Experiences with Line Breeding
David F. Hall

PLATE VII. May Hall. A flamingo-pink with delicate ruffling of the margins. Introduced by David Hall in 1954. GIven an Award of Merit in 1956.
Color Photo Courtesy of Cooley's Iris Gardens

Line breeding takes time and patience, but it is more likely to produce desirable results, in my opinion, than by using unrelated or distantly related parents for breeding stock.

Many years ago I tried to produce a good pink iris. All so-called pink iris of that day were orchid- or lavender-pink. For this purpose I selected what I considered the best available parents for this objective: Morocco Rose, W. R. Dykes, Rameses, Dauntless, and Dolly Madison. I then selected what I considered the best of each year's crop of seedlings for further breeding. Color alone is of little value if not associated with such other important characteristics as a good strong well-branched stem, flowers of good size, form and substance; also plant vigor. All of these characteristics should be weighed and given careful consideration when selecting seedlings for further breeding.

By continuing this selection process and staying within the strain, the per cent of genes carrying undesirable characteristics is gradually reduced and the per cent of genes carrying desirable characteristics is increased.

The product of the few outcrosses I have made have been uniformly disappointing. Following years of line breeding from these five named varieties there appeared in 1942, four pink seedlings. I have line bred these four pinks and their offspring without any outcrosses up to the present day with very satisfactory results. They have become known as Hall's Flamingo-Pinks. From this same flamingo pink strain have been derived strains of other colors: golden-apricots, rose, yellows, pale blues, and whites, all with tangerine beards.

The fact that thirty-nine varieties of the flamingo-pink strain have been named and introduced in commerce, and that twenty-seven of them have received one or more awards from the American Iris Society is evidence that controlled line breeding has produced gratifying results. Many other hybridizers have used numbered and named varieties of this strain in their breeding programs with good results.

For a time I feared this strain, due to long years of line breeding would lose some of its vitality, but to my surprise, by careful selection and without any outcrosses, it has gradually increased in size and vigor as illustrated by the variety May Hall (Plate VII). This may be due largely to attention given to vigor when making selections for breeding.

Year after year there has been a noticeable increase in the quality of seedlings from this strain of iris, and to-day's seedlings are vastly superior in every respect to those of a few years ago.

Yes, by careful selection and line breeding, I believe the goal of the iris breeder is more likely to be reached than by other methods.