Genome-Wide Association Mapping in Rice for Yield and Grain Quality

Rice is one of the most important crops in the world accounting for a large proportion of the human caloric consumption. Uruguay is one of the largest worldwide rice exporter and is the third country with the largest average grain yield. However, breeding for new varieties with even larger grain yield and good grain quality has been a challenge. This resulted in that more than 90% of the cultivated area in Uruguay is planted with only two old varieties from the early 90s. To overcome yield plateau a molecular breeding approach was implemented in the national rice breeding program with two complementary strategies: Genome-wide association mapping (GWAS) and genomic selection (GS). QTL mapping was performed for grain quality and yield in a diverse panel. A total of 665 advanced inbred lines from both indica and japonica sub-species from the breeding program were genotyped by genotyping-by sequencing (GBS) to obtain close to 150K SNPs. Lines were phenotyped for grain yield, flowering time, plant height and several grain quality parameters in three years. GWAS was performed using mixed models to correct for population structure. QTL results are discussed in this work and will be used to introgress genomic regions through a marker assisted selection program.