Table Of ContentA STUDY OF WINTER WHEAT {TRITICUM VULGARE)
AND CHEAT (BROMUS SECALINUS) WHEN GROWN
ALONE AND WHEN GROWN IN COMBINATION
AT DIFFERENT POPULATIONS
BY
HAZO WILLIAM CARTER
B.S., Tennessee Agricultural and Industrial State College, 1943
M.S., Tennessee Agricultural and Industrial State College, 1047
THESIS
SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS
FOR THE DEGREE OF DOCTOR OF PHILOSOPHY IN AGRONOMY
IN THE GRADUATE COLLEGE OF THE
UNIVERSITY OF ILLINOIS, 1962
URBANA, ILLINOIS
UNIVERSITY OF ILLINOIS
THE GRADUATE COLLEGE
September 19. 1952
I HEREBY RECOMMEND THAT THE THESIS PREPARED UNDER MY
SUPERVISION BY HAZOJWILLIAM_CARTER„
ENTITLED A STUDY OF WINTER WHEAT (TRITICUM VULGARE) AND CHEAT (BROMUS
SECALINUS) WHEN GROWN ALONE AND WHEN GROWN IN COMBINATION AT DIFFERENT
POPULATIONS _
BE ACCEPTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR
THE DEGREE OF DOCTOR OF PHILOSOPHY IN AGRONOMY
M440
TABLE OF CONTENTS
PAGE
ACKNOWLEDGMENT
I. INTRODUCTION 1
II. REVIEW OF LITERATURE 6
III. METHODS 11
IV. RESULTS 20
V. DISCUSSION 13
VI. SUMMARY IS
VII. LITERATURE CITED 50
VIII. APPENDIX 52
VITA
ACKNOWLEDGMENT
The author wishes to express his sincere appreciation to Dr. George H.
Dungan for his untiring efforts and effective advisement during the course of
this research, and for his constructive criticism of this manuscript. He also
gratefully acknowledges his indebtedness to Dr. Horace W. Norton for his in
valuable assistance with the statistical phase of the research. In addition,
he expresses sincere thanks to Dr. William Spencer for aid in connection with
radio-active phosphorus experimentj to Dr. James C. Neill for his assistance;
to Dr. W. S. Davis, President, Tennessee Agricultural and Industrial State
University, Nashville, Tennessee for the inspiration given through the years;
to the General Education Board of New York City for fellowships received which
made possible this investigation.
The writer is also ever grateful to his wife, Mary Forbes Carter, for
her inspiration and cooperation, without which this effort would have been
extremely difficult.
A STUDY OF WINTER WHEAT (TRITICUM VULGARE) AND CHEAT (BROMUS SECALINUS)
WHEN GROWN ALONE AND WHEN GROWN IN COMBINATION AT DIFFERENT POPULATIONS
I. INTRODUCTION
Cheat (Bromus secalinus) is often found in wheat (Triticum vulgare) fields
and in threshed wheat grain. It is also considered one of the most common weeds
in fall sown oat fields. Cheat is one of the worst weeds in the California rice
fields. It has caused a great deal of trouble in the production of meadow fescue
seed on account of the very close resemblance of its seeds to those of the fescue.
It is a weedy grass in its habits for it tends to grow in many sorts of waste
places.
Cheat when grown in association with small grain, increases the cost of
production due to extra labor required in handling the crop and cleaning the seed.
It also reduces wheat yields and unless it is completely removed from the wheat
it lowers the market price of the crop. The reduced price is due to the fact that
cheat lowers the quality of wheat for milling purposes.
Cheat is usually removed as dockage from wheat in the markets of the
United States. According to Combs (7) the average dockage in soft red winter
wheat found by supervisors ranged between 1.3 and 1.8 per cent, with an average
of about 1.5 per cent. For a period of thirteen years (1937-194-9) analysis of
samples of soft red winter wheat showed that the percentage of samples carrying
dockage ranged from a low of 6.6 in 19-41 to a high of 17.8 per cent in 1937.
Loss estimates due to cheat dockage have been calculated by the formula—
Pd (bu) x DS (%) x AD$ x Pc (@ bu.) - monetary loss due to dockage. In this
formula "Pd" is production in bushels; "DS" is per cent of dockage carried in the
samples analyzed; "AD" is the average per cent of the wheat that contained
dockage; and "Pc" is the average price per bushel. The results of these calcu
lations are presented in Table 1.
2
Table 1. Losses in the United States due to cheat dockage in soft red winter
wheat, 1937-1949.
Year Production Samples Amount of Amount Price Loss
Carrying wheat carrying of Per because
Dockage Dockage wheat Bushel of
lost as Dockage
Dockage
1000 bu. Perct. 1000 bu. bu. cents dollars
1937 249,769 17.8 44,459 666,885 103 686,891
1938 226,053 13.4 30,291 454,365 63 286,249
1939 194,910 9.4 18,322 274,830 70 192,381
1940 207,405 13.1 27,170 407,550 71 289,360
1941 204,031 6.6 13.466 201,990 101 204,009
1942 148,723 9.8 14,575 218,625 118 257,977
1943 125,216 11.7 14,650 219,750 148 324,330
1944- 203,635 9.6 19,549 293,235 148 433,987
1945 213,350 8.4 17,921 268,815 156 419,351
1946 195,711 12.7 24,855 372,825 198 738,193
1947 236,544 13.8 32,643 489,675 229 1,121,355
1948 257,037 10.7 27,503 412,545 209 862,219
1949 259,709 15.0 38,956 584,340 182 1,063,498
Average 529,215
The losses resulting from cheat dockage ranged from a low of $192,381 in
1939 to a high of $1,121,355 in 1947. The average annual loss for the 13 year
period was $529,215.
Wheat and cheat are winter annuals. They start their growth at approxi
mately the same time in the fall and ripen their seed within a few days of each
other the next summer. When they occupy the same area of land, they enter into
direct competition with each other for nutrients, light, moisture, and space.
In a year of normal rainfall, competition between wheat and cheat is principally
for nitrogen and light. In many cases competition is solely for nitrogen,
especially during the early stages of spring growth. Cheat depresses the crop
yield to a great extent during this period because it is capable of making rapid
growth at the same time the wheat is making heavy demands on the soil for
nitrates.
In some localities cheat is grown as an annual forage crop and produces
3
hay of good quality. In some sections of the country it is a valuable pasture
crop. It also furnishes a good soil cover.
Since this study deals specifically with wheat and cheat a brief de
scription of these two plants is presented.
Wheat (Triticum vulgare) is a member of the grass family and belongs to the
tribe Hordeae. It is an annual or winter annual, grass which grows from 2 to 5
feet tall. It has a spike type of inflorescence which consists of a number of
sessile spikelets each placed at a separate notch or node of the rachis. Flowers
per spikelet range from 2 to 4. The flowering stems are erect, unbranched except
for tiller branches at their base, hollow between the nodes, and approximately
l/8 of an inch in diameter. The blades of wheat leaves are approximately 15
inches long, -^ inch wide, pointed with loose sheaths that are finely hairy or
smooth. Wheat has short hairy auricles and rather prominent serrated ligules.
The roots are fibrous and are usually located near the surface, but in
friable soil they may penetrate to a depth of 7 feet. The plants normally pro
duce two or three tillers under field conditions but individual plants on fertile
soil with ample space may produce as many as 30 to 100 tillers.
Cheat (Bromus secalinus) is a tufted pale green winter annual that grows
from 1 to 3 feet high. It is erect, moderately stout and quite leafy. The stems
are upright, circular, smooth and striated, carrying four or five flat, soft,
pointed leaves with deeply striated sheaths. The lower part of the sheath is
soft and the upper part has an obtuse, ragged, membranous ligule at its apex.
Most cheat plants have five nodes. Its inflorescence is racemed or simple
panicled. The panicles are upright at first, but sometimes the heavy ones bend
over just before maturity. The spikelets are ovate, yellowish green usually
carrying 7 florets with awns about 2 mm. long.
Tillering of cheat plants is influenced greatly by competition. When
grown on productive soil with ample space as many as 12 tillers may be produced
by one plant. Under crowded conditions plants may not tiller at all. Roots of
cheat plants are fibrous and generally shallow.
A plant so similar to cheat that it is sometimes mistaken for it is downy
bromegrass (Bromus tectorum). It, too, is a winter annual which, like cheat,
grows spontaneously as a grass weed.
Most downy brome plants are single stemmed if grown in dense stands.
However, much stooling takes place in thinner stands and several seed stalks
grow from the same root system. The most distinguishing character of downy
brome is the awns which are much longer than those of cheat.
Cheat seed shatters easily when mature. When land covered with cheat
seed is poorly prepared for wheat as simply by discing, the cheat seed germi
nates at the same time as the wheat seed and the plants of the two species
compete directly with each other from the beginning.
Land that is turned in the fall will possibly cover the cheat seeds that
were shattered on the ground the previous summer too deeply for them to germi
nate and emerge at the time the wheat does. The cheat seeds that are turned
under in the fall will not germinate before the following fall when the ground
is turned again. There is some evidence (10) however, that cheat seeds will
not remain viable when buried in the soil for a year.
Cheat can get started in another way. Some cheat seed is often
harvested along with the wheat, and it is very difficult to separate all the
cheat seed from the wheat. As a consequence cheat is frequently sowed with
the wheat seed. This makes man an agent in the perpetuation of this pest in
wheat fields.
Cheat and wheat behave much alike. Formerly it was believed that wheat
degenerated into cheat and since it cheated the farmer out of wheat it was
given the name—cheat. It is still a popular belief among a few farmers that
i wheat turns to cheat. This erroneous idea is due to the rapid, vigorous
growth of cheat and the manner in which it occupies the ground where wheat
has winterkilled. Occasional plants of cheat, which would hardly be noticed
in a vigorous stand of wheat, grow so vigorously and stool so abundantly when
given plenty of space by the winterkilling of the wheat as to give the
impression that the entire crop has turned to cheat.
This experiment was undertaken to get information on the effect of
cheat when grown in association with wheat on the grain and straw yield of
wheat and the effect of wheat on the grain and straw yield of cheat. This
experiment was also designed to get information on how the presence of each of
these plants affects the tillering of the other one when the two species are
grown in close association. Comparative height and diameter measurements of
stems of wheat and cheat when grown alone and in association at different popu
lations were also taken.
The experiment also included a study of the capacity of wheat and cheat
plants to survive the winters in Central Illinois and Middle Tennessee.
6
II. REVIEW OF LITERATURE
No experimental work has been done on the competition between cheat
(Bromus secalinus) and wheat (Triticum vulgare) or between cheat and other
members of the grass family. However, some work has been done on the compe
tition between downy brome (B, tectorum) and some other members of the grass
family.
Although this experiment is chiefly concerned with competition, the
writer feels that the important literature pertaining to other aspects of
Bromus secalinus and Bromus tectorum should be cited. Very little research
of any kind has been conducted on either of these species, however, more has
been done with Bromus tectorum than with B. secalinus.
Vinall (33) says that cheat (Bromus secalinus) has always caused
trouble in the production of meadow fescue on account of the very close re
semblance of its seeds to those of the fescue. They not only look alike, but
they are about the same weight and difficult to separate. He pointed out that
a number of farmers who purchased and planted what they thought was pure meadow
fescue seed found their fields to be largely cheat the following year. The
large increase in the proportion of cheat to fescue was attributed partly to
the greater ability of the cheat seed to germinate under adverse conditions.
Piper (23) refers to the fact that cheat often occurs in wheat fields, as the
two plants have life histories that are quite similar.
In Hoosier Horticulture (2) the statement is made that cheat is a slow
grower in the fall, but it is an extremely rapid grower in the spring. For a
ground cover, cheat may be sown in February or March in unbroken ground where
there is a thin sod of grass or weeds and it will take hold and grox*.
Sampson (28) observed that downy bromegrass was an aggressive invader in the
Wallowa Mountains of Oregon. In an area that had been artifically denuded of
