292 GENETICS IN RELATION TO AGRICULTURE 
selection of best plants in order to maintain the improvement already 
gained. One of the earliest breeders to use this method was André 
Lévéque de Vilmorin, who began selecting carrots about 1830. Soon 
thereafter selection of sugar beets for seed production was begun in 
France and Germany, first according to form of the root alone, but later 
according to specific gravity and actual analyses of sugar content. 
Mass selection later became the principal method of improving small 
grains in Germany, and it has been known as the German method of 
“broad breeding.”’ The earliest prominent breeder of small grains was 
W. Rimpau, who began his work with rye in 1867 and developed the 
famous Schlanstedt variety. Later he worked with wheat extensively, 
first by mass selection and, more recently, by hybridization of varieties 
and subspecies. Although there have been scores of successful breeders 
of each of the important small grains in Germany, Rimpau was the 
first to engage in this work on a large scale. 
Mass selection in maize was begun as early as 1825, when J. L. 
Leaming, of Ohio, began the selection of best ears from his field for seed 
corn. By repeating this process he soon developed a superior strain 
that came to be known as the Leaming variety. The same simple 
method was employed in originating Ried Yellow Dent (1847), Morley 
Prolific (1876), and Boone County White (1885). The famous Illinois 
corn-breeding experiments, which will: be described in later chapters, 
were begun in 1896 by Cyril G. Hopkins, then Professor of Agronomy 
in the University of Illinois. Among the other investigators who have 
participated in this undertaking are East, Shamel and L. H. Smith. 
The general result of the project has been the most convincing proof of 
the efficacy and practicability of mass selection in corn, not only for the 
chemical and physical characters of the grains but for other characters 
of the corn plant as well. 
The improvement of cotton by mass selection has doubtless been 
practised for centuries. Authentic records of the earlier methods used 
in foreign countries are scarce, but the characteristic variability in 
length of fiber, combined with the very practical value of increasing the 
average length, must have appealed to growers, at least in the more prog- 
ressive cotton growing regions of the world. IntheSouth Carolinaislands 
according to Webber the sea island types of cotton have been developed 
by consistent mass selection for early maturity, increased length of lint, 
and greater productiveness from a West Indian perennial type which 
was originally unsuited to conditions under which its derivatives 
are now grown so successfully. Mass selection in cotton has been 
resorted to also in the campaign against various plant diseases, 
particularly cotton wilt, and for early maturity to avoid the ravages of 
the boll weevil, 
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