442 BOTANICAL GAZETTE [DECEMBER 
SELECTION OF FAMILIES.—Sugar-beet families are selected 
upon the basis of percentage and yield of sugar. Extreme selection 
in either direction is avoided, as a maximum yield of sugar is usually 
associated with a moderately high percentage of sugar, while an 
Average weight we agian’: 
49/0 
roots im ounces f 
Average percentage of sugar in progeny in 1909 % 1 Bae F gas? - pent 
Pies s2e5e723. 5 
z ~ = = = “ ¢ Ps < 8 oe 
23 
ay * S29 Emad 
a: * ES 
%, 7) 33 bed sa < BER 
ad _—— 
“Ss gp tg 
se 7 oho 
SE ve = SF yo at 
Fic. 21.—To accompany table XXIII Fic. 22.—To accompany table XXIV 
extremely high percentage is generally indicative of a low tonnage. 
the presence of inorganic salts lowers the percentage and pre- 
vents the extraction of about an equal quantity of sugar, selection 
for extractable sugar is the most ideal method to employ, but it has 
Average weight of progeny roots 
in ounces in 1908 
i l fi l fi / vA J / ‘] 
>— 
Weight of mother root 
in ounces in (906 
S 
Fic. 23.—To accompany table XXV 
the disadvantage that additional chemical work is required to 
determine the coefficients of purity. Relative merits, therefore, 
are more economically determined from the percentage of sugar 
and total yield of sugar. 
VARIABILITY OF PROGENY ROWS.—Progeny rows show con- 
siderable variation even when the stand of beets is compara- 
