Tabix is a program that is necessary to be able to index the gff file for upload and display in Jbrowse. However, getting a gff file viewable in jbrowse is a little more work than a bed file.
1. Sort your gff file by scaffold name and position. Typically this works like "sort -k1,1V -k4,5n file.gff >sorted_file.gff"
2. Zip your file with bgzip. As simple as "bgzip sorted_file.gff"
3. Index your zipped file with tabix. "tabix -p gff sorted_file.gff.gz"