This section is from "The Horticulturist, And Journal Of Rural Art And Rural Taste", by P. Barry, A. J. Downing, J. Jay Smith, Peter B. Mead, F. W. Woodward, Henry T. Williams. Also available from Amazon: Horticulturist and Journal of Rural Art and Rural Taste.
The word hybrid, when correctly used, is only applied to the offspring of a mixture of two species. For instance, if we should take the native strawberry (Fragaria Virginiana) and the English strawberry (Fragaria vesca), and, by fertilizing one with the other, produce a plant with the characteristics of both parents combined, we would then have a proper hybrid. But if we take the Ho-vey strawberry and fertilize it with the Wilson, the result would only be a cross between two varieties of the same species.
This we hold to be the correct view of the case; but custom, which sometimes becomes law, has broken down this barrier, and we now call a seedling plant a hybrid, whether it be the mixture of two varieties or two species. This is to be regretted, as true hybrids are forced productions, and not natural; consequently they are very rare - so much so that we have often thought that it could be said with propriety, that species do not intermingle; and the few cases that we have on record of their having done so might be called exceptions, which are said to be necessary to every rule.
Plants in a state of nature perpetuate their species and varieties with great uniformity of character. Yet a slight change is very often observed, and it has been upon these variations that pomologists and florists have mainly depended as the starting point from which they produce their innumerable varieties.
The effects produced by change of soil and climate upon plants, when removed from their native habitat, have long been observed, and these variations turned to valuable account. Although these changes have been slow, yet, by the aid of science and the preservation of them, we are indebted for most of the valuable fruits and flowers in cultivation.
When plants are removed from one country to another, and become acclimated, the effect of this change will sometimes show itself in the seedlings grown from them, in a distinct and wonderful manner - so much so, that we are often inclined to think that it is the result of accidental hybridization.
This leads many to believe that they have a hybrid variety, when it is only a variation produced by natural causes.
If we have a variety of fruit which produces its kind without variation, it is not positive proof that it is a distinct species; but it only goes to show that the natural forces of the plant are perfectly balanced.
When there has been a displacement of these forces, either by hybridization or cultivation, and the functions of generation have been disarranged, then variation begins, and the effects of hybridization are the more difficult to determine.
Suppose we fertilize the Isabella grape with the Sweetwater, and the result is a white variety, would the simple fact of its being white be a proof that the operation had been successful? No, not at all; for there have been plenty of white varieties produced from the Isabella, without its being brought in contact with any white kind.
To convince us that hybridization has actually taken place, we would want to see some of the prominent characteristics of both parents intermingled in the offspring.
Again: if the offspring should appear to be only a reproduction of the mother plant without variation, it would not prove that hybridization had not taken place; but it would only show that there was a prepotent power in the Isabella to reproduce itself, and the influence which the artificial fertilizing had produced was entirely hidden in the present generation of seedlings. But in the next generation it might show itself distinctly without any effort on our part to bring about such a result.
A good plan of determining whether a plant is a true hybrid or a mixture of two species, is to plant a quantity of its seeds; a portion of the seedlings thus produced will be pretty sure to show some of the characteristics of the original varieties; or, in other words, the mixture will again separate, and a part will breed back each to its original progenitor.
The Allen's Hybrid grape is said to be a hybrid between the Vitis labrusca and the Vitis vinifera, two distinct species. By growing a quantity of seedlings from it, we hope to prove that this is a fact; and if our position is correct, we will find a portion of them showing more of the Vitis vinifera form than their parent, while others will show more of the Vitis labrusca character.
These difficulties which we have mentioned of determining the cause that may have produced a certain change, ought not to check us in our efforts in hybridizing. The world cares but little how a thing is produced, or where it is from, for the people* are interested only in the results.
Our greatest danger lies in the fact that partial success will often direct our thoughts into a region of false theories, from which it is difficult to extricate ourselves without unlearning all that we have previously learned.
In all our efforts at hybridizing, the adaptation of the plants to the circumstances under which they are to be grown should engage our attention.
If it is our object to produce a plant for this latitude, we should avoid, if possible, crossing with a plant that is tender or otherwise unsuitable.
The aim in all of our operations should be to develop those qualities that are valuable, and discourage those that are not, for their intercrossings will often produce an individual variety more valuable to us than either of the parents.
Again, you may take two superior varieties and cross them, and the result will be a kind that is very inferior.
It is this uncertainty that makes the operation of hybridizing plants so fascinating. If we could see exactly what the results of our labor would be, it would rob it of half of its charms.
When Lady Holland introduced the dahlia into England, in 1804, suppose some enterprising artist had undertaken to make a picture of what it would be in 1861, how near, think you, would he have approached it? He might have taken the rose, tulip, hollyhock, or any other flower of his day, and from these he might have pictured its future; but he would have never dreamed that the insignificant single dahlia before him would become, in so short a time, a flower the form of which is a true mathematical figure.
We have much at the present time to stimulate us to make extra exertions to produce new varieties of fruits. The desirable qualities of our fruits are distributed among too many varieties; and what we want now is, to bring these together and concentrate them in a less number.
We want the large size of the Union Village grape, the color of the Anna, and the rich vinous quality and hardy nature of the Delaware combined in one vine. The man who will produce such a variety (and it is possible to do it) will do his country a great favor, besides making a fortune for himself.
We want a pear as good as the Seckel, and as large as the Duchess d'Angou-16me. A Gravenstein apple that will keep at least three months longer, and not lose its flavor. A currant as large as the cherry, and as sweet as a raspberry. In fact, our wants are too numerous to mention.
Among the great perfections we have too many imperfections, and it remains with us to say whether these shall be multiplied or reduced.
There are a thousand chances that we shall descend in the scale to one that we will ascend, when we undertake to raise a new variety from seed; but that one chance was the foundation on which Knight, Van Mons, Vilmorin, and many others depended for their success when they produced the many fine fruits and flowers that we are now enjoying.
We hope every one who cultivates a fruit or flower will make an effort, the coming season, to produce some new and valuable variety by hybridization.
The seedling strawberries that I showed last year were the results of very careful hybridization, and the result was that nine-tenths of the number were of fine size, as good as the original, but only one in a hundred is of superior flavor.
[The above paper was read before the American Institute. Something to the same purpose was intended for these pages; but as this is so well done, we adopt it readily for the other. It deserves a careful perusal, and we hope will draw attention to a subject too much neglected among us. - Ed].