Development of Scab Resistant Soft Red Winter Wheat Germplasm Using Marker-Assisted Selection.
Jose Costa1, Erin Wenger1, Leila Al-Tukhaim1, Neely Gal-Edd1, David Van Sanford2, and Gina Brown-Guedira3. (1) University of Maryland, Plant Breeding and Genetics NRSL, 2102 Plant Sciences Building, College Park, MD 20742-4452, (2) Plant & Soil Sciences Dept., University of Kentucky, Univ. of Kentucky, 327 Plant Science Bldg., Lexington, KY 40546-0312, (3) USDA-ARS, Raleigh, NC 27695
Scab of wheat, caused by Fusarium graminearum, is a disease that periodically strikes the US mid-Atlantic region. Breeding for resistance is an effective measure of disease control. The objective of this study was to develop scab resistant wheat germplasm adapted to the US mid-Atlantic region using MAS. The cultivar McCormick, was used in a backcross program with Ning7840. Scab resistant germplasm were bred using an accelerated backcross scheme developed to incorporate scab resistance the 3BS and 5A QTLs from Ning7840. Two rounds of backcrossing were completed using McCormick as the female parent. Progenies from the first round of backcrossing were selected for the presence of the Ning7840 3BS and 5A scab resistance alleles, and for a high background of McCormick alleles. Two BC1F1s had over 60% McCormick background. 782 BC2F1s were produced in a second round of backcrossing. Of these BC2F1's, 386 were planted individually in Maryland and the rest in Kentucky and screened with 3BS, 5A and 2DL-linked markers. In Maryland, 56 BC2F1s were selected. Seed from ten selected BC2F1s will be grown in 2007 (94 seeds from each BC2F1 each= 940 plants total) and further screened with 3BS, 5AS, and 2DL markers to select those homozygous resistant. We expect approximately 16 to be homozygous. Additionally, we plan to derive near-isogenic lines from an BC2F2 population to identify the effect of each QTL on scab resistance, agronomic and quality traits. We anticipate having a small amount of seed of selected BC2F3s, containing the Ning7840 alleles in the McCormick background, available for distribution to SRWW breeders for crossing in the fall of 2008.