Short-Cuts Into The Centuries To Come
Better Plants Secured By Hurrying Evolution
"With the bees buzzing about in the thousands of blossoms on your experiment farm," said a visitor, "I should think that the plants would get all mixed up; I should think that the daisies would be crossed with carnations, and the carnations with balloon flowers, and the balloon flowers with poppies, and the poppies with cactus."
If we were to watch a bee at work, we should quickly discover one reason why this does not happen-one reason, at least, why the cherries, and the prunes, and the roses, and the geraniums have not long ago been reduced to a scrambled mess. Our observation of the bee would show that, in going from flower to flower, it goes only to flowers of a kind. We should see that, if it starts in the morning with clover, it visits no other blossom during the day but clover blossoms. Or if it begins on an orange tree, it passes the cherries, the peaches, the apples and anything else which may be in bloom, but will go miles to find orange trees; or if it starts on onions, then the geraniums and the carnations and the poppies have no attraction for it. Which, by the way, is the reason that the bees produce, for themselves and for us, clover honey, and orange honey, and onion honey, each with a distinct flavor of its own. But there are other reasons why the flowers do not get mixed up. One is that while some flowers advertise to the bees, others advertise only to the humming birds-the bees can not get into the bird flowers and the birds can not get into the bee flowers; some flowers open in the early morning, and some toward noon; some bloom in April, and some in July. The pollen granules of some flowers are so large that they can not push their tubes down into the egg nests of flowers with small pistils; there are structural differences between the various families of plants which seem to make cross pollenation almost impossible; and so on through a wide range of reasons why certain plants are not readily mated with others-which will lead us, in a later chapter, into the interesting study of plant affinities.
The bees helped us to make a pink daisy because, through heredity, the daisies of our first planting gave daisy nectar, though their colors were white and orange. And in seven out of any ten experiments which we might try, we could safely entrust the work of pollenation to the bees, or birds, or other messengers with whom the plants have built up partnerships. But in those other three, the most important of the ten, perhaps, we should find that the pollenation would have to be done by hand. If, for example, we desired to effect a combination between two flowers, one of which blooms in the spring and the other in mid-summer, the bees could be of no service. We should have to take the pollen of the early blooming flower and carefully save it until it could be applied to the other. If we desired to effect a combination between a bird flower and a bee flower, even if in bloom at the same time, we should find it necessary to attend to the pollenation ourselves. If we had it in mind to effect a cross between a particularly large, insipid plum and a small, highly flavored plum on another tree, or if we desired to effect a cross between any two selected parents, we should find it necessary to do our own work of pollenation.
It would seem that much of the ingenuity evident in nature is directed toward a two-fold end: First, toward producing an endless combination of heredities in plants of the same kind-which, to give them a name, we may call crosses. And second, to prevent the combination of things out of kind-which, to distinguish them from crosses, we may call hybrids. The first aim ensures infinite variation the mixing up of parallel strains of heredity in such a way that no two living things are exactly alike, and that, in each new balance of tendencies produced, there is the possibility of an improvement. The second explains why, though all roses differ from each other, yet all are roses-why, though every living thing has its own individuality, its own personality, each bears the unmistakable characteristics of its kind.
Here and there through nature, nevertheless, are hybrids. Are these accidents-the result of some carelessness, some lapse? "In nature," said Mr. Burbank, "there are no accidents, no lapses. Everything that is, is a definite part of the Scheme of Things. "We see crossing between kinds and realize its purpose, and see its value in the Scheme, because it is going on about us always, everywhere-because it is a quick-moving process which we can observe without doubt or difficulty. But when, on the other hand, we see the provisions in nature against crossing out of kind, those numberless ingenious devices designed to prevent the production of hybrids, we have no right to conclude that hybrids are not a part of the Scheme of Things. They are-else there would be no hybrids. Crossing between things of the same kind is a continuous, active process necessary to the production of better and better individuals. Crossing out of kind is a slower process which, I believe, has just as definite an end as crossing within kinds excepting that its object, slowly and surely attained, is the production not of better individuals, but of better kinds."
Let us go back to our African daisies. If we read their history aright, there was, first, an orange flower which grew in the open veldt-a flower which accommodated itself to the peculiarities of the soil and the air in which it grew, and to its plant, insect, and animal neighbors-so that it became a thriving, successful race, each generation a little stronger-each year seeing it increase in numbers and spread in territory. In its spread, we may well imagine that the winds, or the animals, carried its seed over otherwise impassable barriers-just as human environment carries one son to New York to become a lawyer, another to Pittsburg to become a steel maker, and another to the gold fields of Nevada. Thus reaching out, always into new environments, some branch of this daisy family found itself in the midst of a clump of trees-trees which multiplied and grew till they obscured the sun and left the tiny plants in the obscurity of dense shade. As the trees grew (and just as slowly, quite likely), the daisies at thir feet accommodated themselves to their new environment-they adapted themselves to the shade and moisture-they had less competition, perhaps, from other small plants and so became less sturdy-they changed their color to the one best suited to attract available messengers of reproduction. At this point we interrupted the evolution of the African daisy by planting the white and the orange together and securing, in the pink one, an immediate blend of their divergent heredities. But it requires no stretch of the imagination to believe that, had we left them to their course, the same end would have been accomplished a century, or a thousand centuries, from now; that the same migratory tendency which took the white daisies into the woods would, in time, have brought them out of the woods and into the sunshine; or that the same tendency which got one division of the family into the woods would eventually have taken other divisions to the same woods; and that, sooner or later, there would have been white daisies growing alongside of orange daisies, so that, through the slow processes of nature, the same result which we produced by artificial means would have been achieved. And so, in all of our experiments with plants, we shall find that we are not working against evolution, but with it; that we are merely providing it with short-cuts into the centuries to come-short-cuts which do not change the final result, but only hasten its accomplishment. And who shall say that we, helping our plants to do in 1913 what without our help they might not be able to do before 3913-who shall say that we are not elements in evolution just as the bees, and the birds, and the butterflies, and the winds, and the rains, and the frosts-who shall say that our influence, inestimably greater than any other influence in the life of a plant-is not an intended part of progress in the Scheme of Things?
In hurrying evolution, we can, and do, play a more important part, even, than that of bringing about crosses, or hybrids, which the bees or the birds would never make. The greatest service which we render toward the advancement of plant life is that of selection, endless, skillful selection. The pink daisy was really, after all, the result, principally, of selection. The important thing we did was not to bring a mass of daisies together for the bees to work on; the important thing was to select orange daisies, and white daisies, with the purpose of producing a pink one. Then, with a bedful of variations, we selected again-selected, this time, for the shade we wanted, and destroyed the rest. Afterward, with that pink daisy, we began a still further course of selection, selecting the largest, the hardiest, the tallest; and no matter how long we might continue to grow pink daisies, we should keep on selecting, selecting, selecting-each step in our selection, because it has the human mind behind it-because it is actuated by purpose and desire-each step in this selection representing an advance, which, without our help, might take a hundred or a thousand years to bring about. So, in working out any ideal in plant improvement, the first factor and the last one is selection. Selection enters into the ideal itself, it enters into every step of its accomplishment, and it enters into the production of every succeeding plant which represents that accomplishment.
"If you believe that nature makes no mistakes, and has no lapses, how can you account for the evident unfitness of so many individual plants to survive-how can you account for the wastefulness and extravagance which is apparent throughout all forms of plant life? Leaving nature out of it for the moment," replied Mr. Burbank, "let us look at the work which I have been doing here for forty years. There has hardly been a time during this period when I have had less than twenty-five hundred experiments under way, and there have been seasons when from three to five thousand were in process. I estimate that, right on this three acre tract, considerably more than one hundred thousand definite, separate experiments in plant life have been conducted, in all. Some of the experiments which have taken the most time and cost the most money have produced no apparent result; and some of the results which seem most important have been achieved in the simplest way, with the least expenditure of effort. Out of the entire total of experiments tried, there have been not more than two or three thousand which, so far, have resulted in a better fruit, or a better flower, or a more marketable nut, or a more useful plant. On the other hand, I should feel repaid for all the work I have done if only a dozen of my experiments had turned out to be successes. It is the nature of experimentation-we must try many things in order to accomplish a few. And this is just exactly what is going on in nature all the time-excepting that where we might get one success out of forty failures, there might be but one out of a thousand or a million if the plants were left to work out their own improvement, unaided. Then, after all, the unsuccessful experiments are failures only in a comparative sense. If you have ever watched the bridge builders constructing a concrete causeway, you must have seen the false construction which was necessary-the stout wooden structure into which the plastic material was poured-a costly structure in itself which was put up only to be torn down. We can not call this wooden structure extravagance or waste, because it was a necessary step in the completion of the work. And so, while, in nature, we find many individuals which are weak-many steps which look like backward steps instead of forward ones-many apparent oversights, yet I prefer to believe, and my own work has shown me that this is true, that these are simply elements in a necessary scheme of false construction, without which the final object could not be achieved. The price of all progress is experiment; successful experiment is brought about, always, at a terrific expense of individual failures. But who shall say that progress, any progress, is not worth all it costs?"
Nature gets one success out of a million tries; Mr. Burbank has gotten one out of forty. The figures may not be exact, but the basic fact underlying them is none the less important. It was simply by eliminating steps and providing short-cuts, and bringing the human mind with its ideals, will, judgment and persistence into the environment of the African daisy that we were able to produce a pink one in a few months when, without our influence, nature might easily have taken till 3913.
The real work before us, then, is to study nature's processes-to learn to read the history of plants, to uncover tendencies and understand their trends-and then to provide short-cuts so that the far distant improvement may be made a matter of months, instead of centuries. These short-cuts, and their application, from this point on, will be our principal study; perhaps a single illustration here, more comprehensive than that of the daisy, will serve to give a clearer idea of their kind: Let us take, then, as a specimen, Mr. Burbank's methods in the production of a new cherry. First, as with the daisy, there must be an ideal-some particular kind of cherry of which we have made a mental blue print. Let us say that our blue print calls for a large, sweet cherry, which will ripen early and bear long-an eating cherry rather than a canning cherry, so that appearance is a great factor. The first step would be to gather in our elements; to pick out a large, beautiful cherry which, after the manner of many large, beautiful fruits, may be more or less insipid in taste; then to select another cherry, size and appearance inconsequential, which has the delightful flavor our plans and specifications call for. Let us take not one of each of these types, but a number of them, and then when they have bloomed, let us, by hand, cross them back and forth, making in all, we will say, five hundred crosses; each tied with a certain color of string for the purpose of later identification. The petals of the blossoms which we have crossed will fall away; long stems bearing green cherries will begin to take their place; and finally, the twigs which we have marked with strings will tempt us with their ripened fruit.
There is an interesting legend of the French girls who used to take apple boughs in blossom and shake the pollen over the apple flowers of another tree, a legend of the wonderful variation in the apples which they secured. And here and there in our work we shall see exceptions to the general rule, which seem to prove that the French legend perhaps was founded on fact. These exceptions, which will form the basis of an interesting series of experiments for us later, need have no bearing on our present cherry work. For, as a matter of practical fact, we shall find no outward evidence of our work. The meat of the five hundred cherries which we have crossed, we can safely assume, will taste the same, and be the same, as though we had let the bees attend to pollenation; the cherries that result will be no different in flavor or appearance than the other cherries on the tree. But inside the stony seed of each of those cherries we shall find an indelible living record of what we have done. So, disregarding the fruit, we save our five hundred cherry seeds and plant them in a shallow box until they have sprouted and then transplant them till they attain a six or eight inch growth.
So far, let us see how we have shortened nature's processes. In the first place, we have brought together a large, insipid cherry and a homely, small, sweet one, brought them from points, perhaps, two thousand miles apart. In the natural course, those two cherries would have spread; they would, eventually, have come together, no doubt; but we have brought them together without delay. Perhaps, in this, we have saved a thousand years. In bringing our two kinds of cherries together we have brought not only one of each type, but dozens, or hundreds, each selected for its size, or appearance, or some probable quality which it contains within. In this simple selection of individuals we may have saved other thousands of years. With unerring accuracy we have seen that the pollen of the two kinds has been interchanged, so that the five hundred or so resulting seeds will represent the two heredities we wish to mix-and only these. Who can estimate how long it might have taken the bees and the winds, working even in neighboring trees, to effect specific crosses with the certainty which we have assured? Now, with new heredities bundled up in our five hundred cherry stones, we plant them under every favoring condition in our shallow box, and unless mishap or accident intervenes, we get new cherry trees from all, or, at worst, lose but a few. From five hundred other cherries on a tree, leaving the birds to distribute the seed, how many seedlings will there sprout?
And now, with our sprouted cherry seedlings six inches or eight in height, with no man knows how many thousand years of nature's processes cut out, we come to the most important short-cut of all-quick fruiting, so that there may be quick selection. Grafting is no new practice. Virgil wrote verses about it: But thou shalt lend Grafts of rude arbute unto the walnut tree, Shalt bid the unfruitful plane sound apples bear, Chestnuts the beech, the ash blow white with the pear, And, under the elm, the sow on acorns fare. Pliny, within the same century, describes a cleft graft and bespeaks the following precautions: that the stock must be that of a tree suitable for the purpose; that the cleft must be taken from one that is proper for grafting; that the incision must not be made in a knot; that the graft must be from a tree which is a good bearer, and from a young shoot; that the graft must not be sharpened or pointed while the wind is blowing; that the graft should be inserted during the moon's increase; with the final warning, "A graft should not be used that is too full of sap, no, by Hercules! no more than one that is dry and parched."
"Graft close down to the trunk, the later theory of grafting has been, there the sap pressure is highest and the grafted cion has the best opportunity to live. Graft away out at the tip ends of the tree," thought Luther Burbank, "and you will save from two to seven years of time." It was the same kind of observation as that which led to the production of a spineless cactus; the same keen eye for cause and effect which showed Luther Burbank a new theory of grafting-which opened the way to a practice which makes possible, comparatively, immediate results.
Grafting close to the trunk gives the cion a better chance. "Give anything a good chance," thought Mr. Burbank, "and it takes its own time to mature. Take away that chance, and responding to the inborn tendency of every living thing to reproduce itself, it will hasten the process without waiting to accumulate strength. Therefore, if we graft away out at the tip ends of the tree, while we make it harder for the cions to exist, yet, in consequence, they will-bear us quicker fruit. Furthermore, if we graft close to the trunk we can, at best, attach but six, or eight, or a dozen cions. But if we graft out at the tip ends, we can put five hundred cions on a single tree."
Grafting was nothing new; but it remained for Luther Burbank to learn the secret of producing, by means of it, five hundred different kinds of fruit on a single tree at the same time, so that a comparative test might be made. It remained for Luther Burbank, with his theory of starving a living thing to make it hasten its reproduction, to cut from two to seven years out of the long wait for the fruit which is to tell the story of the heredities which were confined within the seed. It is possible, at this point, to give but the barest glimpse of the results which Mr. Burbank's improvements in grafting have made possible. Under the proper heading the details of method will be fully explained, together with a summary of the results of hundreds of thousands of grafts, showing that, while the average time of fruiting has been brought down to less than two seasons, in some exceptional cases Mr. Burbank has secured fruit for testing the same season that the graft was made. Here, too, it is not possible to convey more than a general idea of his plans which, in every operation, are aimed toward the end of producing the quickest possible test. Whether it be the quince seedlings bearing fruit in six months; or three-foot chestnut trees loaded down with nuts; or twelve year old walnut trees, the size of their seventy year old cousins-all through this work the plan and the method is to save time for the individual plant as well as to provide short-cuts for the process of evolution. To go back to our cherry seedling, now six inches above the ground, if we were to depend on nature's processes, by careful planting and cultivation wve might produce cherries in seven years; but by short-cutting through grafting, and short-cutting grafting itself through Mr. Burbank's plan, we shall have our cherry crosses in 1914 instead of in 1920-five hundred of them all on a single tree, so that they can be plucked and laid out, first, for a visual selection, to pick out the ones which conform to our ideas of color, and size, and beauty; and, second, for selection through taste-to find the one, or the two, or the dozen among them which come nearest the ideal of our original mental blue print. Perhaps of the five hundred cherries spread before us, none may fit the blue print; or perhaps one or two, approximating it, may show signs of further improvements which ought to be made. Eliminate the rest, and start afresh with those two-begin at the very beginning with them again-mix up their heredities with other desirable heredities from near or far, grow seedlings, produce quick fruit through grafting, and select again.
Every little bit Mr. Burbank has, as the neighbors choose to call it, a $10,000 bonfire. In such a bonfire there would be 499 cherry grafts out of the five hundred which we have just made; there would be 19,999 rose bushes which had been brought to bearing in order to find the twenty thousandth which was not burned-or perhaps twenty thousand rose bushes, the one sought for not having been worth the saving; there would be 1,500 gladiolus bulbs with an easy market value of a dollar a piece, put in the fire after the one, or the two, or the dozen best among them had been selected; there would be a thousand cactus seedlings, representing three years of care and watchfulness, but useless now, their duty done. A ten thousand dollar bonfire, indeed, without exaggeration. The builder of bridges can sell the lumber used in his false construction for seconds; and so, too, could Mr. Burbank profitably dispose of the elements of false construction in his work-those millions of seeds and bulbs and cuttings which represent second bests or poorer; but he does not; every step in the process excepting those concerning the final result is obliterated with a ruthless hand. "It is better," says Mr. Burbank, "to run the risk of losing a perfected product, through the destruction of the elements which went into it, than to issue forth to the world a lot of second bests which have within them the power of self perpetuation and multiplication, and which, if we do not destroy them now, will clutter the earth with inferiority or with mediocrity." So, we see that, while nature eventually would produce the things which we hurry her to produce, yet the improvements would find themselves in competition with the failures which they cost, the failures outnumbering the improvements, perhaps, a million to one. We see that we not only shorten the process, not only achieve a result out of every forty failures instead of every million, but we give our product the advantage of a better chance to live-we remove from it the necessity of fighting its inferiors for the food, and air, and sunlight which give it life.
This, then, is the story of the making of a new cherry to fit an ideal: First, selection of the elements; second, combining these elements; third, bringing these combinations to quick bearing; fourth, selecting one out of the five hundred; and then, selection, on and on. Interesting and wonderful as the process of pollenation is, ingenious and successful as Mr. Burbank's method of grafting is, important and highly perfected as his methods of growing and caring for seedlings are--these, after all, are but details in the process-minor details, in fact. The big element, over-towering them in importance, is selection. First, the selection of an ideal, then the selection of the elements which are to be blended to achieve it, then the selection of the resultant plant, and after that the selection of better and better individual plants to bear the fruit which reproduces the original selected ideal.
Everything we do, then, is simply done to facilitate selection. We produce new plants in enormous quantities, in order that there may be many from which to select; and having selected, we destroy nine hundred and ninety-nine one thousandths of our work. We strive all the while to produce quick results-to eliminate the long waits and to shorten those that we can not wholly eliminate-simply so that our selection may be truly comparative-as that of five hundred fruits tasted in a single afternoon, and so that lingering expectancy may not prejudice our judgment, or the result.
It took two thousand years to bring about the juicy American pear by unconscious selection-and two thousand years for the Orientals to produce the pear they liked. Yet, as plant improvement goes, the pear was quick to respond to its environment; other fruit improvements wrought through unconscious selection have taken ten times as long. On the other hand we see Luther Burbank's cherry tree, bearing more than five hundred different kinds of cherries at the same time, cherries produced to compare with a mental blue print less than three years old-cherries, from among which, one, at least, will be found, which will lead the way to the achievement of the ideal. And, similarly, in every department of plant life, whether it be in farm plants, or garden plants, or forest plants, or lawn plants, or orchard plants, or whether it be in plants which we grow for their chemical content, or for their fibers, or what-we shall find that it is possible to devise short-cuts into the centuries to come, and through combining stored up heredity with new environment, to hurry evolution to produce for us entirely new plants to meet our specific desires.
-Who shall say that progress, any progress, is not worth all it costs?
This text is from: Luther Burbank: his methods and discoveries and their practical application. Volume 1 Chapter 6