and some features were better.

Key words: Rice, Borer resistance, Bacterial blight resistance, Inheritance and expression, Stability