Mar. 24,1923 
Permanence of Variety in the Potato 
955 
Tabus VIII .—Effect of growth conditions on the form of Early Ohio Tubers 
Lot 
No. 
Place grown. 
Year. 
Form index 
f len ^ h ') closes. 
V width / 
To¬ 
tal 
num¬ 
ber 
of tu¬ 
bers. 
Mean index. 
0.90 
1.10 
1.30 
1.50 
1.70 
x.90 
2.10 
2 
Duluth. 
1919 
14 
no 
38 
2 
1 
I. I 4 ± 0 . Ol 
2 
University Farm sand 
loam. 
1919 
1 
3 
17 
25 
13 
1 
60 
1. 65± .02 
2 
University Farm, clay 
loam. 
1919 
13 
17 
30 
44 
10 
1 
105 
1. 59 ± - OI 
2 
Grand Rapids. 
1919 
22 
67 
39 
12 
1 
141 
1. 36± •01 
7 
Grand Rapids. 
1919 
15 
67 
3 ° 
11 
1 
124 
1. 36± .01 
2 
Grand Rapids. 
1920 
I 
28 
28 
4 
71 
1. 23 db • 01 
7 
Grand Rapids. 
1920 
I 
14 
30 
1 
i 
45 
1. 23 db . 01 
Table VIII shows the number of the lot, the place grown, the year, 
the frequency distribution according to the index of width to length, 
and the mean index for each lot. Early Ohio tubers grown at Duluth 
in 1919 were relatively short, very broad, and somewhat flattened, hav¬ 
ing a mean ratio of width to length of 1 to 1.14. An example of this 
form of tuber is shown in Plate 1, D, which shows the original form of lot 
6 as obtained from Duluth in 1916. At University Farm, in 1919, on 
sandy loam soil the tubers were elongated, cylindrical in form, with a 
mean ratio of width to length of 1 to 1.65. On clay soil at University 
Farm the tubers were relatively thicker, broader, and shorter than those 
produced on the sand, having a ratio of width to length of 1 to 1.44. At 
Grand Rapids the tubers tended to be somewhat similar in form to those 
grown at Duluth but had less breadth and were slightly more elongated, 
having a mean ratio of width to length of 1 to 1.35 in 1919 and 1 to 
1.23 in 1920. The difference in form obtained in 1919 and 1920 shows 
the effect of seasonal conditions on the form of tuber. 
The results presented show that the mean index of the ratio of width 
to length of tubers can be used to detect changes in the form of tubers 
of the Early Ohio variety. 
This method was used in 1919 and 1920 in ascertaining whether any 
difference in form of tubers existed between the lots of Early Ohio which 
were being tested. The results are presented in Table IX, which gives 
the number of the lots, the place and year grown, the frequency dis¬ 
tribution according to their index number of width to length and the 
mean index number of each lot. 
