The Garden Magazine, 19(6): 332-334 (July, 1914)

The Making of the Red Sunflower
Wilmatte P. Cockerell, Colorado

AN ACTUAL RECITAL OF THE FIRST DISCOVERY OF A RED COLOR IN THE SUNFLOWER,
AND HOW IT WAS FIXED AND BROUGHT INTO PRACTICAL USE

(Editors' Note: This is a personal account of an actual achievement in plant breeding by an amateur gardener, and is an excellent illustration of a field of vast possibilites that lie open to all. But very little has yet been done in actual plant breeding in American gardens; yet it is a field of endeavor that should prove most attractive. Gregor Mendel's work illustrates forcibly the value of exact methods and careful records. He probably did not realize at all what he was doing when he experimented with his garden peas. Yet he discovered a set of laws that we, a generation later, are using to great practical advantage. Breeding is now almost an exact science, thanks to the work of the obscure monk in his little monastery garden.


(See colored illustration on this month's cover)

THE "Insects' Homer" begins one of his inimitable essays by inquiring "Do you know the Halicti? Even if you do not know the Halicti you may still enjoy some of the minor satisfactions of life." I should inquire if you had ever tried making plant hybrids, and if you had not I should insist that you had missed one of the great satisfactions of life, one of the most interesting reasons for associating with plants.

We had been long interested in breeding experiments, the Master of the Garden and I. We had visited Bateson's gardens at Cambridge, England, seen Standfuss's wonderful moth hybrids at Zurich, Switzerland, studied Morgan's curious little flies, and listened to Davenport's explanations of his wonderful experiments at Cold Spring Harbor, and all this work seemed to show that a new era was beginning for the practical breeder. It seemed to us that it would be difficult to overestimate the importance of the results to be obtained during the next fifty years, and we often sighed for some little thing that we might have of our own, in our own back garden. We were agreed in wishing to work with plants, but we had no thought that we should have the great good fortune to perfect a plant that would be grown in many gardens in distant parts of the world. Our experience is not unique, but it is rare enough to seem worth the telling.

But to the story: Having occasion to cross the road near our house one warm August morning I saw what I took to be a large red butterfly on the head of a sunflower growing by the roadside. Glancing at the plant a little later, I was surprised to see that the butterfly had not moved, and when I approached nearer I saw to my astonishment that there was no butterfly but a sunflower with rays deeply suffused with a satiny, chestnut-red. There was only one plant with red blossoms, and this close to the road where hundreds of people passed daily, and already one of the heads had been carried away as a curiosity. That evening I took the Master of the Garden to see my find.

We were agreed that we could not leave the plant where it was; it would almost surely be destroyed. We had no experience in transplanting full grown plants, so we studied the root system of a common sunflower, carefully lifted our red treasure, planted it in the garden, shaded it for a day or two, and it seemed hardly to feel the shock, but went on blooming normally.

The next thing was to find out just what work had been done in crossing sunflowers, and we found on looking up the literature, that sunflowers are self sterile. Here was a dilemma; there was, so far as we knew, and we had seen millions of sunflowers, only one plant of the red sunflower in the world, and this alas, could not be self fertilized!

The only thing to do was to make crosses with the ordinary sunflowers and see what would come of it. And here was the supreme interest, for we could to some extent, predict the result of these crosses since we had a key to the age-long riddle of heredity. The man who furnished this key was Johann Gregor Mendel, an Augustinian monk, Abbot of the old Monastery of Brunn, who by a careful study of garden peas through eight years, discovered laws and ratios which seem little short of magic. He had discovered a nature-secret of untold value not alone to plant breeders but to the human species in its upward evolution. But he was ahead of his time, and Darwin, the one man in the world who would have seen the importance of this work, never heard of the experiments of the nature-studying monk at Brunn and so this wonderful thesis lay forgotten for more than thirty years. In 1900 three European workers almost simultaneously discovered Mendel's paper and to-day "Mendelism" is talked of everywhere.

The result of crossing Helianthus cucumerifolius and H. culicularis (red). The base of each ray is splashed red

Now to return to the sunflower. The first thing we were anxious to know was whether the red would be dominant or recessive; that is, would it show in the plants coming from our crosses or would it be hidden or covered by the yellow. During the following summer we went East, but before we left, we noted that some of the young plants showed a great deal of purple in the stems. On our return early in August, a gorgeous sight met our eyes, for the sunflowers were in full bloom, and about half were splendidly red. How could we reconcile this with Mendel's law? All were crossed with red and if red were dominant then all should be red; if it were recessive, all should be yellow.

The explanation is that the original plant was a half-red, though it may have had no red parent. In many similar cases plants and animals have been understood only after being used in breeding experiments. The Herr Professor wrote it all down in terms of Mendelism, and the diligent should read therein of pure types, of gametes, of zygotes, of the possibility of having heterozygous and homozygous forms. All of which can be understood by the wise and guessed at by others.

But the practical working of Mendelism is the theme of this paper so we return to the garden. All the red sunflowers in 1911, then, were half-reds just like the plant found by the roadside in 1910, but there was this great advantage: we now had a number of plants, and could cross reds with reds. The result was quite as expected, and it was a great day in the garden when the small, dark blossom appeared. The published chart of the year before was now shown in triumph. There was the expected proportion of one yellow to three reds, though most of the intensely red types were bi-colored with the ends of the rays yellow. This was due to the fact that the wild plant carries a factor for marking as well as for color.

Of course, a new plant with surprising and interesting characters is not often found, but it is certainly true that many more good variations would be discovered if people were everywhere on the lookout for them. Aside, however, from the discovery of new things, there is an almost unlimited field for crossing varieties and species, and their recombination along Mendelian lines. The Yearbook of the Department of Agriculture, 1911, makes a generous offer of the services of the government in securing desirable stock for the plant breeder, and the world is being literally ransacked for seeds of promising species, and every one who has a garden or an orchard is asked to aid in the important work of creating new forms or improving old ones. It seems hard to believe that the Yearbook only states a scientific fact when it says that the greatest numbers of new and valuable forms are produced, not in the great nurseries of the world, but in smaller places where the worker can be near the plants and know their individual characters in a way quite impossible to the wholesale experimenter. Then, through Mendel's laws of inheritance, we have learned that half a dozen plants carefully watched and guarded are worth more than forty acres left to the bees' and butterflies' careful but indiscriminate mixing.

HOW WE MADE THE PINK SUNFLOWER

Our first red sunflower was found by the roadside growing among hundreds of yellow ones and though we transplanted it to our garden and spent three years getting the pure bred type, still we were obliged to confess that we had nothing to do with making the first red sunflower. My students inquired skeptically: "Why should the only red sunflower in the world grow near your house?" And my answer that it was sent to reward me for teaching biology to so many young people was never quite accepted. Surely, we were holding something back! There was an ace up our sleeves somewhere and we could tell how it was done if we only would. A good neighbor who had helped us in various ways came one morning begging me to show her just what it was that I put on the sunflowers to turn them into that splendid satiny red! So when we really did make a new color we felt very pleased for here was something that, in a certain sense, at least, we had made ourselves, and we like to tell how it was done, for we have found the making of new varieties of sunflowers most fascinating.

The sunflower head is made up of many small flowers. The outside rays are merely for show while the inside tubular florets produce the seeds. The florets blossom from the outside and about one tenth are ready for pollen at one time. One of the first things we learned about the sunflower was that it was not fertile to its own pollen. I have never got over the wonder of that. Why those tiny yellow grains, all looking exactly alike, should have some property making a union with the ovules of the same plant impossible is one of the mysteries of mysteries.

The practical value of this fact is at once apparent, for one could hardly take stamens from the bud of so small a floret; and though, when there was but one sunflower plant bearing red flowers in the world, so far as we knew, we regretted that it was not fertile to its own pollen, it was this fact that made our later experiments possible.

The first red sunflower was chestnut-red, the red pigment was added to the deep yellow of the ordinary sunflower, and was changed in appearance — just how much we could not tell. We figured out that if we could get the red on a white background we would have a new and lovelier color. Then began a search for a white sunflower, up and down, through field after field, and page after page of seed catalogues. The best we could do was a pale primrose, advertised by Sutton of Reading, England, and called Primrose Perfection. This plant, which comes quite true from seed, has a very dark disk and pale primrose yellow rays; it is a tall upright form usually bearing only one flower-head.

It was certainly interesting to think that we could obtain an entirely new color, due to the redistribution of previously known factors, and predict in advance just what would happen. Like gravitation heredity obeys certain laws, and is a mighty force which can be subjugated and made to do wonderful work both by the plant and animal breed.

Some of the old-time breeders were aware that hybrids could be split up into pure types, though it was generally believed and taught that every living thing had 1/2 of its inheritance from its parents, 1/4 from its grandparents, 1/16 from its great grandparents, etc. Gregor Mendel may well be called the Newton of heredity, for given certain characters of two parents it is possible by Mendel's laws to state how the offspring will inherit those characteristics.

In the summer of 1912 we accordingly crossed the reds with Primrose Perfection, and obtained a quantity of seed. The Pale Fellow was used as the seed plant, the heads were tied up in bags before any of the florets blossomed, and the pollen was taken from a plant pure bred, or homozygous, for red.

All sorts and conditions of red sunflowers, showing the range of variation in the color distribution

A grain of sunflower pollen is a minute spiked ball and a hundred will stick on the point of a pin, but each carries uncounted determiners. That particular pollen carried, among many others, the determiners for red and orange, dominant unit characters, so that the first generation were all practically like the red which furnished the pollen.

We knew that this would be true, for many experiments have been made recently both with plants and animals confirming Mendel's statement that in the first generation all the offspring will be alike, and will usually resemble one or the other parent. That is, when a pure black and a pure white rabbit are crossed, the young will not be partly black and partly white, but entirely black. These black rabbits, however, carry the determiner for white, and if bred together, the next generation, F2, will consist of 1/4 pure white rabbits (like one grandparent), 1/4 pure black rabbits (like the other grandparent), and 1/2 mixed black and white, or heterozygous, rabbits.

Mendel's greatest contribution to the science of heredity, as has already been pointed out, was in showing that in the second generation, technically known as F2, the characters segregate.

In this work with the sunflower we were working with two characters so that the desired colors would appear in three out of sixteen and only one of these would be pure bred or homozygous. The seeds from the greenhouse were planted in the garden and watched with the greatest interest.

According to Mendel's laws, this seed from the greenhouse, the F2 from the primrose and chestnut-red, would give in every 16, beside the 3 showing red in primrose, 9 chestnut-reds, 3 yellows, and 1 primrose.

A type named Sunrise, in which the rays are washed with red

It was these first, of course, that we were anxious to see, and when in July an F2 plant blossomed bearing lovely rose colored flower heads, we almost felt that we were present at creation! Later the colors came according to expectation, and visitors to the garden found it hard to believe that the plants with common yellow blossoms were from seeds from the very same flowerhead as those that produced the plants bearing the bright pink or old rose blossoms. There was nothing new; the red which had been dulled by appearing on top cf dark yellow showed its real beauty on the light primrose background.

A census of the F2 generation showed, cf the plants in blossom, 71 were chestnut-red, the expectation was 69; 19 were yellow, the expectation was 23; 25 were wine colored, the expectation was 23; 8 primrose and the expectation was 8.

The light yellow Primrose Perfection and the dark red form, crossed to give wine colored flowers

Other interesting crosses have been made, and there are many others that can be made for all varieties, and apparently all the species of annual sunflowers can be crossed. One very good hybrid was a cross between the so-called cucumber-leaved sunflower and our red sunflower.

Among other things I have worked to secure long curled rays and small disks and this has been no slight task. One day a workman left his task of road grading to say: "Your sunflowers are mixed with the wild sorts — that's what ails them!" An old farmer from Kansas, when shown the new pink variety, scratched his head doubtfully, "I shouldn't dare have those in my garden, for if one got loose in some man's farm he'd sure think he was off his head."

Many people ask if I think the red sunflowers will be better for chicken feed, which of course moves me to wrath!

I always use my finger in carrying the pollen to the pistils, though some hybridizers recommend soft brushes and others pin scalpels. Every other day for a week we rubbed pollen on the pistils that were destined to make seeds.

We were very fortunate in having an annual for our first experiment, but in spite of that I am always too impatient to wait for all the frost to be out of the ground, but start some of my most interesting seedlings in the house or have them started for me in the greenhouse. By the middle of May the ground outside is ready and our seed bed, with the rows marked by small white markers with numbers in drawing ink, looks like a pygmy's graveyard. We water the seeds every day, for that is the secret of gardening in Colorado and we lost many precious seeds before we learned it. In about three weeks the little seedlings are ready to transplant and though not quite so hardy as cabbages they stand transplanting very well, indeed. We watch the skies anxiously for a rainy day, and when it does not come the seedlings are covered with cans during the day or planted in the late afternoon.

The paper bags put on to protect the flowers from the bees and butterflies serve also to protect the seeds from the birds, for when the seeds begin to ripen finches come in flocks to eat them.

Be sure to have the soil just right, for the finest plants will often show real beauty only when given the best possible conditions for growth.


Popular Science, pp. 373-382 (Apr 1912)
The Red Sunflower
Prof. T. D. A. Cockerell