120 



for selecting plants with reference to the quality of the wheat itself. :\Iy 

 object, then, in starting this work was to find some method of sampling the 

 plant that would give an indication of its quality. 



In my work a number of plants of Turkish Ited wheat were analyzed, each 

 bead of the plant being harvested separately, and the analysis being made 

 separately of each head, all kernels of each head being used. The data 

 obtained show that there is (piite a difference in the proteid content of these 

 various heads, and that it would not l)e safe to take the analysis of any one 

 spike as repre.senting the composition of the i)lant on which it grew. 



Analyses were also made of groups of spikes on the same plant — that is, 

 supposing that a i)lant l)ore ten spikes, we would take five of those in one 

 group and five in the other group, then shell out all of the kernels in each 

 group and' analyze eacii group separately. In other words, we made an 

 analysis of half of the kernels on half of the heads of the plant. The results 

 attained in this way were very mucli closer than the results of analyzing the 

 separate heads. Thus by taking half the number of heads of the plant and 

 analyzing them we got a fairly good sample of the whole plant. Separate 

 analyses made of the two rows of kernels showed small difference in the total 

 nitrogen and proteid content of the samples. 



In carrying on our work we have adopted the practice of sampling etxch 

 bead by taking one row of spikelets as a sample for analysis and the other 

 row of spikelets as a sample for planting; then by sampling each head on the 

 plant we get what we consider to be a good average sample of the plant for 

 analysis. 



The proteid nitrogen content of 800 spikes of Turkish Red wheat selected 

 in the field in 1902 \\ ith special pains to secure heads that were thoroughly 

 matured and free from disease was determined and the seed planted. From 

 the crop thus obtained selections were made and kernels from entire plants 

 were .sampled and analyzed. The minimum content of proteids, that is, 

 proteid nitrogen multiplied by 5.7, was G.38 ; the maximum, 28.21 ; showing a 

 very large range and indicating the possibility of increasing very largely the 

 nitrogen content by selection. Analyses of 351 plants grown from the above 

 in 1903 showed a minimum proteid content of 5.84 per cent and a maximum of 

 33.34 per cent. 



When the analyses of the original 800 spikes were made determinations were 

 also made of specific gravity of the kernels in a considerable number of the 

 heads. The weight of the kernels on the low nitrogen content heads was found 

 to be somewhat larger than it was on those of high nitrogen content. While 

 the decrease was not regular, there was a slight tendency for the yield to 

 decrease as the nitrogen content increased. The weight of the average kernel 

 also agreed with the weight of the kernels on the spike, there being m the 

 main a slight decrease in the weight of the average kernel as the content of 

 jn-oteid nitrogen increased. The number of kernels on the spike did not vary 

 particularly. The volume occupied by the kernels decreased, or bad a slight 

 tendency to decrease, as the proteid nitrogen content increased. The specific 

 gravity decreased regularly as the content of nitrogen increased. The proteid 

 nitrogen in all the kernels increased as the percentage increased, and the proteid 

 iiitrogen in the average kernel increased as the percentage increased; so that, in 

 spite of the fact that the kernels became somewhat smaller and lighter, the 

 total production of nitrogen increased as the percentage increased. In other 

 words, a selection based on increase in percentage of nitrogen would increase at 

 the same time the total production of nitrogen. 



Similar figures for the nitrogen content of all of the heads of the plant of the 

 crop of 1903, instead of one head as in 1902, also showed that the number of 

 kernels decreased slightly as the percentage of nitrogen increased; the weight 

 of the kernels also decreased as the percentage of nitrogen increased ; the weight 

 of the average kernel seemed to vary more than it did l)efore, but the tendency 

 was for the weight to decrease with an increase in the percentage of proteid 

 nitrogen ; the grams of proteid nitrogen in the kernels increased in the main 

 as the percentage increased ; and the grams of proteid nitrogen in the average 

 kernel increased as the pei'centage increased. The increase in the average 

 kernel was very large. 



We discarded all kernels that were not fidly developed because it is well 

 understood that kernels that had not fully rii)ened would have a higher nitrogen 

 content than those that had. 



In the crop of 1903 we also determined gliadin and glutenin in most of the 

 plants. Our object in doing this was not very definite. Of course we were 



