OsGASR9 positively regulates grain size and yield in rice (Oryza sativa)

•OsGASR9 transcripts were detected in various tissues, with the highest level in panicles.•Higher mRNA of OsGASR9 accumulated in young than in old panicles and spikelets.•OsGASR9 positively regulates grain size and weight, and increases the yield production in the NIP background.•OsGASR9 may regulate plant height, grain size and yield through GA pathway and could have an application value in breeding.