SOUTHERN CULTIVATOR. 
181 
HOW TO INCREASE THE SIZE OF FRUIT. 
BY A. DUBREUIL. 
There are many processes by which the size of fruit 
may be increased, such as training, thinning, watering, 
pinchirrg, &c. The French cultivators excel in this de- 
partment of pomology ; and as there is unusual interest 
manifested in obtaining large and fine specimens, particu- 
larly for exhibition, we are pleased to present our readers 
with the following valuable information, detailing the 
principle operations for obtaining such results. The 
article is by A. Dubreuil, one of the most skillful French 
cultivators, translated from the Annales d' HorticuUure de 
Grand : 
1. Grafting the Trees on a weak species of Stock . — 
Fruits, like leaves, have the power of attracting the sap 
from the roots, and of transforming it into cambium, or 
organisable matter. But, contrary to that which takes 
place in the leaves, they employ all the cambium which 
they thus elaborate for their nourishmentt. If the stock 
on which the tree is worked is naturally possessed of 
great vigor, the tree will produce numerous long shoots, 
which will appropriate the greater portion of the sap, to 
the detriment of the fruits, which will, consequently, not 
attain a large size. They will, on the contrary, acquire 
a larger size if their absorptive power can counterbal- 
ance that of the shoots. It is for this reason, that, all 
other things being equal, the fruit of trees worked on the 
quince stock is larger than that from trees worked on the 
pear stock. The same thing takes place with regard to 
apple trees grafted on the Paradise, as compared with those 
on the Crab stock, 
2. Subjecting the Trees to a proper mode of Priming . — 
This operation when well performed, has the effect of de- 
priving the trees of a certain portion of their shoots 
Hence it follows that a great portion of sap which would 
have been absorbed by the p^rts cut off, goes to increase 
the size of the fruit. The object of summer pruning is 
likewise the complete or partial removal of a number of 
shoots by disbudding and pinching. These operations 
contribute to turn the sap to the benefit of the fruit ; and 
under like circumstances, the fruit of well-pruned trees is 
always larger than that from trees left unpruned. 
3. Operating so that the Bearing Shoots may be as short 
as possible, and in the immediode connection with the main 
branches . — If the mode of pruning adopted is such that 
the bearing shoots immediately proceed from the principal 
branches, the consequence is that the fruit, receiving the 
sap more directly from the roots, acquire a larger size. In 
fact, it is seen that fruit growing on the stem is always 
larger than that situated at the extremities of long, slender 
branches. 
4. Thinning the Fruits wheen too numerous . — The 
quantity of sap, disposable for the growth of the trees, 
does not increase in proportion to the fruit which it bears. 
It is, therefore, apparent that the more numerous the 
fruits, the less the amount which each receives. Hence 
the utility of thinning, in order that those retained may 
be better nourished and become larger. The proper time 
for performing this operation is when the fruits are fully 
set. 
5. Shortening the Principal Branches . — If the length 
of the principal branches is, to a certain extent diminished, 
by shortening them at the winter piuning, a result analo 
gous to that produced by ordinary pruning will follow; 
but the effect on the fruit is much more intense, becaui^e 
the action of the sap is confined within narrower limits 
It is, however, important to check in summer the vigor- 
ous shoots, ot which agieat number will be sure to make 
their appearance, otherwise they would absorb a large 
amount of sap, to the detriment of the fruit 
C). Supporting the Fruits so that their weight may not 
cause a strain upon the Footstalk . — The sap from the 
roots enters the fruit by means of vessels passing along 
the footstalk, and which ramify, to an infinite extent, 
throughout the cellular mass. Bulky fruits, such as 
pears and apples, soon attain such a weight that they ex- 
ert a strain on their footstalks, which, by tightening the 
woody fibres and vessels, tends to collapse them. The 
tissues of the stalk being thus composed, the passage of 
fluids is, to some extent, obstructed in that part. More- 
over, if fruits are attached to a branch having a more or 
less vertical direction, their gravity will cause a bending 
of the stalk, and will thus still further obstruct the pas- 
sage of the sap. Again, it often happens that the fruit 
does not make an equal growth on both sides of its lon- 
gitudinal axis, and a twisting of the stalk and strangling 
ofthe ves'^els take place, in consequence of which the 
circulation is partially intercepted. Now, if a support is 
placed beneath the fruit so as to prevent these effects on 
the stalk, it is nery evident that the sap will flow in much 
greater abundance into the fruit, which will then become 
larger. This is the reason why those fruits which acci- 
dentally rest on branches or trellises are always of greater 
size than the rest. 
7. Moderating the amount of Ecaporation from the 
Fruit.— \n order that fruits may swell, their epidermis, or 
skin, must be continually expanding, so as to make room 
for fresh tissues which are forming in the interior, and the 
new fluids that are accumulating there. If all the parts 
of fruit are directly exposed to the full force of the sun and 
the drying action of the air, it will lose bj' evaporation 
an amount of fluid nearly equal to that which it receives 
from the roots, and its growth will, therefore, be less rapid. 
On the other hand, the tissues nearest the outside will 
acquire a greater degree of firmness, and lose, to some de- 
gree, their elasticity ; they will offer more resistance to 
the expansion of the interior tissue, and will consequent- 
ly restrict the growth of the fruit. If, on. the contrary, 
the fruit is kept'in the shade, these influences will not 
affect it, and it will become larger. Indeed, this may be 
observed in the greater proportion of fruits covered by 
leaves as compared with those on the same tree, not so 
covered. It is necessary, however, in order that shading 
may not affect the quality of the fruit, to expose the latter 
when full grown to the direct action of the sun. To di- 
minished evaporation must attributed the considerable 
increase in size which always takes place in fruit intro- 
duced into bottles soon after it is set. The mouth of the 
bottle being closed after the proportion of branch with the 
young fruit is introduced, the latter is secluded from the 
drying action of the air, and is constantly surrounded with 
a moist, warm atmosphere, which keeps the epidermis 
pliable, and stimulates the growth of the tissues 
8. Moistening the Fruits v:ilh a solution of Iron {cop- 
peras ) — We have already stated that fruit has the pow- 
er of drawing towards it sap from the roots. If means 
can be found stimulating its vital energy, it will be per- 
ceived that it will absorb a greater amount of sap and at- 
attain a larger size. Now, M. Eusebe Gris has proved 
that a solution of sulphate of iron applied to the leaves has 
ihe effect of increasing their absorptive powers, and 
stimulating their cellular tissues ; and it was only reason- 
able to suppose that salt would produce the same effect on 
the fruit. This, indeed, has been ascertained by M. 
Arthur Gris, who has continued the interesting researches 
of his father. He has proved that melons, and various 
species of fruit trees, the leaves of which had been 
watered on several occasions with a weak solution of sul- 
phate of iron, yielded much larger fruits than those not so 
treated. One of my pupils repeated the same experiment 
in 1854 and 1855 on pear trees. He gave the first water- 
ing so soon as the fruits were fairly set, in the end of 
