10 
BULLETIN 137, U. S. DEPARTMENT OF AGRICULTURE. 
and yet it is among the very latest in maturity. Indeed, there is 
some peculiarity about each one of the fourteen when all stages are 
considered. 
VARIATIONS IN THE CULM. 
The culm varies in length, diameter, thickness of walls, exsertion 
of spike, number of nodes, and number of culms per plant. 
LENGTH OF THE CULMS. 
The height of the plant is a note universally taken on all experi- 
mental farms. At any chosen station, some varieties are always tall 
and others always short. This 
distinction is sufficient to prove 
a difference between such va- 
rieties, and as such it is a use- 
ful observation in breeding. 
It is, however, merely a proof 
that a difference exists and is 
not necessarily a difference in 
itself. There is a physiologi- 
cal adaptation of varieties to 
certain places and it may ex- 
press itself in height. 
In 1911 thirteen pedigreed 
selections, representing nine 
minor groups of barley, were 
chosen from the nursery stock 
and planted at four widely 
separated points. At maturity 
the length of culm was care- 
fully noted. The influence of 
climate and soil was surpris- 
ingly great. As will be seen in 
Table I. there is a marked re- 
gional response. The selection 
of Odessa is a Hordeum sati- 
vum hexastichum form occur- 
ring in the commercial Odessa 
variety. In Minnesota it is 
short and unpromising. In 
California it is little better, 
while in the north Kocky 
Mountain and Plains areas it displays an unexpected vigor and is 
very tall. The Abyssinian varieties grow well in California, but are 
short elsewhere. 
Fig. 7. — Curves showing the date of the 
production of the second, third, and 
fourth leaves and the first tiller, the 
emergence of the awns, and the day 
of ripening in 14 selections of barley 
grown at St. Paul, Minn., in 1913. Each 
determination was based on one centgener 
of approximately 100 plants. 
