Chapter 7

From these several observations and experiments it may be seen, that it is not at all easy to keep the common varieties of cereals pure and that even the best are subject to the encroachment of impurities. Hence it is only natural that races of cereals, when cultivated without the utmost care, or even when selected without an exact knowledge of their single constituents, are always observed to be more or less in a mixed condition. Here, as everywhere with cultivated and wild plants, the systematic species consist of a number of minor types, which pertain to different countries and climates, and are growing together in the same climate and under the same external conditions. They do not mingle, nor are their differentiating characters destroyed by intercrossing. They each remain pure, and may be isolated whenever and wherever the desirability for such a proceeding should arise. The purity of [102] the races is a condition implanted in them by man, and nature always strives against this arbitrary and one-sided improvement. Numerous slight differences in characters and numerous external influences benefit the minor types and bring them into competition with the better ones. Sometimes they tend to supplant the latter wholly, but ordinarily sooner or later a state of equilibrium is reached, in which henceforth the different sorts may live together. Some are favored by warm and others by cool summers, some are injured by hard winters while others thrive then and are therefore relatively at an advantage. The mixed condition is the rule, purity is the exception.

Different sorts of cereals are not always easily distinguishable by the layman and therefore I will draw your attention to conditions in meadows, where a corresponding phenomenon can be observed in a much simpler way.

Only artificial pasture-grounds are seen to consist of a single species of grass or clover. The natural condition in meadows is the occurrence of clumps of grasses and some clovers, mixed up with perhaps twenty or more species of other genera and families. The numerical proportion of these constituents is of great interest, and has been studied at Rothamstead in England and on a number of other farms. It is [103] always changing. No two successive years show exactly the same proportions. At one time one species prevails, at another time one or two or more other species. The weather during the spring and summer benefits some and hurts others, the winter may be too cold for some, but again harmless for others, the rainfall may partly drown some species, while others remain uninjured. Some weeds may be seen flowering profusely during some years, while in other summers they are scarcely to be found in the same meadow. The whole population is in a fluctuating state, some thriving and others deteriorating. It is a continuous response to the ever changing conditions of the weather. Rarely a species is wholly annihilated, though it may apparently be so for years; but either from seeds or from rootstocks, or even from neighboring lands, it may sooner or later regain its foothold in the general struggle for life.

This phenomenon is a very curious and interesting one. The struggle for life, which plays so considerable a part in the modern theories of evolution, may be seen directly at work. It does not alter the species themselves, as is commonly supposed, but it is always changing their numerical proportion. Any lasting change in the external conditions will of course alter the average oscillation and the influence [104] of such alterations will manifest itself in most cases simply in new numerical proportions. Only extremes have extreme effects, and the chance for the weaker sorts to be completely overthrown is therefore very small.

Any one, who has the opportunity of observing a waste field during a series of years, should make notes concerning the numerical proportions of its inhabitants. Exact figures are not at all required; approximate estimates will ordinarily prove to be sufficient, if only the standard remains the same during the succeeding years.

The entire mass of historic evidence goes to prove that the same conditions have always prevailed, from the very beginning of cultivation up to the present time. The origin of the cultivation of cereals is to be sought in central Asia. The recent researches of Solms Laubach show it to be highly probable that the historic origin of the wheat cultivated in China, is the same as that of the wheat of Egypt and Europe. Remains of cereals are found in the graves of Egyptian mummies, in the mounds of waste material of the lake-dwellings of Central Europe, and figures of cereals are to be seen on old Roman coins. In the sepulchre of King Ra-n-Woser of the Fifth Dynasty of Egypt, who lived about 2000 years B.C., two [105] tombs have recently been opened by the German Oriental Society. In them were found quantities of the tares of the _Triticum dicoccum_, one of the more primitive forms of wheat. In other temples and pyramids and among the stones of the walls of Dashur and El Kab studied by Unger, different species and varieties of cereals were discovered in large quantities, that showed their identity with the present prevailing cultivated races of Egypt.

The inhabitants of the lake-dwellings in Switzerland possessed some varieties of cereals, which have entirely disappeared. They are distinguished by Heer under special names. The small barley and the small wheat of the lake-dwellers are among them. All in all there were ten well distinguished varieties of cereals, the Panicum and the Setaria or millet being of the number. Oats were evidently introduced only toward the very last of the lake-dwelling period, and rye is of far later introduction into western Europe. Similar results are attained by the examination of the cereals figured by the Romans of the same period.

All these are archaeologic facts, and give but slight indications concerning the methods of cultivation or the real condition of the cultivated races of that time. Virgil has left us some knowledge of the requirements of methodical [106] culture of cereals of his time. In his poem _Georgics_ (I. 197) the following lines are found:

_Vidi lecta din, et multo spectata labore Degenerare tamen, ni vis humana quotannis Maxima quaeque manu legeret_.

(The chosen seed, through years and labor improved, Was seen to run back, unless yearly Man selected by hand the largest and fullest of ears.)

Elsewhere Virgil and also some lines of Columella and Varro go to prove in the same way that selection was applied by the Romans to their cereals, and that it was absolutely necessary to keep their races pure. There is little doubt, but that it was the same principle as that which has led, after many centuries, to the complete isolation and improvement of the very best races of the mixed varieties. It further proves that the mixed conditions of the cereals was known to man at that time, although distinct ideas of specific marks and differences were of course still wholly lacking. It is proof also that cultivated cereals from the earliest times must have been built up of numerous elementary forms. Moreover it is very probable, that in the lapse of centuries a goodly number of such types must have disappeared. [107] Among the vanished forms are the special barley and wheat of the lake-dwellings, the remains of which have been accidentally preserved, but most of the forms must have disappeared without leaving any trace.

This inference is supported by the researches of Solms-Laubach, who found that in Abyssinia numerous primitive types of cereals are still in culture. They are not adequate to compete with our present varieties, and would no doubt also have disappeared, had they not been preserved by such quite accidental and almost primitive isolation.

Closing this somewhat long digression into history we will now resume our discussion concerning the origin of the method of selecting cereals for isolation and segregate-cultivation. Some decades after Le Couteur, this method was taken up by the celebrated breeder Patrick Sheriff of Haddington in Scotland. His belief, which was general at that time, was "That cultivation has not been found to change well defined kinds, and that improvement can be best attained by selecting new and superior varieties, which nature occasionally produces, as if inviting the husbandman to stretch forth his hand and cultivate them."

Before going into the details of Sheriff's work it is as well to say something concerning [108] the use of the word "selection." This word was used by Sheriff as seen in the quotation given, and it was obviously designed to convey the same idea as the word "lecta" in the quotation from Virgil. It was a choice of the best plants from among known mixed fields, but the chosen individuals were considered to be representatives of pure and constant races, which could only be isolated, but not ameliorated. Selection therefore, in the primitive sense of the word, is the choice of elementary species and varieties, with no other purpose than that of keeping them as pure as possible from the admixture of minor sorts. The Romans attained this end only imperfectly, simply because the laws governing the struggle for life and the competition of numerous sorts in the fields were unsuspected by them.

Le Couteur and Sheriff succeeded in the solution of the problem, because they had discovered the importance of isolation. The combination of a careful choice with subsequent isolation was all they knew about it, and it was one of the great achievements to which modern agriculture owes its success.

The other great principle was that of Vilmorin. It was the improvement within the race, or the "amelioration of the race" as it was termed by him. It was introduced into [109] England by F.F. Hallett of Brighton in Sussex, who at once called it "pedigree-culture," and produced his first new variety under the very name of "Pedigree-wheat." This principle, which yields improved strains, that are not constant but dependent on the continued and careful choice of the best plants in each succeeding generation, is now generally called "selection." But it should always be remembered that according to the historic evolution of the idea, the word has the double significance of the distinction and isolation of constant races from mixtures, and that of the choice of the best representatives of a race during all the years of its existence. Even sugar-beets, the oldest "selected" agricultural plants, are far from having freed themselves from the necessity of continuous improvement. Without this they would not remain constant, but would retrograde with great rapidity.

The double meaning of the word selection still prevailed when Darwin published his "Origin of Species." This was in the year 1859, and at that time Shirreff was the highest authority and the most successful breeder of cereals. Vilmorin's method had been applied only to beets, and Hallett had commenced his pedigree-cultures only a few years before and his first publication of the "Pedigree-wheat" [110] appeared some years later at the International Exhibition of London in 1862. Hence, whenever Darwin speaks of selection, Shirreff's use of the word may as well be meant as that of Vilmorin.

However, before going deeper into such theoretical questions, we will first consider the facts, as given by Shirreff himself.

During the best part of his life, in fact during the largest part of the first half of the nineteenth century, Shirreff worked according to a very simple principle. When quite young he had noticed that sometimes single plants having better qualities than the average were seen in the fields. He saved the grains, or sometimes the whole heads of such plants separately, and tried to multiply them in such manner as to avoid intermixtures.

His first result was the "Mungoswell's wheat." In the spring of 1819 he observed quite accidentally in a field of the farm of that name, a single plant which attracted his attention by a deeper green and by being more heavily headed out. Without going into further details, he at once chose this specimen as the starting point of a new race. He destroyed the surrounding plants so as to give it more space, applied manure to its roots, and tended it with special care. It yielded 63 heads and nearly [111] 2500 grains. All of these were sown the following fall, and likewise in the succeeding years the whole harvest was sown in separate lots. After two years of rapid multiplication it proved to be a good new variety and was brought into commerce. It has become one of the prominent varieties of wheat in East Lothian, that county of Scotland of which Haddington is the principal borough.

The grains of "Mungoswell's wheat" are whiter than those of the allied "Hunter's wheat," more rounded but otherwise of the same size acid weight. The straw is taller and stronger, and each plant produces more culms and more heads.

Shirreff assumed, that the original plant of this variety was a sport from the race in which he had found it, and that it was the only instance of this sport. He gives no details about this most interesting side of the question, omitting even to tell the name of the parent variety. He only asserts that it was seen to be better, and afterwards proved so by the appreciation of other breeders and its success in trade. He observed it to be quite constant from the beginning, no subsequent selection being needed. This important feature was simply assumed by him to be true as a matter of course.

[112] Some years afterwards, in the summer of 1824, he observed a large specimen of oats in one of the fields of the same farm. Being at that time occupied in making a standard collection of oats for a closer comparison of the varieties, he saved the seeds of that plant and sowed them in a row in his experiment-field. It yielded the largest culms of the whole collection and bore long and heavy kernels with a red streak on the concave side and it excelled all other sorts by the fine qualities of its very white meal. In the unequal length of its stalks it has however a drawback, as the field appears thinner and more meager than it is in reality. "Hopetown oats," as it is called, has found its way into culture extensively in Scotland and has even been introduced with success into England, Denmark and the United States. It has been one of the best Scottish oats for more than half a century.

The next eight years no single plant judged worthy of selection on his own farm attracted Shirreff's attention. But in the fall of 1832 he saw a beautiful plant of wheat on a neighboring farm and he secured a head of it with about 100 grains. From this he produced the "Hopetown wheat." After careful separation from the kernels this original ear was preserved, and was afterwards exhibited at the Stirling Agricultural [113] Museum. The "Hopetown wheat" has proved to be a constant variety, excelling the ordinary "Hunter's wheat" by larger grains and longer heads; it yields likewise a straw of superior quality and has become quite popular in large districts of England and Scotland, where it is known by the name of "White Hunter's" from its origin and the brilliant whiteness of its heads.

In the same way Shirreff's oats were discovered in a single plant in a field where it was isolated in order to be brought into commerce after multiplication. It has won the surname of "Make-him-rich." Nothing is on record about the details of its origin.

Four valuable new varieties of wheat and oats were obtained in this way in less than forty years. Then Shirreff changed his ideas and his method of working. Striking specimens appeared to be too rare, and the expectation of a profitable result too small. Therefore he began work on a larger scale. He sought and selected during the summer of 1857 seventy heads of wheat, each from a single plant showing some marked and presumably favorable peculiarity. These were not gathered on one field, but were brought together from all the fields to which he had access in his vicinity. The grains of each of these selected heads were [114] sown separately, and the lots compared during their whole life-period and chiefly at harvest time. Three of the lots were judged of high excellence, and they alone were propagated, and proving to be constant new varieties from the outset were given to the trade under the names of "Shirreff's bearded white," "Shirreff's bearded red," and "Pringle's wheat." They have found wide acceptance, and the first two of them are still considered by Vilmorin as belonging to the best wheats of France.

This second method of Shirreff evidently is quite analogous to the principle of Lagasca and Le Couteur. The previous assumption that new varieties with striking features were being produced by nature from time to time, was abandoned, and a systematic inquiry into the worth of all the divergent constituents of the fields was begun. Every single ear at once proved to belong to a constant and pure race, but most of these were only of average value. Some few however, excelled to a degree, which made them worth multiplying, and to be introduced into trade as separate varieties.

Once started, this new method of comparison, selection and isolated multiplication was of course capable of many improvements. The culture in the experiment-field was improved, so as to insure a fuller and more rapid growth.

[115] The ripe heads had to be measured and counted and compared with respect to their size and the number of their kernels. Qualities of grain and of meal had to be considered, and the influence of climate and soil could not be overlooked.

Concerning the real origin of his new types Shirreff seems never to have been very inquisitive. He remarks that only the best cultivated varieties have a chance to yield still better types, and that it is useless to select and sow the best heads of minor sorts. He further remarks that it is not probable that he found a new sport every time; on the contrary he assumes that his selections had been present in the field before, and during a series of succeeding generations. How many years old they were, was of course impossible to determine. But there is no reason to believe that the conditions in the fields of Scotland were different from those observed on the Isle of Jersey by Le Couteur.

In the year 1862 Shirreff devoted himself to the selection of oats, searching for the best panicles from the whole country, and comparing their offspring in his experimental garden. "Early Fellow," "Fine Fellow," "Longfellow" and "Early Angus" are very notable varieties introduced into trade in this way.

[116] Some years later Patrick Shirreff described his experiments and results in a paper entitled, "On the improvement of cereals," but the descriptions are very short, and give few details of systematic value. The leading principle, however, is clearly indicated, and anyone who studies with care his method of working, may confidently attempt to improve the varieties of his own locality in the same way.

This great principle of "variety-testing," as it has been founded by Le Couteur and Patrick Shirreff, has increased in importance ever since. Two main features are to be considered here. One is the production of local races, the other the choice of the best starting-point for hybridizing experiments, as is shown in California by the work of Luther Burbank in crossing different elementary species of _Lilium pardalinum_ and others.

Every region and locality has its own conditions of climate and soil. Any ordinary mixed race will contain some elementary forms which are better adapted to a given district, while others are more suitable to divergent conditions. Hence it can readily be inferred that the choice cannot be the same for different regions. Every region should select its own type from among the various forms, and variety testing therefore becomes a task which every [117] one must undertake under his own conditions. Some varieties will prove, after isolation, to be profitable for large districts and perhaps for whole states. Others will be found to be of more local value, but in such localities to excel all others.

As an example we may take one of the varieties of wheat originated by the Minnesota Experiment Station. Hays described it as follows. It was originated from a single plant. From among 400 plants of "Blue stem" several of the best were chosen, each growing separately, a foot apart in every direction. Each of the selected plants yielded 500 or more grains of wheat, weighing 10 or more grams. The seeds from these selected plants were raised for a few years until sufficient was obtained to sow a plot. Then for several years the new strains were grown in a field beside the parent-variety. One of them was so much superior that all others were discarded. It was the one named "Minnesota No. 169." For a large area of Minnesota this wheat seems capable of yielding at least 1 or 2 bushels more grain per acre than its parent variety, which is the best kind commonly and almost universally found on the farms in southern and central Minnesota.

It would be quite superfluous for our present purpose to give more instances. The fact of [118] the compound nature of so-called species of cultivated plants seems to be beyond all doubt, and its practical importance is quite obvious.

Acclimatization is another process, which is largely dependent on the choice of adequate varieties. This is shown on a large scale by the slow and gradual dispersion of the varieties of corn in this country. The largest types are limited to temperate and subtropical regions, while the varieties capable of cultivation in more northern latitudes are smaller in size and stature and require a smaller number of days to reach their full development from seed to seed. Northern varieties are small and short lived, but the "Forty-day-corn" or "Quarantino maize" is recorded to have existed in tropical America at the time of Columbus. In preference, or rather to the entire exclusion of taller varieties, it has thriven on the northern boundaries of the corn-growing states of Europe since the very beginning of its cultivation.

According to Naudin, the same rule prevails with melons, cucumbers and gherkins, and other instances could easily be given.

Referring now to the inferences that may be drawn from the experience of the breeders in order to elucidate the natural processes, we will return to the whitlow-grasses and pansies.

[119] Nature has constituted them as groups of slightly different constant forms, quite in the same way as wheat and oats and corn. Assuming that this happened ages ago somewhere in central Europe, it is of course probable that the same differences in respect to the influence of climatic conditions will have prevailed as with cereals. Subsequent to the period which has produced the numerous elementary species of the whitlow-grass came a period of widespread distribution. The process must have been wholly comparable with that of acclimatization. Some species must have been more adapted to northern climates, others to the soils of western or eastern regions and so on. These qualities must have decided the general lines of the distribution, and the species must have been segregated according to their respective climatic qualities, and their adaptability to soil and weather. A struggle for life and a natural selection must have accompanied and guided the distribution, but there is no reason to assume that the various forms were changed by this process, and that we see them now endowed with other qualities than they had at the outset.

Natural selection must have played, in this and in a large number of other cases, quite the same part as the artificial method of variety testing.