According to the Gregtech crops list here
http://wiki.feed-the-beast.com/Crops_(GregTech), the keywords of Tine are as follow: Shiny, Metal, Pine, Tin, Bush.
There are no crops that share Pine and Tin, but there are a few crops that share Shiny and Metal and Bush. First off, to help increase your chances of getting into metal crops... you're going to actually need a metal crop. Argentia is a T7 silver reed plant, Plumbilia is a T6 lead reed plant. Argentia shares more keywords with Tine and Coppon (Coppon shares 3 keywords with Tine, while being only 1 Tier above Tine. It made more sense for me to get to Tine this way, especially with the whole Copper/Tin thing that apparently exists.)
So, this all being said, you're best bet to get into metal crops is Plumbilia. Considering keywords and Tiers, Reeds & Netherwarts
should offer you a fairly decent chance at getting it, or better yet, Netherwards with Stickreed. You get to eliminate a few tiers of plants. Breed Plumbilia with itself to get a decent chance for Argentia. If you've been doing additional crop breeding before, and own a Slimeplant, try breeding that with Argentia for a decent chance at Coppon (which is T6, I might be wrong about plants being open to breeding down 2 levels of tiers.) End with Coppon with a Slime Plant (again, if you own one. I feel mutations happen more often when you breed with different plants.) That should likely be the best path to getting Tine.