SMALLER REFERENCE POPULATIONS
The size and structure of the reference population also has an impact on the development of GS. When populations are large, with well-known performance, as in dairy cattle, the prediction of future values is more accurate. Or, in the plant sector, the sizes of the reference populations are smaller. Initially, the high cost of genotyping could also be an obstacle to GS deployment. But today, prices are affordable, as Philippe Moreau, scientific director of the Seeds Division at Euralis, explains : “The genotyping of an individual on tens of thousands of markers costs between 10 and 80 €”. These genotyping techniques are also used on many plant species, whose genomes have been sequenced.
AN INTEREST IN QUANTITATIVE CHARACTERS
The biology of the species and the characters studied also influence the selection method used. When traits are linked to major genes, marker assisted selection (MAS) may be sufficient, as in the vegetable sector. For its part, genomic selection (GS) is particularly adapted to polygenic traits, which are governed by numerous low-effect genes. For Philippe Moreau, in field crops, this method has an interest in quantitative traits, such as yield, early maturity, tolerance to various stresses, including drought. The GS is all the more appropriate when the phenotyping of certain traits is expensive or difficult to implement.
AN ECONOMIC INTEREST
In the implementation of the GS, the economic aspect remains one of the major issues, related to the size of the company, the research budget allocated to the species… Nevertheless, Philippe Moreau believes that in the future, the GS should be generalized, with however differences of methods between channels and species, and even if “the impacts in terms of genetic gain or gain of efficiency are to be relativised and to appreciate species by species”.
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Feeding on phenotypic observations, the SG reinforces the predictive power of genetics markers.