INHERITANCE— IMPROVEMENT BY BREEDING 205 



East and Hayes find that two distinct kinds of irregularity 

 of row numbers occur : one a physiological fluctuation which 

 is not inherited, and one a definitely inherited character, or 

 possibly a set of characters. 



" The non-inherited fluctuations are always present, while 

 the inherited irregularity may be present or absent. The latter 

 kind has been isolated in several varieties [breeds], the most con- 

 spicuous being the Country Gentleman [sweet] corn. . . . Since 

 the inherited irregularity can only be distinguished from the 

 fluctuation by breeding, and then with difficulty owing to the 

 obscuring effect of the latter, it is difficult to come to any 

 conclusion regarding the method of its transmission when 

 dealing with mixed strains. It could undoubtedly be deter- 

 mined by careful work with a cross of which Country Gentle- 

 man formed one of the parents. We have not made such a 

 cross, but observations of large commercial cultures of Country 

 Gentleman lead us to believe that irregularity is a Mendelian 

 dominant, although it may not act as a simple monohybrid. 

 . . . The one fact that stands out clearly is that if the per- 

 centage of irregular ears increases much over 4 per cent in a 

 commercial progeny row culture, the whole culture must be dis- 

 carded to eliminate the undesirable 'blood'." 



The results obtained by them, to the F 3 generation, are 

 shown in Table XLII following: — 



CHAP. 

 V. 



Table XLII. 

 INHERITANCE OF ROWS IN A MAIZE CROSS. 



