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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: Genomic selection in forage breeding: designing an estimation population

Authors
item Resende, Rosangela -
item Casler, Michael
item Resende, Marcos -

Submitted to: Plant and Animal Genome Conference
Publication Type: Abstract Only
Publication Acceptance Date: December 19, 2013
Publication Date: N/A

Technical Abstract: The benefits of genomic selection to livestock, crops and forest tree breeding can be extended to forage grasses and legumes. The main benefits expected are increased selection accuracy and reduced costs per unit of genotype evaluated and breeding cycle length. Aiming at designing a training population, deterministic equations were used to estimate the impact of sample size (N individuals), effective population size (Ne), number of markers per centimorgan (Ls per cM) and heritability (h2) on accuracy considering Panicum virgatum (switchgrass, genome size ~1,600 Mpb for ‘Alamo’ genotypes) as a model. Simulations were based on Ne = 50, 100 or 150, Ls = 0.3, 3, 6, 10 and 20 markers per cM, and N = 500, 2000, 6000 individuals phenotyped and genotyped. Trait heritability was considered as ranging from high (0.70) to very low (0.01). The selection method was based on individual selection. Taking the benchmark accuracy of traditional BLUP-based phenotypic selection (r=0.80) as a reference, accuracy for genomic selection was similar when h2 = 0.4, using 20 markers per cM, Ne = 50 and 6,000 individuals. As h2 increases, fewer individuals (= 2000) and fewer markers (10 per cM) are needed to achieve the same accuracy. Low heritability traits (= 0.1) can require 20,000 genotyped and phenotyped individuals, 20 markers per cM and Ne = 50. Considering the declining of genotyping costs, an expected reduction in generation time, and a potential increase in accuracy, genomic selection is a valuable new tool for use in forage improvement.

Last Modified: 10/22/2014
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