CLASSIFICATION OF AMERICAN WHEAT VARIETIES. 41 



The texture classes used here are two — kernels soft to semihard 

 and kernels semihard to hard. Here, as with size, overlapping class 

 limits were found to be necessary. In general, all wheat varieties can 

 be classed readily in one or the other of these two groupings. In de- 

 scribing specific samples and in individual description of varieties, 

 three classes are used separately, as soft, semihard, and hard. A soft 

 wheat is one which, when normally developed, has an endosperm en- 

 tirely soft, mealy, or starchy. A hard kernel, when normally devel- 

 oped, has a corneous, horny, or vitreous endosperm throughout. A 

 semihard kernel has an endosperm which is intermediate between the 

 two. Cross sections of kernels showing differences in texture in both 

 normal and yellow-berry kernels are shown in Plate VII, Figure 2. 

 The upper series of kernels shows normal development and the 

 lower series the yellow-berry condition. In Figure 2 a, (1) and 

 (2) represent different degrees of softness and (3) the semihard con- 



SHORT TOMIDLONS m.DLONG TO LONG 

 ^ 6.5 TO IO mm. 



SHORT MIDLONG LONG 



4T0 6mm. 6T0 8mm. 8TO lOmm. 



Fig. 11. — Diagram showing measurements of kernel lengths : 

 Above, major characters ; below, minor characters. (Enlarged 

 10 diameters.) 



dition in the soft class. In Figure 2, 6, (4) shows the semihard condi- 

 tion and (5) and (6) different degrees of hardness. 



The species Triticum durum was so named by Desfontaines (79) 

 because of the hardness of the kernels. Metzger (US) divided the 

 white-kerneled wheats into two groups on the basis of texture, the 

 starchy ones being considered as yellow. Koernicke and Werner (133) 

 described the wheat kernels of different varieties as being entirely 

 mealy, nearly entirely mealy, mostly mealy, partly mealy, partly 

 glassy, mostly glassy, nearly entirely glassy, and entirely glassy. The 

 texture of the same variety varied in different seasons. These authors, 

 as well as Eriksson (88), Fruwirth (92), and Howard and Howard 

 (121, p. 232), conclude that kernel texture is useless as a varietal 

 character and that it depends on environment. Hayes, Bailey, Amy, 

 and Olson (105) suggest the terms corneous, subcorneous, substarchy, 

 and starchy for describing the texture of the wheat kernel. The 

 writers have concluded that because of the variability in texture 

 under different environments one can separate varieties of wheat 

 accurately into only two classes and fairly accurately into three 

 classes. Soft-kerneled varieties grown under very dry conditions 

 will sometimes become brittle and slightly subcorneous. When hard- 

 kerneled varieties are grown under humid conditions or in soil de- 

 ficient in nitrogen they sometimes become starchy, semistarchy, or 



