Nov. 13, 1921 Genetic Behavior of Spelt Form in Crosses 339 



classed 2, 3, and so on to 9. Class 10 includes only true wheats, the 

 forms which show absolutely no trace of the spelt characters. It must 

 be emphasized that these 10 classes are purely arbitrary, based upon 

 the appearances of the heads, and are not intended to represent any geno- 

 typic classes. The types representing these 10 classes are presented in 

 Plate 33, A. 



When the degree of inheritance of the spelt characters by a heterozy- 

 gous population is recorded on two different occasions, a variation in 

 the class frequencies naturally may be expected, but the general form 

 of the curve remains practically the same. The error which may affect 

 the conclusions rests in the decision as to whether a particular plant 

 belongs to class 9 or 10. The degree of error depends upon the cross 

 examined. 



Of the plants discussed herein, which were tested in the Fg generation, 

 there were five cases where individuals belonging in class 9 had been 

 placed in class 10 and only one case where a class 10 individual was 

 erroneously recorded as belonging to class 9. In the tables these six 

 corrections have been made. As the conclusions are based not merely 

 on the F2 individuals but upon the progeny of these, it does not seem 

 likely that this source of error could have affected the results to any 

 extent. 



The spelt parents used for making the crosses graded from i to 4 ; the 

 variety of wheat known as Gatineau ^ and herein considered as speltoid 

 in form graded from 4 to 7; and all the T. sativum parents of course 

 graded 10. As the discussions in this paper are confined only to the 

 spelt character it does not seem necessary to describe further the agrono- 

 mic and botanical characteristics of the plants used in making the crosses, 

 as these have no direct bearing on the subject. 



FAMILIES SHOWING THE PRESENCE OF ONLY ONE FACTOR FOR 



SPELTING 2 



The hybrids of the first filial generation (FJ of a spelta X sativum cross 

 are slightly intermediate in form, resembling the spelt more than the 

 sativum parent. They grade from 4 to 7, depending upon the cross. 

 They possess all the characteristics of a spelt, but the spikelets may be 

 somewhat more open and the grains may not be so firmly held within 

 the glumes. The spelt characters are so nearly completely dominant 

 that they inhibit all wheat characters. 



In the second generation a segregation is obtained where the indi- 

 viduals vary, producing forms ranging from the typical wheat form to 



' This variety originated as a cross of Red Fife 9 (T'. sativum) and Goose S {T. durum) (lo, p. 239). It 

 is a striking illustration of the spelt-like segregates which appear when these two wheat species are crossed. 

 The heads are sc much like spelt that at blooming time especially it is easily mistaken for spelt, but it 

 thrashes free and is otherwise like the common wheats. 



' For brevity, "spelting" is used throughout this paper in place of "inheritance of the spelt characters." 



