High quality backlinks are not coming by an high PR backlink!
A high quality Backlink you can onlky get when the site which your backlink is posted have the niche related keywords in H1, H2 and H3 Title Tags.
Also the site must have niche related keywords as anchor textlinks to other related websites.
So its very useless to get an backlink on a catfood website when your content have fishfood.