202 DOMESTICATED ANIMALS AND PLANTS 
patiently by dealing with relatively large numbers, always 
remembering that recessives when evident are always pure, at 
least as far as their own dominants are concerned. 
Systems of planting. In order to make safe and certain 
progress in improvement of plants, definite systems of planting 
must be observed. Two systems are in vogue, — the plot system 
and the row system. Each has its advocates, and each has its 
advantages for certain purposes. 
The plot system is the older. In this system the seeds of a 
given selection are planted together in a small plot of ground, 
which is labeled and numbered. In the row system each selec- 
tion is planted in a separate row, which is also labeled and 
numbered. 
Whichever system is adopted, adequate methods of number- 
ing and recording not only the ancestry of the planting but also 
the progeny or crop must be devised and rigidly adhered to ; 
indeed, much of the success of improvement in plants, which 
necessarily run into large numbers, is dependent upon the skill 
and faithfulness of the record keeper. 
Records. The exact form of the record will of course depend 
upon the particular plants and characters involved, and to some 
extent upon the system of planting adopted, whether in plots 
or in rows. For simple operations the student can devise his 
own system of records, and for more complicated cases he is 
referred to ‘‘ Principles of Breeding,” pp. 644-650, where com- 
plete illustrations are given of the method of record keeping in 
the wheat-breeding experiments at Minnesota, where the plot 
system is used, and in the corn-breeding work at Illinois, where. 
the row system is in use. 
The general principle is that every plot or row be designated 
by number, that every seed selection have also its serial number, 
and that full descriptions be recorded of all plantings. <A little 
that some of the Jersey and some of the Holstein-Friesian characters would 
blend, making anything like a pure Jersey or Holstein-Friesian forever after- 
ward impossible. 
