Transgenic elite Indica rice varieties, resistant to Xanthomonas oryzae pv. oryzae

The agronomically important Indica (group 1) rice varieties IR64, IR72, hyb rid restorer line Minghui 63, and BG90-2 were co-transformed by microbombar dment of embryogenic suspensions with plasmids that contain the Xa21 gene w hich confers resistance to Xanthomonas oryzae pv. oryzae and the hph gene f or resistance to hygromycin B. Six of the 55 transgenic R0 plant lines cont aining the Xa21 gene displayed high levels of resistance to the pathogen, a nd no partial resistance was observed. The trait was stably inherited in su bsequent generations, and transgenic plants are currently in field tests. T he ability to transfer agronomically important genes into elite Indica rice varieties demonstrates the applicability of genetic engineering for the ag ronomic improvement of rice.