142 maine agricultural experiment station. i916. 



Tabee 13. 

 Germination Test of Pure Lines. 



Line Number. 



Number of Germinated 

 Kernels. 



Percentage of 

 germinated 





Series I. 



Series II. 



kernels. 



Maine 247 



199 'ZZ 



200 



199 



200 



200 



19S 



197 



198 



198 



196 



199 



192 



200 

 199 

 199 

 198 

 198 

 199 

 200 

 199 

 197 

 198 

 194 

 192 



99.8 



Maine 351 



99.8 



Maine 340 



99.5 



Maine 286 



99.5 



Maine 336 



99.5 



Maine 346 



99.3 



Maine 281 



99.3 



Maine 357 



99.3 



Maine 307 



98.8 



Maine 230 



98.5 



Maine 355 



98.3 



Maine 337 



96.0 









198.0 



197.4 



98.9 







The preceding description of these pure lines has shown very 

 clearly that there are no marked morphological differences be- 

 tween these pure lines and their respective parent varieties. 

 In the discussion of the majority of the characters, e. g., stool- 

 ing, type of head and of grain, it has been necessary to deal 

 with groups of the pure lines corresponding with their parent 

 varieties. On the other hand, there is a large amount of evi- 

 dence which indicates that in such characters as yielding ability 

 and strength of straw these pure lines are distinctly superior 

 to their parent varieties. 



The modern view of the hereditary processes indicates that 

 separate characters are inherited as units or as groups of units. 

 It is, therefore, conceivable that at some time in the history of 

 the parent varieties, spontaneous germinal changes occurred 

 which affected the hereditary yielding ability of a certain 

 plant. Such changes might or might not be accompanied 

 by changes in one or more morphological characters. Further, 

 such a spontaneous germinal change might result in either an 

 increase or a decrease in the yielding ability. In the process of 

 selection and elimination as outlined in this paper naturally only 

 the variations in the direction of an increase would be pre- 

 served. 



That variations do occur which tend to yield less than the 

 parent varieties is indicated by the so-called "running out" of 

 varieties. A variety which has been grown for many years 

 without any attempt at improvement often shows a large num- 



