Why don't you try it and report back?
Is there some reason why you want to use watercolor on a canvas rather than on watercolor paper?
Personally, I'm still looking for the perfect watercolor paper and trying to learn the behavior of the several types of paper that I currently have. I would expect that of the four combinations of wet/dry paper and wet/dry color, dry on dry would do the best on canvas and wet on wet is not likely to produce very good results. But trying it out yourself is the best way to find out.
Also, be aware that this forum is rather "slow", so you can't expect quick responses, or often any response right away.