Genetic Variation and Association Mapping of Oil and Protein Content in Rice

Protein and oil content are important for breeding improved nutritional quality of rice. In this study, 135 rice accessions of diverse origin were genotyped using 232 SSR markers to identify marker–trait associations with oil and protein content in rice. Analysis of population structure revealed four subgroups in the population. Linkage disequilibrium (LD) patterns and distributions are of fundamental importance for genome-wide mapping associations. The mean r² value for all intra-chromosomal loci pairs was 0.0915. LD between linked markers decreased with distance. Marker–trait associations were investigated using the unified mixed-model approach, considering both population structure (Q) and kinship (K). In total, 167 marker–trait associations were identified using 232 different SSR markers covering 12 chromosomes. The results suggest that association mapping in rice is a viable alternative to quantitative trait loci mapping, the results from this association mapping study will be the basis for improving rice quality.