414- 
Journal of Agricultural Research 
Vol. XI, No. 9 
and three replications being o.6g±o.242. This is 2.8 times the probable 
error. The chances of a deviation as large as 2.8 times the probable 
error are 1 to 15.95. Six replications appear to be no more accurate 
than four replications. 
In comparing the test as made by the use of central rows and 3-row 
plots it would seem that for one, two, or three replications the central 
rows were about as accurate as the 3-row plots, four replications in 
3-row plots are apparently as reliable as six replications for central 
rows. 
For the Plant Breeding test two or three replications of central rows 
appear to be about equally reliable. Four replications seem to be about 
as valuable as either six or nine. The difference in the standard devia¬ 
tion as given for three or four replications is 0.47 ±0.217. This is of 
possible value. 
For the test of replications in the 3-row plots there is in general a slight 
progressive reduction in variability as the number of replications 
increases from one to nine. The largest reductions are from one to two 
and from two to three replications. The progress reductions between 
three and nine replications are only very small. 
In like manner the value of replications has been studied for the 
oat check plots. In a consideration of the results for central rows and 
3-row plots it is of interest to again call attention to the greater effect 
of competition in the Plant Breeding test between adjacent rows of oats 
than for the wheat tests. 
Data for a comparison of the value of replications in the oat tests are 
presented in Table XII. 
Table XII .—Value of replication of central rows and 3-row plots of Ligowa oats (Min¬ 
nesota 281) used as a check in the Farm Crops and Plant Breeding tests 
Designation of test. 
Method of test. 
Number 
of tests. 
Mean. 
Standard 
deviation. 
Coefficient of 
variability. 
Farm Crops variety test.. 
Single central rows. 
20 
6l. 2±0. 849 
5. 63 ±0. 600 
9. 2o±o. 981 
T)n . 
2 replications. 
10 
6l- 2± . 970 
4. 55 ± .686 
7.43±i. 121 
Do . 
3 replications. 
6 
61. 6±i. 013 
6l. 2±I. 020 
3. 68± . 717 
3 * 38 ± • 721 
i.88± .518 
. i6± . 054 
5*87± .626 
4 - 37 ± *659 
3* 7 °± • 720 
3. i6± . 674 
i* 37 ± -377 
1. 48 ± -499 
6. 81 ± . 423 
5. 97± 1.162 
Do . 
4 replications.... 
5 
5. 52±i. 177 
3. 05± . 840 
■ 26± .088 
Do . 
6 replications. 
3 
61. 6± . 732 
61. $± . 076 
61. 6± .885 
61. 6± . 932 
62. 2±X* 019 
Do. 
9 replications. 
2 
Do . 
3-row plots. 
20 
9 * S3± J. 016 
7. 09 ± 1.069 
5 * 95 ± i* 159 
5 - 13 ±1.094 
2. 20± . 606 
Do. 
2 replications. 
10 
Do . 
3 replications. 
6 
Do. 
4 replications. 
5 
61. 6± .953 
62. 3± -534 
62. 3 ± . 706 
58. 3 ± • 598 
Do . 
6 replications... 
3 
Do. 
9 replications. 
2 
2. 3 8± .803 
11. 68± . 782 
Plant Breeding Nursery.. 
Single central rows. 
59 
Do. 
2 replications. 
29 
58. 9 ± • 587 
4 * 69 ± .415 
7 * 97 ± • 706 
Do. 
3 replications. 
19 
58 - 7 ± -484 
3. 13 ± .342 
5 - 33 ± .583 
Do. 
4 replications. 
14 
58. 9 ± *633 
3. Si± .447 
5 - 96 ± . 760 
Do. 
6 replications. 
9 
58 . 3 ± -645 
2. 87 ± .456 
4 * 92 ± . 782 
Do. 
9 replications. 
6 
58. o± .388 
i- 4 i± • 275 
2-43± .473 
Do. 
3-row plots. 
59 
S 7 - 2 .± -587 
6. 68± . 415 
II. 69± . 733 
Do. 
Do. 
2 replications. 
3 replications. 
29 
19 
57* 7± .510 
57. 2± .532 
4. 07± .360 
3 * 44 ± *376 
7*os± .624 
6. 02 ± , 659 
Do. 
4 replications. 
14 
57. 6± . 508 
2. 82± .359 
4. 89 ± .623 
Do. 
6 replications. 
9 
57* o± .551 
2. 45 ± . 390 
4. 30± .684 
Do. 
9 replications. 
6 
56. 9 ± . 240 
. 87± . 169 
i.S3± .298 
