June 9, 1923 
Rogue Types in Garden Peas 
851 
The discrepancy between observation and theory is great in respect 
to the ratio of rogues to nonrogues in the segregating Fg families. How¬ 
ever, the fact of segregation is considered more important than the 
ratios obtained. The instability of the heterozygous Xx' combination, 
though not leading to a complete elimination of the x' gametes, by 
mutation of x' to X, is such as to produce an excess of X gametes over 
the number that would normally be formed if somatic mutation did not 
take place. 
SUMMARY 
(1) The Gradus variety of Pisum sativum, characterized by broad, 
wavy, emarginate stipules with a mean ratio of 
occasionally produces rogue mutations, characterized by narrow, fiat, 
pointed stipules with a mean ratio of 2.35. 
(2) Primary rogues are produced from Gradus types by a mutation 
of a single factor x to X. They are therefore heterozygous, of the 
formula xX. They give an Fg of homozygous secondary rogues, XX, 
through recurrent (mass) somatic mutation of the x factor to X. Such 
recurrent mutation is believed to occur because of the instability of the 
combination of xX. 
(3) The crosses Gradus X Gradus rogue, and reciprocal, likewise pro¬ 
duce an unstable F^ germ plasm in which mass, somatic mutation of x to 
X occurs. 
(4) The effect of mass somatic mutation in the F^ hybrid is to produce 
a germ plasm homozygous for the X factor in by far the greater number 
of the somatic cells. At gametogenesis only an occasional x gamete is 
produced. The Fg generation consists almost entirely of rogues (XX), 
the Gradus type (xx) very rarely appearing. 
(5) In addition to the x factor a second factor y for stipule shape is 
present in both Gradus and Gradus rogue. The factor y is linked with 
the a factor for white flowers. 
(6) The English Mummy pea, a nonrogue producing variety, has a 
stipule ratio of 2.05 determined by a factor Y, allelomorphic to y of 
Gradus, and linked with the A factor for colored flowers. 
(7) In crosses between Gradus and Mummy the number of cross-overs 
between AY and ay is approximately 20 per cent. 
(8) Mummy, in addition to the Y factor, has a factor x' which is allelo¬ 
morphic to the X factor in Gradus type, therefore to the X factor of 
Gradus rogue. The x' factor is practically identical with the x factor in 
its expression but differs in that it only rarely mutates to X, even in the 
combination x'X. 
(9) The germ plasm of the F' cross, Gradus rogue (yyXX) X Mummy 
(YYX'x') is fairly stable. In the F' hybrids, YyXx', the factor x' 
mutates to X but not to such an extent as to prevent at gametogenesis 
the formation of the usual gametes, XY, Xy, x'X, and x'y, as indicated 
by the appearance in the Fg generation of rogues (having the X factor), 
Graduslike plants (having the x' and y factors), and Mummylike 
segregates (having the x' and Y factors). 
(10) The expected 3 : i ratio of rogues to nonrogues in the Fgand succeed¬ 
ing generations obtained from the heterozygous Xx' plants, is disturbed 
by an excess of X gametes and consequently of XX and Xx' zygotes. 
(11) Inheritance of the factors for stipule shape X and y in Gradus 
rogue is Mendelian. Normal inheritance is obscured by somatic muta¬ 
tion of the factors x and x' when in the Xx or Xz' combination. 
