SELECTION 337 
single head selection made by Roberts in 1906. Altogether he made 557 
selections from nearly 200 different varieties; but nearly 415 of these were 
discarded within 2 years. 
The Plant-to-row Method.—Single plant selections are usually grown 
in garden rows, each row from a different plant. Final selection of the 
individual plants should be preceded by field observations, noting habit, 
vigor, disease resistance, season of bloom, time of maturity, productivity, 
etc. Each of these plants must be harvested separately and careful 
Fic. 138.— Spreading and erect pure lines of Gypsy wheat, 1907. (After Williams, Ohio 
A.E.S8.) 
records should be made concerning yield and other important characters. 
It is on the basis of the field observations and the data from the harvested 
plants that a further selection must be made. From each of the plants 
finally selected sufficient seed is taken for a row of about 25 plants. The 
rows should be evenly placed and plants should be equidistant in the row. 
By subjecting these rows to severe selection the future work may be 
considerably reduced. Hence careful notes should be taken throughout 
the season and at harvesting time. Of several hundred rows only a 
few may be found good enough to be continued. The third year the 
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