58 Nebraska Agricultural Exp. Station, Research Bui. 7. 
bean parent race, and, likewise while the bush segregates were all 
determinate in habit of growth, some of them were much taller 
than the bush -bean parent race. We need not conclude from this, 
however, that the single factor for habit of growth by which the 
parent races differed was modified in some way by the cross, so 
that, while only determinate and indeterminate habits were to be 
seen in Fo, they were in part of the individuals modified determin- 
ate and modified indeterminate habits. It seems more likely 
that there existed other factors for the difference in height of 
the parent plants besides the factor for habit of growth and that 
segregation of these other factors was responsible for the different 
heights of bush beans and the different heights of pole beans noted 
in the Fo generation. 
From one of the very tall F9 bush plants of this cross there 
has been established a race of very tall bush beans, known here 
as Tallbush, (Figs. 9 and 15) and this has been crossed with a 
race of very short pole beans, Snowflake (Fig. 9). Tall pole 
beans resulted in Fi and there was a wide range of variation in 
height of both the pole and bush segregates in Fo. Apparently 
the factors for number of internodes and for internode length, 
which this very tall race of bush beans received from the tall 
pole-bean parent of the original cross, are able to reproduce the 
tallness of that parent when associated with the factor for in- 
determinate growth secured from a very short pole bean. And, 
moreover, these factors have apparently segregated to produce 
diverse heights in both the pole and bush plants of this later F2 
generation from the cross between the tall bush bean and the 
short pole bean just as they did to produce the diverse types of 
the earlier Fo generation from the cross between the tall pole 
bean and the short bush bean. 
If we were to account for these results by assuming a modifica- 
tion of the factor for determinate growth thru the influence of 
the tall pole bean employed as one parent of the original cross, 
we should have also to make the following additional assumptions: 
(1) That the modification affected the bush habit in different 
degrees in the case of the several ¥2 bush plants, (2) that the modifi- 
cation is constant in the new tall bush race, (3) that the modified 
determinate habit was remodified in the cross between the tall 
bush race and the very short pole race, the modification again 
affecting only a part of the Fo bush plants, (4) that this remodified 
determinate habit was able to modify the indeterminate habit 
in a very definite way in the cross with the short pole bean, so 
that the Fi plants were all very tall pole beans, and finally (5) 
that this new modification of the indeterminate habit was able to 
appear in only a part of the pole-bean segregates of F2. 
