THE WILD OAT AS THE ORIGIN OF THE CULTIVATED VARIETIES.
Crop oats, like wheat, have ever been considered as a direct gift from
Ceres, and few, indeed, amongst scientific men were willing to believe
that they were derived from a wild and weed species. Still, the farmer
had long maintained that oats, when cultivated, often left behind them
weed oats; and in some districts of Worcester, Gloucester, and Warwick,
we have known men refuse to grow oats as a crop from their fear of
producing the terrible weed, which, indeed, the wild oat is on all hands
admitted to be.
Now, although we by no means wish to advance the theory of
transmutation, and cannot believe that by any plan barley can be
converted into oats, or oats into barley, we are yet confident that what
has been termed _ennobling_, or the producing of a cultivated plant from
a wild one, is oftentimes comparatively easy, and in none more so than
in the production of crop oats from the wild species, _Avena fatua_.
Professor Lindley, in the article “Avena,” in Morton’s _Cyclopædia of
Agriculture_, suggests that the cultivated oat “is a domesticated
variety of some wild species, and may be not improbably referred to
_Avena strigosa_, bristle-pointed oat;” but our experiments would show
that the _Avena fatua_ is the form from which at least the domestic
sorts in general cultivation seem to have sprung.
The _Avena fatua_ (wild oat) is an annual grass which almost universally
accompanies agrarian circumstances; that is to say, it seldom, if ever,
occurs in a truly wild aboriginal state, and is therefore not found in
uncultivated tracts, but is the common attendant on tillage, and in some
soils is a most common and disagreeable weed in various agricultural
crops, but more especially amid grain, whether of wheat, barley, or
oats. Sometimes it is found with beans, peas, and vetches, and, indeed,
it may be said to be a common weed in some districts in any crop from
which it has not been eradicated by the hoe—an operation almost
impossible in grain, as its growth is so much like that of the crop
itself.
It is a tall grass, rivalling the height of the finest cultivated oat
crop, from some forms of which, and especially those with a lax panicle,
it is at first not easily distinguished; however, a more careful
examination and comparison with the so-called _Avena sativa_ (cultivated
oat) enables us to make out the following differences:—
_Avena fatua, L._ _Avena fatua_, var. _sativa_.
The valves of the inner pales, The valves of the inner pales not
which adhere to the seeds, thick, not so coarse as in _A. fatua_,
and covered with stiff hairs, and quite devoid of hairs. The
especially towards the base. The outer valve with or without an
external valve has a long stiff awn, which when present is not so
awn, which in the ripe seed is stiff as in the wild plant,
usually twisted at the lower part, sometimes twisted at the base,
and bent at nearly right angles but seldom bent. Seeds large and
at about the middle. The grain- full, forming the grain for which
seed very small and worthless. the crop is cultivated.
The experiments about to be detailed were performed with the _Avena
fatua_.
In 1851, a quantity of this plant was noticed by the author on the farm
of C. Lawrence, Esq., near Cirencester. It was mixed with a patch of
mangel-wurzel which had been planted for seed; and from these specimens
sufficient seeds were preserved wherewith to sow one of our experimental
plots.
It should be noticed that the substratum was forest marble, and no doubt
the seeds of the oat were brought with the manure by which the mangold
patch was dressed.
In the spring of 1852 a plot of two and a half yards square was sown
with seed which had been kept during the winter—a fact which should be
carefully noted, as it forms a first and most important link in the
chain of evidence, and constituting what we term a cultivative process,
inasmuch as in wild growth the seeds are sown as soon as they become
ripe.
The seeds of the first crop came up well, and on ripening, towards
autumn, the plants were tall and robust; the grains presented a scarcely
appreciable difference from the wild examples; if any, there may have
been a slight tendency to an increased plumpness of grain.
The seeds of crop No. 1 were again collected and preserved throughout
the winter, and sown in a patch of similar size, but in a different part
of the garden, in the spring of 1853, repeating the process with the
successive crops in 1854 and 1855, with slight alterations from year to
year, though in some examples the following tendencies seemed from the
first to be gaining strength in some few of the specimens:—
1st. A gradual decrease in the quantity of hairs on the pales.
2nd. A more tumid grain, in which the pales were less coarse and the awn
not so strong and rigid, and less black than in the wild example.
3rd. A gradual increased development of kernel or flower.
The seeds of 1855 crop, without selection, were treated in the same
manner during the winter, and were sown in the spring of 1856, the
resulting crop in August of the same year presenting the following
curious circumstances:—
1st. _Avena fatua_ (typical wild oat), with large loose panicles of
flowers,[10] thin hairy florets, with a bent awn twisted at the base.
Five parts of crop.
[10] Some examples of this plant, gathered at Framilode, in the Vale of
Gloucester, in the past autumn, gave as many as 750 seeds to a root,
from which its rate of increase as a weed may be imagined.
2nd. _Avena fatua_, var. _sativa_, with loose panicles of flowers,
florets quite smooth, tumid, with or without straight awns, some few
examples slightly hairy towards the base. This is the potato-oat type.
Six parts of crop.
3rd. _Avena fatua_, var. _sativa_—Panicles more compact, flowers
inclining to one side, grains more tumid than 2nd, quite devoid of
hairs, awn straight. These present the type of the white Tartarian oat.
Twelve parts of crop. Fig. 2. See plate.
Having now procured a crop of separate types of oat from the same seed,
we preserved them distinct, and this year carried on our experiments by
cultivating a patch of each, whilst the plot of 1856 was left with
self-sown seeds, in order that it should again become wild by
degeneracy.
From these experiments, then, we may conclude that different types of
crop oats are derived from the _Avena fatua_, or wild oat; but, besides
this, they open out a subject for inquiry of great practical interest
and importance, which may be clearly stated as follows:—
If by cultivation the wild oat assumes the cultivated form, then by
degeneracy cultivated oats may become wild ones.
Those who know what a detestable weed is the wild oat wherever it
occurs, and how difficult it is to eradicate,[11] will at once see the
cogency of the question involved.
[11] The author once went with a rector of a parish in Gloucestershire
to examine the glebe allotments of the poor people, when, catching sight
of an apparent crop of oats, the landlord threatened to dispossess the
tenant, “because he had carelessly left his crop without gathering.”
However, the matter was explained when it was pointed out that the land
was planted with wheat, which the oats had quite smothered.
Farmers in some districts, and more especially on stiff clay soils, have
ever objected to the cultivation of oats, as they had always maintained
that they left behind a crop of weed oats. This, which was never a
favourite idea with the botanist, who is generally too much inclined to
species-making, seems now to have a basis of truth, for not only is it
confirmed by the experiments described, but observation of an
independent kind points to the same truth.
On examining the produce of shed, or accidentally scattered oat seeds,
the first crop will often present the wild tendency in a partial
reversion to the hairy state, an elongation and thickening of the awn,
and a lessening of the size of the kernel; and this more particularly on
heavy soils. It was, indeed, an observation of this change in oats
scattered on forest marble clay which induced us to try the experiments
above detailed; and as the subsoil of our botanical garden is the same
clay, we are, perhaps, indebted to this cause for arriving so soon at
such signal results.
Again, it is known in farming that some clay lands will never produce
heavy oats; a sample, however good, is sure to degenerate upon such
soils. Hence, then, the foregoing experiments and observations lead to
the following conclusions:—
1st. The wild oat is perhaps not a native of Britain, but derived
through the degeneracy of the cereal crop; and hence its occurrence only
as an agrarian.
2nd. The cereal oat, on the contrary, is the result of the impress of
cultivative processes upon the wild form, and as such liable to lapse
into the wild state with greater or less celerity, according to the
circumstances of soil and situation.
These conclusions are of practical value, as they show the direction in
which experiments should be conducted in order to attain to varieties,
it being a well-known fact that one variety is suitable for one soil,
and another for a different kind of land. And again, as some forms of
plants would seem to have the tendency of wearing out by long
cultivation, so we have the means of applying to the original source of
their production, and thus of commencing a new generation.
They teach us, too, the necessity of avoiding the growth of the oat crop
in some situations, and which in the case before us is not the result of
the “pigheadedness” with which the farmer is often so thoughtlessly
accused, but a conclusion founded in reason; and if we consider how
robust is the growth of the wild oat, and that its support is secured by
robbing the grain crop with which it occurs as a weed—the difficulty of
separating it from the crop where it has gained a footing—and, above
all, that its succession is secured by its seeds universally ripening a
few days before that of the crop with which it is mixed, and the moment
they are ripe they fall and become self-sown,[12]—we can see abundant
reason for wholesome fear as to the introduction of cereal oats in
districts liable to their degeneracy.
[12] The wild forms shed their seeds much more readily than the
cultivated ones, and are, besides, earlier in ripening, and thus much of
our wild seed had dropped before the other forms were fully ripe; and it
much assists experiments in transmutation not to let the seeds with
which they are to be carried on become dead ripe. This is another
cultivative process.
The annexed enlarged figure of a bunch of wild oat seeds will
sufficiently illustrate the changes necessary to produce the cultivated
form.
Under cultivation, which supposes the _selection, saving up, and sowing
in a prepared_ bed of our seed, the wild oat seed gradually becomes
smooth externally, and its awn less coarse, while internally the grain
becomes larger and heavier; so that while the seed of the wild oat would
weigh about 15 lb. per bushel, that of a fine sample of white cultivated
oat sown on our farm this year weighed as much as 48 lb. per bushel.
Now, the proof of this theory consists in the facts—
1st. That heavy oats degenerate by being _cultivated_ in poor soil.
2nd. By _being let go wild_, they sink still lower, and gradually assume
the external hairs, stiff awns, and poor grain of the wild oat.
[Illustration: _Spikelet of the Wild Oat._[13]]
[13] From _Popular Science Review_, vol. i. p. 10.