BREEDING FOR REBLOOM & IMPROVED FOLIAGE
Dr. Joseph Halinar

Question: Joe, I would like to breed for rebloom in zones 5 through 7. Are there particular daylilies (Dips & Tets) that I should collect in order to experiment with? One of my other goals is to improve daylily foliage so that it is "prettier" and less disease prone during the growing season. Do you have any recommendations in regards to improvements in foliage?

Thank you very much for taking the time to write articles for the Region 11 magazine this year. Should you have any other thoughts regarding hybridizing, please feel free to tell us about them. Take care, Jack

Answer - improved rebloom: Jack, First, let me say that it is always a pleasure to write articles and help novice and beginning hybridizers. The way I see it, some of today's novice hybridizers will be tomorrow's big named hybridizers. There is a lot of interest in daylily hybridizing, but there is only so much room at the top of the pile.

Many people hybridize purely for there own enjoyment while others are more serious. Regardless of where your interest lies it's always desirable to have some good knowledge of what you are doing. In that regard I hope that I can contribute what little I can to make daylily hybridizing more enjoyable to those who want to give it a try.

As to your question, it is difficult for me to give you a specific answer. It cannot be stated that if you use this-and-this plant you will get what you want. Rather, let me give you some guidelines that I think you can use for many other traits besides the ones you listed, but I'll try to use them as an example.

Whenever you look at a trait that interests you, you have to look at the whole germplasm pool and see how much variation is present. You can't breed for a trait unless you can find some variation within the germplasm pool that you can use. For example, the first daylilies to be used in hybridizing over a hundred years ago were yellow or orange colored. The earliest hybridizers couldn't breed for white, red, purple and pastel colors because those colors weren't available at the time. If you want to breed for rebloom in zones 5 to 7 then you will need some daylilies that will rebloom under those conditions.

Fortunately, there are a lot of daylilies that will rebloom. I seriously doubt that a southern hybridizer could introduce a daylily today that didn't rebloom and have it be commercially successful.

The question is, will it rebloom under your conditions? There is only one way to answer that question, and that is by growing daylilies under your conditions and testing them for rebloom. This is the general approach that you have to apply to what ever trait you are interested in - grow out daylilies and select those that have the traits you are interested in. You also need to remember that a desirable trait may be hidden in a recessive state in a plant you are interested in using, so examine the parentage, if at all possible, to see if it might carry the desired trait in a recessive state.

Your next task is to try to understand the trait you are interested in. Is it a simple trait or complex traits that can be broken down into smaller components? Can you figure out its inheritance?

In regard to rebloom there are probably several different genetic forms of rebloom. The rebloom found in Stella De Oro is probably different then the rebloom found in most of the Florida bred hybrids. Many of the newest Florida bred daylilies will re-bloom three or even four times under the proper conditions. However, they will rarely rebloom at all for me here in Oregon. You will really have to grow them under your conditions and see which ones rebloom for you. You can not assume that if you use parents that rebloom well in Florida that they will produce seedlings that will rebloom under your conditions.

Rebloom is a complex trait, but it tends to act like a recessive trait as far as I can tell. Thus, if you cross Florida bred rebloomers and grow them in a southern climate, then you shouldn't have many problems getting seedlings that rebloom. Your goal is to try to duplicate that under your conditions.

When making crosses use parents that rebloom under your conditions and then keep selecting for those seedlings that exhibit rebloom as your hybridizing program progresses. You may have to grow out some very large populations of seedlings to get progenies that rebloom and have the other desired traits you are interested in.

The rebloom potential of Stella De Oro, for example, is very difficult to recover. Some Stella De Oro seedlings will rebloom, but most either will not rebloom, or if they do rebloom the second bloom comes after a very long break. What you have to do is keep looking for those seedlings that show some re-bloom potential and keep intermating them. Eventually you will get a higher percentage of seedlings exhibiting rebloom and the rebloom will become more like the continuous bloom of Stella De Oro. It becomes difficult to select for rebloom and for all the other desirable traits as those seedling that rebloom may not have the other desirable traits and those plants that have the other desirable traits may not rebloom.

If your goal is to market re-blooming daylilies to a northern market, then your approach is going to be different then if you want to sell to a southern market. If you want a northern plant then I would suggest you look at using Happy Returns and Rosy Returns as they already have good rebloom. They are easier to work with in getting the genetic pastels and anthocyanidin pigmented colors that are popular. Cross them to some of Elizabeth Salters wide eyed cultivars. If you are looking at large flowered tetraploids, introductions from Pat Stamile and Dan Trimmer would be good choices. In particular consider using their deciduous daylilies. After that you will have to just keep selecting those plants that exhibit rebloom.

Answer - Improved Foliage

If you look at daylilies you really do not see a lot of variation in foliage. Daylily foliage may vary in size, but from a distance it's hard to pick out any great distinctions in foliage, as compared to, say, hostas. However, if you look carefully you will see a fair amount of subtle variation and you can make use of this variation.

Most people buy daylilies based on the flower traits and more or less accept the foliage that comes with the plant. As a hybridizer you should pay some attention to foliage. Most of the selection will be what can be called negative selection where you are selecting against a trait rather then actively selecting for a trait. For daylilies most of the attention will probably center on disease resistance.

During the early stages of your hybridizing program select against those daylilies that exhibit a tendency toward leaf scorch or rust or are otherwise unattractive. Later on as you get more and more seedlings that approach what you are looking for also pay careful attention to the foliage and start selecting those plants that not only have the desired flower traits but also have the nicest foliage. Then, when you make the final selections for what seedlings you will name and introduce, not only select those seedlings that have the flower traits you like, but also make sure they have good foliage and that the foliage doesn't distract from the flower. There is no excuse, for example, for introducing a plant with exceptional beauty but with foliage that is highly susceptible to leaf scorch.

The one area where selection for foliage is needed the most is the appearance of the foliage during the early spring when the daylilies are starting active growth, but the weather is still not favorable for daylilies. Many daylilies look terrible in the early spring, but improve as the weather warms up and turns into summer. As a general rule daylilies with deciduous foliage look better in the early spring then the non-deciduous daylilies.

Sometimes when I look at my daylilies in the early spring I wonder why I am growing them because of the appearance of the foliage. Later on they grow out of this ratty stage and by the time they bloom the poor foliage of early spring is a past memory that doesn't get a lot of attention as we get excited about the flowers that are blooming.

There are two factors you should consider when looking at foliage in the early spring - spring sickness and resistance to inclement weather.

I'm not sure how much resistance there is to spring sickness in daylilies. Several years ago I grew a bunch of seedlings under conditions that were very favorable to spring sickness and the vast majority of seedlings showed some degree of spring sickness, but there were others that were totally unaffected. Spring sickness is probably a fungus disease caused by a common fungus that is active during cool and wet weather and is promoted by high quantities of organic matter and nitrogen levels. As a general rule you should give serious consideration to whether or not you want to use daylilies in your hybridizing program that show susceptibility to spring sickness.

Daylily foliage can be quite unattractive during the early spring due to alternating freezing, cold rains and windy weather beating down the foliage. However, many daylilies stand up well and you should make observations of which daylilies hold up and consider using them in your hybridizing program. I know we can argue the merits or lack of for growing non-deciduous daylilies in a northern garden with cold winters, but one significant reason for growing deciduous daylilies is that their foliage generally looks much better in the early spring then does the foliage of non-deciduous daylilies.

During the spring periodically examine your daylily seedlings and the named cultivars you plan on using. Take notes on what the foliage looks like to use later when you start making crosses. If two plants are equally desirable parents consider using the one with the better foliage if they differ in their foliage traits.

Daylily hybridizers often pay too much attention to the flower and neglect the total plant. You are heading in the right direction with your concern for foliage, but you need to go even further and breed for the total plant. Look at not only the flowers and the foliage but also the root system - bred for the total plant.