BREEDING TO INCREASE PROTEID NITROGEN. 95 



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content of a given variety of wheat raised in the same region would 

 (airy with it a corresponding improvement in its value for bread 

 making, although there might be fluctuations from year to year in 

 quality of gluten, as there is in the quantity. 



If the quality of gluten is determined by the ratio of gliadin and 

 glutenin of which it is composed, it is likely that there is some certain 

 proportion that is most desirable. Unfortunately, the investigators 

 who have taken up this subject do not by any means agree upon the 

 proper ratio. Should this be ascertained there would be ample oppor- 

 tunity for the selection of individual plants in which the proportion 

 of gliadin and glutenin would approximate the ideal. There would 

 thus be possible a much more rapid improvement in the quality of 

 wheat than can be accomplished by confining selection to an increase 

 in the gluten. 



An obstacle to the usefulness of these determinations in the whole 

 wheat appears in the announcement by Nasmith, already cited, that 

 while gliadin occurs in all portions of the endosperm, glutenin does 

 not appear in the aleurone cells. That being the case, it is difficult to 

 believe that any given ratio between these constituents in the whole 

 wheat could be taken as the one most desirable. The ratio in the 

 gluten alone may, however, have an important influence on its 

 quality, and a certain definite proportion of each may produce an 

 ideal gluten. 



In the light of the present knowledge on the subject, a mechanical 

 determination of gluten would seem to be most useful, if it can be 

 made with such small quantities of wheat as are obtained from 

 single plants, while determinations of gliadin and glutenin in the 

 gluten would afford a means of judging of its quality. 



SOME RESULTS OF BREEDING TO INCREASE THE CONTENT OF 

 PROTEID NITROGEN. 



Selected plants have been grown on a large scale for two years. 

 From these results it is very apparent that a high percentage of 

 nitrogen and the qualities that go with it are transmissible from one 

 generation to another. 



In Table 25 are analyses of the plants of the crop of 1902, grouped 

 according to their proteid nitrogen content into classes of from 1 to 2 

 per cent, 2 to 2.5 per cent, and increasing by 0.5 per cent up to 4.5 

 per cent and above. Opposite the plant number of each plant of the 

 crop of 1902 are stated its percentage of proteid nitrogen and weight 

 of proteid nitrogen in kernels. On the same line are the plant 

 numbers for the entire progeny in 1903, and following these are the 

 percentage of proteid nitrogen, weight- of prote-id nitrogen per average 

 kernel, and average weight of kernel for all of these progeny. 



The averages for each group are given in Table 26. 



