Validation of Yield Component Traits Identified by Genome‐Wide Association Mapping in a tropical japonica × tropical japonica Rice Biparental Mapping Population

Abstract

© Crop Science Society of America. The Rice Diversity Panel 1 (RDP1) was developed for genome-wide association (GWA) studies to explore five rice (Oryza sativa L.) subpopulations (indica, aus, aromatic, temperate japonica, and tropical japonica). The RDP1 was evaluated for over 30 traits, including agronomic, panicle architecture, seed, and disease traits and genotyped with 700,000 single nucleotide polymorphisms (SNPs). Most rice grown in the southern United States is tropical japonica and thus the diversity in this subpopulation is interesting to U.S. breeders. Among the RDP1 tropical japonica accessions, ‘Estrela’ and ‘NSFTV199’ are both phenotypically and genotypically diverse, thus making them excellent parents for a biparental mapping population. The objectives were to (i) ascertain the GWA QTLs from the RDP1 GWA studies that overlapped with the QTLs uncovered in an Estrela × NSFTV199 tropical japonica recombinant inbred line (RIL) population evaluated for 15 yield traits, and (ii) identify known or novel genes potentially controlling specific yield component traits. The 256 RILs were genotyped with 132 simple sequence repeat markers and 70 QTLs were found. Perl scripts were developed for automatic identification of the underlying candidate genes in the GWA QTL regions. Approximately 100 GWA QTLs overlapped with 41 Estrela × NSFTV199 QTL (RIL QTL) regions and 47 known genes were identified. Two seed trait RIL QTLs with overlapping GWA QTLs were not associated with a known gene. Segregating SNPs in the overlapping GWA QTLs for RIL QTLs with high R2 values will be evaluated as potential DNA markers useful to breeding programs for the associated yield trait.