Relation of Size of Seed and Sprout Value to Yield 33 
The yields of wheat during the 2 years of these tests were 
quite normal. The averages of all the winter wheat yields were 
at the rates of 31 and 48 bushels per acre during 1914 and 1915 
respectively. The corresponding spring wheat yields were at 
the rates of 13 and 17 bushels per acre. This was a normal 
difference in yield for winter and spring wheats — the former 
representing a well adapted, and the latter a poorly adapted 
crop. 
It is seen from the summary data in table 15 that, as an 
average for both winter and spring wheat during the 2 years, 
the small seed weighed 66 per cent as much as the large seed 
and had a sprout value 68 per cent as great. The laboratory 
germination of the two grades was practically equal — the small 
seed germinating one per cent less as an average. 
When planted alone, the small seed produced 6 per cent 
fewer culms, and in competition 18 per cant fewer culms than 
the large seed. The yield of grain was 11 par cent smaller for 
the small seed planted alone and 24 per cent smaller in com- 
petition than for the large seed. The straw yield was 6 per cent 
smaller for the small seed alone and 25 per cent smaller in com- 
petition than for the large seed. The total plant yield was 7 
per cent smaller for the small seed planted alone and 25 per 
cent smaller in competition than for the large seed. 
It is evident that, when planted alone in equal numbers, 
small seed was (on an average) 11 per cent and 7 per cent inferior 
to large seed in grain and total production, respectively. Com- 
petition reduced the relative yield of small seed in grain and 
total production 15 and 20 per cent respectively. 
EFFECT UPON TOTAL YIELD OF COMPETITION BETWEEN LARGE AND SMALL 
SEEI>S 
The investigation reported in tables 16, 17, 18, and 19 in- 
dicates the effect upon total yield of wheat from planting large 
and small seeds of the same variety in competition. Large and 
small seeds of a given wheat variety were alternated in 5-row 
plats 7 § feet long. The seeds were spaced one-half inch apart by 
hand. The two grades were also planted alone to secure the 
comparative yields free from grade competition. A difference 
between the yield of the two grades mixed and the average yield 
of the two grades planted alone indicates the effect of com- 
petition upon total yield. This test was made with two varieties 
each of winter and spring wheat during 1914 and 1915. The 
plats were systematically distributed and were replicated 5 and 9 
times for the winter and spring wheat respectively. Being of the 
same variety, it was not possible to distinguish and separate the 
