560 PLANT BREEDING 
This method of selection is productive of good results, but 
has some disadvantages. It requires much time and labor as 
well as the use of much ground. Since each crop is grown 
from seed furnished by many plants selected the previous year, 
the progeny of many plants are involved and the yield of a crop 
Fic. 485. — Dakota Amber Sargo, a strain that matures much earlier and 
is more drought-resistant than the South Dakota No. 341 from which this 
new strain was produced by selection. After Dillman. 
is the average yield of the descendants of many plants varying 
in capacity and heritage for high yield. Many of the plants 
in the selection are likely to be heterozygous for the character 
and consequently will not breed true. Races obtained by this 
method of selection usually lose their desirable features unless 
selection is continued. 
Pedigree Culture. — The value of pedigree cultures was well 
demonstrated by De Vries and Mendel. In the method of 
selection by pedigree cultures, a single plant is selected, and 
from its progeny, which are carefully guarded, the best indi- 
