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THE. RELATION OF STOCK AND
CION EFFECTS TO WINTER
HENRY ”V THE APPLE

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Thesis for the. Degree of M. S.
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THE RELATION OF STOCK AND CION EFFECTS

T0 WINTER INJURY IN THE APPLE

by

Noel Etienne Dore
“—N

A THESIS

Submitted to the Graduate School of Michigan State College
of Agriculture and Applied Science in partial ful-
filment of the requirements for the degree of

MASTER OF SCIENCE

Department of Horticulture

Way]; 443%

//." EMA...

1939

TH E515

TABLE OF CONTENTS

I. Introduction
II. Origin of Grafting
III. Relation of maturity to Hardiness
IV. Distinction Between Hardiness of the Whole Tree and Hardiness
of the Cion Itself
V. Review of Literature, to 1900
a. Stock's communication of its own hardiness
b. Gain of vigor by grafting as affecting hardiness
c. Earlier maturity as affecting hardiness
d. Grafting as affecting hardiness of the tree
e. Top working vs. root grafting as affecting hardiness and
longevity of the tree
f. Effect of cion on hardiness of stock
g. Conclusions
VI. Feview of Literature, from 1900
a. Double working in relation to winter injury
b. Hardiness and reciprocal influence of stock and cion
VII. Conclusion

VIII. Bibliography

.4, 53".“: 15‘" ‘3
42‘5“,ng _- \I I.“

Page

01

10

12

21

27

28

THE RELATION OF STOCK AND CION EFFECTS

TO WINTER INJURY IN THE APPLE

Introduction

A review of reports on winter injuries in any particular section of .

the United States and Canada shows that the fruit growers experience,

every six to ten years, or more often, what is called a test winter and

suffer very serious damage in their orchards.

Wide and general damage

of the severe test winter of 1955—54 in Eastern Canada and in the Norih~

eastern States will long be remembered by producers who went through that

winter.

Table I is taken fron the data in "The Apple Crop Production

and Distribution for 1955" presented by the Dominion Department of

Agriculture.

The figures on the commercial production of apples give an

idea of the acuteness of the hardiness problem for the apple grower of

the Provinces of Quebec and Ontario.

Table I. - Commercial Production of Apples in 1000 Barrels

 

 

 

5-year ave.
Province 1950—51 1951-52 1952-55 1955—54 1929—55 1954-55
Quebec 129 201 258 507 216 121
Ontario 657 976 918 1,069 896 521

 

 

 

 

 

 

 

These figures show drastic reductions of 70% and 60.5% below 1955

and 44% and 65.6% below the five year averages for Ontario and Quebec,

respectively.

When one considers the increasing trend in production in

the two Provinces, especially Quebec, the figures are still more significant.

-2...

After a survey in Eastern Canada, Blair (4) listed in order of
their importance the different forms of winter killing found in the
orchards, as follows: "1. Trunk and body injury, 2. crotch injury,

5. sunscald, 4. bark splitting, 5. killing of dormant buds, 6. killing
bark, 7. black heart, 8. discoloration of the sap wood, and 9. trunk
splitting." As stated by Blair, the most prevalent injury was to the
trunk and at the crotches. More specifically, "the part of the trunk
between the snow line and a few feet up the branches was responsible
for the majority of the tree losses." This suggests that a substitution
of hardy tissues by means of a hardy stock at those weak spots would
have helped to overcome the permanent damage to a great extent. This!
idea of double working and top grafting to provide hardy trunk or
scaffold is by no means new, as it was a common practice in Iowa as
earLy as 1870.

Budd (ll) of Iowa in 1885 wrote: "While top working has been
discussed from a theoretical standpoint, and some half doubtful evidence
for many years, we can now, I believe, lay it down as an accepted doctrine
that top working varieties as hardy as Willow on stocks not subject to
stem injury will add to the longevity and productiveness of our orchard
trees. The selection of best stock should now have our special attention."
Six years earlier (1879) Budd (9) is reported as saying that the question
of influence of stock on cion has been extensiver discussed by practical
fruit growers and even respectable biologists for the past hundred years.
He considers that the main utility of the hardy stocks for top working
is to enable the less hardy cion to endure the test winters of Iowa.

Bradford and Cardinell (7) report that, in Michigan, even in the

early fifties, few growers and nurserymen realized the possibility

- 5 -

offered by working the tender varieties into frameworks formed of
varieties known to be hardy.

The possibility of growing semi—hardy varieties of apple farther
North than their normal range by means of suitable hardy rootstocks
and intermediate stock, may be considered as the practical application
associated with "the relation of stock and cion effects to winter injury".
A review of literature is undertaken on the relation of stock and cion
to cold hardiness. Attention will be given to the evidence or simple
observations tending to show the reality or non-existence of the
influence of the rootstock or intermediate stock, or both, on the hardi—
ness of the whole tree, or of the cion alone. The reciprocal effect
of the cion on the resistance to cold of the stock or stocks will receive
due attention.

The purpose of this review, however, is not so much to offer an
explanation of the phenomenon, as to assemble and present what information
is already available, in the hope that it may prove helpful in future
investigations of the problem of stock and cion as related to hardiness
in fruit trees, especially apples.

Origin of Grafting

The actual time of the beginning of grafting is unknown. As an art,
it appears to be of the remotest antiquity. From history, as Daniel (20)
reports, one learns that this art was known by the Chinese 6000 years
B. C. The Phoenecians, the Carthagenians, the Arabs, the Greeks and the
Romans employed our present methods of grafting, even many of its aspects
which are considered as recent discoveries.

One may suppose that with the practice of the art of grafting the

human mind, always inquisitive, must have wondered about the influence

- 4 -

of the stock on the cion. It is also conceivable that those people who
were near the thermal limits of certain species or varieties of fruits
questioned themselves as to whether it would be possible to grow on their
own land, in their own regions, those desirable fruits which were
flourishing in the gardens of their foreign neighbors who were enjoying

a more temperate climate. That they took recourse to the art of graft—
ing, hoping to produce the fruits they desired, is likely.

The Ancients, as the Moderns, studied the nature of the association
between the stock and the cion, but the discussions were metaphysical
rather than scientific until and during the Middle Ages. It is just
recently that the question of the reciprocal influence of stock and cion
began to be systematically studied by the botanists and horticulturists.
One must not be surprised then to see in a review of literature the
divergent opinions held on the subject and "a fortiori", when one remembers
that many of the observations reported were not made by men with scientific
training and the ability to make the results of their work very reliable.
In many cases at least, on account of the ignorance or carelessness of
the observers, the effects attributed to grafting or stock must be
explained by other causes. This is more likely to happen when one deals
with the hardiness of the fruit trees which can be affected by so many
factors outside the possible effect of the stock.

Relation of Maturity to Hardiness

By far the most important factor determining whether a tree is injured
at a given temperature is the degree of maturity of its tissues. Emerson
(27) says "Resistance to cold in trees is due often almost wholly to the
habit of early maturity rather than to constitutional hardiness........

Northern trees are constitutionally no hardier than Southern but their

- 5 -

superior resistance to winter cold was due to their habit of ripening
their new growth perfectly in the fall." As hardiness,within certain
limits, is a function of maturity of tissues it might be inferred that
anything which affects maturity of tissue will affect hardiness. Then
if a stock can induce earlier maturity it may affect hardiness. Hardi—
ness and maturity in fruit trees being so associated, any evidence of
the effect of stock on maturity of tissue of cion should receive
Special attention. ‘
Distinction Between Hardiness of the Whole Tree
and Hardiness of the Cion Itself

Very frequently the hardiness of the whole tree, resulting from the
symbiosis of stock and cion, is not distinguished from the hardiness
of the cion or the grafted variety alone. This lack of precise definition
of the problem is responsible for a part of the conflict of evidence or
observation that one finds on the effect of stock on hardiness. To make
such a distinction is to see that certain contradictory opinions are
not real and thus to bring more consistency into the evidence. A
grafted tree may be hardier just because a weak part, either the root
or the trunk or the crotches, has been replaced by a hardier one, the
hardiness of the cion being unchanged.

Review of Literature, to 1900

A great majority of the articles written on grafting, before the last
century, deal with the methods of doing it and are descriptive of the
same. A lesser number of these articles deals with the effect of graft-
ing on the vigor and the habit of growth of the tree, on the color,
flavor, and maturity of the fruit, on the adaptation of the tree to soil

and climate. The effect of the cion on the stock is seldom discussed.

_ 5 _

The first mention in English of the influence or use of stock to
adapt fruit trees to a colder climate is found in Philip Miller's
"Gardener's Dictionary" (55), second edition, 1755. In his article
on grafting, he says "....and it is by this Method that many Kinds of
Exotick Trees are not only propagated, but also render'd hardy enough
to endure the Cold of our Climate in the open Air; for being grafted
upon Stocks of the same Sort which are hardy, the Grafts are render'd
more capable to endure the Cold; as hath been experimen'd in most of our
valuable Fruits now in England, which were formerly transplanted hither
from more Southerly Climates, and were at first too impation of our Cold
to succeed well abroad, but have been by Budding or Grafting upon more
hardy Trees, render'd capable of resisting our severest Cold." Obviously,
Miller believed that the hardy stock communicated a part of its own
hardiness to the cion: "The Grafts are render'd more capable to endure
the Cold."

Chronologically the next opinion found on the subject, almost a
hundred.years later, is by Knight (44) in his Horticultural Papers:
"Many gardeners entertain an opinion that the stock communicates a portion
of its own power to bear cold without injury to the species or variety
of fruit which is grafted upon it, but I have ample reason to believe
that the opinion is wholly erroneous....." Knight, who probably made
more experiments and observations in grafting than any man of his time,
holds that the hardiness of the stock is not communicable to the cion.
This great horticulturist seems to be in contradiction with the idea of
Miller and, as he himself says, with many gardeners of his time.

Before a discussion of these two divergent opinions, it is worth

while to note the various opinions which have been held, and the evidence

_ 7 _

on which they have been based, prior to the beginning of this century.
For the sake of clarity, these opinions may be placed in two main
groups: Those holding that the cion tissues might be influenced in
their hardiness by the stock, and those who hold that the stock can
not have such an influence. Among the former some claim an effect of
stock on the hardiness of the cion, due to communication of its own
hardiness or to some change in the habit of growth as increase in
vigor, dwarfing effect, or to earlier maturity of the cion wood.
~Stock's communication of its own hardiness

That the stock could communicate a part of its own hardiness to
the cion, no clear direct opinion of this sort was found. On the other
hand, Fuller, Hovey, Budd, Lathrop and Lindley, as we shall see later,
declare, like Knight, cited above, that there is not such an influence.
Gain in vigor by grafting as affectingghardiness

As the result of some observations upon young trees in the Arnold
Arboretum of Cambridge, Massachusetts, Jack (45) associates a gain in
hardiness in grafted Oak and grafted Ash to an increase' in vigor
brought about by the stock. "The dwarf Qpercus geoggiana upon its
own root grew more slowly and was less hardy than when grafted on

_Qgercus robur. The stocks in this case increased in diameter more

 

rapidly than the grafts. Fraxinus anomala, a southwestern species,
also grew more rapidly and was more hardy when grafted upon Fraxinus
americana than when grown as seedlings."

Wetherell (66) claims that Magnolia glauca, when grafted on
Magnolia acuminata, will reach three times its ordinary size and be
more hardy. However, Hovey (42) admits the increase in size gained by

various other magnolias when grafted on Magnolia acuminata but denies

_ 8 _

that there is any gain in hardiness thereby.
Earlier maturity as affecting hardiness

As we shall see later, it has not been proved yet that the stock
may'increase the hardiness of the cion tissue except in so far as it
might affect the habit of growth or more especially by hastening the
maturity of the wood of the cion. Fuller (52) said "the hardiness of
a tree is but slightly changed by the stock except as its growth is
influenced to mature early or late in the season."

Gideon (55) claims that the crab apple and hardy hybrids make a
brief vigorous growth and as they naturally ripen their wood early in
the fall, the tendency is for them to force the top to ripen early
enough to avoid injury.

With the peach, Matthews (55) states that it does better on plum
stocks than on peach stocks because it seems to ripen earlier and stand
the winter better.

An unusual experience worth quoting is reported in 1885 by Cotta
(19): "During the last four years I have top worked perhaps five
or six thousand trees in nursery, using only ironclads for stems. The
results have been surprising.....They all made a fine growth the follow-
ing summer and passed the winter of 1882—1885 in first class condition,
not a bud being killed. Most of them were taken up and sold. They all
grew finely the following year, and are all right todanyJanuary, lBBE/fl

"Now compare my record of root grafted trees, standing on the same
plat, under the same condition of soil, cultivation, etc. in the spring
of 1885.

"Uninjured - Duchess, Tetofsky, Whitney and the crabs

- 9 _

"Considerably injured - Walbridge, Nelson' Sweet, Wealthy,
Haas, Shiawassee, Beauty and Fameuse

"Severely damaged - Early Harvest, Red Astrachan, Sweet June,

 

Bailey Sweet, ...., Pewaukee and Tolman Sweet

"Partly killed — Sweet Pear, Prices Sweet, ...., Ben Davis

 

"All killed — Hill's Red, Colburn, Koshkamong and Willow

 

Twig."

Should we attribute all this to the effect of a hardy stock or,
partially at least, to a result brought about by the operation of top
working and root grafting. Due to the difference in cutting back,
the root grafted tree might have responded by a more succulent growth
of the cions, which grew later in the season than in the top grafted
trees and did not have as much time to mature their wood to the same
extent as the top worked trees. They were consequently less hardy
and more likely to be injured by the cold weather of the following
autumn or early part of the winter. Here again, as in so many cases,
a distinction must be made between the effects of the process itself
and the effects of the material used in the process.

Grafting as affecting the hardiness of the tree

It is interesting to cite the opinion of Downing (26). In the
1869 edition of "Fruits and Fruit Trees of America", he says: "A
variety of fruit which is found rather tender for a certain climate
or a peculiar neighborhood is frequently acclimatized by grafting it
on a native stock of very hardy habits." Without going any farther,
one might say that Downing was talking about the influence of the

stock on the hardiness of the cion, but such does not seem to be the

_ 10 -

case because on the next page he says: "If our soil or climate
is unfavourable we use a stock which is adapted to the soil, or
which will by its hardier root endure cold."

Thomas (64), as Downing, claims that trees are made hardier
by being grafted on hardier stock.

Loudon (47) had the idea that a tree with a tender root is
made hardier when grafted on a hardy stock.

Lindley (46), in "The Theory of Horticulture", wrote: "It
is sometime desirable to increase the hardiness of a variety, and
grafting or budding appear to produce this effect to a certain
extent, not, indeed by the stock communicating to the cion any of
its own power of resisting to cold, but by the stock better
suited to the soil of latitudes colder than that from which the
cion comes and consequently requiring a lower bottom-heat to
arouse its excitability."
Top workinggvs. root ggafting as affecting_hardiness and lgggevity
of the tree

In different periodicals and horticultural society reports
one finds opinions like the following on the advantages of top
working or double working. Hanford (57) of Wisconsin considers:
"Baldwin root grafted, tender in nursery, bark splits and top kills
back, worked high seems hardy. Esopus Spitzenburg same as Baldwin,
Roxbury Russet tender if root worked, stock worked is more hardy."

Beal (5) in Michigan believed that Baldwin at least in some
cases is more hardy in cold climates when top worked upon a hardy

tree.

_ 11 -

Fluke (SO) in Iowa during a discussion at a meeting of the
State Horticultural Society'stated: "I have Stark, top worked
in perfect condition, while the root grafted trees are dead."
Later (51) he argues that in his experience some tender varieties
are rendered more hardy by being grafted upon hardy stocks.

Corbett (18) remarked that even in West Virginia top working
can be made profitable to increase the longevity of trees.

In The Country Gentleman (l) the editor in an article on the
effect of grafting says: "It has been found in Iowa, Quebec,
Vermont and other semi—artic countries that comparatively tender
varieties of apple (.......) can be grown from 100 to 200 miles
further North when top grafted on such 'ironclads' as Hibernal,
Duchess or even Tolman."

Budd (10) of Iowa found that Jonathan and Dominie will do
well on hardy early maturing stocks like Gros Pommier and Duchess
but fail when root grafted.

Powell (58) of Delaware in an early bulletin of the Station
claims that top working provides a healthy strong trunk for all
varieties, corrects the poor growth of some and overcomes the
tenderness of others in the far North.

While holding that top working is advantageous, the following
authors consider that the top is not made hardier by a hardy stock.

Budd (12) of Iowa says that there is no proof that a tree
which is liable to injury in Iowa can be made hardier by grafting
it on a hardier intermediate stock, but that top working is of

advantage in more than one way.

Lathrop (45) in Iowa, after 50 years of experience in
top working in his orchard, declares that top working will not
make truLy tender varieties hardy, and gives as an example a
variety killed back to the stock which remained perfect.

To the opinion of Knight (44), Lindley (46), Budd (12),
Lathrop (45), holding that the stock does not affect the hardi-
ness of the top,we might add the opinion of Hovey (41) of
Massachusetts, who said: "If trees could be made hardier by
grafting on hardy stocks, that would be a very important point;
but the idea of acclimation by this means is utopian."

Effect of cion on hardiness of stock

The influence of the cion on the stock has always received
less attention than the reverse effect of stock on cion. One
may suppose that the lack of interest in the stock for itself
explains, at least in part, this fact. The stock gets its
importance in fruit trees and vines only in so far as it helps
the top to produce good fruits in quantity and year after year.
Nevertheless few instances of the action of cion on hardiness of
stock have been recorded.

It is interesting to note that Budd (12), who held that the
top is not made hardier upon a hardy stock, found that a tender
cion affects the hardiness of the stock and states (15): "With
the one thousand or more Gros Pommier stocks used, the great lesson
is that the relative hardiness of the variety used in top working
affected the hardiness of the stock."

With roses, Carriere (16) reports an interesting experience

_ 13 _

in France. In one field out of many thousand roses of different
sorts, only three varieties were not winter killed. Not a single
individual of these three varieties was injured either in the
stock or the top. Of the other varieties, except for a few rare
individuals, they were completely killed and their stock too.

Ward (65),following the severe winter of 1890-91 in France,
showed that hardy stocks top worked with cions of tender varieties,
such as the tea and Bourbon roses, were killed; and in no instance
were such top worked stocks as hardy as the ungrafted hardy types.

Conclusions

 

In the light of the information available at the end of the
last century, the following conclusions seem to be justified, in
an attempt to reconcile the different opinions.

A hardy stock may increase the hardiness of the cion, at
least in certain cases. The hardy stock, however, does not appear
to transfer a part of its own hardiness as a specific quality of
its own, but affects the hardiness of the cion indirectly by
affecting its habit of growth, that is to say, by increasing the
vigor of the top in certain cases, or inducing an earlier maturity
in varieties which on their own roots are liable to grow too late
in the season. On the other hand, while scarcely noticed, the
stock may be increased or decreased in hardiness, at least in
certain cases, by a more or else less hardy top.

Before ending this review of literature of the last century,
it is interesting to note what Bailey (2) wrote of the reciprocal

influence of stock and cion in the 1900 edition of his "Cyclopedia

- 14 -

of Horticulture": "A fourth general office of grafting is

to adapt plants to adverse soil or climates..... The practice
in Russia of working the apple on roots of Siberian Crab is an
example of an effort to make a plant better able to withstand
a very severe climate.

"In common practice, the effect of the stock on the cion is
rather more a mechanical or physical one than physiological or
chemical. The influences are very largely those which are
associated with greater or less growth, as a rule each part of
a combined plant the stock and the cion maintain its individuality.
There are certain cases, however, in which the cion seems to
partake of the nature of the stock; and others in which the stock
partakes of the nature of the .cion."

Review of Literature From 1900

The end of the first decade of the 20th Century marked the
beginning of a new trend in horticultural research in the United
States. Its characteristics have become defined as the employment
of laboratory techniques, the use of statistical methods for
experimental planning and the analysis of data, and thirdly, a
cooperative outlook with reSpect to some of the other sciences,
particularly Botany, Chemistry, Soils and Climatology. The result,
thus far, has been a measure of progress towards the more fundamental
solution of certain major problems in Horticulture that was impossible
in the preceding century, with its narrower range of scientific
perspective and equipment.

With the help of new discoveries, better methods, new tech-

niques and greater cooperation, and in the light of the evidence

-15-

accumulated today, the conclusions drawn at the end of the 19th
Century could be changed or at least modified. However, before
considering the present ideas on the reciprocal influence of
stock and cion on hardiness, it is interesting to note what has
been in the last four decades the opinion on the practicability
of top working or double working as a means of growing less hardy
varieties farther North than their normal limit.

Double working in relation to winter injury

We already have seen, in the first Section, that topworking
or double working on hardy stock is not a new practice in the
orchard or the nursery. As it is understood that eXperiences in
one part of the country can be applied to another part only after
careful trials have been carried out, the idea on the practicability
and value of growing otherwise tender varieties on hardy stock will
be considered here with respect to the different sections of the
country.

In Eastern Canada, where hardiness in fruit trees is of the
highest importance, Macoun (49) reports: "We have done more or
less top grafting here for the past 17 years. I have been
interested in it merely from the standpoint of increasing the
hardiness of trees which grown as standard trees were not satis-
factory. After trying a great many varieties, about 90, I found
that the stock did not make the graft sufficiently hardy to with-
stand severe winters, so I have come to the conclusion that as
far as increasing hardiness is concerned, while top grafting may

make some difference, there is not enough to warrant this method."

-16..

About 25 years later, conversely to fiacoun (49), Blair (4)
does not hesitate to declare that the method of building a
hardy framework by double working has been too long overlooked
by fruit growers of Canada. He goes as far as to say that
this practice is of as great or greater importance than the
question of varieties. Blair made the above assertions after
an extensive survey on the damage caused by winter injury to
fruit trees in Eastern Canada. He also believes that it would
pay, in the long run, to plant only trees with hardy framework.
The procedure for building such a tree is given in detail: Only
seed of hardy Russian varieties are used; the varieties Antonovka,
Anis or Charlamoff are used as intermediate stock and the final
process is budding at about 18 inches on the main scaffold branches
with fairLy hardy standard varieties.

From Eastern Canada, crossing to the Northeastern States, we
find Potter (57) in New Hampshire who admits that much of the
trunk and crotch injuries can be avoided by t0p working certain
tender varieties on trees of very hardy sorts. Potter also con-
siders that the procedure "involves considerable expense and
greatly delays profitable production in the orchard." Unlike
Blair (4), however, he does not go as far as to recommend that
practice.

In a recent bulletin MacDaniels(48) gives preventive and
remedial methods for injuries to fruit trees in the orchards of
New York, but he does not include top working or double working
on hardy framework.

Blake (6) in New Jersey says that it would be desirable to

_ 17 -

have varieties of apple like Cravenstein, Tompkins King, Grimes
and Baldwin propagated on a late starting stock such as Northern
Spy forming at least a few inches of the trunk.

After the severe winter of 1955-56 an extensive survey on
winter injuries was made in Ohio. Havis and Lewis (38), like
Selby (60) 20 years earlier, found promising, for Ohio, the
method of top working on hardy framework. As, at that time, only
few orchards were top worked on such hardy stock as Hibernal, Haas
and Virginia Crab, they are not as yet able to give definite
recommendations.

Bradford and Cardinell (7) in Michigan are very explicit:
"There can be but little doubt that many orchards which have long
ceased to be profitable or have disappeared would still be pro-
ductive had they been composed of double worked trees." Rhode
Island Greening, Grimes Golden, King, Hubbardston, Cravenstein
and Stayman Winesap should be double worked, they say. As to
the stocks to work on the recommendations are given with reserva-
tions: Duchess and Hibernal "should support such varieties as
Vagener and Grimes Golden" but they hesitate to recommend them for
"free growers like Greening" stating that probably Fameuse would
do better. Tolman Sweet and Astrachan, on account of their
susceptibility to fire blight, are disqualified as hardy stocks.

In Indiana flcClintock (54) found Virginia Crab most promising
as a hardy stock, especially for Grimes Golden and Ben Davis.
Delicious proved to be too tender to be used as an intermediate

stock.

_ 18 _

Much work has been done in Iowa to investigate the possible
advantages of double working or top working in the apple orchard.
Holland (40) suggests a more extensive use of top working "to make
certain varieties better able to withstand unfavorable climate." He
reports that Jonathan, Grimes Golden and Delicious top grafted on
Hibernal and Virginia Crab are very successful "in Delaware and Clayton
Counties" considerably North of their usual limit.

Maney and Plagge (50) write: "In Iowa and most other states of
the Upper Mississippi Valley as well as Canada, where winter injury
is the limiting factor of successful orcharding, topworking on hardy
stocks is practical as a method for increasing the hardiness of the
best commercial varieties like Jonathan, Grimes and Delicious."

To show the beneficial effect of a hardy intermediate stock, they
give the following table:
Table II. - Record of Topworked Apple Trees in W. R. Campbell Orchard

Woodbine, Iowa. Orchard Planted 1895-94.

 

 

Trees alive Trees alive rPercentage of
Variety and Stock 1914 1954 trees alive
1954
Grimes on French Crab 72 5 4.0
Grimes on Virginia Crab 22 16 72.0
Grimes on Haas 155 52 58.0
Grimes on Sheriff 9 7 77.0
Gano on French Crab 84 5 5.5
Gano on Sheriff 57 26 70.0
Sheriff on French Crab 108 66 61.0
Jonathan on French Crab 115 50 26.0
Jonathan on Virginia Crab 15 7 54.0
Jonathan on Haas 44 56 82.0
Jonathan on Sheriff 2 2 100.0

 

 

 

 

_ 19 -

These records show clearly that the length of life of the trees of the
several varieties used has been increased by the three hardy stocks
used, namely, Virginia Crab, Haas and Sheriff.

Maney (51)again reports of 6-year-old trees of Jonathan and
Turley on French Crab alternating with double worked on Hibernal. After
the severe winter of 1955—56 he found the topworked trees "outstanding
in their freedom from winter injury." Understanding, "the fact that a
certain stock may be ideal for one variety is no indication that it
might do well with another", Maney (52) made a survey to secure some
information as to the compatibility of variety and stock combinations
for double working. For 45 varieties of apples he gives a "list of
stocks used successfully in top working."

The increasing interest in top working for hardiness lead the
Iowa Station to issue a bulletin entitled "Top Working on Hardy Stocks
to Produce Long-Lived Apple Orchards". A procedure is given to form
trees with hardy framework.

In Missouri Talbert (65) informs us that some top working is
done on Minkler, Arkansas, Hibernal, Virginia Crab and others to
replace the weak crotch structure and avoid the crown troubles of Grimes
and the standard varieties, but not so much for the hardiness of the
same parts.

In Wisconsin, Minnesota and the Dakotas, many of the semi-hardy
but desirable varieties are recommended only as top worked trees on
hardy intermediate stocks as Hibernal and Virginia Crab.

In the Pacific Northwest, the search for the best stocks for double
working is also going on. In Oregon at the Hood River Station the

following varieties have been found promising as intermediate stocks:

- 20 -

Astrachan, Arkansas, Cortland, Scott Winter, Hibernal, Antonovka,
Oskakoff and also McIntosh (17). It is worth noting that Virginia
Crab has not proven hardy enough (8).

The use of double working in an attempt to overcome some
winter injuries has also received some attention in central Europe.
In Poland, Filewicz (29) stresses the value of double working.
Antonovka is the stock extensively used an an intermediate. The
recommendations of Filewicz differ from all that we have noted so far
in one point — one or two braches of the hardy intermediate stock are
allowed to grow and he claims that these increase the resistance of
the tender variety: "The trees .... on hardy trunks do not suffer
from frost, and because of the symbiosis of tender variety with a
hardy one they neither need bridge grafting nor invigorating."

It would seem interesting, before ending this chapter, to
have a summary of the work that is going on in Canada to find the best
adapted rootstocks and intermediate stocks to meet the requirements
of different regions. At Ottawa, Ontario, they are comparing the
single worked trees with double worked trees on hardy Russian varieties,
namely, Hibernal, Antonovka, Anis and Charlamoff. These are all propa—
gated on uniform hardy rootstock, "which is considered to be quite
homozygous." Finally these are worked over to McIntosh and Fameuse
by inserting buds 18 to 24 inches from the trunk on the main scaffold
limb. This experiment divided into six blocks is planned to permit
the use of the best methods of statistical analysis (5).

At Cap Rouge, Quebec, a similar experiment is going on. The
commercial varieties, McIntosh, Lawfam and Lobo, are top grafted on

Antonovka, Hibernal, Charlamoff and Patten Greening as intermediate

_ 21 _

stocks. The rootstock is Anis. The experiment is divided into six
blocks also (59).

In Western Canada, some work is also being carried on along the
same line at Sommerland, B. C.

From this inquiry into the practice of double working on hardy
intermediate stocks, one sees that new interest has recently arisen
about the practical advantages in the method to grow hardier, healthier
and longer lived trees. This beneficial effect is expected to be
accomplished not so much by the influence of the stock on the hardiness
of the top, as to fit a top with a hardier trunk or hardier crotches
and render the tree more able to struggle successfully against cold
injuries. In the next chapter we shall see if the top, in the grafted
tree, partakes of the hardiness of the stock or may be influenced in
its hardiness some other way by grafting.

Hardiness and reciprocal influence of stock and cion

It is a general belief that the use of a hardy stock is an
effective means of making a tree better able to withstand cold weather.
The hardy stock may be beneficial merely by substitution of tender
parts with hardier ones, by the building up of a hardier root, trunk
or crotches. But the question arises - does the hardier stock
exercise a beneficial influence on the hardiness of the cion tissue of
the variety grafted upon it? We already have noted in the first
Section a few observations on this point; we shall note a few more
that have more recently been reported.

At Ottawa, Canada, 90 varieties of apples were top grafted on
hardy stocks to see if they could be made hardy, but practically all

were killed back to the stock. The cions were six years old or less.

-22..

Macoun (49) concluded that if the top varieties are made hardier it
is not enough to enable them to withstand very severe winters. It
may be said here that examples by thousands could be given where
tender grafted varieties have been killed back to the stock. These
negative results, though, should not overshadow the few controlled
cases where the cion itself may have been rendered more hardy by
grafting on a hardy stock which did influence its grafted associate.

It is interesting to quote the opinion of Culley (56) who
declares: "Without doubt both hardiness and stronger growth are trans—
mitted to an extent, from stocks having those characteristics. But
I have yet to note that these are in any sense permanently transferred
to the top or that the fruit is affected other than environment would
account for."

With Macoun (49) tender tops were not made, by the stock, hardy
enough to endure the test winter of 1905-04. It is supposable, though,
that some tops may have been slightly hardier but not enough to make
them endure such a test winter; so it may be said with Hedrick (59):
"It would be too much to say that hardiness as an inherent quality is
transmitted from stock to cion, but it is very certain that increase
in vigor imparted by some stocks gives better hardiness to grafted
plants. In the case of late growing apples worked on Hibernal or
Oldenberg stock greater hardiness results because the cion matures
earlier than it would upon its own roots and is therefore better able
to withstand the winter. Again,.slight obstructions to the sap flow
imposed more or less by union of different tissues of stock and cion
may cause the cion to ripen earlier and this bring about greater

hardiness."

_ 25 _

Dorsey (24) in 1918, using the degree of browning of wood as
an index of winter injury, undertook one of the first systematic
laboratory studies of the reciprocal influence of stock and cion on
hardiness. The degree of injury was determined by cutting, into
selected limbs of one to one—and~a—half inches in diameter, three to
five annular rings deep with a sharp knife or hatchet. Dorsey
considered that the browning, varying with the severity of the winter
and with the hardiness of a variety, was "a most sensible index of
the winter injury." The conclusions he arrived at were as follows:
"The hardiness of the cion is independent of that of the stock and
if a hardy stock does have an influence upon the hardiness of the
cion, it is not sufficient to prevent it from being injured by low
temperatures." Dorsey states elsewhere (25): "Fundamentally the
stock does not increase the hardiness of the cion except in so far
as maturity and nutrition may have a bearing upon hardiness."

Working on the same line Carrick (15) undertook an experiment
to find out whether the cions of varieties of different hardiness did
not influence the hardiness of the stock roots grafted under them.
Six hundred forty piece-root grafts of four different varieties were
made on stocks of long rooted American seedlings cut into four parts.
Each variety was grafted on each of the four cuts. As an index of
injury in the roots, the percentage of cells killed in the cambium
phloem and Cortex region was taken. No "constant nor considerable
differences in hardiness" were noted in the hardiness of the one—year
roots of the stock grafted under the four different varieties. It was
also shown that there is no significant variation in the hardiness of

the grafted and ungrafted seedling stocks.

- 24 -

Gardner, Bradford and Hooker, in their book, "The Fundamentals
of Fruit Production", write: ".....that hardiness of the stock
increases the hardiness of the cion is not shown conclusively by any
evidence available. It is conceivable that an early maturing stock
might influence the top slightly in the same direction but any
influence of this character is comparatively insignificant." (55).

In another chapter, it is said also: "It is conceivable that a
stock may in itself be hardy but through the congeniality of the
graft it may actually diminish the hardiness of the cion." (54).

Potter (56),in accordance with results reported by Carrick (15),
cited above, concluded from his own experiments that cions of varieties
of different hardiness do not influence the hardiness of the stock
roots which are grafted under them. Garrick had worked with one-year-
old grafts while Potter reached the same conclusions with threefiyear—
old grafts. Potter states that apparently no compounds which influence
hardiness are translocated from the stock to the cion. It should be
pointed out here that neither Potter nor Garrick worked with clonal
rootstocks. The variability due to the different genetical make-up
of seedling rootstocks may possibly be responsible, at least in part,
for their failure to find an influence which, if it exists, must be
of small magnitude.

The observations of Filewicz (28), as we shall see, would seem to
show that the influence of the two or more components of a grafted tree,
on one another, is dependent on the age of the union or unions. Filewicz
states that tender varieties could be made more resistant by top graft—
ing with hardier varieties while hardiness could also be diminished by

tender top varieties. His findings are based on extensive observations

-25..

in the orchards for many years and more especially after the unusually
severe winter of 1928-29 which caused so much damage to fruit trees

in Central Europe. He sums up as follows the observations he made on
Conlon's Reinette, a variety grown there for its fruits as well as an
intermediate stock: "1. when not top grafted a large percentage died
of frost; 2. after cutting it offers little resistance against frost
for many years. All trees grafted since 1925 with varieties of medium
or little resistance died after the winter of 1928-29; 3. grafted with
a very resistant variety (Antonovka) in 1924 the trees became resistant
in five years, and 4. grafted with a fairly resistant variety (Broiken)
only after ten years."

It has been shown above that Garrick (15) as well as Potter (56)
failed to find any consistent augmentation of hardiness, in the root-
stocks, attributable to the cion grafted on. They were working with
one-year and threeayear-old grafted material, respectively. These
were relatively short unions when we consider that with Filewicz (28)
it took five years for a very resistant variety to make its intermediate
stock hardy and as long as 10 years for a fairly resistant variety to
accomplish the same. One many infer, though, that an intermediate
stock can possibly react in a different way, as a rootstock does, and
conceivably can be slower or faster to respond to the action of the
cion.

Filewicz (29) again claims that a tender top is made more hardy if
a few grafts of a hardy variety are grown in it, or if one or two branches
of the hardy intermediate stock are allowed to bear foliage. Would these
observations corroborate the views of Burbidge (14) who wrote in the last

century: "Do we not rob the stock of a deal of its power to ameliorate

_ 25 _

the scion when we denude it of all its own leaves?" I should think
that this question, of the effect of a not completely defoliated stock
as compared to a completely defoliated one, should receive more
attention than has been devoted to it so far.

The hard test winter of 1955-54 gave to Blair (4) a very good
opportunity to analyze statistically winter data. Thirteen different
varieties of apples grafted on six different rootstocks were growing
in six randomized blocks. The unions were four years old. The
analysis of variance of the injury measured after a given system of
pointing was done. Not even in a single instance was a significant
difference between any of the rootstocks as imparting hardiness to
any double worked variety found.

The examination of the literature so far would seem to point out
the need of a practical and sensible test to be applied to the solution
of the problem. Recently, the exosmosis method of measuring cold
resistance devised by Dexter (21) (22) (25), and tested for apple tissues
by Swingle (62), was tried on the problem by Stuart (61). In order to
avoid variability in seedlings due to different genetical make—up,
clonal rootstocks were used. Contrary to Potter (56) and Garrick (15),
Stuart found that the cion can appreciably affect the hardiness of the
rootstock, but it is worth noting that the direction of this influence
could not be predicted from the hardiness of the cion variety. As to
the effect of stock on the hardiness of the cion, the results were
different: no significant appreciable difference was found. The
material used in this experiment was only one growing—season old after

budding.

_ 27 _

Conclusion

After this review of literature dealing with the subject, one
sees that the reciprocal influence of stock and cion on hardiness
is not a problem that has ceased to be controversial. Little conclu-
sive information is as yet available and the problem stays an open
one for investigation and research. Probably very sensitive and
accurate method of testing hardiness is necessary before there can
be a closer approach to its solution. Parenthetically, the method
based on electrical conductivity used by Stuart (61) would seem to
be promising. Also in an endeavor to minimize the difference
necessary to be significant, any eXperiment on the subject should be
previously planned to permit the use of the best and more refined
methods of statistical analysis. Finally, variation in the material
should be controlled as much as feasible, so clonal rootstocks should
be used, even in an experiment to test the influence of the intermediate

stock on the cion.

(5)
(6)

(7)

(8)
(9)

(10)
(ll)
((12)
(15)

(14),

(15)

(16)

(17)

(18)

(19)

- 28 -
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