NGHIÊN CỨU ĐƠN GEN CỦA CÁC DÒNG BỆNH ĐẠO ÔN TRÊN LÚA (Orysa sativa L.)

One hundred of fungal strains were isolated from Vietnam which were inoculated on 36 varieties of the International Rice Research Institute evaluating and identifying 23 genes resistant to blast. Results recorded with 5 genetic groups of blast. With 10 genes (Pik-m, Pi1, Pik-h, Pik, Pik-p, Pi7 (t), Pi9 (t), Piz-5, Pita (IRBLta-K1), and Pita (IRBLta-CT2) blast recorded in the Mekong Delta. Results screened with 100 local rice varieties and inoculated with 8 samples of blast. Results recorded 4 varieties reinfecting with races which existing on grain (OM7340, OM6161, OM8902, MNR3) and 4 remaining varieties did not affect the seedlings (OM6600, OM5756, OM7398, OM6162). When evaluating the toxicity of 8 disease samples on the indicator group 1 with 3 genes Pia, Pib were the highest infection with rate of 100%, gene Pi5 (t) were the highest infection in group 2. In group 3, the infection rate of genes Pi7 (t) were the highest, group 4 with Piz-t gene were the highest infection with rate of 37.5%. Group 5 has 2 genes Pita-2, Pi12 lost the complete resistance with 8 races of above fungi. Besides, there is still some genes which is still resistant validation as: Pish genes, Pii, Pi3, Pik-s, Pi1, Pik-h, Pik, Pita and Pi19 (t), special attention to Piz gene is completely resistant to the above fungi races. Demonstrate Piz gene is highly resistant validation to fungus group causing blast disease. It can use this gene for many works of breeding resistant to blast