Basic Concept

The GRiSP Global Rice Phenotyping Network is a research consortium for multi-site, multi-trait rice phenomics, aiming at gene discovery to enhance molecular breeding. It uses agreed-on diversity panels of about 300 accessions used by all partners to conduct Genome-Wide Association Studies (GWAS). The basic concept is illustrated in the diagram below.

GWAS on diversity panels has the advantages of providing information on (1) genome loci linked to agronomically useful traits, and at the same time (2) allelic diversity (polymorphisms) present on those loci. The approach therefore enables not only the discovery of candidate genes, but also genetic materials that can be potentially used as donors for useful alleles of the genes.

The pitfalls of this approach are (1) the possibility of false positives in GWAS resulting from phyllogenetic structure within the panel - for example, a distinct evolutionary branch of the species may carry a common trait and a common gene but they are not physiologically linked - and (2) the difficulty to phenotype traits on very diverse materials that may differ strongly in crop duration and morphology.

Consequently the GWAS approach adopted by the network needs to be followed up by validation studies before the discoveries can be applied in molecular breeding.