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UMI

MORPHOLOGY, TEMPERATURE TOLERANCE, AND CONTROL
OF TWO WEEDY SORGHUM SELECTIONS IN MICHIGAN

By

Dennis R. Cosgrove

A DISSERTATION

Submitted to
Michigan State University
in partial fulfillment of the requirements
for the degree of

DOCTOR OF PHILOSOPHY

Department of Crop and Soil Sciences

1987

ABSTRACT

MORPHOLOGY, TEMPERATURE TOLERANCE, AND CONTROL
OF TWO WEEDY SORGHUM SELECTIONS IN MICHIGAN

By

Dennis R. Cosgrove

In order

to characterize weedy

sorghum populations

in

Michigan, an overwintering and a non-overwintering selection
were

compared

New

York,

with

Ohio,

overwintering
selection

seed

Tennessee,

selections

of

Sorghum

Characteristics
production

overwintering

and

and

from
almum

allocation,

the

rhizome

from

morphology,
effects

sprouting,

Ontario,
and

Illinois,

(Parodi)

were

from

Mississippi

Ontario,

compared

germination,

selections

of
and

non­
and

a

Minnesota.
dry

weight

temperature
survival.

on
The

effect of cold temperatures on the degree of saturation of
fatty

acids

selections,
investigated
differential

in rhizome

cell membranes

of the

the

Tennessee

selection,

to

determine

if

cold

tolerance.

this
Control

and

may
of

play
the

two Michigan
almum
a
two

part

was
in

Michigan

Dennis R. Cosgrove
selections

was also

evaluated

non-selective herbicides.
larger

seeds,

flowered

earlier,

dry weights
seeds
was

of

taller,

non-overwintering
that

sprouting

selections

thicker
and

overwintering

than

of

was

selective

Non-overwintering

leaves,

were

than

greater

rhizome

wider

using

at

Rhizomes

fewer

leaves,

lower

rhizome

Germination
low

overwintering

lower.

tolerated

produced

selections
the

selections had

culms,

selections.

and

temperatures

selections

of

of

but

overwintering

lower temperatures

than

non­

overwintering ones but there were no consistent differences
in

the

degree

Control

of

greater

with

the

quizalofop
pionic

of

saturation

of

the

non-overwintering

single

early

membrane

Michigan

postemergence

fatty

acids.

selection
applications

was
of

(2-[4-(6-chloro-2-quinoxalinyl)oxy]phenoxyl]pro­

acid),

fluazifop

{(+)-2-[4-[(5-(trifluoromethyl)-2-

pyridinyl)oxy]phenoxy]propanoic

acid},

haloxyfop

(2— [4— [[3—

chloro-5-(triflouromethyl)-2-pyridinyl]oxy]phenoxy]propanoic
acid),

and

sethoxydim

{2- [1-(ethoxyimino)butyl]-5-[2-

(ethylthio)propyl]-3-hydroxy-2-cyclohexen-l-one} in soybeans
[Glycine

max

provided

by

(L.) Merr.]

while

the non-selective

few differences
herbicides

(phosphonomethyl)glycine),

sulphosate

carboxymethylaminomethyl

phosphonate),

in

control

glyphosate

(N-

(trimethylsulphonium
and

HOE-661

(ammonium-(3-amino-3-carboxypropyl)-methyl phosphinate) were
observed.

The

results

of

this

study

suggest

that

two

distinct sorghum species exist as weed problems in Michigan,

Dennis R. Cosgrove
overwintering ecotype of Sorghum halepense
non-overwintering ecotype of £3. a l m u m .

(L.) Pers. and

ACKNOWLEDGEMENT

I

would

members

of

like
my

to

thank

guidance

Dr.

William

committee,

Meggitt

Drs.

Kells,

and

the

Putnam,

Penner, and Stephenson, for their suggestions and assistance
during

the

course

of

this

study.

I

would

also

like

to

recognize the technical assistance of Mark Benjamin and Mike
Leen.
the

Finally,
students

Springs,

MI,

I would like to thank Bernard Anderson and

and

staff

Larry

at

Andrews

Brodbeck

of

University
Sunfield,

in

MI,

Berrien
and

Ray

Christenson of Greenville, MI for the use of their cropland
for the field experiments included here.

TABLE OF CONTENTS
Page
LIST OF TABLES ..............................................

v

LIST OF F I GURES ............................................. viii
INTRODUCTION................................................

1

CHAPTER ONE
Literature Review......................................
Literature Cited.......................................

5
31

CHAPTER TWO
CHARACTERIZATION OF MORPHOLOGICAL VARIATION
OF WEEDY JOHNSONGRASS [SORGHUM HALEPENSE
(L.) PERS.] POPULATIONS IN MICHIGAN..................

37

Abstract.............................................
37
Introduction........................................
39
Materials and M e t h o d s ..............................
44
Results and Discussion.............................
47
Seed and Seedling Characteristics..............
47
Morphological Characteristics (Vegetative)
48
Morphological Characteristics (Reproductive)...
49
Dry W e ights .......................................
50
Dry Weight Allocation............................
51
Literature C i t e d ....................................
59
CHAPTER THREE
EFFECTS OF TEMPERATURES ON THE SEED GERMINATION,
VIABILITY, AND SPROUTING OF RHIZOMES AND FATTY
ACID CONTENT OF SEVERAL SORGHUM SELECTIONS..........

61

Abstract.............................................
Introduction........................................

61
63

iii

Page
Materials and M e t h o d s ............................... 68
Rhizome Sprouting vs. Temperature................. 69
Seed Germination vs. Temperature................. 70
Rhizome Burial Study.............................. 70
Rhizome Temperature Tolerance.................... 71
Cell Membrane Lipid Composition vs.
Temperature...................................... 72
Results and Discussion.............................. 77
Effect of Temperature onRhizome Sprouting....... 77
Effect of Temperature on Seed Germination....... 79
Effect of Cold Temperature on Rhizome
Viability........................................ 82
Overwintering Ability of Eight Sorghum
Selections....................................... 83
Effect of Cold Temperature on Fatty Acid
Composition of Cell Membrane Phospholipids.... 86
Literature C i t e d ..................................... 98
CHAPTER FOUR
CONTROL OF TWO WEEDY SORGHUM SELECTIONS IN
MICHIGAN WITH SELECTIVE AND NON-SELECTIVE
HERBICIDES............................................... 100
Abstract.............................................. 100
Introduction.......................................... 103
Materials and M e t h o d s ................................105
Johnsongrass Control in Soybeans................. 105
Johnsongrass Control with Non-Selective
Herbicides....................................... 106
Results and Discussion........ ..................... 108
Johnsongrass Control with Selective
Postemergence Herbicides........................ 108
Johnsongrass Control with Non-Selective
Herbicides........................................Ill
Literature C i t e d ..................................... 125
CHAPTER FIVE
SUMMARY AND CONCLUSIONS................................. 127

iv

LIST OF TABLES
Page
INTRODUCTION
1.

Estimated acreage in Michigan infested with
Johnsongrass by county................................

3

CHAPTER TWO
1.

Growth parameters me a s u r e d ............................. 46

2.

Seed weight and size, days to emergence, and
height 7, 14, and 28 days after emergence for
10 sorghum selections.................................. 54

3.

Leaf width, leaf length, stem circumference,
plant height, number of leaves, branches,
nodes, and tillers of 10 sorghum selections.........

55

4.

Seedhead length, number of whorls per seedhead,
number of branches per whorl, number of seeds
per plant, and number of days to flowering for
10 sorghum selections.................................. 56

5.

Rhizome, seed, root, crown, shoot, reproductive,
vegetative, above ground, below ground, and
total dry weights of 10 sorghum selections..........

57

Dry weight allocation to rhizomes, seeds, roots,
crowns, reproductive, vegetative, above ground,
and below ground tissue of 10 sorghum selections....

58

6.

CHAPTER THREE
1.
2.

Effect of temperature on rhizome sprouting of
10 sorghum selections..................................

90

Effect of temperature of seed germination of
10 sorghum selections..................................

91

v

Page
3.
4.
5.

Effect of cold temperature on rhizome survival
of 4 sorghum selections...............................

92

Overwintering ability of 8 sorghum selections
at 2 locations in Mi c h i g a n ............................

94

Effect of cold temperature on fatty acid
composition of rhizome phospholipids in 4
sorghum selections.....................................

97

CHAPTER FOUR
1.

Johnsongrass control in soybeans 1984 at 2
locations in Michigan with selective
postemergence herbicides...............................115

2.

Johnsongrass control in soybeans in 1985 at 2
locations in Michigan with selective
postemergence herbicides...............................116

3.

Control of Johnsongrass regrowth in soybeans
at two locations in Michigan one year after
treatment with selective postemergence herbicides...118

4.

Effects
of carrier volume and stage of growth
at time of application on Johnsongrass
control 21 days after treatment with
non-selective herbicides in 1984...................... 119

5.

Effects
of carrier volume and stage of growth
at time of application on Johnsongrass
control 21 days after treatment with
non-selective herbicides in 1985...................... 120

6.

Effects
of carrier volume and stage of growth
at time of application on Johnsongrass
control 42 days after treatment with non-selective
herbicides in 19 8 4.....................................121

7.

Effects
of carrier volume and stage of growth
at time of application on Johnsongrass
control 42 days after treatment with non-selective
herbicides in 19 8 5 .....................................122

vi

Page
8.

Effects of carrier volume and stage of growth
at time of application on control of Johnsongrass
regrowth one year after treatment with
non-selective herbicides in 198 5 ...................... 123

9.

Effects of carrier volume and stage of growth
at time of application on control of Johnsongrass
regrowth one year after treatment with
non-selective herbicides in 1 9 8 6 ...................... 124

vii

LIST OF FIGURES
Page
INTRODUCTION
1.

The distribution of Johnsongrass in
Mic h i g a n .................................................

4

CHAPTER ONE
1.

The distribution of Johnsongrass in the
United States...........................................

30

CHAPTER THREE
1.

Percent rhizome survival following exposure
to 0C for 1, 2, 3, or 4 d a y s ..........................

93

2.

Soil Temperature —

Southern L o c a t i o n................

95

3.

Soil Temperature —

Northern Loca t i o n................

96

viii

INTRODUCTION

Johnsongrass
serious

weed

[Sorghum halepense

problem

introduction

in

in

the

the

early

(L.) Pers.]

United

has been a

States

1800's.

since

Though

its

typically

associated with the warmer climates of the southern U.S., in
recent

years

northern

reports

regions of

of

Johnsongrass

the U.S.

have

infestations

increased.

in

the

Johnsongrass

infestations have been known to exist in Michigan since the
1950's.
extreme

At

that

time

southwestern

relatively

warm

infestations
counties

soil

reports
Michigan
results

of

of

illustrate
increased
reports

Johnsongrass

have

to

survey
what

populations
developed,

in
or

conducted

since

questions
Michigan
was

more

Table

extent

in Michigan
raised

rhizomes
in

increased.

a

where

temperatures

through the winter enabled

were

1
in

and
to

the

was

assumed

the

heavy

snow

survive.

northern
and

1 9 5 0 's.

as

to

Figure

Recently,

1

show

These

These

to

the

have

increasing

Johnsongrass

ecotype

tolerance

in

results

infestations

whether
an

cover

locations

1986.

the

developing,

in

it

Johnsongrass

represented

isolated

which
the

had

cooler

temperatures in this region which would enable infestations

1

2

to increase and become a serious weed problem in the state.
With

this

in

mind,

studies

were

undertaken

with

these

objectives:

—

to characterize Johnsongrass populations in Michigan
in relation to populations

from other parts of the

U.S.

—

to

determine

between
Michigan

if

these

physiological
populations

populations

to

differences

which

would

exist
enable

better

withstand

cold

control

measures

for

temperatures.

—

to

evaluate

Johnsongrass

existing
and

determine

if

these

practices

equally effective on populations in Michigan.

are

3

Table 1.

Estimated
acreage
in
Johnsongrass by county.

County
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.

Allegan
Barry
Bay
Berrien
Branch
Calhoun
Cass
Clinton
Eaton
Emmet
Genesee
Hillsdale
Ingham
Ionia

Michigan

Acreage
Infested
200
300
2-3,000
1,000
2,000
2-5,000
1,000
100
600
?
100
2-5,000
200
50

Total estimated infested acreage:

infested

County
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.

Jackson
Kalamazoo
Kent
Lenawee
Livingston
Mason
Menominee
Monroe
Montcalm
Ottawa
Shiawassee
St. Joseph
VanBuren
Washtenaw

16,000-23,000.

with

Acreage
Infested
200
?

ioo
20
0

?
1,000
?
300
1,000
100
2,000
200
200

....

i| nr"*w

Michigan.

^ L s - k -iL_3V

1©

4 of if To 1 © if

u.5—

i

.- 0

1

)1 r J /
W

-

<

CD

j,

> — -r’i___
j i’_ y
C ,
.8

h

rf

$

/

5

^

The

vf

!

1.

.rj

IvA;r
*
~
r
r
T'iii (
(

Figure

^

n
(<e.

distribution

of

..=J

o

Johnsongrass

in

'

;

CHAPTER ONE

LITERATURE REVIEW

Name

Sorghum halepense

(L.) Pers., Johnsongrass

Description

Johnsongrass is described by Warwick and Black
a perennial grass with

fleshy rhizomes to 1 cm in diameter

and 2 m in length, often rooting from the nodes,
partially

covered

with

brown

scale-like

(flowering stems) erect, usually unbranched,
0.5-2.0
roots,

cm in diameter,
nodes

sometimes

(66) as

internodes

sheaths.

Culms

0.5-2.5 m tall,

often with basal adventitious prop
with

fine

hairs.

Leaves

cauline;

leaf sheaths often with a waxy secretion at the base, veins
prominent,

surface

overlapping;

margins

open,

ligules membranous with a hairy fringe,

2-5 mm

long;

auricles

green

or

hairless

absent;

sometimes

and

blades

with

rolled

purple

5

ribbed,

in bud,

pigments,

flat,

20-60

cm

bright
long,

6

1.0-3.0 cm wide, mid-vein conspicuous,

everywhere hairless,

with scabrous

(small rough) projections on the lower surface

and margins.

Inflorescence a large, erect panicle, at first

compact,
hairy,

later
up

numerous

to

spreading
50

cm

whorls,

usually

without

and

open,

pyrimidal,

long

and

20

slender,

the

lower

up

to

2-5

cm

from

spikelets

for

cm

wide.

purplish,

Branches
15

cm
the

in

long,
base.

Spikelets in pairs or at the end of each branch in threes,
usually disarticulating as a unit.

Spikelet units with one

sessile and either one or two pedicelled spikelets.
spikelet,

4-6

compressed;

mm

long,

perfect,

1.8-2.5

green,

mm

wide,

almost

dorsiventrally

glabrous

to

silky; glumes becoming leather-like at maturity;
flat

across

upper

glume,

slightly
rolled

the

boat

around

back,

7-11

rounded

veins,

shaped,
the

tip

acute

lemma;

on

the

three

lemma

margins

3-11

hyaline,

appressed

lower glume
against

toothed;

entire,

Sessile

upper

veins,

the

glume

margins

ciliate,

3-5

mm

long, one to three veins, usually with a 1.0 to 1.6 cm long
awn

which

deciduous

generally
as

the

develops

seed

ripens;

after

anthesis

palea hyaline,

and

is

early

3-4 mm

long;

two free lodicules about 0.5 mm long;

three anthers 2.2-3.0

mm

free to the base

long;

yellow,

ovary apex glabrous;
pink,

red,

purple,

pedicels densely ciliate,
glumes

green-purplish,

styles

or black.

Pedicelled

and

spikelet,

1.5-4.0 mm long; male or sterile;

lanceolate

4-6

mm

long,

1.5-2.0

mm

7

wide, lemma awnless,

lemma and palea hyaline with 0-2 veins,

shorter than the glumes.
4.0-6.6

mm

long,

Grain remains enclosed by glumes

2.0-2.6

mm

wide,

oblong-ovate,

glumes

reddish brown to shiny black, glossy, marked with fine lines
on the surface.

Distribution

Johnsongrass occurs in all major agricultural areas of
the world from latitude 55N to 45S

(28) .

into the United States in the 1830's
all but

a dozen

Johnsongrass
2).

Most

has

states
been

(see Figure
reported

infestations

in

as

far

north

(9) and now occurs in
1)

27

Michigan

half of the lower peninsula,
reported

in

however,

as

It was introduced

(65) .
counties

occur

in

In Michigan,
(see Figure
the

southern

Johnsongrass has been

Menominee

county

in

the

southwestern upper peninsula.

Cytology and Taxonomy

Sorghum halepense belongs to the sorghum section of the
genus Sorghum.

Several

section have been made.

treatments of the taxonomy of this
Snowden

(60) divided the section in

two subsections, Arundinaceae, consisting of diploid

(2n=20)

species,

(2n=40)

and

Halepensia

consisting

of

tetraploid

8

species.

Snowden

described

DeWet

Huckaby

(20)

and

52

species

divided

species, Sorghum bicolor

the

in

the

section

section.

into

a

single

(L.) Moench, with two subspecies S.

bicolor ssp. bicolor which contains the cultivated sorghums,
companion weeds, and semiwild relatives, and £3. bicolor ssp.
halepense.

This

subspecies

distinct complexes,
The

ecotype consists

narrow leaves and extends
it

is

two

replaced

by

of

small

ecotype

plants

with

from Asia Minor to West Pakistan
a

larger

more

ecotype which extends to southern India.
Mediterranean

morphologically

a Mediterranean and a tropical ecotype.

Mediterranean

where

contains

which

is

robust

tropical

It is the smaller

believed

to

have

been

introduced into the new world and is commonly referred to as
Johnsongrass
more

robust

miliaceum
cultivated

(52).

DeWet and Huckaby

tropical

ecotype,

sometimes

sorghum.

(2n=40)

include diploid
DeWet
two

(19)

referred

to

the

as

S.

Harlan

and

DeWet

taxa,

(2n=20)

and

£3.

taxa.

(25)

divided

the

(L.) Pers. to include

bicolor

(L.)

Moench

to

The most recent treatment by

recognizes three species in the section sorghum;

rhizomatous

(Kunth)

suggested

(59) may have resulted from an introgression with

section into two species, S. halepense
tetraploid

(20)

species,

Hitchcock

£3.

halepense

(2n=20) and

£>.

and

bicolor

S.

prop in gu urn

(2n=20)

includes all annual wild, weedy, and cultivated taxa.

which

9

In Argentina an
unknown

cultivated

(Parodi)

(23).

introgression

sorghum has

S.

almum

of S.

been

halepense with an

described

resembles

S.

S.

almum

halepense in

being

rhizomatous and having 40 somatic chromosomes
it

differs

stems,

from

broader

upwards.

S_.

halepense

leaves,

almum

and

also

in

having

shorter

has

as

(18), however,

taller,

rhizomes

larger

thicker

which

caryopses

and

curve
larger

pedicles with the sessile spikelets attached to the pedicel.
Simon

(58) has prepared a key in which he distinguishes

almum

from

miliaceum

S.

halepense

(Mediterranean

(tropical ecot y p e ) .

ecotype)

and

thicker

culms.

S.

almum

is

greater degree

as well as

distinguished

these two through larger sessile spikelets,
color,

S.

S. halepense is distinguished

from S. miliaceum through its wider leaf blades,
taller

and

S.

from

shiny black seed

of branching in the panicle,

as well

as shorter, thicker rhizome internodes.

Seasonal Growth and Development

Johnsongrass plants arise from both seeds and rhizomes
present in infested areas.
from

each

showed

is

seeds

similar
require

Growth and development of plants

(29, 40, 53),
10C

higher

however,

temperatures

than was required for rhizome sprouting.

Horowitz
to

(29)

germinate

This difference in

temperature requirement results in rhizome germination prior

10

to

seed

germination

in

field

situations.

Plants

arising

from seed exhibit more rapid leaf production in early stages
of growth
from

(29, 40) therefore seedlings emerging after plants

rhizomes

show

equal

aerial

development

soon

after

emergence.
Rhizome
3-7

leaf

January

initiation

stage

(33, 35, 53).

and March

and 3 months,
seedings

seedings

Plants

had varying

the

plants

not produce

of

in

top

related

to

42,

June,

59,

and

growth

at

the

is

slow

flowering.
began

at

but

Oyer
the

et

age

of

the

increases

rapidly

al.

reported

(53)

leaf

stage

and

between the boot and dough stages.
a rapid

increase

blooming.
in

in

Anderson

rhizome

rhizome
et al.

production

from

between

Early in the

life cycle,

for

days

7

after

seeding times

time

of

plant

rhizome

with

(4)
the

flowering

the

rhizome

reached

production

but

after

onset

and

seed
(29)

of

production
its

maximum

(40)

reported

the

start

found the greatest
mature

that

Initial rhizome

McWhorter

onset of winter dormancy while Horowitz
relationship

(29),

suggests rhizome initiation is not

the

seven

the

and September
42

temperature may be the determining factor.
growth

in

rhizomes

from each of the different

amounts

are

In a study by Horowitz

while May,

rhizomes

initiation thus Horowitz
directly

when

did

respectively,

produced

planting.

occurs

stage

of

increase
to

the

found no causal

rhizome

production.

vegetative growth exceeds

rhizome

11

production,

however

predominates.

after

McWhorter

flowering,

(40)

found

that

rhizome
the

rate

growth decreased progressively after blooming.
(53)

found

plants

vegetative

were

in

the

growth

dough

reached

stage

a

then

growth
of

leaf

Oyer et al.

maximum

gradually

when

the

decreased

until the end of the season.
Johnsongrass ecotypes vary in their ability to produce
rhizomes.

Production of rhizome nodes varied from a maximum

of 229 in a study by McWhorter and Jordan
in a study by Anderson et al.

(4) .

(49)

up to 5,200

Keeley and Thullen

(35)

investigating the influence of planting date on Johnsongrass
growth
sown

reported

in May

later

400

with

less

plantings.

production

of

grams

of

rhizomes

rhizome

Lolas

200-600

and

production

Coble

grams

produced

per

from

(38)
plant

on

plants

earlier

reported

rhizome

depending

length of the original rhizome section planted.

or

on

the

Keeley and

Thullen

(35) found that rhizomes accounted for 13%, 25%, and

40%

the

total

for

plants

of

sowing

accounted

for 16%,

of the total

fresh
sown
9%,

in

in

Israel.

6,

April

9,

and

12

to

August

and 6% and shoots 70%,

fresh weight.

production of 40 meters
conducted

weight

Horowitz

(31)

found

the

ratio

after

while

roots

66%,

and 54%

reported rhizome

and 450 grams per plant in a study
In

this

study,

rhizome

equal to 90% of the total subterranean weight.
(53)

weeks

of

top

growth

to

weight

was

Oyer et al.

rhizomes

to

be

12

approximately

1.0

Horowitz

reported

(31)

at

the

end

of

the

growing

this ratio to vary

season

from 0.4

while
to

0.9

but was never greater than 1.0.
McWhorter

(40) reported the emergence of seed stalks at

27 days after emergence with 80-90% of the total seed stalk
growth

occurring

bloom occurred

one

week

preceding

approximately

46 days

early

bloom.

Early

after emergence after

which plants were in continuous bloom throughout the season.
Keeley and Thullen
at

6-7 weeks

(35) also reported the onset of flowering

after emergence with viable

weeks after flowering.
of

varying

on

Johnsongrass

seedhead

obtained

Wedderspoon

at
(11)

10.5

and

studying

three

and Louisiana,

found

in

populations

a

at

study by Keeley and Thullen
of

planting

on

The highest seed yields

Johnsongrass

16

Burt

populations

flowering was
hour

and

inhibited

photoperiod.

In

a

(35) investigating the influence
no

such

dependence on daylength for flowering was established.

Peak

flowering

date

Knight

reduced at

12 hour photoperiods.

from Maryland
three

2

12, 14, and

formation was

photoperiods greater than 12 hours.

all

flowering,

(36) observed flowering at 8, 10.5,

16 hour photoperiods but

were

collected

In a study investigating the effects

photoperiods

and Bennett

seed

for plants

Johnsongrass

development,

sown in May occurred when day lengths

were 14 to 14.5 hours while peak flowering from plants sown
in

August

occurred

when

daylengths

were

11

to

12

hours.

13

Total

seasonal

Thullen
plant

production

of

seed

is

high.

Keeley

and

(35) observed seed yields of up to 20,000 seeds per

while

Horowitz

(31)

found

28,000

seeds

per

plant

produced in a study investigating the spread of Johnsongrass
plants.
Vegetative
and

production

photoperiod.

is

Ingle

effected

and

Rogers

Johnsongrass selection from Indiana,
increased

with

temperature

hour photoperiods,
was

the

optimum

Wedderspoon

(11)

up

to

however under
temperature

found no

by both

temperature

(34),

using

found shoot dry weights

32C

when

grown

under

12 hour photoperiods,

for

a

shoot

growth.

27C

Burt

significant differences

16

and

in shoot

weight for three Johnsongrass selections grown under 8, 12,
and

16

hour

higher
30C.

photoperiods,

however,

total

fresh weight

was

for all selections when grown at 35C than at 25C or
McWhorter

and

Jordan

(50)

studying

the

effects

of

temperature and light intensity on Johnsongrass growth found
maximum dry weight production at 32C and 19 klux,
maximum

production

of

individual

plant

parts

however,

varied

with

temperature and light intensity.

Factors Affecting Rhizome Production and Sprouting

Many factors may effect the production and sprouting of
Johnsongrass rhizomes during the growing season,

among them

14

soil temperature, soil type, soil moisture, depth and length
of

the

primary

Several

rhizome,

studies

have

effect of temperature
reported

13.5%

at 30C.

Horowitz

temperature,

been

conducted

on rhizome bud

sprouting at 15C,

and
to

photoperiod.

investigate

sprouting.

Hull

81.5% at 22.5C,

the
(33)

and 91.5%

(29) investigated bud sprouting at several

temperatures from IOC to 39C and obtained maximum sprouting
at 28C.

Thus, Johnsongrass rhizomes have a relatively high

temperature

requirement

for

sprouting.

Soil

type

has

significant effect on depth of rhizome production.
production has been shown to decrease with depth.
(30)

reported

60%,
in

30%,

and

weight

found

the

0-15

layer,

respectively.

In

10%

of

the

total

cm,

15-30

cm,

and

a

second

study,

a

Rhizome
Horowitz

subterranean

30-45

cm

Horowitz

soil
(31)

reported 80% of the rhizome dry weight in the upper 20 cm of
the soil and that rhizomes did not penetrate deeper than 40
cm.

McWhorter

(45) found 80% of the rhizomes in the top 7.5

cm layer of a clay soil while
in the upper

80% of the rhizomes occurred

cm of a sandy loam soil.
Total rhizome
3
production was 4.94 kg/m
in a clay soil compared to 12.29
kg/m

12.5

in a loam.
Soil

viability
little
rhizomes

temperature
of

cold

also

rhizome
hardiness.

exposed

to

has

buds.
In

a

profound

Johnsongrass
a

temperatures

study
of

by

-3C

or

effect

on

exhibits
McWhorter
lower

the
very
(45),

for more

15

than 4 hours did not survive.
did not
Hull

(33) also found rhizomes

survive exposure to temperatures of -3.5C or less.

states

organs

Hull

that

while

contain

Johnsongrass

perennial

fructosans

as

rhizomes

organs
the

of

major

are

most

starch

storing

temperate

grasses

storage

carbohydrate

and

that this may be the basis for the lack of cold hardiness in
Johnsongrass

rhizomes,

however,

other

studies

have

shown

sucrose to be the major storage carbohydrate in Johnsongrass
rhizomes

(9, 41) .

Stoller

(61)

investigating the differen­

tial cold tolerance of Johnsongrass and quackgrass rhizomes
found quackgrass
-17C

while

Stoller
acids

rhizomes

tolerated temperatures

Johnsongrass

reported

rhizomes

a higher

in quackgrass

were

proportion

rhizomes

and

of

as

killed

low as

below

unsaturated

suggested this

however,

find

a

significant

difference

fatty

difference

may contribute to the cold tolerance of quackgrass.
not,

-9C.

in

He did

the

polar

lipids important in membrane structure.
Higher
may result

temperatures
in decreased

and

desiccation

in

rhizome viability.

dry

soil

also

McWhorter

(45)

reported exposure to temperatures of 50-60C killed rhizomes
within

1 to

3 days.

Drying

for

6 days

weight prevents sprouting of rhizome buds
al.
were

to

22%

(29).

of

initial

Anderson et

(4) also found a reduction in germination when rhizomes
dried

below

40%

germination below 20%.

moisture

and

complete

absence

of

16

Growing temperature and photoperiod also affect rhizome
production.
weight
to

increased

35C

also

Burt and Wedderspoon

for

a

selection

produced

under

a

12

photoperiod.

as growing

(11)

temperature

from

16

hour

McWhorter
light

increased

Mississippi.

a greater dry weight
to

found rhizome

of

This

fresh

from 20C
selection

rhizomes when

photoperiod

than

Jordan

investigating

and

(50)

intensity and temperature

an

grown

8

hour
the

effects

of

on Johnsongrass

growth,

found rhizome development increased with increasing

light intensity from 9 to 19 klux and was maximum at 32C and
minimum at 40C.
Rhizome
sprouting

bud

dormancy

through

apical

could increase the
Johnsongrass
favorable
reserve
due

and

dominance

infestation

conditions

adverse

applications

are

of
both

axillary
means

bud

which

colonizing ability and persistence of a
through

exist.

supply of rhizomes

to

inhibition

These

Hull

sprouting

traits

also

until

ensure

a

in the event some buds are lost

environmental

(52).

delaying

(33)

conditions

detected

or

herbicide

no natural dormancy

in single node rhizome sections harvested at any time of the
year.
study.
stage,

Horowitz
Anderson
however,

temperature
demonstrated

(30) reported similar results in a separate
et

al.

Monaghan

suppression
apical

(4)

refer

(52)
of

suggests

bud

dominance

to

a

winter
this

sprouting.
in

dormancy

may

be

low

Beasley

(8)

Johnsongrass

rhizomes.

17

When rhizome

apexes were

removed,

shoot extension

from the

axillary buds increased from the proximal to the distal end
of

the

growth

rhizome.
is

With

an

significantly

intact

less.

shoot

Hull

apex,

(33)

axillary

obtained

results using 3 and 6 node rhizome pieces.

bud

similar

Germination of

the axillary bud closest to the apex was increased when the
apical bud was removed.

McWhorter

rhizome

as

buds

pieces.

increased

(45) found germination of

rhizomes

were

cut

into

smaller

Anderson's results also indicated more shoots were

produced

from

segmented

than

intact

rhizome

pieces

(4) .

Length of the primary rhizome also affects early vigor and
seasonal

plant

extension

after

growth.

Beasley

5 to

days

20

from larger single node
leaves,

(8)

of

growth

segments.

number of tillers,

found
in

greater
a mist

Plant height,

and fresh weights

shoot

chamber

number of

of shoots and

secondary rhizomes increased significantly as the length of
rhizome
Longer

pieces

increased

rhizomes

pieces

from
also

2.5

cm

produced

to

10

cm

to

secondary

25

cm.

rhizomes

sooner than shorter rhizome pieces.

Seed Germination and Dormancy

Seed dormancy and shattering are characteristics which
influence

both

infestation.

the

invasiveness

and

longevity

of

a

weed

Johnsongrass produces a large number of seeds

18

and

exhibits

ecotype.
a

varying

McWhorter

study

degrees

(43)

the

Johnsongrass

growth

presence

reduce

of

tannin

permeability

and

ecotypes.

dormant when first mature.
the

shattering

with

(64)
an

McWhorter

This

in

the

dormancy

seed
is

after

ripening

period

(63)

examined

the effects

dormancy

varied

among

of

ecotypes.

obtained

after

pre-chilling
of

the addition of 0.2% KNO^.
or

at

the

germination.

end
This

of

seed

55
is

14

at

which

overcome

after

Taylorson and
from 7% to 29%

days.

Taylorson

of temperature,

and KNO^ on the germination of 44 ecotypes.

temperatures

of

coat

(52) .

found an increase in germination

alternating

on

This dormancy is in part due to

compounds

(9) .

development

Johnsongrass

storing 4-5 months at room temperature
Brown

depending

found 1% to 73% seed shattering in

investigating

different

of

Highest
IOC

24/40C,

and

light,

They found that
germination

for

20

days,

continuous

light,

was
with
and

Exposure to far red light during

the

chilling

inhibition

treatment

inhibits

can be partially overcome by

exposure to red light indicating phytochrome involvement in
the

germination

longevity

is

infestation.

also

process
important

of
in

Egley and Chandler

Johnsongrass
the

(62) .

persistence

of

Seed
a weed

(22) found 50% viability of

Johnsongrass seed after burial for 2.5 years at depths of 8,
24, and 38 cm.

19

McWhorter

(45)

found

emergence

of

Johnsongrass

seed

decreased with increasing depth of burial and was lower in a
clay soil than a fine sandy loam.

Holm et al.

(28) reported

most seedlings arise from seed in the upper 7 cm of soil but
can arise from seeds at depths of up to 15 cm.

Morphological Variation of Johnsongrass Ecotypes

A number of studies have been conducted to investigate
morphological variation among Johnsongrass ecotypes.
and Costin
of

a

(7) describe an ecotype as a genotypical variant

species

habitat.

which

Burt

selection

Beadle

arises

and

is more

as

a

response

Wedderspoon

appropriate

(11)

to

a

suggest

in many

of

these

particular
the

term

studies

as

ecotype is restricted to a variation which has been shown to
be

adaptive

however,

to

a

particular

ecosystem.

1971,

is

feasible,

that ecotypes of Johnsongrass have developed as a

response to northward migration.
seldom

It

reported

to

overwintering

Presently,

overwinter
was

winterhardy

In 1926,

north

reported

ecotypes

of

at

have

Johnsongrass was

38°N

40°N
been

latitude.
latitude

reported

north as 43°N latitude in Ontario and New York state
Burt
selections

(10),
from

working
4

with

different

12

different

regions

of

the

In
(11) .

as

far

(66).

Johnsongrass
U.S.,

found

selections from more southern latitudes flowered later than

20

northern
similar
from
The

selections.
results

Maryland

in

and

southern

Wedderspoon

a

study

a

and

involving

southern

selection

(67)

a northern

selection

flowered

Burt

from

found

selection

Mississippi.

later

and

yielded

significantly greater root, rhizome, and total fresh weight.
In

addition,

the

northern

selection

exhibited

susceptibility to the herbicide dalapon.
involving

period

these same selections, Burt and Wedderspoon

(11)

found that

all

southern

selections

selection

Rhizome

production

greater

for

comparing

of

the

the

selections,

temperature

In a second study
dark

20C

effects

most

and

at

the

the

grew

equally,

produced
and

the

southern

and

total

total
stem

selection

morphology

McWhorter

more

of

6

Jordan

however,

at

35C

fresh

number
35C.

found

the

weight.

were
In

different
(49)

at

on

a

also
study

Johnsongrass
variations

in

several characteristics

including the number of primary and

secondary

height,

earlier

culms,
study

plant

involving

and

rhizome

morphological

number.

variation

In
of

an
55

different Johnsongrass selections as well as 3 selections of
S.

almum, McWhorter

(43)

found

differences

in

length

and

width of leaf blades, plant height, culm density, and floret
production.
density

and

Johnsongrass.

S.

almum produced

lateral
In

growth
a

taller plants
were

separate

less
study

although culm
than

that

involving

of
the

susceptibility of these selections to the herbicide dalapon,

21

McWhorter

(42)

and Tucker
dalapon
Rogers

found wide variation in responses.

(24)

among
(34)

Hamilton

also found differences in susceptibility to
five

selections

reported

rhizomes

from

Arizona.

obtained

Ingle

from

a

and

Michigan

selection produced greater growth at low temperatures than a
selection

from Indiana.

comparing

overwintering

Warwick and Black
selections

(66)

in a study

from Ontario,

Ohio,

and

New York and non-overwintering selections from Ontario found
non-overwintering

selections

were

taller,

had

wider

culms

and leaves, larger seeds and inflorescence, greater rates of
germination,
growth.

larger seedlings, and greater rates of seedling

Chernicky

selection

of

and

sorghum

to

Slife
a

(12)

selection

compared
of

an

Illinois

Johnsongrass

from

Tennessee and found the Illinois selection to be taller with
wider

leaf

selection
determined

blades

also

than

produced

that

the

Johnsongrass.
more

Illinois

rhizomes
sorghum

The
per

strain

Tennessee

plant.
more

They
closely

resembled JS. almum than Johnsongrass.

Johnsongrass Control

Johnsongrass

is

control is essential
et al.

a

highly

competitive

species

for successful crop production.

and
Ahmed

(3) found yield reductions of up to 36% in sugarcane

heavily infested with Johnsongrass while Williams and Hayes

22

(68)

reported

soybean

heavily

infested

ability,

several

yield

reductions

fields.
studies

In

addition

decreased
Soybean

as

to

88%

in

competitive

the presence

of

leaves and rhizomes.

found soybean seedling dry weights were

percent

weights

rhizomes

increased.

Horowitz and Friedman

(32)

reported

barley

Rice

inhibition
(1)

decreased

soil

watered using rhizome extracts.

and

also

the

were

similar

were

in

plants

Wahab

dry

(39)

up
to

have demonstrated

allelopathic compounds in Johnsongrass
Lolas and Coble

of

of

reported

that

when

seedlings.

decaying

Abdul-

Johnsongrass

leaves or rhizomes in the soil inhibited the germination and
development
acid,

of

several

p-coumaric

acid,

weed
and

species

studied.

Chlorogenic

p-hydroxybenzaldehyde

were

the

main plant inhibitors present in leaf and rhizome extracts.
Several
control

strategies

of

have

Johnsongrass

been

in

both

situations.

In non-crop areas,

may be

used

to prevent

growth

as

well

found

a

(46)

heavily

the

surface
summer

winter

99%

infested

intervals.
soil

as

seed production
shoots

reduction

in

rhizome

area

well

was

tillage

they
as

Hauser

are

tilled
brings
exposed

freezing
and

for

and

the

non-crop

repeated mowings or tillage

of

where

months.

crop

regrowth

Repeated

as

investigated

six

and

(9, 46).

McWhorter
when

times

2

at

pieces

desiccation

temperatures

Thompson

rhizome

production

rhizome
to

reduce

(26)

to

a

week
the

during

through

the

obtained

88%

23

Johnsongrass control in a non-crop area using the herbicide
dalapon

(2,2-dichloropropionic acid) at 5.6 kg/ha applied as

a split application of 2.8 kg/ha each.
of

5.6

rates

kg/ha

of

did

8.4

provide

adequate

or

greater

applied

application

Johnsongrass
herbicide

not

kg/ha

or sequential

A single application

control.

provided

More

glyphosate

control.
as

either

greater

recently

Dalapon

the

a

single

than

90%

non-selective

(N-(phosphonomethyl)glycine)

has

been

used extensively for Johnsongrass control in non-crop areas.
Baird and Upchurch
which

they

(5) reported on four separate studies in

obtained

greater

than

90% control

with

the

isopropylamine salt of glyphosate at rates of 1.12 kg/ha or
more.

Parochetti et al.

(55) reported significantly greater

control when glyphosate was applied when Johnsongrass was in
the

boot

to

head

stage

height.

When applied

was

or

90%

more,

greater

however,

rather

than

when

45

to

60

at the earlier growth stage,
at

control

glyphosate
diminished

rates of

as the

cm

control

1.12 kg/ha

11 weeks after treatment control was less

70%

treatments.

When

applied at

or

season progressed

and at 8 to
for all

in

the boot

than

to head

stage most treatments provided greater than 90% control at 9
weeks after
adequate

treatment.

Johnsongrass

Although the
control

they

above options provide
necessitate

removal

of

the land from crop production for a season which represents
a potential loss of income for the grower.

Control options

24

which allow the land to remain in production
more

attractive

to

the

grower

and

many

are therefore

such

options

do

as well

as

exist.
Both

herbicidal

combinations

of

these

Johnsongrass

in

corn

treatments

and

practices

have

and

tillage
been

soybeans.

used

McWhorter

to

control

and

Hartwig

(48) obtained 90% Johnsongrass control following 10 discings
prior to planting
incorporated
when

When

treatment

application

preparation

soybeans.

and

was

at

Dalapon applied as a preplant
4.4

kg/ha

proceeded

by

provided

two

discings

followed by one discing

treatment

was

increased

to

86%.

glyphosate

at a rate

followed

by

Crawford and
of

1.68

5

70%

control

for

field

for incorporation.

discings,

Rogers

control

(15)

was

applied

kg/ha to Johnsongrass

2 to 4

feet tall 7, 14, and 28 days prior to field preparation and
soybean planting and obtained control of 86%,
respectively,

one

month

kg/ha provided only 65%

after

planting.

control.

80%, and 81%,

Dalapon

at

Connell and Derting

5.6
(14)

investigated the use of glyphosate at rates of 0.56 to 5.6
kg/ha

as

a

preplant

different tillage

application

systems.

Glyphosate

and above provided acceptable
rhizome
control

Johnsongrass
diminished

reinfestation

by

new

in

soybeans
rates

control of both

using

of

three

1.12 kg/ha

seedling and

25

days

after

treatment, however,

as

the

season

progressed

Johnsongrass

seedlings.

due

Season

to
long

25

control

was

treatments,

increased
however,

with

addition

soybean

stand

of

post-directed

reduction

occurred.

McWhorter

(44) also reported significant soybean injury when

applying

glyphosate

application

at

as

either

of

0.56

rates

an

to

overhead

2.24

or

kg/ha.

direct

Dale

(16)

employed the rope wick applicator as a method of selectively
applying

glyphosate

soybeans.
provided

for

Glyphosate
92% control

a

preplant

applications

i n . emerged

0.1 kg/ha each time

at crop maturity with no visible crop
control when glyphosate was

broadcast

of

control

applied twice at

injury compared to 51%
as

Johnsongrass

spray

glyphosate

at

at

the

2.2

kg/ha.

proper

stage

applied
Preplant

of

growth

often necessitate delays in soybean planting which may cause
yield

loss.

Preplant

treatments

of

glyphosate

are

more

difficult in the northern range of Johnsongrass infestations
due

to

the

cooler

temperatures

which

prevent

plants

from

reaching the proper stage for glyphosate applications until
well

past

the

optimum

soybeans.

Herbicide

control

Johnsongrass

of

planting

treatments
in

the

date

for

which
growing

both

provide
crop

are

corn

and

selective
therefore

attractive options to growers.
Several

selective

herbicides

Johnsongrass control in soybeans.
trifluralin

are

available

Parochetti

(54)

for

compared

(2,6-dinitro-N,N-dipropyl-4-(trifluoromethyl)

benzenamine), nitralin

(4-(methylsulfonyl)-2,6-dinitro-n,n-

26

dipropylanaline),
carbamothioate)

and

dalapon

applied

Dalapon

provided

1.12,
as

and 3.36 kg/ha,

of

dipropylthio-

respectively,

a

preplow

application

75%

control

compared

incorporated

application

(S-propyl

applied as preplant incorporated treatments

at rates of 1.12,

preplant

vernolate

treatments.

dalapon

incorporated treatment,

was

to

5.7

44%

kg/ha.
for

the

When

a

preplow

by

a

preplant

increased

to

followed

control was

at

with

85%.

The

greatest control was obtained from a preplow application of
dalapon followed by trifluralin preplant incorporated.

This

treatment provided 89% Johnsongrass control.

(47)

investigated
efficacy

several

in

Trifluralin

dinitroanaline

controlling

at

the

normal

McWhorter

herbicides

Johnsongrass
use

provide acceptable control.

rate

of

for

in

1.1

the

soybeans.

kg/ha

did

not

At twice this rate control was

88% or more in 4 of the 6 experiments reported.
Recently,

several

postemergence

introduced which provide
in

soybeans

these

are

as well

excellent

as many

fluazifop

herbicides

control

have

been

of Johnsongrass

other broadleaf

crops.

Among

{(+)-2-[4-[(5-(trifluoromethyl)-2-

pyridinyl)oxy]phenoxy]propanoic

acid},

sethoxydim

{2-

[1-(ethoxyimino)butyl]- 5 - [ 2 - (ethylthio)propyl]-3-hydroxy-2cyclohexen-l-one}, quizalofop
oxy]phenoxyl]propionic

acid),

(2-[4-(6-chloro-2-quinoxalinyl)
and

haloxyfop

(2— [4— [ [3—

chloro-5-(triflouromethyl)-2-pyridinyl]oxy]phenoxy]propanoic

27

acid).
to

Banks and Tripp

30-40

soybeans

cm
at

tall

Johnsongrass

rates

of

0.3

provided 100% control,
with

the

(6) applied sethoxydim and fluazifop

exception

and

26

0.6

days

after

kg/ha.

All

planting
treatments

both 32 and 110 days after treatment

of

sethoxydim

applied

at

0.3

kg/ha.

Control with this treatment was 83 and 92%, 32 and 110 days
after treatment,

respectively.

increased

second

later.

by

a

Abernathy

rhizome

application

al.

Johnsongrass

fluazifop

than

Colby et al.
at

et

0.28

Control with sethoxydim was

(2)

14

0.3

obtained

months

sethoxydim.

of

Rates

kg/ha

greater

after
used

28

control

treatment
were

days

not

of

from

stated.

(13) found sequential applications of fluazifop

kg/ha

controlled

regrowth

from

rhizomes

and

substantially reduced regrowth the year following treatment.
Duray and Kapusta
herbicides

for

(21)

compared several postemergence grass

Johnsongrass

Quizalofop,

sethoxydim,

Johnsongrass

control when

cm in height.

and

control

fluazifop

in

provided

37 to

Control decreased at fluazifop rates of
however,

application at these rates improved control.

62
.15

a second

Langemeier and

(37) compared control of 30 to 50 cm tall Johnsongrass

obtained from fluazifop,
of

excellent

applied to Johnsongrass

kg/ha and sethoxydim rates of 0.22 kg/ha,

Witt

soybeans.

0.2,

Kentucky.

0.1,

and

Control

haloxyfop,

0.2 kg/ha,

and sethoxydim at rates

respectively,

at two

8 weeks after treatment was

87,

sites
91,

in
and

28

73% for fluazifop,

haloxyfop,

and sethoxydim,

respectively,

when averaged over both sites and both years of the study.
Patterson

et

al.

(56)

reported

excellent

control

of

many

perennial grasses including Johnsongrass using haloxyfop at
rates of 0.07 to 0.2 kg/ha.

Meninato

(51) obtained greater

than 90% control of 37 to 62 cm tall Johnsongrass haloxyfop
rates of 0.2 to 0.28 kg/ha.
no

significant

Ready and Wilkerson

difference

in

control

of

a

(57)

found

selection

of

Johnsongrass from California compared to that of a selection
from North Carolina using fluazifop.
Selective
more

control

difficult.

thiocarbamate

of

Johnsongrass

Preplant

herbicides

carbamothioate) ,

or

in

incorporated

such

butylate

as

EPTC

(£3-ethyl

corn

has

proven

applications
(£-ethyl

of

dipropyl

bis (2-methylpropyl)

carbamothioate)

have been effective in controlling seedling

Johnsongrass,

however,

suppressed.

rhizome

Hicks and Fletchall

Johnsongrass
(27)

is

only

reported EPTC applied

at rates of 3.36 kg/ha prevented the emergence of seedlings
and

severely

arising

retarded

from

the

rhizomes.

Johnsongrass

plants

application,

however,

were

kg/ha

4 weeks
butylate

for

observed

Roeth

after

elongation

at

(58)

reported
after

consecutive

of

shoots

reductions

three

evaluations

planting

two

and

Significant

later

season long control.
control

growth

weeks

showed
81%

after

inadequate

Johnsongrass

applications
years.

in

of

4.5

Control

at

29

harvest
manner

was

reduced

at 3.4

to

57%.

kg/ha provided

EPTC
91%

applied

control

application but only 57% at harvest.
reported

that

corn

infested

with

Johnsongrass

such as cotton
opportunity
measures.

could

be

for

employment

Currently

the

most

of

similar

4 weeks

successfully

rotated

[Gossypium hirsutum

a

after

Dale and Chandler

grown

when

at

in

with

(L.)]
more

(17)

on

other

land
crops

which provided an
effective

effective

and

long

control
lasting

control measures

for Johnsongrass in field crops consist of

combinations

tillage,

selective
selective

of

pre

and

placement

crop

rotations,

postemergence
and

spot

herbicides such as glyphosate.

and

herbicides

treatment

with

the
as

use
well

of
as

non-selective

Figure 1

The distribution of Johnsongrass in the United
States.
Dots indicate area of greatest economic
importance.

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33

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Johnson­

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34

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35

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36

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Johnsongrass
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CHAPTER TWO

CHARACTERIZATION OF MORPHOLOGICAL VARIATION OF WEEDY
JOHNSONGRASS

[SORGHUM HALEPENSE

(L.) P E R S .]

POPULATIONS IN MICHIGAN

ABSTRACT

In

recent

years,

reports

halepense

(L.)

Pers.]

increased.

This

increasing

be

the

result

tolerant

of

of

the

Johnsongrass

infestations
occurrence

development
cool

of

soil

of

in
of

Michigan

have

Johnsongrass

may

ecotypes

temperatures

[Sorghum

which

are

more

characteristic

of

northern climates.
In

order

Michigan,

to

characterize

morphology

and

Johnsongrass
dry

matter

overwintering

and

non-overwintering

were

with

that

compared

Ontario,

New

York,

non-overwintering
well

as

of

Ohio,

populations

a population

of

S.

and

from Ontario

almum

in

production

of

Michigan

overwintering
Tennessee,

populations

(Parodi)

populations

populations

from

Mississippi
and

Illinois

and
as

from Minnesota.

Distinct differences existed between S. almum and selections

37

38

of S.

halepense with

emergence,

taller

circumference,
flowering.

almum

plants,

fewer

S.

S.

almum

having

wider

larger

leaves,

leaves/culm,
also

exhibited

and

seeds,

faster

greater
fewer

greater

culm

days

crown,

shoot,

and total dry weight while rhizome weight was greater for
halepense.

In

selections

were

overwintering

all

cases

similar

the

to

selections

S.

were

non-overwintering
almum
similar

while
to

S.

Michigan

those
S.

to

of

the

halepense.

These results suggest two distinct sorghum species exist as
weed

problems

in Michigan,

an

overwintering

ecotype

halepense and a non-overwintering ecotype of S. a l m u m .

of

S.

INTRODUCTION

Johnsongrass
fied in the
(13)

[Sorghum halepense

consisting

the
of

section

in two

diploid

in this

(2n=40)

section.

section into a single

with two subspecies,
the

cultivated

relatives,

is classi­

species

Arundinaceae,

and

species.

Halepensia,

Snowden described

DeWet and Huckaby

species,

Snowden

S. bicolor

(5)

divided

(L.)

Moench,

bicolor ssp. bicolor which contains

S.

sorghums,

companion

weeds,

and

semi-wild

and S. bicolor ssp. halepense which contains two

morphologically
tropical

subsections;

(2n=20)

consisting of tetraploid

the

Pers.]

sorghum section of the genus Sorghum.

divided

52 species

(L.)

distinct

ecotype.

The

complexes,

a

Mediterranean

Mediterranean
ecotype

and

consists

a
of

small plants with narrow leaves and extends from Asia Minor
to West Pakistan where

it is replaced by a larger and more

robust tropical ecotype which extends to southern India.

It

is

to

the

have

smaller Mediterranean

been

referred

introduced
to

introgression
sorghum

has

as
of
been

into

ecotype which

the

Johnsongrass
S.

halepense

described

as

39

new

world

(10).
with
S.

an

In

is believed
and

is

Argentina,

unknown

almum

commonly

(11) .

an

cultivated
S.

almum

40

resembles
somatic

halepense

S.

chromosomes

in

being

(4),

rhizomatous

however,

it

and

having

differs

in

40

having

taller, thicker stems, broader leaves, and shorter rhizomes.
Simon

(12)

has prepared a key in which he distinguishes S.

almum

from

the

tropical

and

Mediterranean

ecotypes

of

S.

halepense as having larger sessile spikelets, greater degree
of branching in the panicle,

as well as shorter and thicker

rhizomes.
Considerable
Johnsongrass

morphological

populations

from

variation

different

exists

among

locations.

These

variations may arise as a result of hybridization with other
sorghum species
habitat.

(6, 7) , or as an adaptation to a particular

Burt

and

Wedder spoon

(2)

suggest

the

term

selection to be applicable to populations showing variation
as a result of hybridization while the term ecotype is more
appropriate

when

describing

logical differences
In

1926,

north

of

exhibiting morpho­

in response to a particular ecosystem.

Johnsongrass
38 °N

populations

was

latitude.

seldom
In

1971,

were reported at 4 0 °N latitude

reported

to

overwinter

overwintering

(2) .

ecotypes

Presently, winterhardy

ecotypes have been reported as far north as 4 3 °N latitude in
Ontario and New York state

(14).

It is feasible, therefore,

that ecotypes of Johnsongrass may have developed as a result
of

the

working

northward
with

12

migration

different

of

this

Johnsongrass

species.

Burt

populations

(1) ,

from

4

41

different

regions

of

the

U.S.,

found

selections

from more

southern latitudes flowered later than northern populations.
Wedderspoon

and Burt

(16)

found similar results

in a study

involving a northern population from Maryland and a southern
population

from

flowered

later

rhizome,

and

involving

the

Mississippi.
and

The

yielded

total

fresh

effects

of

southern

significantly
weight.

In

Burt and Wedderspoon

at

grew

all

southern

selections

selection

Rhizome production
for

the

southern

produced
and total

selection

rhizomes

obtained

produced

greater

growth

from

Indiana.

second

study

from
at

a

at

and

Michigan

populations which overwinter in Ontario,

the

also greater

and

Black

35C

weight.

Rogers

than

(14)

Ohio,

(8)

population

low temperatures

Warwick

on

found that

fresh

stem number were
35C. Ingle

period

(2)

however,

more total

at

reported

population

equally,

root,

dark

these same populations,
20C

greater

a

temperature and

population

a

compared

and New York

with non-overwintering populations from Ontario.

They found

that the non-overwintering population were taller, had wider
culms

and

leaves,

larger

seeds

and

inflorescence,

greater

germination, larger seedlings, and greater rates of seedling
growth.

Warwick et al.

populations
of

S.

(15)

suggest

the non-overwintering

from Ontario may represent an introgressed form

halepense

with

population possesses

a

the

cultivated sorghum.
larger,

more

robust

While

this

growth traits

42

of S.

almum and the

tropical

ecotype

of S.

halepense, the

sessile spikelet size and seed color are similar to
as

described

by

Simon

(12).

Chernicky

and

S.

almum

Slife

(3)

compared a sorghum population from Illinois to a population
of

Johnsongrass

population

to

Johnsongrass.
per

from

panicle

determined

be

taller

The

Illinois

and
that

resembled

Tennessee.

fewer

with

found

wider

leaf

population

rhizomes

the

They

than

Illinois

the

blades

than

produced more

seeds

Johnsongrass.

population

more

They
closely

almum than S. halepense.

Although not a serious problem in the past,
Johnsongrass

as

increasing.

The

compare

Illinois

a

weed

problem

objective

morphological

of

the

in

Michigan

present

characteristics

of

reports of
have

study
weedy

been

was

to

sorghum

populations in Michigan with those of populations from other
locations in the eastern U.S., and determine if the Michigan
populations possess

distinct morphological

characteristics,

and if these characteristics are a result of hybridization,
ecotypical

adaptation,

species into the area.
populations
These

of

or

Mississippi,

Johnsongrass

populations
and

separate

introduction

of

the

Morphological characteristics of two

characteristics

overwintering

a

Canada

in

were
from
and

Michigan

were

determined.

compared

with

those

New

Ohio,

Tennessee,

York,

non-overwintering

of

populations

43

from Illinois and Canada as well as a selection of
from Minnesota.

almum

MATERIALS AND METHODS

Ten

Johnsongrass

different

locations

selections
in

the

were

eastern

obtained

U.S.

and

from
Canada.

Overwintering selections were obtained from Ohio, New York,
Mississippi,

Tennessee,

County,

Michigan.

obtained

from

County,

Illinois,

included

County,

Ontario,

Non-overwintering

Michigan.

was also

Brant

A

Essex

selections

County,

selection

of

S.

and Berrien

Ontario,

and

were
Eaton

almum

from Minnesota

for comparative purposes.

Seeds of each

selection were planted in individual peat pots and placed in
a

greenhouse

photoperiod.

maintained
After

two

at

25C

weeks

±

(May

5C
15,

with
1984

a
and

16

hour

May

16,

1985), pots were thinned to one plant per pot and placed in
bushel

baskets

filled

soil, sand, peat)

with

greenhouse

fertilized

once

a

week

with

in a randomized
each

(1:1:1

Plants were watered daily

containing 640 ppm N, P 2° 5 ' and K 2°*

of

soil

and placed outdoors in an area bordered by

greenhouses in East Lansing, MI.
and

potting

100

ml

of

a

solution

Baskets were arranged

complete block design with 10 replications
2
selection, one basket/1.5 m .
Growth parameters

measured are shown in Table 1.

44

45

Plants

were

harvested

Characters

8-14

were

Characters

16-18

were

prior

dry

to

22

determined
determined

weight

weeks
just

after

prior

to

sowing.
harvest.

immediately after harvest

determinations.

Dry

weights

were

obtained by drying the plant material for 48 hours at 140C.
Characters

1-3

determinations.
analyzed

using

and 19 were determined
Data

from 1984

analysis

of

following dry weight

and 1985 were

variance

combined and

techniques

separated using Duncans Multiple Range Test.

and

means

46

Table 1 .

Growth parameters measured.

I.

Seed
1.
2.
3.
4.
5.
6.
7.

and seedling characteristics:
Weight of 25 seeds (g)
Seed length (mm)
Seed width (mm)
Days to emergence (days)
Height 1 week after emergence (cm)
Height 2 weeks after emergence (cm)
Height 4 weeks after emergence (cm)

II.

Morphological characteristics (vegetative):
8. Leaf width —
fourth leaf, main culm (cm)
9.
Leaf length — fourth leaf, main culm (cm)
10.
Leaf number — main culm (no)
11.
Branch number — main culm (no)
12.
Node number — main culm (no)
13.
Stem circumference — fifth internode, main culm
(cm)
14.
Number of tillers (no)
15.
Plant height at flowering (cm)

III. Morphological characteristics (reproductive);
16.
Seedhead length (cm)
17.
Number of whorls/seedhead — main culm (no)
18.
Number of branches/whorl — main culm (no)
19.
Number of seeds/plant (no)
20.
Number of days from sowing to flowering (days)
IV.

Dry w e i g h t s ;
21.
Total weights (g)
22.
Rhizome weights (g)
23.
Seed weights (g)
24.
Root weights (g)
25.
Crown weights (g)
26.
Shoot weights (g)
27.
Reproductive weights (g)
28.
Vegetative weights (g)
29.
Above ground weights (g)
30.
Below ground weights (g)

V.

Dry
31.
32.
33.
34.
35.
36.
37.
38.
39.

weight allocati o n :
Dry weight to rhizomes (%)
Dry weight to seed (%)
Dry weight to roots (%)
Dry weight to crown (%)
Dry weight to shoot (%)
Dry weight to vegetative tissue (%)
Dry weight to reproductive tissue (%)
Dry weight to above ground tissue (%)
Dry weight to below ground tissue (%)

RESULTS AND DISCUSSION

Seed and Seedling Characteristics

Distinct
germination,

differences
and

seedling

existed

in

seed

growth between

size,

weight,

overwintering

non-overwintering selections in this study

(Table 2).

and

Seeds

of non-overwintering selections were both larger and heavier
than those of overwintering selections.

In addition,

these

seeds exhibited faster germination and seedlings from these
seeds

were

results
(14)

are

taller
in

reporting

than

overwintering

agreement
on

with

those

selections.

of

morphological

Warwick
studies

These

and

Black

comparing

overwintering and non-overwintering populations from Canada.
One of each of these populations is included in the present
study

with

similar

results.

Chernicky

and

Slife

(3)

comparing an Illinois sorghum selection to a selection of £>.
halepense

from Tennessee

determined

the

Illinois

selection

more closely resembled S. almum than S. halepense.
therefore,

of

interest

to

compare

the

two

It is,
Michigan

selections in this study with both £3. almum and £5. halepense
using

the

S.

halepense

selection

47

from

Tennessee

for

48

comparative

purposes.

In

overwintering selection
weight

of

0.14

g/25

non-overwintering

case

of

seed

weight,

the

from Berrien County, Michigan had a

seeds

compared

selection

Comparing

these

weights

selection

of

halepense

S.

the

from

with

with

Eaton

those

from

0.27 g

County,

of

S.

Tennessee,

for

Michigan.

almum
it

the

is

and

a

apparent

that the non-overwintering type compares most favorably with
that of
more

S.

almum

similar

weight

of

to

the

the

significantly
results

(0.21 g)

are

S.

while

the

halepense

non-overwintering
greater

observed

than
upon

that

overwintering
(0.16 g)

Michigan
of

comparison

width, germination, and seedling size.

type

is

although

seed

selection

was

£3.

alm u m .

of

seed

Similar

length

and

These results are in

agreement with Simon

(12)

the sessile

spikelets of S. almum are larger than

(fertile)

and McWhorter

(9) who state that

those of £3. halepense.

Morphological Characteristics

Of

the

measured,

eight

vegetative

morphological

characteristics

significant differences between overwintering and

non-overwintering
leaf

(Vegetative)

number,

flowering while

selections

stem

were

circumference,

there

were

no

observed
and

differences

in

plant
in

leaf

width,

height
leaf

node number, number of branches, or number of tillers

at

length,
(Table

49

3) .

Non-overwintering

leaves,

selections

had

wider

leaves,

fewer

thicker steins, and taller plants than overwintering

selections.
selections
agreement

There
within

with

was

these

those

of

very
two

little

types.

Warwick

variation

These

and

between

results

Black

(14)

are

who

non-overwintering selections from Canada to possess

in

found

similar

characteristics as the non-overwintering populations in this
study.
two

Similar results were observed upon comparison of the

Michigan

selections

Although plants

of S.

with

£3.

almum were

the non-overwintering Michigan
overwintering Michigan

almum

and

S.

h alepense.

significantly taller than

selection,

selection more

in all

closely

cases the

resembled

S.

halepense while the non-overwintering selection resembled £3.
almum.

Morphological Characteristics

Previous
in

studies

inflorescence

whorl,

and

(Reproductive)

(3, 9, 14)

length,

seeds/plant

have

reported

whorls/inflorescence,
between

Johnsongrass

differences
branches/
selections,

however in the current study, no consistent differences were
observed

in

differences

these
were

Non-overwintering

characteristics
observed
selections

only

(Table
in

flowered

later than overwintering selections.

days

4) .

Consistent

to

flowering.

approximately

1 week

50

Dry Weights

Of the dry weights measured,
differences
selections

between
in

all

weight

(Table

lower

rhizome,

higher

seed,

vegetative,

overwintering

characters

5) .

crown,
above

ground

weights.

cases

weights

of

closely

below

(above

between
the

resembled

ground

exhibited

considerable

selections,

in

Michigan

while

and

vegetative),

While

overwintering

root

weights

ground

individual

S3, halepense

and

selections

shoot

existed

most

and

non-overwintering

total weight

Non-overwintering

variation
the

and

except

reproductive,

and

there existed significant

most

selection

weights

of

the

non-overwintering Michigan selection resembled £3. alm u m .
particular
weight

interest

between

overwintering
Tennessee

were

are

these

selections.

Michigan
59

and

differences

rhizome

Rhizome

selection
67 g,

in

and

]3.

respectively,

and

weights

Of

seed

for

halepense

the
from

compared with

8

and 11 g for the non-overwintering Michigan selection and £3.
alm u m .

While

seed

weights

were

significantly

non-overwintering selections overall,

higher

this weight was

for

lower

for the non-overwintering Michigan selection than £3. a l m u m .
This

difference

resulted

in

significantly

reproductive weights for these two selections.

different

Above ground

weights were also effected by this difference although this
could

also be

attributed,

in part,

to

the highly

variable

51

shoot weights
root

weights

observed
were

in this

observed

study.

in

the

Significantly

overwintering

selection and S. halepense from Tennessee.
significantly

lower

below

overwintering Michigan

ground

selection

lower

Michigan

This resulted in

weights

relative

for

to S.

the

halepense.

Although there was no difference in total weight between the
overwintering and non-overwintering selections, S. almum did
produce

significantly

Michigan

selection

greater

or

the

dry
£3.

weight

than

halepense

either

selection

the
from

Tennessee.

Dry Weight Allocation

There

were

allocation

significant

between

differences

overwintering

and

in

dry

weight

non-overwintering

selections in all cases except percent dry weight allocated
to

crown

rhizome

tissue

and

dry weight,

to

root

the

tissue

amount

(Table

of dry matter

6) .

As

with

allocated

to

rhizomes by the overwintering Michigan selection was similar
to

£3.

halepense

selection was
the

amount

vegetative

of

while

similar
dry

that

to

S.

matter

structures

as

growth.

Although

seed

Michigan

selection

was

of

the

almum.

The

allocated

well

as

weights
lower

above

of

than

to

the
that

non-overwintering
same was

true

for

reproductive

and

and

below

ground

non-overwintering
of

£3.

almum

the

52

amount

of

dry

matter

allocated

to

seed

production

was

similar between these two selections.
The results of this study indicate distinct differences
in

morphology

allocation
sorghum

as

well

between

as

dry

weight

overwintering

selections.

and

Comparison

production

and

non-overwintering

of

the

overwintering

Michigan selection with S. halepense from Tennessee as well
as

from

these

Mississippi

selections

demonstrates

for

many

of

the

the

similarity

parameters

between

measured,

however, differences among these selections as well as other
overwintering

selections

suggest

that

the

Michigan type represents a distinct ecotype of
Similar

comparison

between

the

overwintering
halepense.

S.

non-overwintering

Michigan

selection and S. almum demonstrate the similarities between
these

selections,

seed

weight,

and

non-overwintering
ecotype

of

S.

conclusions

however,
total

dry

Michigan

almum.
on

non-overwintering

differences

type

Warwick

et

comparison
sorghum

weight

do exist
which

suggest

represents
al.

(15)

of

in height,

a

the

distinct

reached

similar

overwintering

selections

from

Ontario,

and

Canada.

Two of these selections have been included in this study and
as

with

the

two

Michigan

selections,

in

overwintering Canadian

selection most

halepense

non-overwintering

closely

while

resembles

the
S.

almum.

Based

most

closely

on the

cases

the

resembles

selections
results

S.

most

of this

53

study

it

sorghum
Based

is

apparent

selections

on

exist

personal

majority

of

that,

as

as

in

weed

observations,

-infestations

in

Ontario,

two

problems

in

it
the

seems

distinct
Michigan.

likely

northern

that

the

counties

in

Michigan, such as Ingham, Montcalm, and Eaton consist of the
non-overwintering

S.

almum,

southern tiers of counties
halepense.

Whether

species

particular

to

this

whereas

infestations

in

consist of the overwintering
is

areas

due
or

to

adaptation

separate

of

the
S.

these

introduction

of

these species to these areas and the practical implications
concerning

control

measures

for

these

subject of the two subsequent chapters.

two

species

is

the

54

T ab le 2 .

Seed w e ig h t and s i z e , days to em ergence, and h e ^ h t 7, 14, and
28 days a f t e r em ergence f o r 10 sorghum s e l e c t i o n s .

S e le c tio n

Wt. o f
25 Seeds

Seed
L ength

Seed
W idth

(g)

(mm)

(mm)

(days)

0.1 4 cd
0.14cd
0 .1 7 c
0 .1 3 d
0 .1 6 c
0 .1 6 c

4 .3 d e
4 . 2def
4 . 8ab
4 . 2ef
4 .3 d e f
4 .I f

1 .8 b
1 .8 b
2.0 b
1 .6 c
1 .9 b
1 .8 b

10.0b
1 3 .0 a
10.0b
10.0b
1 1.0b
6. Oe

4 .8 a
4 .5 a b c
4 . 6abc
4 . 5abc

2 .1 a
1 .9 b
1 .9 b
2 .1 a

4 .3 b

1 .8 b

4 . 6a

2 .0 a

Days to
Emergence

7 Days

P la n t H eig h t
14 Days 28 Days
(cm)

O v e rw in te rin g
M ichigan
O n ta rio
New York
Ohio
T ennessee
M is s is s ip p i

14b
7b
15b
15b
17b
21a

18c
13d
18c
18c
19c
31a

31b
30b
36b
42a
35b
35b

22a
21a
23a
21a

32a
25b
29ab
34a

42a
44a
45a
43a

1 0 .0 a

15b

20b

35b

7.2 b

22a

30a

43a

N o n-O verw intering
M ichigan
O n ta rio
Illin o is
S . almum

0 .2 7 a
0.20b
0 .1 7 c
0.21b

6 .0 e
9. Ocd
8. Od
6. Oe

Type Means
O v e rw in te rin g 0.15b
N on-overw in­
te rin g
0 .2 1 a

aMeans w ith in a column fo llo w e d by th e same l e t t e r a r e n o t s i g n i f i c a n t l y
d i f f e r e n t a t th e 0.5% l e v e l a s d e term in e d by Duncans M u ltip le Range T e s t.

T able 3 .

Leaf w id th , l e a f le n g th , stem c irc u m fe re n c e ,
t i l l e r s o f 10 sorghum s e le c t io n s .

S e le c tio n

p la n t h e ig h t, number o f le a v e s , b ra n c h e s , n o d es, and

Number
of
Nodes

Number
of
T ille rs

Stem
C ircum ference

H eight
at
Flow ering

(no)

(no)

(cm)

(m)

3 . 2ab
4 .1 a
3 . 2ab
3 .2ab
3 . 2ab
3 . la b

5 .2 ab
5 .3 ab
5.5ab
5 .2 ab 4 .9 b c
6. 0a

15c
16bc
19abc
19abc
20ab
18bc

3. le d
3 . 3bc
3.0cd
2.9d
3.0cd
3. le d

2.1 c
2 .0 c
2 .1 c
2.1 c
2.0 c
2 .1 c

13e
13de
15bcde
13e

3 .9 a
3 .0 a
2.3b
3 .2 ab

5 .3 ab
4 .3 c
5 .2 ab
5 .6 ab

20ab
20ab
19ab
22a

3 .8 a
3.6ab
3.6ab
3.6ab

2 .4 a
2 .4 a
2.3ab
2.3b

18a
13b

3 .3 a
3 .1 a

5 .3 a
5 .1 a

18a
21a

3.1b
3 .6 a

2.1b
2 .4 a

Leaf
Width

L eaf
Length

Number
o f Leaves

Number o f
B ranches

(cm)

(cm)

(no)

(no)

3 .6 c
3 .7 c
3 .5 c
3 .5 c
3 .2 c
3 .4 c

62a
59a
54a
61a
55a
56a

19ab
19ab
15cde
21a
17bc
17bc

4 . 5ab
4 .2 b
4 .9 a
4 . 7ab

55a
55a
57a
58a

3.5b
4 . 6a

58a
56a

O verw intering
M ichigan
O n tario
New York
Ohio
Tennessee
M is s is s ip p i
N on-O verw intering
M ichigan
O n ta rio
Illin o is
S. almum
Type Means
O verw in terin g
N on-O verw intering

^eans within a column followed by the same letter are not significantly different at the 0.05% as determined by
Duncans Multiple Range Test.

56

T able 4 .

Seedhead le n g th , number o f w h o rls p e r s e e d h e a d , number o f
b ra n c h e s p e r w h o rl, number o f se e d s p e r p lia n t, and number of
days to flo w e rin g f o r 10 sorghum s e l e c t i o n s .

S e le c tio n

Seedhead
L ength

W horls
P e r Seedhead

B ranches
P e r Whorl

Seeds
P e r P la n t

Days to
Flow er

(cm)

(no)

(no)

(xlOO)

(no)

31 ab
31ab
33ab
30ab
31 ab
33ab

9 . 6ab
9 .4 ab
9 . 7ab
1 0 .2ab‘
1 0 .la b
1 0 .8 a

4 .5 a b
3 .4 c
4 .5 a b
3 .9 b c
4 . Obc
3 .8 b c

157ab
114cd
94d
120cd
123c
124c

75bc
78ab
78ab
76bc
78ab
80a

30ab
34a
28b
31ab

9 . 9ab
8 .9 b
9 .2 a b
9.1 b

4 . 2bc
4 .1 b c
4. Obc
5 .3 a

92d
114cd
181a
139bc

71d
72d
71d
72d

4 .0 a
4 .4 a

122a
132a

77a
71b

O v erw in te rin g
M ichigan
O n ta rio
New York
Ohio
T ennessee
M is s is s ip p i
N on-O verw intering
M ichigan
O n ta rio
Illin o is
S . almum
Type Means
O v e rw in te rin g
N o n -o v e rw in te rin g

31a
31a

1 0 .0 a
9 .3 a

^ e a n s w ith in a column fo llo w e d by th e same l e t t e r a re n o t s i g n i f i c a n t l y
d i f f e r e n t a t th e 0.05% l e v e l a s d e term in e d by Duncans M u ltip le Range
T e s t.

Table 5. Rhizome, seed, root, crown, shoot, reproductive, vegetative, above ground, below ground, and total dry
weights of 10 sorghum selections .

S e le c tio n

Above
Ground
Weight

Below
Ground
Weight

(gm)

(gm)

(gm)

144a
126ab
116bc
114bc
146a
133ab

290d
298cd
350ab
321bcd
291d
335abc

301bcd
286cde
289cde
277de
261e
298bcd

134cd
139bc
139bc
157ab
176a
170a

140bcd
149abc
159ab
168a

106c
100c
127ab
128ab

326abc
336abc
347ab
361a

333b
320bc
367a
380a

99e
116de
107e
108e

126b
154a

130a
115b

314b
342a

285b
350a

159a
107b

T o ta l
Weight

Rhizome
Weight

Seed
Weight

Root
Weight

Crown
Weight

Shoot
Weight

R ep ro d u ctiv e V e g e ta tiv e
Weight
Weight

(gm)

(gm)

(gm)

(gm)

(gm)

(gm)

(gm)

435bc
425c
467abc
435bc
437bc
468ab

59ab
63ab
53b
57ab
67a
57ab

87bc
63de
62de
56e
79c
75cd

74d
76d
124a
99bc
108abc
112ab

56e
68bcd
84a
75abc
62de
58de

136cd
123de
129cd
129cd
105e
132cd

432bc
436bc
475ab
489a

8c
9c
8c
11c

97b
91bc
119a
117a

90cd
107abc
98bc
97bc

75abc
80ab
72abc
72abc

444a
458a

59a
9b

70b
106a

99a
98a

67b
75a

O verw in terin g
M ichigan
O n ta rio
New York
Ohio
T ennessee
M is s is s ip p i
N on-O verw intering
M ichigan
O n ta rio
Illin o is
S . almum
Type Mean
O v erw in terin g
N on-O verw intering

^eans within a column followed by the same letter are not significantly different at the 0.05% level as
determined by Duncans Multiple Range Test.

Table 6. Dry weight allocation to rhizomes, seeds, roots, crowns, reproductive, vegetative, above ground, and
below ground tissue of 10 sorghum selections .

S e le c tio n

Rhizome

Seed

Root

Crown

Shoot

R ep ro d u ctiv e

V e g e ta tiv e

Above
Ground

(%)

(%)

(%)

(%)

(%)

(%)

(%)

(%)

(%)

Below
Ground

O v erw intering
M ichigan
O n ta rio
New York
Ohio
T ennessee
M is s is s ip p i

13.7ab
1 4 .9 a
11.5b
1 3 .2ab
1 5 .4 a
12.5ab

19cd
15ef
13f
13f
18cde
16def

17 f
17ef
26a
23abcd
25ab
23abcd

14cd
16abc
18ab
17ab
14cd
12d

34b
35ab
30cd
34bc
27d
34bc

33a
30ab
24cd
26bcd
, 33a
28bc

66d
70cd
7Sab
73abc
66d
71bc

6 2d
67bc
61d
63cd
59d
63cd

31c
32bc
38a
36ab
40a
36ab

1 .9 c
2 .0 c
1 .8 c
2 .2 c

22ab
21bc
25a
24a

21bcde
24abc
20cdef
20def

17 ab
18a
15bc
14cd

37ab
33bc
36ab
34bc

24d
23d
27bcd
26bcd

75a
76a
73abc
73abc

76a
73a
77a
77a

23d
26d
2 2d
22d

1 3 .5 a
2 .0 b

15b
23a

22a
21a

15a
16a

32b
36a

29a
25b

70b
74a

64b
76a

35a
23b

N on-O verw intering
M ichigan
O n ta rio
Illin o is
S. almum
Type Mean
O verw in terin g
N on-O verw intering

3
Means within a column followed by the same letter are not significantly different at the 0.05% level as
determined by Duncans Multiple Range Test.

LITERATURE CITED

1.

Burt, G.W.
1974.
Sci. 22:59-63.

2.

Burt, G.W. and I.M. Wedderspoon.
1971.
Growth of
Johnsongrass selections under different temperatures
and dark periods.
Weed Sci. 19:419-423.

3.

Chernicky, J.P. and F.W. Slife.
1985.
strain of Illinois sorghum to Tennessee
Weed Sci. 33:328-332.

4.

Davies,
J.G.
and L.A. Edye.
1959.
Sorghum almum
Parodi-A valuable summer-growing perennial grass.
J.
Aust. Inst. Agri. Sci.
p. 117-127.

5.

DeWet, J.M.J. and J.P.
sorghum bicolor.
II.
Evolution 21:787-802.

6.

Endrizzi,
J.E.1957.
species and hybrids
119:1-10.

7.

Hadley, H.H.
1953.
Cytological relationships between
Sorghum
vulgare
and
S.
halepense.
Agron.
J.
45:139-143.

8.

Ingle, M. and
B.J. Rogers.
1961. The growth of a
midwestern strain of Sorghum halepense under controlled
conditions.
Am. J. Bot. 48:392-396.

9.

McWhorter,
C.G.
1971.
Growth and development
Johnsongrass ecotypes.
Weed Sci. 19:141-147.

10.

Adaptation

of

Johnsongrass.

Weed

Comparing a
Johnsongrass.

Huckaby.
1967.
The origin of
Distribution and domestication.

Cytological
studies of
in the Eu-Sorghums.
Bot.

some
Gaz.

of

Monaghan,
N.
1979.
The biology of
Johnsongrass
(Sorghum halepense) . Weed Res. 19:261-267.

59

60

11.

Parodi, L.R.
cultivada en
10:361-372.

1943.
Una neuva especie de Sorghum
la Argentina.
Rizu. Agrent. de Agron.

12.

Simon, B.K.
1979.
Naturalized fodder sorghums in
Queensland,
and their role in shattering in grain
sorghums.
Queens, J. Agri. and Anim. Sci. 36:71-86.

13.

Snowden, J.D.
1936.
The cultivated races of sorghum.
Allard and Sons, London, U.K.
272 pp.

14.

Warwick, S.I. and L.D. Black.
1983.
The biology of
Canadian weeds.
61.
Sorghum halepense (L.) Pers. Can.
J. Plant Sci. 63:997-1014.

15.

Warwick, S.I., B.K. Thompson, and L.D. Black.
1987.
Genecological studies of new-problem weeds in Canada.
I.
Population
variation
in
Sorghum
halepense,
Johnsongrass.
Unpublished.
Biosystematics
Research
Institute and Engineering and Statistical
Research
Institute, Agriculture Canada, C.E.F., Ottawa, Ontario
KlA 0C6.

16.

Wedderspoon, I.M. and
development of three
Sci. 22:319-322.

G.W. Burt.
1974.
Growth and
Johnsongrass selections.
Weed

CHAPTER THREE

EFFECTS OF TEMPERATURES ON THE SEED GERMINATION,
VIABILITY, AND SPROUTING OF RHIZOMES AND FATTY
ACID CONTENT OF SEVERAL SORGHUM SELECTIONS

ABSTRACT

In

recent

halepense

(L.)

increased.

years,
Pers.]

reports
as

a weed

of

Johnsongrass

problem

[Sorghum

in Michigan

have

This apparent spread may, in part, be due to the

development

of

ecotypes

tolerant

to

cold

temperatures.

Experiments were conducted to determine the effects of cold
temperature
rhizome

on

rhizome

viability

of

sprouting,

seed

overwintering

and

germination,

and

non-overwintering

selections from Michigan as well as overwintering selections
from Ontario, New York, Ohio, Tennessee, and Mississippi and
non-overwintering
well

as

a

selections

selection

of

S.

from

Ontario

almum

(Parodi)

and

Illinois

as

from Minnesota.

With the exception of S. a l m u m , non-overwintering selections
exhibited less rhizome sprouting at lower temperatures than
overwintering

selections

but

seed

61

germination was

greater.

62

Rhizome

sprouting

of

S.

almum

was

similar

to

overwintering selections at all temperatures.

that

of

the

Overwintering

of rhizomes was investigated at two locations in Michigan, a
northern location in Montcalm County and a southern location
in Berrien County.
all

selections

southern

Rhizome survival overwinter was poor for

at

location

tolerance.

the

northern

location,

overwintering

types

however,

showed

at

superior

the
cold

Exposure to temperatures of -4C or -7C in growth

chambers killed rhizomes of both Michigan selections as well
as the
5C

selection

had

no

decreased

from Tennessee and S. a l m u m .

effect

on

rhizome

viability

of

the

survival.

Exposure to

Exposure

non-overwintering

to

OC

Michigan

selection and S. almum after 3 days but had no effect of the
overwintering
Tennessee.
membrane

Michigan

selection

or

the

S.

halepense

from

No consistent differences were observed in cell
fatty

acid

saturation

between

overwintering

and

non-overwintering selections to account for the differences
in cold temperature tolerance.

INTRODUCTION

Since the introduction of Johnsongrass into the south­
eastern U.S.
more

in the 1800's

northern

reported

to

latitudes.

overwinter

overwintering

was

(9), it has gradually spread to
In 1926,

north

reported

of

at

Johnsongrass was

38°N

40°N

latitude.

latitude

seldom

In

(2) .

1971,

Present

winterhardy ecotypes have been reported as far north as 43°N
latitude

in

Ontario

studies

have

differences

been
in

Johnsongrass
locations.

and

York

conducted

morphology

selections
Burt

New

state

to

and

from

(16).

determine
growth

northern

Several
possible

patterns
and

of

southern

(1) , working with 12 different selections

from 4 different regions of the U.S.,

found selections from

more southern latitudes flowered later than those from more
northern latitudes.
results
Maryland

in

a

and

study
a

Wedderspoon and Burt
involving

southern

a

(17) found similar

northern

selection

from

selection

from

Mississippi.

The

southern selection flowered later and yielded significantly
greater root, rhizome, and total fresh weight.

In a second

study involving the effects of temperature and dark period
on

these

same

selections,

Burt

63

and

Wedderspoon

(2)

found

64

that at 20C all selections grew equally, however, at 35C the
southern

selection

Rhizome production
for

the

southern

produced
and

total

selection

more

total

fresh

stem number were
at

35C.

Ingle

weight.

also greater

and

Rogers

(7) -

reported that a selection of Johnsongrass from Michigan had
an optimum growth temperature of 21C compared to 27C for a
selection from Mississippi.

Warwick and Black

(16) compared

overwintering

selections

Ontario,

York,

and

Ontario

Johnsongrass

Ohio

and

with

found

non-overwintering

differences

in

Chernicky and Slife

selection

of

found the

Illinois

blades.

sorghum

with

from

morphological

leaf and culm width,

(3) compared an Illinois

Johnsongrass

selection

New

selections

several

characteristics including plant height,
and seed size.

from

to be

from

Tennessee

taller with wider

and
leaf

The Tennessee selection also produced more rhizomes

per plant.
The results of these studies as well as studies by this
author indicate the development of geographical ecotypes of
Johnsongrass
species.
lower

as a result of the northward migration of the

Earlier

flowering and greater rates of growth at

temperatures

are

growing in more northern

obvious

advantages

locations,

however,

for

species

it would

seem

necessary for other adaptations to occur in order to insure
survival of the species at the cooler temperatures common to
the

north

central

region

of

the

U.S.

Among

these

65

adaptations would be greater tolerance of rhizomes

to cold

temperatures

of

rhizomes

which

to

would

overwinter

increase

and

the

the

ability

ability
for

the

rhizomes

sprout and seeds to germinate at lower temperatures.

to

Due to

the relatively recent introduction of Johnsongrass into the
northern regions of the U.S.,
the

possible

ecotypes.
high

presence

of

Johnsongrass

temperature

few studies have investigated

these

rhizomes have been

requirement

for

t

(6)

reported

13.5%,

•

81.5%,

shoot

emergence

optimum

shown

three

northern
to have a

sprouting.

91.5%

germination

Horowitz

Hull

Johnsongrass

Maryland and Mississippi at 35C,

25C,

at

15C,

(5) obtained maximum

Burt and Wedderspoon

of

in

•

and

22.5C, and 30C, respectively.
bud sprouting at 28C.

adaptations

(2) investigated
selections

from

and 20C and found no

differences in emergence rate among selections at any of the
three temperatures.
germination
ecotypes.

Taylorson and McWhorter

differed
Johnsongrass

among

44

rhizomes

different
have

tolerance to freezing temperatures.
(10) , rhizomes
more

than

exposed

4 hours

did

to

survive.

Johnsongrass

shown

very

little

In a study by McWhorter

temperatures

not

(15) found seed

of -3C
Hull

(6)

or

less

also

for

found

rhizomes did not survive exposure to temperatures of -3.5C
or less.

Chernicky and Slife

capacity

of

an

Illinois

(3) compared the overwintering

sorghum

strain

to

that

of

a

Johnsongrass selection from Tennessee and found that 90% of

66

the

rhizomes

winter

from

while

survived.

only

the
5%

Tennessee
of

those

They attributed

from

this

penetration by the rhizomes

selection
the

survived

Illinois

difference

the

strain

to greater

soil

from the Tennessee strain which

enabled them to escape exposure to lethal soil temperatures.
Stoller

(14)

rhizomes

in

a

rhizome

tolerated

burial

temperatures

study
as

found

low

as

quackgrass
-17C

while

Johnsongrass rhizomes were killed at temperatures below -9C.
He

found a higher proportion of unsaturated

fatty acids in

quackgrass rhizomes and suggested this may contribute to the
cold tolerance of quackgrass.
significant

difference

in

He did not,
the

polar

however,

lipids

find a

which

are

important in cell membranes.
Michigan is currently on the northern edge of the range
of

Johnsongrass

in

the

U.S.,

however,

reports

of

Johnsongrass as a weed problem in Michigan fields have been
increasing.
cal

Previous

similarities

from Michigan,
selections

between

Ontario,

from

non-overwintering
to

S.

almum.

studies have demonstrated morphologi­

The

overwintering

New York,

Mississippi
selections

of

selections

and Ohio and S. halepense
and

appeared

objective

sorghum

the

Tennessee
closer

while

in morphology

current

study

was

to

determine if similarities also exist in optimum temperature
for

rhizome

sprouting,

tolerance of these

seed

germination,

selections.

and

Fatty acids

rhizome

changes

cold

in the

67

cell

membrane

phospholipids

of

rhizomes

after

exposure

to

low temperature were also investigated to determine if this
may

be

a

factor

selections.

in

differential

cold

tolerance

of

these

MATERIALS AND METHODS

Rhizomes
were

and

obtained

seeds

from

used

in

Johnsongrass

the

following

selections

experiments

grown

in

Lansing, Michigan during the summer of 1984 and 1985.
of

non-overwintering
Eaton

Johnsongrass

Illinois,

and

County,

selections

from Ontario,

selections

Michigan

New York,

from

and

East
Seeds

Ontario,

overwintering

Tennessee,

Mississippi,

Ohio, and Berrien County, Michigan as well as a selection of
almum from Minnesota were planted in individual peat pots
and placed in a greenhouse maintained at 25 ± 5C with a 16
hour photoperiod.
1985)

After 2 weeks

(May 15,

1984

and May 16,

pots were thinned to one plant per pot and placed in

bushel

baskets

filled

with

greenhouse

potting

soil

(1:1:1

soil, sand, peat) and placed outdoors in an area bordered by
greenhouses in East Lansing, MI.
and

fertilized

once

containing 640 ppm N,

a

week

Plants were watered daily

with

P2®5' an(* K 2°*

100

ml

of

a

solution

Baskets were arranged

in a randomized complete block design with ten replications.
Plants were harvested 22 weeks after planting and seeds and
rhizomes

collected

from

each

plant

and

either

used

immediately or placed in polyethylene bags and stored at 5C

68

69

until used.

Representative rhizome samples were obtained by

first selecting uniform plants of each selection.

Rhizomes

from these plants were then combined and uniform three node
rhizome

sections

selected

for

each

study.

Seeds

obtained in a similar manner with several hundred
each

uniform

plant

from

each

selection

were

seeds of

combined.

Seed

samples were then drawn from this composite sample.

Rhizome Sprouting vs. Temperature

The

optimum

selection
segments

was
2.5

rhizome

determined
cm

deep

germination

temperature

by

3-three

in

greenhouse potting soil

placing

0.5

L

plastic

(1:1:1 soil,

for

node

pots

rhizome

containing

sand, p e a t ) .

The pots

were then placed in growth chambers maintained at 15C,
or

30C

for

2

rhizomes were
each
with

weeks.
removed

selection.
three

the

The
years.

experiments.

end

and percent
experimental

replications,

replication.
successive

The

At

the

2

week

design was

was

reported

node
done
are

in

a

25C,

period,

sprouting determined

3-three

experiment
Means

of

each

for

split

plot

segments

per

each

of

two

averages

of

two

70

Seed Germination v s . Temperature

The

optimum

selection

was

selection

in

seed

germination temperature

determined
a

60

by

15

by
mm

Whatman No.

1 filter paper

dishes

then

were

sealed

placing
petri

and

and

ten

dish

2 ml

for

each

of

each

seeds

containing

5.5

distilled water.

placed

in

total

cm
The

darkness

in

growth chambers maintained at 15C, 20C, 25C, 30C, or 35C for
2

weeks.

At

the

end

of

the
t

removed

and

selection.

percent

2 week

-

period,

plates

germination determined

Prior to the

were

•

for

each

onset of the experiment, seeds were

stored for 4 months at room temperature to allow ample time
for

after

ripening.

Experimental

with ten replications.
two

successive

years.

design

was

a

split

plot

The experiment was done in each of
Means

reported

are

averages

of

two

experiments.

Rhizome Burial Study

Uniform

3-node

rhizome

pieces

of

each

selection

were

placed in nylon mesh bags and buried 10 cm or 20 cm deep in
a

sandy

location)
Michigan
were

loam
or

soil
a

in

sandy

Montcalm
clay

(southern location)

allowed to remain

County,

loam

soil

Michigan
in

Berrien

in mid November.

in the

soil

through

(northern
County,

The rhizomes
the winter

and

71

excavated

in

early

May of

the

following

year.

Rhizomes

which exhibited obvious signs of decay were discarded.

The

remaining rhizomes were planted 2.5 cm deep in 0.5 L plastic
pots
peat)

containing

greenhouse

soil

(1:1:1

soil/

sand,

and placed in a growth chamber maintained at 30C for 2

weeks

at

which

time rhizomes

sprouting determined.
were

potting

not

included

differences
reported

in

are

were

removed

and

percent

Selections from Illinois and New York
in

this

survival
averages

study.

between
of

five

As

the

there

two

were

depths

replications,

2

no

means,
rhizome

pieces/replication.

The experiment was done in each of

two

successive

Means

two

years.

reported

are

averages of

experiments.

Rhizome Temperature Tolerance

Cold
selection

temperature tolerance
from

selections from
well

as

a

Eaton

County,

Tennessee

selection

and

of

of

a

Michigan

Berrien

S.

non-overwintering
and

overwintering

County,

almum

from

Michigan

as

Minnesota

was

determined by placing 3-three node rhizome segments of each
selection

2.5

styrofoam

pots

potting

soil

cm

deep

in

containing

(1:1:1 soil,

20.5

cm

slightly

by

12.5

cm

moistened

sand, p e a t ) .

by

6.0

cm

greenhouse

The pots were

then

placed in growth chambers maintained at -7, -4, 0, or 5C for

72

24, 48, 72, or 96 hours.
t i m e s , pots were
soil

slowly

removed

containing

removed

warmed

and

At the end of the various exposure

to

planted

from
room

2.5

sterilized

the

growth

chambers

temperature.

cm

deep

in

field

soil.

0.5

the

Rhizomes

were

plastic

pots

L

These

and

pots

were

then

placed in a greenhouse maintained at 30C ± 5C for 2 weeks at
which

time

rhizomes

were

removed

determined for each selection.
a

three

factor

factorial

with

and

percent

sprouting

The experimental design was
three

replications,

3-three

node segments constituting one replication.

The experiment

was

Means

done

in

each

of

two

successive

years.

reported

are averages of two experiments.

Cell Membrane Lipid Composition vs. Temperature

The effects of cold temperature exposure on fatty acid
composition of cell membranes phospholipids of rhizomes from
a

non-overwintering

and

overwintering

County,

Michigan

Minnesota
were

was

placed

styrofoam

placed

in

from

Eaton

selections

from

Tennessee

well

as

determined.

2.5

pots

potting soil

as

selection

cm deep

selection

Three
in

containing

(1:1:1 soil,

growth

a

chambers

20.5

slightly
sand,

of

3-node
cm by

S.

Berrien

almum

rhizome
12.5

Michigan

and

from

segments

cm by

moistened

peat).

maintained

County,

6.0

cm

greenhouse

The pots were then
at

0C

or

5C

for

96

73

hours.

At the end the exposure time pots were removed from

the growth chamber and the
to

room

rhizome

temperature
segments

approximately

and

from

the

rhizomes

each

removed.

replication

The

three

cut

into

were

1 cm pieces and a single 20 g sample removed

for analysis.

In

addition

various temperatures,
to

soil was allowed to slowly warm

to

the

rhizomes

exposed

to the

a sample of fresh rhizomes not exposed

low temperature was

also

obtained.

Each

treatment was

replicated three times with three segments per replication.
The

experiment

was

repeated.

Rhizomes

used

in

the

experiment were obtained as previously described.

first

Rhizomes

for the second experiment were obtained from plants grown in
a greenhouse maintained at 30C with a 12 hour photoperiod.
With

this

growth

exception

parameters

differences

were

and

that

were

observed

of

planting

similar.
between

date

No

all

other

morphological

plants

grown

in

the

greenhouse and those grown outdoors and this distinction has
been ignored throughout.
Following
content

was

temperature

determined

treatment

according

to

rhizome
a

fatty

slightly

procedure described by Rivera and Penner

(12).

acid

modified

Plasmalemma

membranes were obtained by homogenizing 20 g rhizome samples
in a Virtis grinder for 90 seconds in 30 ml of an ice-cold
medium
Tricine

consisting
(N-Tris

of

0.26

M

sucrose,

(hydroxy-methyl)

methyl

3

mM

EDTA,

glycine),

50

mM

and

1%

74

(w/v) BSA
The

(Bovine Serum Albumin)

homogenate

was

(fatty acid free)

strained

through

four

(pH 7.8).
layers

of

cheesecloth and centrifuged at 13,000 x g for 15 minutes at
2C.

The

supernatant

centrifuged

at

pellet

then

was

containing

containing

80,000

1 mM

x

g

for

resuspended
MgSO^

and

ethane sulphonic acid)

plasmalemma

30
in

minutes.
2

1 mM

ml

(pH 7.8).

The

20%

Tris-Mes

was

further
resulting

(w/w)

sucrose

(2-N-morpholino-

The suspension was layered

onto a discontinuous sucrose gradient consisting of 28 ml of
45%

(w/w)

sucrose

and

8

of

34%

(pH 7.8).

The gradient tubes were centrifuged for

2

at

x

plasmalemma

were

in

obtained

a

10 minutes.

swinging

from

diluted in deionized water,

mM

the

34%

MgSO^

bucket
to

and

The

Tris-Mes

g

1

sucrose.

solutions

95,000

contained

(w/w)

sucrose

hours

each

ml

1

rotor.

45%

mM

The

interface,

and pelleted at 80,000 x g for

The plasmalemma

samples were held at -15C

for

further analysis.
The

frozen

membrane

samples

were

lyphilized

and

the

lipids extracted according to a modified procedure by Folch
et al.

(4) .

Ten ml of chloroform/methanol

to the

lyphilized tissue

and the

samples were

water bath at 33C for 30 minutes.
(Whatman

No.

4)

into

re-extracted once with

a
5 ml

(2:1)

was

shaken

added
in

a

The extract was filtered

second

tube,

and

the

residue

chloroform/methanol by shaking

in a water bath for 15 minutes.

The filtered extracts were

75

obtained and washed with 0.2 vols of 0.9% NaCl solution in a
tube stirrer for 30 seconds.

After the mixture settled, the

upper phase was discarded and the lower phase washed
with

0.2

vols

of

CHCl^-MeOH-I^O

containing 0.9% NaCl.
was

taken

to

dryness

dissolved in 50
TLC plates
F254.

in

^

band

volume)

at

33C

and

the

residue

The lipids were then applied to

precoated with

M e 2CO-MeCOOH-H20

phospholipid
values

under

The phospholipids were

lipids

by

The lower phase containing the lipids

yl CHCl^.

(20 x 20)

(3:48:37

twice

selected

0.25 mm

separated
(100:2:1)

on

the

silica gel

60

from the remaining
by

basis

volume
of

and

the

published

Rf

(13) was scraped from the plates, extracted with 2 ml

chloroform/methanol followed by 1 ml MeOH and the resultant
solution
methyl

taken
esters

to

dryness

were

under

prepared

procedure of Metcalfe et al.

^

at

33C.

according

(11).

to

Fatty
a

acid

modified

0.5 N methanolic KOH

(1

ml) was added to the dried sample followed by boiling for 5
minutes.

After the tubes had cooled,

1 ml of 14% BF3-MeOH

was added and the sample boiled for an additional 2 minutes.
One drop of saturated NaCl solution was then added and the
methyl esters extracted 3 times with 1 ml hexane each.
extracts
taken

up

were combined,
in

50

composition was

yl

dried

acetone

under
for

determined by

Nj,

GLC

FID

and

analysis.

using

a

1.83

the

The

residue

Fatty

acid

m

2 mm

by

glass column packed with 12% stabilized DEGS on anakrom ABS

76

and

operated

at

identification

190C
and

with

^

as

the

quantification

carrier
was

gas.

performed

Peak
by

comparison with authentic fatty acid methyl ester standards.
- Data was analyzed as a split plot and means separated using
Duncans Multiple Range Test.
two experiments.

Means reported are averages of

RESULTS AND DISCUSSION

Effect of Temperature on Rhizome Sprouting

The

results

difference

of

in

this

study

sprouting

demonstrate

ability

of

a

significant

rhizomes

overwintering and non-overwintering selections.

from

At 15C all

overwintering selections except those from New York and Ohio
exhibited

significantly

non-overwintering

greater

selections

rhizome

except

S.

sprouting
almum

than

all

(Table

1).

Percent sprouting of rhizomes of £3. almum was significantly
greater

than

all

similar

to

that

rhizome

sprouting

temperature

selections

of

was

overwintering

other
the

of
63%

non-overwintering
overwintering

the

selections.

showed

selections.

overwintering

compared

with

At

greater

all

for

and

Average

selections
39%

25C

rhizome

selections

at

the

this
non­

overwintering

sprouting

than

the

non-overwintering selections with the exception of £3. alm u m .
Average

rhizome

overwintering
selections.
rhizome

sprouting

at

this

selections,
At

45%

30C there was no

sprouting

between

any

77

of

temperature was
for

87%

non-overwintering

significant difference
the

for

selections.

in

Average

78

sprouting was 84% for the overwintering selections,
non-overwintering

selections.

The

81% for

overwintering

and

non-overwintering selections from Michigan showed these same
trends

with

the

overwintering

significantly greater
difference at 30C.

with

exhibiting

sprouting at both 15C and

25C and no

Sprouting at 15C, 25C, and 30C was 66%,

91%, and 83%, respectively,
compared

selection

8%,

33%,

for the overwintering selections

and

83%

for

the

non-overwintering

selection.
a

*

•

Due to the morphological similarity of the overwinter­
ing Michigan

selection

Mississippi

and

to

Tennessee

non-overwintering Michigan
interest to compare
these

selections

selections.

the

and

of

the

S.

halepense

similarity

selection to S.

sprouting ability of rhizomes

Sprouting

of

the

all

three

overwintering
These

an

Michigan

results

suggested

selection

support

the

ecotype

temperatures

of

S.

was

less

Michigan

halepense

represented

that

an

while

at

ecotype

of

S.

the

15C

and

non­
25C.

studies which

selection
the

halepense

S.

of

previous morphological

overwintering

from

overwintering Michigan

while

selection

the

a l m u m , it is of

selection was similar to the two selections of
at

of

from

represented

non-overwintering
almum,

however,

comparison of the sprouting ability of rhizomes of the two
Michigan
Contrary

selections
to

with

expectations,

that
the

of

S.

almum

does

non-overwintering

not.

Michigan

79

selection

exhibits

25C

S.

than

significantly

almum

similar to S.

while

the

less

sprouting at

overwintering

15C and

selection

almum at all three temperatures.

is

It appears

that if the two Michigan selections do represent selections
of

£3.

halepense

and

S.

almum#

respectively,

they

are

distinctly different ecotypes.
The

results

demonstrated

of

the

the

previous

greatly

non-overwintering

morphological

reduced

selections

to

capacity

produce

study

of

the

rhizomes.

The

results of the current study suggest that rhizomes produced
by

these

higher

selections

soil

are

less

temperatures

would

result

the

growing

in

for sprouting.

sprouting
season

vigorous

of these

when

the

and

require

much

In Michigan,

this

rhizomes much

later

competitive

in

ability,

particularly, with early planted crops such as corn would be
reduced

relative

to

the

earlier

emerging,

more

vigorous

overwintering selections.

Effect of Temperature on Seed Germination

Although differences

in germination between individual

selections existed, in general, non-overwintering selections
exhibited

significantly

overwintering
and 20C

selections

(Table 2) .

greater
at

the

germination

lower

than

temperatures

of

the
15C

Percent germination at 15C and 20C was

80

45%

and

64%

for

compared to 31%
At

and

temperatures

differences

the
45%

for

above

in

non-overwintering
the

20C

non-overwintering

selections.

exhibited

overwintering
temperatures

greater

and

was

between

20C.

no

sprouting was

germination

the

at temperatures

lowest

(35C)

temperature

germination

selection.

was

Germination

selection was

of

of

(15C)

and

greatest
of

25C,

seed

and

the

for

and
this

£3. alm u m .
both

selections

Germination

20C,

to

than

overwintering and non-overwintering Michigan
similar

significant

exception

non-overwintering

except

selections.

overwintering

The

generalization as with rhizome
almum

overwintering

there

germination

selections

seeds

S.

the

at

all

of

the

selections was

30C,

highest

however,

at

temperature

the

non-overwintering

from the

non-overwintering

60% and 77% at 15C and 35C compared with 32%

and 53% for the overwintering selections.
As with rhizome sprouting, it is of interest to compare
seed germination of the two Michigan selections with that of
the £3. halepense
and

S.

almum.

selections
Germination

from Mississippi
of

the

and Tennessee

overwintering

Michigan

selection and the S. halepense selection from Mississippi is
similar

at

all

temperatures

except

20C

whereas

the

non-overwintering selection exhibited greater germination at
all temperatures except 25C and 30C
of

both

the

overwintering

and

(Table 2).

Germination

non-overwintering

Michigan

81

selections

is

similar

to

the

Tennessee

selection

halepense at all temperatures except 2 5 °C and 3 5 °C.
due

to

the

selection

greater

germination

relative

to

the

rate

of

Mississippi

the

of

$.

This is
Tennessee

selection

which

results in fewer differences between this selection and the
non-overwintering

Michigan

selection.

Both

Michigan

selections exhibit significantly less seed germination than
the selection of
20C

almum at all temperatures above 20C.

S.

germination

percentage

is

>

selections whereas
Michigan

at

selection

*

similar

less

all

three

•

15C germination

is

for

At

than

of the

both

S.

overwintering

almum

and

the

non-overwintering Michigan selection.
The

results

germination
at

lower

rate

of
for

this
seeds

temperatures.

rhizomes

of

these

rhizomes

show

relative

to

demonstrate

a

of non-overwintering

Given

the

selections

decreased
the

study

poor

and

sprouting

overwintering

at

selections

survival

the

fact
lower

selections,

higher

rate

that

of

these

temperatures
it

would

be

advantageous for seeds of these non-overwintering selections
to germinate at lower temperatures than their overwintering
counterparts in order to establish plants and be competitive
early

in

selections

the
to

season.
germinate

The
at

ability
lower

of

seeds

temperatures

of
may

these
also

represent an adaptation to more northern climates as in most
cases

non-overwintering

selections

originate

in

more

82

northern locations than overwintering selections.
tion

of

seeds

of

the

overwintering Michigan

Germina­

selection

was

similar in most cases to that of the S. halepense selections
from Tennessee and Mississippi while seeds of both Michigan
selections was less than that of £3. alm u m .
this

data

as

in

the

non-overwintering

previous

Michigan

It appears from

experiments

selection

that

does

if

represent

the
a

selection of £3. almum, it as well as the other non-overwin­
tering selections in this study are distinct ecotypes.

Effect of Cold Temperature on Rhizome Viability

The

results

of

this

study

illustrate

the

extreme cold temperatures of rhizome viability.

effects

of

Exposure of

rhizomes to temperatures of -4C and -7C for 24 hours or more
was

sufficient

to

kill

rhizomes

of

all

four

selections,

whereas exposure of rhizomes to 5C for up to 4 days had no
effect

of

rhizome

viability

of

any

selection

(Table

3) .

Exposure to OC had little effect on viability of rhizomes of
the overwintering selections from Michigan and Tennessee but
significantly
Michigan

reduced

selection

viability

and

£3.

of

almum

the

non-overwintering

(Figure

1,

Table

3).

Percent sprouting following four day exposure to OC for the
overwintering

selections

77.8% and 72.2%,

from

Michigan

and

Tennessee

respectively,

compared

to 24.5%

and

was

44.5%

83

for the

non-overwintering Michigan

selection

and j3. a l m u m .

These results illustrate the increased susceptibility of the
non-overwintering
increased

selections

susceptibility

to

cold

would

temperatures.

naturally

This

reduce

the

potential of these selections to reproduce from rhizomes in
areas where soil temperatures are 0°C or below for extended
periods

of

time,

overwintering
winter

whereas

selections

temperatures

the
may

and

more
be

temperature

able

reproduce

to

from

tolerant

tolerate
both

these

seeds

and

rhizomes the following spring.

Overwintering Ability of Eight Sorghum Selections

Table
eight
the

4

sorghum

southern

differences

selections
Michigan
existed

overwintering
overwintering
survival

demonstrates

of

the

location

(Berrien County)

overwintering

exhibited

with

no

At

between

selections.

an

average

significant

of

distinct

abilities

non-overwintering

selections
47.0%

abilities

at two locations in Michigan.

in

and

overwintering

The
percent

differences

among

selections while the non-overwintering selections exhibited
a

survival

location

rate

(Montcalm

overwintering
selections

of

only
County)

ability

exhibiting

5.0%

there

among
poor

overall. At
was

any

survival.

no

the

differences

selections
It

northern

is

of

with

in
all

particular

84

interest to note the
the two Michigan
southern

results of this experiment

selections.

selection

relative

to

location

the

At the

showed

the

location

increased rhizome

northern

survival

southern

concerning

selection. At

rate was

poor

survival

the

for both

the

northern

the

northern

and southern selection.
Records of soil temperatures for the
at

depths

These

of

10

records

and

20

cm are

demonstrate
„

temperature

at the two

shown

the

winter of 1985/86

in Figures

2 and

differences

in

3.

soil

•• t ..

—

locations during the winter months.

At the southern location temperatures at the 20 cm depth did
not

fall below

OC

the

entire

winter while

temperatures

at

the 10 cm depth remained at OC to 1C throughout the winter.
Although in the previous experiment,
rhizomes

of

following

the

4-day

significant survival of

non-overwintering
exposure

to

OC,

selections

it

is

results of this experiment that these

was

apparent

shown

from

same rhizomes

the

cannot

tolerate exposure to this temperature for prolonged periods
of

time while

possess

this

locations were

the

rhizomes

ability.
less

of

Soil

than

0°C

overwintering

temperatures
for most

of

selections

at
the

the

do

northern

winter

with

lows of -5C at the 20 cm depth and as low as -10C at the 10
cm

depth.

As

temperatures,

seen

in

the

for

even

a

previous
short

experiment,
period

of

these
time,

low
are

85

sufficient to cause death of rhizomes of both overwintering
and non-overwintering selections.
It

is

apparent

from

the

results

of

this

and

the

preceding experiment that the degree of rhizome survival of
Johnsongrass

selections

temperature

and

that

is

very

greatly
little

influenced

overwintering

by

soil

of

these

rhizomes will occur in areas where winter soil temperatures
fall below

OC

overwintering

for extended
Michigan

selection
a

temperature

tolerance

periods

than

—

of

time.

Although

exhibited

some

the

greater

* *

the

£3. halepense

selection

from

Tennessee in the previous experiment, this adaptation, if it
exists,
of

has very little impact on the overwintering ability

this

selection

southern locations.

relative

to those

from

other,

more

More likely, rather than any adaptation

to lower temperatures it is the higher soil temperatures in
the southern part of Michigan which are allowing rhizomes of
this

selection

occurring
likely

at

that

to

more

overwinter.
northern

reproduction

is

If

latitudes
taking

this selection
in

place

is

Michigan,

it

via

rather

seed

is

than rhizomes whereas reproduction of the non-overwintering
selection is occurring exclusively by seed regardless of the
location infestations are occurring.

86

Effect of Cold Temperature on Fatty Acid Composition of Cell
Membrane Phospholipids

The

previous

cold tolerance
relative

to

objective

two

of the

that

of

the

differences

the

decreased

non-overwintering Michigan

selection

of

the

from

demonstrated

overwintering

following

existed

phospholipids

studies

study

in the

was

fatty

cell

membranes

may

account

selections

which

temperature

susceptibility.

selection of S. halepense

to

determine

acid
of

The
if

any

composition

rhizomes

for

For

selection.

this

from

of

these

differential

comparative

purposes,

a

from Tennessee and a selection of

£. almum from minnesota were also included.
Previous

studies

have

suggested

that

the

degree

of

saturation of the fatty acids in cell membranes play a role
in cold temperature

tolerance

in

that

those

plants with

a

higher percentage of unsaturated fatty acids are better able
to

withstand

individual
saturated

cold

fatty
(U:S)

phospholipids
exposure

to

temperatures
acid

ratio

for
OC or

for

the
5C

content
fatty

four
wherein

greater degree of unsaturation.
for

4 days

ratio

resulted

for the

in

a

(8).

Table

and

the

acids

selections
a higher

of

5

shows

the

unsaturated
cell

membrane

following
number

to

4

day

indicates

a

Exposure of rhizomes to OC

significant

overwintering Michigan

increase
selection

in
but

the U:S
had

no

87

effect on any of the other three selections.
resulted

in

a

significantly

overwintering

Michigan

higher

selection

non-overwintering selection.

in

the

selection.
accounts

membrane

Prior

for

48%

to
of

total

of

fatty

acids

the

overwintering
palmitic
while

acid

linoleic

These results suggest

selection

demonstrated in the previous experiments,

however,

in these

experiments

susceptibility to

difference
three

which

the

in

the

U:S

a greater

either

Tennessee
ratio
this

of

the

overwintering

selection

but

demonstrated
ratio

is

by

exhibited

similar

cold

Michigan

there
any

of

is

no

these

significantly greater

almum than the non-overwintering Michigan

therefore,
four

or

than

selections while

for S.

tolerance

S^. almum exhibited

temperatures

selection

cold

in part responsible
this

cold

greater

to

Following 4 day exposure to 0°C the

that the degree of unsaturation may be
the

the

treatment

percentages changed to 37% for each.

for

the

(16:0) and linoleic acids

temperature

acid accounts for 25%.

for

relative

phospholipids

the

ratio

This increase is due mainly to

a shift in the amounts of palmitic
(18:2)

U:S

This increase

tolerance.

It

is

selection
difficult,

to base the differential cold tolerance of these

selections

solely

upon

differences

in

the

degree

of

saturation of the fatty acids in the membrane phospholipids.
It is apparent from these studies that the rhizomes of
the non-overwintering selections are less vigorous and less

88

tolerant

to

selections,
ability

cold

temperatures

while

to

seeds

germinate

overwintering

at

of

than

these

lower

selections.

the

overwintering

selections

soil

This

possess

temperatures
would

an

than

indicate

the
that

Johnsongrass infestations in which rhizome reproduction is a
major

factor

temperatures
time.

If

would
do not

be

fall below

infestations

occur in areas where
for

long

limited

periods,

of

to

OC

these

areas

is

soil

for extended periods
overwintering

soil temperatures
it

where

likely

selections

fall below

that

of

freezing

reproduction

is

occurring by seed rather than rhizomes and control measures
could therefore be similar to those used for annual grasses
rather

than

those

used

Michigan,

Johnsongrass

counties

produce

to

control

perennial

infestations

abundant

in

rhizomes

the

species.
southern

which

due

In
most

to

the

relatively warm soil temperatures overwinter well but cannot
tolerate

the

locations,
produce

cooler

while

few

does

not

selections
individual

appear
by

seed

temperatures

infestations

rhizomes

soil temperatures.

soil

which

in

are

more

highly

in

more

northern

northern

counties

susceptible

Based on the results of this
that

the

is

limited

infestations

have

spread
by

of

either

climate

most

likely

but

to

low

study,
of

rather

resulted

it

these
that
from

separate introduction of one of these two selections into an
area.

89

In

the previous

study,

it was

seen

that

the

southern

selection was morphologically similar to S. halepense while
the northern selection appeared similar to S. a l m u m .
similarities,

particularly

between

the

northern

These

selection

and £3. alm u m , were not as apparent in rhizome sprouting and
seed

germination

similar.

It

although

appears

that

cold
if

temperature
the

northern

tolerance
selection

was
is

indeed S. almum it represents a distinctly different ecotype
than
while

the
the

one

used

for

overwintering

comparative

purposes

selection appears

in

quite

this

study

similar in

morphology, rhizome sprouting ability, seed germination, and
temperature tolerance to the selections of S^. halepense and
most likely represents an ecotype of this species.

90

Table 1 . Effect of temperature on rhizome sprouting of 10 sorghum
selections3.

15

T em p eratu re (°C)
25

30

S p ro u tin g

S e le c tio n

(%)
O v e rw in te rin g
M ichigan
O n ta rio
New York
Ohio
T ennessee
M is s is s ip p i

66bcde
66bcde
33fgh
75abcd
83abc_
58 cd ef

91ab
91ab
83abc
75abcd
91ab
9 la b

83abc
83abc
75abcd
75abcd
91 ab
100a

8h
50defg
25gh
75abcd

3 3 f gh
33fgh
4 1 efg
75abcd

83abc
83abc
83abc
75abcd

63a
39b

87a
45b

84a
81a

N on-O verw intering
M ichigan
Illin o is
O n ta rio
S . almum
Type Mean
O v e rw in te rin g
N o n -o v e rw in te rin g

^eans followed by the same letter are not significantly different at the
0.05% level as determined by Duncans Multiple Range Test.

91

Table 2. Effect of temperature
selections .

15

of

seed

germination

20

T em perature ( °C)
25

of

10

sorghum

30

35

G erm ination

S e le c tio n

(%)
O v e rw in te rin g
M ichigan
O n ta rio
New York
Ohio
T ennessee
M is s is s ip p i

32pq
18qr
31pq
8r
6 1 g -l
35op

52jklm
38nop
6 2 f-l
20qr
58h-m .
38nop

50klmn
43mnop
58h-m
30pq
73b-h
6 0 h -l

76b-g
6 0 h i jk l
7 2 c -i
481mno
80abcd
6 3 e -l

53jklm n
51jklm n
7 1 c -i
52jklm
78abcde
5 5 j-n

6 Oh-1
35op
43mnop
7 2 c -i

6 5 e-k
76b-g
52jklm n
6 3 e -l

481-0
481-0
53jklm n
82abc

7 8 a-e
6 6 d -j
631mno
87ab

7 7 b -f
57i-m
6 1 g -l
92a

31g
45f

45f
64cd

52ef
58ef

66cd
74cd

60de
72cd

N o n -o v e rw in te rin g
M ichigan
Illin o is
O n ta rio
S . almum
Type Mean
O v e rw in te rin g
N o n -o v e rw in te rin g

^eans followed by the same letter are not significantly different at the
0.05% level as determined by Duncans Multiple Range Test.

92

Table 3. Effect of cold temperature on rhizome survival of 4 sorghum
selections8.

S e le c tio n
M ichigan^
(OV)

M ichigan
(NOV)

£

T ennessee

T em perature

D u ra tio n

S p ro u tin g

(°C)

(d ay s)

(%)

S . almum

5

1
2
3
4

83abcd
89abc
94ab
94ab

91ab
74bcde
74bcde
100a

0

1
2
3
4

89abc
83abcd
88abc
77bcd

lOOab
74bcde
58def
24g

-4

1
2
3
4

Oh
Oh
Oh
Oh

Oh
Oh
Oh
Oh

Oh
Oh
Oh
Oh

Oh
Oh
Oh
Oh

-7

1
2
3
4

Oh
Oh
Oh
Oh

Oh
Oh
Oh
Oh

Oh
Oh
Oh
Oh

Oh
Oh
Oh
Oh

lOOab
94ab
94ab
94ab
72bcde
88abc
72bcde
72bcde

89abc
lOOab
89abc
lOOab
lOOab
61cdef
38fg
44fg

^ e a n s fo llo w e d by th e same l e t t e r a r e n o t s i g n i f i c a n t l y d i f f e r e n t a t th e
0.05% l e v e l a s d e te rm in e d by Duncans M u ltip le Range T e s t.
^OV *= O v e rw in te rin g .
c

NOV = N o n -o v e rw in te rin g .

93

in

Duration

-K>

(DAYS)

co

O

W

O

O

00

O
CO

o

^

2

O

• 0) s

•-

t- 2

2

o

O

CM

(%) pAi/uns
Figure 1.

Percent rhizome survival following exposure to OC
for 1, 2 , 3 , or 4 days.

94

T ab le 4 .

O v e rw in te rin g a b i l i t y o f 8 sorghum s e l e c t i o n s a t 2 l o c a t io n s in
M ichigan3 .

Location**
S o u th e rn

N o rth e rn
S e le c tio n

S u r v iv a l
(%)

O v e rw in te rin g
M ichigan
O n ta rio
Ohio
T ennessee
M is s is s ip p i

2 0 .Obc
5 .0 c
0 .0 c
1 0 .0 c
0 .0 c

5 0 .0 a
4 0 .Oab
4 0 .0 ab
5 5 .0 a
5 0 .0 a

N on-O verw intering
M ichigan
O n ta rio
S . almum

0 .0 c
0 .0 c
0 .0 c

0 .0 c
1 0 .0 c
5 .0 c

7 .0 b
0 .0 b

4 7 .0 a
5 .0 b

Type Mean
O v e rw in te rin g
N o n -o v e rw in te rin g

^ e a n s fo llo w e d by th e same l e t t e r a r e n o t s i g n i f i c a n t l y d i f f e r e n t a t th e
0.05% l e v e l as d e term in e d by Duncans M u ltip le Range T e s t.
^N o rth e rn = Montcalm C ounty, M ich ig an .
M ichigan.

S o u th ern = B e r rie n C ounty,

95

o

£

CM
o
CM

CD

O
CM

Z

<

CM O
bJ
Q

T

T

CM

T

§

o
CM Z

T

CM
I

I

CO
I

CO
I

O

T

(q ) ©jn}DJ3duiai

Figure 2.

Soil Temperature —

Southern Location.

DATE

LU
U.

96

O

CM

O
m
LU
Li_

DATE

CM

z
<
“5

CM o
Ld
O

CM

O

CM
I

CO

CO

o

O
CM

(q ) 3jn}DJ9dLU91

Figure 3.

Soil Temperature —

Northern Location.

97

Table 5. Effect of cold temperature on fatty acid composition of rhizome
phospholipids in 4 sorghum selections .

F a tty Acid C om position
B iotype

1 6 :0

1 8 :0

1 8 :1

1 8 :2

1 8 :3

U:S R a tio b

No T reatm en t
M ichigan (OV)C.
M ichigan (NOV)
T ennessee
S. almum

49ab
52a
38cd
42bcd

6 .3 a
7 .8 a
9 .8 a
6 .7 a

15 ab
15a
13abc
12abc

25bc
19c
36a
35a

4 .4 b
4 .0 b
6 .3 b
5 .0 b

0.80bcd
0 . 65d
1 .1 8 a
1 .0 8 ab c

4 .4 b
4 .1 b
6 .3 b
3 .6 b

0 . 91abcd
0.85bcd
1 .06abcd
0 . 74cd

5°C
M ichigan (0V)
M ichigan (NOV)
T ennessee
S . almum

47abc
45abcd
42bcd
52a

5 .7 a
9 .6 a
6 .2 a
4 .8 a

llb c
16a
lOcd
lOcd

32ab
25bc
35a
27abc
0°C

M ichigan (0V)
M ichigan (NOV)
T ennessee
S. almum

38d
49ab
42bcd
39cd

8 .4 a
9 .4 a
6 .1 a
7 .6 a

12abc
15a
7d
lOcd

38a
21bc
29abc
38a

3 .8 b
3 .0 b
1 6 .1 a
5 .7 b

1 .2 0 a
0 . 69d
l.lO a b c
1 . 14ab

^ e a n s w ith in a column fo llo w e d by th e same l e t t e r a r e n o t s i g n i f i c a n t l y
d i f f e r e n t a t th e 0.05% l e v e l a s d e te rm in e d by Duncans M u ltip le Range
T e s t.
bU:S = U n s a tu r a te d :s a tu r a te d f a t t y a c id r a t i o .
c
0V = O v e rw in te rin g .
^NOV = N o n -o v e rw in te rin g .

LITERATURE CITED

1.

Burt, G.W.
1974.
Sci. 22:59-63.

2.

Burt, G.W. and I.M. Wedderspoon.
1971.
Growth of
Johnsongrass selections under different temperatures
and dark periods.
Weeds Sci. 19:419-423.

3.

Chernicky, J.P. and F.W. Slife.
1985.
strain of Illinois sorghum to Tennessee
Weed Sci. 33:328-332.

4.

Folch, J., M. Lees, and G.H. Sloane-Stanley.
1957.
A
simple for the isolation and purification of total
lipids from animal tissues.
J. Biol. Chem. 226:497509.

5.

Horowitz, M.
1972.
Early development of Johnsongrass.
Weed Sci. 20:271-273.

6.

Hull, R.J.
1970.
Germination control of Johnsongrass
rhizome buds.
Weed Sci. 18:118-121.

7.

Ingle, M. and B.J. Rogers.
1961.
The growth of a
midwestern strain of Sorghum halepense under controlled
conditions.
Am. J. Bot. 48:392-396.

8.

Lyons, J.M.
1973.
Rev. Plant Physiol.

9.

McWhorter, C.G.
Johnsongrass
in
19:496-500.

10.

Adaptation

of

Johnsongrass.

Chilling injury
24:445-466.

1971.
the

in

Weed

Comparing a
Johnsongrass.

plants.

Ann.

Introduction and spread of
United
States.
Weed
Sci.

McWhorter, C.G.
1972.
Factors affecting Johnsongrass
rhizome
production
and
germination.
Weed
Sci.
20:41-45.

98

99

11.

Metcalfe, L.D., A.A. Schmitz, and J.R. Pelka.
1966.
Rapid preparation of fatty acid esters from lipids for
gas chromatographic analysis.
Analyt. Chem. 38:514515.

12.

Rivera, C.M. and D. Penner.
1978.
Rapid changes in
soybean root membrane lipids with altered temperature.
Phytochem. 17:1269-1272.

13.

Scwertner,
H.A.
and
J.B.
Blale.
1973.
Lipid
composition of plant mitocondria and chloroplasts. J.
Lipid Res. 14:235-242.

14.

Stoller, E.W.
1977.
Differential cold
quackgrass
and
Johnsongrass
rhizomes.
25:348-351.

15.

Taylorson,
R.B.
and
C.G.
McWhorter.
1969.
Seed
dormancy and germination in ecotypes of Johnsongrass.
Weed Sci. 17:359-361.

16.

Warwick, S. I. and L.D. Black.
1983.
The biology of
Canadian weeds.
61.
Sorghum halepense (L.) Pers; Can.
J. Plant Sci. 63:997-1014.

17.

Wedderspoon, I.M. and
development of three
Sci. 22:319-322.

G.W. Burt.
Johnsongrass

tolerance of
Weed
Sci.

1974.
Growth and
selections.
Weed

CHAPTER FOUR

CONTROL OF TWO V7EEDY SORGHUM SELECTIONS IN MICHIGAN
WITH SELECTIVE AND NON-SELECTIVE HERBICIDES

ABSTRACT

Johnsongrass
re la tiv e ly
very

new weed

little

measures

attempt

problems
halepense
almum

has

of

the

been made

and

sorghum
an

it

state
to

are

Pers.]

of

is

Michigan

determine

equally

species

overwintering

a non-overwintering

(Parodi)

(L.)

if

a
and

control

effective

in

previous experiments have suggested

two

in Michigan,
and

in

elsewhere

In addition,

existence

halepense

problem

effective

Michigan.
the

[Sorghum

was

type

unknown

if

present
type

as

similar

similar
these

respond similarly to these herbicide treatments.

weed
to _S.

to

Sorghum

two

species

Test plots

were established at two locations in Michigan in the spring
of 1984 and 1985 to evaluate the efficacy of four selective
postemergence herbicides for control of these two selections
in

soybeans

the northern

[Glycine
location

max

(L.)

Merr.].

The

infestation

(Eaton County, Michigan)

100

at

consisted of

101

the

non-overwintering

southern
the

location

overwintering

type

while

(Berrien
type.

the

infestation

County,

Michigan)

Herbicides

applied

at

the

consisted
was

of

fluazifop

{ (-+-) —2— [4— [ (5-(trifluoromethyl)-2-pyridinyl) oxy] phenoxy] pro­
panoic acid}, haloxyfop

(2-[4-[[3-chloro-5-(triflouromethyl)

-2-pyridinyl]oxy]phenoxy]

propanoic acid), guizalofop

(6-chloro-2-guinoxalinyl)oxy]phenoxyl]propionic

(2 — [4 —

acid),

and

sethoxydim {2-[1-(ethoxyimino)butyl]- 5 - [ 2 - (ethylthio)propyl]
-3-hydroxy-2-cyclohexen-l-one}
kg/ha

in

1984

and

0.06,

at

rates

0.12,

and

of

0.25

0.12

and

kg/ha

in

0.25
1985.

Treatments were applied early postemergence when plants were
30 cm high or late postemergence when plants were 45 cm high
or

as

early

a

split

application

postemergence

postemergence.
late

and

with

one

one

half

half
the

the

rate

rate

applied

applied

late

Control was greatest for treatments applied

postemergence

or

as

a

split

application.

Treatments

applied as a single early postemergence application provided
greater

control

of

the

northern

than

the

southern

type.

Control of regrowth in the year following treatment was also
greater at the northern than southern location.

Plots were

also established to evaluate three non-selective herbicides
for

control

established
location
location

in
in

of
at

these
two

locations

Montcalm
Berrien

same

County,

County,

selections.
in

Michigan,

Michigan

Michigan.

and

Plots

were

a

northern

a

southern

Herbicides

applied

102

were

glyphosate

(N-(phosphonomethyl)

(trimethylsulphonium
and

HOE-661

phosphinate)

at

glycine),

carboxymethylaminomethyl

sulphosate

phosphonate),

(ammonium-(3-amino-3-carboxypropyl)-methyl
rates

volume of 140 or 280

of

0.84

and

1.68 kg/ha

1/ha when plants were

height or at the boot to head stage.

in a carrier

45 to

60 cm in

Treatments applied at

the boot to head stage provided greater control than those
applied

earlier.

Where

differences

existed,

treatments

applied in the lower carrier volume provided greater control
e

than

those

little

applied

in

difference was

—

the

* *

higher

observed

or between the two locations.

among

carrier

volume.

individual

Very

herbicides

INTRODUCTION

Johnsongrass
control

is

a

highly

in infested areas

production,

however,

production

make

non-selective

is essential

its

effective

herbicides

competitive

prolific
control

such

species

its

for successful

crop

rhizome

seed

difficult.

as

and

and
The

glyphosate

use

has

of

proven

effective in non-crop areas or as an application to emerged
Johnsongrass
introduced
excellent
among

to

planting

postemergence
Johnsongrass

these

haloxyfop.
mays

prior

are

(1, 5, 10) .

grass

herbicides

control

fluazifop,

in

soybeans

sethoxydim,

applications
(S-ethyl

of

dipropyl

thiocarbamate

bis(2-methylpropyl)carbamothioate)
controlling
provide

seedling

consistent

from

rhizomes

long

lasting

(7, 11) .
control

or

long

(2, 4, 6, 8),
and

in corn

such

butylate

however,

control

Currently

measures

provided

[Zea

as

EPTC

(S-ethyl

have proven effective

Johnsongrass,

season

have

Preplant incorporated

herbicides

carbamothioate)

recently

quizalofop,

Selective control of Johnsongrass

(L.)] has proven more difficult.

The

for

the

of

they

plants

most

do

not

emerging

effective

Johnsongrass

in

in

and

field

crops consist of combinations of tillage, crop rotation, and

103

104

the use of selective postemergence and preplant applications
or selective placement of non-selective herbicides.
The

results

of

recent

studies

have

indicated

the

existence of overwintering and non-overwintering ecotypes of
Johnsongrass
Ontario,
have

in

Michigan,

Canada

(3, 12) .

wider

leaf

significantly

less

Ohio,

New

The

York,

Illinois,

non-overwintering

ecotypes

blades,

thicker

culms,

rhizomes

than

overwintering

the

and

and

produce
types.

These studies have suggested the non-overwintering ecotypes
^

more

closely

halepense.

resemble
Due

to

the

the

'

less

reduced

•

perennial
rhizome

£3. almum than

production

and

S.
the

lower capacity of these rhizomes to survive the winter it is
possible that control practices
ecotypes

may

differ

control

the

more

addition,

studies

variation

in

herbicide

dalapon

possible

that

for these non-overwintering

dramatically
vigorous

by

of

those

overwintering

McWhorter

response

from

(9)

have

Johnsongrass

(2,2-dichloropropionic

these

overwintering

and

required

ecotypes.

indicated
ecotypes
acid).

to
In

a

wide

to

the

It

is

non-overwintering

Johnsongrass ecotypes may demonstrate differential responses
to herbicide treatments as well.
The objectives of the current study were to investigate
the

response

ecotype

of

of

an

overwintering

Johnsongrass

in

and

Michigan

to

non-overwintering
applications

of

several selective and non-selective herbicides in the field.

-

MATERIALS AND METHODS

Johnsongrass Control in Soybeans

and

Field

experiments

1985

to

were

investigate

non-overwintering

established
control

populations

of

in

of

spring

of

1984

overwintering

and

Johnsongrass

in

with several selective postemergence herbicides.
established

in

population)

and

population).

Eaton

County,

Berrien

County,

Herbicides

fluazifop,

haloxyfop,

0.25 kg/ha

in

1984

Michigan

sethoxydim

0.06,

0.12,

(overwintering

were

at
and

Plots were

(non-overwintering

investigated

and

and

Michigan

Michigan

quizalofop,

rates

of

0.25 kg/ha

0.12

and

in 1985

applied as a single application when Johnsongrass was 30 cm
in height

(early postemergence),

postemergence) , or as
applied

early

postemergence.
concentrate.

a

split

postemergence
All

45

cm in height

application with

and

treatments

or

H

the

included

rate
2.34

(late

the

rate

applied

late

h

L/ha

crop oil

Treatments were applied with a tractor mounted

sprayer in a spray volume of 280 L/ha at a pressure of 345
kPa using Tee-Jet 730308 flat fan nozzles.

Soil texture was

a clay loam at Eaton County with 4.0% organic matter and a

105

106

pH of 6.0 and a sandy clay loam with 3.0% organic matter and
a pH of 7.2 at Berrien County.
cm rows at each location.
at

Eaton

Planting

County
date

and

in

Soybeans were planted in 76

Soybean varieties were Corsoy 79

Pioneer

1984

was

June

2480

at

6

both

at

Berrien

County.

locations.

In

1985, planting date was May 25 in Berrien County and May 28
in Eaton County.

Plot evaluations were made 14 and 28 days

after treatment at each location in 1984 and 14,
days

after

treatment

at

each

location

in

28, and 42

1985.

Percent

control was evaluated relative to an untreated control plot.
Ratings

were

treatment
control.

also

at

each

Plot

experimental

size

design

taken

in

July

location
was
was

3.0
a

to

of

the

year

evaluate

meters

by

randomized

following

residual

weed

meters.

The

12.2

complete

block

with

three replications.

Johnsongrass Control with Non-Selective Herbicides

Field plots were established in spring of 1984 and 1985
to investigate control of overwintering and non-overwinter­
ing

populations

of

non-selective

Johnsongrass

postemergence

established in Montcalm County,
population)
population).

and

Berrien

Herbicides

in

Michigan

herbicides.
Michigan

County,

Plots

several
were

(non-overwintering

Michigan

investigated

with

were

(overwintering
glyphosate,

107

sulphosate,

and HOE-661 applied at 0.84 and 1.68 kg/ha in a

carrier volume of 140 and 280 L/ha when Johnsongrass was 45
to 60 cm in height or in the boot to head stage.

Treatments

were applied with a tractor mounted sprayer at a pressure of
345

kPa.

matter

and

Soil texture was
a pH

of

6.0

a loamy

at

sand with

1.5%

the Montcalm County

organic

site

and

a

sandy clay loam with 3.0% organic matter and a pH of 7.2 at
the Berrien County site.

Plot evaluations were made 21 and

42 days after treatment.

Ratings were also taken in July of

the

year

control.

following

treatment

Plot

size

was

3.0

design

was

a

experimental
replications.

to

evaluate

meters

by

split-split

residual

weed

meters.

The

9.14
plot

with

three

RESULTS AND DISCUSSION

Johnsongrass Control with Selective Postemerqence
Herbicides

The

results

of postemergence
3

Johnsongrass
days

after

control

in

treatment,

—

herbicide

treatments

for

•

1984

are

control

shown

was

in Table

1.

approximately

At

90%

14

with

nearly all treatments except sethoxydim at 0.12 kg/ha which
exhibited
Control

only

of

65%

the

control

northern

after

treatment,

early

postemergence

Control

selection.

similar

at

applied

provided

as

reduced

28
a

all

selections was

days

single

control

Results in 1985 were similar

two

after treatment with

northern

was

treatments

treatment

of the

the

selection

however,

the southern selection.
2) .

of

of

(Table

similar at 14 days

treatments providing

good control

with the exception of sethoxydim which provided poor control
at the 0.12 kg/ha rate and only fair control at the higher
rate.
control

At

28

of

treatments

and
the

were

application.

42

days

southern
applied

as

after

treatment,

selection
a

single,

With the exception

108

was
early

as

in

1984,

reduced

when

postemergence

of sethoxydim,

there were

109

few differences among individual herbicides or rates.

Rates

of fluazifop butyl, quizalofop, and haloxyfop as low as 0.06
kg/ha provided control of the northern selection regardless
of

the

time

of

application

and of

the

southern

selection

when applied as a late postemergence treatment.
Since
particular

Johnsongrass

is

interest

evaluate

herbicide treatment

to

reduces

a

perennial
the

regrowth

plant

degree

it
to

in the year

is

of

which

a

following

application.

Treatments applied as split applications or as

single

late

postemergence

control

of Johnsongrass

(Table

3) .

Treatments

application

in

regrowth at both
applied

as

a

1984

provided

locations

single

in 1985

early

post­

emergence application provided poor control of regrowth when
applied at 0.12 kg/ha at the northern
rates

at

the

southern

location

location and at both

with

significantly

less

control of the southern than the northern selection in most
cases.

Treatments applied in 1985 provided regrowth control

of the northern selection in 1986 at all rates and treatment
times.

Control

of

regrowth

of

the

southern

selection

was

also provided by treatments applied as a split application
or

as

a

single

treatments
provided
nearly

late

applied

as

single

significantly
all

cases,

postemergence

less

control

treatment,

however,

early postemergence

treatment

control
of

in

many

regrowth

in

cases.

In

1986

was

110

significantly

better

for

the

northern

than

southern

selection.
The results
of

two

distinct

exception of
the

Regrowth
treatment

study provide

sorghum

selections

sethoxydim all

northern

treatments

vs.

of this

selection,

failed

of

the

was

to

also

significantly

from a differential

herbicides,

it

is

more

provided
early

the

selection

the northern selection.

arise

treatments

control

evidence

in Michigan.

however,

southern

additional

the

greater

the

control of

postemergence

southern
in

With

selection.

year

for

following

the

southern

Although this difference could
physiological

likely

that

tolerance

the

to these

extensive

rhizome

system produced by the southern selection causes control to
be more difficult than the northern selection which produces
few

rhizomes

as

is

the

case

with

these

herbicides

when

attempting to control an annual grass such as giant foxtail
(Setaria

faberi Herrm.)

[Agropyron repens

(L.)

vs.

a perennial

Beauv.].

such as quackgrass

It is therefore

important

for growers to determine which of these two selections are
present prior

to

choosing

a control

strategy

applications appears to be more critical

as

for the

rhizomatous selection than the northern selection.

timing

of

southern,

Ill

Johnsongrass Control with Non-Selective Herbicides

Tables
carrier

4 and

volume

non-selective
treatment
rating

show

the

1984

date

there

and

1985,

of

control

as

were

and values

and carrier volume,

effects

Johnsongrass

herbicides

in

treatments

on

5

growth
provided

evaluated

21

respectively.

essentially

no

stage
by

three

days
At

after

this

early

differences

among

shown are averaged over growth

respectively.

90% or greater control which

and

stage

All treatments providing

indicates

that all

treatments

performed equally well in providing initial control of above
ground vegetation.
made

42

days

Tables

after

6 and 7 show results of ratings

treatment

in

1984

and

1985.

As

significant interactions existed, individual treatment means
are presented.
significant

Both growth stage and carrier volume had a

effect

on

control

in

1984.

In

treatments applied at the lower carrier volume
to

head

stage

provided

the

greatest

general,

at the boot

control.

Treatments

applied at the earlier stage provided good initial control,
however,
and

seeds

continue

reinfestation

reinfestation

also

to

germinate

occurs.
occurs

At
from

well

the

into

the

southern

previously

season

location

dormant

rhizome

buds which were not killed by these herbicide treatments at
the

early

herbicides

application
at

the

boot

time.
to

Application

head

stage

of

results

these
in

same

greater

112

translocation to and control of these rhizomes.

Control was

poor when treatments were applied at the early growth stage
in the higher carrier volume.
resulted

in

an

increase

in

the southern location.

Decreasing the carrier volume
control

with

all

treatments

at

Decreasing carrier volume increased

control provided by the high rates of all herbicides at the
northern location but control provided by the herbicides at
the lower rates was not effected.
differences

in

control

between
i

There were few consistent

the

*

two

locations with

the

*

exception that treatments applied at the boot to head stage
in the higher carrier volume provided significantly greater
control of the northern selection.
Control

in

1985

was

generally

differences among treatments.
in

1985

and

the

difference

greater,

with

fewer

Plants grew much more rapidly
in

time

late application time was short.

between

the

early

and

In addition, plant growth

was more variable with many plants entering the early boot
stage at the early application time.

This resulted in fewer

differences in control between the two application times and
in

some

cases

resulted

in

greater

applied at the early growth stage.
no differences

control

for

treatments

There were essentially

in control between the two growth

stages

or

between the two locations in 1985.
Tables 8 and 9 show control of Johnsongrass regrowth in
1985

and

1986,

one

year

following

treatment.

Control

was

113

80%

or

greater

HOE-661

which

treatments
boot

to

when

head

volume.

in

both

years

provided

less

applied

stage

There

to

at

were

for

the

the
few

all

treatments

control

than

northern

selection

lower

rate

and

other

consistent

except

all

other
in

higher

the

carrier

differences.

Although some treatments provided excellent control in 1984,
overall control was only fair.
year

following

treatments.
control,
rhizome
plants

treatment,

growth

production
from

however,

Many treatments,

inhibited

was

reaching

Control of regrowth

seed production begin.

good

with

most

while not providing excellent

to

such

reduced

a

was

in the

stage

or
of

an

extent

prevented
growth

that
by

where

seed

and

preventing
rhizome

and

It is possible that the depletion of

seed and rhizome reserves in the soil, without replenishment
during the growing

season may result

in greater

control

in

the year following treatment than was evident in the year of
treatment.

In 1985,

control was

good with most

and as a result control of regrowth the

treatments

following year was

excellent as well.
These
support
exist

the
as

results,

suggestion
weed
time

response

a change

Control

was

also

that

problems

application
to

particularly

the

those

two

of

distinct

1984,

tend

sorghum

in

Michigan.

At

the

southern

selection

showed

a

in

carrier

greater

at

volume

the

than

northern

the

to

species
early
greater

northern.

location

when

114

treatments

were

applied

higher carrier volume.
control

of

treatments.
between

the

the

selection

results

stage

boot

to head

stage

This was due primarily

southern

These

growth

at

and

suggest

carrier

obtained
that

volume

the

in

the

to the poor
with

these

interaction

is more

important

with the southern than the northern selection and, as stated
previously,

it

is

important

for

growers

with

these

weed

problems to recognize these differences when planning their
control programs.

115

T ab le 1 .

Jo h n so n g ra ss c o n tr o l i n soybeans 1984 a t 2 l o c a t io n s in M ichigan
w ith s e l e c t i v e p ostem erg en ce h e r b ic id e s .
L o c a tio n ^
N orth

South

N orth

28 DAT

14 DATC
H e rb ic id e

R ate

South

C o n tro l

(k g /h a )

(%)

E a rly P ostem ergence
F lu a z ifo p
Sethoxydim
H aloxyfop
Q u iz a lifo p

0 .1 2
0 .2 5
0 .1 2
0 .2 5
0 .1 2
0 .2 5
0 .1 2
0 .2 5

. -

97ab
100a
65d
• 97ab
98a
98a
93 a-c
98a

87bc
83c
93a-c
83c
93a-c
93a-c
9 0 a-c
93a-c

9 2 b -f
9 3 a-e
531
8 5 f-h
88d-g
9 3 a-e
9 0 c -f
88d-g

60k
67j
58kl
81h
9 0 d -f
73i
75 i
81h

97ab
87bc
9 0 a-c
97ab

97a-c
88e-g
9 7 a-c
9 3 a-e

9 0 c -f
87e-h
9 0 c -f
97a-c

E a rly P ostem ergence + L a te P ostem ergence
F lu a z ifo p
Sethoxydim
H aloxyfop
Q u iz a lifo p

0 .1 2
0 .1 2
0 .1 2
0 .1 2

+
+
+
+

0 .1 2
0 .1 2
0 .1 2
0 .1 2

97ab
87bc
97ab
9 3 a-c

L a te P ostem ergence
F lu a z ifo p
Sethoxydim
H aloxyfop
Q u iz a lifo p

0 .1 2
0 .2 5
0 .1 2
0 .2 5
0 .1 2
0 .2 5
0 .1 2
0 .2 5

Check

100a
100a
100a
100a
100a
100a
100a
100a
0m

98a
100a
93a-c
100a
97ab
95ab
100a
98a
0m

100a
100a
100a
100a
100a
100a
100a
100a
0m

C lean s w ith in a r a t i n g d a te fo llo w e d by th e same l e t t e r a re n o t
s i g n i f i c a n t l y d i f f e r e n t a t th e 0.05% l e v e l a s d e te rm in e d by Duncans
M u ltip le Range T e s t.
^N orth = E aton C ounty, M ichig an .
°DAT = Days a f t e r tr e a tm e n t.

South = B e r rie n C ounty, M ichigan.

98ab
100a
93a-c
100a
97a-c
95a-d
100a
98ab
0m

T able 2 .

Jo h n so n g rass
h e r b ic id e s 3 .

c o n tr o l in

soybeans in 1985 a t

2 lo c a tio n s

in M ichigan w ith s e l e c t i v e postem ergence

L o c a tio n
N orth

South

N orth

South

14 DAT0
Treatm ent

N orth

42 DAT

28 DAT

R ate

C o n tro l

(k g /h a )

(%)

South

E a rly Postem ergence
F lu a z ifo p

Q u iz a lifo p
Sethoxydim

100a
97a-c
100a
88a-h
97a-c
100a
95a-d
100a
100a
63i
78g

86a-g
91a-g
93a-e
87a-g
90a-g
89a-g
86a-g
90a-g
91a-g
63i
79 f-g

9 2 a -f
9 2 a -f
100a .
90a-g i
95a-d
100a
95a-d 1
100a
95a-d
57mn
7 5 f-l

92a-g
94a-d
95a-d
96a-c
91a-g
95a-d
62i
85b-g
95a-d

100a
100a
100a
100a
100a
100a
8 5 a -i
88a-g
93a-e

67j-m
7 7 d -l
8 3 a -j
63k-m
7 5 e -l
8 3 a -j
7 4 f-l
7 7 d -l
7 9 b -l
47n
67j-m

92a-d
92a-d
100a
90a-e
• 95ab
100a
95ab
100a
95ab
57k-m
75d-j

6 7 i-l
7 5 c-j
8 3 a -i
6 7 i-l
73d-k
7 5 c-j
6 8 i- l
7 0 g -l
73b-k
43mn
6 8 i-l

100a
94a-d
94a-d
98ab
94a-d
90a-g
66j-m
7 9 c -l
9 2 a -f

100a
100a
100a
100a
100a
100a
8 5 a -i
8 8 a -f
93a-c

100a
100a
100a
100a
100a
100a
6 7 i-l
87a-g
93a-c

E a rly Postem ergence + L a te Postem ergence
F lu a z ifo p
Haloxyfop
Q u iz a lifo p
Sethoxydim

0.06
0.12
0.06
0.12
0.06
0.12
0.06
0.12
0.12

+
+
+
+
+
+
+
+
+

0.06
0.12
0.06
0 .1 2
0.06
0.12
0.06
0.12
0.12

100a
100a
97a-c
100a
100a
100a
87a-g
93a-e
92a-g

116

H aloxyfop

0.06
0.12
0.25
0 .0 6
0 .1 2
0 .2 5
0 .0 6
0.12
0.25
0 .1 2
0 .2 5

Table 2 (Continued).

Location*5
N orth

South

N orth

South

14 DATC
T reatm ent

N orth

42 DAT

28 DAT

R ate

C o n tro l

(k g /h a )

(%)

South

L ate Postem ergence
F lu a z ifo p
Haloxyfop

Sethoxydim

93a-e
100a
100a
100a
100a
100a
92a-g
97a-c
100a
85b-g
95a-d
82d-g

100a
100a
100a
98ab
96a-c
98ab
97a-c
98ab
100a
47j
83c-g
100a

93a-e
100a
100a
9 2 a -f
95a-d
93a-e
95a-d
95a-d '
100a
80b-k
90a-g
73g-m

98ab
100a
98ab
94a-d
96a-c
100a
97a-c
94a-d
100a
70i-m
621-n
8 7 a -i

93a-c
100a
100a
92a-d
95ab
93a-c
95ab
95ab
100a
8 0 b -j
90a-e
73e-k

95ab
98ab
100a
90a-e
95ab
100a
100a
98ab
98ab
37n
531m
6 8 i-l

^ e a n s w ith in a r a t i n g d a te follow ed by th e same l e t t e r a r e n o t s i g n i f i c a n t l y d i f f e r e n t a t th e 0.05% l e v e l as
determ ined by Duncans M u ltip le Range T e s t.
^N orth = Eaton C ounty, M ichigan.
^A T = Days a f t e r tr e a tm e n t.

South = B e rrie n C ounty, M ichigan.

117

Q u iz a lifo p

0.0 6
0.12
0.25
0.06
0.1 2
0.25
0.0 6
0.1 2
0.25
0.0 6
0 .1 2
0.25

118

Table 3. Control of Johnsongrass regrowth in soybeans at two locations in
Michigan one year after treatment with selective postemergence
herbicides3 .
Y ear R ated
1986

1985
N o rth
R ate
(k g /h a )
E a rly P ostem ergence
0 .0 6
F lu a z ifo p
0 .1 2
0 .2 5
H aloxyfop
0 .0 6
0 .1 2
0 .2 5
Q u iz a lifo p
0 .0 6
0 .1 2
0 .2 5
0 .1 2
Sethoxydim
0 .2 5

L o c a tio n ^
South
N o rth

H e rb ic id e

C o n tro l
(%)
67ghi
80def

6 3 h ij
6 0 ijk

75ef g
86cd

5 6 jk
6 0 ijk

80def
80def
52k
6 0 ijk

6 0 ijk
73f gh
6 0 ijk
73f gh

E a rly P ostem ergence + L a te P o stem erg en ce
F lu a z ifo p
0 .0 6 + 0 .0 6
88bcd
0 .1 2 + 0 .1 2
H aloxyfop
0 .0 6 + 0 .0 6
0 .1 2 + 0 .1 2
85cde
Q u iz a lifo p
0 .0 6 + 0 .0 6
0 .1 2 + 0 .1 2
94abc
0 .0 6 + 0 .0 6
Sethoxydim
0 .1 2 + 0 .1 2
82def
L a te P ostem ergence
F lu a z ifo p
0 .0 6
0 .1 2
0 .2 5
H aloxyfop
0 .0 6
0 .1 2
0 .2 5
Q u iz a lifo p
0 .0 6
0 .1 2
0 .2 5
Sethoxydim
0 .0 6
0 .1 2
0 .2 5

South

85cde
87bcd
88bcd
82def

93abc
97ab

50k
68ghi

97ab
99a

80def
73f gh

90a-d
94abc

73f gh
67 g h i

67ghi
86cd

75efg
5 3 ik

100a
98a
100a
100a
97ab
9 5 a-c
93a-d
100a
100a
93a-d
100a

85c-g
84d-g
86c-g
7 7 g -i
8 0 f-h
87b-g
8 3 ef g
83d-g
82efg
7 0 i-k
8 1 f-h

98a
100a
9 0 a -f
98a
100a
100a
100a
97ab

93a-d
95a-c
9 0 a -f
9 0 a -f
9 2 a-e
85c-g
8 7 b -f
95abc

98a
97ab
100a
100a
93a-d
97ab
97ab
100a
98a
100a
100a
98a

87b-g
85c-g
80f gh
7 0 ijk
80fgh
85c-g
95abc
85c-g
85c-g
65 j k
62k
65_ik

aMeans w ith in a r a t i n g d a te fo llo w e d by th e same l e t t e r a r e n o t
s i g n i f i c a n t l y d i f f e r e n t a t th e 0.05% l e v e l a s d e te rm in e d by Duncans
M u ltip le Range T e s t.
^N orth = E aton C ounty, M ich ig an .

South = B e r r ie n C ounty, M ich ig an .

Table 4. Effects of carrier volume and stage of growth at time of application on Johnsongrass control 21 days
after treatment with non-selective herbicides in 1984 .

Selection**
S o u th ern

N o rth ern

>

N o rth e rn

S tag e o f Growth
H e rb ic id e

R ate

45-60

(k g /h a)

(cm)

Boot to Head

45-60

Southern

C a r r ie r Volume
Boot to Head

140

(cm)

280

140

280

(L /ha)

Jo h n so n g ra ss C o n tro l

G lyphosate
S u lp h o sate
HOE-661

0 .8 4
1.68
0.84
1.68
0.84
1 .6 8

100a
100a
100a
100a
93bc
100a

95abc
97ab
98ab
100a
91c
96ab

97ab
93bc
95abc
93bc
97ab
97ab

119

(%)
97ab
99a
99a
100a
95abc
95abc

95ab
100a
99ab
100a
89c
97ab

100a
97ab
99ab
100a
95ab
99ab

99ab
96ab
97ab
98ab
94b
96ab

95ab
97ab
97ab
95ab
97ab
96ab

^ e a n s w ith in c a r r i e r volume and growth s ta g e fo llo w ed by th e same l e t t e r a re n o t s i g n i f i c a n t l y d i f f e r e n t a t th e
0.05% l e v e l a s d eterm in ed by Duncans M u ltip le Range T e s t.
^N orthern = Montcalm C ounty, M ichigan.
\

S o u th ern = B e rrie n C ounty, M ichigan.

Table 5. Effects of carrier volume and stage of growth at time of application on Johnsongrass control 21 days
after treatment with non-selective herbicides in 1985 .

S e le c tio n ^
N o rth ern

S o u th ern
S tag e o f Growth

H e rb ic id e

R ate

45-60

(k g /h a)

(cm)

Boot to Head

45-60

S outhern

N o rth ern
C a r r ie r Volume

Boot to Head

140

(cm)

280

140

280

(L /ha)

Jo h n so n g rass C o n tro l
(%)
G lyphosate
S u lp h o sa te
HOE-661

0.84
1.68
0.84
1 .6 8
0.84
1.68

99ab
100a
100a
100a
96abcde
99ab

91efg
93cdefg
95abcde
98abc
88g
94bcdef

95abcde
98abc
95abcde
99ab
96abcde
94bcdef

94bcdef
97abcd
92defg
98abc
89fg
97abc

94bcde
97ab
97ab
98ab
94bcde
97ab

96abc
96abc
97ab
100a
90de
96abc

95abc
97ab
92cde
97ab
96abc
95abcd

94bcde
97ab
95abcd
100a
89a
97abc

^ e a n s w ith in c a r r i e r volume and growth s ta g e fo llo w ed by th e same l e t t e r a re n o t s i g n i f i c a n t l y d i f f e r e n t a t th e
0.05% le v e l a s determ ined by Duncans M u ltip le Range T e s t.
^N orthern = Montcalm C ounty, M ichigan.

S o u th ern = B e rrie n C ounty, M ichigan.

121

Table 6. Effects of carrier volume and stage of growth at time of
application on Johnsongrass control 42 days after treatment with
non-selective herbicides in 1984 .

S e le c tio n ^
N o rth e rn

S o u th e rn
S tag e o f Growth

C a r r ie r Volume
H e rb ic id e

R ate
(k g /h a )

45-60
(cm)

Boot to Head

140
(L /h a)
G ly p h o sate
S u lp h o sa te
HOE-661

45-60
(cm)

Boot to Head

Jo h n so n g ra ss C o n tro l
(%)
0 .8 4
1 .6 8
0 .8 4
1 .6 8
0 .8 4
1 .6 8

75fg
87abcd
8 0cd ef
78defg
35k
85abcde

85a
97a
92ab
95a
85abcde
88abcd

78defg
77ef
83abcdef
77ef
77ef
70ghi

87abcd
87abcd
80 cd ef
82bcdef
82bcdef
80cdef

0 .8 4
1 .6 8
0 .8 4
1 .6 8
0 .8 4
1 .6 8

73fgh
50j
75f g
6 0 ij
27k
5 8 ij

78defg
98a
93ab
92ab
70ghi
92abc

50j
68hi
70ghi
68hi
6 0 ij
60j

78defg
82bcdef
78defg
80 cd ef
75fg
75fg

280
(L /ha)
G ly p h o sate
S u lp h o sa te
HOE-661

C leans w ith in c a r r i e r volume and grow th s ta g e fo llo w e d by th e same l e t t e r
a re n o t s i g n i f i c a n t l y d i f f e r e n t a t th e 0.05% l e v e l a s d e term in e d by
Duncans M u ltip le Range T e s t.
bNorthern=Montcalm County, Michigan.

Southern=Berrien County, Michigan.

122

Table 7. Effects of carrier volume and stage of growth at time of
application on Johnsongrass control 42 days after treatment with
non-selective herbicides in 1985 .

S e le c tio n ^
N o rth e rn

S o u th ern

C a r r i e r Volume
H e rb ic id e

S tag e o f Growth
R ate
(k g /h a )

45-60
(cm)

Boot to Head

140
(L /h a)
G ly p h o sate
S u lp h o sa te
HOE-661

45-60
(cm)

Boot to Head

Jo h n so n g ra s s C o n tro l
(%)
0 .8 4
1 .6 8
0 .8 4
1 .6 8
0 .8 4
1 .6 8

90abcd
90abcd
93ab
95a
81cdef
92abc

83 cd ef
78ef
88abcd
90abcd
63g
73f

97abc
93ab
86abcde
87abcde
88abcd
90abcd

83bcdef
83cdef
82cdef
83bcdef
73f
80def

0 .8 4
1 .6 8
0 .8 4
1 .6 8
0 .8 4
1 .6 8

93ab
97a
93ab
92abc
87abcde
90abcd

87abcde
87abcde
90abcd
90abcd
77f
83cdef

89abcd
89abcd
88abcde
90abcd
89abcd
83cdef

78ef
83cdef
80def
82 cd ef
87abcde
90abcd

280
(L /h a)
G ly p h o sate
S u lp h o sa te
HOE-661

^ e a n s w ith in c a r r i e r volume and grow th s ta g e fo llo w e d by th e same l e t t e r
a r e n o t s i g n i f i c a n t l y d i f f e r e n t a t th e 0.05% l e v e l as d e term in e d by
Duncans M u ltip le Range T e s t.
^Northern=Montcalm County, Michigan.

Southern=Berrien County, Michigan.

123

Table 8. Effects of carrier volume and stage of growth at time of
application on control of Johnsongrass regrowth one year after
treatment with non-selective herbicides in 1985a.

Selection**
N o rth e rn
C a r r i e r Volume
H e rb ic id e

S ta g e o f Growth
R ate
(k g /h a )

45-60
(cm)

Boot to Head

140
(L /h a)
G ly p h o sate
S u lp h o s a te
HOE-661

S o u th e rn

45-60
(cm)

Boot to Head

Jo h n so n g ra ss C o n tro l
(%)
0 .8 4
1 .6 8
0 .8 4
1 .6 8
0 .8 4
1 .6 8

97abc
100a
98a
98a
92abcde
95abcd

95abcde
88abcdef
88abcdef
78f
100a
97abc

84cdef
87abcdef
87abcdef
84cdef
85bcdef
8 2 ef

88abcdef
91abcdef
93abcde
91bcdef
92abcde
95abcd

0 .8 4
1 .6 8
0 .8 4
1 .6 8
0 .8 4
1 .6 8

95abcde
100a
93abcdef
97abcd
100a
100a

85bcdefg
83defg
85bcdefg
85bcdefg
80fg
95abcde

83defg
90abcdefg
97abc
91abcdefg
9 3abcdef
90abcdefg

78g
85bcdefg
91abcdefg
9 0abcdefg
86abcdefg
93abcde

280
(L /h a)
G ly p h o sate
S u lp h o s a te
HOE-661

^ e a n s w ith in c a r r i e r volume and grow th s ta g e fo llo w e d by th e same l e t t e r
a r e n o t s i g n i f i c a n t l y d i f f e r e n t a t th e 0.05% l e v e l a s d e term in e d by
Duncans M u ltip le Range T e s t.
^Northern^Montcalm County, Michigan.

Southern=Berrien County, Michigan.

124

Table 9. Effects of carrier volume and stage of growth at time of
application on control of Johnsongrass regrowth one year after
treatment with non-selective herbicides in 1986a.

S e le c tio n * 3
N o rth e rn

S o u th ern
S ta g e o f Growth

C a r r i e r Volume
H e rb ic id e

R ate
(k g /h a )

45-6 0
(cm)

Boot to Head

140
(L /h a)
G ly p h o sate
S u lp h o s a te
HOE-661

45-60
(cm)

Boot to Head

J o h n so n g ra s s C o n tro l
(%)
0 .8 4
1 .6 8
0 .8 4
1 .6 8
0 .8 4
1 .6 8

97ab
100a
100a
92abc
73e
92abc

93abc
93abc
92abc
100a
100a
95abc

93abc
95ab
92abc
83cde
83cde
95abc

98ab
97abc
100a
98ab
98ab
93abc

0 .8 4
1 .6 8
0 .8 4
1 .6 8
0 .8 4
1 .6 8

100a
93abc
100a
100a
97abc
97abc

97abc
98ab
92abc
97abc
100a
100a

78de
87abcd
92abc
100a
83cde
85bcde

95abc
100a
90abcd
95abc
95abc
97abc

280
(L /h a)
G ly p h o sate
S u lp h o s a te
HOE-661

^ e a n s w ith in c a r r i e r volum e and grow th s ta g e fo llo w e d by th e same l e t t e r
a r e n o t s i g n i f i c a n t l y d i f f e r e n t a t th e 0.05% l e v e l a s d e te rm in e d by
Duncans M u ltip le Range T e s t.
^Northem=Montcalm County, Michigan.

Southern=Berrien County, Michigan.

LITERATURE CITED

1.

Baird D.D. and R.P. Upchurch.
1972.
Postemergence
characteristics
of
a new
herbicide,
Non-0468,
on
Johnsongrass.
Proc. South. Weed Sci. Soc. 25:113-116.

2.

Banks,
P.A.
and
T.N.
Tripp.
1983.
Control
of
Johnsongrass
in
soybeans
with
foliar
applied
herbicides.
Weed Sci. 32:628-633.

3.

Chernicky, J.P. and F.W. Slife.
1985.
strain of Illinois sorghum to Tennessee
Weed Sci. 33:328-332.

4.

Colby, S.R., J.R. Bone,
and A.A. Akhavelo.
1982.
PP009, a selective herbicide for perennial and annual
grasses.
A b s t r . , Weed Sci. Soc. Amer., No. 24.

5.

Crawford,
S.H.
and
R.L.
Rogers.
Johnsongrass
control
in
soybeans
Proc. South. Weed Sci. Soc. 26:61.

6.

Duray, S. A. and G. Kapusta.
1978.
Germination and
viability of weed seeds after 2.5 years in a 50-year
buried seed study.
Weed Sci. 26:230-239.

7.

Hicks, R.D. and O.H. Fletchall.
1967.
Johnsongrass in corn.
Weeds 15:16-20.

8.

Langemeier, M.A. and W.W. Witt.
1986.
Johnsongrass
(Sorghum halepense) control in reduced tillage systems.
Weed Sci. 34:751-755.

9.

McWhorter,
C.G.
1971.
Control
ecotypes.
Weed Sci. 19:229-233.

10.

Comparing a
Johnsongrass.

1973.
Rhizome
with
glyphosate.

of

Control

of

Johnsongrass

Parochetti, J.V., H.P. Wilson, and G.W. Burt.
1975.
Activity of glyphosate on Johnsongrass.
Weed Sci.
23:395-400.

125

126

11.

Roeth, F.W.
1973.
Johnsongrass control in corn with
soil incorporated herbicides.
Weed Sci. 21:474-476.

12.

Warwick, S.I. and L.D. Black.
1983.
The biology of
Canadian weeds.
61.
Sorghum halepense (L.) Pers. Can.
J. Plant Sci. 63:997-1014.

CHAPTER FIVE

SUMMARY AND CONCLUSIONS

The morphology and dry matter production of two weedy
sorghum selections from Michigan were compared with that of
selections
Canada.

from

The

several

selection

other
from

locations

Berrien

in

County,

the

U.S.

and

Michigan

was

similar to selections included in this study which produced
rhizome able to overwinter in the areas they were originally
obtained

from,

Michigan was
unable

to

whereas

similar to

overwinter

obtained from.
plant

height,

the

selection

from

selections which produced

in

the

areas

they

Leaf width, leaf number,
and

rhizome

types were similar to

Eaton

dry weight

were

County,
rhizomes

originally

stem circumference,

of

the

overwintering

halepense whereas the non-overwin­

tering types were similar to

S.

alm u m .

There were distinct differences in the response of the
two

Michigan

Berrien

selections

County

type

to

temperature.

showed

superior

Rhizomes
tolerance

of
to

cold

temperatures relative to that of the Eaton County type.
outdoor

overwintering

studies,

127

the

rhizomes

of

the

the

In

Eaton

128

County type showed very little ability to survive at either
of two
were

locations whereas

able

southern

to

those

tolerate

location.

of

winter

Exposure

the Berrien

temperatures

to

OC

for

4

County
at

days

type

the
in

more
growth

chambers significantly reduced rhizome survival of the Eaton
County

selection

but

County selection.
possess

greater

southern

did

not

could

cold

tolerance

locations.

The

phospholipids

play

a

that

of

the

Berrien

The Michigan selections did not appear to

part

was

in

than

degree
:

membrane

effect

*

exhibited by the different

of

from

saturation

more

of

cell

if

this

•

examined

the

selections

to

determine

differential

types.

cold

There was

tolerance

no consistent

correlation between the degree of fatty acid saturation and
cold temperature tolerance.
ing

types

showed

greater

Rhizomes of the non-overwinter­
ability

to

sprout

at

lower

temperatures, however, seed germination was less.
Efficacy of several herbicides was examined for control
of

the

single

two

Michigan

early

postemergence
and

selections.

postemergence
herbicides

sethoxydim was

Control

application

fluazifop,

greater

at

the

provided

of

the

haloxyfop,
northern

by

a

selective

quizalofop,

location

where

infestations consisted mainly of the non-overwintering type
than

at the

southern

location where

mainly of the overwintering type.
in

control

provided

by

these

infestations

consisted

There was no difference

treatments

between

the

two

129

locations

when

application or
Control

of

treatments

were

as a single

regrowth

in

applied

as

late postemergence

the

year

following

a

application.

treatment

greater at the northern than the southern location.
of

these

two

herbicides

glyphosate,

examined.
when

selections

provided

sulphosate,

split

by

the

and

HOE-661

was

Control

non-selective
was

also

Control provided by these treatments was greater

applied

in

a

carrier

volume

of

140

than

280

l/ha.

Control was greater when treatments were applied at the boot
i

*

-

*

.

to head stage than when plants were 45 to 60 cm in height.
This
increase

study was

conducted

to

in the number of acres

investigate

the

apparent

infested with Johnsongrass

in the state of Michigan and to determine if this spread is
a result

of the

adaptation

cooler temperatures.
this

study,

that

Michigan exhibit

the

of

ecotypes

of Johnsongrass

to

It does not appear from the results of
ecotypes

of

any adaptation

Johnsongrass

present

to cooler temperatures

that much of the apparent spreading of Johnsongrass

in
and

in the

state can be attributed to misidentification of £3. almum as
Johnsongrass.

Based

on

the

results

presented

here

the

spreading of Johnsongrass by rhizomes in Michigan is limited
to areas of the
freezing

state where

throughout

temperatures

are

the

below

soil temperatures remain above

winter.

In

freezing

for

areas

where

extended

soil

periods,

infestations reported to be Johnsongrass are most likely S.

130

almum.

Spreading of both species by seed, however, must be

considered

as

both

£5.

halepense

and

£3.

almum

produce

tremendous amounts of viable seed each year and movement of
seed by equipment,
to

be

problems

a

major
have

therefore,

reason

increased

that

identification

animals,

growers

of

these

and in rivers and streams seems

infestations
in

the
first

weed

of

state.
obtain
species

both
It

these

is

important,

early,
and

weed

take

positive
quick,

aggressive action to control infestations before they become
major weed problems.