THE NEW CRAFT OF MAKING PLANTS TO ORDER 
J. L. COLLINS 
Dept, of Genetics, California Agricultural Experiment Station 
Editor's Note: — During the last few years immense strides have been made in the way of breeding plants toward a definite 
ideal. So much so, in fact, that it is not an exaggeration to say that nowadays it is actually possible (within certain limitations, 
of course), to evolve a new plant that shall combine desired characters already existing in separate individuals. The steps by which 
this condition has been reached have both the romance and charm of a fairy tale. Many gardeners, however, are still somewhat in 
the dark as to the possibilities of hybridization, although the matter has so impressed the great seed-growing industry as to lead to 
quite new methods of work. One large concern, indeed, has recently secured the exclusive services of Dr. H. J. Webber as director of 
seed breeding, lately of the University of California and of Cornell, and before that known the world over for his work at Washington 
in making a hardy, long-staple cotton. A subject of this nature is perforce full of technical terms — many of which had to be made 
for the purpose — and cannot be presented in the words of the kindergarten; but we feel that Prof. Collins has acquitted himself ably 
in the task of laying before our readers, in as plain terms as practicable, an outline of the present status of knowledge of this newest 
and alluring development of the gardener’s craft. 
The present article is the first of a series of three that will cover the main points in different branches of plant breeding. 
rrr^IHE eternal desire to find something new ever has 
stimulated and molded the activities of students of 
gfe nature and the man dealing with plants has been, 
Tr indeed, no exception. 
It was only in the year 1694 that a definite beginning was 
made toward the solution of controlled plant production when 
Camerarius, a German professor of philosophy and a botanist 
as well, discovered through actual experiment that the pollen of 
plants was absolutely indispensable to the fertilization of the 
seeds, also that the pollen-producing parts of a flower are male, 
and the seed-bearing parts female. In the years that followed 
there was much theorizing and speculation on the problems of in- 
heritance, but no further real progress toward their solution was 
made until about the period of time covered by our Civil War. 
It was during this period that Johann Gregor Mendel, an 
Augustinian monk living in a monastery at Briinn, Austria, 
began searching for the answer to problems of heredity. He 
spent eight years making and studying hybrids between varie- 
ties of Peas. From these experiments, he discovered that when 
he crossed varieties differing in some one or more pairs of char- 
acters, such as green seeds and 
yellow seeds, the hybrid would 
have only one kind of seed. 
From cases of this kind where 
only one of the two parental 
characters appeared in the hy- 
brid he formulated his "law of 
dominance." The parental 
character which did not appear 
in the hybrid he considered as 
“recessive.” Among the seeds 
on the plants produced by the 
hybrids there appeared both the 
original forms in the proportion 
of 3 dominant to 1 recessive. 
This separating in the second 
generation of the parental char- 
acters which had associated to- 
gether in the seed of the hybrid 
Mendel called the “ law of segre- 
gation.” 
In the year 1866 Mendel gave 
to the world, in these laws, the 
key with the aid of which it was 
possible to unlock many of the 
secrets of heredity; but alas — 
everybody was then so engrossed 
with Darwin’s recently an- 
nounced theory of evolution and 
the origin of species that not un- 
til 1900, when Mendel’s records 
were again found, were they 
finally recognized at their true 
value. Previous to 1900 new 
INBRED AND CROSS-BRED PLANTS 
OF THE SAME SPECIES 
plants and animals were obtained only as chance happenings; 
but this old order has changed, giving place to new, more rapid 
and efficient methods made possible by the contribution of this 
Augustinian monk. 
The plant breeder can now almost make plants to order. 
Asked for a wilt-resistant Watermelon to save the Watermelon 
industry for Florida; and presto! the plant breeder takes the 
disease-resisting quality of an inedible Melon and combines it 
with the commercial Watermelon and gives it to the planter; 
wanted a particular breed of cattle without horns — the animal 
breeder produces it; and so it goes. 
Not only is it now possible to shuffle characters of plants and 
animals almost at will; but we are, thanks to the careful work of 
modern botanists and plant breeders, also learning the answers 
to some of those age-old perplexing problems involved in the 
mating of near relatives, known technically as inbreeding, and 
of the sudden appearance of unusual, grotesque forms. 
Very few people who deal with some kind of growing plants 
but have wondered about an occasional peculiar specimen 
among a large number of ordinary seedlings! What gardener 
has not noticed white stalks of 
Wild plants of the Sunflower family which are in nature highly cross 
fertilized. What three generations of inbreeding will do to them is 
shown by the two plants at the left. The large one is a cross-bred plant 
of the same species. One of the parents was the parent of the inbred 
plants and the other belonged to another variety of the same species 
a few Corn seedlings in his field 
or garden, and perhaps paused 
to ponder about it — would it 
turn green as it grew older? 
Surely he had never noticed a 
mature plant so lacking in green 
color! What florist has not 
found two or more flowers grown 
fused together; or the stems of 
plants flattened, covered with 
numerous leaves and terminated 
by many abnormally shaped 
blossoms on fine, slender stems? 
Any of us have seen now and 
then little puny, weak, dwarf- 
like plants when all the sister 
plants were vigorous and ro- 
bust, or, on the other hand, 
have been astonished at the re- 
markable size and vigor of a 
few plants among many ordi- 
nary ones. 
These odd forms are in most 
cases recessive characters which 
follow the Mendelian laws of 
heredity. The white Corn seed- 
ling one occasionally sees is a 
character of this kind. The 
thing that is to determine the 
production of a hereditary char- 
acter is called by breeders a 
“character determiner” or a 
"germinal factor” and is located 
372 
