Screening of Aromatic Rice Cultivars for Bacterial Leaf Blight (BLB) Disease Resistance Gene Xa5 through Molecular Marker.

Bacterial leaf blight (BLB) caused by Xanthomonas oryzae pv. oryzae (Xoo) is one of the most common devastating diseases of rice (Oryza sativa) all around the world. Thus, present study has been conducted to screen 12 aromatic rice cultivars (Atashail, Basmati, Kalizira, Uknimodhu, Zira katari, BR5, BR14, Bina dhan9, BRRI dhan34, BRRI dhan37, BRRI dhan38 and BRRI dhan50) for BLB resistant gene xa5. The genotypes were analyzed using two genetic markers (RM 122 and RM 390) by Polymerase Chain Reaction (PCR). Where, BR 14 that was resistant to BLB was used as control. Both primers generated different banding patterns. Primer RM 122 produced 6 bands whereas primer RM 390 produced 10 bands, respectively. The highest level of gene diversity value (0.8889) was observed in locus RM 390 and the lowest level of gene diversity value (0.7361) was observed in locus RM122 with a mean diversity of 0.8125. The PIC values ranged from a low of 0.7007 (RM 122) to a high of 0.8785 (RM 390) with an average of 0.7896. Using the linked primer RM 122, the bands of xa5 gene were standardized by the amplified DNAs. The DNA band of 246 bp was considered as resistance line and the DNA band of 230 bp was considered as a susceptible line. Similarly, in case of primer RM 390, 70 bp was considered as a resistance line and 112 bp was considered as susceptible line. Basmati, BRRI dhan50, Kalizira Atasail, Bina dhan9, Uknimodhu, BR 34, BR 37 and Zira Katari all of them found as partial resistant to BLB diseases. However, BRRI dhan38 was found as partial or complete susceptible cultivar.