JOlNiaOFAGiaaiTiAllSEMCH 



Vol.. XXII Washington, D. C, November 12, 1921 ,^ No. 7 



GENETIC BEHAVIOR OF THE SPELT FORM IN CROSSES 

 BETWEEN TRITICUM SPELTA AND TRITICUM SATI- 

 VUM ' 



By Clyde E. LEighTY, Agronomist, Office of Cereal Investigations, Bureau of Plant 

 Industry, United States Department of Agriculture, and Sarkis Boshnakian, Depart- 

 ment of Plant Breeding, College of Agriculture, Cornell University 



INTRODUCTION 



In connection with genetic studies of density in the wheat spike, it 

 was noted that the appearance of dififerent specific forms in certain wheat 

 crosses introduced marked irregularities in density curves of the second 

 and following generations, and that the densities of Triticum sativum 

 Lam., T. polonicum Linn., T. spelta Linn., etc., were affected in different 

 degrees when a certain known density factor was introduced through 

 hybridization. In some instances there were partial and sometimes 

 total inhibitory effects in regard to density, depending upon the sub- 

 species and also the kind of density factor involved in the cross. 



The occurrence of these irregularities which appeared to be caused 

 by the spelt character in some crosses led to the study of the nature and 

 genetics of the species T. spelta. Although studies have been made of 

 the mode of inheritance of the spelt form in a large number of inter- 

 specific crosses, only the different modes of inheritance in crosses where 

 the parents are spelta and sativum are presented in this paper. In other 

 crosses, such as turgidum Linn. X sativum, durum. X sativum, dicoccum 

 Schr. X .yafwwm, etc., spelts invariably appear in the F2 generation. The 

 mode of inheritance of these spelt forms is complex and variable, so their 

 discussion here has been omitted. 



The plants on which these studies were made were grown, with a few 

 exceptions, on Arlington Farm, near Washington, D. C, or on the Plant 

 Introduction Station, Chico, Calif., both operated by the United States 

 Department of Agriculture. The crosses were made at the former place 

 in 1913. 



> The specific name T. sativum as used in this paper refers only to the forms T. vulgare Vill., T. compactum 

 Host., and T. capitatum Schlz. These three forms are essentially the same species, their differences being 

 merely a question of intemode length. The word wheat is frequently used as an English designation for 

 these forms, and when so used does not include such other forms as T. durum Desf . , T. polonicum, etc. 



Journal of Agriailtural Research, Vol. XXII, No. 7 



Washington, D. C. Nov. 12, 1921 



aak Key No. G-isa 



