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United States Department of Agriculture

Agricultural Research Service

Research Project: REDESIGNING FORAGE GERMPLASM AND PRODUCTION SYSTEMS FOR EFFICIENCY, PROFIT, AND SUSTAINABILITY OF DAIRY FARMS Title: Paternity Testing, a Poor Man’s Marker Assisted Breeding Strategy to Increase Selection Gains in Outbred Forage Species

Author
item RIDAY, HEATHCLIFFE

Submitted to: International Symposium of Molecular Breeding of Forage Turf
Publication Type: Proceedings
Publication Acceptance Date: January 20, 2010
Publication Date: March 15, 2010
Citation: Riday, H. 2010. Paternity Testing, a Poor Man’s Marker Assisted Breeding Strategy to Increase Selection Gains in Outbred Forage Species. In: Proceedings of The 6th International Symposium of Molecular Breeding of Forage Turf, 15-19 March 2010, Buenos Aires, Argentina. p. 119.

Technical Abstract: Many methods to incorporate molecular markers into breeding programs have been proposed. Most existing marker assisted selection strategies use selection based on molecular marker linkage to achieve selection gains. Such strategies are often prohibitively expensive in forage breeding (Riday, 2007). Presented is a new paradigm in marker use; instead of using markers to define linkage, markers are used to define paternity first. In many forage breeding programs polycrosses are made with maternal identity retained. However, it is prohibitive to make crosses in which paternal identity is retained. Enter markers, which can be used to identify paternity. Paternity testing theory and software programs already exist. Incorporating paternity testing in breeding programs requires three components: 1) tissue from all individuals entering selection nurseries; 2) tissue from all potential parents of individuals entering selection nurseries; and 3) individually phenotyped plants in selection nurseries. Standard halfsib family selection is practiced on maternal families, capturing ¼ additive variance. An additional ¼ additive variance is captured by selecting on paternal families. Using this method greater selection gains can be achieved using far fewer families; making paternity testing more cost effective than regular halfsib family selection despite the additional cost to accomplish the molecular marker work. Paternity testing also acts as a spring board for many other possibilities to enhance a breeder’s efforts (e.g. with individual plant phenotypes and full parental knowledge, the selection nursery can also serve as a large complex mapping population). A proof of concept study in red clover (Trifolium pratense) is presented. Paternity of progeny from multiple 96-plant polycrosses were determined at high rates using 14 SSR markers multiplexed into two PCR reactions. Paternity testing doubled the power to predict progeny phenotypes based on parental breeding values, demonstrating feasibility and utility of this marker assisted selection strategy. Riday, H. 2007. Marker assisted selection in legumes. Lotus Newsletter 137(3):102.

Last Modified: 7/28/2014
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