American Rose Annual (1985) 82-84.
A Thornless Rose Descended from Rosa carolina
Robert E. Bayse

P O. Box 494, Caldwell, Texas

Editor's Note: Robert Basye is an amateur rose hybridizer who retired as a mathematics professor from Texas A & M University in 1968. He became enamored of the rose 49 years ago and has been a member of the American Rose Society since 1937. Now he spends almost all of his time in his garden and is looking forward to next year, his golden anniversary with roses.

When I first began hybridizing roses some 30 years ago, my prime objective was to make at least a beginning on the age-old problem of blackspot. I had already built up a good collection of the wild roes and had become especially attracted to the healthy foliage of R. bracteata, R. laevigata, R. carolina and several others. After ten years of hybridizing I began to get a faint glimmer of some of the enormous difficulties involved, and my morale began to sag ever so little.

Then serendipity intervened. A thornless rose suddenly appeared in my garden. The story of this rose is the subject of this article.

R. carolina is a tetraploid which crosses easily with many garden roses. One cross which I made in 1956 was R. carolina x Hugh Dickson. Among the open pollinated seedlings of this cross was one which, during its first year of growth, appeared to be thornless. During its second year, however, a few thorns appeared on the laterals. I then grew 15 open-pollinated seedlings of this rose, one of which proved to be completely thornless. It bears the number 65-626, being seedling number 626 of the year 1965. This implies that the bees carried out the actual pollinating in the year 1963.

It would be nice to know whether the two open-pollinations mentioned above were selfs or involved other roses in the garden. We will never know, but the credit must go to the bees. They achieved in two lazy afternoons what I could not likely duplicate in a lifetime with a pollen brush.

Not only is 65-626 completely thornless, but the midribs of the leaves are perfectly smooth, a property posessed also by its mother. The growth is vigorous to six or eight feet. The flowers are single, pink, small and occur in clusters on strong stems, somewhat reminiscent of R. carolina. The foliage has high resistance to blackspot.

My record book shows that in 1961 I made a somatic chromosome count of the mother of 65-625 and found it to be 28. Apparently I never got around to making the count for 65-626. But over the last 20 years, its wide compatibility with garden roses, both as male and female parent, leaves little doubt that it, too, is a tetraploid.

Selfed seedlings of 65-626 are generally thornless with smooth midribs. Rarely a thorn will appear. But roughly half will have a few fine bristles low on the canes, close to the base of the plant. This is clearly a throwback to R. carolina, which has a generous supply of these base bristles. To prevent the frequent reappearance of these latent (recessive?) bristles in later crossings, I would suggest several recessive selflings of 65-526. This was one of my oversights as an amateur.

But even without first abolishing the bristles, 65-626 has made some remarkable crosses. When crossed with a thorny rose, the thorniness is usually much reduced. Occasionally the F1 cross will be completely thornless. For example, I have thornless plants with smooth midribs and no bristles by using as pollen parents, Crimson Glory, Don Juan, Sibelius, and some unnamed hybrids. And similar plants have also come by applying the pollen of 65-626 to My Choice, Soria Horstmann and various unnamed hybrids.

One of the thorniest roses that ever graced my garden is a probable amphidiploid arising in 1967 as a tetraploid seedling of the diploid cross R. abyssinica x R. rugosa, which I made in 1955. In 1975 I applied to this horrendously thorny rose the pollen of 65-626. One of the seedlings, 77-361, was not only thornless and free of bristles but had perfectly smooth midribs! It carries genes of three wild roses and has, like 65-626, easy compatibility with other roses, both as seed and pollen parent.

Recently I grew 36 selfed seedlings of this rose. None had bristles! 29 were thornless with smooth midribs; three were thornless with rough midribs; three had a few thorns and smooth midribs; and one had a thorns and a rough midrib. Also, five of the seedlings showed some recurrence, possessed also by the mother, 77-361. This may be a throwback to the rugosa ancestor, or even to Hugh Dickson.

I consider 77-361 to have high promise for future breeding.

The three roses above described, 65-626, 77-361 and the probable amphidiploid are now growing in the Huntington Botanical Garden. Interested rose breeders having understocks can obtain budsticks in return for any contribution to the Huntington Rose Research Fund. Letters may be addressed to The Curator, Huntington Botanical Garden, 1151 Oxford Road, San Marino, CA 91108.

If 65-626 should, in younger hands, be privileged to play some role in the thornless garden roses of the future, then perhaps it should a name. I have chosen Commander Gillette, for the navigator on the light cruiser, USS Marblehead, on which we both served during World War II

I cannot close without making an embarrassing confession. I have long known that roses which have been thornless in my garden for a number of years may suddenly, for no civilized reason, throw a thorn. Ken Nobbs of New Zealand, in his most interesting article in the 1984 American Rose Annual, mentions such a seedling which grew for seven years before throwing its first thorn. For 20 years I have searched for that first thorn on Commander Gillette, hoping never to find it. But last November, running my hands through one of these bushes, I found it! There's a mystery here. Why? And why must perfection, like truth, be so elusive?