Monday, November 5, 2007
60-11
Genetics and Mapping of Powdery Mildew Resistance in North Carolina Wheat Germplasms.
Lilian Miranda1, Judd Maxwell2, Leandro Perugini2, Goran Srnic3, Ainong Shi2, Jeannette Lyerly2, Rene Navarro2, Christina Cowger2, David Marshall4, Gina Brown_Guedira2, James Kolmer5, Steven Leath6, and J. Paul Murphy7. (1) University of Georgia Experiment Station, University of Georgia, 1109 experiment street, Griffin, GA 30223, (2) North Carolina State University, North Carolina State University, 1243 Teakwood Pl, Raleigh, NC 27606, (3) Syngenta Seeds Inc., Pioneer, Via Giuseppina no. 39, Malagnino (Cremona), CR 26030, ITALY, (4) USDA-ARS, USDA-ARS, Raleigh, NC 27695-7616, (5) USDA-ARS Cereal Disease Lab, St. Paul, MN 55108, (6) Box 7643, USDA-ARS, North Carolina State University, 100 Patterson Hall, Raleigh, NC 27695-7643, (7) Box 7629, North Carolina State University, North Carolina State University, 840 Method Road Unit 3, Raleigh, NC 27695
Powdery mildew, caused by Blumeria graminis DC f. sp. tritici Em. Marchal, is a prevalent foliar disease of wheat (Triticum aestivum) in the eastern United States . In an effort to increase genetic diversity for disease resistance, North Carolina State University has released thirteen germplasm lines with powdery mildew resistance introgressed from diploid and tetraploid wheat relatives. The recurrent parent for all of these lines was the soft red winter wheat cultivar ‘Saluda’ and the donor parents were diploid and tetraploid A, D, AB, and AG genome accessions. Progress on genetic studies and phenotypic characterization is presented. Microsatellite (SSR) linkage maps were developed for the powdery mildew (Pm) genes in 7 of these lines. Among the Aegilops tauschii-derived lines (D genome), two novel Pm genes for chromosome 5DL were found in NC97BGTD7 and NC96BGTD3. Pm34, the NC97BGTD7 Pm gene, was mapped to the distal end of 5DL and it was flanked by SSRs Xbarc177 and Xbarc144. Pm35, on NC96BGTD3, was proximal to Pm34 and had Xcfd26 as the closest marker. The Pm gene on NC96BGTD1 was flanked by Xgwm111 and Xgdm88 on 7DS. Based on the linkage maps for 3 of the Triticum monococcum –derived lines (A genome), the Pm genes on NC96BGTA4 and NC96BGTA6 were assigned to chromosome 7AL and the Pm gene on NC96BGTA5 was assigned to 1AS. The NC96BGTA4 Pm gene was flanked by Xbarc292 and Xwmc525. The Pm gene on NC96BGTA6 showed no recombination with Xcfa2019 and was flanked by Xbarc121 and Xgwm332. The linkage map for the Pm gene on NC96BGTA5 suggests that this gene is either allelic or tightly linked to Pm3. A new Pm gene, Pm37, was reported for the T. timopheevi-derived line (AG genomes) NC99BGTAG11. Pm37 was assigned to chromosome 7AL and had Xwmc790 and Xgwm332 as flanking markers.