GWAS reveals novel QTLs associated with panicle architecture traits in US long‐grain rice

Understanding the variability of panicle architecture‐related traits is important to enhance rice ( Oryza sativa L.) improvement. The present study evaluated 208 diverse rice lines of southern rice breeding programs for panicle length (PL), panicle weight (PW), and thousand grain weight (GW). The rice lines were studied in the field following randomized complete block design in 2021 and 2023 in Beaumont, TX. The lines were genotyped using the LSU500 Agriplex SNP markers panel to identify the genomic regions associated with panicle architecture traits. A positive correlation was observed between GW with PW and PL in 2023 and PL with PW in both years. The phenotypic data exhibited a normal distribution in both years. A total of 19 quantitative trait loci (QTLs) associated with PL, PW, and GW were detected through genome‐wide association studies using four statistical models (fixed and random model circulating probability unification, Bayesian‐information and linkage‐disequilibrium iteratively nested keyway, mixed linear model, and general linear model). The identified QTLs are located on chromosomes 1, 2, 4, 6, 7, 8, 9, 10, 11, and 12. The highest number of QTL was identified for GW. Novel pleiotropic QTL, qPW7 and qPL7 on chromosome 7, were associated with the “LSU_diversity_652” SNP marker. Candidates’ gene Os07g0112700 or OsENODL19 associated with the marker encodes a cupredoxin domain‐containing protein. RiceXPro revealed that this gene is highly expressed in reproductive organs, early grain, embryo, and endosperm development stages in rice. Published RNA‐seq data showed the higher expression of the Os07g0112700 in the flag leaf, flower buds, and mature seeds. The identified marker and gene can be utilized in rice breeding programs.