REPORT OF THE CONFERENCE ON GENETICS. 35 
T. turgidum x T. vulgare (vars.). 
T. turgidum, ears dense, bearded, felted, grey, glumes keeled to the 
base; JZ. vulgare, lax, beardless or with traces of awns, smooth, red, 
glumes rounded at the base. 
F, shows dominance of lax, beardless, felting, keeling of glumes. 
The colour is not so pronounced a grey as that of the parent. 
F, shows the 3:1 ratio for the characters given above and occa- 
sionally an intensification of such characters as laxness and denseness, 
colour, and certain ill-defined straw characters. In addition, types very 
similar to 7. Spelta occur. These latter breed true to the spelt 
characters. 
Inheritance of Immunity and Susceptibility to the Attacks of Yellow Iust 
(Puccima Glumarum). 
POT CULTURES. 
Susceptible and immune parents in the same pot. In the next, grown 
under the same conditions, a number of F, plants, some of which have 
_become diseased, others which are disease-free. In the field trials F, 
was susceptible, and in the F, the ratio of susceptible to immune was 
as 3: 1. 
Inheritance of Susceptibility and Immunity to the Attacks of Yellow Rust 
(Puccinia Glumarum). 
Specimens taken from a field culture of the first generation from the 
hybrid Susceptible x Immune. 
Parents: Immune variety with dense ears, susceptible with lax ears. 
Immune and susceptible types of both varieties as they appear in 
the F,. 
On the right, plants for most part nearly killed. Left, vigorous plants 
with rust-free straw. 
Hordeum deficiens x H. Steudelu. 
The parents differ simply in colour, one being white the other black. 
F', shows dominance of the black colour. 
F,, segregation into black and white in the proportion of 3 : 1. 
No intermediate shades occur. 
H. abyssinicum x H. Steudelii. 
The chief difference between the parents is that one has broad, the 
other narrow glumes. 
The narrow type is the dominant one. 
H. nutans x H. distichon. 
The one parent has lax ears, the other dense (narrow or wide). 
The F,, has lax ears, very similar to those of H. nutans. 
F,. This generation consists of obviously lax and dense ears, 
together with a series which cannot be placed in either group. By 
matching against the parents it is impossible to separate the individuals 
c2 
