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United States Department of Agriculture

Agricultural Research Service

Title: Marker-Assisted Selection in Eastern Soft Winter Wheat

Author
item Brown-Guedira, Gina

Submitted to: Eastern Wheat Workers and Southern Small Grain Workers Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: August 20, 2007
Publication Date: August 20, 2007
Citation: Brown Guedira, G.L. 2007. Marker-Assisted Selection in Eastern Soft Winter Wheat. Eastern Wheat Workers and Southern Small Grain Workers Proceedings.

Interpretive Summary: Soft winter wheat breeders in the eastern United States have been quick to adopt marker-assisted selection (MAS) as a tool for developing improved cultivars. The Eastern Regional Small Grains Genotyping Lab at Raleigh, NC has ongoing collaborative projects on MAS with most public programs in the region. Marker-assisted selection is being done for numerous genes in soft wheat breeding populations. Scab resistance is clearly the priority trait with 75% of all MAS data from the genotyping lab being for selection of FHB resistance QTL. The resistance QTL on 3BS is being selected in the majority of populations. In addition, QTL on 5AS and 2DL are undergoing selection in various populations in the region. The ease with which MAS for different genes can be done in Eastern wheat populations varies. Genes for which the currently available markers worked well across populations included: FHB resistance QTL on 3BS, 5AS and 2DL, Bvd2, Bvd3, Sr36, Sr24/Lr24, Lr21, H9, H13, Pch1, PinAm, and the pre-harvest sprouting tolerance QTL located on chromosome 2B. The rye-specific marker Scm9 has been effective in detecting the 1RS.1AL and 1RS.1BL translocations in different genetic backgrounds. Although a number of programs in the region are selecting the VPM segment having Yr17/Lr37/Sr38, we have found the Ventriup-Ln2 STS primer pair can give false-positives, although the marker works well for MAS when polymorphic. The most effect strategy for MAS will depend somewhat on the resources of the breeding program in balancing appropriate population sizes and number of crosses. The MAS samples sent to the Eastern Genotyping Lab are from plants at various stages of inbreeding ie. F2, F3, F4 or later. Not applying MAS until later generations has not been a very efficient strategy since the frequency of recovering target genotypes is low. Marker-assisted selection of three-way and backcross F1 plants is very efficient and increases the frequency of desirable alleles by 50%. MAS can then be done on the F2 or F2:3 progeny to eliminate of plants that are non-carriers of target gene(s).

Technical Abstract: Soft winter wheat breeders in the eastern United States have been quick to adopt marker-assisted selection (MAS) as a tool for developing improved cultivars. The Eastern Regional Small Grains Genotyping Lab at Raleigh, NC has ongoing collaborative projects on MAS with most public programs in the region. Marker-assisted selection is being done for numerous genes in soft wheat breeding populations. Scab resistance is clearly the priority trait with 75% of all MAS data from the genotyping lab being for selection of FHB resistance QTL. The resistance QTL on 3BS is being selected in the majority of populations. In addition, QTL on 5AS and 2DL are undergoing selection in various populations in the region. The ease with which MAS for different genes can be done in Eastern wheat populations varies. Genes for which the currently available markers worked well across populations included: FHB resistance QTL on 3BS, 5AS and 2DL, Bvd2, Bvd3, Sr36, Sr24/Lr24, Lr21, H9, H13, Pch1, PinAm, and the pre-harvest sprouting tolerance QTL located on chromosome 2B. The rye-specific marker Scm9 has been effective in detecting the 1RS.1AL and 1RS.1BL translocations in different genetic backgrounds. Although a number of programs in the region are selecting the VPM segment having Yr17/Lr37/Sr38, we have found the Ventriup-Ln2 STS primer pair can give false-positives, although the marker works well for MAS when polymorphic. The most effect strategy for MAS will depend somewhat on the resources of the breeding program in balancing appropriate population sizes and number of crosses. The MAS samples sent to the Eastern Genotyping Lab are from plants at various stages of inbreeding ie. F2, F3, F4 or later. Not applying MAS until later generations has not been a very efficient strategy since the frequency of recovering target genotypes is low. Marker-assisted selection of three-way and backcross F1 plants is very efficient and increases the frequency of desirable alleles by 50%. MAS can then be done on the F2 or F2:3 progeny to eliminate of plants that are non-carriers of target gene(s).

Last Modified: 8/21/2014
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