1916] PRITCHARD—SUGAR-BEET BREEDING 429 
of a crop as subsequent selections. Sugar-beet varieties are seldom 
distinguishable from one another morphologically, however, and 
_ as they have nearly the same descent, some doubt may be expressed 
regarding the existence of real variety differences. In order to 
determine the truth of this hypothesis, 78 families of Morrison’s 
Kleinwanzleben? which made the best records for percentage 
and yield of sugar at Madison in 1912, and 52 families of Madison 
Original Selections were used in a comparative merit test in rg14. 
3 
Bes / 
RECCITMINTN 
eS! oe / \ x 
AL 2 2 L L {e7 ivo 12 9 
Value of families for percent, ¢ Fab fee aas expressed 
in percentage 
Fic. 1—Comparison of two kinds of sugar-beet material used as foundation 
stock, 
A progeny row of each family (seed of a single beet) was planted 
between two check rows of Kleinwanzleben’s Original. When 
the beets were harvested, each progeny row was compared with the 
average of its two contiguous checks by giving the latter a value 
of 100 and computing the value of the progeny row upon this 
basis. In fig. x the vertical line represents the values of the check 
rows for percentage of sugar; the frequency polygons A and B, 
Morrison’s Kleinwanzleben and Madison Original Selections, 
respectively. The frequencies were reduced to percentages by 
*In ror2 these families were grown from seed of Fairfield roots containing 20-22 
per cent sugar. 
