ARTHUR F. EVANS
Gravette, Arkansas
In the early eighties, when I first became interested in polyploid lilies, the scarcity of breeding stock was only equaled by the scarcity of knowledge in how to use them.
Fortunately, that has now changed to the point that keen and persistent amateurs can now get their hands on some really marvelous hybridizing tools. In the early nineties, knowledge and the available polyploid gene pool have expanded to the point that the
greatest limitation to progress may well be the scope of one’s imagination.
Polyploidy confers some interesting and valuable advantages to the genus Lilium, such as stiffer stems and thicker petals for better weather resistance, stronger root systems for better nutrition and drought tolerance, and, of course, greater genetic variability which will release a cornucopia of fresh novelties in all manifestations of
lily genetics. The most important advance may be in growability.
Have you been disappointed by the performance and early disappearance of cultivars specifically bred and produced for the cut flower market? Me, too! My greatest gardening pleasure is to walk among the myriad colors, forms, and fragrances of my lilies over a long season, without a sprayer in my hand. I want lilies that can “take
a licking and keep on ticking,” to borrow a phrase, year after year. The time of the lily as a true garden perennial is nearer than ever, and polyploidy should advance our progress by decades.
Please do not infer from my enthusiasm for polyploid breeding that I only use triploids and tetraploids, or that polyploids will make diploids obsolete. I don’t and they won’t. To paraphrase a long time Canadian hybridizer, Mrs. Jean Erickson, gardeners don’t care how many genes a lily wears. She is quite correct. If a polyploid cultivar or polyploids, in general, are not obviously superior to available diploids as garden plants, they will not predominate in the lily gardens of the future. Compared to our ideal of the perfect garden lily, most present day polyploids must be considered rather primitive, particularly in form and color, though less so in vigor and growability.
Another very important reason that diploids and diploid breeding will continue to be essential is that they contain important genetic characteristics which can be brought into the polyploid gene pool through the mechanism of (diploid x tetraploid) which yields triploid seedlings. Some professional hybridizers, notably Ed McRae,
suspect that triploids rather than tetraploids will make the better of the polyploid plants for commercial production. As more of our older cultivars such as the venerable L. tigrinum var. splendens, ‘Schellenbaum’, ‘Red Velvet’, ‘Thunderbolt’, and ‘Zigeunerliebe’ are discovered to be triploids, we must realize they were selected for
introduction because of superior plant characteristics and growability long before we knew “how many genes they wore.”
As the N.A.L.S. Seed Exchange shows, a lot more amateurs are now trying their hands at polyploid breeding. By all means, go for it! The future of hybridizing better garden lilies is mostly in the hands of amateurs. The bottom line is still the bottom line, and amateurs are the ones with the time, space, and means to support such a
labor of love. Garden lilies will never be as profitable as the cutting and forcing types, so we cannot realistically expect commercial hybridizers to cater to our needs. To my way of thinking, the role of the large commercial growers should be to do what they do best, that is, to use their high-tech means of production to provide a growing garden market with cheap, sound, virus-free bulbs of superior garden lilies which have been thoroughly tested for at least ten years in amateurs’ gardens all over North America.
The boom in amateur polyploid hybridizing is going to produce a lot of junk. Of course, it will; all hybridizing programs do. Progress only comes when we discipline ourselves to plan crosses carefully with specific goals in mind, and then rogue ruthlessly, saving only the top 1070-5070 each year. Some crosses, however promising, won’t produce
anything of value. Then we learn from our mistakes and try a different angle. Amateurs do have some disadvantages, particularly as beginning hybridizers. We soon run out of fresh soil in which to grow lilies, and as we say in the country, “Every mother crow thinks her little ones are the blackest.” That’s where objective testing under
different growing conditions over several years lets the cream rise to the top. There will be some lucky breaks, but most progress will be due to careful planning, keen observation, keeping careful records, learning from failure as well as success, ruthless roguing, having patience, and keeping your eyes on the prize. The human factors
which drive your program are at least as important as your breeding stock.
So what am I doing in polyploid hybridizing other than ranting about it? Mostly trying to sort out what works and what doesn’t work. Low fertility of most triploidsand converted tetraploids (like Tetra ‘Connecticut King’) means that most crosses produce little or no viable seed. You can save more embryos by using embryo culture,
a technique which is easy enough to learn and adaptable to kitchen table conditions.
Unfortunately, it is a lot of hassle with precious few rewards. I use it mostly for the Orienpet crosses where pods and embryos are scarce, and the endosperm is often deficient. I’ve learned to make as many replications and reciprocals of a cross as possible to increase the size of the seedling population. If you don’t have at least 100 seedlings, you still don’t know the full potential of a given cross, especially with
complex hybrids and polyploid.
I’ve attempted colchicine conversion of a dozen good garden-type diploids with very modest success. So far, only ‘Journey’s End’ and ‘Gypsy’ are showing the large stomates (.005 inches) typical of tetraploids. Only time or chromosome counts of pollen mother cells will tell if the sex organs of these are also converted and not just the
surface layer containing the stomates. I use a 50X pocket microscope to screen these conversion attempts and other seedlings as well.
LeVern Freimann mentioned using this instrument in his 1985 N.A.L.S. Yearbook article. It has been very useful, though it could hardly be called definitive in assessing the exact chromosome number of a
lily. Stomate measurements are only one of several clues one can glean from careful garden observation. To be certain of ploidy, a chromosome count should be done.
Root tip tissue is adequate for chromosome counts of seedlings, but pollen mother cells should be tested on plants resulting from attempted colchicine conversions. My first attempted polyploid cross was ‘Jasper’ x ‘Red Velvet’.What a laugh. In retrospect, one could hardly imagine a less likely mating. Both are triploids and quite sterile both in pod and pollen. My beginner’s luck was bad because I didn’t have
a clue about what works and what doesn’t. That’s about the time Bob and Dianna Gibson of Band D Lilies suggested I consult Dick Thomas in British Columbia. Dick became a good friend and has been very helpful to this beginner ever since. Through Dick, Eckart Schmitzer in Germany, Dr. Jaap van Tuyl in Holland, and Ed McRae, the following practical information useful to amateurs has been previously published:
1) diploid x tetraploid produces mostly triploids
2) tetraploid x diploid produces triploids (and some tetras if the diploid produces some unreduced pollen grains which function much like the pollen of tetraploid plants.) ‘Connecticut King’ and ‘Enchantment’ are diploids which have this trait.
3) triploid x tetraploid produces triploids and tetraploids
4) triploid x diploid usually produces nothing, but may produce diploids, triploid, tetraploids, or aneuploids. (If you get a healthy seedling from this kind of cross, bow to the East and have its chromosomes counted for the sake of scientific curiosity.)
5) As previously mentioned, pollen of triploids is usually sterile, though a few exceptions have been claimed.
My more vigorous and promising seedlings are presently being challenged outdoors (unsprayed) by virus, botrytis, fusarium bulb rot, rodents, late frost, summer drought, wind, hail, and the odd mis-lick with the hoe. Most won’t make it, for as Vicki Bowen says of seedlings in general, “much is promised, but little delivered.”
I hope these garden notes will encourage other amateurs to take up the intermittent joy of hybridizing better garden lilies and to include some polyploids in their work as well.