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 



FIG. 138. Spreading and erect pure lines of Gypsy wheat, 1907. (After Williams, Ohio 



A.E.S.) 



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 

 22 



