Resistance of IRBB21(Xa21) to five races of bacterial blight in Guangdong Analysis of Genetic Background and Agronomic Traits in Improved Restoring Lines Shuhui 527 with Resistance to Bacterial Blight Comparative Physical Location of Rice Xa 21 Gene in Rice and Maize Using the BAC-FISH Approach Developing Rice Lines Resistant to Bacterial Blight and Blast with Molecular Marker-Assisted Selection Identification of Resistance gene Xa21 in Yunnan Wild Rice Study on Resistance Gene to Bacterial Blight Xa21 Transgenic Rice and Their Hybrid Combinations