104^ Inheritance in Barley 



laterals were less strongly awned than were the medians [Hexastichum 

 barleys have their medians and laterals fully awned ; intermediums have 

 fully awned medians and completely awnless, blunt-ended laterals]. 



Cross No. 14 — Haxtoni x pyramidatum — was worked out fairly com- 

 pletely. In the F^ the following proportions were found : 



Typical 6-row : Remainder of i'a = 43 : 133 

 (all awns full) . . . = 1: 3 



The " remainder " consisted of some plants exactly resembling the J^i , 

 of some with part only of their lateral florets fertile and with their 

 lateral outer paleae sharply pointed, and of some with occasional fertile 

 laterals, the lateral outer paleae being always blunt (as in the Haxtoni 

 parent). From the F3 it was clear that the " typical 6-row " of the F2 

 was homozygous, as was the F^ group which resembled Haxtoni. The 

 F2 group, whose lateral paleae were pointed, produced in ^3 all types 

 (the two parental and the pointed lateral). They were therefore hetero- 

 zygous. The variability of the shape and fertility of the lateral — 

 common in heterozygotes — made precise sorting very difficult, and the 

 proportion of Haxtoni type in F^ could not satisfactorily be proved to 

 be 1/4 (actually it was 21*1 °/„). That the Haxtoni type of F^ bore 

 some infertile laterals on certain (or all ears) of some plants, is in con- 

 formity with the fact that precisely the same thing may and often does 

 occur in pure parental Haxtoni. 



The definiteness of the 1 : 4 proportions of pure 6-row type in F^ 

 (43 plants out of an F2 of 176 plants) and the approach of the proportion 

 of Haxtoni plants in F2 to 25 7o > point to the fact that the difference 

 between the parental forms is, for lateral floret, unifactorial. 



It may therefore be stated — using the notation of § II above — that 

 the lateral floret forms (A) and (B) are allelomorphs. 



()8) Hexastichum x distichum, i.e. (A) and (F). 



The evidence of §111 shows that (A) and (F) are alleloraorphic 

 characters. 



(7) Hexastichum x decipiens, i.e. (A) and (G). 



The data given by Biffen (5) show that in the i\ a 1 : 2 : 1 ratio 

 was obtained. 



The ^3 growings afforded full confirmation of the fact that the F^ 

 contained, in addition to both the parental forms, one and only one 

 heterozygote. 



Hence (A) and (G) are allelomorphic characters. 



