Relation of Size of Seed and Sprout Value to Yield] j T 69 
Table 45 — Relative yields of large and small seed planted alone 
and in competition 
Crop 
Investigator 
Date of 
publication 
Duration 
of test 
Relative yields 
Alone 
Competition 
Large 
Small 
Large 
Small 
Winter wheat 
Oats 
Kiesselbach, T. A. 
and Helm, C. A... 
Montgomery, E. G 
1917 
1912 
2 
1 
Per cent 
100 
100 
Per cent 
89 
93 
Per cent 
100 
100 
Per cent 
76 
80 
Av 
100 
91 
100 
78 
In general the results indicate: 
(a) When space-planted to permit maximum development, a 
higher individual plant yield is obtained from large than from 
small seeds. As an average for all investigations, this difference 
amounts to 17 per cent. This is not to be regarded as an in- 
heritable quality, but rather as an immediate advantage due 
to a more vigorous initial growth resulting from a greater re- 
serve food supply in the seed. 
(b) When planted in equal numbers at a rate optimum for 
large seed, a lower yield is obtained from the small than from 
the large seed. As an average for all investigations, this differ- 
ence amounts to 12 per cent. This comparison resolves itself in 
a measure into a rate-of-planting test. The optimum number of 
plants, per unit area, from large seeds is too thin for maximum 
results from small seeds. 
(c) When planted in equal weights, at a rate optimimi for 
the large seed, all three grades — large, small, and unselected — yield 
ec[U&,lly. As an average for all investigations, large and small seed 
yielded alike, and the unselected seed yielded 1 per cent more 
than the large. This also seems to be a matter of rate planting. 
The shortage in yield of plants from small seeds is overcome by 
planting a greater number of seeds. 
(d) When light and heavy seeds (or large and small) obtained 
from a fanning mill are planted in equal volumes as with a drill 
set at a uniform rate, slightly smaller yields are apt to result 
from the small seed. As an average for all investigations, this 
difference amounts to 4 per cent. The difference in favor of 
large or heavy seed as compared with the original unselected 
seed is very slight, and probably so small as to have little practical 
significance. As an average for all tests it amounts to 2 per cent 
L 
