THE BREEDING OF CORN 197 



serve as a check against the inequalities in the productive- 

 ness of the soil comprising the breeding plot. 



Where isolation is impossible, the breeding plot should 

 be surrounded by three or four rows planted with seed from 

 the selected ears which remain after the breeding plot has 

 been planted. Conditions will be made still more ideal 

 if this breeding plot is situated in the midst of a large 

 field of a selected strain of corn of the same variety. This 

 latter precaution will be impossible during the first season 

 of the breeding, but from the third year it will always be 

 practicable. Such an arrangement prevents the seed 

 plot from being contaminated by pollen from unbred 

 sorts. 



241. Cultivation. Ordinary cultivation should be 

 given the breeding plot, care being exercised to see that 

 all rows are treated alike. It must be remembered that 

 the results of pedigree selection will be meaningless unless 

 uniform conditions are maintained throughout the entire" 

 breeding plot. 



242. Detasseling. In breeding corn by pedigree 

 selection, the conditions are such as to favor inbreeding 

 and close breeding, either of which is likely to decrease 

 the vigor of the plant. To avoid this the practice of 

 detasseling every other row or the alternate half of every 

 row and saving seed only from the best detasseled rows 

 is recommended. The method of detasseling consists 

 merely in pulling the tassels out before pollen is produced, 

 and bears no injury to the plant. The field must be gone 

 over at least three times. In addition to pulling the tassels 

 from the plants in the rows that are to furnish the seed, it 

 is important that all inferior plants in the sire rows be 

 detasseled. The methods employing the principle of 

 detasseling to avoid jnbreeding vary somewhat with 



