Crop Biotech Update

Pyramiding Resistance Genes to Combat Bacterial Blight in Hybrid Rice

May 18, 2012

Bacterial blight caused by Xanthomonas oryzae pv. oryzae is a notorious rice disease especially in Asia. The disease can bring about 20 to 50 percent decreases in rice yield. Host-plant resistance is known to be an economical and favorable approach in managing pests such as bacterial blight.

Yanchang Luo from the National University of Singapore and other scientists conducted a study to breed a broad-spectrum and high disease resistance in hybrid rice. They introduced three resistance genes (Xa4, Xa21, and Xa27) into the restorer lines of Mianhui 725 (MH725) or cultivar 931. The resistance genes were then pyramided in a single line chosen in the progeny of the two lines. Through marker assisted selection, the team developed the lines 9311 (Xa27) and WH421. A new restorer line carrying the three resistance genes was labeled as XH2431, which was chosen from the cross between 9311(Xa27) and WH421. II You 2431, the hybrid derived from the cross between II-32A and XH2431, produced high yield, showed good restoring ability and conferred high disease resistance to bacterial blight.

Results showed that the development of XH2431, 9311 (Xa27) and WH421 provides a set of restorer lines exhibiting broad-spectrum and improved resistance to bacterial blight in hybrid rice.

Read the research article at