HERITABLE CHARACERS OF MAIZE: 



IX. CRINKLY LEAF' 



R. A. Emerson 

 College of Agriculture, Cornell University, Ithaca, N. Y. 



IN 1910a strain of dent corn obtained 

 at the National Corn Exposition 

 held at Omaha was crossed with a 

 strain of flint corn obtained from the 

 Department of Agronomy of the Univ- 

 ersity of Nebraska. The Fi plants of 

 this cross were normal and no ab- 

 normalities had been observed in the 

 parent strains. But since the latter 

 had not been subjected to self-pollina- 

 tion, there is no assurance that one or 

 ■other of them did not have in it the 

 ■character to be described here. In the 

 F2 generation of this cross there 

 occurred a type of plant that has later 

 been called "crinkly." 



Crinkly is a semi-dwarf type of plant, 

 usually about two-thirds the height of 

 normal plants of the same cultures 

 (Fig. 24). The tassels of crinkly are 

 relatively short and compact and not 

 infrequently bear numerous seeds. 

 Sometimes only a few such seeds 

 develop but often a part of the central 

 spike of the tassel is more or less ear- 

 like. 



The upper leaf blades of crinkly are 

 relatively short and broad, are usually 

 much crinkled and often have promi- 

 nent lobes near the base (Fig. 25). All 

 of these characteristics are so variable, 

 however, that some plants classed as 

 crinkly do not show prominently one 

 or other of them. Considering all 

 these leaf characters together with 

 stature and form of tassel, it is usually 

 easily possible to separate crinkly from 

 normal plants, but occasionally the 

 separation is somewhat difficult. 



In stocks of crinkly in which the 

 characters noted above are developed 

 to an extreme degree the tassels ordin- 

 arily have great difficulty in pushing 

 out from the more or less rolled upper 

 leaves (Fig. 26). It is sometimes 



necessary to slit the upper leaves to 

 release the tassels and allow the pollen 

 to be shed normally. 



The ears of crinkly are usually some- 

 what smaller than those of normal 

 plants but are not otherwise materially 

 diflterent. 



INHERITANCE OF CRINKLY 



Crosses of crinkly with normal have 

 invariably given normal Fi plants. 

 Self-pollinated Fi plants produced 717 

 Fa's of which 544 were normal and 173 

 crinkly, a deviation of 6.3 I 7.8 from 

 the 3 :1 ratio. From backcrosses of Fi 

 normals with crinkly a total of 3,567 

 plants resulted. Of these 1,850 were 

 normal and 1,717 crinkly. This is a 

 deviation of 66 . 5 I 20.1 from equal- 

 ity. So great a deviation could be 

 expected by chance alone only about 

 once in 38 trials. In some of the back- 

 cross progenies the crinkly plants were 

 not so easily separated from normals 

 as in others. It seems likely that this 

 difficulty in identifying crinkly in 

 some cultures may explain in part the 

 deficiency of that type, but it is possi- 

 ble also that crinkly does not survive 

 under crowded field conditions as well 

 as normal plants. Most dwarf and 

 semi-dwarf types of maize, such as 

 dwarf, anther ear, tassel ear, etc., 

 almost always are deficient in field 

 cultures, particularly when grown 

 under unfavorable conditions, and 

 there is no apparent reason to expect 

 crinkly to behave very differently from 

 some of these other types. 



Self-pollinated crinkly plants have 

 invariably produced nothing but 

 crinkly progeny. Something over one 

 hundred crinkly plants have been ob- 

 served in such cultures. 



1 Paper No. 92, Department of Plant Breeding, Cornell University, Ithaca, New York. 



267 



