An alternative isIf you need the access to the root folder, then you have to permit root to log in in /etc/ssh/sshd_config and use the user root in filezilla however this is not recommended for server security reasons.
https://wiki.filezilla-project.org/Howto#SFTP_using_SSH2:_Key_based_authenticationAn alternative is
PermitRootLogin without-password
This would allow you to login as root with an ssh key, but not with a password.
Unfortunately, now that I look at FileZilla, it doesn't appear to support ssh keys. Maybe I'm missing the option...?
Starting with version 3.0.8, FileZilla has a built-in key management page in the settings dialog.