GRADING SEED WHEAT 



149 



sonable to expect better grain in the harvested crop than is 

 sown. Wheat grown continuously in one community is 

 often said to run out, and frequently the practice of chang- 

 ing seed grain every few years is followed. This is not the 

 best practice, for it has been shown beyond any question of 

 doubt that if the home-grown grain is carefully graded each 

 year and the best used for seed, it will not run out, but may 

 be gradually improved. 



On the general farm, there is not sufficient time to permit 

 the careful breeding and selection of grain as is practiced by 



careful plant breeders ; 

 but it is entirely practical 

 to select a small propor- 

 tion of the best grain by 

 running a considerable 

 quantity of it through a 

 common fanning mill, 

 and in this way selecting 

 the heaviest and plumpest 

 kernels. 



187. Fanning Mill 

 Selection. Fanning mills 

 separate grain by size and 

 shape of kernel, and by 

 weight of kernel. In some makes of mills one of these 

 methods is employed, and in others both are used. The 

 mill which separates by only one of these means can not 

 do as satisfactory work as one in which both are used. 

 With a mill using both methods, the heavy and light kernels 

 of wheat can be separated; the heavy kernels can then be 

 run over a screen of the proper size so that the smaller ones 

 will be taken out and only the larger ones left for seed. In 

 this way the very best seed grain can be obtained. 



Fig. 48. Diagram of fanning mill, 

 showing a method of grading seed grain. 

 The wind blast from the fan at the right 

 blows the chaff and light grain out at the 

 left; the heavier grain falls on screen 3, 

 through which the smaller kernels fall, 

 leaving the large, heavy kernels for seed. 



