been experienced in propagating most of the nut trees of temperate
latitudes by budding or by grafting. This appears to be largely due to
the slow formation of callus which is to make new cell connection
between the cambium layers of host and of guest. In southern regions of
the United States the union occurs much more readily than in the north.
My experiments have been made chiefly with reference to developing
methods of propagating nut trees in the north. All of the usual methods
common among nurserymen have been practically failures, but certain
unusual methods seem to promise success.
One unusual method which was suggested at last year's meeting by our
member Mr. J. F. Jones, has given a good proportion of catches. This
consists in using wood which is more than one year old for scions. Some
of the scions of shagbark hickory from wood four, five, and even six
years of age have caught. The chief difficulty has consisted in starting
the buds of this old wood (latent buds) before vigorous sprouts from the
stock diverted all the sap. It has been necessary to give much attention
to the removal of these vigorous stock sprouts. I seem to have made the
observation that if a small side branch from old wood carries a large
terminal bud, this bud will start promptly when old wood constitutes the
rest of the scion.
A method which I employed for the first time this year, which appears to
have resulted in securing union between stock and scion, has been
employed between different species of hickory trees. It belongs among
the inarching methods in classification. It seemed probable that if a
scion were to be supplied with sufficient water to prevent drying out,
in advance of granulation-cell connection, we might meet with success.
The first line of experimentation with this idea in mind was conducted
last year. The scion when grafted upon the stock was deprived of its top
bud, and a small test tube filled with water and fitted with a rubber
cap was adjusted over the site previously occupied by the top bud. This
in practical working really did keep the cells of the scion alive and in
good condition for a long time, but there was always a tendency for the
water to become impure because of the growth of various algae and other
microbes. Evidently the water when used in this way helped to furnish a
balance between the negative and the positive sap pressures which occur
under changing conditions of barometer and temperature, and which are
influential in the matter of cellular repair. The introduction of
germicides into the water of the test tube prevented the development of
adventitious organic life, but at the same time seemed to interfere with
normal cell activity at the junction of stock and scion.
[Illustration: Dr. Morris's march method of grafting with balanced
aquarium. 1. Point of union to be covered with grafting wax after
binding with raffia. 2. Loose plug of moss to lessen evaporation. 3. A
living water plant.
The "aquarium" is made out of an ordinary large test tube. Any small
bottle would do as well.]
This method served a purpose in advancing our knowledge of the subject,
but not enough grafts caught to encourage me greatly. Following out the
same line of thought, I began this year by making union between stock
and scion according to inarch principles. The scion instead of remaining
attached to its parent plant, according to former inarching method, had
been transferred to the stock, leaving two or three inches of scion free
below the point of grafting, as illustrated in the drawing. The proximal
part of the scion was then inserted into a test tube containing water.
In this case, as with placing the test tube at the top of the scion,
difficulty was found in preventing the growth of microörganisms in the
water. The addition of benzoate of soda, borax, boracic acid, and
sulphate of copper, while preventing the development of microörganisms,
seemed also to be objectionable to the physiologic processes of the
plant. It occurred to me that the principle of the balanced aquarium
might be applied, and acting upon this idea specimens of a pond weed
(Utricularia) were introduced into the test tubes. This seemed to settle
the water question completely, but it was well along in the summer
before I made grafts and applied this principle. From one to four
leaves, or parts of leaves, were left upon grafts which were applied to
stocks according to this new inarching method. All of these leaves
remained green until autumn, and fell with other autumn leaves of the
stock. Two specimens which I have cut away for examination seemed to
show a very good union between stock and scion.
I am presenting a description of the new inarching method promptly,
before obtaining more extensive statistics, in order that members of
this society may apply it experimentally next spring. Should it succeed
according to present promise, it will allow nurserymen at least two
months of grafting season, and they will not have to rush their work. In
addition it will perhaps open up a method of grafting which may be
employed freely with nut trees in the northern states.
Another unusual method for propagating nut trees consists in
facilitating the development of adventitious buds from the roots of some
particularly desirable tree. I do not know at the present time how many
species of nut trees will develop adventitious root buds, as my
experiments have been confined to roots of the shagbark hickory, beech,
and hazel. Segments of roots of these three species when placed in sand,
allowing an inch or so to protrude, will develop adventitious buds if
they are kept warm and moist. Various lengths of root segments have been
employed, ranging from two or three inches up to two or three feet. The
beech and hazel will apparently start adventitious buds from almost any
sort of root segment; but in the shagbark hickory, adventitious buds
started best upon root segments which were more than six inches in
length and more than half an inch in diameter.
Hazels may be propagated in an unusual way from the cuttings of
branches, very much like roses, if these cuttings are placed in sand and
kept warm and moist, although they do not strike nearly so readily as
rose cuttings. I have not given much attention to this experiment in its
practical bearing, but have simply observed that hazel cuttings will
strike roots if they are particularly well cared for.
Experiments with hickories and with walnuts from branch cuttings were a
failure, but they remained alive so well and formed such good callus,
that I believe someone with steam-heated hot-house beds at his disposal
may by experimentation succeed in propagating some of these trees by
cuttings, particularly from herbaceous growth of the year, in August. As
an amateur plant physiologist I foresee what the more scientific plant
physiologists may do for this subject.
One unusual method for propagating nut trees may perhaps be described
more correctly as a method for propagating unusual nut trees, and it
opens a vista of distant horizon in horticulture. The discovery was due
to an accident, and I claim no credit beyond recognizing the
significance of an odd phenomenon.
Three years ago some pistillate chinkapin flowers which had been covered
with paper bags, were left unpollenized because I did not have pollen
enough to go round. The bags were left in place because I was busy with
other things. When these bags were removed at the end of about three
weeks, it was found that the flowers had set a full complement of nuts
without having received pollen. These nuts continued to develop and were
fertile. Some of them presented a peculiarity in growth of the
cotyledons and germ, both of which grew and protruded beyond the
involuere before the nuts were ripe, indicating that the germ had not
come to a state of rest during its usual period in the nut. This freak
appeared in only eight of the nuts, a larger number having normally
resting germs.
In all of these nuts it seemed to me we were probably dealing with
parthenogenesis. In order to make sure that no pollen had been carried
in by any sort of insect, I made check experiments last year, covering
pistillate flowers so carefully that there could be no question about
their having received no pollen. It was found that the chinkapin would
develop nuts freely in this way, and that the bitternut hickory,
shagbark hickory, and pignut (Hicoria glabra) would develop nuts
sparingly in this way.
I speak of the matter as parthenogenesis in advance of microscopic
examination of the ovules,--which will be made next year; but
parthenogenesis seems to be the most likely explanation. If this is the
case, the embryo has not been formed by the conjugation of two gametes,
as generally occurs in the algae and higher plants. It is possible that
the embryo in the unpollenized chinkapins does not originate from the
female gamete at all, but that it originates from a formative budding of
other cells in the ovule. We can speak of parthenogenesis only when the
embryo originates from a female gamete alone, _i. e._, without fusing of
protoplasmic mass of the female gamete with protoplasmic mass of the
male gamete.
Some of the nuts which I am calling parthenogens have developed plants
this year. The chief peculiarity to be observed is great disparity in
size between plants of the same age from the same parent tree. Some of
them grow very much more rapidly than the average plant of the species,
and others less rapidly when subjected to similar conditions of soil,
temperature and moisture.
We assume in biology that one of nature's objects in having two sexes is
to prevent early senescence of the allotment of protoplasm for a
species, and to avoid undue intensification of characteristics of one
parent. This is apparently nature's device for maintaining a mean type.
For man's purposes we may now make artificial selection of individual
plants which represent intensification of desirable characteristics of
one parent. The growing of trees from unfertilized ovules will
apparently open an entirely new field in horticulture, and no one can
prophesy the result of selection of trees which present intensification
of desirable characteristics of a single parent through several
successive generations.
THE POSSIBILITIES OF NUT CULTURE IN UTAH
LEON D. BATCHELOR, UTAH
I suppose the majority of you have very little or no idea of
agricultural conditions in Utah. Perhaps some think it is a desert. When
I went to Utah, three or four years ago, the first thing that struck my
mind forcibly in traveling around through the state was the absolute
lack of any nuts. Being born and brought up in Massachusetts, I
naturally noticed this, as one of the pleasures of my boyhood days
consisted in gathering chestnuts, hickory nuts, hazelnuts and
beechnuts. We found them all around the fence corners and pastures and
in the woods, and I missed this in Utah, and it occurred to me
immediately to look up the cause of the lack of nuts in the state and I
found no good reason except that nature has not seen fit to plant nuts
there. There is no reason in climatic or soil conditions which will make
it impossible to grow many of the hardier nuts, and even, in the
southern part of the state, to grow almonds and the tenderest walnuts.
Climatic conditions are not unlike some of the best fruit sections in
New York. Peaches and apples are grown successfully and as soon as you
get down to the central and southern part of the state, many of the
hardier European grapes are grown. In the extreme southern part you can
grow any of the European grapes grown in California, so nothing in the
way of climatic conditions exists which would prevent the development of
nut growing in this state. The soil conditions vary widely, all the way
from the sandy loams to the deep soils and gravels, and it is possible
to find thousands of acres of deep, rich loam soil. Some of it is five
to twenty-five feet deep. Of course the rainfall in that semi-arid
region is insufficient for nuts but that can be supplemented by
irrigation water, so that is practically no disadvantage. Since I have
been there I have tried to interest some of the fruit growers in the
planting of a few different varieties of the hardier nuts, and I have
distributed among them some of the walnuts and this year I am bringing
in some of the old shagbark hickory nuts from Massachusetts, and I am
going to distribute them among my friends and acquaintances there to be
used to raise shade trees--trees around the home and pastures--and I
find there is considerable interest manifested in the last few years in
nut planting. The nut industry has a little mite of a start there in a
way--that is, there are a few seedling trees distributed from Logan on
the north to Arizona on the south. Seedling Persian walnuts fruit from
Brigham City on through Salt Lake and Provo, and practically all of the
nuts that are produced there in the state are of seedling origin. It is
reasonable to expect that some of the best grafted varieties will be
very much better. It seems to me that the state has every natural
condition for success in the production of nuts. If not in a commercial
way we can do a great deal to our advantage in planting nut trees as
shade trees. I simply want to let you know that there is a man out there
in the mountain section who is interested in nuts and going to help the
cause along.
THE DISEASES OF NUT TREES
M. B. WAITE, WASHINGTON, D. C.
In taking up the question of nut diseases it is hardly proper, perhaps,
to take too narrow a view of it and I will, therefore, mention some of
the other work being done here in Washington that is of interest to the
Northern Nut Growers Association.
You all know of the pomological work being done on nuts, and I hardly
need mention the work now being carried on by Mr. C. A. Reed, a member
of this association. It might be well to remind you that the work was
started by Mr. Van Deman some twenty-five years ago, and continued by
Mr. Corsa, and a report was issued some fifteen years ago. It was taken
up later by Mr. William A. Taylor.
The plant introduction work of Mr. D. G. Fairchild should be mentioned.
He is scouring the world for new nuts of all kinds for the northern and
southern, eastern and western United States, and introducing them into
this country. The diseases of those nuts are studied by Mr. Orton in the
Cotton Truck Division of our department.
Outside of the Bureau of Plant Industry also there is some work being
done on nut trees. The insects attacking cultivated nuts are studied by
Professor A. L. Quaintance, of the Bureau of Entomology, along with the
deciduous fruit insects. The insects attacking forest nut trees are
studied by Dr. Hopkins of the same Bureau in the laboratory that studies
the forest insects. Of course the nut trees, as forest trees, are
studied in the Forest Service about which you all know.
One thing more that I would like to say, in way of explanation or
apology, is in regard to criticism of the Department for not more
thoroughly attacking the filbert blight. Only forty-five thousand
dollars are appropriated by Congress for the investigation of the entire
fruit disease problem of the United States. That includes the great
citrus industry; everything, in fact, from cranberries on Cape Cod and
the mouth of the Columbia River to grape fruit in Florida or apples in
New York. It includes the subject of all the nut diseases, and that
means the problem of the diseases of the pecan, of walnut
bacteriosis--that is a big problem--in southern California, and more or
less in other parts of California, our great apple industry, the peach
yellows, the pear blight, etc. When it comes to parceling that out it
only leaves about three thousand dollars for nut diseases, and
thirty-five hundred dollars for studying diseases of citrus fruits, so
you must not be surprised that we cannot put a group of men on this
problem and study it as it should be studied. It is a question of men
and means.
Perhaps now some general information might be of interest and set you to
thinking.
In the first place in every disease problem, conspicuously so with our
fruit and nut diseases, there are two main classes of plants to be
considered, our native plants and the foreign plants. The pathologist is
always looking to the native origin of a plant in studying its
adaptation to the environment in which it is attempted to be grown. A
foreign plant may not necessarily be unadapted to another locality. The
vinifera grape is thoroughly adapted to California and to much of the
Pacific slope beyond the Rocky Mountains, but you know the vinifera
grape has a hard struggle in other parts of the United States. This is
not only a pathological problem but a physiological one. It cannot stand
a soaking rain for two weeks at a time; it cannot stand so much water
and humidity but it wants dry, hot sunshine continuously from the time
it puts out its leaves in the spring.
Another phase still more interesting is the question of foreign
parasites. Many of the worst diseases with which we have to contend are
either native diseases attacking introduced plants, or foreign diseases
attacking native plants. I will take that up in detail. Nature has
fought the battle all out with the native parasites against the native
host plants, so we don't have to do it. It's a case of the survival of
the fittest. They have won, so when we are dealing with native plants
against our native diseases, we have a condition that has been fought
out in nature for nobody knows how many thousand years. The result is
that unless we disturb the balance too much by cultivating great
orchards of a thing that has been grown as scattered individuals, or
overforcing it or selecting and breeding towards larger fruit without
any regard to foliage and other characters we can go ahead with our
breeding and selection and cultivation and trust nature to keep the
balance to some extent. We have this natural balance in our favor in
dealing with the problem of cultivating native plants. As an example
take the pear and apple blight. The pear blight problem is one in which
a native parasite on wild crab apples, which occasionally kills a few
twigs here and there, attacks the juicy, tender, susceptible, introduced
European pear and makes a very serious disease. It is a fight indeed to
grow it in so much of the country that pear culture has been very
largely suppressed over the eastern half of the United States and part
of the Pacific coast. All this trouble has been caused by one little
native microbe. Apple culture also, with certain varieties, has been
seriously interfered with in some sections.
The apple cedar rust is probably the most striking example of a native
parasite attacking a foreign host that we know of, and particularly so
as the remarkable evolution in which the parasite has adjusted itself to
the new host is taking place right now every year. The apple cedar rust
is becoming a more difficult problem clear across the eastern United
States to Nebraska. It has occurred as a serious disease since 1905 to
1907. As a botanical curiosity we have known it a long time, but as a
serious disease, it is very recent, and nobody knows yet how serious it
is going to be.
We have a very striking example of this introduction of a foreign plant
and the plant being attacked by a native parasite, in the case of the
filbert blight, and I am going to take that up later. The trouble is
that we have brought into the United States a European filbert and it
has been attacked by a parasite of our wild hazelnuts. The disease is
very rare and is seldom seen on the wild hazelnut,--so rare that it was
hardly known by scientific botanists, and yet it interferes with filbert
culture in the eastern United States and is the one thing more than
anything else to make filbert culture unprofitable. We have practically
the same proposition in the walnut bacteriosis, not only in the
northeastern United States, but in the best walnut districts of
California. This bacterial disease which is undoubtedly a disease of our
native walnuts--probably the native black walnut--occurs rather rarely,
and so feebly developed as to be difficult to find at all on its native
host yet it becomes the great serious disease of the Old World
cultivated walnut.
Now, there again, it is not so much a lack of physiological
adaptability, because the walnut is thoroughly adapted to our Pacific
coast. I suppose most of you know that east of the Rocky Mountains, east
of the Great Plains, we have a humid climate and winters more or less
cold which corresponds, not with western Europe, not with Germany,
England, Spain, France and Italy, but with China and Japan, with Asia,
in its climatic conditions. The result is the Chinese and Japanese trees
brought to the eastern United States grow well but may grow
indifferently in California. On the other hand, the plants of the
Mediterranean, France, Germany, Italy and Spain do not, as a rule,
thrive when introduced into the eastern United States. There are a few
exceptions, like the apple and perhaps the peach. These are not really
natives of western Europe, but have been brought from the interior. They
are more like the Japanese and Chinese plants which came in by way of
Persia and which have been slowly adjusted to the conditions of western
Europe. That adjustment has gone so far that the Persian type of peach
does better on the Pacific coast than in the East. We are breeding a
race of these fruits from China, the Chinese cling group, which does
well in the eastern part of the United States, and we have from there a
peach that is better for the country east of the Rocky Mountains than
the ones that have been modified in Europe.
Now take the other side of this question, the foreign parasite--that is
very unfortunate thing--over which we do not always have the control
that we do with the foreign host. An equal disturbance of nature takes
place when we introduce a foreign parasite, whether it is from a similar
climatic region or one not so similar. The chestnut blight is a
tremendous example of that sort of thing. This has come into prominence
within a decade and it is one of the greatest problems in the pathology
of the chestnut. That has turned out to be a Chinese parasite. It was
found last summer by the agricultural explorer, Mr. Myers, but the
fungus was studied out by Dr. Shear.
The three great American parasites of our native grapes are the black
rot, the downy mildew and the Phylloxera, an insect pest, and they
caused a great amount of study and work and investigation and great
expense when they were introduced into France and South Germany and
Italian vineyards, and were fought out only by what might be considered
a magnificent effort on the part of the European governments, especially
France. On our native wild grapes those diseases are almost trivial, and
the wild seedlings in the woods are practically immune, but when we
cultivate them and select the tenderer varieties, the black rot is
pretty bad, especially on the Concord, and particularly when that is
hybridized with grapes of European blood. Nevertheless, we have
cultivated them in order to get the large juicy fruits. There are many
more examples of this sort.
Now about the cultivated nuts. I wish I could tell you how much I think
of the native nuts. I grew up in Northern Illinois and could go out on a
day like this and gather two or three bushels of hickory nuts. How I
enjoyed the black walnut, especially when it was just shriveled so it
would leave the shell--it got rather too rich when it was dried and
stale in the winter time--but how delicious it was when just wilted!
Also there was the butternut and the wild hazelnut. I used to take a
one-horse wagon into the woods on a Saturday and gather enough hazelnuts
in the shucks to fill it; then we had hazelnuts all winter. So I am in
full sympathy with the Northern Nut Growers Association and I would
like to see those nuts grown, if not wild in the woods, at least in
cultivation.
There might be a few things of interest to you about the wild hickory
nut. According to Farlow's Index of North American fungi of twenty-five
years ago, there have been thirty-seven species of fungi collected on
that tree. Probably there are twice that number as a matter of fact, but
mycologists have collected, described and named thirty-seven species on
the _Hickoria ovata_, the plain shagbark, and the other hickories have
similar numbers. The pecan has only three named species in Farlow's
Index, but Mr. Rand has got together three times as many I think--I am
not sure of the number.