Molecular Marker-based Screening for Bacterial Leaf Blight Resistance Genes in Landraces and Cultivars of Rice in Gujarat

Bacterial Leaf Blight (BLB) caused by Xanthomonas oryzae pv. oryzae (Xoo) is the most devastating disease and limiting factor for rice productivity worldwide. Since BLB pathogens are difficult to manage through chemical and other available cultural practices, development of host plant resistance is the most effective means of disease management. So far survey for resistance donor at molecular level in rice is scanty and the landraces of Gujarat state of India have received little attention. Therefore, a molecular screening was conducted to identify the presence of major BLB resistance genes Xa4, xa5 and Xa21 in landraces and local cultivars of Gujarat. In order to confirm the presence of BLB resistance genes, 25 genotypes were screened using PCR analysis. 10 genotypes (IR20, IR64, IR72, NWGR1095, NWGR2014, IET14726, GR7, GR102, Pankhali 203 and Ratna) were found to be Xa4 positive. In contrast, only IET18483 genotype was found to be Xa21 positive. Interestingly, not a single genotype was found to be positive for xa5 BLB resistance gene. The status of BLB resistance genes in landraces and cultivars of Gujarat will help design BLB-resistance breeding programs.