CULTURE OF WHEAT 



89 



In the yield has been obtained. In a number of experiments the 

 influence of the number of seeds per acre has not been eliminated. 

 If the grains of the spikelets of wheat be designated by 

 numbers according to the distance from the spikelet, it has been 

 found that grains occupying the second place are the heaviest ; 

 that those in the first and the third place are about equal in 

 weight; while grains in the fourth and the fifth place, if any, are 

 still lighter. It is also found that of grains occupying the same 

 relative position, those on the lower half of the spike are the larger. 

 The following table gives results with two varieties of wheat : ^ 



"it would thus appear that small and large grains come from the 

 same plant, var}dng in size because of their position, as do the 

 grains of maize on the ear. If the plant and not the individual 

 seed is the unit of reproduction, small seeds from productive 

 plants will be better than large seeds from unproductive plants, 

 provided productivity is due to heredity and not to environment, 

 except in so far as large seeds may give the plant a more vigor- 

 ous start in life. (43) It has been shown, however, that on an 

 average, the larger spikes contain the larger grains, so that in 

 selecting the larger grains the larger number of them would 

 come from the larger spikes.^ 



134. Treatment of Seed. — Before sowing, the seed should 

 be carefully screened in a fanning mill, or wheat grader, or 



1 Kurt Rumker: Jour, of Landw. 38 (1890), p. 309. 

 a Seed Wheat, pp. 1-60: Sidney, 1903. 



