June 9, 1923 
Rogue Types in Garden Peas 
817 
In 1919, 2,932 F2 plants of the crosses Gradus rogue with Gradus 
(Table II) were grown. Of the 2,932 plants, 65, or 2.3 per cent, were 
volunteer crosses made by insects in 1918. The out-crosses were de¬ 
tected by the appearance of such dominant Mendelian characters as 
smooth seed, blunt pods, and colored flowers in Fj cultures that should 
have contained only recessives for the three characters mentioned. Any 
crosses inter se, or out-crosses with recessive strains, could not be detected, 
but, ap^t from a few plants of Early Giant and of Peter Pan, no varie¬ 
ties which did not exhibit one of the three dominant characters were 
planted in the experimental garden in 1918. In 1920, 3,475 Fj and F3 
plants of the cross rogue with type (Tables II, III and IV) were raised. 
Among them were 42 plants of obviously foreign origin, or about 1.2 per 
cent, showing that the amount of volunteer crossing was considerably 
less in 1919 than in 1918. 
Occasional volunteer crosses have been found among the rogues 
and intermediate rogues, but no count has been kept. However, only 
one case of cross-pollination by insects has been noted among the thou¬ 
sands of typical Gradus plants grown. 
Plants used in crosses have been previously inbred for at least one 
generation. The rogues used were either picked from commercial 
plantings of Gradus or arose de novo in pure cultures of Gradus plants. 
In either case the rogue strains were identical and gave the same results 
in crosses. 
Uncontrolled cross-pollination in Pisum on the scale reported here 
was unlooked for at the beginning of these experiments and no steps 
were taken to insure self-pollination. By the time it was realized that 
rogues were an exception to the general rule that self-pollination is 
invariable in Pisum it was too late to protect the hybrid rogue plants 
in 1919. Aside from the writer's own experience with self-pollinating 
varieties of peas, his garden technic was of course influenced by the 
general conclusion of geneticists and practical horticulturists that peas 
are normally self-pollinated. White (75) found no cross with peas 
having yellow cotyledons among 10,000 seeds with green cotyledons 
grown at the Brooklyn botanic garden. 
BEHAVIOR OF GRADUS ROGUES WHEN CROSSED WITHIN THE GRADUS 
STRAIN 
Fj GENERATION OF CROSSES BETWEEN GRADUS AND GRADUS ROGUE 
In a former publication (4) the results in the Fj generation of crossing 
typical Gradus with Gradus rogue ^ are reported. 
The Fi seedlings were variable in regard to stipule shape, showing 
gradations from typelike to roguelike plants. At maturity with one 
exception the F^ plants were all rogues. 
In addition to the hybrids between rogue and type previously listed 
by the author (4), 134 F^ plants from 37 other crosses were grown, mak¬ 
ing a total from all sources of 282 F^ plants of the cross Gradus X Gradus 
rogue, and reciprocal. Of the 282 plants all but three were classified as 
rogues at maturity. 
3 The name “ Gradus rogue” or '* Rogue” as used throughout this paper refers to the same type of muta - 
tion as that previously referred to U) as a "Rabbit-ear” Rogue. 
