Trans. of the
Hort. Soc. of London ser.2: v.2: pp. 348-356 (1842)
XL. On the Improvement of the Wild Carrot.
P. P. A. Lévêque de Vilmorin, F. M. H. S.
Read March 3, 1840.
The greatest part of our kitchen garden plants, and especially those which have been brought to the highest state of perfection, and rendered the most useful, are evidently deviations from wild kinds, modified by the skill and labour of man. This may be proved by comparing together in the two different conditions, those with which we are acquainted in their wild states, the cabbage, the carrot, the turnip, &c.
This fact, considered either generally or in detail, presents several subjects for study of great interest. On the one hand, it is connected with one of the most important problems of natural philosophy, that of the laws which govern the species and its variations; on the other hand, it affects Botany properly so called, and Physiology; the former as regards the determination of the species to which the numerous cultivated varieties belong, the second as regards the changes effected in the proportions and the developement of the organs or parts of a plant. But the most interesting perhaps, and at the same time the most useful, point of view under which these modifications can be considered, is that of the means by which they have been effected.
|* M. Decandolle, I believe, is the first among the great botanists who has caused the necessity of studying these plants to be felt; he has insisted upon it in several of his works, and resolving to add application to precept, he has published an important paper on the species and varieties of the cabbage and horseradish cultivated in Europe. A very estimable and learned man, Duchesne, has with similar views studied Strawberries and Gourds, of which he has given Monographs.|
It is a nearly new enquiry with us. The habit of seeing our alimentary plants under their present forms, their utility, even the common and daily use of them, have caused them to be considered in general, as entirely natural productions, with nothing particular in their origin; neither has the curiosity of the cultivator been excited Botanists, on their side, have long scorned to give their attention to garden varieties; and they have on this account been much overlooked.*
|† Some Amateurs, who dwell in the neighbourhood of the coasts where the Sea-Kale grows, have assured me that it is not uncommon to find specimens of it, in its natural state, as fine and as much developed as those which are seen in the gardens.|
If, however, attention be confined to this subject, and we enquire how the feeble, filamentous, and scarcely fleshy tap-roots of some wild plants have been transformed into our bulky kitchen-garden roots; or how the head of the cabbage has been created; or by what process the tapering leaves upon the stalk of the wild cabbage have been agglomerated and compressed into a compact and fleshy mass, we shall find ourselves embarrassed by the enquiry. Modern horticulture, advanced as it is in many respects, presents no similar example. Some new vegetables indeed have been introduced into the gardens of our own days, or during the last century; and they have remained such, or nearly such, as they were originally. Amongst them, one may instance the Sea-Kale; the culture of which during the last 40 or 50 years has become general in England, where it is the object of much care; nevertheless, the plant has, hitherto, experienced no sensible changes in its form or its dimensions.† It is the same with Tetragonia expansa, which is now what it was at its first appearance, and of other kitchen-garden kinds of more recent introduction.
As for our old vegetables, they have been transmitted to us ready formed by the generations which have preceded us. The origin of most of them is traceable to unknown times; there are even some of which the wild sorts exist no longer, or which have not been found by botanists, and which we possess only in the domestic or cultivated state. It is very true that these plants are still in the course of improvement by us, and that we daily obtain new varieties of them; but amongst such variations of species already changed, and the first amelioration of a wild plant, a fundamental difference exists of which it is important to give some account.
When by any means, a species has been made to deviate from its primitive condition, the somewhat artificial race or races, which have resulted from it, are essentially variable. This is what we see in our garden kinds, which have a constant tendency to sport, generally in order to degenerate, (in our opinion,) that is to say, to return to their first stock; often also by contrary and different influences, (for this phenomenon is very complex in its causes as in its effects,) to wander still further from it, or to experience new changes. The natural species, on the contrary, is essentially fixed and stable; with rare exceptions, it varies only within the limits assigned to the different individuals; differences which disappear and are renewed with those individuals, without leaving any lasting traces, and without giving birth to new races.
This explains how we obtain, so easily, varieties of our kitchen-garden plants already altered and ameliorated; whilst, if we bring into culture a species still in its natural state, we do not see it sensibly improve. These improvements however are possible; they have formerly been effected by man in many species, but neither the tradition of the means, nor the practice itself, has been handed down to us.
|* Of this I have now an example before me for two years I have been trying the Brassica sylvestris, for the seeds of which I am indebted to the politeness of Mr. Loudon and the Rev. Thomas Bree; the most vigorous individuals of them are those which are the least disposed to form a head.|
It might be supposed, and this opinion has sometimes been expressed to me by sensible men, that in order to create improved alimentary varieties, nothing more has been requisite than abundant nourishment and great care in garden culture; but an attentive examination does not allow me to adopt this opinion except in a very restricted sense. Certainly care is among the number of indispensable means, but it is also beyond a doubt that of itself it is insufficient. Give to the wild cabbage very abundant nourishment, treat it with a gardener's care, you will procure for it a more vigorous developement, larger dimensions; its leaves will become more ample, its stems higher; you will convert it into the chou cavalier or the chou vert branchu; but by these means alone you will never make of it a headed cabbage.* Something else certainly has been wanting—What other thing? Or, rather what other things? That is the problem to which I invite attention, not for the cabbage only, but for very many other plants.
Being often occupied upon this enquiry, I have endeavoured to satisfy myself about it by experiments; I have pursued some upon different plants with a view to ameliorate them; upon the perennial lettuce, or Lactuca perennis, on the Tetragonia, the Solanum stoloniferum, the Brassica orientalis. Many years of trials have not enabled me, at present, to obtain any sensible modifications of these species. But the wild carrot, which I had comprised in the same trials, has improved, on the contrary, in the most decided manner; in the space of three generations I have obtained roots of it as fleshy and as large as those of the Garden carrot. I have the honour to send to the Horticultural Society some specimens of them, and I add to them as a point of comparison and that a judgment may be formed of the advance gained, some wild roots, proceeding from the same fields in which were gathered the seeds for my first trials.
This is the history of the experiment.
In March, 1832, I made, at Verrière near Paris, in a soft and deep earth, my first sowing of wild carrot. All came up; I obtained no root better than those of the fields.
In 1833, the 26 April, I tried here, at Barres, Loiret, where the earth is stronger, a new sowing. It sprung up very clean, the plants became very strong, but all still ran to flower. The roots were larger than those of the fields, but I should say, worse on account of their consistence and their strong ramifications. Two other sowings, made at Verrière the 15 May and 22 June following, also ran to flower to a great extent but not entirely. They had come up freely like the preceding, but very unequally and in succession; some seeds germinated during all the summer. Amongst these late plants, several did not run to flower and five or six made tolerably fleshy roots, about half an inch in diameter, and resembling very ordinary garden carrots.
These roots replanted the following spring produced seeds which were sown in 1835. A considerable portion of this crop still ran to seed, but the proportion was much less than it had previously been. The plant had already experienced a remarkable change; at the time of drawing them, about a fifth part was found to consist of pretty good carrots, small and middle sized, but a little fibrous, some even quite well made and good. This second generation presented a. good choice of stock plants, which were replanted and produced seed in 1836.
In 1837 I obtained from these seeds, a third generation of roots very considerably improved; many of them were very large and fleshy, some exceeded the weight of a kilogramme. The largest were in general coarse and ill shaped; but others were found perfectly good in every respect, equalling the best garden carrots. The refuse of this crop amounted to about a third part, consisting of forked branched roots; but most even of these were fleshy and eatable. Few plants ran to seed, at most not above a tenth part. In 1838 I made with the same seed a pretty considerable sowing in the fields; the majority of which has likewise yielded me very good produce.
Last year, 1839, I raised the fourth generation. The roots have been in general less large than those of 1837, because they have suffered much from drought; but the quality of the whole has been better, the proportion of had much less, and that of runaways almost nothing.
In order to explain more distinctly the progress of the principal modifications, I will here give a summary of them in another form, at the same time adding some essential details which I have purposely omitted above, to avoid too frequent repetitions.
Form and Bulk. 1st Generation 1833, five or six roots, (amongst a large number) were very indifferent, ill formed, scarcely middle-sized, but tolerably fleshy.
2nd Generation. About a fifth part of the carrots were middle-sized and small, tolerably good, some were even quite good. They were, in general, extremely long, diminishing in size too suddenly, and drawn out like long rats' tails.
3rd Generation. The general form was much less lengthened, and the roots had increased considerably in size. I speak of the mass; for some were, and still are, found very thready. Some were short, nearly of the form of the Breteuil carrot; the best being replanted and resown separately, generally reproduced this form. In this generation the proportion of good carrots was about two thirds.
4th Generation. Though the size was, as I have said, less large than in the preceding generation, the form and proportions of the root were nevertheles ameliorated; the lower part was more plump; upon the whole it was a better specimen. The refuse of this crop amounted to only about a tenth part.
Colour. The white colour and the yellow, commonly rather dark, made their appearance simultaneously, from the time of the small crop of 1833, and have done so constantly since then in all the other crops, the first being always in the larger proportion. The yellow being replanted apart, sometimes produce white in considerable numbers, and reciprocally; some yellow being almost always found in the white Crop; (this variation is likewise remarked in some of the old varieties, especially in the Breteuil.) The dark yellow began to appear in the crop of 1837, but it was very slightly reproduced. This shade is difficult to fix; it passes to the lemon colour, the white, sometimes to the pale red (orange).
Two roots of a dull violet, or the colour of wine lees, were found in the crop of 1835; they were spoiled in the winter and I was unable to obtain any race from them; 2 or 3 others appeared again in 1837, but they were so bad that we cast them aside. Many had only the neck stained with the same colour; amongst them however one was so fine and clean that I replanted it by itself. This year it yielded very few individuals of the same character; but its produce which has varied from white to lemon colour, has generally been excellent.
|* The same effect appears in a more remarkable manner in the violet carrot; under the rind, which is of a deep violet, the interior is sometimes found of a fine yellow.|
The red colour appeared for the first time in the third generation in 1837, and in very trifling proportion, perhaps one in three or four hundred. Contrary to the yellow, it became immediately fixed, the seeds of these first roots reproduced this year almost all red carrots more or less dark-coloured. They are, in general, coarse and rough on the surface. One of them, which I cut, was red only in the rind, or cortical layer, the centre was of a pale yellow.*
|† At the time of making these first trials, I wished to ascertain if shortening the stems would produce any favourable influence on the root; consequently a certain number of plants were submitted to a rigourous and successive pinching as they grew up; they were pinched off just above the neck, taking care to preserve entire the radical leaves. Thus these plants would develope neither stems nor flower branches, but the roots gained nothing by this suppression; they were not less hard than those of the individuals which had run up freely; they even appeared to us more branched.|
Disposition to run. It has been seen that at first the crop of March and of April ran to seed totally, and even those of May and June almost entirely.† This disposition became weaker in each generation in a very sensible degree, and in an almost exact relation with the enlargement of the root. In the present day the wild carrot has, in this respect, arrived at the same point as the old varieties; it no longer runs, or at least not more so than the latter. It is thus become truly biennial from being annual, which it was at starting. This effect is very remarkable, and we may reasonably conclude from thence, that naturally the carrot is in truth annual, and that cultivation alone has rendered it biennial.
At the point at which it has now arrived, the wild carrot is almost confounded with the garden carrot; nevertheless, it still retains some characters, which will perhaps be afterwards effaced, but which for this very reason it may be well to notice. Thus, it is not yet completely tap-rooted; a certain number of roots are to be found fork-shaped, and fibrous; and among the good and fleshy ones, several have a coarse, and as it were, rugged appearance on the surface. There is also something particular in the habit and aspect of the plant. When the individuals are far apart and can extend themselves freely, the petioles and the leaves lie down and display themselves almost horizontally upon the soil; the foliage is of a harsher green, and darker than in most of the old varieties. In the first year the root penetrated deeply into the earth, it was necessary to search one and sometimes two inches in order to discover the neck. This disposition is still observable, but it seems to me to diminish in proportion as the root increases in size and diminishes in length. The flesh is more compact, rather firmer, and of greater consistence than that of the garden carrots; it appears to contain less water of vegetation; it is however as easily cooked, is very sweet and of excellent quality.
From the long details into which I have entered upon this sort of creation, it must not be concluded that I consider it as a real victory; we already possess the improved carrot, under numerous forms and shades: the analogy is too great for a vegetable novelty to be perceived. It is nevertheless not impossible that from this renovated stock, if I may so call it, something of direct utility may be derived; for example, a very robust and large race, particularly appropriate to field cultivation. It is to this that I am now directing my attention, and I trust I may succeed. Even as a garden plant, it is possible that the wild carrot may furnish some interesting and good variety. Besides it is not in the light of these accessory advantages, supposing they should be realized, that this experiment ought to be considered, but rather in that of the general question respecting the modifications and amelioration of wild plants. Indeed, the study of this interesting question has been my only object in the researches of which I have now given an account.