Most growers don't have the patience for hybridizing. As a flip side of the coin, daffodil bulbs will divide and increase. This is the most common way of increasing the number of bulbs. Many of the commercial growers use a method called, chipping, to reproduce bulbs. This is a method of mechanically splitting bulbs into anywhere from two to 32 pieces, and growing new bulbs from each segment, but that process is for a future article.
New varieties come from seeds only.
Each daffodil seed contains the potential for the introduction of a new daffodil variety. No two seeds will produce the same cultivar, even those from the same cross. Take a few minutes to read the information there, as well as the remainder of this article. Natural hybridizing does not occur that often in daffodils as they are not usually self pollenating. It does happen ever so often by stray bees, wasps, or other insects, but not often enough.