Investigating the impact of preselection on subsequent single-step genomic BLUP evaluation of preselected animals

Table 4 ssGBLUP performance, with different preselection types and intensities, all with a heritability of 0.1

Measure	Type and intensity of preselection
Measure	No preselection	High GPS	Very high GPS	High PAPS	Very high PAPS	High RPS	Very high RPS
Preselection accuracy^a	Not applicable	0.71 (0.69–0.73)	0.71 (0.69–0.73)	0.44 (0.42–0.46)	0.44 (0.42–0.46)	0.00 (0.00–0.00)	0.00 (0.00–0.00)
Subsequent selection accuracy^b	0.80 (0.78–0.82)	0.48 (0.44–0.52)	0.48 (0.44–0.52)	0.69 (0.67–0.71)	0.68 (0.66–0.70)	0.73 (0.71–0.75)	0.73 (0.73–0.73)
Absolute bias^c	0.01 (−0.01–0.03)	0.03 (0.01–0.05)	0.03 (0.01–0.05)	0.03 (0.01–0.05)	0.04 (0.02–0.06)	0.05 (0.01–0.09)	0.05 (0.01–0.09)
Dispersion bias^d	1.02 (1.00–1.04)	1.01 (0.95–1.07)	1.00 (0.94–1.06)	1.01 (0.99–1.03)	1.01 (0.97–1.05)	1.01 (0.97–1.05)	1.02 (0.98–1.06)
True realized genetic gain^e	1.38 (1.32–1.44)	1.26 (1.18–1.34)	1.24 (1.16–1.32)	1.11 (1.03–1.19)	1.00 (0.92–1.08)	0.58 (0.54–0.62)	0.39 (0.37–0.41)
Estimated realized genetic gain^f	1.36 (1.30–1.42)	1.28 (1.22–1.34)	1.26 (1.20–1.32)	1.12 (1.06–1.18)	1.01 (0.95–1.07)	0.58 (0.56–0.60)	0.37 (0.35–0.39)

Results shown only for the selection candidates in the most recent generation (i.e. generation 15), and the results are means over 10 replicates (and 95% confidence intervals)
Types of preselection: GPS genomic preselection; PAPS parent average preselection; RPS random preselection
Intensities of preselection: No preselection; high preselection - 10% of the male and 15% of the female selection candidates preselected; very high preselection - 5% of the male and 12.5% of the female selection candidates preselected
^aCorrelation between true and genomic estimated breeding values of all the selection candidates
^bCorrelation between true and genomic estimated breeding values of the preselected animals
^cDifference between average true breeding value and average genomic estimated breeding value of preselected animals, expressed in additive genetic standard deviation
^dCoefficient of regression of true on genomic estimated breeding values of the preselected animals
^eDifference between average true breeding value of subsequently selected animals and average true breeding value of their parents, expressed in additive genetic standard deviation
^fDifference between average genomic estimated breeding value of the subsequently selected animals and average genomic estimated breeding value of their parents, expressed in additive genetic standard deviation

ISSN: 1297-9686