Submitted to: International Fusarium Workshop
Publication Type: Abstract Only
Publication Acceptance Date: December 11, 2004
Publication Date: December 11, 2004
Citation: Garvin, D.F., Blankenheim, Z. 2004. Development of wheat lines near-isogenic for diverse scab resistance QTLs for comparative genetic and genomic analysis [abstract]. Proceedings of the 2nd International Symposium on Fusarium Head Blight. p. 50. Technical Abstract: Extensive efforts have been directed at identifying novel sources of Fusarium head blight (FHB) resistance for wheat improvement. In many instances reportedly unique FHB resistance quantitative trait loci (QTLs) have been mapped to different chromosome locations both in a diverse range of common wheat genotypes and in related species but have not yet been introgressed into hard red spring wheat (HRSW). To continue improving FHB resistance in HRSW, it is imperative 1) that new FHB resistance QTL from wheat and its relatives be validated for their effectiveness in HRSW backgrounds, 2) that the efficacy of reported markers for unique QTLs be tested, and 3) that validated QTLs be incorporated by breeding programs. Otherwise the fruits of FHB resistance mapping will not be fully realized and future improvements in FHB resistance will slow. In 2001, we initiated a program to use marker-assisted backcrossing to individually introgress five FHB resistance QTL from diverse germplasm sources into three different FHB-susceptible HRSW backgrounds (Norm, Wheaton, Apogee). The initial QTLs selected included two from Sumai 3 (on chromosome arms 3BS and 5AS) to serve as reference QTLs, one from the soft red winter wheat Freedom (chromosome arm 2AS), one from the Brazilian wheat Frontana (chromosome arm 3AL), and one from wild emmer, (chromosome arm 3AS). Our goal is to develop BC4-derived near-isogenic lines (NILs) that are principally HRSW in genome composition but possess one of the five different QTLs (QTL-NILs). To date we have completed QTL-NIL development for three QTLs in Apogee and will have equivalent QTL-NILs completed in Norm and Wheaton in 2005. These lines will be subjected to comparative FHB resistance evaluations to determine which of the new introgressed QTLs confer resistance in HRSW backgrounds and the level of resistance each QTL confers. This is intended to be an ongoing endeavor to incorporate new FHB resistance QTL into HRSW as they are identified. The QTL-NILs that harbor new FHB resistance QTLs will be available to HRSW breeding programs. Further, there are many additional scientific benefits to be gleaned from these lines. For instance, the QTL-NILs will be used to quantify the effects of gene pyramiding, to examine the molecular basis of host-pathogen interactions, and to explore the biological basis of differences between type I and type II resistance.