. Bulletin. 1901-13. Agriculture; Agriculture. 38 EXPERIMENTS IN WHEAT BREEDING. cent in the extreme cases, although the appearance at harvest time was fairly uniform. These plats have been combined in various ways in order to study the yields. The results are shown in Table XV. EFFECT OF REPETITION IN REDUCING ERROR. The first part of Table XY shows the 224 blocks combined in various ways, namely, 56 groups of 4 blocks each when every^ fifty- sixth block was taken, 28 groups of 8 blocks each when ever}^ twenty-eighth block was taken, and 14 groups of 16 blocks each when every fourteenth block
. Bulletin. 1901-13. Agriculture; Agriculture. 38 EXPERIMENTS IN WHEAT BREEDING. cent in the extreme cases, although the appearance at harvest time was fairly uniform. These plats have been combined in various ways in order to study the yields. The results are shown in Table XV. EFFECT OF REPETITION IN REDUCING ERROR. The first part of Table XY shows the 224 blocks combined in various ways, namely, 56 groups of 4 blocks each when every^ fifty- sixth block was taken, 28 groups of 8 blocks each when ever}^ twenty-eighth block was taken, and 14 groups of 16 blocks each when every fourteenth block was taken. The 56 groups of 4 blocks each were divided into 4 sets of 14 each and the 28 groups of 8 into 2 sets of 14 each. This division into sets was for the purpose of having an equal number of blocks for comparison in each case. We find ilhistrations of a combination of high-yielding plats and low-yielding plats such as were noted in Table XII. For example,. r ' r 7. re 71 >6 7* }e 6, 93 6. ^e S\ 'e 6tS >b 7' tz S{ 77 r. te 7i o 6t, 6-i '8 6, TO r ~6t 19 61 '3 6- f3 6i W 7i f9 6i i7 GW ~\ 6 '5" 61 4 6-U 6t p/ 6 •9 6^3 (.76 i 1 _J 1 1 7^19 7S '6 7< '2 «1 •/ 6. ^ &. P3 ehX I f7 6f2 el '3 G -,7 6. 9 6 »^ e ro Si 1 _1_ 1 ' Fig. 11.—Diagrams of plats of Turkey wheat, showing the arrangement of 224 blocks (each feet square) when combined in groups of adjacent blocks, with the average yield for each group: A, Groups of 4; /?, groups of 8; C, groups of HI. when the blocks are repeated 4 times the range in yield varies from an average of grams per block to an average of grams per block, a difference of 32 per cent. If varieties were being tested by the same system, this variation would be more than we might expect in the yields of dillerent kinds. When the blocks are repeated 8 times the average variation ranges from to grams, a difference of 90 grams, or 14 per cent. By repeating 16 times the extreme variation is reduced to 47
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