THE INHERITANCE OF THE WEAK AWN IN 

 CERTAIN AVENA CROSSES^ 



H. H. LOVE AND A. C. FRASER 



For some time past, the writers have had under observa- 

 tion many different hybrid series of oats. Certain of 

 these otfer an excellent opportunity for a study of the 

 inheritance of awns. This paper is a preliminary report 

 aiming to set forth ideas regarding the factor differences 

 between certain types of awns, as a basis for a further 

 study of the relation between awning and other charac- 

 ters of the oat grain. 



KixDS OF Awns 

 Practically all of the wild types of oats are character- 

 ized by a very strong awn. This awn is typically long, 

 stiff, and geniculate. The basal portion of the strong 

 awn is twisted in a clockwise fashion and either black or 

 dark brown in color. Above the twist, the awn is prac- 

 tically straight until it reaches the knee, at which point it 

 turns sharply and proceeds almost at right angles to its 

 former course and usually in a different plane. The first 

 step in the modification of this type of awn seems to be 

 the loss of geniculation, together with a reduction of the 

 stiffness. Then a further straightening of the awn occurs, 

 leaving it practically straight from the ]K>int of attach- 

 ment to the tip. Such a change is acconipaniod by a loss 

 of the dark color at the base of tlu^ awn. An awn of this 

 last type is usually spoken of as the ircak <iivh. The weak 

 awn may vary greatly in length, thickness, and rigidity. 

 In some cases it becomes n mere hair-like appendage, 



1 Paper No. 62, Department of Plant Breeding, Cornell Univeraity, 

 Ithaca, N. Y. 



