Breeding for Rust Resistance in Daylilies: Part 9

Breeding for Rust Resistance in Daylilies: Part 9

In this post we will pick up where the last one left off and look at some tips and pointers I have for hobbyists, collectors and breeders who wish to pay any attention at all to the problem of rust in daylilies or who wish to pursue, actively or passively, a program of breeding for rust resistance in daylilies.

A Challenge and Invitation: Part 2

So what are my suggestions for those who would try?

Know your area and what might work for you. Obviously, if you are in the north, you can’t actively breed for rust resistance, because you are not going to consistently have rust in order to do so. If you get rust every year, but only in the fall, you still don’t have the conditions to do a full-on resistance program as would someone in the south with spring and fall rust, but if you are getting rust consistently most every fall, you can still make strides toward more resistant seedlings and the removal of the most susceptible seedlings from your population. This is a big thing and not to be underestimated, just because it is not the most extreme project that can be pursued by more southern located breeders.

However, with that said, if you are in the south and have rust nearly year round, if you spray, you can’t resistance breed, and if you only discontinue spraying in the fall, then you are creating an artificial condition that doesn’t allow you to take advantage of your location fully. That is fine, if that is your choice, but you still will not be getting the full advantage that your location offers. To take fullest advantage of near year round rust, you have to actually be exposing your plants to that nearly continuous rust cycle. Be warned, you will possibly loose plants, especially if you are in the most southern extremes of the country, but those that survive and show resistance under those extreme conditions will form the backbone of a true resistance-breeding project.

Educate yourself about cultivars. To resistance breed, actively or passively, you need to know what cultivars are already showing resistance and use them. To do this in your own collection, you must allow some rust exposure and you must evaluate your plants. Just one evaluation in a season is not really sufficient. You need to do an evaluation every week or two while rust is active to get a feel for how a given cultivar progresses through the season. While that season won’t represent ‘proof’ of a given resistance level, it will give you an indicator to work from. Another thing you can do is to talk to others who have been working with rust to find out about known resistant cultivars. You may even be able to get someone with knowledge of resistant cultivars to look over your accession list in order to point out what you have that is known to be resistant or susceptible.

To find other resistant cultivars, you need to look at the information that is out there. While there isn’t much, there is some: surveys, university evaluations, and anecdotal. Don’t discount the later. One of the most important things you can do is to talk to people, read threads on message boards, and see what people have to say about various cultivars. Ask questions! When you begin to hear the name of a given cultivar mentioned over and over by numerous people in many different locations as being resistant, take note. That one might actually be! Further, if that same cultivar also shows up on surveys and university evaluations as having resistance, it may turn out to be very usable for you.

Every report will not be found to be the same for you, but if even a few do, that will give you a basis to work from.  Finally, even if you aren’t breeding for resistance at all, you can at least know a few cultivars thought to have resistance to tell others, and if you happen to be a seller, it would be nice if you know that some of the cultivars you offer have been observed to have resistance or are susceptible so you can answer clients questions about either thing.

For breeders, listen to the reports of people growing your cultivars. If you can’t (or won’t) experience rust in your garden, this can be a valuable source of basic information to work from. I realize that these reports are only ‘anecdotes’ but they are a place to start, and if by chance you hear from several people that this or that cultivar has been resistant, there is a good chance that it is (or at least will have some level of resistance that may be usable for breeding). In time, enough anecdotes can be indicative of actual resistance. They at least give you a basis for further testing in your own garden.

Breeders please do publicize your observations and the received (anecdotal) reports of your customers. This is a point I think is important to make. Your anecdotal evidence, when added with that of others, is important. If you have observed a cultivar showing resistance or immunity or susceptibility, tolerance or lack of tolerance to rust, then those observations matter, and if by chance you have observed the given results repeatedly over the course of some years, it has even more weight. Now I do think it is important that you not treat your observations as absolutes. You don’t want to say, “I have proven that so-and-so is resistant or immune or whatever because it has been so in my garden for x# of years”. That is too definite, but to say that, “So-and-so has shown resistance or immunity or susceptibility, etc. in my garden (and in X# of my customers gardens, etc) during X# of years”, is perfectly acceptable, because you are making no absolute claims. You are not saying something ‘is’ this or that, but that is ‘has performed as’ during a given time in your garden (or other gardens you have been told about) for a given time period. 

You should also then report variations, so that if a given cultivar was strongly resistant for three years, then had a susceptible year (possibly another strain of rust?) then had a resistant year, you are not making absolute claims, but rather are offering your observations. If you want, you can also add a disclaimer that your observations are yours alone and may not reflect performance in other gardens.  Be clear, but pass on what you have observed. Just because the topic is ‘rust’ doesn’t mean it should be treated any differently than any other trait we select for. After all, many of you report your observations of say bud count and branching, even though we know they may not be the same in another garden in a different environment...

I don’t know of anyone in the daylily world who is afraid to make ‘claims’ or share their experience of things like branching, foliage type, fertility, breeding influences of a given cultivar on pattern, color, emo, or any other flower traits. Rust is not any different. The long wait for “proof” along with the scientific bludgeon of ‘unscientific’ has resulted in far too many hobbyists keeping quite about their experiences with rust and their observations of given cultivars. Imagine what the daylily world would be like if we treated every trait we select for with that same delicacy.

Now, I have to admit that I understand fully why so many clamor for ‘proof’ and why researchers have been skeptical. The claims of ‘rust resistance’ could easily be exploited for financial gain by the unscrupulous. It would be very easy for someone to have popped up and claimed rust resistant strains with no proof and have been claiming a premium for that claimed resistance. It is to the credit of the daylily world and a reflection of the honesty of the great people in the daylily world that this didn’t happen.

I would also add that I don’t see ‘rust resistance’ as being a trait to command a special premium. I think it is just another trait that daylily breeders need to be selecting for, where they can. I do think we need to be more open about our experiences, preface that they are merely our experiences and share those, letting go of fear of censure or attack as well as the prospect of our observations being ‘trade secrets’ that can eventually enrich us. We need to be sharing our knowledge and working to improve the plant we all love.

Be realistic about what you can do, but try to do something, no matter how small. Not every breeding program needs to be focused on the ultimate goal of 100% immune cultivars. That would be a worthy goal and a great thing to work toward, but to make that your expectation will likely lead to disappointment rather than a garden fully of nothing but rust immune seedlings. It seems inevitable that in time some researcher(s) may discover the gene(s) that offer both resistance and even full immunity to rust and from that, may be able to create cultivars (or even true breeding lines) of cultivars from those genes, but hobbyists, out in the trenches breeding by sight and experience, do not have the advantage of labs and funding, so we must proceed from a point that, while less controlled, can still give good and useable results, and even the best lab identification of a given gene offering rust immunity or resistance probably won’t apply to every strain of rust. So in that regard, whether in the lab or simply in your garden, all things are fairly equal in the sense that there is likely to always be a race against new strains of rust that make our old resistance genes obsolete, partially or totally. This has certainly proven to be the case in the examples of rust and rust resistance in other species.

For that reason, I don’t think the notion of waiting for the experts to ‘fix it’ is all that viable, and further, if someone does come along and introduce a ‘proven rust resistant’ strain, you can always breed those into your own lines. In effect, you are making preparations for the day when such ‘proven’ lines might become available. Just remember that no line of ‘proven resistant’ plants, mine, yours or those from a lab, are likely to remain that way forever, in the face of the constant evolution of new strains of rust. For this reason, I think a more realistic goal, and one fraught with far fewer pitfalls and less heartbreak, is to focus on good to high resistance with high tolerance to rust and the combining of many genes for resistance in the hopes of weathering the onslaught of many different strains of rust over time. Yet while this is my realistic approach, you should find yours.

At any rate, doing almost anything is better than doing nothing. What is realistic in the Far North is not realistic in the Deep South, and vice-versa. The important point I want to make here is that if we set the bar too high (a common failing in most places and endeavors), we almost invariably set ourselves up for failure. As I have pointed out in this series before, most gardeners and breeders aren’t too bothered by a bit of rust. It is the heavy rust coverage of the low resistance/highly susceptible cultivars as well as its negative impact on performance (and in some case survivability) that creates the most distress and the most severe problems we encounter with rust. In my view, the most realistic goal is to begin to move the genome of the genus toward resistance and away from susceptibility, and we can each make a contribution in whatever way we can, at whatever level is suitable to our location, situation, inclination and interest.

Remember that selection for rust resistance is just another form of selection, another trait amongst many you select for already. I can’t stress this enough. Yes, rust may have been a big, scary freak-out when it first emerged, and it may create the same response when you first have it in your garden, but by now we know that (except in a few very southerly locations) rust is not the end of the road. So now, rust is just another ‘problem’ many of us deal with, just like low bud counts, melting pigments, ugly foliage, etc. Consequently, resistance to rust is now a factor to select for, as any other. Don’t get too extreme (unless you just really want to or are in a situation where you can) and do what you always do for any other trait - make selections.

While that will not be considered a ‘resistance-breeding program’, you will be making your own small contribution and thus making a difference, even if only in a small way by simply removing the most rust susceptible. At the very least, you will be paying attention to your own plants and learning what shows the desired tendencies in your own garden. Beyond that, you can choose any level of project you want to pursue, setting your goals as low or high as you want. You just need to arm yourself with information and be prepared to make an extreme effort should you choose an extreme goal. In the end, whether simple or extreme, your goals will revolve around selection.

Have confidence! Nothing beats confidence for getting you through uncertainties. It is true for anything we do. Don’t have unrealistic confidence, but do know that you can increase the levels of resistance in your breeding projects. There will be naysayers who want to convince you that you can’t succeed. They could have any number or reasons. Those reasons aren’t important. What is important is that you stay focused on what you have chosen to do within your own breeding program. Remember, there are no ‘daylily police’ out there to force you to follow their dictates in your breeding program. If you let peer-pressure derail you from your goals, that is not really the fault of those others.

It will not be uncommon to encounter other hobbyists who want you to believe that resistance breeding is just beyond hobbyists abilities, way too hard to accomplish, something that can’t be done, there is no ‘proof’ for and just not important - just spray and don’t talk about silly pie-in-the-sky things like “resistance breeding”. On the other hand, you will encounter science types who are just as eager to derail your efforts. Now don’t get me wrong, I consider myself an amateur scientist and I work closely with PhDs and have for many years, but scientists, like all people, run the gambit from gleeful and light-hearted to dour and negative. That is human nature, and (even if they don’t all believe it) scientists are just humans too, with all the foibles and failings that implies. However, scientists will have a special set of tools for discouraging you.

First, they can use big words, talk over your head and generally make you feel stupid. They can use their favored bludgeon of declaring your efforts to be ’unscientific’. This can make you doubt yourself and your efforts, but you need to be very clear on what ‘unscientific’, as they use it, really means. While there may be a variety of meanings, it is generally meant that what you are doing doesn’t meet current scientific standards that would be used in a university or industry setting. What it doesn’t mean is that you can’t still be applying science in a more basic sense. You can use the scientific method without meeting current peer-review standards. After all, if your goal is merely to breed as a hobbyist, no matter how lofty the goal, why do you possibly need to meet peer-review standards?

The scientific method has four major points or procedures:

1. Formulation of a Question
2. Background research and formulation of a hypothesis
3. Testing the hypothesis through experimentation
4. Analysis of results

While these four procedures alone will not merit a project as ‘scientific’ by current industry and professional standards, if you are using them in your work, it is not ‘unscientific’, regardless of what anyone tells you. You don’t have to be preparing for peer-review in order to use the scientific method in your breeding program. Your goal is to increase the levels of rust resistance in your seedlings, not to ‘prove’ that it can be done to peer-review standards.

Finally, I would again point out that our ancestors managed to accomplish a great deal without any scientific understanding - they turned teosinte grass into corn (maize), wild triticum grasses into wheat, bitter and inedible wild potatoes into the modern staple, jungle fowl into chickens and wolves into dogs, just to name a few. What we seek to do in increasing the level of resistance to rust in our daylilies (a resistance that already exists within the overall daylily genome) is not nearly as radical or extraordinary as what our ancestors achieved before us, and we have much better tools at our disposal to achieve this.

Have confidence! There is already resistance to rust within some daylilies. The genes are there. We don’t have to find the genes - we already have some indication where to look. We don’t have to genetically engineer resistance - it exists in some plants within the population. All we actually have to do is identify it, concentrate it and compare it against various strains of rust. Not any one individual has to do all these things either. It is a job for the entire community of daylily breeders to do, so no one of us must carry the entire weight. Remember that the worst thing that can happen is failure and it is important to remember that if you do fail at increasing the level of rust resistance in your program the world won’t end, markets won’t collapse, civilizations won’t fall. Don’t get so serious that you give yourself an ulcer over a flower. While we daylily breeders don’t like to admit it, if worse comes to worst…there are other flowers…or we can learn to ignore some rust.

Finally, I would like to point out that belief creates your reality, in the sense that, if you believe you can’t select for resistance, then you will never try and it will thus be a self-fulfilling prophecy. What you never attempt, you will never achieve!

In the next installment we will look at some daylily family lines known to show resistance and a random listing of some cultivars that have shown resistance.