648 PRACTICAL PROBLEMS 



Under this system each ear of corn, for example, is planted 

 in a separate row, and as many rows will be used as there are 

 ears in the first selection. The ear in the book and the row in 

 the field then have the same number. 



Suppose we are starting an experiment on breeding for " high 

 oil." It is the first year, and we have the twenty highest oil 

 ears that could be found out of the seed at hand. These ears 

 will be numbered, not from i to 20, but from 101 to 120. 

 Next year they will be numbered 201 to 220, or 225, or to what- 

 ever number of ears may be available. The hundreds always 

 show the number of years or generations of improvement, and 

 the rest of the number shows the field number of the ear and of 

 the row in which it is planted. Thus, if we find ear No. 612, 

 we know that it is the sixth year of the experiment, or the 

 sixth selection from the original stock, and that it is planted in 

 row No. 12 of that year's field. This ear, like all others that 

 have been analyzed, has its laboratory number, or " annual ear 

 number," by which its composition may be traced ; but its 

 " pedigree number," 612, for example, is the one from which 

 its breeding is traced. A sample page from such a register 

 book shows the system in full, there being no other records 

 except the chemical analyses. This is the entire record of the 

 high-oil corn for 1902. (See table on opposite page.) 



Selecting 607 of this table, for example, we see by the record 

 that its dam of the year before was No. 504 ; that its number 

 in the chemical laboratory was 3923; that the ear was 6.5 

 inches long, its tip circumference 4.8 inches, and its butt cir- 

 cumference 5.8 inches; that it had 12 rows, and that each row 

 had an average of 48 kernels ; that the ear weighed 5.3 ounces, 

 and had 7.13 per cent of oil. We learn, too, that it was planted 

 in row No. 7, which was 71^$ hills long and produced 85 pounds 

 of corn, or at the rate of 63.5 bushels per acre; that there 

 were in all 140 ears of corn in the row, the average oil content 

 of which was 6.65- 1 



As a practical detail in corn breeding, it may be remarked 

 that the best ears are always planted in the middle rows to give 

 them the advantage in the matter of pollination. 



1 As determined by a composite sample of twenty average ears. 



