[azakai]

It seems like it should be at pretty much the same speed, if an equal size amount of garlic plants were being attacked by MRSA. Doesn't matter if natural selection of human-guided selection does the culling.

I suppose it might be expensive to grow lots and lots of garlic plants and test them all for efficacy, though.

[mathattack]

I don't think it's correct to assume the speeds are equal. Genetic mutations propagate across viruses and plants at very different speeds.

[sthreet]

A generation of bacteria is way shorter lived than a generation of garlic. It would depend on how much the garlic was used though I'm pretty sure, though you might need to talk to an actual biologist for details.

Also, unless garlic defended itself from MRSA by killing it human guided selection would be better, what if the garlic is sneaky and figures out another way to survive that doesn't help humans.