FARMERS' METHODS OF PRODUCING PURE SEEDS 287 

 DIAGRAM OF METHOD OP CONTROLLING FLAX WILT BY SELECTION 



If wilt resistant seed is not available 

 produce it by selecting plants which are 

 resistant under wilt conditions; three years 

 of continuous selection will accomplish this. 



Field 



IMPROVED CORN SEED 



The determination of the better variety of corn to grow is not 

 difficult. The farmer can obtain reliable advice from the local 

 county agent or by consulting the nearest experiment station. 

 The introduction of new varieties of corn from other states before 

 they have been tested for the climatic conditions in question is a 

 very undesirable practice and as a rule a cause of much annual 

 loss to the corn grower. The problem with corn is somewhat 

 different from that with the self-fertilized crops. Corn is cross- 

 fertilized, therefore constant inherited variability is the rule. 

 When a variety is introduced from another locality it undergoes 

 a process of selection which may markedly change its characters. 

 Selection in a pedigreed line of wheat, on the contrary, does not 

 change its characters and serves only to keep the variety in the 

 same state of purity by artificially removing any possible mix- 

 tures which may occur. This brief discussion will probably 

 serve to show that seed selection on the farm is a very impor- 

 tant practice for the corn grower, unless there is a local grower 

 of high grade seed. 



The corn seed grower faces another difficulty which the small- 

 grain seed producer does not have to consider. With small 

 grains barley, oats, and wheat purity for all characters is the 

 general rule. This has led the corn breeder also to attempt 

 to obtain purity of type. Carefully controlled investigations 

 have served to show a possible fallacy in this practice. The 



