GENETICS AND BREEDING FOR BLAST AND BACTERIAL LEAF BLIGHT RESISTANCE OF RICE (Oryza sativa. L)

Genetics for bacterial pathogens are difficult to manage. Development of host plant resistance is the most effective means of disease management. As many as genes conferring resistance (bacterial blight) and some genes for resistance to blast have been identified to various races of the pathogen have been identified and utilized in rice breeding programs. To evaluate the genetic backgrounds and introgression of resistance genes from donor varieties, the graphical genotypes of the population were constructed using 3 simple sequence repeats RM44, RM111, RM 483 and φX174 – Hae III. However, large-scale and long-term cultivation of varieties carrying a single gene for resistance resulted in a significant shift in pathogen race frequency with consequent breakdown of resistance in these cultivars. To combat the problem of resistance breakdown, pyramiding of resistance genes into different cultivars is being carried out. Pyramiding of resistance genes is now possible with molecular markers that are developed for individual genes. This report the gene for biotic stress such as bacterial blight, blast resistance, brown plant hoper genes identified and their corresponding molecular markers developed for breeding durable resistance into modern rice.