The Hosta Book

What little I remember about genetics from my highschool biology class would lead me to expect that if a hybridizer wanted to produce variegated seedlings, the logical thing to do would be to cross a variegated pollen parent with a variegated pod parent.  Even if variegation was a recessive trait, at least some of the progeny should be variegated.

Well, that’s not the way it works. For reasons I won’t go into here (there is an abundance of information on the subject in past issues of The Hosta Journal), in order to produce variegated seedlings reliably, you have to start with a pod parent that has streaked foliage. It’s not the only way, but it is by far the easiest.

When used for breeding, a streaked mother plant will produce a reasonable percentage of streaked and variegated seedlings, like the one below.  When making crosses, the streaked plant must be used as the pod parent. Using its pollen on an unstreaked variety will not produce variegated or streaked seedlings. The pollen parent will affect all of the other characteristics of the offspring, but will not have any effect on variegation.

For those not familiar with streaking in hostas, it is a form of variegation that produces irregular patterns of white, yellow, green or blue throughout the leaf. While useful for breeding, the plants are also quite striking in the garden. Streaking is an unstable form of variegation, meaning that the patterns are constantly changing, with each leaf being different.

Being unstable also means that the plants can loose the streaking in time if they are not maintained. As the plant matures, it tends to stabilize, or revert to a more stable form. When this happens, the leaves on one or more of the new divisions that arise as the plant multiplies may be a solid color, or it may show a stable edge or center variegation pattern. In the picture above, you can see that on the newer leaves, the plant seems to be moving toward an edge variegation. These more stable forms are favored by the plant and will dominate and eventually the streaking will be lost.  This can be prevented by dividing the plant and removing the more stable forms as they arise.

While the streaked forms are unusual, and the streaking itself is probably attractive for the gardener, for the hybridizer, the stable, variegated forms are generally the objective.