paper is to estimate the magnitude and the

Japanese Society of Grassland Science

JapaneseSociety ofGrassland Science

o

o

g.Japan^{Grassl. Sci.,18(4):}267N276(1972)

'

History

of

Local Strains

of

Timothy in Hokkqido

and

its Breeding Implications

Tohru

SHiMADA

and

Yoshisuke MAKr*

ObihiroZootechnicalUniversity

(Inada-choi

Obihiro-shi, Hokkaide) - ^* Hokkaido National Agricultural Experiment Station

(Hitsujigaoka,

Sapporo-shi,Hokkaido)

Introduction

The

ecotype or

locally

adapted population ^as

defined by TuREssoN'9) is

an

invaluable

source of

breeding

material

in

cross-pol]inated

forage

crops. 'Most

of the

forage

varieties selected in

Japan

^{have been}

^{derived from}

^{such ecotypes}

(MAKii4)).

^{This is true for}

timothy Hokkaido localstrains which perform ^well for hay er silage and have

been

used extensively as

breeding

^material.

Genetic

^{shift caused}

by

^{'natural selection}

during

the domestication of these strains appears to be largely responsible for its characteristics and

genetic

^{diversity. The purpose of this}

paper

^{isto estimate the magnitude and the}

nature of genetic ^shift

during domestication

and to evaluate the usefulness of these

strains for breeding materiaL

The short history of timothy cultivation in Hokkaido

is

^as

follows. The first

^cultiva-

tion of timothy

in Hokkaido

^was

done

experimentally

in 1874 by

^{using seed}

from

the

United States. Thereafter,

^{although seed was} introdused several times from the same country, ^{mainly seed} from these experimental

fields

in 1880'swas multiplied repeatedly and

distributed

throughout

Hokkaido. This.situation,

continued until

1960

when a

great

amount of commercial seed began to be

imported,

_produced localstrains that were well

,adapted to climatic conditions in

Hokkaido.

The superior performance ^of thisseed was recognized relatively early, although without any experimental evidence.

It

^{was named}

as

Hokkaido local

^{variety and} recommended

in 1914. Hokkaido local

^variety

is

^a _general

terrn for domestic seed which has

been

^maintained through seed production ^repeated for

commercial or

private

^{use inHokkaido. In more detailitis calred as ``Hokkaido local}

variety

Kunneppu

strain'',

In

thispaper ^we

designated

seeds which were collected

from

old pastures ^{and roadsides} in

Hokkaido

as localstrains.

Material and Method

Seeds from

18

local

strains collected from old pastures'^{and roadsides}

in Hokkaido･

and 27 varieties from overseas were sown in

f]ats

^{in late May} of ^'/1964. The seedlings were then transplanted to

field

_plots ^of the

Kitami Agric. Expt. Stan.

^{and spaced on}

ene meter centers.

A

^randomized

block design

with

four

replications ^{was used.}

Data

268 H

li " ^±

^ta

#k El.. M18

ig M4e

(1972)

were recorded

from 10plants in

each plot.

Plants lwere

^{measured and}

^harvested

^when

all plants ^{within a strain or variety} ,headed.

Aftermath from

all strains and varieties was cut on the same date in late september. Heading date, culm length, and ^seven other agronomic characters were evaluated for two successive years ^after the _year of

establishment.

Seed

_{yieldper plant} ^{was measured for}a

part

^{of the}

plants

^{of the fourth}

year. Leafiness, degree of rust

infection,

^and _plant type

l-were

^scored

^by

^{visual rating}

(scale

^of

^{1-9). Origin}

^{and number of strains and varieties examined are as shown}

ⁱⁿ

Table 1.

Table 1. 0rigin and number of Iocal^strains and introduced varieties

Localstrains

Somewhat improved^Land maintained 4

from ind.igenous_grasslands and roadsides 5

from lays for hay after 20years ^{or more since} establishment 2

from _{permanent pastures} after 20 to5e years ^since establishment 7 Introducedvarieties

from Nerth America ; Canada

(8},

^{United States}t4]

from Western Europe _;Netherlands

(s),

^GreatBritain(4),France(1) from Northern Europe ;Sweden

(2),

^Denmark

(1),

^Poland

(1)

from ^{others ;} New Zealand(1)

e･

h

Results

lntra-specific

Figure 1

variation

shows relativevariability of main agronomic characters

between lecal

strains

Table2.Mean with standard deviationbetween plants, and coefficient of of agronomic characters inlocalstrains and introducedvarietiesvariability

Mean ± S.D. c.v.

Characters

Local Introduced Local Introduced '

2nd

3rd

4th year

year

year

Heading date Stem number

Spikenumber

Leafiness Rust resistance

Forage yield

Heading date Stem number Forage yield

Seedyield

25 ± 3 148 ± 60 68 ± 25 4.7 ± L7 3.6 ± Ll 116 ± 25

31 ± 4 359 ± 93 337 ± 85

38 ± 16

35 ± 10 187 ± 90 83 ± 44 5.8 ± 1.7 5.2 ± L2

144 ± 30

42 ± 10 407 ± 190 257 ± 103

27 ± 20

124137223122

142636

44

284853292321

244740

74

es

Japanese Society of Grassland Science

JapaneseSociety ofGrassland Science

SHiMADA ^. MAKi: History of Local Strains of Timothy inHokkaido and itsBreeding Implications-I･[269

o

o

40

30

20

10

e

gge

40%al

30in9

2o2

:

^le

goE

40

30 20 10

o

r'=

lt

J

^L-1

F'

^r

1- i

F t

20 25 30 5 10

JUNE JULY

HEADING DAI"E

r-"l L--lt11

100 200 ,300 400

STEM

^NUMBER

r'-1

^ll

i L--

^t l

500 40 30 20

10

o

40 30 20 10 o

40

30

r'-T"411IlIi

2 ⁴ 6 8

LEAFINESS

(SCORE)

2 4 6 8

RUST RESISTANCE

(SCORE)

O,5 ^1.0 1,5 2.0 O ²⁰ 40 60 80

TO'IZAL^FORAGE YIELD

(Kg)

^{SEED YIELD}

(g)

Fig. 1, Distribution of relative frequencyof various agronomic characters in local strains

(dotted

^{line)and introduced varieties}

(solid

^line)

and introduced varieties. Although the results are shown only for plants in the second year, ^{similar results were} found for plantsinthe thirdyear. Local _{strains and} introduced

varieties differed significantly for all characters whereas

local

strains

differed

signi-

ficantly

only

for heading date

and stem number(Tables2 and

3). Apparently

the local

Strains had

^not

differentiated

^and theircharacteristics were

biased

toward the same plant type.

Generally

they

had

^earlier

heading date, lower

capacity of tirlering,

less leafiness,

poor ^resistance to rust

infection,

higher seed yield,^and

lower

forage yield^{under spaced} conditien.

They

also had _erect growth

habit, dense

aftermath

heading,

and yellowish thin leaves.

Although

^the introductions

from

overseas were not

local

strains but im- proved ^varieties, they were

inclined

to show plant types that correspond with each area

270 E 7S

S

^tu

#

^{ftts rg18 ts ag4e}

(1972)

Table. 3. Analysesof four agronomic characters in 28strainsD and varieties which were

^{cut on the same} date^{as early} _group

xMMr --ut-tL

Source

Heading Stem

d.f. date number

(day) (10

^stems)

Culmlength(cm)Total forage

yield

(10

g) Replications

Strain'sand varieties

(S)

Betwegn groups

Within introducedvarieties

Within^localstrains Error

(1)

Years

(Y)

sxy Error

(2)

Individualswithin plots

3 27 1 15 1181

1 27an896

34 602**5, 517**

667**

68**

21 1,O14**

16**

7

12

203*

325**

399**

472**

117*

57141, 300**

154

381

42

363 705**

721, 105**

217 2096, 940**

381**

124

87

134**

170**

1,518**

194**

15

2347,O09*l:

58**

12

16

pt

i

1) All of localstrains iscontaind inthis group

of

development. For

example,

the

plants

from

^the

United States

and

Canada

^showed

essentially the same upright growth

habit

as localStrains

but

^{they were sQmewhat later}

flowering,

and

had longer

and thicker culms with

large heads. On

the other

hand,

plants from the Netherlands and

Great

Britain were

decumbent,

conspicuously later

flowering, heavy

^tillering,and had a large proportion ^of leaves and relatively few culms.

Consequently, it is

_possibleto

divide

the strains and varieties

into four

main

groups;

i.^e., American, Western European, Nothern European, and

Japanese.

Intra-population^yariation

The

^{megnitude of variance among} plants ^{within each strains and varieties was one} of mgst ^striking featur.esof the present ^results. The variance was correlated with the

phenotypic ^{value and} the correlation coeMcient

between

^{mean value and standard devia-}

tion^{of each strain or varietywas} highly significant

for

all characters.

The introductions from

the

Netherlands

^{showed the largest} intravarietal diversity for al] characters, whereas the

local

^{strains were} the least variable. Introductions

from North America

･ _and

Northern Europe

^were

intermediate,

except Clair,the earliest variety from the United

States,

^showed the

least

^variations

(Fig. ^2).

Change

of temperature _and

daylength following introduction

^appeared to

be

the most

important

cause

for

these enlargement of variances, In a transplanting study ot timothy

clones,

EvANsdO)

observed that the

difference

of maturity was affected

by temperature

and

daylength,

ande ventually the variation of

heading date

and correlated characters increased

at southern

latitudes. In

^the present ^{study, all of} the

introduced

variety except those

from

the

United States

^{were collected}

from higher latitudes

^{than this location,44 degree}

N.

AgrQnomic requirement seemed to

be

^{another factor} influencing this phenomenon.

The

^{variation within} tbe varieties

from

the

Scandinavian

,countries ^{were smaller than}

-

"･

Japanese Society of Grassland Science

JapaneseSociety ofGrassland

SIMADA.

Science

MAKI:History of L?cal StrainsofTimothy inHokkaido _and itsBreeding Jmplicatiops27 1.

r

o

v

25 HEADINGDArl'E A

hoo'nALFoRAGEylELD

^A

A

A

A

so o

20Z･i9

A

/6t

is

oCAAA 40

eoe

ou:ooAAA

M O

E{ii

ooo ^oA

10

･k･t

ee

e

ee

s

2o 3e IQ 20 80 100 120 140' 16o lso

JUNE

^JU[Y

'MEAN

(10g)

MEAN

'

^{Fig. 2.} Relationshipbetween mean and standard deviationof locpl.strains^and introeuced

variet5es.

'these

from

the

Netherlands

^and

Great

^{Britain. Timothy is} valuable

for

permanent pastures ^and

long-tertn leys in

the

Netherlands

and

Great Britain (VAN ^{DiJK20'). But}

it is

^most'

important

^{for three or' four'}year leysinthe

Scandinavian

^countries

(QpsALi5').

In forage grasses,

^{the differencein manner of} cultivatiofi ,rr[ay^{cause a}

population

^to

･differentiate_{with respect} to th: optimal season of

flowering

^and

hence

the response to photoperiod

(CoopERS)).

^{For example, regular}

^harvesting

^{for hay or seed produces a}

'type'with

earlier and ^{more uniferm} heading, and shows smaller variability for heading and

flowering

^{date. Itis}

likely that

^thisalso ^{cause similar} tendency inother characters

which are correlated closely with

heading

and flowering. ･

'

Character

comelations .

A dual plant

^{type, either}

haY

or

pasture,

^is

quite

^{common inthe}

intra-specific

varia-

tion of

forage

_grasses.

This

makes

it

_possibleto express 'a

set of character combina- tions

by

a plant

type.

^For example; the chatacters, which are generally^{correlated with}

hay

type

in Lolium,

^are

large

seed,

low

tillernurnber,.

high

tillerweight, ^erect growth

habit,

^wide

leaves,

^early

flowering, long

^{stem, many aftermath}

heads, low

vernalization

requirement, and

high

topiroot ratio.

The

reverse

is

true

for pasture

^type

(FEJERii').

The

difference between

types was also

rioted for

timothy and they were expressed inthe same way as

for Lolium (Table ^4).

^'

^{Although no directevidence isavailable, the} envirgpmental conditions at this

loca-

tion

appeared

to

have

^acted to

increase

the

differences

among

types

^{and to} give ^more marked correlations

between

characters.

If･

this

is

true,the environrnent

in

this

location

272 H ]l!n'ⁱⁿ \k i,^±.

ee

¹⁸ ts

as

^{4 -taff}

(1972)

Table 4.Correlationmatrix of ninecharacters inlocalstrains and introducedvarieties

Characters X2 X3 X4 X5 X6 X7 X8 X9

Forage yield Xl Seedyield X2 Headingdate X3

Stem numbe.r X4

Spike nuipber.- X.5 Culm length X6 PIant type X7 Leafiness X8 Rustresi$tance X9

-.358* .661** .

-.736** -.700**572**- 43e**

.461** - ₁₂₄ .320* ²³⁰ .049 - 252 .813** - 107

097

559**

- _385*

617**

705**

431**

- ₁₂₀

.734**

-.411*

.900**

.415**

.157-.220

.412**

.633**, .551*lp

･69o*s

.348*

.106-.267-.636**'

.713*lp

Q

tends to intensifythe effects of natural selection and

facilitate

the

differentiation

^of

certain type at the _expense of others.

In forage

grasses, ^natural selection preduces

correlated responses fittingthese character combinations which are ^carled either hay _or pasture type(BRouGHAM et al.2],

CHALEs4), CoopER7}, FEJERii), GREGoRiS), STApLEDoNiS),

VAN DiJKflO,2i}).

There

are, however, a

few

reports which

indicate

a

deviation from

the character combination for

hay

or pasturetype(REBiscHuNdi6],FEJERti}). FEJERii]suggested

that

differentiation

^of the$e characters may vary according to change

in

genotype ^and environment. Intensified_or counteracted responses･ induced by environment have

been

known in

timothy populations

introduced

gla-tnnApt-bunmraen

20

30

^{10 20} 30

JUNE JUIJY

HEADING DA]]E

Fig. 3. Relationshipbetween headingdateand

^seed yield ^of local^{strains and} introduced

varieties

from differentarea(GoRMANi2),EvANsiO)).

In an experiment by EvANsaO), a change of temperature and

daylength from

nor-

thern latitudestothatof southern latitud-

es cause the

latest

selection to change

from

^{upright culms} to short

decumbent

culms, and

from large

^number of

fertile

infloresencesto sparse barren infloresen--

ces.

The

earliest selection, on the other

hand,

showed relatively similar growth habit at

bothconditions. Thesefindings

seem to

be

some explanations fer the

close correlations among characters in

our results.

The

^close correlation of seed yield ^and heading date

(r==.736)

shows the apparent disadvantage of late plant type(Fig.

3). Local

strains appea- red to be the most abundant seed

pred-

ucer under the environment of

Hokkaido.

'

t

di

Japanese Society of Grassland Science

JapaneseSociety ofGrassland Science

SiMADA.MAKi: History of Local Strainsof Timothy inHokkaidoand itsBreeding Implications 273

o

v

Discussion

Our

^{results showed} that

Hokkaido local

^strains _possessed ^character combinations

biased

towards the

hay

^type as a ^result of cultivation foracentury inHokkaido.

Origin

of seed stocks, management and use, and environmental ccnditions can

be

censidered as the important causative

factors,

^Hokkaido

local

^{strains were} established from comrnercial seed introduced from the

Uni･ted States

^since

1874. These

^{seed stocks showed} _probably the same character combinations

for hay

type as toda}r's

local

^strains. All varieties introduced

from

this,

country showed such characteristics

in

this experiment, and ^records of early variety testing of

intreduced

species of

forage

crops

have

reported similar performance.

This･

means that

increase in

variation

following introduction

and adaptation was srnall,

A

large

shift

from

one plant ^{type to another} isunexpected in the course of

domestication.

cf these strains.

In a population ^of cross-pollinated forage species, considerable genetic variability exists not only among individuals

but

also inthe

hetrozygous

^{condition within} individuals.

A

_populatien

is

ordinarily maintained within

its

original phenotypic ^range

by

stabilizing'

influences of the environment

(CooperS,").

^{when a} population is introduced into a

differentregion, they exibit considerable variation

(CoopER5,']). They

^therefore are ^able- to response to selection

far

^outside the

limits

^of the original population ,(CoopER5i6)).

These suggestion indicatedthat the characteristics of the locaL strains would depend.

Iargelyupon the nature of selection after the

introduction, In

perennial ^ryegrass of

New Zealand,

_quite

distinct

populations,perennial(pasture)type ^and

Italian(hay)type, had

evolved

during

the relatively shert time from the introductionof Britishcomrnercial seed

in

the 1880's

(BRouGHAM

^{et al.3'). Timothy was}

^{important for hay in Hokkaido. The}

species therefore was used

in leys for

seven or more years and the seed ^was harvested from these leys. This manner of cultivation favored the development of

hay

^type

plants-

Hekkaido

is

located

^at lower

latitudes

than ^{that of other countries}

frem

^{which seed}

was obtained, except

for

a part ^of the

United States,

and therefore

daylength

^isshorter through the

growing

^season

in

the timothy growing ^area, Especially in spring short.

daylength delays

the production ^{of culm and} infloresencesof

late

_plants.

Censequently,

their culms

do

^{not attain}

full length

^{and aftermath remain} vegetative.

Also,

^{the inflo-}

resences are apt to be sterile because of insufficient

development (SHiMADA

^and

^UEDAiT)).

Under

these conditions, the laterplants ^are disadvantageous not only in seed production but also in competition in the sward and will

be

eliminated

gradually

^{frem the popula-}

tion,and the population ^{will shift} towards the early

hay

type.

Low

temperature

in

early spring

is

another

factor

which reduces grewth. In

Hokkaido,

when the weather

has become warm enough for spring growth

(late

^{April), the daylength is} sufficient,

(14 hours) for

the

development

of ^culms and

infloresences

^{of early and medium} _plants.

Early plants produce ^{normal culms and}

infioresences

^with

12

to

12.5 heurs illuminatien,

whereas very

late

_plants ^require 15 heurs or more(EvANs and ALLARD'9',

ALLALD

and

EvANsi').

Accordingly,

early plants ^{with a critical}

day!ength Iess

than 14 hours

begin.

274 H 7ps!"'th\ k Skbag¹⁸ # ee⁴ -"e･(1972)

'

to

form flower buds

at the start of spring growth, although the

daylength

of 15 'hours,

that very

late

_plants require,

is

not attained until

late May. This

^difference

･(30day) _was the same as 'difference

in

mean

heading date betWeen

the earliest and

the latestpopulations ^of thisstudy.' Even if environmental conditions were favorable

for

early hay type to evolve natur'ally, itwould

be impossible

to expect a

large

^{shift to}

earlier

hay type, because

the

introduced

populations

from

the

United States

possessed 'the_same

limit

^{of earliness}

imposed'by

the

Iow

temperature

in

^{early spring of}

Hokkaido.

･On the other

hand,

the

sihift

to the

late

_pasture type _will never occur without 'continu-

ous artificial selecti'on.

The

^most

probable

^{shift which}

has

occurred

ih

the

process

^of

the domestication

might

be

towards

increased

proportion ^of plants ^within the population

･thatproduce ^{abundant seed, while'} the main characteristics have remained relatively

/t

iconstant. ' '

Success

in any bfeeding work which intends to utilize the performances ^{of natural}

/selection will largely

depend

upon the

paticular

^{nature of natural selection inthe location}

where

breeding is

_practiced.

Natural

^selection

in individual

_population ^which isremote

from

the center of origin of the species may proceed too

far in

r6sponse to paticular .localconditions. In such a population ^{a specific} plant type may

have developed

at the

･expense _of agr6nOmically important characteristics.

If

so, the usefulness of the popula-

tfon is limited'as

to'breeding material, and so the

introduction

^of _genetic ^Hdiversity

into

.the

breeding

_program

becomes

of'primary'importance･in order to provide for new

.geneticcombinations and ^maximum yieldand adaptation(CARNAHAN and

HiLL3)). Timothy

.is_{well adapted and} grows

flourishing in

climatic conditionS

in Hokkaido. But Hokkaido located'

near the southern

border

of the timothy

growing

^area

[-in

^{the nothern hemisph-}

･ere.

The

shorter

daylength

enlarges remarkably the

difference

of date of heading and

flowering between early and late

plants.''

^{This appears to}

^be

^{one of the most}

^important

factors which have developed the characteristics of Hokkaido

local

^strains.

In

this results,

Hokkaido local'strains

shoWed characteristics

biased

towards

hay

type and small

inter-and intra-strainvariation, and so they would have limited potential ^as breeding

unaterial. Itmay

be

_possibleto improve

[further [the

^{yielding ability of these strains,}

･because _{a number of success} in imprevement of forage

yield

^have

been

attained

by

using

/such ecotypes as

breeding

material.

But.[to

obtain

different

_plant types or, maximum

yield,itisnecessary to introduce new ･genetic _sources from overseas. In thisrespect, we may take advantage of natural selection by introducing material from regions of.the

United States

^where the environmental conditions are comparable to those of

Hokkaido.

But･the

characteristics of the

introductions from

that country, as shewn

in

this

experiment, are too similar to those of ･Hokkaido localstrains.

On

^{the other hand, the}

introductions from

the

Netherlands

and

Great Britain

seem to

be

more preferable

because

of their 'variation

and

different

_plant types.

Since

this experiment

did

not contain

introductions

^from

:Central

^and

^{Eastern Europe,}

^{the center of origin and} cultivation of thisspecies,

it is important

that they are evaluated under the condition of Hokkaido.

t t

' '

'

We

wish to express our thanks to

Dr. G. E. CARLsoN, Research Leader

of Plant

o

.

'

e

Japanese Society of Grassland Science

JapaneseSociety ofGrassland Science

SHiMADA^. MAK= Historyoi Local Strainsof Timothy inHokkaidoand ltsBreedingImplications275

o

Science

are also

helpful

Research

Division,U.S.D.A., for his invaluable advice and critisism. Thanks due to Professor K MuRAKAMi'of the

Obihiro Zootechnical

.Univerepity

for

^very'

suggestion.

Summary

We

compared the performances ^of

18 local

strains collected

from

old pastures ^and'

roadsides in

Hokkaido

with those ef 27 verieties from overseas. From these results, the, magnitude and the nature of shift caused by natural selection

during

^the domestication.

of tilnothyof

Hokkaido local

^{strains were estimated.}

Hokkaido local

^strains _possess.

character combinations

biased

towards the hay type. The

following

^{conditions were･}

considered to

be

responsible

for

this phenomenon.

(O ^The

^original /introductions,

frem

the

United States

^{seemed to}

have

the characteristics of the

hay

^type.

(2) ^Agrono--

mic selection, especially seed

production, favored

the

development

of

hay

type.

(3)･

Climatic

conditions,

daylength

and temperature ^'Lof early spring,

favored hay

type..

Becau'jie

ef these conditions we suggested that

the

shift which could

be

expected

during' domestication

^{might not}

be

a conversion of major-genic construction

but

_polygenic'

adjustment,

Namely,

^{natural selection}

favored

_plant

types that

produced ^{more se'ed,.}

while the main agronomic characteristics remained relatively constant. Because most' causative

factors

appeared to

be daylength

and temperature, the

Hokkaido local

strains, will

be

a climatic ecotype rather than an agronemic ecotype.

s

"

1)2)3)4)5)6)7)

8)

9)10)11)12)13)14)15)16)17)18)19)20)21)

Reference

ALLARD, H.A.and EvANs,M. W. : JlAgTic.Res.16,193

(1941)

BRovGHAM,R.W., GLENDAy, A.C. and FEJER,S.O. : N.Z.JLagn'c. Res.3,442(1960) CARNAHAN, H.L. and HILL,H.D.: Bot.Rev.27,1(1961)

CHARLEs,^{A.H, :} JLBrit.Grassl.^Sec. 16,69(1961) Coo?ER,J.P.:

JL

^{Ecologb,42,521(1954)}

^: Hleredity16,435(1961)

^: InCrop PlantEvolution,edited by Hutchinson,J.B., Cambride Univ. Press, London.

142(1965)

^: In Grasses inAgriculture, edited by Whyte, R.O., Moir, T. R. G.and Cooper,J,P.,.

FAO,Rome.223(1959)

EvANs,M.W.and ALLARD, H.A. : f.Agric.Res.48,571(1934) EvANs, M.W.: Amer.1;Bot. 26,212(1939)

FEJER,S.O.:Proc.XZh intern.Grassl. Congr., 618(1966) GoRMAN,L.W.: N.Z.

JL

^{Sci.Tech,32A, 1(1950)}

GREGoR,

J.

^{W. and SANsoME, F.W. :}

f.

^{Genet.17,349(1927)}

MAKI,Y.: SABRAO Newsletter 2,37(1970)

epsAHL, B.^: deldinger fra ^IVbrgesLandbrerkshipgsleole43,1(1964) REBiscHuNG,J. : Ann.Amel. Pl. 3,311(1953)

SHiMADA,T.and UEDA,S. : BzaJt.HblehaidoPrqfleet.^Agri. ExP.Sta.21C1970) STApLEDoN,^R.G.:

1:

^{Ecogegy 16,71(1928)}

TuREssoN,G.: Hereditas6,147(1925) VAN DuK, G.E.: EttPdytica4,83(1955)

^: Euphytica 10,43(1961)

(Recieved

^{on May 11, 1972)}

旧

草 地

^ユ8

_（

4）^：267〜276

_（

1972）

北 海道 に お け る チ

^{モ シ ー}

在 来 系統

^の

来 歴

^と

そ

^の

育 種 的意 味

嶋 　

田 徹 ・真

　

木

　芳 　

助^＊

帯 広

畜産

^大

学 （

^{帯 広 市 稲 田 町}

）

＊　

北 海 道 農 業 試 験 場 （ 札 幌

市

羊 ケ 丘 ）

　

北 海 道 ^に お け ^る 古

^い

草 ^{地 や} 路

傍

^か ら収 集 ^{し た チ}

^{モ シ}ー

の 18

系 統 と 海 外

^か

ら 導 入

し

た

27

_{品 種}

の

特 性 を 比 較

^し，

在 来 系 統 ^が 発 達 す る 過 程

^に

自然 選 択

^{に よ}っ て

受 け た

^{シ フ}

ト

の

大 きさ や 性 質 を 予 想 し た

。

　

^{働 在 来 系 統}

^{は ， い}

^{わ ゆ}

^る

^採

草

^型

^の特

^{性 を 示}

^し， 導

^入 品 種

^に

比 較 し

^て，

早 生

，

直 立 し

^た

少 な

^い伸

^{長 茎}

^，

^黄

味

^が

か っ

た 細

^い

少 量

^の

葉

，

銹 病

^に「

_{［ 隹 り易}

_い

_{性 質}

，_高^い

種 子 収 量

^お

よ び

個体 植^{に お}

^{け る} 低

^い

草 ^収

量

^を 示 ^{し た}

。

北

^{ア メ}

^リ

カ

や 北 欧

^か

ら

^の

品 種 は 在 来 系

統

^{と 類}

似

^な

特牲

^を 示 し た が

，

オ ラ

ソ

ダ や イ ギ リ

ス

か ら

の

品 ^種

^{は い}

^{わ ゆ る} 放 牧 ^型

^の 特

性 を 示 し た

。

　 ［

2

） 主 要 ^な 農 業 形 質

^の

系統 内 分 散

^は

導 入 品 種

^に

比 較 し

’て

在 来 系 統

^は

著

^し

く 小 さ

か っ

た

。

導 入 品 種

^に

は 導 入

^{に と}

も な う分 散

^の

増 大 ^が 認 め ら れ

，

そ の

傾 向

^{は オ ラ}

^ン

^{ダ や イ} ギ リ

ス

か ら

の 品

^{種 に と く に 大 き か}

^っ

^た

。

　

^（

³

^{） 形 質 間}

^に

^著

^し

^{く 高}

^い

^{相 関 が 認}

^め

^ら

^れ

^{た が}

^，

^そ

^の傾 絢

^は

^ラ

イ ^グ

^{ラ ス}

類

^で

知 ら れ

^{て い}

る も

^の

と 同 様 で あ

っ

た

。

北

海

^{道 の 気 象 条 件}

^，

^{と く}

^に

^{早 春}

^の

^短

^{い 日}

^{照 と 低}

^い

^{温 度 条} 件

，は こ

れ ら

の

相 関 を 強 め る 傾 向

^が

あ る

^と

考

^え

ら れ

^た 。 　

（

4

｝ 在 来 系 統 ^が

^{こ の よ}

う ^な 特 性 ^を 示 す ^よ う ^{に な}

^っ

^た 原

因

^{と し}

^て ，

素 材

の

性 質

，

導 入 後

^の

栽 培 様 式

，

と く に 採 種

栽 培^の様 式，^{お よ}

び 気 象

条件

^{が あ げ ら れ}

検

^{討 さ れ た}

^。

^そ

の結

果

，在来

^系

統

^が

発

^{達 す る} 過 程

^{に お こっ}

^{た と} 予 想 さ れ

る

変 化

^は ，

あ

る

草 型

か

ら他

^の 草

^型

^に

^{移 る と}

^{い っ}

^{た 大 き な} 変

化

^{で な く}

，

む し ろ 主 要 な

農業

^形

質

^{は あ ま り護 らず}

^，

^種

子 が 多産 ^な

^{タ イ}

プ

に機分

変

化^し

^{た と}

^{い っ}

^た 程 度

^の

も

の で

あ

っ

た ろ う と

考

^{え ら れ た}

。

　

〔

5

） 北 海 道

^に

^お け ^る 気 象 条 件 ^{お よ び} 従 来

^{の チモ シ}ー_栽

培 様 式

^は

と も

^に

農 業 上

有

利 な 形 質

^の

変 異

^の保存^{に は}

^{あ ま} り適 し

^てい

な

^い

^と 考 ^え ら れ

^{る の で}，

育 種 材 料 ^と

^{し て の}

在 来 系 統 は 限 ら れ た 目的

，

例 え ば

，

同 じ 草 型 を 持

つ ，

よ り 多 収 な 品 種

の育

^{成 に 利} 用 さ れ る

^べ

き

^で ，^よ

り 多 収

^で特

^色

の

あ る品 種 を育 成 す る た め

^に

は 海 外

^か

ら

^の

変 異

^の

導 入 ^が 必 要

^で

あ る

。

Q

恋