Identification of Indian rice germplasm lines with bacterial leaf blight (BLB) resistance genes

Bacterial leaf blight of rice, caused by Xanthomonas oryzae pv. oryzae is one of the major constraints limiting rice production and productivity in South East Asia, particularly in Japan, Philippines, Indonesia, China and India. No effective chemical control for the disease is available. It is therefore, important to identify lines resistant to blight, which can then be used as parental lines in breeding programmes. Gene-linked and gene-based molecular markers and well defined donors are available for most of these genes. In the present study, a total of 386 Indian rice germplasm lines including commercially cultivated Indian rice varieties were screened for the presence of four bacterial blight resistance genes i.e. Xa4, xa5, xa13 and Xa21. The rationale behind the study was to identify new hitherto unreported, rice lines carrying BLB resistance genes and studying the allelic distribution of these genes in the germplasm.