東部オーストラリアに自生するヒエ属植物(イネ科)の種多様性

The Society of Crop Science and Breeding in Kinki, Japan

The Society ofCropScience and Breeding in Klnki, Japan'

J.CropRes.55:13-

17

!!=

Research

Article

(2010)

Species

diversity

of

the

_genus

Echinochloa

(Poaceae),

native

to

eastern

Australia:

a

focus

on

their

habitat

and

the

threat

of exotic species

EijiTanesakai),[bmoko ohno2)and

Hirofumi

Yamaguchi2)

ODepartnrent

ofAgricultural

Scienceand 7lechnotogMFbcutty

ofAgriczalture,

KinkiVnivensity

(3327-204Nakamachi,Nara631-8505,Japan)

2)

Graduate

SchoolqfLifeand EnvironmentalSbience,OsakaPrefectureUhiver:sity

(1

m

1

Gakt]ericho,

Nakaku,

Sakai

599-

ss31,

Jqpan)

Summary: Thenaturai hal)itatof theEchinochtoaspecies _growingineastern Australiawas investigatedinMay 2008.Inthissurvey, fourannual native species, E dietrichiana,E inundata,E.telmatophila,and E,tumeriana, and threeexoticspecies,E.colona, E.6rus-galli,and E _polystachya,were observed. The native species clear]y

have

separate

habitats:

permanentstagnant poolsfbr

E.

dietrichiana,inlandfioodplains

for

E.inunclata,

in

or besidestreams forE,telmamphila, and inlandwaterceurses forE turneriana.Whilethehabitatof theexotic species _greatlyoverlap thatof thenatives, especially _perennialE,_polystachya,which formsmonospecific stands instagnant _poolsand inorbesidefioodrivers duetoitsremarkable _{productivity,}and E.crus-galli, which hasthe

potentialtoadapt to scveral moisture conditions. We _predictthattheinvasiveexotic Et:hinochloaspecies wil] become more and more threateningcausing serious

damage

tothenative species within

the

same genus,

Keywords: Echinochtoa,eastern Australia,habitat,native species, threat

lntroduction

The genus Echinochtoa,cemprising nearly

50

species,

is

distributedworldwide under differentclimatic conditions of

temperature and _{precipitation}

(Michael

1994,

2001).

This_genus ishighlydiverseinthe levelofpolyploidy, _growinghabit,and reproductive traits,facilitatingadaption toseasonal or temporal

climatic

fiuctuations

(Ylabuno

1966,

Tlanesaka

1986,

Aoki and

Yamaguchi

2oo8).

Overall,the climatic conditiens ef the

Australian

eontinent are characterized as aridtosemi-arid

in

inlandareas and tropicaltosubtropical monsoon climate in northem coastal areas, Exposureof _plantson this_{geographically} isolatedconiinent tosevere droughgsudden fireor fiooding,has yietdedunique speciation of many taxa,Here,nearly twenty

Echinochtoaspecies have been recorded including

8

native species:

E.

dietrichiana

Michael,

E elliptica MichaeletViekery, E. in"nclataMichaelet Vickery,E.kimberlayensisMichaelet

Vlckery,E,lacunaria

_(Muell.)

MichaeletVickery,E macrtmdra MichaeletVickery,E,tetmatophilaMichaeletVickery,and E.

turneriana

_(Domin)

Black.Ib show thedistributionof each species, a detailedmap of thecollection site isavailable on the

AustralianPlantCer;suswebsite

(http:/twww.anbg.gov.aulchahl

apcD orthePlantNet,NSW FIoraOnlinewebsite

(http://plantnet,

rbgsyd,nsw.gev.auf).

All

the

above

species are considered tobe

annual

(Michael

1975,1980a).

Acccepted :April 16,2elO

Correspondingauthor : EljiIhriesaka

([email protected])

Tbappreeiate thespecies diversityof Echinochloarelated to

natural habitatand reproductive habit,a

field

survey

in

eastern

Australia,New SouthWalesand

Queensland

was carried out in May

2008;

fortunatelMan effective rainfaIl fe11thatsummer after several _yearsofsevere clrought.ProfessorPeter

William

Michael

(Sydney

University)accompanied us duringthistripto cenduct

thesurvey. Thisreport

documents

and

discusses

Echinochloa

species observed inthistrip,Here,we elucidated a threatto

natives under competition

between

species within the same

gelnus. Natlvespecies

E.dietrichianaR WLMichael

This species is annual, distributedin coasta1 areas of

Queensland

and theNorthernTbnitory

(Michael

1999).

The

epithet comrnernorates Amalie Dietrieh

(1821-1891),

a skillfuI collector in the

1860s,

for two of her specimens frem Rockhampton and near Mackay

Ovlichael

1999).The numbers of

documentson thisspecies hasbeenvery few

based

on awebsite

search frorn1926 to the

_present

_(Australian

New CrepsWeb Site,http:11www/newcrops.uq.edu,aul),In thissurveM ina perrrianeniswamp at Yeppoon Wetlands

beyond

Capricornia

InternationalResort,

_Queensland,

a few slender _paniclesand

leaveshadernerged above thewater surface toward thebank.

Almost

al1

parts of the procumbent eolumn up to

2

m long, branchingfromnedes with adventitious roots, were submerged

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rather small

due

tolowerdensityofpanicle branchescompared withE crus-galli er E,telntatophita,suggesting

this

species to

be

pseudo-allr;uag.The habitatof thisspecies lookssimilar to

that

oftheexotic E._polystuchya.

E.inundataR VVLMichae}etVickery

This species isannual, distributed

in

New Seuth Wales,

Queensland,

and SouthAustralia

(Michael

and Vickery

1975),

The plantgrows

in

or near watercourses or lakesusually followinginundationafter

flood

rains.In thissurvey, beside NarranLake,Nonh WesternPlains,New SouthWhles,about

10

plantswere _grewinginancl besidea marsh with a depthlessthan 40cm. Plants were erect or erectly spreading up to 160cm tal1,

often with shoots

branching

upward

from

submerged

lower

nodes with adventitious roots. Seed sets were _good on any individual_plant,Here,sorne aquatic _plantswere also_growingin marshes

(i.e.,

dyriophyllum

sp., Seshaniacannabina

(Retz.)

Pers,,and

dyperus

sp,) and on moist bedsoftextured soil

(i,e.,

1[tz)lygonumsp.,fortulacasp., and Oxalis_perennansHaw,),The climate of Narran Lake issemi-arid with an average annual

rainfa11 of

358-425

mm. Themonihly rainfalt isyariable, with a 1argersummer, butalso a winter_peak.Conditionsof lessthan

250

mm of rain often occur over a three-yearperiod,causing droughtconditions

_OfcGann

etal.

2co1),

Vickery

₍₁₉₇₅₎

citeda

note bearingon a collection by CaptainShortat theBritish Museum

_(1835-1836),

about aboriginal use of itsseeds forfood

in

theNorth

West

Interier

and theabundance ofthe _plantsinthis area,

Prof

Michael

toldus thatnativepopulationsalso use the

tuberous root of C]xalisperennans, suggesting thatfloodplains would befavoritesites tofindfood_plantsforthe_gatherers.

E.tehnntophila R

W.

MichaeletVickery

This species

is

annual,

distributed

in

New South Wales,

Queensland,

and WesternAustraHa

(Michael

and Vickery

1975,

Vickery

1975),

It_grewsinor beside_pondsand streams. Inthis

survey, Nindigully,

Queensland,

indensestands along banksof

'

irrigation

channel,

_plants

hademerged fromslighrly

below

water

'

level.Here,some aquatic

plants

grew

together

just

belewthe water surface

(i,e,

Ecliptasp.) and on moist banlcs

just

above water

(Le.,

Altemantherasp,, Chlorissp. and Cyperussp,), In Urbenville,New South Wales, this_plantgrew}forming a compacg dense_populationon moist sediment of streams, Both

the

habitat

and themorpholegy ofthisspecies resembled thatof exoticE.erus-galli,

E turnehana

(Domin)

J.M. Black

Thisspecies _isannua1, distributedinNew SouthWalesand

Queens]and

(Michael

and Vickery 1975,Vickery 1975).The

plantgrowsinornear watercourses. _In

this

survey,thisspeeies was observed on Mr,and Mrs,Pagett'ssheep-graxing property,

"Winrae:

near Barringun,N'ew South Wales, Only ene

individual

_grew

in

a

bore

drain

subjected to

flooding

in

the

last

sunimer rainfa11, Mr.Pagettsaid that

he

had

not seen

.th,lfi. plant

along the drainsince big rains seven _yearsearlien His observation indicatedthattheburiedseeds ofthis _plantcould be viable atleastseven _yearsinsemi-arid conditions. Alongthis

drain,

oneindividuatofE crus-galli was also found.

Exotic

species

E.colona

(L.)

Link

Thisspecies

is

annual, natiyetotropicalregions

in

theOld Wbrld,butnow widely distributedarollnd Australieqfoundin abundance on _grasslandand disturbedsites such as roadsides and

dry

creeks subjecttopergodic

fiooding

in

summer rainfa11

(Vickery

1975).

The _plantusually _growssingly or

diffusively,

witha

few

individuals,on rather drysoil inAustrali4tropical

Asia and the UniteciStates,but occasionally forrning monospecific compact stands en wet soil sediment fotmedatthe mouth of smal1 streams intofloodrivers; thelatterstandswere observed inPapua New

Guinea

in

_partof

this

_preject

in

October

2oo8.

E.crus-gaUi

(L.)

Beauva

Thisspecies

is

annual, considered to

be

nativetoEuropeand

Asia,butnow widely distributedintemperate reglens of the

world includingAustralia.Thisspecies hasbeenestablished as a

common summer-growing weed ofrice

fields

and other

disturbed

orenriched moistsites

in

nature

(Vickery

1975).

In

this

trip,near asubtropical rainforest inLegume,New SouthWlaEes,the_plant grew on riverside sediments together with ether aquatic _plants such as fotygon"tnhydmpiperL,,Comrnelinasp. and Clyperus

sp,

The

vegetation surrounding this_plantissimilar tothose

in

or

besidestreams er abandoned rice fieldsinJapan,

'

'

'

'

E.craspavonis

(Kt!irth)

Schult.

Thisspecies isaiiarmual toshort-Iived

_perennial,

native to SouthAmerica,extending northwards intothesouthern United Statesas a weed of r{ce fields

(Vickery

1975,

Michael

2003).

It was introducedintoAustralia,naturalized inNew South

Wales,

Queensland,

Victoria,and Western

Australieq

found

as an

occasional weed of cultivation

_(Vickery

1975).

Althougl!this plantwas not observed on thistrip,Prof Michaeldonateda specimen ofE. crusy)avenis collected atCam,den

_(near

Sydney), New SouthWales,inJanuary

1970,

with thecQmment thatthis specimen matches thetype material collected inSouthAmerica, A _photoof thisspecimen hasbeen attached as an appendix,

showing theconspicuous characteristics of thisspecies, which hasa lemma with

3-

te

iO-mm

Iongfiexueseawn. VVletherefore

deducedthatsome speeimens identifiedas E.cniszpavonis that we examined

in

Mississippi,USA, and _plantmaterials collected 14

The Society of Crop Science and Breeding in Kinki, Japan

TheSociety ofCrop Science and Breeding in Kinki, Japan

Speciesdiversityof the_genusEchinochtoa

(Poaceae),native

toeastern Australia:afocuson theirhabitatand thethreatefexotic species

as E,crus:pavonis fromLouisiana,USA, inpartof this_preject

in

August

2oo7

_(Sago

et

al

2008,

Ihnesaka

etal

2008),

were

misidentified,

because

these collections were characterized as

havingrather straight or tapered

long

awns up to

20

mm

long.

E _polysincltya

(Kunth)

Hitche.

(syn.

E.

_praestans

R WLMichael)

This species isperennial, native to tropicalto subtropical regions of SouthAmerica.It

has

been

introdueed

toPapua

New

Guinea,

_Queensland,

Northernferritoryand New Sou,thWales

and was

described

asE _praestansbyMichac1

_(1980b).

Inthe

Amazon

floodplains,

this

_plant

shews afloatinghabit,

_growing

up to

10

m ta11,with a heightcorresponding tothe

rising

flood

water level,and steady elongation at

I.1

m

per

month; itachieves an annual net _productionof dry mass exceeding

99

Mgtha

(Piedade

etal

1991).

Thefloatingability ewing totheremarkab]e

productivityof

this

species isequal to thatof thehexaploid Africanstrains ofE,stagnina

(Retz,)

Beauv. butismuch higher thanthatof the tetraploidtropicalAsianstrainsofE.stagnina and the 14-ploidE. _picta

(Koen.)

Michael

(Yhbuno

I966,

1lanesaka

1986,

1991).

This

plant was irrtroducedinto

Queensland

in

the

1ate

2orh

century asapotentialpondgrass

for

use

by

the

_grazing

industry.

In

Australia,

seeds were often completely sterilebutthe_plantvigorously

propagates

bynodal

shoots, rhizomes, or fragrnentsof shoots or rhizomes. Inthis survey, on the cattle-grazing _{propertM"Eden} GarTy",near Marlborough,

_Queensland,

ff._{polystaclryagrew} formingdense

stands

in

artificially ponded pastureswith wateg at thetimeof

inspection,

60

cm or more

deep,

Here,Brachiariamutica

(Forssk.)

Stapf_grew adjacent toor sometimes mixed with the

stands, and Ilymenachne amplexicaulis

CRudge)

Nees _grew

separatelyat

the

centerofthepond,

also

forming

monospecific

stands. E._polystachyaisas a

high

_prioritythreattonorthern Australiadue to itsinvasivecharacteristics as _pointedout elsewhere

(Humphries

et al

1991,

Csurhesand Edwards

1998).

Infact,on theFitzroyRiverinRockhampton,this_ptarrtoecupied

fiooded

laggons,forrningmonospecific stands thatappear to exceed

the

competing

Brachiaria,

Threat

of

invasive

Ebhinochtoa

Figure

1

shows a schematic representation of habitatof

Echinochloa species in eastern Australia related _tomoisture conditions. The native species havehighlyspecialized toadapt to

localenvironmenta1 fluctuationscausing semi-arid conditions over several _years,

fires,

and sudden

flooding.

CensequentlM

the native species are more clearly separated

from

each other

in

their

habitatbutoverlap with thatof exotic species

(Fig.

1).

Inthe longterm, thenative species is

_guaranteed

to withstand any

environrnenta1fluctuationonthiscontinent,However,byehance,

favorable

cenditions may allow exotic species te_quicklyspread

beyond theirnatural _populationand outcompete thenative species, atleastintheshort term.

Inthissurvey, E._polystachyaformeddensestands on stagnant poolsftworedbynative E

dietrichinna,

and on floodriversides

favored

by E, temiamphila and E. inundottt.Inthecentral

Amazon, E._polystachyacommonly formsmonospecific stands, suggesting thatitoccupies a niche thatno other _plantcan

occupy; this

habit

has

been

deduced

from

theobservation that

this

_plant

has

remarkable _productivityand acapacity to

invest

rnest of itsenergy intoshoot _growtli

(Piedade

et al

1991).

Humphrieset al

(1991)

listedthisspecies as ene ofAustralia's

topenvironmental weeds and recommended urgent action of its control and a review of thecurre/nt _{plantingpolicy,}Seven_years

lateg

Csurhes

and

Edwards

(1998)

stated

that

"total eradication may no

longer

be

feasible,

and action should

be

taken to_preveat

7-continued spread

.

Insouthem _partsof the UnitedStates,this planthas been established as one of the most troublesome

invasiveweeds inricefields,especially inthoseintendedfor second-crop _productionafter resprouting in_{permanentpaddy} conditions

(Webster

et al

2007,

Sagoet al

2008,

Tanesakaetal

2008).

The widespread E. crus-gatti isalso invasive.E.cnts-gaUi

E.crus-galli'

<e--->

E,polystachya"

-<f----L-TTH"---"---ii----J---F"m->

floodusual

E,

inundata Fig.1 a

Watercourse

Stagnant

HabitatsotEthinochroa species related to soil moisture and floodingevents ineastern Australia.

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The Society ofCrop Science and Breeding in Kinki, Japan

J.CropRes.55(2010)

growthclosely overlaps E,telmatophita inmoist coasta1 areas,

and occasionally also

E,

tumeriana

in

much drierinlandareas.

E,

crns-gatli ishexaploidand consists of two subspecies, themore

temperate E,crus-galli ssp.crus-galli and the more _tropica]E crus-galli ssp. hispiclata

(Retz,)

Honda

(Michael

2001).

The formersubspecies intemperateAsiaconsists ofthreevarieties: var. crus-galli which _grows inshallow water or moist soil, vai:

,formosensis

Ohwi

which

_grows

in

_paddy

fields,and var._pn ticola

Ohwi

which _growson moist orrather

dry

soilindisturbedareas

(Yahuno

l975,

1983).

In

addition,

there

is

acultivated

derivative,

E,

esculenta

(A.

Braun)H,

Scholz;

syn,

E

utilisOhwi etYabuno,

ineastern Asia

(Yabuno

1962,1%6, 1987,Scholz

1992).

Such a 1arge

diVersity

inthis_genome setsuggests aremarkable _potential toadapt toamuch wider range of environmental conditiens. This

species or species group islikelytocontinue te spread and threatenAustraliannatural _populationsby supplying new

genotypesfromthesource _poolofthe Eurasiancontinent.

TheAustratianEchinochtoareminded us ofDarwin's histerical

ti

insight:Asthespecies ofthe sarne _genususually have,thoughby

no means

invariably,

much similarity

in

habits

and constitutioq and always instructure,

the

strugglewill _generallybemore severe betweenthem, iftheycome intocornpetjtion with each other, than

betweenthe species of distinct_genera"

(Damin

1855;

inChap III).Some exotic Echinochloaare invasivedue to higher productivityand plasticity,and to

targer

genetic

diversity

compared to native species. They threatenserious damage, especially tothe native Echinochloa_populations,becausethey tendtocompete forslmilar resources within thesame _genus.

Acknowledgement

We thankProfessorPeterWilliamMichac1and hisdaughteg Diana,for_{pinpointguidance}en thefieEdwerk duringthissurvey

trip.We are again gratefulto Pro£ R WL Michael forhiskind

commenis

including

his

new opinions on Echinochloaspecies on

the

manuscript.

This

research was supported by

the

Japanese MinistryofEducation, Culture,Sports,Scienceand Technology, Grant-in-AidforScientificResearch,Ne, 19405017

_(supervised

byH.YainaguchD.

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The Society of Crop Science and Breeding in Kinki, Japan

The 　Sooiety 　of _{Crop 　Soienoe}and 　Breeding _{in 　Kinki}

厂

_Japan

Species　diversity　ef　the　genus　Ecゐinochtoa（Poaceae）

，

　na 恒ve　to　eastem 　Austra監ia：a　focus　on　their　habitat　and　the　threat　of　exotic　species

　

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］In： Naturat　History・

f

σ enUS 　Echin・chl・ α_，

　

（superv量sion　by　Yabuno_， 工 and 　ed

．

　by　Yarnaguchi_，　H

．

）

．

　

Ze  okyQ 　Shuppan　Publ

．

，

　Tokyo ，　pp

．

1

−

_{10 （in　Japanese）}

_．

Vickery

_，

　J

．

　W

．

1975．

　Echinochloa　Beauv

．

　ln_：Ftora_ofNew

South

　陥 ’es

_，

　No

，

19

．

Gramineae

，　Supplement　to　Part　

1

，　Part　

2

　（ed

．

　By　

Vickery

，　

J．

W

） 　New 　

South

　Wales　

Depar

仁ment 　ofAgricuhure _，　pp

．

189

−

211

．

Webs

重er

，

　 E

．

　P

，

　

Gri

笛 n

，

　R

，

　M

．

　and　Bounin

，

　D

．

　

C．

2007

，

　Management　of　Echinochtoa　polystachya　in　

dri11

−

seeded　rice

．

　doi：

10．

1094

！CM

−2007・

0816−01−

RS

．

　http：〃www

．

_{plantmanagementnetwork}

．

org ！_pub〆cm ！

　research ！

20G71drill1

Appendix 　l　Specimen 　of　E

．

　crus

・

・

_pav（）nis　colleCted　at　Camden _（near 　Sydney _｝

，

　New　South

　 　 　 　 　Wales　in　January　1　970

，

Note　the　3

−

to10

−

mm long

flexuose

awn

．

　 　 　 （Specimen　kindly　donated　by　P

．

　W

．

　Michael_＞

東 部

オ

ー ス

トラ リ

ア

に

自生

す る

ヒ

エ

属

植物 （

イ

ネ科 ）

の

種 多様性

：

特

_に

そ

の

生

息

地 と

外来種

の

脅威

に

つ い

て

種 坂 英 次 D

・

大 野 朋 子 2｝

・

山ロ裕 文 2） 1＞ 近 畿 大学 農学部 農 業 生 産 科 学科 （奈良 市 中 町

3327− 204

） 2〕 大阪府立大学 大学院生命環境科学 科 （堺市学 園 町

1 − 1

） 要 旨 ：オ

ー

ス トラリア東部に生 育す るヒ エ 属植物の生 息状 況につ い て

，

2008年3月に現 地 調 査 を 実 施 し た

，

本 調 査にお

い て

t4

種の

1

年生 在 来種

，

　E

．

　dietrichiana

，

　E

．

　inuncinta

，

　E

．

　te｛matephila

，

およ びE

_．

　turneriaua

，

およ び

3

種の外 来 種

，

　E

．

cotona

，

　E

．

　crUS

−

galli

，

お よ びE

．

　polystachya

，

を観 察 し た

．

在来種は 互いに生息地 を 異にしてお り

，

　E

．

　dietrichiana_{は 常 時 冠}

水 状 態 に あ る 沼 地

，

E

．

　intmdata_{は 内 陸}の氾 濫 平 原

，

　 E 屠  ∫op ゐ跏 は 小 川の中 お よ び その近 く

．

E

．

　turneriana_{は 内 陸}の水 路に そ れぞれ自生し ていた

．一

方

，

外 来種の生息環境は在来種のそれ と大 きく重 複し て お り

，

特 に

，

大 き な 生育力に よっ て沼 地や氾 濫 河 川 に 独 占 的 な 単

一

集 団 を 形 成 する多 年 生 種 E

．

　polystachya

，

お よ び幅 広い水 分 条 件に適 応 する潜 在 能 力の 高い E

．

crus

−

_galliに おい て顕 著であっ た

．

侵 略的 な外来種は特に同属の在来種に対 して深 刻 な 脅 威を与え 続 ける であ ろ う

，

キ

ー

ワ

ー

ド：ヒエ 属 植 物

，

東 部オ

ー

ス ト ラ リ ァ

，

生 息地 在 来種

，

脅威 　 　 　 作 物 研 究 　55 ：13

−

17_（2010_）