U.S. flagAn official website of the United States government
                    Here's how you know **Official websites use .gov**
                            
                            A **.gov** website belongs to an official government organization in the United States.
 **Secure .gov websites use HTTPS**
                            
                            A **lock** (                            
                              A locked padlock                                                      
                            
                            ) or **https://** means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.


Menu Agricultural Research Service
						
                    U.S. DEPARTMENT OF AGRICULTURE
 Dairy Forage Research: Madison, WI
 close



    Research

                    Research Projects
                                    Publications
                                    Collaborations
                                    News
                People

                    Staff Listing
                                    CareersSearch small
                    Search
            
            ARS Home
                                About ARS
                                Contact Us




ARS Home Midwest Area Madison, Wisconsin U.S. Dairy Forage Research Center Dairy Forage Research Research Publications at this Location





- ARS National Programs
- Search for a scientific manuscript
- Search for a research project
- ARS Software
- Programs and Projects
- Collaborations
- Subjects of Investigation
- Publications

Title:   Author  item
                                            Riday, Heathcliffe
  Submitted to: North American Alfalfa Improvement Conference
                                    Publication Type: Abstract Only
                                    Publication Acceptance Date: 6/25/2010
                                    Publication  Date: N/A
                                    Citation: N/AInterpretive Summary:
                                Technical Abstract: Many linkage and linkage-disequilibrium based marker assisted selection (MAS) methodologies have been proposed. To achieve success, most require mapping populations and/or very high marker genome coverage. Presented is a MAS scheme that requires no mapping populations or known linkage group configuration. This method can be used at very low marker genome coverage. This MAS requires: 1) individually phenotyped plants, 2) co-dominant markers, and 3) known progeny maternal or paternal parentage at a halfsib level. Knowledge of both maternal and paternal parentage increases potential gains. In diploid systems, each progeny in a halfsib family can receive either one (uninformative) or two (informative) possible alleles from its halfsib parent. In informative cases within each halfsib family, the ‘good’ and ‘bad’ allele is determined based on individual breeding nursery progeny plant phenotypes. Individually, markers may appear to provide no linkage information; however, if a collective average rating for each progeny across all markers scored is determined (e.g. ‘good’ = 3; uninformative = 2; ‘bad = 1), useful information can be derived.  Since the approach is linkage based, markers even distally located from a QTL on the same linkage group can provide information. Efficacy of the system is demonstrated using population C584-Y-07 presented in poster presentation ‘Part 1’ (Riday, 2010) along with known progeny maternity and molecular marker inferred paternity, individual progeny phenotypes, and 11 SSR markers. A simple 200 permutation validation approach was used to demonstrate selection gains, with 80% of progeny used in estimation or marker ranking sets, which in turn were used to select within the 20% validation sets (Riday, 2010). Selection gains were observed within maternal but not paternal halfsib families (Fig. 1). This is likely due to larger maternal family sizes (~23) compared to paternal family sizes (~5). Individually, none of the 11 SSR showed significant linkage. Maternal halfsib family selection gains were estimated equivalent to a ~20% r2 QTL. The one drawback of this system is that for each parent only 1⁄4 of the additive s2 is selected on.


Return to top


Connect with ARS Sign up


ARS Home
                            USDA.gov
                            Plain Writing
                            Policies & Links
                            Civil Rights Statements
                            FOIA
                            Accessibility Statement
                            Privacy Policy
                            Non-Discrimination Statement
                            Quality of Information
                            USA.gov
                            WhiteHouse.gov