448 TRANSMISSION 



upon characters other than those under special consideration. 

 Such a critical study develops the fact that these four strains 

 differing in protein and in oil content have developed also into 

 four distinct strains regarding the purely physical characters, 

 length, circumference, etc. 



1. High and loiv protein. The ear of the former is the 

 shorter (column i), and the smaller standard deviation and co- 

 efficient of variability show it to be less variable as to length 

 (columns 2 and 3). It is also smaller in circumference (col- 

 umn 4), with a less number of rows (column 7), and lighter in 

 weight (column 10). It is also less variable in every respect, 

 both relatively (columns 2, 5, 8, and n) and absolutely (col- 

 umns 3, 6, 9, and 12). 



2. High and low oil. In the same manner we learn that the 

 high-oil ear is a shorter and a smaller ear than the low-oil, but 

 that it is more variable as to length and less variable as to 

 circumference (columns i to 6). The low-oil ear is rapidly becom- 

 ing a twelve-rowed variety, with a lower deviation than any 

 other (column 8). It is the heaviest, though not the longest, of 

 the four selected strains. 



3. The four selected strains. Of these four strains developed 

 from the same original stock, the low-protein ear is the longest 

 and the high-oil the shortest. The high-oil is also the most 

 variable as to length (column 3). 



The low-oil is the largest and the high-protein is the smallest 

 in circumference. The latter is also the least variable and the 

 low-protein is the most variable as to circumference. 



The high-oil corn has the largest number of rows, with the 

 lowest variability, and the low-oil the fewest rows, with the 

 least standard deviation but the greatest coefficient of variability. 



The low-oil is the heaviest and the high-protein the lightest 

 ear, but the low-protein is the most variable as to weight. 



It will be noted that these differences are the natural results of 

 selecting, not for these particular characters, but for chemical 

 content. They are therefore the indirect effects of selection, 

 and bring up again the whole subject of correlation, which will 

 be treated further in a later chapter. 



