5 go Journal of Agricultural Research vo1.xix.no.ii 



SUMMARY 



H. intermedium is a form of barley in which the awnless lateral florets 

 exhibit a fertility greater than that found in the 2-ro\ved and less than 

 that occurring in the 6-rowed barleys. 



The occurrence of this form as a homozygote has been questioned 

 frequently. 



H. intermedium forms which are stable under all conditions of culture 

 have been isolated from numerous crosses reported in this paper. This 

 form appears to be genetically as distinct as either H. vulgare or H. dis- 

 iichon. 



A 2-factor hypothesis for fertility in the lateral florets is suggested. 

 On the presence-and-absence hypothesis the 6-rowed barleys are sup- 

 posed to be homozygous for the presence of the epistatic factor, the 

 intermedium to be homozygous for the presence of the hypostatic factor 

 and for absence of the epistatic factor, and the Svanhals to be homozygous 

 for the absence of both factors. 



According to the hypothesis, there are two types of 6-rowed barleys. 

 The Manchuria parent is supposed to be homozygous for the presence of 

 both factors, while certain regressive 6-rowed segregates are thought to 

 be homozygous for the presence of the epistatic factor and for the absence 

 of the hypostatic factor. 



There is evidence suggestive of a third factor which affects the vigor 

 of the lateral florets and their percentage of fertility. 



LITERATURE CITED 

 (i) Biffin, R. H. 



1907. THE HYBRIDIZATION OF BARLEYS. In JoUf. Agr. Sci., V. 2, pt. 2, p. 183- 



206. 



(2) Harlan, Harry V. 



1918. THE identification OF VARIETIES OF BARLEY. U. S. Dept. AgT. Bul. 



622, 32 p., 4 pi. Literature cited, p. 31-32. 



(3) H[axton], J[ohn]. 



1851. BARLEY, /n Morton, John C, ed. Cyclopaedia of Agriculture . . . v. i, 

 p. 1 76-19 1. Glasgow, Edinburgh, London. 



Article is signed "J. H." and is credited by Komicke to Haxton. See following 

 reference, p. 173. 



(4) KORNiCKE, Friedr, 



1885. DIE ARTEN und varietaten des getreides. 470 p., lo pi. Berlin. 

 (Komicke, Friedr., and Werner, Hugo. Handbuch des Getreidebaues. 



V.I.) 



(5) 



1908. DIE ENTSTEHUNG UND DAS VERHALTEN NEUER GETREIDEVARIETATEN. 



Hrsg. von M. Kornicke. In Arch. Biontol., Bd. 2, Heft 2, p. 389-437. 



(6) RiMPAU, Wilhelm. 



1891. kreuzungsprodukte landwirtschaftlicher kltlturpflanzen. 



In Landw. Jahrb., Bd. 20, p. 335-371- 



(7) 



1892. die genetische entwickelung der verschiedener FORMEN UNSERER 



Saatgerste. In Landw. Jahrb., Bd. 21, p. 699-702. 



