Relation of Size of Seed and Sprout Value to Yield 47 
The average germination of the two spring wheat varieties was 
quite uniform for the three grades of unselected, large, and small 
seed. The relative seed weights were respectively 100, 117.3, and 
78.4, while the corresponding sprout values were 100, 110.4, and 
71.8. The germination for the various grades was fairly uniform. 
The relative numbers of culms were respectively 100, 102.3, and 
94.6; the relative grain yields were 100, 111.8, and 92.3; the 
relative straw yields were 100, 104.5, and 97.0; and the relative 
yields of total dry matter were 100, 105.7, and 96.3. With the 
spring wheat, the large seed outyielded the unselected for grain 
11.8 per cent, while the grain yield of the small seed was 7.7 per 
cent inferior to the unselected seed. 
The summary results for both winter wheat and spring wheat 
(table 25) indicate a distinct advantage for the large as compared 
with the unselected seed. This advantage is greater for the 
spring wheat, which may be due to the fact that it is a more 
poorly adapted crop than the winter wheat. Because of a longer 
growing season and more favorable early growth conditions for 
winter than for spring wheat, the initial advantage of the large 
seed is less marked for the winter than for the spring wheat. 
WHY SMALL SEEDS YIELD LESS PER ACRE THAN LARGE SEEDS WHEN PLANTED 
IN EQUAL NUMBERS AT THE NORMAL RATE FOR THE LARGE SEED 
Thruout all of the comparative yield tests for large and small 
seeds reported in this paper, the large seeds have given a greater 
yield than the small seeds when planted in equal numbers at the 
normal rate for the large seed. 
While there has been a slight reduction in field germination 
for the small seeds in some instances, this decrease has not been 
relatively as great as the decrease in yield. In order to determine 
whether the characters of growth differed for the individual plants 
grown from large and small seeds, such grades of Scotch Fife and 
Marquis spring wheat and Klierson oats were space-planted 6 by 
10 inches apart and grown to maturity in 1916. This plan per- 
mitted maximum development for the plants. The differences 
in resulting growth may be attributed to the size of seed rather 
than to any environmental differences. The results follow in 
table 26. 
As an average for the spring wheat and oats, the small seeds 
planted weighed 52 per cent as much as the large seed. With 
the individual plant of the resulting crop, the small seed compared 
with the large produced 80 per cent as many culms per plant; 
72 per cent as high grain yield ; 77 per cent as great straw yield ; 
and 77 per cent as great total yield. This inferiority of individual 
plant development from small seeds may account for the smaller 
