ACCOMPLISHING THE APPARENTLY IMPOSSIBLE WITH THE AMARYLLIS
WONDERFUL NEW BLOSSOMS NEARLY A FOOT IN WIDTH
I take it that a flower ten to twelve inches across occupies about the relative position among flowers that a man ten to twelve feet high would occupy among men. Doubtless you have never seen a ten-foot giant, for I believe there is no record of any human being of that size. And I presume that you have never seen a ten-inch flower, unless one of my giant amaryllis blossoms has come to your attention. At all events, it is rare indeed that any flower here in the temperate zone attains even approximately such a size. The blossoms of some of my new artichokes spread out to the same dimensions as Lilium auratum, and exceptionally there may be an individual blossom of some other species that has a spread that approaches the same mark. In general, however, as everyone knows, flowers are accounted large if they exceed six inches in diameter, somewhat as a man is accounted large if he exceeds six feet in height. But several of my new giant amaryllis, with their ten-inch spread of petals, are very anomalous and extraordinary flowers. As I said before, they occupy among flowers a position not very different from that which would be occupied among men by a ten-foot giant. If no ten-foot giant has ever appeared, it is probably not so much because the human race does not have potentialities of producing such a specimen, but that experiments in selective breeding of men for the quality of size, comparable to the hybridizations that produced the giant amaryllis, have never been carried out during a series of generations.
Everyone has heard of the attempt that was once made by a Prussian king to develop a race of giants by selective breeding. As the story goes, the king marshaled all the tall men he could find into a special regiment, and sent inspectors over his kingdom in search of tall women as wives for his tall soldiers. He intended thus to produce a royal bodyguard of giants that should be the astonishment of the world. And no one who has followed out a series of experiments in selective breeding of plants, and who realizes the essential identity of the principles of heredity, applied to men and plants alike, will doubt that the would-be developer of a race of giants was on the right track. He was starting out in just the way that I started when aiming to produce a race of amaryllis plants that would grow gigantic flowers. But even had the royal experiment in man-breeding been carried forward by the successors of the originator of the idea, it would have been a long time before a giant appeared among the royal guards that overtopped his fellows in such proportion as the giant amaryllis outspreads its companions. For there is a time element in these breeding experiments that cannot be ignored; and the units of measurement are not years but generations. In the case of the amaryllis a generation varies somewhat with different species and varieties, but frequently is not more than two years. In other words, many species of amaryllis will produce seed in their second year, when grown from seed. And at most three or four years suffice to bridge the gap between successive generations. But a human generation spans a gap of something like a quarter of a century. As a rule the most vigorous and healthy offspring are not born until their parents are at least twenty-five years old. So in making an analogy between the breeding of a giant amaryllis and the breeding of a giant man, it is necessary to bear in mind that ten generations of the amaryllis are compassed in the span of a single human generation. In other words, the plant developer may logically hope to produce with his amaryllis, in a period of twenty-five years, a development comparable to that which the royal breeder of giants could hope to have duplicated only in the reign of some successor, perhaps of another dynasty, 250 years later. It has taken at least ten generations of hybridizing and selection to produce my giant amaryllis. So we may assume that if the project of the Prussian king, which was inaugurated about the middle of the eighteenth century, had been systematically followed up by his successors, there might be a possibility that a ten-foot giant would have appeared among the descendants of the giant guardsmen about the year 2,000 A. D. We may add, however, that it would probably have been necessary to extend the search for giants, to breed into the strain of royal guardsmen, far beyond the bounds of Prussia. Reasoning still from plant analogies, we may assume that the full measure of possible development in the direction of the ten-foot giant would have been attained only when men and women of widely divergent races-Turks, Persians, Hindoos, Negroes, Patagonians, South Sea Islanders-were brought into the coalition and mingled with the European races. And in making this illustration I am only seeking another way of emphasizing the truth which we have seen illustrated in many fields, that the widest possible range of variation, and therefore the greatest possible opportunity for development along any given line, can be stimulated only by the hybridization of species or varieties that are divergent almost to the limits of affinity-using the word affinity in the sense defined in our earlier studies of cross-fertilization. It was thus that my gigantic walnut trees were produced, as the reader will recall. It was thus that the fruit of the little beach-plum was magnified from the size of a berry to that of a nectarine. It was thus that the giant among small fruits, the Phenomenal berry, was brought into being. And such also was the origin of the giant spineless cactus plants, and of numerous other plant developments in their way quite as remarkable, even if not always so spectacular.
FLOWERS VERSUS MEN
With the breeding of a giant race of men, we are of course as little concerned as the successors of the Prussian king who inaugurated the short-lived experiment. There is no real demand for a race of human giants. They would not fit into the scheme of things. Houses and carriages and furniture are not built for them. At best they would be but curiosities, and the world produces quite enough human curiosities by accidental breeding without starting out systematically to secure them. But it is quite otherwise with plants. Here the production of curiosities-that is to say, plants that differ conspicuously from their fellows of the same species-is an object considered quite worth while, because these plant curiosities, provided the anomaly they present has to do with some in-offensive quality, give pleasure and profit to plant lovers everywhere, and add to the sum total of human happiness. Such a product as the giant amaryllis, for example, excites universal admiration. The mammoth flower is a thing of genuine beauty, regardless of size; and if mere size does not in itself accentuate the beauty, it at least does not detract from it, and it brings to the beholder an added sense of wonderment that enhances the satisfaction with which the flower is viewed, and gives a pleasurable stimulus to the imagination. So it may be assumed that the task of developing this unusual flower was a task quite worth the doing. It called for many years of earnest effort, of patient waiting, and of intelligent selection. But the results fully justify the effort. The story of the difficulties encountered in the early day of my experiments with the amaryllis in effecting cross-fertilization of the flower has been told in an earlier chapter. The reader will recall that I was at first unaware that the pistil of the flower matures at a later date than the stamens; hence that for a time I applied pollen carefully to the pistil of flower after flower before it had attained the receptive stage, and so failed to get any results. But in due course I learned that the pollen must be taken to the pistil of a flower that has shed its own pollen several days earlier and when I understood this simple feature of the technique of cross-fertilizing the amaryllis, I had no further difficulty as to that part of the experiment.
MATERIALS FOR THE EXPERIMENT
The material with which I began my experiments consisted of a few familiar species of the genus Hippeastrum. Properly speaking, this genus should not be called amaryllis, as that name belongs to an allied genus with which we shall make acquaintance presently. But the various species of Hippeastrum are known universally as amaryllis to the florist, and it will be convenient here to follow the general custom of applying that name to all the members of allied genera that are grouped together horticulturally and everywhere referred to as if they were of one tribe. We shall see presently that the members of the different genera, including not only the hippeastrums and the genus Amaryllis itself, but also Sprekelia, Crinum, and Brunsvigia, have been variously hybridized in the course of my experiments. Thus the affinity suggested by their similarity of appearance is demonstrated, justifying at least in a measure the convenient horticultural custom of applying the familiar name amaryllis to all of them. Peculiar interest and probably exceptional importance attaches to the fact that the first group of plants of this tribe with which I experimented included the forms of cultivated amaryllis known as Hippeastrum Johnsoni, H. vittatum, and H. reginae. The significance of this lies in the fact that although these are plants of quite different characteristics, so that they everywhere rank as good species or fixed varieties, yet in point of fact the one first named, Johnson's amaryllis, is a hybrid that resulted from the union of the other two species. The hybridizing experiment through which this new form was produced was made as long ago as the year 1799 by an English amateur gardener named Johnson, whose business of watchmaking had presumably given him facility in the performance of such a manipulation as is involved in the hand pollenizing of flowers. The hybrid form thus produced not only took its place as a recognized horticultural variety, but was botanically recognized as entitled to a distinctive name. It has maintained its place alongside the parent forms during the century and more since it was first developed. Doubtless there have been some modifications in the original characteristics of the hybrid through selection, but, for anything we know to the contrary, Johnson's amaryllis retains to this day the essential characteristics of the hybrid developed by the watchmaker through the union of the two other species. Inasmuch as the amaryllis is often grown from seed, it may be assumed that any given specimen of Johnson's amaryllis in existence today, including of course those with which I first experimented, is a generation or more removed from the original hybrid. Not so many generations as might at first thought appear, for the usual method of propagation of the amaryllis is by bulbs. But now and again new plants would be raised from the seed, and it would be natural that the florist should select for seedlings the best and most typical representatives of the species. So we may assume that the specimens with which I worked represented a fixed type of hybrid inbred for a number of generations, yet still carrying the new combination of hereditary factors originally brought together through hybridization of the other forms, already named as H. vittatum and H. reginae.
VERY MIXED PEDIGREES
So when I began hybridizing experiments, and crossed the H. Johnsoni with H. vittatum, I was in reality making a union of a hybrid with one of its parents. The closeness of affinity of the two would insure ready fertilization. But, on the other hand, the balance of hereditary factors that had been attained in the hybrid would be disturbed and the immediate offspring would really represent second-generation hybrids, of which one parent was at the same time a grandparent. The disturbing influence of this hybridization was manifest enough from the outset, and the tendency to variation thus initiated was accentuated in the next generation, which brought into the cross another species known as H. aulicum. It was still further accentuated in the next generation, when I used as hybridizing agent H. Reginea, which, it will be recalled, was one of the original parents of H. Johnsoni. Thus, having started with a hybrid, I had produced three additional generations of hybrids, in which the parent forms were used and a different species added, so that my fourth-generation hybrids had the strains of three species curiously blended. Persons who care for matters of genealogy might find it of interest to attempt to unravel the pedigrees of these fourth-generation hybrids which had for one parent the species H. reginae and for the other a hybrid whose parents were born of a union of H. aulicum and a hybrid of H. Johnsoni and H. vittatum; recalling that H. Johnsoni itself is the offspring of the progenitors of H. reginae and H. vittatum. The questions of cousinship involved in such a union are much too complex to interest anyone but the antiquarian. At all events they need not be untangled by the plant developer. For him it suffices to recall the names and characteristics of the various species and to concern himself with such selections among their offspring as will produce races blending these characteristics in new and desirable combinations. But, indeed, the experiment became even more complex as it proceeded to additional stages. For by this time I was in possession of several other species of amaryllis, and these also were worked into the combination by hybridizing with different members of the fourth-generation hybrids already introduced. The new species would be crossed with various of the hybrids to accentuate certain qualities of size of flower or color or prolific bearing; and the new hybrids thus produced would in turn be interbred, until the tangled web of their heredity was quite beyond unravelling.
But at each stage of such a series of experiments the plant developer of course watches for results and is guided by results. He has learned by this time of the tendencies to variation that exist. He has gained a clear idea as to the various new races that he hopes to develop. And he is able, through selection of plants for his new matings, and through selection among the seedlings of the ones from which to save seeds, to direct the currents of heredity into desired channels. As I have elsewhere phrased it, the plant experimenter becomes an effective part of the environment. He becomes the most important agent in that process of selective breeding through which the evolution of new forms of plant life is brought about. In the present instance, the tendency to variation that was manifested from the outset, was accentuated generation after generation until, after about twelve years of work, I had a colony of mixed hybrids showing wide departures from any of the ancestral forms. Some of the new forms had very large bulbs, and grew plants of exceptional strength, bearing blossoms of unusual size. I had, of course, selected for strong stalks, broad leaves, and abundant bearing and for rapid production of bulbs and ready growth, as well as for large flowers with wide petals of brilliant colors. The original species had usually borne small bulbs, and put out only two or three offset bulbs in a season. The bulbs of the new hybrids sometimes weigh more than six pounds. The stalks that grow from them are of correspondingly increasing size and strength. And instead of putting out three or four new bulbs in a season, these hybrids sometimes multiply so rapidly as to produce a bulb every month, and in the case of some forms a new bulb every week. That is to say, the most prolific species will produce fifty new bulbs in a year, instead of the three or four of the original species. In point of prolific bearing, there is a corresponding contrast. The original species had seldom more than two or three stalks to a bulb, with four or five flowers in a cluster. The new varieties often produce four or five stalks to a bulb, where they have remained in the ground for a few seasons, with as many as twelve flowers to the stem. The enhanced fecundity of the new forms is supplemented by their tendency to early bearing. They will sometimes bloom the second year from the seed, and on the average they bloom in three or four years. The old forms sometimes require six or eight years to come to maturity. As Prof. De Vries has said, I have pretty nearly cut in half the time from seed to blossom in the amaryllis. But of course the most conspicuous contrast of all is in the flowers themselves. In the original species, the largest flowers seldom attain a diameter of more than five or six inches. The new giant species, as already stated, often produce flowers that are ten inches or even more in diameter. There is considerable variation even in the same race, dependent in part on the size of the bulb from which the individual stalks grow. This should always be understood by persons who grow the amaryllis. A bulb that has been ill-treated in its first year, and has not attained large size, will not produce a large flower, even though it have the hereditary factors for large blooming. To produce the largest flowers, we must give the plant a full supply of nourishment, and thus develop a large bulb. The gigantic flowers appear only on stalks that grow from gigantic bulbs. But of course no conditions of nourishment and no amount of forcing can produce bulbs or flowers of gigantic size unless the hereditary strains have been properly blended. And this blending, as I have just pointed out, involved years of experiment, and the bringing together of the traits of many different species. I had experimented with the amaryllis for about fourteen years before I obtained varieties that seemed worthy of introduction. And the new giant varieties are the product of many additional years of experimentation. The variety introduced under the name Profusion several years ago was at that time the most abundant bloomer known. Its blossoms were also relatively large, and it had many points to commend it. But the races that have been developed more recently, through the further blending of hereditary strains, excel this markedly in every regard. Indeed, the newest acquisition to the ranks of the Giant amaryllis have advanced surprisingly upon their recent forebears. And when the gigantic ten-inch trumpet of the new variety is put beside even the largest flowers of the remote ancestral type, the contrast is so striking as to seem to suggest things of a quite different order.
STILL WIDER HYBRIDIZATIONS
Having reached something like the limits of variation attainable through hybridization of the different species of Hippeastrum, I extended the experiments by crossing the new amaryllis hybrids with plants of other allied genera, notably with Sprekelia and Crinum. The Sprekelia is represented by a single species indigenous to Mexico and sometimes called the Jacobean lily. It has long, slender, strap-shaped leaves, and a showy crimson flower of an unusual form that suggests a bird in flight. I have worked on the Sprekelia more or less for twenty years, raising probably a hundred thousand seedlings. But I succeeded only once in hybridizing the plant, with the production of fertile offspring. The hybrid amaryllis that made union with the Jacobean lily was my new vittatum type, having pale red flowers striped with white. Only a single hybrid of this union bloomed, but from this a number of seedlings were grown. The hybrid offspring of these plants of different genera had long, narrow, strap-shaped leaves much like those of Sprekelia (the pollen parent), but the blossoms were very much larger than those of that plant, and they had very curiously twisted petals, unlike those of either parent. As might be expected in the offspring of plants so widely separated, the hybrids were almost infertile. As already noted, only a single variety bore blossoms, and although the blossoms were produced almost continuously throughout the summer, there was seldom any seed, and it was with difficulty that I succeeded in raising seven or eight seedlings. In a more recent year, however, I succeeded in hybridizing many blossoms of Sprekelia with the pollen of an improved hybrid Hippeastrum, and secured about 800 seedlings which showed the characteristics of the other hybrids obtained by the reciprocal cross of the same species. The second generation hybrids, and also those of the third generation, showed a strong tendency to revert back to the giant hybrid species of amaryllis, rather than toward natural species. The bulbous plants of the genus Crinum appear to be somewhat closely related to the Hippeastrums. There are two species known as Crinum moorei and C. iongiflora that grow in Northern California, and there are numerous other species, some of which are evergreens. I have grown about twenty species, some of them of tropical origin. Numerous crosses were made among these species until I had a crossbred strain of Crinums of ancestry as complex as that of my Hippeastrums. The seed parent of a larger proportion of the hybrids was the species known as Crinum Americanum, but a few were grown from the seed of C. Anabilis and C. Asiatica. In the various crosses, the traits of the species of temperate zones appeared to be prepotent or dominant. Interesting hybrids were produced by crossing the Crinums, not with the members of the Hippeastrum colony (this proving impossible), but with the form of true amaryllis known as Amaryllis belladona. The hybrids thus produced were a very curious lot. They seemed undecided whether to take on the flat, strap-shaped leaves of the amaryllis or the tunicate leaves of the other parent. The compromise led to the production of a leaf with a long curious neck. The flowers, like the plants themselves, may be described as a balanced combination of the qualities of the two parents. They are smaller than the flowers of the amaryllis, and more tubular, and in color they vary from the white of the male parent to the deepest rosy crimson, light pink being the most common color. The flowers of the amaryllis vary from rosy pink to crimson. Although the hybrids bloom somewhat abundantly, they never produce a seed. The hybrid plants may of course be propagated indefinitely from the bulbs, constituting thus a permanent variety. But they evidence the wide gap between their parents in that they are sterile.
A LOOK AHEAD
It will be obvious from all this that the colony of amaryllis plants, with its hybrids of intricate lineage, involving not only many species, but four genera, is a collection of plants of altogether exceptional interest. From a mere horticultural standpoint, it is considered by experts to be the best collection of amaryllis in the world. Not only has this colony the greatest diversity of forms but the most extraordinary individual plants. Experts of both Europe and America who have visited my grounds are agreed in pronouncing my galaxies of amaryllis far superior to any to be seen elsewhere, not only in size but in rapid multiplication and general effectiveness. As with any plant colony that has been brought to such a degree of variability, with only relative fixation of many new combinations of characters, there are possibilities of further development that can only be realized in later generations. The number of new combinations that might be made among the complex hybrids of different types is quite beyond computation. But it may safely be predicted that some of these combinations will produce results even more striking than any hitherto attained. As an inkling of some of the expected developments that as yet are only at their beginnings, I may add there is among my plants one that bears a sixteen-petaled flower, and which is otherwise exceedingly handsome. This did not breed true as to the production of excess petals, but there is little doubt that by selective breeding it will be possible to produce a double amaryllis which will be an entire novelty. In the matter of hardiness also, there is opportunity for great improvement. My amaryllis plants are grown out of doors, the seedlings being started in the greenhouse in boxes very much as other bulbous plants are started, but not in a high temperature. There is opportunity, however, to increase their hardiness by selection, or by crossing with some hardier species. It is true that the hybrids of Crinum and Amaryllis have hitherto been sterile, but there is reason to hope that other combinations might be found that would produce fertile offspring. These and such like developments, however, await the experiments of future seasons and future experimenters. But, even as it stands, the colony of bulbs of the amaryllis and its allies constitutes one of the most interesting groups of plants anywhere to be found.
-If no ten-foot giant has ever appeared, it is probably not so much because the human race does not have the potentialities of producing such a specimen, but that experiments in selective breeding of men for the quality of size, comparable to the hybridizations that produced the giant amaryllis, have never been carried out during a series of generations.
This text is from: Luther Burbank: his methods and discoveries and their practical application. Volume 9 Chapter 3