1062 
fruitful. The present trend of science is 
against such a possibility. Hven were it 
possible, there are a number of practical 
drawbacks. 
Thus, from tree generation to tree gen- 
eration constitutes a period of time too 
long for most men to bend their efforts, 
especially with that clear conception of 
exactly what is wanted that is required in 
the intricate problem of plant selection. 
The variations at best are but slight and 
hundreds of trees would have to be ex- 
amined to find one or two from which to 
start a new race. One would have to 
make sure, too, that the selected plants 
would not fall behind their fellows in 
other characters. The variations men- 
tioned are almost certainly the result of 
environment and are not passed on from 
one tree generation to another so that, 
even were the obstacles not so great in 
practicing selection that few men would 
be able, or would take the pains to sur- 
mount them, heredity could not be count- 
ed as a factor in causing the formation 
of buds. 
Biennial Bearing 
Another phase of the subject of fruit- 
bud control is the biennial bearing habit 
of some varieties of the several fruits 
and especially of the apple. So marked is 
this habit in apples that we can ascribe 
it as one of the characters of that fruit. 
A good deal of attention has been given 
by orchardists and experimenters to bi- 
ennial bearing in apples, but as yet no 
one has been able greatly to change na- 
ture’s way. It is maintained by some 
that the biennial bearing habit is due to 
the heavy crop which exhausts the tree’s 
energies and that a light crop follows be- 
cause of such exhaustion. This can be 
but partly true; for all can call to mind 
two, three, or four heavy crops of some 
varieties after which the trees settle down 
to bearing in alternate years. 
Thinning 
Nor does thinning, often proposed as a 
remedy for overbearing, prove of much 
value. Pruning seems to alter the condi- 
tion but little. We have on record sev- 
eral experiments in which blossoms were 
stripped from the trees during the bear- 
ENCYCLOPEDIA OF PRACTICAL HORTICULTURE 
ing year to cause the setting of fruit 
during the off year. The trees so treat- 
ed usually bear some fruit the off year 
but seldom a satisfactory crop. Nor is 
the matter one of food supply. Orchards 
amply supplied with food are not always 
annual bearers. Peculiarities of the sea- 
son have something to do with alternate 
bearing but do not wholly account for it 
Eliminating all the above conditions— 
admitting, however, that all have some in- 
fluence of the bearing habit—we must 
conclude that the biennial bearing habit 
of apples is a peculiarity of the species. 
Good cultivation, an ample supply of food 
at all times, careful attention to pruning 
and training, proper control of rests and 
systematic thinning, are all means which 
can be used to some extent to circumvent 
nature. 
Development of Fruit Buds 
Leaving now the formation of fruit 
buds, let us see what can be done to con- 
trol the development of fruit buds. 
Blooming, the prelude of fruiting, had 
little significance to the fruit grower un- 
til the discovery was made that many 
varieties of several fruits were unable to 
fertilize themselves and that failures of 
fruit crops were often due to the plant- 
ing of infertile varieties. The knowledge 
obtained by experimenters in this field 
has to some degree modified the planting 
of all orchard fruits. Pollination and 
fertilization are events which take place 
in blossoms that must be reckoned with 
by fruit growers. 
Pollination 
It is necessary to distinguish between 
pollination and fertilization, terms sup- 
posed by many to have the same mean- 
ing. Pollination is the dusting of the 
stigma, the female organ of a flower, with 
pollen, the male element. Fertilization 
is the process in which the male cell 
unites with the female cell. Fertilization 
takes place only after pollination, but a 
flower may, of course, be pollinated and 
fertilization not take place, a fact always 
to be remembered. Fruits set and de- 
velop, for most part, only after fertiliza- 
tion. The young fruits when first form- 
ed have but a slight hold upon life. Un- 
