Originally Posted by Gabe15

Roots never form suckers, they only come from the corm.

As Tog pointed out, water suckers form from bits of corm and from chopped down plants because the shoots need to immediately start photosynthesizing themselves instead of acquiring photosynthate from the rest of the plant which has leaves. Water suckers can also form from old established mats, I suppose they occur from a complex coincidence of certain anatomical and environmental circumstances (such as how old the corm section its coming off of is, or how exposed to the sun it is etc..)

Keep in mind that whether or not a sucker is sword or water, they are genetically identical and one is not going to be overall better than another, there just may be some growth differences initially when young. Some studies have found differences in the first fruit bunch, and some have found none, I think it really depends on cultivar and environment, as do most results of this sort. TC plants are the ultimate water suckers, and they grow up just fine, in some cases outgrowing field separated suckers initially, but again, after the first generation is doesn't matter how they plant was propagated.