Molecular Characterization and Identificaiton of Blast Resistance genes in Indica Rice

Abstract

Twenty two rice genotypes were subjected to DNA finger printing and were evaluated for resistance to blast disease under induced epiphytotic conditions. The disease severity(%) and AUDPC was lees than 46% and higher than 1 000 in case of susceptible genotypes. Out of twenty two, thirteen varieties were resistant for blast disease. The rest nine were susceptible under artificial conditions. Ten gene specific primers were used to identify blast resistant genes in rice genotypes. Out of ten molecular markers used only seven gene specific markers Pi1 (350 bp J, Pib(325bpJ , Pi2 (1200bpJ• pi/(1(990bpJ.Pi5-1 (710bp)r Pi9 (1600bpJ• PizMRG 4961(32sbpJ were linked to blast resistance genes. The eleven resistant genotype had varying number of resistant genes. Maximum six genes were detected in vivekdhan-154. The genotype VLD-65 had four genes for resistance and expressed maximum resistance against the disease. In some cases role of environmental factors for expression of genes was also noticed. Allelic relationship among resistant genotypes was observed. A detailed breeding strategy for development of improved varieties of rice has been discussed. The blast resistant varieties VLD-85, VL-31077, Vivekdhan-154, VLD-81, VLD-221, VLD-65, Vivekdhan-82, VLD-86, Vallabh Basmati-21 were suggested to be use in crossing with among selves and with popular varieties for development of improved varieties of rice using selection methods. Application of back cross method involving these blast resistance varieties as non recurrent parent for development of blast resistant varieties of basmati ri r has also been suggested.