Genetic Diversity of Bacterial Leaf Blight Disease in a Set of Rice Landraces of West Bengal

Bacterial Leaf Blight (BLB) is a major disease of rice in tropical monsoon and sub tropical rice growing regions of the world. BLB substantially reduces the yield of the crop affecting food security. Rice is the second most important food crop, after wheat, in the world; hence the disease must be effectively controlled. As chemical control is impractical due to unavailability of specific bactericides, the focus is on the use of resistant genotypes. Landraces are repositories of resistance to biotic and abiotic stresses. During the process of domestication and cultivation of crop plants, a wealth of genetic diversity has been created, utilized and partly preserved with valuable allelic variations of traits of economic significance. These variations can be discovered and effectively used to meet the existing and emerging challenges that threaten world food security. In this study we have used a set of 30 rice landraces from West Bengal to assess the genetic diversity 1. At the disease phenotype level through artificial inoculation and measurement of lesion length. 2. In the variation pattern of bacterial infection of the xylem vessel in the resistant, partially resistant and susceptible accessions using scanning electron microscopy, and 3. At the DNA level using six markers linked to the resistant genes xa-5, Xa 21, xa13, Xa 10, xa 8, and xa 24. Substantial diversity was observed and the results on these three areas are presented. 86 Bipasha Roy et al In the future, this set of landraces will be assessed for diversity using primer pairs designed from the conserved regions of cloned and characterized BLB resistance genes, and sequencing the amplified products. Attempts will be made to correlate the band length and sequence variations with the disease phenotype. KeywordsOryza sativa; Landrace; Xoo;BLB;Genetic Diversity; Scanning Electron Microscopy; Linked Markers.