Oct. 22 , 1917 
Inheritance Studies in Pisum 
177 
LINKAGE IN PISUM 
In Table IV the available data on linkage of factors in Pisum are given. 
As in Table III, only totals are listed, the detailed results from which the 
totals were compiled being given in the appendix, the tables being num¬ 
bered to correspond with the linked factor groups in Table IV. Linked 
group 24 in Table IV is based on the writer's own interpretation of 
Vilmorin’s (1911) data from F 2 hybrid populations and F 3 progeny from 
heterozygotes similar to the F r The deficiency of EA individuals is, as 
previously stated, probably due to insufficient ability to resist disease. 
At least, that is the writer’s own experience with emerald varieties. The 
calculation of crossover to non-crossover gametes is based on Castle’s 
table (1916). 
Group 25 is based on the studies of Lock (1905), Tschermak (1911), 
and Hoshino (1915), supplemented by the writer’s own studies, though 
none of his own data are incorporated. The figures and interpretation 
are taken from Hoshino’s paper. As previously stated, factors A, C, 
E, (Gc), and are absolutely coupled and most simply interpreted as 
expressions of A, instead of as five distinct factors, as held by Tscher¬ 
mak and others. Group 26 is based on the data and the interpretation 
of Vilmorin and Bateson (1911), and Pellew (1913), though the discovery 
was first made by Vilmorin (1911). The results of the writer from 
numerous crosses, among which was one, the F 2 seed of which was kindly 
sent me by Prof. Bateson, completely confirm the previous studies. 
Group 27 is based entirely on the writer’s own data, but they are too 
few as yet to determine the ratio of non-crossover to crossover gametes. 
Groups 25, 26, and 27 are inherited independently of each other, but, 
as shown in Table III, they belong to three of the seven independently 
inherited groups already demonstrated. The relation of group 24 to 
these, so far as the writer is aware, is undetermined. 
Table IV .—Linked groups of Pisum a 
No. 
Factors. 
Linkage. 
24 
(Bl), S. 
Total 340. 
2 5 
A (Lf). 
Total 2,636... . 
2 5 
A, C, E (Gc), 
and 
26 
R (Tl). 
Total 2,065.... 
MMi 
27 
G, O. 
Total 196. 
265 GIFs : 6 GlAs : 12 EFs : 57 EAs. 
226 GIFs : 17 GlAs : 17 EFs : 64 EAs (8:1). 
189.9 GIFs : 63.3 GlAs : 63.3 EFs : 21.1 EAs (no coupling). 
513 WE : 163 WL : 141 RpE : 1813 RpL. 
505 WE : 154 WL : 154 RpE : 1823 RpL (7:1). 
164.3 WE : 492.9 WL : 492.9 RpE : 1478.7 RpL (no coupling). 
Absolutely coupled, so may be regarded as expressions of a 
single factor A. 
1,466 RT : 20 RA : 15 WT : 564 WA. 
1,471 RT : 15 RA : 15 WT : 561 WA (63:1). 
i, 161 RT : 387 RA : 387 WT : 129 WA (no coupling). 
134 GcGf : 6 GcYf (?) : 16 YcGf (?) : 40 YcYf. 
109.7 GcGf : 36.3 GcYf (?) : 36.3 YcGf (?) : 12.2 YcYf (no 
coupling). 
a Actually obtained F? classes and frequencies given first, followed (i) by approximated amount of 
crossing-over and (2) by theoretical expectancy on a non-linked or no-coupling basis. 
Gl =ss glaucous, F = emerald or non-glaucous Fs — free seeds. As -* adhering or “chenille’' seeds. 
