June 21, 1924 
Gamete Production 
1251 
It is hoped to have data soon on the genetic behavior of comparable material 
from similar back-crosses made during the past summer. 
The classification of the F 2 segregates according to their nodal origin from the 
F x hybrid is shown in Table II. There is a slight tendency for the proportion of 
rogues to nonrogues (broads) to increase toward the upper nodes, but as the total 
number is small, emphasis in the interpretation can not be put on this feature of 
the data. There may be an excess of nonrogue gametes produced by the ovules 
and an excess of rogue gametes produced by the pollen grains. However, the 
numerical differences between the two classes are slight enough to be well within 
the experimental error for so few plants if the real gametic ratio between the 
rogues and nonrogues was 1:1, irrespective of which way the cross was made. 
The ratio of rogues to nonrogues for both crosses combined actually is 77: 78, or 
practically 1:1. 
On the other hand, the occurrence of a large number of rogues in the F 2 genera¬ 
tion above the proportion theoretically expected for a monohybrid ratio can be 
explained by assuming the probable excess production of rogue-bearing male 
gametes indicated by the F x back-crosses actually occurred, especially at the 
upper nodes. The five F x plants used were exceptionally tall and flowered over 
a much longer period than the Gradus types. Consequently the back-crosses 
were made with flowers largely from the eighth to the fourteenth nodes of the 
hybrids. The self-fertilized plants came for the most part from the fourteenth 
to the twentieth nodes on the main stem, or from branches of the main stem pro¬ 
duced late in the season. 
From the foregoing it appears that the zygote heterozygous for the rogue 
factor is unstable. Apparently the presence of the rogue factor causes a change 
or mutation of the allelomorphic factor which entered the hybrid from Rice’s 
330. This genetic change during the development of the plant is most often due 
to the rogue factor itself, but occasionally it may take some other form, or the 
rogue factor itself may change. In either event a roguelike plant, possibly the 
F 2 intermediates or the chimeras here described, is the outward expression of 
the change. 
A comparable case has been reported by Blaringhem 6 , who studied the 
behavior of a mutation in Pisum with green cotyledons from a variety with 
yellow cotyledons. On self-fertilization the green-seeded peas gave varying pro¬ 
portions of plants with green, yellow, and variegated green and yellow seeds. 
The yellow seeds breed true, while the variegated and green seeds repeat the 
splitting. Seven self-fertilized green-seeded plants gave only green-seeded plants 
from the upper and lower nodes, while the middle nodes gave all three types. 
The totals for all seven plants were 118 green, 26 variegated, and 17 yellow. 
This author describes the phenomenon as one of hereditary mosaic, evidently 
believing that the green plants are a genetic mosaic of green and yellow and 
that “ disjunction” of the two characters takes place under certain environmental 
conditions. He suggests that the manifestation of the true nature of the green- 
seeded plant or mosaic is dependent upon the age of the plant and the en¬ 
vironment, especially temperature and humidity. 
As Bateson and Pellew point out in discussing the genetic behavior of 
the intermediates they have described, where the gametic output is so fluctu¬ 
ating it is perhaps unwise to hypothecate a factorial system to interpret the 
results. Nevertheless, it is believed that here the presence of rogue and non- 
rogue gametes in the ratio of approximately 1:1, at the lower nodes at least of 
the F x hybrid between Rice’s 330 and rogue, indicates a single-factor difference 
• BLARINGHEM, L.—HfiRtDITfc ANORMALE DE LA COULEUR DES EMBRYONS D’UNE VARlfiTfi DE POIS 
(pisum sativum l.). Compt. Rend. Acad. Sci. [Paris] 174:877-879. 1922. 
