Nov. 26, 1917 
Field Technic in Rod Row Tests 
4*3 
for the central rows and for the 3-row plots, respectively. For these 
tests the standard varieties used in the check plots in the spring-wheat, 
oats, barley, and winter-wheat tests have been used. 
The probable errors are often very large, owing to the small number 
of plots or rows in these tests in which many replications are studied. 
As the tests for the Farm Crops and Plant Breeding work are made in 
widely separated fields, except in the winter-wheat tests, it would seem 
that the conclusions for the particular crop year in question would be 
fairly sound. 
The method of replication used for the work is as follows: If there 
were 50 check plots in a particular test and 2 replications were to be 
studied, an average of plot 1 and plot 26, plot 2 and plot 27, etc., was 
taken. Similarly for 3 replications and 51 plots the average of plot 1, 
plot 18, and plot 35, etc. was taken. 
The value of replications in Haynes Bluestem wheat is given in Table 
XI. 
Table XI .—Value of replication of central rows and 3-row plots of Haynes Bluestem 
wheat (Minnesota i 6 q ) used as a check in the Farm Crops and Plant-Breeding tests 
Method of test. 
Num¬ 
ber of 
tests. 
Mean. 
Standard 
deviation. 
Coefficient of 
variability. 
Single central rows. 
15 
20.6±o. 261 
1. 50±0.185 
7.28 ±0.896 
2 replications. 
7 
20.6 ± .191 
•75± -135 
3-64± .656 
3 replications. 
5 
20.6± .323 
i.o7± .228 
5. i9±i. 107 
4 replications. 
3 
20. 7± .370 
• 9S± .262 
4.59±i. 264 
6 replications. 
2 
20.8± .167 
•35± -n8 
1.68 d= • 566 
3-row plots. 
15 
20.7 i .240 
I.38db .170 
6.67d= .821 
2 replications. 
7 
20.7 ± .250 
• 98± .177 
4* 73 i -853 
3 replications. 
S 
20.7± .314 
i.04± .222 
5.02±i.07i 
4 replications. 
3 
20. 7 ± .136 
• 35± *<>96 
i.69± .465 
6 replications. 
2 
20. 7± . X19 
.25± .084 
x.2i± .408 
Single central rows. 
Si 
25 
11. 7± . 100 
11.6± .174 
2.Old: .134 
i.29± .123 
17. 25±i. 187 
11. o8± 1.067 
2 replications. 
3 replications. 
17 
ir.6i .239 
i.46d= .169 
I2.60i1.487 
4 replications. 
12 
11.8± .193 
•99± -136 
8-37 ±i- i6 4 
6 replications. 
8 
ii. 6± .165 
.69± .116 
5.94il.002 
9 replications. 
S 
11.4± .241 
. 8odb .171 
7.02±l. 497 
3-row plots. 
51 
11.6i .157 
X.66± .in 
l4-3oi .974 
2 replications. 
25 
11.6± .158 
1.17± .112 
10.12i .975 
3 replications. 
17 
11.5± .128 
.78d= .090 
6* 76± . 782 
4 replications. 
12 
11.8± .162 
.83d: .114 
7-o6± .972 
6 replications. 
8 
11.8± .157 
,66± .111 
5.62i .948 
9 replications. 
5 
11.6± .148 
. 49i .104 
4.22i .900 
Designation of test. 
Farm Crops variety test 
Do. 
Do. 
Do. 
Do. 
Do. 
Do. 
Do. 
Do. 
Do. 
Plant Breeding Nursery 
Do. 
Do. 
Do. 
Do. 
Do. 
Do. 
Do. 
Do. 
Do. 
Do. 
Do. 
For the Farm Crops test of Minnesota 169 wheat there were only 15 
plots available. For this reason the Farm Crops results for the value of 
replications are less reliable than the Plant Breeding tests, where 51 
plots were grown. In the Farm Crops work for the central-row repli¬ 
cation studies the use of any number of replications from two to four 
seems about equally accurate. Six replications, as compared with two, 
gave a difference in the standard deviation of 0.40± 0.179. This is 
slightly more than 2 times the probable error. 
For the test of replications in the 3-row plots two or three replications 
appear to be about equally reliable. Four replications are much more 
accurate than three, the difference in the standard deviation of four 
