American Rose Annual, 50: 132-136 (1965)
Unique Genes in Hardy Wild Roses
Percy H. Wright
Saskatoon, Saskatchewan, Canada

If the "pool" of genes already incorporated in today's hybrid teas is to be enlarged, most of the enlargement is likely to occur by bringing in genes from various hardy northern species. The desirability of enlargement is quite generally agreed upon, for the hybrid teas, which rose lovers of previous centuries would doubtless regard as miracles of floral perfection, definitely lack certain plant qualities which would widen their adaptability.

The three qualities which they lack most definitely are hardiness (in the north), and resistance to blackspot and mildew. In addition, some varieties fade in the hot sun, lack the ability to make good own-roots and plant vigor in general. The hybrid teas would undoubtedly have a hard time to maintain themselves in a state of nature, not only in the north, but any part of the world.

A species like Rosa rugosa has all the qualities we would like to add to the hybrid teas, and when crossed with the hybrid teas, is everblooming. But, such crosses are handicapped, as Dr. W. Van Fleet noticed back in the second decade of this century, by inheriting also the undesirable features of the species: short, weak flower stems and excessive thorniness.

A new avenue for bringing R. rugosa genes into high-quality roses was opened with the advent of R. kordesii, a fertile tetraploid sport of a sterile R. rugosa-R. wichuraiana hybrid. Hybrids of R. kordesii have already been introduced, but the possibilities for further achievement through them are not too clear at the moment.

Many northern species, like R. rugosa, are diploids. Diploidy, however is not a permanent handicap to incorporation into tetraploids, as experience with teas themselves proves, and more recent experience with polyanthas. It is more difficult to make use of genes in diploid species than of genes in tetraploid species, but the gates are by no means shut.

R. nitida is undoubtedly one of the northern species with interesting genes which have largely been overlooked. The pink of its flowers is not the objectionable mauve-pink of such species as R. blanda and R. macouni, but a clear pink that has a favorable influence on hybrid descendants. I have not used pollen of R. nitida directly on hybrid teas, but my 'Aylsham,' the result of R. nitida pollen on 'Hansa' H. Rg., was an unexpected achievement. The R. nitida genes greatly reduced the purple tones of 'Hansa,' and favorably influenced flower form.

I wish I had a record of the ancestry of my 'Quadroon.' This is a shrub rose with no merit other than its non-fading and its deep color. It is a single, sparse in bloom and weak in constitution but its color is practically immune to sunlight and is a deep, rich, crimson-red. The evidence, so far as I can judge, is that it is a blend of 'Aylsham' and 'Hansa' which has reverted to a single flower. The color is that of a petal of 'Hansa' which has been unfolded from an unopened bud and hence has suffered no light effect at all. The color of 'Hansa,' in combination with a gene for non-fading from R. nitida, would be expected to result in just such a flower color as that of 'Quadroon"

R. nitida has extremely fine, weak flower stems. The combination of the short, weak flower stems of 'Hansa' with the flower stem features of R. nitida is unfavorable. 'Aylsham' would be a much better rose if it merely had flower stems as good as those of the R. blanda hybrid 'Betty Bland.'

My conclusions on R. nitida are: it probably has a valuable gene for suppression of mauve tones and another for non-fading, but its flower-stem weaknesses is a serious one.

One of the first species hybrids I raised was 'Melanie,' the progeny of the pollination of R. rubrifolia by 'Gruss an Teplitz.' This hybrid, which unfortunately was soon lost, inherited wonderful foliage-color from both parents and the combination of the deep petal color of 'Gruss an Teplitz' with what I suspect is a set of genes for suppression of purple tone and for slow fading in R. rubrifolia, was a happy one. In short, it is just possible that the genes I suppose I have found in R. nitida are also present in R. rubrifollia. This is a cross I have prepared to repeat next year. The results were too lucky to let the combination that made up 'Melanie' remain extinct.

Among the seedlings which bloomed for me for the first time in 1963, was a hybrid between 'Aylsham' and 'Hazeldean.' Again, I achieved a flower of good color and non-fading qualities, but only a single and on a weak plant.

The interesting question is, is the non-fading due to the presence of the gene from R. nitida already inferred to have created 'Quadroon,' or is it descended from 'Persian Yellow,' ancestor of 'Hazeldean'? Or, was the one feature inherited from both? Is a gene for non-fading of yellow able to make red unfading too?

Whatever the answer, I suspect 'Persian Yellow' contains an extremely valuable gene for non-fading. Not every descendant of 'Persian Yellow' will inherit it, which is equivalent to saying that 'Persian Yellow' is heterozygous for non-fading. In any case, 'Persian Yellow' pollen should be used by rose breeders far more freely than it is. I am not ready to say that, in our northern climate, a greater percentage of 'Persian Yellow' pollen is fertile than it is farther south, but I am ready to state that, when 'Persian Yellow' pollen is used it is quite easy, in our climate, to get a seed set. It's really too bad the gene for susceptibility to blackspot in 'Persian Yellow' turns up so often and so seriously in the pernetiana group. This group has since been absorbed by the hybrid tea group.

Thornlessness is a valuable feature of any rose not intended to make a "living fence, bull-tight." Where can we get this valuable feature?

R. blanda possesses many clones which are completely thornless, including the St. Hilaire clone which I imported in the late 1930s from St. Hilaire, Quebec. This is a pale-flowered selection which has proved to be almost as hardy in the Prairie Provinces of Canada as our own natives. I have used it chiefly to cross with 'Betty Bland,' Dr. F. L. Skinner's R. blanda-hybrid tea hybrid. The features of the numerous descendants of this ancestry lead me to believe that roses with long strong, erect flower stems are more likely to result from infusions of R. blanda genes than infusions of the genes of any other of our native wild roses. However, R. blanda hybrids seem to be especially susceptible to mildew, which is one important strike against them.

The dwarf species R. suffulta, native to the drier parts of the three Prairie Provinces and south into the plains states, is a most remarkable species and surely has genes which should be noted.

Its flowers are of poor color, pink with mauve tones in some clones, and frequently streaked and extra fast-fading so there is nothing to be gained from R. suffulta in these respects. It does not endure shade, and if this feature were inherited by a hybrid, the handicap could be serious. However, the good points of the species are also definite.

It is dwarf, about ten inches in the smallest forms, ranging to three feet in the tallest. It includes several double flowered strains, of which 'Woodrow' and 'John Allen' are most outstanding. It is remarkably drought resistant, which is doubtlessly due to deep rooting. It will stay alive and continue to grow in prairie fields where the grasses have dried up weeks earlier for the midsummer dry season. And most important of all, it will bloom again in the fall.

This is not equivalent to saying that it is everbloomng, which term should be reserved for the familiar type of repeat blooming in the polyanthas, floribundas and hybrid teas. But, here in its native haunts, it does bloom right up to the killing frosts of mid-September.

Each branch, when it grows to the height at which it intends to stop for the season, blooms. Along the roads and highways of our province, plants which, earlier in the year, have been cut to the ground by road scrapers on the edges of the travelled part, can be seen blooming over miles and miles, throughout August and well into September.

Just what use can be made of this peculiar type of fall blooming is hard to say. I once crossed R. suffulta with 'Hansa,' and found that the hybrids were once-blooming. Each parent had suppressed the type of fall blooming of the other. Each type of fall blooming would probably have reappeard by segregation in later generations, if I had raised any. But these plants were triploids and I do not recall ever seeing a hip. One of the advantages of R. suffulta is that it is already a tetraploid.

Another native North American rose species of rare qualities and attractive possibilities is R. foliolosa, which is also remarkably drought resistant. I have had it for only a few years, so can say little about Its promise. It is hardy to the snow line here in Saskatchewan, which is remarkable for a species of such southerly origin. Its feature of value here is the fact that it does not bloom until after the rose curculio, the chief handicap of our hardy shrub roses, has disappeared for the season. The foliage is unique and attractive.