Department of Plant Breeding and Genetics, Punjab Agricultural University, Ludhiana-141 004
National Symposium on Strategic Issues in Plant Pathological Research held at Department of Plant Pathology, CSK HP Krishi Vishvavidayalaya, Palampur on November 24–25, 2011
Advanced breeding lines of rice developed at Punjab Agricultural University were evaluated against ten pathotypes of Xanthomonas oryzae pv. Oryzae (virulent to single xa/Xa gene and gene combinations) of bacterial blight pathogen prevalent in Punjab, sheath blight and brown spot under artificial inoculation conditions as well as against false smut under natural conditions during kharif seasons 2010 and 2011. A total of 81 entries were tested in three replications. Most of the lines possessed bacterial blight resistance genes and gene combinations (xa13+Xa21 and xa5+xa13+Xa21). All 81 lines showed resistance to the most prevalent pathotype PbXo-7 of Xanthomonas oryzae pv. oryzae. Fifty one entries were found to be resistance to all the pathotypes, however, 31 lines showed susceptibility to the newly identified pathotypes Pt 902 and Tar 949 which are virulent to Xa gene(s) and gene combinations (xa13+Xa21 and Xa4 +xa5). Against sheath blight, brown spot and false smut, 2,14 and 13 entries showed tolerance, respectively. Advanced line viz. PAU4058-6-5-1-6 and PAU3842-52-1-2-1- possessed resistance to all the pathotypes of bacterial blight pathogen along with tolerance to sheath blight and false smut. However, some lines viz. PAU3832-44-6-3-3-1, PAU3832-44-6-3-3-2, PAU3832-79-4-1-3-1, PAU3832-194-4-3-1-3, PAU3879-33-1-2-2-1 and PAU3750-5-1-1-2-1-3 showed good resistance to all the pathotypes as well as good tolerance to false smut. In addition, five lines i.e. PAU3870-57-4-1-1-2, PAU3871-69-10-2-1-1, PAU3745-7-6-1-2-1-3 and PAU3745-7-6-1-2-1-3 alos showed resistance to all the BLB pathotypes and tolerance to brown spot. These genotypes can either be released as new varieties or further utilized as donors in multiple disease resistance breeding programmes.
