Nov. 26, 1917 
Field Technic in Rod Row Tests 
405 
CORRELATIONS FOR HEIGHT COMPETITION 
The effects of the height of adjacent rows on the yield of the border 
rows may be first considered. The method of determining such effect 
is as follows: The yield of the border rows in bushels per acre was com¬ 
puted and the yield of the right border compared with that of the left. 
If the left border yielded the most, the result is given as a positive, or 
plus (+) yield, the difference being expressed in bushels per acre. If 
the right border yielded the most, the yield difference is a negative, or 
minus (—) result. 
In somewhat similar manner the height of adjacent rows was com¬ 
pared. If the row of the variety or strain near the left border row was 
taller than the variety near the right border row, the result is given as a 
positive, or plus ( + ) difference, in inches; if the row near the right 
border was taller, the result is given as a negative, or minus (—) difference, 
in inches. 
It should be noted that with the plant breeding barley work the 
height was taken in centimeters. 
Correlation tables are then made in which the comparative yield of 
the border rows of the same variety is correlated with the comparative 
height of adjacent rows. If there is an effect on yield of border rows 
of the same variety owing to the height of adjacent rows, a negative 
coefficient should be obtained. A representative table for barley is 
given (Table II). 
Table II .—Correlation between the differences in yield between the border rows of a variety 
of barley and the differences in height (in centimeters) between the neighboring border 
rows on the leH and right, respectively. Barley Plant-Breeding Nursery, igi6 
[Left greater — +. Right greater =» —.] 
