POTATOES 389 



known save, possibly, the characteristics of the parent bearing the 

 seed. When the seed is the result of definite crossing, two ele- 

 ments are known, and if the origin of the two parents used is 

 known, a still greater interest attaches to the work, for the progeny 

 will give a clew to the relative strength of the two parents and their 

 prepotency. Such knowledge is of the greatest value to the breeder 

 in securing the combinations necessary to produce the desired 

 results. The more extensive the information at hand as to the 

 behavior of the progeny of definite crosses, the more exact will 

 become the work of the breeder. 



In the work of cross-pollination the mere transfer of pollen is 

 not sufficient. The flower to be used as the seed parent must be 

 emasculated before its pollen has developed ; that is, the stamens 

 must be removed, and the flower protected by means of a small 

 manila bag until the stigma has reached maturity, at which time it 

 will be ready to receive the pollen of the flower with which it is to 

 be crossed. This flower, also, should be carefully covered to exclude 

 insects and thus insure it against pollen from other flowers. After 

 the emasculated flower has been pollinated, it should again be cov- 

 ered to protect it as before, the cover being allowed to remain until 

 the seed balls have ripened so as to protect them against loss. 

 Careful records of the plants used should be made so that the char- 

 acter of the progeny can be determined. The behavior of the second- 

 generation cross of the potato is not known. It is possible that it 

 may hold as much of interest and value as the second-generation 

 hybrids of other plants, which has proved to be the generation in 

 which the splitting up the result of the influence of the two 

 parents takes place, thus explaining the greater achievements 

 met with in recent years by hybridization. 



Growing the plants. After having secured a satisfactory seed 

 supply, the next step is the growing of the seedlings. This is the 

 point at which many propagators fail. In order to attain satisfac- 

 tory results the seed of the potato should be planted at the same 

 time and treated in the same way as the seed of early tomatoes. 



In the latitude of New York City the seed should be sown in a 

 gree'nhouse or hotbed not later than March 15. As soon as large 

 enough the young seedlings should be pricked out in flats or boxes 

 and, if possible, shifted to pots before being placed in the open. 



