Single-step BLUP with varying genotyping effort in open-pollinated Picea glauca

BLAISE RATCLIFFE; OMNIA GAMAL EL-DIEN; CAPPA EDUARDO PABLO; ILGA PORTH; JAROSLAV KLAPSE; CHARLES CHEN; YOUSRY A. EL-KASSABY

Genes|Genomes|Genetics

Genetics Society of America

Año: 2017 vol. 7 p. 935 - 942

2160-1836

Maximization of genetic gain in forest tree breeding programs is contingent on the accuracy of the predicted breeding values and precision of the estimated genetic parameters. We investigated the effect of the combined use of contemporary pedigree information and genomic relatedness estimates on the accuracy of predicted breeding values and precision of estimated genetic parameters as well as rankings of selection candidates using single-step genomic evaluation (HBLUP). In this study, two traits with diverse heritabilities (tree height and wood density) were assessed at various levels of family genotyping efforts (0, 25, 50, 75, 100%) from a population of white spruce (Picea glauca) consisting of 1,694 trees from 214 open-pollinated families, representing 43 provenances in Québec, Canada. The results revealed that HBLUP bivariate analysis is effective in reducing the known bias in heritability estimates of open-pollinated populations, as it exposes hidden relatedness, potential pedigree errors, and inbreeding. The addition of genomic information in the analysis considerably improved the accuracy in breeding value estimates by accounting for both Mendelian sampling and historical co-ancestry that were not captured by the contemporary pedigree alone. Increasing family genotyping efforts were associated with continuous improvement in model fit, precision of genetic parameters, and breeding value accuracy. Yet, improvements were observed even at minimal genotyping effort indicating that even modest genotyping effort is effective in improving genetic evaluation. The combined utilization of both pedigree and genomic information may be a cost-effective approach to increase accuracy of breeding values in forest tree breeding programs where shallow pedigrees and testing large populations are the norm.