444 BOTANICAL GAZETTE [DECEMBER 
effects that would eliminate such factors as family hereditary 
differences, and the possible use of too small a number of plants 
to form a representative sample of the family. This was accom- 
plished by plotting the mean values of consecutive progeny rows 
Row numbers 
goo SG > esegeceseseeseseSR8e€R 
~ Law 
os Pe Salat Se fe SoS 
PP rE Lhe 
lh Alaades 
) . 
= 
rd 
Pad wl? 
om 
¢ 
e 2 
fea: 
ry tw 
na Ha A 
tA SE ee | 
Fic. 24.—Effect of soil irregularities on percentage of sugar of check and progeny 
rows, strip 1, Madison, 1912; solid line indicates progeny rows; broken line, check rows. 
Rrcentage of sugar 
3 
™ 
iy, 
for percentage and yield of sugar in the same order as the rows 
occurred in the field. Family differences in percentage or yield 
of sugar which show regular progression in direction are assumed 
Row numbers 
ESFSSLISSSSSSRSRSRSSsgZy 
a/é + * ss 1 atl | _— 
S15 Pa a a sh 1 PUN fe Bh | 
2/4 Mtoe AE aR | os ma 
= /3 Mee TI PY ys 
=” 7 
S// 
= /0 
oe 3 ae fae Ee 
f sugar of check and progeny 
check 
Fic. 25.—Effect of soil irregularities on f g . 
rows, strip 2, Madison, 1912; solid line indicates progeny rows; broken line, 
to be due to the inequalities of the soil, while differences which 
show no such regularity may be due either to local soil disturbances 
or to other causes. A check on the results of the foregoing method 
is afforded by plotting the mean values of progeny rows of contigu- 
