벼 단인자 계통과 우량 벼품종의 도열병 저항성 분석을 통한 안정 저항성 유전자 탐색

Identification of Stable Resistance Genes Based on Resistance Evaluation to Blast for Monogenic Lines and Leading Japonica Varieties in Rice

Rice is the most important staple food in Korea. Rice blast, caused by Magnaporthe oryzae, is one of the most devastating diseasesin the rice-growing world and in Korea. Eighteen major blast resistance genes were screened in 33 leading Korean japonica varieties using44 DNA markers. The 33 leading japonica varieties are cultivated in 659,642 ha (90.4%), and a variety of Samkwang is cultivated widelyon a nation-wide scale. Four resistance genes, Pia, Pib, Pi19, and Pb1, were detected in 10-21 varieties, and the R-genes of Pii, Pish, Pita/Pita-2,Piz/Piz-t, Pi35, and Pi65(t), were present in 2-5 varieties. Five R-genes, Pit, Pi5, Pi9, pi21, and Pi40, were not detected in the Korean japonicarice varieties. A total of six varieties, two mid-late flowering varieties, Ilmi and Saeilmi, a medium flowering variety Gopum; and three earlyflowering varieties Jopyeong, Haedamssal, and Haedeul; were resistant to blast nursery screening over 12 years. A variety of Gopum harboredalleles for Piz/Piz-t, and three early flowering varieties, Jopyeong, Haedamssal, and Haedeul, had extensive loci of the multiple-gene familyPiz/Piz-t, Pi9, and Pi40 on chromosome 6. Two mid-late flowering varieties, Ilmi and Saeilmi, harbored the Pita-2 gene, and Gopum hadPita. In the japonica rice breeding program, an effective means for enhancing stable resistance to blast will be to introduce resistance genesPit, Pi5, Pi9, pi21 and Pi40 which were not identified in Korean japonica rice varieties, and resistance genes Pita/Pita-2, Piz-t/Piz-5, to 2-3R genes among and Pi20 that showed stable resistance in monogenic IRBL lines.