BREEDING TO INCREASE PROTEID NITROGEN. 



99 



In Table 26 the averages for each group are stated. This table is 

 designed to show whether there has been a tendency for plants of a 

 certain class to reproduce the qualities pertaining to that class, or 

 whether these are lost in the offspring. 



It is unfortunate that there are not a greater number of analyses of 

 plants of medium and of low nitrogen content. The plants selected 

 for reproduction in 1903 were largely those of high nitrogen content, 

 and, consequently, comparatively few analyses of the low nitrogen 

 and medium nitrogen plants of 1903 are at hand. 



Table 25 shows that in the main there is a tendency for each class 

 of plants to reproduce in the same relation to the other classes, but 

 that there is less difference between the extreme classes in the off- 

 spring than in the parent plants. In other words, while all plants 

 tend to reproduce their own qualities, those plants varying widely 

 from the average produce, in general, offspring varying from the 

 average less widely than did the parents. Although this is a rule, its 

 application to the individual is not universal. Certain plants may be 

 found whose tendency to variation extends through both generations. 

 There is also wide variation between certain plants of the same 

 parent. For instance, the plants numbered from 21205 to 21212, all 

 of which come from the same parent, vary from 2.16 to 5.23 per cent 

 in proteid nitrogen content, while plants 69805 and 69806 vary from 

 5.82 to 1.66 per cent in this constituent." 



It would seem, therefore, entirely reasonable to believe that a very 

 considerable increase in the proteid nitrogen content of wheat may be 

 effected by careful and continuous reproduction from plants of high 

 proteid nitrogen content. 



Table 27 contains the analyses of plants raised in 1902 and their 

 progeny raised in 1903, arranged according to the number of grams of 

 proteid nitrogen contained in the average kernel of the former. 



TABLE 27. Analyses showing transmission of proteid nitrogen in average kernel. 



Table 25 represents the properties of each plant grown in 1903 arranged according to 

 immediate families. For instance, plants numbered 17305-17308 are all the offspring of 

 the same plant grown in 1902. The parent bears the number 17301. This is the system 

 of records devised by Prof. W. M. Hays, formerly of the University of Minnesota. 



