Weight of mother 
roo 
1916] PRITCHARD—SUGAR-BEET BREEDING 441 
poor plants would receive pollen of equal average quality, and hence 
the better mothers should produce the better average progeny. 
Moreover, the fact that insects visit several flowers before leaving 
a plant probably causes a considerable percentage of selfing, even 
Avera ge ounces of sugar per root in progeny in 1908 
/n ounces 
SS a ve ele a a eS 
/] al nd con ee ae ee a et 
@ 
@ /4 
S77 
‘4 
20 
Fic, 19.—To accompany table XXT 
though the plant may prefer foreign pollen. If hereditary differ- 
ences occur in mother roots and are transmitted to their progeny, 
they are certainly obscured by fluctuations caused by irregularities 
of the soil, which influence Average percentage of sugar in 
the qualities of both mother progeny In oF 
toot and progeny, and thus , sss ssa 88 8 
baffle the breeder’s attempt 3 = Bee es Oo ee ‘ 
to discover real differences. Ped 
By planting each family s 63 
To-20 times and usingacon- 5s “4 Sis a 7d a 
siderable number of checks z 7 — ~ 
it may be possible to dis- § 20 ae 
tinguish hereditary differ- © 2: 
ences between their progeny, $ 26 
but this would hardly apply = 
to mother roots. In fact, 3 | 
these results seem to con- Fic. 20.—To accompany table XXII 
demn the customary practice 
of selecting mother roots by current physical and chemical means. 
Taking roots at random would certainly be much cheaper and 
apparently fully as effective. 
