Wonders of Plant-Breeding
( Originally Published Early 1900's )[an error occurred while processing this directive]
ONLY the most limited view of plant-breeding can be given in an ordinary thesis. It would be necessary to extend the subject through many volumes to give even a general view of what has already been demonstrated, and that which the clear light of science has yet to bring forth from the depths is too extensive even for the imagination to grasp, except through a full knowledge of what practical field-work has already accomplished.
The fundamental principles of plant-breeding are simple, and may be stated in few words; the practical application of these principles demands the highest and most refined efforts of which the mind of man is capable, and no line of mental effort promises more for the elevation, advancement, prosperity, and happiness of the whole human race.
Every plant, animal, and planet occupies its place in the order of Nature by the action of two forces—the inherent constitutional life-force with all its acquired habits, the sum of which is heredity; and the numerous complicated external forces or environment. To guide the interaction of these two forces, both of which are only different expressions of the one eternal force, is, and must be, the sole object of the breeder, whether of plants or animals.
When we look about us on the plants inhabiting the earth with ourselves, and watch any species day by day, we are unable to see any change in some of them. During a lifetime, and in some cases perhaps including the full breadth of human history, no remarkable change seems to have occurred. And yet there is not to-day one plant species which has not undergone great, and to a certain extent constant change.
The life-forces of the plant in endeavoring to harmonize and adapt the action of its acquired tendencies to its surroundings may, through many generations, slowly adapt itself to the necessities of existence, yet these same accrued forces may also produce sudden, and to one not acquainted with its past history most surprising and unaccountable changes of character. The very existence of the higher orders of plants which now inhabit the earth has been secured to them only by their power of adaptation to crossings, for through the variations produced by the combination of numerous tendencies, individuals are produced which are better endowed to meet the prevailing conditions of life. Thus to Nature's persistence in crossing do we owe all that earth now produces in man, animals, or plants; and this magnificently stupendous fact may also be safely carried into the domain of chemistry as well, for what are common air and water but Nature's earlier efforts in that line, and our nourishing foods but the result of myriad complex chemical affinities of later date?
Natural and artificial crossing and hybridization are among the principal remote causes of nearly all otherwise perplexing or unaccountable sports and strange modifications, and also of many of the now well-established species. Variations, without immediate antecedent crossing, occur always and everywhere from a combination of past crossings and environments, for potential adaptations often exist through generations without becoming actual, and when we fully grasp these facts there is nothing mysterious in the sudden appearance of sports; but still further intelligent crossings produce more immediate results and of great value, not to the plant in its struggle with natural forces, but to man, by conserving and guiding its life-forces to supply him with food, clothing, and innumerable other luxuries and necessities. Plant-life is so common that one rarely stops to think how utterly dependent we are upon the quiet, but magnificently powerful work which they are constantly performing for us.
It was once thought that plants varied within the so-called species but very little, and that true species never varied. We have more lately discovered that no two plants are ever exactly alike, each one having its own individuality, and that new varieties having endowments of priceless value, and even distinct new species, can be produced by the plant-breeder with the same precision that machinery for locomotion and other useful purposes are produced by the mechanic.
The evolution and all the variations of plants are simply the means which they employ in adjusting themselves to external conditions. Each plant strives to adapt itself to environment with as little demand upon its forces as possible and still keep up in the race. The best-endowed species and individuals win the prize, and by variation as well as persistence. The constantly varying external forces to which all life is everywhere subjected demand that the inherent internal force shall always be ready to adapt itself or perish.
The combination and interaction of these innumerable forces embraced in heredity and environment have given us all our bewildering species and varieties, none of which ever did or ever will remain constant, for the inherent life-force must be pliable or outside forces will sooner or later extinguish it. Thus adaptability, as well as perseverance, is one of the prime virtues in plant as in human life.
Plant-breeding is the intelligent application of the forces of the human mind in guiding the inherent life-forces into useful directions by crossing to make perturbations or variations and new combinations of these forces, and by radically changing environments, both of which produce somewhat similar results, thus giving a broader field for selection, which again is simply the persistent application of mental force to guide and fix the perturbed life-forces in the desired channels.
Plant-breeding is in its earliest infancy. Its possibilities, and even its fundamental principles, are understood but by few; in the past it has been mostly dabbling with tremendous forces, which have been only partially appreciated, and it has yet, to approach the precision which we expect in the handling of steam or electricity, and, notwithstanding the occasional sneers of the ignorant, these silent forces embodied in plant-life have yet a part to play in the regeneration of the race which by comparison will dwarf into insignificance the services which steam and electricity have so far given. Even unconscious or half-conscious plant-breeding has been one of the greatest forces in the elevation of the race. The chemist, the mechanic have, so to speak, domesticated some of the forces of Nature, but the plant-breeder is now learning to guide even the creative forces into new and useful channels. This knowledge is a most priceless legacy, making clear, the way for some of the greatest benefits which man has ever received from any source by the study of Nature.
A general knowledge of the relations and affinities of plants will not be a sufficient equipment for the successful plant-breeder. He must be a skilful botanist and biologist, and having a definite plan, must be able to correctly estimate the action of the two fundamental forces, inherent and external, which he would guide.
The main object of crossing genera, species, or varieties is to combine various individual tendencies, thus producing a state of perturbation or partial antagonism by which these tendencies are, in later generations, dissociated and recombined in new proportions, which gives the breeder a wider field for selection; but this opens a much more difficult one—the selection and fixing of the desired new types from the mass of heterogeneous tendencies produced, for by crossing bad traits as well as good are always brought forth. The results now secured by the breeder will be in proportion to the accuracy and intensity of selection, and the length of time they are applied. By these means the best of fruits, grains, nuts, and flowers are capable of still further improvements in ways which to the thoughtless often seem unnecessary, irrelevant, or impossible.
When we capture and domesticate the various plants, the life-forces are relieved from many of the hardships of an unprotected wild condition, and have more leisure, so to speak, or, in other words, more surplus force, to be guided by the hand of man under the new environments into all the useful and beautiful new forms which are constantly appearing under cultivation, crossing, and selection. Some plants are very much more pliable than others, as the breeder soon learns. Plants having numerous representatives in various parts of the earth generally possess this adaptability in a much higher degree than the monotypic species, for having been subjected to great variations of soil, climate, and other influences, their continued existence has been secured only by the inherent habits which adaptation demanded, while the monotypic species not being able to fit themselves for their surroundings without a too radically expensive change, have continued to exist only under certain special conditions. Thus two important advantages are secured to the breeder who selects from the genera having numerous species-the advantage of natural pliability, and in the numerous species to work upon by combination for still further variations.
The plant-breeder before making combinations should with great care select the individual plants which seem best adapted to his purpose, as by this course many years of experiment and much needless expense will be avoided. The differences in the individuals which the plant-breeder has to work upon are sometimes extremely slight. The ordinary unpractised person cannot by any possibility discover the exceedingly minute variations in form, size, color, fragrance, precocity, and a thousand other characters which the practised breeder perceives by a lightning-like glance. The work is not easy, requiring an exceedingly keen perception of minute differences, great practice, and extreme care in treating the organisms operated upon, and even with all the naturally acquired variations added to those secured by scientific crossing and numerous other means the careful accumulation of slight individual differences through many generations is imperative, after which several generations are often, but not always, necessary to thoroughly "fix" the desired type for all practical purposes.
The above applies to annuals, or those plants generally reproduced by seed. The breeder of plants which can be reproduced by division has great advantage, for any valuable individual variation can be multiplied to any extent desired without the extreme care necessary in fixing by linear breeding the one which must be reproduced by seed. But even in breeding perennials the first deviations from the original form are often almost unappreciable to the perception, but by accumulating the most minute differences through many generations the deviation from the original form is often astounding. Thus by careful and intelligent breeding any peculiarity may be made permanent, and valid. new species are at times produced by the art of the breeder, and there is no known limit to the improvement of plants by education, breeding, and selection.
The plant-breeder is an explorer into the infinite. He will have "No time to make money," and his castle, the brain, must be clear and alert in throwing aside fossil ideas and rapidly replacing them with living, throbbing thought followed by action. Then, and not till then, shall he create marvels of beauty and value in new expressions of materialized force, for everything of value must be produced by the intelligent application of the forces of Nature which are always awaiting our commands.
The vast possibilities of plant-breeding can hardly be estimated. It would not be difficult for one man to breed a new rye, wheat, barley, oats, or rice which would pro-duce one grain more to each head, or a corn which would produce an extra kernel to each ear, another potato to each plant, or an apple, plum, orange, or nut to each tree.
What would be the result? In five staples only in the United States alone the inexhaustible forces of Nature would produce annually, without effort and without cost, 5,200,000 extra bushels of corn, 15,000,000 extra bushels of wheat, 20,000,000 extra bushels of oats, 1,500,000 extra bushels of barley, 21,000,000 extra bushels of potatoes.
But these vast possibilities are not alone for one year, or for our own time or race, but are beneficent legacies for every man, woman, and child who shall ever inhabit the earth. And who can estimate the elevating and refining influences and moral value of flowers with all their graceful forms and bewitching shades and combinations of colors and exquisitely varied perfumes? These silent influences are unconsciously felt even by those who do not appreciate them consciously, and thus with better and still better fruits, nuts, grains, and flowers will the earth be transformed, man's thoughts turned from the base, destructive forces into the nobler productive ones which will lift him to higher planes of action toward that happy day when man shall offer his brother man, not bullets and bayonets, but richer grains, better fruits, and fairer flowers.
Cultivation and care may help plants to do better work temporarily, but by breeding, plants may be brought into existence which will do better work always in all places and for all time. Plants are to be produced which will perform their appointed work better, quicker, and with the utmost precision.
Science sees better grains, nuts, fruits, and vegetables, all in new forms, sizes, colors, and flavors, with more nutrients and less waste, and with every injurious and poisonous quality eliminated, and with power to resist sun, wind, rain, frost, and destructive fungus and insect pests; fruits without stones, seeds, or spines; better fibre, coffee, tea, spice, rubber, oil, paper, and timber trees, and sugar, starch, color, and perfume plants. Every one of these, and ten thousand more, are within the reach of the most ordinary skill of plant-breeding.
Man is slowly learning that he too may guide the same forces which have been, through all the ages performing this beneficent work which he sees everywhere above, beneath, and around him in the vast teeming animal and plant life of the world.
These lines were penned among the heights of the Sierras, while resting on the original material from which this planet was made. Thousands of ages have passed, and it still remains unchanged. In it no fossils or any trace of past organic life are ever found, nor could any exist, for the world creative heat was too intense. Among these dizzy heights of rock, ice-cleft, glacier-plowed, and water-worn, we stand face to face with the first and latest pages of world creation, for now we see also tender and beautiful flowers adding grace of form and color to the grisly walls, and far away down the slopes stand the giant trees, oldest of all living things, embracing all of human history; but even their lives are but as a watch-tick since the stars first shone on these barren rocks, before the evolutive forces had so gloriously transfigured the face of our planet home.
THE WORK OF LUTHER BURBANK
OF the work of Luther Burbank, President David Starr Jordan of Leland Stanford Junior University, says: Years -ago in Massachusetts, he crept around in the mud half a day looking for the lone potato-ball on a plant with which he had been playing. It had been torn off by the foot of a stray cow. People said that he was a fool, not knowing that this one potato-ball was the fruition of years of labor. It was big with the potency of the Burbank potato. Later, when a prosperous nurseryman, he let go all his business to play with scissors and pollen and microscope, planting seeds and grafting bushes, then pulling them up and burning them by the thousand, meanwhile growing poorer every year, for the harder he worked the less his financial returns—then people said again he was a fool. Later, when wonderful blooms, gorgeous roses, vigorous walnuts, and flowers and fruits undreamed of, sprang up at Santa Rosa, people the world over came to see them and him and said, "Burbank is a wizard."
But when men of science, men like De Vries and his associates, came to see Burbank, they knew him for a man of science. A man of science is one who takes knowledge seriously; who, believing in the truth of human experience, trusts his life to it, and has the courage to use it in his business. All the world knows Burbank now, but there are two who found him out earlier than any one else, and who had faith in his work and his future before any one else had realized what he was doing. These two men are Judge Leib of San José and Professor Wickson of the University of California.
To understand Burbank's relation to the science of organic evolution, and to the five factors of evolution—heredity, variation, environment, selection, and isolation, on the inter-relation of which the movements of life depend,—we must first look at Burbank's method. It is simplicity itself. You can all do the same things in your own gardens. First choose the best of the plants you wish to develop. This is selection, the "magician's wand," as Youatt calls it, by which the breeder can summon up any form of animal or plant he may need for his use or his pleasure. Choose the best; destroy the others; Nature will do the rest. Like produces like; that is heredity. But heredity can be helped along by another element, crossing. Breed the best with the best. Some of the progeny will have the good qualities of both parents, some the bad. If your crosses are wide apart you may get new combinations undreamed of. Select these again. Breed from the best; ruthlessly burn up the rest. A flower is Nature's advertising medium, calling the bees to fertilize her germ cells. There were no showy flowers, flowers with petals, until after there were insects, and to please the insects is the flower's real purpose. You don't want the insects. You must manage the crossing yourself. So snip off the flowers, keep the bees away, and transfer the pollen to the right place with your own dainty fingers. This needs care, skill, patience, science—every virtue demanded by the finest art. And in this art no one has been more skilful than Luther Burbank. Crossing and selection, selection and crossing, this is the whole secret, as simple as any of all the secrets of Nature. It is her method of evolution. Arrange the conditions and Nature will do the rest. But it is one of the finest of all fine arts to arrange these conditions, to bring out the results, results all unseen before, but capable of the exactest forecast.
The commercial value of Burbank's work is great. It can be expressed only in figures far beyond its actual cost. But above all commercial values we must place Burbank's contributions to human knowledge.
Among other things, and I can enumerate but very few, Burbank has shown the plasticity of Nature. Like produces like, but not necessarily that which actually is. Children resemble their parents in this way, that they tend to do like things, to develop in like ways under like conditions. Change these conditions and all results are changed. Make conditions better, and new structures and new powers burst out. The mutations of De Vries, in Burbank's view, are the reflex of new conditions.
Burbank has -shown us that there is no limit to selection. Once started, variation can be intensified; heredity follows it, and evolution of new forms can be led on and on as far as a continuous purpose may choose to carry it.
Crossing of varieties of one species, and hybridization of distinct species are one and the same thing. Most crosses are fertile, and the results of a skilful cross save years of slow progress by selection. Crossing is to horticulture what punting is to football.
Each group of plants behaves in its own way. Each is a law unto itself. For this reason, as no simple, universal law, like the Mendean law, can be used to cover every hypothesis, a thousand seedling walnuts, descended from hybrid parents, differ from each other in a thousand ways—in every way conceivable in which walnuts can differ.
The advance of flowers, fruits, and grains beyond the primitive types is as great as the advance of palaces as compared with wigwams, of steamships as compared with dug-out canoes. In Pliny's time, the pear was a little rough fruit, not larger than an olive. In future time, we may go as far beyond the Bartlett pear as that has advanced over the crab-pear of the age of Pliny. We are now in the infancy of the work of producing domestic races of animals and plants. No one can forecast the possibilities of the future. And no one will do more than Burbank to make them actual.
Professor Hugo de Vries says : His very first contribution to the wealth of the United States was a new potato, which now bears his name. According to an official statement of the United States Department of Agriculture at Washington, made a few years ago, this Burbank potato is adding to the agricultural productivity of the country an annual amount of $17,000,000.. To convey an idea of the enormous number of Burbank potatoes, some one has calculated that if all the tubers produced in one year were arranged in a row, touching one another, the line would be thrice the distance between the earth and the moon.
Potatoes, however, are not his chief line of work. Neither do the grains nor does the corn attract his attention. They have been improved by others, and are almost everywhere the object of much work and care in this direction. Among fruit trees, on the other hand, many valuable species have hardly been given any endeavors to improve them in the same way. Apples and pears, of course, have to be ,excepted, but plums and many of the smaller kinds, such as brambles, have simply been left to themselves. The old types are cultivated everywhere, and the question, whether by the ordinary methods of hybridizing and selection, better and more yielding varieties could be won, has hardly ever been proposed.
Why should this be so I Simply on account of the idea that trees want so many years before the seedling may be judged by its fruits, and that selection is a slow process, requiring a large number of generations to produce remunerating results. The lifetime of one man would not suffice to gain any definite progress.
This, however, is not Burbank's principle. Try every-thing is his prescript ; it holds good as well for living organisms as in the realm of electricity. He only adds : Try it on the largest possible scale, bringing together from all continents and from all countries all the forms that might usefully be combined with the old types. When plums are to be ameliorated no species of the large genus should be left out of consideration. Types from foreign lands, or rare sorts, or long forgotten cultivated varieties may conceal characters that will prove to be the sources of desired ameliorations, or even, as in the case of the stoneless prune, bring wonders which nobody could expect.
His method is simplicity itself. Every one can do the same things in his garden. Selection is the choice of the best and the destruction of the others; nature does the rest. But you have to arrange the conditions, and this is one of the finest of all arts. It is the work of the genius, and the heaping up of unexpected results is a favor, which nature throws only in the lap of very few men. The commercial as well as the scientific value of Burbank's work is great, and can hardly be overestimated.