Society for Louisiana Irises
Introduction to Louisiana Irises
In this section, the details of choosing parents, establishing breeding lines, and the basic flower color genetics of LA iris are considered.
Many people are under the misconception that hybridizing requires advanced knowledge of genetics and large amounts of space to grow seedlings. Although these both may be considered assets, some of our most succesful hybridizers, such as Joe Mertzweiller and Charlie Arny, had relatively small areas for seedling growth yet both won the AIS Hybridizer's Medal and produced numerous award-winning irises.
Below are described the steps that I and others have used with success not only in hybridizing LA irises bit other plant groups as well.
1. Pick an objective in your breeding Although it might seem exciting to breed all colors and patterns, one will make more progress if one chooses just a few objectives and concentrates on these. As a begining hybridizer, it might behoove one to pick areas of emphasis that other hybridizers have not chosen. For example, there has been relatively less work done with the doubles, spiders, and short (patio) type flowers of any color.
2. Collect parents for breeding stock Now that you have an objective, it is important to obtain a number of parents that meet that objective. By attending conventions and reading comments in the newletters and bulletins select cultivars that represent the best for the particular goal you have chosen.
3. Choosing parents and doing the crosses Now that you've asembled the potential parents for your breedibg objective, combine the parents that most closely meet your goal. Try not to combine parents with the same faults as it is likely that all the offspring will have these faults as well.
4. Growing on the seedlings The seedlings must be grown in a manner so that you can recognize improvements. A poorly grown seedling is impossible to evaluate, especially for characteristics unrelated to the blossom. Louisiana iris seedlings require abundant moisture and nutrients to perform optimally. Preparation of seedling beds with incorporation of organic matter and fertilizer is a must, especially in situations where the sedlings are crowded. A watering schedule that guarantees an inch of water/ week improves the chances of seedling bloom significantly.
5. Evaluation and further crossing As the seedling crop blooms, you will note both superior and inferior individuals within the crop. Although there may be no individuals worthy of naming (and of course, naming any seedling should not be done until after at least several bloom seasons), recognize any that might be improvements and thus useful for further breeding. My practice is to number the seedling and record any information on the charsacteristics (color, form, size, branching, etc.) of the seedling in a notebook.
The two basic methods of plant breeding are out-crossing and line breeding. Outcrossing brings together different sets of genes and, when the breeder is lucky, the right combinations give superior offspring. Line breeding allows intensification of particular traits without diluting the traits of interest by crossing to unrelated individuals. One potential problem with line breeding is that deleterious recessives may also be gathered, leading to a loss of vigor.
6. Specific color and type recommendations Each of the colors and patterns in LA iris blooms has areas of strength and possible areas for improvement. Whites- Whites are one of the most advanced color class, with outstanding examples of form, substance and vigor. Areas of possible improvement include the production of whites with contrasting styles, laciniation, and deeper veining (such as in Cotton Blossom).
Yellows- Many yellows have excellent form and substance but color fastness is a problem, especially in the deeper shades, towards bright gold and orange. Muddiness, with anthocyanin coloring overlaying the yellow is also a problem in some of the deeper shades, although when the effect is even, as in Praline Festival, pleasing caramel to brown tones are produced.
Blues- Blues in LA iris come from two sources, larger ones derived from giganticaerulea that are generally more towards lavender-blue, and smaller generally of a brighter hue derived from brevicaulis. Purples- Mary Dunn has developed the blue-purple class to its present state by adding form and size to this class that were previously unobtainable. Pinks- No pinks similar to the lycopene-containing pinks of bearded iris are found in the LA iris but a pink effect is obtained by light lavender-blues, orchids, and roses from diluting out dark lavenders, purples and reds, respectively. Advancements towards purer pinks are coming and cultivatrs with good form and substance in each of the approaches to pink may be had.
Amoenas and variegatas- Although amoenas are relatively rare in the LAs, preliminary results indicate that at least some of this type are dominant to elf-colored blossoms.
Flower Color Genetics of Louisiana Iris
An elementary presentation of basic flower color genetics should be helpful to hybridizers in planning crosses for a given flower color. Some of the results from specific color types is presented in the various color classes. Readers should refer to the chapters prepared by Ken Kidd in The World of Irises For a more deetailed description of genetic principles.
Two major types of pigments of pigments are responsible for the colors in LA iris blossoms, carotenoid pigments that give the yellow colorations to the blosssom, and anthocyanin pigments that give the blue, purple and red colors to LA iris.
© 2000 SLI All rights reserved.
© 2000 SLI All rights reserved.