Clermont-Ferrand, France, 2013 International Workshop on Wheat Genomic Selection USEFULNESS OF GENOME-WIDE PREDICTION IN WHEAT BREEDING PROGRAMMES Gilles Charmet1, Eric Storlie2 1 INRA-UBP, UMR GDEC, 5 chemin de Beaulieu 63100 Clermont-Ferrand, FRANCE Colorado States University, Soil and Crop Science, Fort Collins, Colorado 80523, USA 2 Submitted for: oral presentation / poster (choose one) Selected session : oral session number or poster session Contact email address: gilles.charmet@clermont.inra.fr Dear Author, when submitting your abstract you are kindly requested to write it directly into this sample document and also by filling the form on the website. Upload the Word document as well when submitting your abstract online. Please kindly note that abstracts submitted in any other way cannot be accepted. The article must be not more than 1 page long. pt. 10 With the expected development of thousands of molecular markers in most crops, the marker-assisted selection theory has recently shifted from the use of a few markers targeted in QTL regions (or derived from candidate genes) to the use of many more markers covering the whole genome. Provided that a sufficient level of linkage disequilibrium exists between the markers used for genotyping and the true genes underlying QTLs for complex traits, these genome wide markers can be used to predict the true breeding value [1]. To be useful for breeding purposes, the accuracy of this Genome Estimate of Breeding Value (GEBV) should not be worse than the estimation based on phenotype, which is not always the best predictor of Breeding Value, particularly in the presence of GxE interactions. Moreover, since GEBV allows shorter selection cycles, an overall improvement of genetic progress per time unit is expected. [2]. We present a case study using DArT markers on the INRA wheat breeding programme, in an attempt to implement whole genome selection as an alternative to phenotypic selection. This investigation assesses different models – Pedigree BLUP, Ridge Regression BLUP, Bayesian Ridge Regression and Bayesian Lasso – ability to predict either simulated or real data (yield in a multisite, multi-annual network). The prediction coefficients obtained when the target population is a random sample (i.e. cross-validation) of the data are of the same magnitude of those reported in the literature. However, when the target population is a subset of genotypes studied in a given year (out of 10), the prediction quality is much lower. However, from a practical point of view, the ranking of (best) genotypes is more important than the prediction accuracy. Again the goodness of fit of best genotypes ranking is highly variable from year to year. Implication of results for practical implementation of genomic prediction in breeding programmes is discussed. 1. Meuwissen THE, Hayes B, Goddard ME (2001) Prediction of total genetic value using genome-wide dense marker maps; Genetics 157:1819-1829 2.Heffner EL, Sorrells ME, Jannink JL (2009) Genomic Selection for Crop Improvement. Crop Science 49:1-12