Submitted to: Plant and Animal Genome Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 11/1/2002
Publication Date: 1/11/2003
Citation: MCCLUNG,A.M., SHANK,A.R., MARCHETTI,M.A., JIA,Y., BORMANS,C., PARK,W.D., FJELLSTROM,R.G., PEDIGREE AND DNA MARKER ANALYSIS OF BLAST RESISTANCE GENES IN US RICE GERMPLASM, PLANT AND ANIMAL GENOME CONFERENCE PROCEEDINGS, 2003. p. 153.
Technical Abstract: Blast resistance genes have been effectively used in southern US rice germplasm to reduce crop losses from this serious disease threat. Historical records indicate the most common blast resistance genes in USA rice germplasm are Pi-z and Pi-ks in medium grain and Pi-kh and Pi-ta2 in long grain varieties, with the recent addition of Pi-b in long grain varieties. We report the spectrum of predominant blast races found in the US that confer an avirulent reaction with each of these five resistance genes, as well as the less common Pi-i, Pi-kLeah, and the pi-d resistance genes. Through pedigree information and specific blast race inoculation tests, we have identified the introduction, presence, and lineage of these five major blast genes in US germplasm from their origins to recently released varieties. We have further analyzed SSR markers linked with each of these five genes and gene specific primers amplifying the Pi-b and Pi-ta resistance genes to study associations between genetic markers and the presence of blast resistance genes. Our results indicate that most of the markers linked to these resistance genes display novel haplotypes compared with germplasm not carrying these genes. Markers found closest to the resistance genes usually had the strongest association with resistance. Different alleles at the Pi-k locus, being Pi-kh, Pk-ks, and Pi-kLeah, have unique marker haplotypes. Resistance marker alleles were found in indica varieties not carrying the Pi-ta resistance gene, indicating a reduced association between markers and the Pi-ta gene in some germplasm.