6 Nebraska Agricultural Exp. Station, Research Bui. 11 
When planted alone, the small seeds produced 6 per cent fewer 
culms and in competition 18 per cent fewer culms than the large. 
The yield of grain was 11 per cent smaller for the small seeds 
planted alone, and 24 per cent smaller in competition than for the 
large seeds. The straw yield was 6 per cent smaller for the small 
seed alone, and 25 per cent smaller in competition 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. 
8. Competition between alternating plants of two wheat 
varieties may be very marked. Thus, in 1914, when grown at 
the normal rates of planting, the yields of grain, straw, total 
crop, and number of culms for Big Frame winter wheat were 
respectively 90, 88, 89, and 80 per cent as large as for the Turkey 
Red. But when grown in competition, the Big Frame yields 
were respectively only 55, 70, 67, and 68 per cent as large as for 
the Turkey Red. The relative competitive qualities of these two 
varieties were reversed in 1915, due to a great difference in 
climatic conditions. However, the effect of variety competition 
is very apparent. Planted alone, the yields of grain, straw, total 
crop, and number of culms for Big Frame winter wheat were 
respectively 82, 105, 99, and 94 per cent as large as for the Turkey 
Red. In competition, these Big Frame yields were respectively 
120, 128, 125, and 117 per cent as large as for the Turkey Red. 
Similar (tho not quite so striking) results were obtained for 
spring wheat. These investigations suggest that competition 
may play a very important role in the natural improvement of 
cereal crops. 
9. In a 2-year yield test of unselected, large, and small seeds 
of two winter wheat varieties, the average relative seed weights 
were 100, 134.6, and 86.9, with corresponding sprout values of 
100, 133, and 92.3. The grain yield of the large seed was 2.3 
per cent superior to the unselected seed, while the grain yield 
from the small seed was 3.1 per cent inferior. 
The 2-year average relative weights of unselected, large, and 
small seeds of two spring wheat varieties were respectively 100, 
117.3, and 78.4, while the corresponding relative sprout values 
were 100, 110.4, and 71.8. 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. 
In these tests, the seeds were planted in equal numbers at a 
normal rate for the large seeds. 
10. When two grades each of spring wheat and oats were 
space-planted to permit maximum plant development, the small 
