Hayes and Garber - Cucurbit Breeding

RESULTS OF SELECTION WITH SELF-FERTILIZED CROPS 119
best seed on the spike would yield correspondingly the best plant.
Le Couteur and Shirreff placed all the emphasis on the original
plant selection, while Hallett believed he could improve the progeny
of an individual plant by further selection. Needless to say,
Hallett made no progress after the initial selection. A number of
his improved varieties were introduced and widely grown.
Louis Leveque de Vilmorin formulated a breeding principle
as a result of a series of experiments performed by himself and
his father which was published in monograph form (1852).
These early studies were carried on with vegetables and the conclusion
was reached that the only way to determine the breeding
value of a plant was to grow and examine its progeny. Much
study was made by the younger Vilmorin with the sugar beet.
This is not a self-fertilized plant, but the principles learned
have a direct bearing on selection with self-fertilized crops. In
the first few years the problem of determining the sugar content of
mother beets without injury to the roots received particular
attention. Weighing a small ingot of silver in the juice extracted
from a small piece of root was found to be an accurate method of
determining density and thus sugar
content. Roots of similar
sugar content were then used as mother plants and their breeding
nature determined. Some gave progeny with high sugar content
without pronounced variability; other mother plants gave variaable
progeny some of which were high in sugar content and others
much lower, while some mother beets produced progeny of such
inferior sugar content that all were immediately discarded.
Later the sugar content was determined by means of polarized
light (Babcock and Clausen, 1918). As an example of his
results may be mentioned a strain of beets which, after three
years' selection, gave juice with an average density of 1.087
while unselected seed grown in the same field gave an average
density of only 1.042. Andre Leveque de Vilmorin produced a
desirable cultivated form of carrot by three years of selection from
wild forms. Louis de Vilmorin also made a collection of wheats
and other grains from all parts of the world. After 50 years
of selection within isolated lines of wheat, no notable change
was observed (Hagedoorn, A. L. and A. C., 1914).
Willet M. Hays, formerly of the Minnesota Experiment Station,
was the first in America to adopt the "Vilmorin method"
for small grains. In 1891 he introduced what is known as the
centgener method of grain breeding (Hays and Boss, 1899).