Difference: InfoHybridizingSpuriasByNiswonger (r6 vs. r5)

Hybridizing Spuria Irises by Dave Niswonger

HYBRIDIZING SPURIA IRISES

As you ponder the idea of hybridizing Spuria irises, remember that in many cases we are only six or seven-maybe eight generations from the original species; whereas, tall bearded hybridization may be as far as twenty five generations away from the species. This is said only to say that we are just beginning to explore the possibility of what may be hiding in the spuria genes we have available to us. Also, there are not many people hybridzing spurias. Only about seventeen persons have registered spurias in the last few years and on any given year, there may be only five. In 2003 there were twenty five cultivars registered.. So, the need is great and the opportunity boundless.

Now if you wanted to work on something different, you would need to find the cultivars that may give a hint of that trait. Siberian iris breeders will say that if they can see the color in the flower, they can bring it out which is how some of the yellow Siberians have been developed. This may or not be true with spurias. You want a pink spuria so you cross two cultivars with hints of pink (an old rose color perhaps). You grow the seedlings and none of them may look like the original parents. You may make another cross with no hint of pink and a rosy hued seedling may show up. If this happens, use it with another like it and keep trying. You may cross two purples and brown shows up. Outcomes are not as predictable as with tall bearded but we haven't gone as many generations either. One of the problems too is that we don't know if we a dealing with diploids (two groups of chromosomes) or tetraploids (four groups). You might want to double the chromosomes of the smaller species (twenty chromosomes) to use with the tall ones (forty chromosomes) which would seem logical but if one is a diploid and the other a tetraploid and you grow seedlings, they may be triploids and probably sterile. But, this doesn't always happen so I wouldn't say don't try it. This is where experience is so important and when this can be shared, it helps everyone. If you cross two yellows, its pretty likely that you will get various shades of yellow and maybe gold or orange (wouldn't that be nice?). Some breeders like Jim Hedgecock, are interested in ‘dark tops' as in tall bearded breeding (or you may wish to call them reverse amoenas) but this is another color pattern of interest if you can get larger sized standards.

Creating hybrids seems to broaden the base of adaptability. Ben Hager used to say that you may make many crosses and not get any seed but if you finally get just one seed and it grows, it is usually fertile and you have new genetic material with which to work.

out of I. halophila and the first of the tall ones to bloom. Other small ones of Jenkins' seem to appear from larger parents such as: ‘Tiny Lou' 1990 from ‘Protege' and ‘Dawn Candle', ‘Little Frills' 1998 from ‘Color Focus' 1990 selfed and ‘Little Splash' 1997, a creamy yellow with a large splash of yellow in the falls but does have I. xanthospuria in the background through ‘Elixir' (Hager 1964), ‘Minitrend' 1997 has ‘Color Focus' in the background which goes back to ‘Ila Crawford' (Hager1976). According to Eric Tankesley-Clarke from Adamgrove, Ben Hager had some small seedlings from ‘Ila Crawford' background. As mentioned, Ben Hager used I. maritima, I. carthalinae, and I. demetrii as well as ‘Protégé' (Hagerâ€^TM69) which is out of I. carthalinae (also, ‘Neophyte' 1964 which has summer green foliage as well). Ben crossed ‘Protege' with I. klattii and got some small ones from that cross too. Its interesting to note that the species mentioned are all from the tall group with I. halophia, I. carthalinae, I. musulmanica and I. klattii all having 44 chromosomes. I. demetrii and I. maritima having 38 chromosomes and I. xanthospuria with 40 chromosomes. Dr. James W. Waddick in an article titled as "The State of Spuria Irises" (AIS Bulletin Vol. LXXXV, No. 3, July 2004 pages 82 to 86) suggests that hybridizers should be using some of the smaller species such as I. graminea (34 chromosomes), I kerneriana ( 18 chromosomes) and I. sintenissii (16 chromosomes--Simonet counted 32 in a tetraploid form of it). This is food for thought. Botanists and taxonomists can not agree as to how many species there are but the writer feels there are about sixteen which gives the hybridizer a great selection from which to choose. Look for seed offered by SIGNA and the British Iris Society.

Oleg Amekhin from the Ukraine has crossed I. haliphila with I. graminea and he says the results were not very good. The stalks were about 40-50 cms (1.5 ft.) and the flowers were a dirty blue. He says these hybrids were 100% sterile which is understandable to some degree when you consider a 44 chromosome species crossed with a 34 chromosome species would give you a 39 chromosome hybrid and the odd number of chromosomes would make it difficult to connect half of them with something else. But, this writer wouldn't say not to try it. Amekhin got earliness in a hybrid from crossing I. klattii with I. sogdiana (This is 44 ch. crossed with ??? , if sogdiana is a subspecies of I. notha it would be 38 ch. which would give a hybrid of 41 which is unlikely but if a subspecies of I. spuria grouped with I. halophila it would be 44 which is more likely). From this cross there was an interesting blue with a nice stalk about 3 feet tall and a light purple with cream colored style arms. The latter, he registered as ‘Gratsiya' in 1996.

The writer has grown I. graminea and I sintenissii but was unable to make any crosses with them. He has tried to grow I. kerneriana from seed several times and did not come up with any plants. Berney Baughen from England has had success growing this yellow with strongly recurved falls. He says I. kerneriana usually has two flowers per stem flowering above narrow green foliage and takes 3 to 4 years to form into neat compact clumps. The roots are shallow and resent disturbance but can be moved if careful to bring enough soil with it . The writer had thought that this might be a good one to double the chromosomes giving 36 chromosomes which when crossed with a 44 ch species a 40 chromosome hybrid could be achieved.

Doubling chromosomes on spurias may be difficult since its harder to control germination of the seed as compared to others. It might be that if the seed could be picked green, just as the seed pod is starting to crack, sterilizing them with a chlorine solution and storing in a refrigerator in a Petri dish between dampened filter paper, that germination would occur in a couple of months or so--then soaking them in a solution of cholchicine, Treflan or Surflan just as the seed start to split (germinate) then rinsing extremely well, doubling might be achieved.

Again working with the smaller species may pay off big but this writer doesn't think it will be easy. He has tried to grow I. pontica several times but has never gotten plants. He has been growing I. machowii for three years and hasn't gotten it to bloom and the same with I. ludwigii (it and I. pontica are good for rock gardens since the bloom is close to the ground and the foliage is its best asset). I. pontica is normally in the blue-purple range of colors, sometimes a rosy violet,but Michael Diev from Moscow and Berney Baughen from England, had yellow forms appear in their seedlings but I think both of growers have lost them now but that's an indication of the possibilities. Its the shortest, along with I. ludwigii, growing 2 inches high but having the most chromosomes of all with 72.

Most beardless irises can be pollinated very easily by insects since the stigmatic lip is so close to the falls. Bumble bees especially, like spurias, and when they go down into the flower for nectar their back is covered with pollen which dusts the stigma. In order to prevent this, pull off the falls just as the flower is about to open and the bee has no landing field.. Generally, the stigmatic lip is not receptive to pollen until the second day from opening. If the weather is hot and dry, you could pollinate the first day and again on the second day. Although most spurias have no fragrance, there will be lots of insects, wasps and bees around spurias. This is because bubbles of nectar form on the outside of the ovary at the base of the flower, its like syrup, just take your finger remove some and you will see its delicious. I. lactea also does this but you will have to cut the flowers and take into the house to see it since the insects keep it clean. Because of this, Dr. Rodionenko thinks I. lactea is close to I. spuria and crosses can be made. Charles Jenkins has tried this and may have some interesting results but the seed he has sent me showed no signs of a hybrid. I. lactea sets seed so easily--its almost as if pollen flying through the air can find the stigmatic lip even though the falls have been removed. The chromosome count is not known so various counts of chromosomes of spurias could be used to see which might work. Dr. Rodionenko thinks I. xiphium would cross with spurias even though it is bulbous. These are Dutch irises. I xiphium has a 34 chromosome count which might work with I. graminea. But many Dutch irises are hybrids between I. xiphium and I. tingitana which has counts of 28 and 42 and also possibly with I. latifolia with a count of 42. So, the hybrids of Dutch irises could range between 28 and 42 but if you had one with a 38 count it might cross with some of the 38 chromosome spurias. There are lots of possiblities in the hybidization of spuria irises.

Now getting back to the pollination, when you have completed the cross, tie a tag on it listing the seed parent first. When the seed pod matures, pick it as the pod starts to crack open. You will find very light in weight seed that the wind could almost blow away. The color of the seed will range from white, ivory, pink to almost black. The writer has found, though not a scientific study, that the lighter colored seed produce like colored flowers and the dark colored seed, darker colors. If you plant the seed immediately, it will germinate before winter and grow about one inch tall in Missouri. If the temperature drops to zero F in your area, you might put on a light mulch but not too heavy as to smother the seedlings. Then remove it in early spring. This will give them a head start and when they reach 3 to 4 inches high you can transplant them. If you grow the seed in a greenhouse, you may have a damping off problem. If this is the case use some Terrachlor in the soil of pot. Spurias are very susceptible to mustard fungus so you may want to put some terrachlor in the row when planting them. A 10% granulated form may be obtained from Union Carbide Co. which indicates iris on the label. This is an easy way to use it in the granulated form. If you plant them before the tall bearded bloom, many will flower the following year. Use a fertilizer in your water preferably one that has a root stimulator in it when you transplant them. In the row sprinkle some 14-14-14 Osmocote or slow release fertilizer and some alfalfa pellets which have a growth stimulant in them. If you don't plant the seed when they are green and they go dormant you would plant them in the fall. They may not germinate the following spring so you would leave them there for another year. Some of them may germinate and you could plant them or wait another year. Growers in the southwest U.S. and California might want to wait until fall to transplant them just when they are transplanting mature plants. They would grow all winter long and bloom the next spring. The writer has had some seed that took four years to germinate. So, plant the seed in a place that you can leave for at least two years. Pots as well as a seed bed can be used to germinate the seeds. Seed will last for several years; therefore, if you don't get them planted, save them for another year. It may take a couple of years for the plants to bloom and even three if you live in the north.

-- Main.RPries - 2010-07-06