A novel QTL GSE3.1 regulates grain size and weight in rice

Grain size is a crucial agronomic trait that directly determines grain yield. To elucidate molecular mechanisms of grain size control will help breeders develop high-yield varieties. In this study, we report a novel quantitative trait locus (QTL) GRAIN SIZE AND WEIGHT ON CHROMOSOME 3 ( GSE3.1 ) for grain size and weight in rice, which encodes a TONNEAU1-Recruiting Motif family (TRM) protein and positively regulates grain size by promoting cell division. In addition, the GSE3.1 allele from Daligeng (DLG) significantly increases grain size and weight, and further improves grain yield in field plot trials. Thus, our findings demonstrate the molecular mechanism of GSE3.1 in grain size and weight control, suggesting this gene could be a promising target for breeding high-yield varieties in rice.