The Garden Magazine, August, 1921 
373 
in the germ cells (which, 
in a plant, are known as 
the ovules or, in young 
seeds, as the female germ 
cells; and the pollen 
grains as the male germ 
cells.) 
A male and a female 
germ cell must unite into 
one cell, the process of 
fertilization, to produce 
a viable seed which will 
give rise to a .new plant. 
A “recessive” character 
must be carried or shown 
by both parents in 
order that such a charac- 
ter can become visible in 
their offspring. On the 
other hand, a“dominant” 
character is one which 
will show in the offspring 
whether it is a character 
of only one or of both the 
parents. A recessive 
character is thus pre- 
vented from appearing 
by the presence of the 
dominant character, 
whereas it could develop 
if the dominant charac- 
ter were absent. Green 
color in a Corn seedling 
is a dominant character. 
Purely white seedlings 
always die as soon as 
they have used all the 
food stored in the grain 
from which they grew. 
This green coloring mat- 
ter in the plant (the 
chlorophyl) is the chem- 
ical machine for the 
manufacture of starch 
from the carbon dioxide 
of the air. Without the 
starch the plant cannot 
live and in this way the lack of green in the Corn seedling 
causes its death. 
A plant which receives the recessive character, white, from 
one parent and the dominant character, green, from the other 
will be green and grow in a normal way. It will, however, be a 
hybrid and able from self-fertilized seed to produce green and 
white seedlings in the proportion of 3 green to 1 white. While 
this is of most interest as a natural phenomenon it also has a 
certain practical bearing on crop production, inasmuch as 
Corn which carries this recessive factor will not produce as good 
a field stand as Corn free from it, because every white stalk of 
Corn means a vacant place in the field. Ordinarily, the per- 
centage of white seedlings in a field is so low that it is not worth 
while to try to eradicate the hereditary factor from the seed. 
If, however, a farmer or gardener should find very many of these 
white seedlings and should care to take measures to eliminate 
this from his seed stock it can be done in the following way. 
AS STATED above, the green plants, hybrid for the white 
/Y condition, produce seedlings in the ratio of 3 green to 1 
white. All the white plants die as seedlings, leaving only the 
green ones to produce seed, and it is therefore evident that some 
of these green stalks are able to produce white plants. It has 
been found by experiments that about two thirds of these green 
plants when self-fertil- 
ized will again produce 
both green and white 
seedlings in the same 
ratio as before and that 
one third of the seedlings 
will produce only green 
seedlings. By looking at 
the Corn, both growing 
and after gathering, no 
difference between the 
pure green and the 
hybrid green plants can 
be discovered. 
The gardener must 
select certain plants to 
produce his seed ears 
and cover both tassels 
and shoots before the 
pollen ripens and before 
the silks appear on the 
shoots. The bags to be 
put over the shoots to 
protect the silks should 
have the bottom opened 
by cutting off a small 
strip from the end of the 
folded bag thus making 
a paper cylinder. Fold 
about one inch of the 
cut portion over once 
and hold in place with 
an ordinary paper clip. 
Several days later, when 
the silks have appeared, 
remove the clip from the 
folded end of the bag, 
open it, then cut off the 
bagged tassel, cut a hole 
in the corner of the bag 
and shake the pollen over 
the silks. Close up the 
top of the bag on the ear 
and replace the clip. 
This same method may 
be used in cross hybrid- 
izing Corn except that 
the pollen must be taken from another plant. 
About 100 ears self-pollinated in this way will supply enough 
seed for the garden or truck farmer. Before the spring planting 
time, plant in boxes 30 grains from each of the self-pollinated 
ears, numbering ears and rows of planted grains to correspond. 
After the Corn comes up, if any row of the 30 grains produces 
any white seedlings, throw out of the seed collection the ear from 
which these seeds came. It would be fairly safe to say that the 
ears which produced no white seedlings were free from this 
character and could be used for planting the truck or garden crop 
and would perhaps produce a higher percentageof mature plants. 
I NBREEDING with plants and animals has had its ins 
and outs, its ups and downs. There is perhaps no other 
thing in nature about which there has been so much con- 
jecture, superstition, and ignorance. Who has not heard 
tales of the dire calamities following the mating of rela- 
tives? Have we not had laws from the days of antiquity to 
discourage such a practice in the human race? During the last 
decade the geneticists have done much to clear up the situation; 
and especially has the work on naturally cross and self-fertilized 
plants contributed to this enlightenment. 
When naturally cross-fertilized plants — such as Corn, certain 
plants of the Sunflower family, and most of our fruits — are 
FREAK PRODUCTS OF SELF-FERTILIZATION 
The "corrupt fruit” of inbreeding. Such abnormal and monstrous plants 
as these have helped to give to the practice of inbreeding the bad repu- 
tation which it commonly bears. These are hereditary, but being reces- 
sive characters seldom appear except when the plants are inbred by forced 
self-fertilization. The stems of the upper plants are flat and ribbon like; 
those of the lower plants are round but grow in a screw-like spiral 
