Pedigreed Grape Vines





Many viticulturists, in common with orchardists, believe that their

plants should be propagated only from parents which have good

characters, that is, are vigorous, healthy, productive, and bear fruit

of large size, perfect form, good color and good quality. They

believe, in short, that varieties can be improved by bud selection.

There is, however, but little in either theory or fact to

substantiate the belief of those who say that varieties once

established can be improved; or, on the other hand, that they

degenerate. Present knowledge and experience indicate that heredity is

all but complete in varieties propagated from parts of plants. The

multitude of grapes in any variety, all from one seed, are

morphologically one individual. A few kinds of grapes go back to

Christ's time, and these seem to agree almost perfectly with the

descriptions of them made by Roman writers 2000 years ago. How, then,

can the differences between vines of a variety in every vineyard in

the land be explained?



Ample explanation is found in "nurture" to account for the variation

in vines without involving a change in "Nature." Soil, sunlight,

moisture, insects, disease, plant-food, and the stock in the case of

grafted vines, give every vine a distinct environment and hence a

distinct individuality of its own. Peculiarities in a vine appear and

disappear with the individual. A variety can be changed temporarily by

its environment, but remove the incidental forces and it snaps back

into its same old self.



Heredity is not quite complete in the grape, however; for, now and

then, sports or mutations appear which are permanent and, if

sufficiently different, become a strain of the parent variety or

possibly a new variety. There are several such sports of the Concord

under cultivation. The grape-grower can tell these sports from the

modifications brought about by environment only by propagation. If a

variation is transmitted unchanged through successive generations of

the grape, as occasionally happens, it may be looked on as a new form.

"Pedigreed" vines, then, should be subject to a test of several

generations in an experimental vineyard before the grape-grower pays

the price demanded for the supposed improvement.












TTTTLE STOCKS AND RESISTANT VINES





Phylloxera, a tiny root-louse, made its appearance in France in 1861



and began multiplying with a fury unparalleled in the insect world. By

1874, the pest had become so widespread in Europe that it threatened

the very existence of the great vineyard industry of that continent.

All attempts to bring the pest under control failed, although the

French government offered a reward of 300,000 francs for a

satisfactory remedy. Numerous methods of treating the soil to check

the ravages of the insect were tried, also, but none was efficacious.

Finally, it dawned on European vineyardists that phylloxera is not a

scourge in America, its habitat, and that European vineyards might be

saved by grafting Vinifera vines on the roots of immune American

grapes. At once the reconstruction of vineyards in Europe was begun by

grafting the grapes on phylloxera-resistant roots. Meanwhile,

consternation spread to California when it was discovered that

phylloxera was running riot in some of the vineyards of the Pacific

slope; however, with the knowledge derived from viticulturists in

Europe, they too began reconstructing vineyards on immune roots,

without the same success as the Europeans, it is true, but with such

measure of success that it soon became the approved method of growing

grapes in this great region.



Through the use of resistant stocks, phylloxera is now defied in

Vinifera regions. Millions of American stocks are annually struck at

home, in Europe and wherever Vinifera grapes are grown, to be

top-worked with varieties susceptible to phylloxera. Seldom has

mastery over a pest been so complete; but, to triumph over the tiny

insect, the industry has had to be revolutionized. Resistant stocks,

in their turn, brought innumerable new problems, many of which are

still unsolved. Investigations and experiences in rehabilitating

vineyards have been carried on for forty years, the results set forth

in books and bulletins and yet there are many problems to be solved.

The grape-grower in regions infested with phylloxera is always under

the necessity of taking advantage of the latest demonstration of

practices in the use of resistant stocks. These practices are best

studied in the experiments of state experiment stations and the United

States Department of Agriculture, and in the vineyards of leading

grape-growers, since even those most needing elucidation can be but

briefly discussed in the following paragraphs.



The wild vines of a species are always seedlings and are hence

exceedingly variable. The first vineyards of resistant stocks were

vines grafted on stocks of wild vines, and the results were very

unsatisfactory; for, naturally, there was divergence in many

characters and especially in the vigor of the vines. Also, there was

difficulty in grafting, since some wild vines are stout and others

slender; some bear grafts well, while others do not. It soon became

apparent that to succeed, varieties must be selected from the

different species for vineyard work. The great task of the

experimenter and grape-grower, therefore, has been to select varieties

of the several species sufficiently resistant, vigorous and otherwise

possessed of characters fitting them to become good stocks. Out of

vast numbers tested, a few are now generally recognized as best for

the several groups of Vinifera grapes and the several distinct regions

in which these grapes are grown.



Resistant species and varieties.



The reconstruction of phylloxera-ridden vineyards by the use of

resistant stocks is possible only because some species and varieties

are, as has been said, more resistant to the root-louse than others.

All degrees of resistance exist, as would be suspected, from immunity

to great susceptibility. It is obvious that the foundation of the art

of growing resistant vineyards is exact knowledge of the immunities

and susceptibilities of the many varieties and species of grapes. From

the first use of resistant vines, experimenters everywhere have set

themselves at work to determine not only what the most resistant vines

are, but what the causes and conditions of immunity. In spite of a

wealth of empirical discoveries as to what grapes can best resist the

root-louse, causes and most of the conditions of immunity are still

little understood. Definite, useful knowledge, so far, goes little

further than the establishment of lists of species and varieties, the

latter subject to change, that are most useful in setting resistant

vineyards.



Phylloxera does little damage to species of Vitis native to the same

general region in which the pest has its habitat, but nevertheless

there are some differences in resistance in American grapes. Munson,

one of the best American authorities on the resistance of species to

phylloxera, says:[7] "Rotundifolia is entirely immune, then Rupestris,

Vulpina, Cinerea, Berlandieri, Champini, Candicans, Doaniana,

AEstivalis and Lincecumii are so high in resistance as to be

practically uninjured, though they may be attacked, while Labrusca is

low in resistance and is much weakened in clay soils, if infested, and

Vinifera is entirely non-resistant." Some of these species are hard to

propagate and difficult to suit in soil and climate so that but two of

them are much used for resistant stocks. The two most used are

Rupestris and Vulpina (Riparia), of both of which there are varieties

which give satisfaction. Bioletti, a leading authority on resistant

stocks in California, says:[8]



"Varieties of resistant stocks which will in all probability be used

in California are Rupestris St. George (du Lot), Riparia x Rupestris

3306, Riparia x Rupestris 3309, Riparia Solonis 1616, Mourvedre x

Rupestris 1202, Aramon x Rupestris 2, Riparia gloire, and Riparia

grande glabre. These are all varieties which have given excellent

varieties for years in Europe, and have all been tested successfully

in California. Among them are varieties suitable for nearly all the

vineyard soils of California, with perhaps the exception of some of

the heavier clays.



"The only one of these varieties which has been planted extensively in

California is the Rupestris St. George. There can be little doubt,

however, that it will fail to give satisfaction in many soils, and

though we may not find something better for all our soils it is

probable that we will repeat the experience of Southern France and

find that in most soils there is some other variety that gives better

results. Without attempting to describe these varieties, but to give

some idea of their merits and defects and of the soils most suited to

each, the following indications are given, based principally on the

opinions of L. Ravaz and Prosper Gervais, and on a still limited

experience in California:



"The Rupestris St. George is remarkably vigorous and grows very large,

supporting the graft well even without stakes. It roots easily and

makes excellent unions with most vinifera varieties. It is well suited

to deep soils where its roots can penetrate. Its defects are that it

is very subject to root-rot, especially in moist soils; it suckers

badly and it suffers from drought in shallow soils. Its great vigor

produces coulure with some varieties and often necessitates long

pruning.



"In moist or wet soils 1616 or 3306 had given better results in France

and gives indications of doing equally well here. In drier soils 3309

will probably be found preferable.



"Aramon Rupestris No. 2 is suited to the same soils as Rupestris St.

George, and does particularly well in extremely gravelly soils. It

has some of the defects of the St. George and is moreover more

difficult to graft, and its only advantage in California is that it is

rather less susceptible to root-rot.



"There are no better resistant stocks than Riparia gloire and Riparia

grande glabre, wherever they are put in soils that suit them. They do

well, however, only in deep, rich, alluvial soils which are neither

too wet nor too dry. Their grafts are the most productive of all, and

ripen their grapes from one to two weeks earlier than the grafts on

St. George. Their principal defect is that they are very particular as

to the soil, and they never grow quite as large as the cion. The

gloire is the most vigorous, and the difference of diameter is less

with this variety than with any other Riparia.



"The Mourvedre x Rupestris 1202 is extremely vigorous, roots and

grafts easily, and is well adapted to rich, sandy and moist soils. In

drier and poorer soils its resistance is perhaps not sufficient.



"The most promising varieties for general use at present seem to be

the two hybrids of Riparia and Rupestris, 3306 and 3309. They have

great resistance to the phylloxera, root and graft almost as easily as

St. George, and are quite sufficiently vigorous to support any variety

of vinifera. The former is more suited to the moister soils and

wherever there is danger of root-rot, and the latter to the drier

soils. In general, they are suited to a larger variety of soils and

condition than perhaps any other varieties.



"Riparia gloire should be planted only on rich, deep alluvial soil

containing an abundance of plant food and humus, what would be called

good garden land, such as river bank soil not liable to overflow.



"In most other soils Riparia x Rupestris 3306 is to be recommended,

except those that are rather dry, where 3309 is to be preferred, or

those which are very wet, where Solonis x Riparia 1616 is surer to

give good results."



The value of a species or variety for a resistant stock may be judged

somewhat by the visible effect of the phylloxera on the roots of the

vines. On susceptible species, the punctures of the insects rapidly

produce swellings which vary in size and number in accordance with

resistance of the species. Technically, the first swelling on the

young tender rootlets of the vine is called a nodosity. The presence

of a few nodosities on the root system does not indicate that a vine

is not a valuable resistant stock. When the nodosity begins to decay

and becomes of a cancerous nature, it is called a tuberosity. These

tuberosities decay more or less rapidly and deeply, and when they rot

deeply cause enfeeblement or death to the vine. Thus, on Vinifera

varieties the tuberosities are several times larger and decay sets in

much more quickly than on American species which show these

tuberosities. Ratings as to resistance of species are usually made

from the size and number of the tuberosities, though when these are

found producing a scab-like wound which scales off, there may be high

resisting power.



In order to convey with some degree of definiteness the power of

resistance to phylloxera, an arbitrary scale has been agreed on by

viticulturists. In this scale, maximum resistance is indicated by 20

and minimum by 0. Thus, the resisting power of a good Vulpina is put

as 19.5 and that of a poor Vinifera variety as 0.





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