286 



Plant-Breeding 



Flowers that bear no stamens, as the pistillate flowers 

 of squashes, strawberries, and many other plants, of 

 course do not require emasculating. They should be 

 tied up while in bud, however, to prevent the access of any 

 foreign pollen. Indian corn is a case in point. The 

 pistillate flowers are on the ear, each 

 kernel of corn representing a single 

 flower. The silks are the stigmas. 

 If it is desired to cross corn, there- 

 fore, the ear should be covered before 

 any silks are protruded, and the 

 pollen should be applied some days 

 later, when the silks are fully grown. 

 The staminate or male flowers are 

 in the tassel. 



The pollen should be derived from 

 a flower which has also been pro- 

 tected from wind and insects, be- 

 cause foreign pollen may have been 

 dropped upon an anther by an insect 

 visitor, and it may be unknowingly 

 transferred by the operator. The 

 pollen-bearing parent needs no oper- 

 ation, of course, but the flower should have been tied up in 

 a bag when it was in bud. The pollen is best obtained by 

 picking off a ripe anther and crushing it upon the thumb- 

 nail. Then it is transferred to the stigma by a tiny scalpel 

 made by hammering out the small end of a pin, as shown, 

 full size, at the left in Fig. 91. The stigma should be 

 entirely covered with the pollen, if possible. It is often 

 advised to use a camel's-hair brush to transfer pollen. 



FIG. 93. Bag for cov- 

 ering the flowers. 



