42 
Journal o f Agricultural Research 
Voi. XXIX, No. I 
Table XXXV.— Correlation between yield of plant and date of heading of 
material of crosses of Kota and Hard Federation wheats grown at Mandan , N. Dak. r 
in 1923 
r=-0.193± 0.024 
Table XXXVI.— Correlation between date of heading in F 2 and F$ of crosses of 
Kota and Hard Federation wheats grown at Mandan, N. Dak., in 1922 and 1923 
YIELD AND HEIGHT OF PLANT 
From a breeding standpoint it is 
important to determine whether short 
or tall plants are more productive. 
Height also is an important economic 
factor in wheat production. The aim 
of the breeder is to produce a variety 
tall enough to be conveniently harvested 
with a self-binding harvester and still 
produce maximum yield. Taller vari¬ 
eties have no particular advantage. 
They are subject to greater injury from 
storms and use more soil fertility and 
moisture. Hard Federation often is too 
short to be conveniently harvested. 
Kota, on the other hand, is slightly taller 
than necessary. Height, therefore, 
should be given careful consideration 
while making selections of the progeny. 
But it is first necessary to know the effect 
of height on yield. Data on correlations 
between these factors were obtained in 
F 2 material at St. Paul, Minn., and 
Mandan, N. Dak., and F 3 material at 
Mandan. The Mandan F> data are 
presented in Table XXXVII. 
Table XXXVII.— Correlation between yield of plant and height of plant in F 2 
material of crosses of Kota and Hard Federation wheats grown at Mandan, 
Dak., in 1922 
r = 0.405±0.017 
