44 



THE DEPARTMENT OF AGRICULTURE. 



VARIETIES. 



Standardization of Varieties. If good markets are to be obtained it is absolutely 

 essential that standard varieties be grown. Many times good markets are lost wbich 

 would otherwise have been obtainable if a district had been growing a standard 

 variety. 



Oftentimes it is difficult to get a car-load of standard potatoes from a district 

 because so many varieties are being grown, whereas if all were growing the same 

 variety little difficulty would ensue. The importance of standardization cannot be 

 overemphasized. 



Production of Neiv Varieties by Cross-fertilization. In the improvement of field 

 crops two general methods are followed: (1) Selection; (2) artificial cross-fertiliza- 



Fig. 37. A good display of Gold Coin potatoes (original). 



tion. The method which is more simple to understand and undoubtedly within the 

 reach of every potato-grower is " selection." This implies the improvement of the 

 variety being grown by a careful selection of those tubers which are of good type 

 and quality, sound and free from disease. Since selection has been dealt with in 

 another part of this bulletin, only artificial cross-fertilization or hybridization will 

 be discussed here. 



Fertilization implies sexual reproduction. When the ovules of a flower are 

 fertilized by pollen from the anthers of the same flower, or by pollen from another 

 flower on the same plant, or from pollen produced from cuttings, this is called 

 self-fertilization. 



Cross-fertilization takes place when the ovules of a flower are fertilized by 

 pollen from another flower on a distinct plant of the same species. Some plants, 



