Experimental Error in Crop Tests 
41 
for five years and was greatly reduced in size and vigor. 
The results indicate the error which might be expected if 
two inbred parents were to be compared with their hybrid 
and the original check seed. In alternating three-row plats, 
the inbred corn yielded 36.9 per cent as much as the hybrid 
seed, while in the alternating single-rovv^ plats it yielded 31.1 
per cent as much. When compared in the same hill, the 
inbred seed yielded 20.7 por cent as much as the hybrid seed. 
Because of competition with the larger plants in the same 
hill, the inbred corn yielded relatively 44 per cent too low. 
while in alternating single rows, it yielded relatively 16 per 
cent too low. 
SU3IMARY OF PLAT COMPETITION STUDIES 
The effects of single row plat competition upon compara- 
tive grain yields, are summarized for wheat, oats, and corn, 
in Tables 18 and 19. These data are taken from Tables 1 
to 7 and 11 to 17. The ratios given for the comparative 
yields in blocks are for the middle row or middle three rov/s 
of either three-row plats or five-row plats, except in 1913, 
when the block-rows were not harvested separately. 
VARIATIOX OF STAND AS A SOURCE OF ERROR IX YIELD 
TESTS AVITH CORX 
In order to secure information regarding the effect of 
variation in stand upon the accuracy of comparative corn 
tests, 2,000 hills of corn were planted in 1914 and 8,500 hills 
in 1917, in which were methodically distributed two, one and 
no-plant hills among hills with a full stand of three plants. 
Each hill was harvested separately. The results are contained 
in Tables 20 and 21. 
In 1914 (Table 20), when surrounded by hills having a 
full stand of three plants, the respective relative grain yields 
of three-plant, two-plant and one-plant hills were 100, 82, 
and 74. In 1917 the corresponding relative yields were 100, 
83, and 50. 
In 1914 (Table 21), when three-plant corn hills, other- 
wise surrounded by a full stand of three plants per hill, were 
adjacent to (1) one hill with two plants, (2) one hill with 
one plant, (3) one blank hill, (4) two blank hills, the respec- 
tive grain yields per hill were 3 per cent, 5 per cent, 13 per 
cent and 43 per cent greater than when surrounded entirely 
by three-plant hills. 
