How to dump genes from GenBank in GFF3 format?
Turns out you can just grab the GFF3 from the NCBI's FTP site!

ftp://ftp.ncbi.nlm.nih.gov/genomes/all/GCA/000/003/195/GCA_000003195.3_Sorghum_bicolor_NCBIv3/

See:


https://www.ncbi.nlm.nih.gov/genome/doc/ftpfaq/#files


Or "Access the data" on the right here:


https://www.ncbi.nlm.nih.gov/assembly/GCF_000003195.3