6 Nebraska Agricultural Exp. Station, Research Bui. 7. 
that potential internode length can be determined roughly from 
actual internode length of the first five internodes of bush beans. 
It is also found possible to determine with fair accuracy the inter- 
node length of pole beans by measuring the first 15 internodes, 
which usually include the greater part of those formed during 
the period of growth-rate acceleration. 
It is shown that indeterminate habit of growth in beans is 
fully dominant to determinate habit, that sharp segregation 
occurs in Fo resulting in a ratio of three plants of indeterminate 
habit to one of determinate habit, and that determinate habit 
is constant in Fg while some indeterminate Fs plants breed true 
in F3 and others segregate again into pole and bush plants. 
The difference between indeterminate and determinate habits of 
growth is, therefore, due to a single genetic factor. 
While number of internodes is directly, and internode length 
indirectly, related to habit of growth, these characters are in a 
way distinct from it. There exist distinct types of bush beans 
with respect to both number of internodes and internode length. 
The same is true of pole beans. 
Crossing bush beans of different internode lengths is shown 
to result in an intermediate condition in Fi and a wider range of 
variation in Fo with respect to internode length. The same re- 
sults are secured from crosses between pole beans of different 
internode lengths. 
A cross between a short pole bean and a tall bush bean is 
shown to produce tall pole beans in Fi. F2 consists, on the average, 
of three pole beans to one bush bean, but some of the pole-bean 
segregates have fewer and shorter internodes than the pole- 
bean parent and some of the bush-bean segregates have more 
and longer internodes than the bush-bean parent. 
The same results are shown to follow when a tall pole bean 
is crossed with a short bush bean. From the Fo bush segregates 
of such a cross there has been established a bush-bean race that 
has more and much longer internodes than the bush-bean parent 
race. 
The dominance of indeterminate over determinate habit 
of growth in a cross between pole and bush beans and the simple 
3-1 segregation in F2 are interpreted just as other simple Men- 
delian results are, namely, on the basis of a single dominant, 
genetic factor for the difference between the parents in habit of 
growth. The intermediate height in Fi and the wide range of 
variation in F2, from a cross between two bush beans or between 
two pole beans of different heights, are interpreted in accordance 
with the multiple-factor hypothesis, which postulates that heredi- 
tary, quantitative differences are due to two or more non- 
