Multiplying plot.
Seed for a multiplying plot of ten acres or more should be taken only from the selected rows of the breeding plot, and may include all good seed corn which is not required for the breed ing plot. This seed should be well mixed to gether. The corn in the multiplying plot should be protected carefully from foreign pollen, and all inferior stalks may be detasseled, to elimi nate their influence on neighboring plants. The exact yield of the multiplying plot should be deter mined and registered.
Commercial field.
The seed for the commercial field should com prise only the very best obtainable seed corn from the multiplying plot. The exact yield of the com mercial field should always be determined and reg istered. From the commercial field the finest ears may be selected and sold to the trade as registered seed corn.
Description of individual ears.
Register number.-As soon as any ear of a given variety and strain is selected to be planted in a breeding plot by a given breeder it is given a register number, which must, of course, represent that particular ear only and for all time. By using a certain system of numbering, we not only are able to designate the ear but can show at the same time the year of its breeding or the number of its generation, and the field row in which it is planted. This we do by starting the first year in the 100 series, numbering the ears to be planted in suc cession from 101 to 148 and 151 to 198, and the second year starting the 200 series, running from 201 to 248 and 251 to 298, and so us, as far as may be necessary, starting each succeeding year with a higher hundred.
Dam number.—The "dam number" is the "regis ter number" of the parent ear and is useful in tracing the pedigree record from year to year back to the source.
Annual ear number.—In order to designate the two hundred or more ears selected from the field, each one is given an " annual ear number," which runs in a series from one up to two hundred or more. This number is only temporary, to serve while working on the corn for the final selection of seed ears, and when the seed ears are selected to be planted, each is given a permanent "register number," as explained under that heading.
If desired, a record may be kept of certain phys ical and chemical properties, as length, circum ference and weight of ear and cob, per cent of grain, number of rows of kernels on the ear and the average number of kernels in the row, and per centage of protein or oil if determined.
Performance record of field rows.
The field row or breeding row numbers should correspond, for the sake of convenience, with the register numbers of the ears planted. For example, ear Register No. 101 should be planted in Field Row No. 1. The percentage of stand and the yield per acre of each field row should be determined and recorded.
On the same sheet with the complete year's record of the breeding plot appear the records of the multiplying plot for the same year, and for the next year following, and also the records of the commercial field for the same year and for the next two years. If the record sheet is for the breeding plot for 1905, it is important finally to record on the same sheet the record of the multiplying plot for 1906 and of the commercial field for 1907, and for convenience and comparison it is well to record on the same sheet the yield of the multiply ing plot for 1905, and the yields of the commercial field for 1905 and 1906. If a breeding plot were started in 1905, the breeder could have both a breeding plot and a multiplying plot in 1906, and a breeding plot, multiplying plot and commercial field in 1907 ; and from the 1907 crop on the com mercial field he could sell seed corn with a regis tered pedigree of three years, one year in the breeding plot, one year in the multiplying plot and one year in the commercial field. In 1910, he could sell seed corn from his commercial field with a registered pedigree of six years, four years in the breeding plot (1905, 1906, 1907 and 1908), one year in the multiplying plot (1909), and one year in the commercial field (1910).