Variation and Heredity 



491 



1. A study of the methods and manipulation of crossing, con- 

 sulting such references as- 



BAILEY, L. H. Plant Breeding. Pp. 344-358. 

 OLIVER. Bureau of Plant Industry. Bui. 167 : 39 pp. 



'-* 



* T> 



FIG. 141. Dahlia flowers after depollination by means of a stream of 

 water. [Photograph from Bureau Plant Industry.] 



2. The results of crossing. In the latter case parents, to- 

 gether with first and second generation crosses, should be com- 

 pared with respect to characters, following the suggestions in 

 sections 294-297. Fresh material is most desirable, but if it 

 may not be had at the time desired, alcoholic or dried material 

 will serve adequate!} 7 for the study of many characters. 



REFERENCES 



BAILEY, L. H. Plant Breeding. 4th Ed. 463 pp., 20 figs., 1907. 

 BATESOX, W. The Progress of Genetics since the Rediscovery 



