Thursday, June 23, 2016

What Is a Daylily? 5 - Hybridization 2

What Is a Daylily

Part 5
The Origins of the Garden Daylily
Part 2

In the previous installments to this series we have looked at the long evolutionary history of the genus Hemerocallis, the species of the genus and their relationships to each other, the daylily's place in the cultural history of Asia and the influences that may have had on the genus, and the early days of hybridizing, up to the late 1930's. Now I want to discuss this early phase of hybridizing and consider its repercussions on our modern daylilies.

Domestication has historically been a long process and the details for most domestication events are lost to us as they occurred in the distant past. However, most domestication has been a slow process that took place over fairly long periods of time. The daylily provides us with a remarkable view on how domestication can occur through hybridization of multiple species (though that is not how all domestication occurred - some occurred through the domestication of single species). In a little over a hundred years, we have seen a literal explosion of hybrid daylilies and we have seen a very fast advancement of visual variations within the flowers of the domestic population. It is truly remarkable, and I wonder if most people realize just how remarkable it is, or how fast it has occurred? I would say, from my perspective, that it has been like a bolt if lightening out of the clear blue.

Daylily hybridizers are to be congratulated on the remarkable work they have done to increase the colors, forms and patterns found in daylily flowers. It is a truly remarkable thing and one for which every hybridizer who has consistently pushed the envelope and brought us to this place should be congratulated and held in high esteem. I am endlessly amazed at the vast departure we have made from the flowers of the wild species in such a short period of time and I think, as Dr. Grant-Downton suggests in his paper A New Day Dawning: Hemerocallis (Daylily) as a Model Organism, that the daylily offers a unique and special window into the process of domestication. However, I am not sure that most daylily breeders actually understand what they have been doing in terms of domesticating a wild genus, nor how truly remarkable the speed at which it has occurred actually is. 

When we look at the early days of hybridization, as we did in the last installment of this series, we see something of the choices the early hybridizers made. It is important to understand that each choice we make influences the future directly. Each choice we make determines the nature of the genome that future hybridizers will have to work with. It influences the nature of the ever-evolving domestic gene pool. Selection - the choices we make at every stage - increases some traits and decreases others. That is really what selection is. It is artificial when we do that in captivity (our artificial gardens) and it can lead us to amazing places, but can also lead to cul-de-sacs that are hard to then get out of. Each selection we impose, as well each choice we make in the environments in which we grow and breed our plants, create impacts that will ripple into the future. Our choices literally change the nature of the genome, and it is so important to remember that we are doing so based on artificial parameters, not necessarily natural ones. 

Natural selection is vastly different than the artificial selection that we impose on domestic populations. Natural selection is aimed at survival and adaptation to changing environments, while artificial, captive selection (domestication) is based upon aesthetic and commercial concerns (utilitarian or monetary), often with a large dose of peer-pressure and group-think thrown in. That is not to criticize anyone, but simply to point out the non-natural influences that go into this process, especially with something like the modern daylily where there is really no utilitarian applications in the western world, as we see in something like wheat, corn (maize) or rice. In other words, we daylily breeders can be frivolous and ignore basic aspects of environment and survival by creating highly artificial environments and selecting for traits that nature would deselect. However, we must never forget that every choice we make influences the genome of our lines, and not just in our lifetime, but forever.

So let's look more closely at the early years of hybridizing.

In the early days, the hybridizers were working with a limited number of species and species clones. There were obviously no cultivars to turn to and so it all began by simply crossing the handful of available species with each other. Species such as H. lilioasphodelus (synonym H. flava, with the general common name lemon daylily), H. dumortierii, H. minor, H. middendorfii, H. fulva forma Europa, H. thunbergii, H. citrina, H. aurantiaca and H. aurantiaca 'Major', as well as a few other forms of fulva, composed the major gene pool from which the first hybrids were made. 

When we look at the records of those early hybrids, both in Europe and America, H. aurantiaca and 'Major' show up very frequently. I mentioned several of the reasons for this in the previous post. Among those is that it was available, it had large flowers (for the time, especially Major), it flowered near the time of Europa and the early-mid yellow species and it was much more fertile than the fulva clones available, especially Europa. Imported in the early 1890's, it was always noted for being marginally tender in cold regions and Stout even mentions that many of the hybrid offspring from aurantiaca and forma Major were also tender in cold regions, yet its appeal was such that it was used heavily anyhow and so is one of the central ancestors of many of our hybrid lines. 

That choice has resulted in the tenderness seen in many lines of modern daylilies, especially the evergreen lines, but also in some deciduous ("dormant") and 'semi-evergreen' cultivars that have had significant contribution from those aurantiaca-descended lines. Now I want to be very clear that I am NOT saying that all daylilies are tender, or even that all evergreens are tender. They are not, but some are and it is predominantly from aurantiaca and Major that this trait entered the hybrid gene pool. 

(As a side note, I would point out that I have witnessed deciduous ("dormant"), evergreen  and so-called 'semi-evergreen' cultivars, that while fully winter hardy, have low frost tolerance once they are growing in the spring, with late spring freezes causing significant damage to the growing foliage, and occasionally, the scapes and flowers as well. I have also witnessed this trait in some of the species such as the fulva complex (which I would consider to be more semi-evergreen than "dormant" or evergreen), but it is a trait found in aurantiaca as well. I do not suspect that 'frost-tolerance' and 'winter-hardiness/cold-tenderness' are the same thing, as many perfectly winter-hardy cultivars show high frost sensitivity. I wanted to be sure and mention this, because I rarely see the two things distinguished.)

Once we get to Stout, we see that he used aurantiaca and Major extensively in his early work and many of this foundational plants, such as Mikado, Theron and Vulcan, have this species in their immediate ancestry. Stout was interested in promoting the daylily as a plant for use in the south, especially in the near-tropics of Florida where few of the popular perennials could flourish. For that reason, Stout used aurantiaca heavily, crossing to hardier species, to attempt to produce hybrids that could flourish in both the north and the south. 

In some instances he succeeded, but in other instances, he introduced plants that were more suited to the south, while others were more suited to the north. He details this in his 1934 book Daylilies, listing some that work best for the north and some that work best for the south (pg. 100). Stout envisioned daylily cultivars that would be lovely garden perennials suitable for the conditions of Florida, but I wonder if he envisioned a world of shade cloth, drip irrigation, artificial soilless growing mediums, intensive feeding regimens and chemical spraying regimens? Of course, those more recent choices have had their own impacts.

To this very day, breeders are still crossing cold hardy northern lines with more cold tender southern lines to make plants that are all things for all areas and incorporate the best of both types. We are still seeing much the same results as Stout had in his work - partial success. It is not a bad attempt to make, and I also use this method from time to time, but it won't always work. Stout foresaw regional lines for the south and for the north, with some crossover. Crossing the two types creates a lot of intermediate plants that work in either setting, but may not be the most suited for either. Stout specifically mentions that minor, dumortierii and middendorfii are most suitable for the north and so are likely ancestral to some of the most cold hardy lines we have now. I would also point out that the fulva and citrina complexes show strong cold hardiness and probably have contributed that to northern, cold hardy lines, even though they will flourish in the deep south as well. 

In addition to aurantiaca, the species thunbergii, lilioasphodelus, and dumortierii were used quite frequently in the early hybridizer's programs. While Stout did not use citrina very much (he didn't care for it and says it has 'no garden value' in his book), others did use citrina quite a bit. Fulva was used by some hybridizers who were persistent, but it was Stout who really put the fulvas to great use. He made thousands of pollinations with Europa to generate a small number of seedlings that figured heavily in his own program and he made use of all the fulva clones available to him, but it was the importation of the pinkish-tinted fulvas, which would become known as forma rosea, that propelled the use of fulva to a cult amongst the early hybridizers. 

The importation of this form of fulva occurred in 1924 with three plants being received by Stout at the New York Botanical Garden from Kuling, China, which had been collected from the wild by Dr. Albert Steward. These plants had pinkish flowers and Stout saw the potential. He used these three plants extensively, crossing them with each other and to his own hybrid seedlings. He also sent divisions of these plants out to a handful of other breeders, amongst them Amos Perry of England and Elizabeth Nesmith, who was a friend of Stout and had gathered a large collection of the cultivars and species available at the time. In time, Nesmith made divisions of that rosea clone she had available to a few other daylily breeders and from there they made their way into commerce. When Stout found out, he introduced that clone as Rosalind in 1938. Four years previously, he had introduced Charmaine, which was a seedling from crossing the original collected rosea plants with each other. Charmaine was significantly cleaner and lighter pink, with a cleaner background color and rather paler buds than any of the original imported plants.

With the importation of the fulva forma rosea plants, the die was cast and modern daylilies began to evolve. By the nineteen-forties, no one was using the species clones much, and almost all breeding from that time forward has been crossing within the hybrid population. While we can say that this trait or that trait derive from this or that species, many of the modern traits and trait-combinations that we see in the modern daylilies likely exist because of the interaction of various traits from several of the species, as is common with later-generation hybrid populations. 

We often hear that colors such as pink, lavender and near-white all descend directly from fulva forma rosea, and that is for the most part probably true, but it likely isn't exclusively rosea that gave us these colors, as we know them in modern daylilies, or color-clarification genetics in general. I suspect that in time, the original pink cultivars that were directly descended from rosea interbreeding such as Charmaine were crossed with light flowered yellows with citrina in their heritage, especially the lightest colored clones of citrina and their descendants, and it is through the combination of the carotenoid reduction factors of BOTH fulva rosea and the palest citrina clones that our lightest colored pink, lavender and near-white flowers likely descend. 

A good example of this type of early blending may be the cultivar Parfait, which is a pinkish bicolor with a very citrina-like flower. Parfait is in the background of many modern lines, but in no way can I discount the influence and importance of fulva rosea. Rosea likely is as important to the modern daylily as is Europa, the aurantiaca and the yellow species that were used early on, and may even be more important, as it was used so heavily once it and its descendants became available. It is also the species form that was used the latest, still being used by some breeders after the nineteen-forties. When Amos Perry received rosea from Stout, he discontinued all his previous lines and started over with rosea, for example. Such choices determine the future. The heavy use of aurantiaca gives us tenderness and evergreen foliage to this day. The heavy use of rosea gives us the many pastel shades of color that are so popular in the modern daylily, but it may also have given us other things as well.

Anyone familiar with the fulva complex will have noted that they do not have the darkest green foliage, nor is their foliage alway particularly attractive. As well, they are what I would colloquially refer to as "natural semi-evergreen". That is, they are deciduous ("dormant") in the north and more evergreen in the south, and they can be severely damaged by a late spring freeze once they are actively growing. Anyone who has grown any of the fulva rosea types such as Rosalind will probably have noted that it has less-than-attractive foliage, perhaps more than some of the other fulva forms. There is no trait more than the ugly foliage of most near-white cultivars that convinces me of their descent from fulva forma rosea, even more so than their pale, carotenoid-reduced flower color. 

When we look at the pink, lavender and near-white cultivars, we see the results of choices very clearly - the early desire for these colors and the subsequent striving for ever more clean and clear versions of these colors has often seen the overall plant and especially the foliage garner some neglect. That is not to blame anyone. I am glad that the breeders of the past made such an effort to create these clean, beautiful tones, but we can see the direct results of narrow focus and choices in a great many of them. Now we have those clean colors, but we may need to work on making more attractive plants with those lovely flowers.

We often speak about the dark green foliage that is preferred by most daylily people, but we may not realize where it derives. When we look at the species, we see this tone in such species as citrina and dumortierii. When we see a pink, lavender or near white, red, purple or orange flowered cultivar with that lovely dark green foliage, it is likely that citrina, dumortierii or one of the other dark-green foliaged species is in the background in addition to the fulvas that likely contributed the flower color. While many yellow cultivars may have no descent from any of the fulva clones, many do. Anyone who has ever crossed two red or purple daylilies and then bloomed out a yellow seedling from the cross has seen the type of segregation for genes that could allow there to be self-colored yellow cultivars with fulva in their ancestry.

So is it certain that pink, purple, red or orange ONLY come from the fulvas? No. While it is likely that fulva complex clones are the only source for these color genes, we can never be completely certain, because many of the yellow species may carry anthocyanic genetics that are not expressed in the phenotype or are not visible to our limited range of color perception. It is possible that some of the yellow species have knock-out genes that eliminate anthocyanin from the flower, but the genes for the production of anthocyanin are still present and may be retrieved in the phenotype by segregating out the gene(s) that inhibit them in later generation hybrids. I personally have wondered if the bluish-lavender eyes that are so popular in the daylily world might not be derived from yellows like citrina though such gene segregation in the hybrid populations. When we look at some yellow flowers under ultraviolet lighting, we see a distinct bluish eye on many of them. 

Branching and bud count clearly did not derive from the fulva group, nor from species such as dumortierii. Species such as citrina and multiflora are the most likely origins of these traits. Miniatures likely descend in part from minor and nana as well as dumortierii. The species range across the bloom season, and so those traits will descend from various species clones. Interestingly, the fulva clones are spread throughout the bloom season. Very early flowering may descend from dumortierii, but other early types could be involved as well. One trait that was actively bred out was rhizomatous growth - spreading by root runners. This trait is undesirable in a garden setting, but may well have applications in estate planting or for erosion control, yet it is now missing from the vast majority of cultivars due to the choices of the past. All of these traits we have discussed, and especially the combining of many of these traits in specific combinations that has occurred since, is due to the choices made by the early hybridizers who were seeking to make a better and more beautiful garden flower. 

Once the species were no longer being used, the mold was set in place, and any traits that had been deselected from the hybrid population were gone and were not being brought back in by going back to the species. In addition, for the nineteen-forties on, the focus of breeders became more and more narrow. The focus became wide, round petals and a round/ruffled, "bagel" form, a height of preferably no more than twenty-four inches and self-colors. Tall daylilies and thin petals were seen to be "too specie-like". Bands and eyes were seen to be "too fulva-like". Rhizomatous growth was anathema. Bicolors and eyed cultivars were occasionally introduced, as were thin petalled spider types. Occasionally a tall cultivar was introduced. Stout continued to introduce interesting cultivars up until his death, with his last introductions coming shortly after his death, in 1960. 

For the most part though, from the nineteen-forties forward, round, wide-petalled, self-colored, twenty-four inch daylilies were the standard aim until things started to shift again and people began to look back to the origins of the daylilies, the species and early cultivars, in the nineteen-nineties and early two-thousands. Even since then, very few have tried going back to the species. Brian Mahieu and Gil Stelter are notable exceptions who have gone back to the species looking for greater vigor, cold-hardiness and thinner, spider and unusual forms. For anyone interested in the development of the modern garden daylily from the nineteen-forties forward, I suggest reading the many articles on the subject in the back issues of the AHS Journal (available to AHS members at the member's portal) and as documented in the book A Passion for Daylilies by Sydney Eddison.

I often wonder what has been lost to us in the rush to the 24", round, self-colored modern daylily. What might the early cultivars and the species have carried that was deselected with the narrow focus of later years? With the focus on self-colors, could patterns have occurred earlier if eyes had been more popular? A narrow focus on one trait does often lead to faster success and extreme expression in regard to that one trait, but it can also exclude other interesting traits. I often refer to an over-focus on one or two traits as a 'fetish'. We see this in almost all animal and plant breeding communities. A handful of traits becomes elevated above all others to the point that all else is ignored, not even seen, in the rush to accentuate the fetish traits. These fetishes often fall along the lines of 'color' or 'form'. In the rush to elevate these fetishes though, the more important underlying traits such as vigor, plant traits, fertility, foliage traits etc are often forgotten or ignored.

In addition to what may have been lost from the original species that went into the development of the modern daylilies, we now have access to a few species and species clones that the original breeders did not have, and of course, we still have some access to those original species (some more than others). Such species as H. hakuunensis, H. sempervirens. H. vespertina and newer clones of fulva may carry traits we have never even yet imagined and they have made little or no impact on the modern hybrid genome to date. In addition to the fetishes and narrowed focus, there are some superstitions that may inhibit the discovery of new traits. We often hear to "never cross reds with yellows". It is true that this cross can create a first generation that lack clarity of red color, but what can be found through this cross that we haven't yet noticed in our fetish for "clear red" in the first generation from any cross? A good example of what might be found, if we are open-minded enough to think outside our narrow, self-imposed boxes, is the Substantial Evidence line that Richard Norris developed by crossing Lights of Detroit (a yellow) with When I Dream (a red). In addition to giving us many very wonderfully flat cultivars, this cross also led to the amazing, color-changing, closest-to-blue-we've-yet-seen, Pigment of Imagination. 

Along with the fetish for self-colors, another fetish that developed along side it was for flowers that did not fade or change color throughout the day, which of course is a nice trait, but there can be "good fade" too. How many times was the plant that could have led to a flower like Pigment of Imagination culled because its color "didn't hold" throughout the day? If Richard hadn't noticed the blue, midday phase of Pigment, would he have culled it if he only saw the morning cough-syrup magenta version and the evening flesh with darker edge version? The current sculpting forms have likely emerged many times only to be culled as "flaws". How many interesting unusual forms and spider-precursors have been culled from round and ruffled bagel lines? I am not saying it is bad to focus, but we should also check our focus occasionally and ask if we are overlooking other interesting flower traits or important plant traits.

Another area where little to no focus has ever been given is foliage. The Hemerocallis are closely related to Hosta, and it is my observation that all the basic traits that have given rise to the array of Hosta foliage colors is also present in the Hemerocallis genome, but no one has made foliage their 'fetish', to focus on it and bring these traits to any highly selected state. While there has been little selection for foliage variations, such as chartreuse foliage or bluish foliage, there has been a tiny bit of selection toward dark green foliage, though in general, foliage has been neglected, as anyone can see by looking over the less-than-lovely foliage of so many daylily cultivars. Beyond beautiful foliage or foliage colors, what about foliage form? There are significant variations in the genus and the hybrids, but no one seems to have made any effort to expand form. I think if anyone did focus on foliage form we could see wide foliage, wavy foliage, thin and grassy foliage brought up to new levels. Could we make giant, broad leaves with pie-crusting and wavy ruffles? The hints of these traits are there in certain plants and are just waiting for someone to care enough to bother to make the selection, but to date, no one has.

So what is a daylily? It is the result of hybridizing various Hemerocallis species, then breeding those hybrids together and selecting for various traits. It is an artificial garden flower selected to match the desires and interests of the breeders who have worked with it, and shaped by the conditions in which it has been grown. It is not just one thing. It is different in the south than in the north. It is different for a breeder of spiders than for a breeder of bagel forms. It is the culmination of every choice that has been made by every breeder who has worked with it and shaped its destiny. But can it be more? Can we continue to redefine what a daylily is? Are their traits waiting to be discovered or focused on that could open new doors for this remarkable garden plant? I think there is.

In this last post in this series, I want to point out that different choices may have resulted in different outcomes. The plants we have are the direct results of the choices applied. What if the earliest hybridizers had used less of one species and more of another? What if we occasionally dip back into the species and older cultivars, making different choices than those who used them previously? What if we cross to newly obtained species that those who went before us never had access to? Each choice we make, at every stage, determines the plants we have.

We often hear that we shouldn't look to remake the daylily, and simply be content with the choices of the past and only focus on the directions that other have already focused on, seeking to keep increasing the traits they cared about and only use the newest and 'latest and greatest' cultivars, with the implication that they are the most advanced and thus 'the best', but are they necessarily? If our only concern is the traits that others have been focusing on, then that may be true, but if we want to look further afield, then we should look wherever our bliss takes us.

 It is the cumulative result of the choices made at each point along the way that has brought us to where we are now. It is not inevitable, nor set in stone, and anyone interested in making something new, different or uniquely their own may want to make their own lines, perhaps even going far back to the earliest cultivars or even the species and make different choices than were made in the past. As a parable, a vehicle with only one wheel is unstable. The more wheels we have, the more stable our vehicle, and if the wheel we have is damaged or has inherent weaknesses, we made need to remake that wheel or even make a new wheel, lest were wreck and burn. There are hundreds, perhaps thousands of daylily breeders and over 70,000 registered cultivars and the species. I want to stress that I am not saying anyone satisfied with their program should make any changes. I am happy for there to be breeders focused on the traits that have been consistently popular. They continue to push that envelope further, but there is more than one envelope, more than one trait, and the entire daylily genome is not defined by only flower traits. In fact, there is much more to the daylily than just the flower. 

With so many breeders, there is room for many different programs and many different areas of focus. I beg newcomers to not just follow the pack or follow the leader, but to take a serious look at the Hemerocallis and find unique, interesting and valuable areas of focus that have been neglected to date. There is way more to the daylily than a handful of fetishized flower traits. We need to remember that. Survival for millions of years through a changing climate gave us the species that were combined to make our modern garden daylily. The early hybridizers made choices that laid the foundation that the later hybridizers built on, narrowing and winnow that gene pool into the modern flowers we now grow through their choices. Each choice we now make determines what we leave for the future. I hope you will remember to choose wisely.