Morpho-Molecular Screening for Bacterial Leaf Blight Resistance in Some Rice Lines and Varieties

Abstract

Bacterial leaf blight (BLB) is one of the major and oldest diseases of rice. The best cost effective management of this disease is the development of resistant cultivars. Morphological and molecular screening are widely used approach in the recent scenario for identifying BLB resistant cultivar. In present study, two experiments were carried out to identify the BLB resistant rice lines and varieties. An active strain of Xanthomonas oryzae pv. oryaze (Xoo.) BXO-09 was used for the inoculation experiments. Then, morphological rating was done to find out the resistant rice lines and varieties whereas three RFLP primers (RG136, RG556 and pTA248) were used for identifying the BLB resistant genes. Through morphological analysis, the rice line RC251 was recorded as susceptible where the rest of the rice lines resulted moderately susceptible or moderately resistant. Among the rice varieties, BR-26, BRRI Dhan31, IRBB5, IRBB21, IRBB60, IRBB65, and Kumragur were recorded as resistant where BR-11, Binadhan-8, and Binadhan-10 were found highly susceptible to BLB. In case of RFLP marker based analysis, a specific type of banding pattern was observed for IRBB5 for RG556 primer which indicated the presence of xa5 gene. For RG136 primer 8 kb single band was formed for different lines and varieties whereas only IRBB60 showed 2 fragments of 8 kb and 5 kb which also indicated the presence of xa13 gene. Finally, DNA amplification of 27 rice lines and varieties using pTA248 primer showed the band at 4 kb position for the BLB resistant lines and varieties and 3.7 kb position for the susceptible lines and varieties. The findings of morpho-molecular characterization information could be useful to the breeders for further planning of developing BLB resistant cultivars.