ARTIFICIAL POLLINATING 29 



Rock with the hope of securing a type suited to some particular 

 purpose which the breeder has in view, as a strain particularly 

 suited to a special meat market. Pop corn will cross with sweet 

 corn; a white variety of corn may be crossed with a yellow variety* 

 The offspring from such crossing may be called hybrids. 



The effect of crossing extreme types, as when the oxeye 

 daisy is crossed with a chrysanthemum with very different charac- 

 teristics, is to cause extreme variations in the offspring and future 

 generations. The parental types are said to be v broken. When 

 extreme variations are thus started the breeder is able to make 

 selections which may more nearly suit the ideals for which he is 



FIG. 21. Methods of wheat breeding. The stamens must be removed before natural 

 pollination takes place. After artificially pollinating the flowers, the operator covers the 

 head of wheat with a bag and labels it. (U. S. D. A.) 



striving. It was in this way that the modern chrysanthemum 

 was produced (Fig. 19). 



The crossing may be within closer relationship and may have as 

 its purpose the blending of characteristics of the parents, and an 

 effort to establish or fix one characteristic and cause others to depart. 



Artificial Pollinating. Among plants, crossing is accomplished 

 through artificial pollinating of the flowers. The pollen from one 

 parent may be placed upon the stigma surface of the pistil in the 

 other with successful results. This is done by careful hand manipu- 

 lation. The stamens must be removed to prevent other pollen 

 from reaching the pistil (Fig. 20). Then the flower must be pro- 

 tected until the stamen surface is mature enough to receive pollen. 

 Then pollen from the desired parent may be brought by means of 

 a very fine, soft brush, or feather, and carefully dusted upon the 

 stigma surface. Again this flower must be covered to keep away 

 all other pollen. 



