Agnc. Rev., 25 (1) : 1 -~5, 2004

'STATUS OF CITRICULTURE IN NORTH EASTERNREGION OF INDIA - A REVIEW

D.K. Hore and Utpal Barua

NBPGR Regional Station,Barapani, Meghalaya - 793103, India

ABSTRACTThe North Eastern region comprising of eight st~tes holds a unique positiQn in the world map of

Citrus occurrence and diversity. This region holds 17 species, out of which 8 are indigenous to thisregion. Despite of being a natural home and possessing wide diversity of Citrus species, none of thesestates, Citrosproduction and productivity figures could make a significant impact on the national averageof Citrus production. In this review work, the occurrence, distribution; their economic importance,problems and prospects of the Citrus cultivation in this region have been discussed.

The genus Citrus belongs to familyRutaceae and sub family Aurantioidae,consisting of large number of species andvariety. The closely related wild generas ofCitrus are Atalantia, Severinia, PonciJUs andFortunella. A few of them are used as rootstockfor citrus cultivation. Among fruits, Citrus hasgained a separate dimension due to its giganticindustrial expansion the world over. Citrus isgrown in tropical and subtropical regions ofthe world and occupies a wide range of latitudeover which it is being cultivated. With the effortsof modernizing Indian economy, the Citrusfruit, which has increasing market demand inadvanced countries, can play an important rolein boosting the developmentof fruit processingindustries as well as export for marketing. TheNorth Eastern states of India offer tremendouspotential in this direction. Systematic study,large scale cultivation and skilled managementpractices are'required for promoting the·Citrusbased induitry, in the country.

GENETIC RESOURCES OF CITRUSIt is believed that most of the species

under the genus· Citrus are native to tropicaland subtropical regions of South East Asia,particularly, India, China and in the regionbetwe~n the two countries. The North Easternregion of India stretches from 21° 57' N to29° 28' N and from 89° 40' E to 97° 25' E, isconsidered as one of the natural home of citrus.Ol,lt of total Asian Citrus, 17 species are found

in North Eastern region of India (Bhattacharyaand Dutta, 1949). Of which, only 8 speciesare indigenous to this region. They are Citrusaurantium L.; Citrus kama RafL; Citrus./imoniaOsbeck; Citrus indica Tanaka; Citrus limon (L.)Burm.; Citrus megaloxycarpa Lush.; CitrusassamensisDutta and Bhattacharya and' Citrusichangensis Swingle. Besides above, Kokaya(1983), reported 5 (five) new species fromHimalayan region, which extends upto China.These species have every possibility to occurin the state of Arunachal Pradesh, as the stateis a contiguity of Himalayan belt. However, thisstatement is subject to exploration andcollection of the species. These are CitrusjukoKokaya, Citrus serotina Kokaya, Citrus kinosaKokaya, Citrus sechen Kokaya and Citrustanaka Kokaya. TheTable 1 depicts the centerof origin and common names of the Citrusspecies found in this region. According to Kaul(1981), there are 17 species with 52 varietiesofCitrusoccurring in this region. Most of themare diploid and having chromosome no.2n=18.Federov (1974) also confirmed andsummarized the chromosome number ofdifferent Citrus species. According to him, thespecies like Citrus macroptera, Citrus limetta,Citrus karna, Citrus aurantium, Citrusichangensis and Citrus assamensis are diploid,while different ploidy levels are reported in thespecies like Citrus reticulata (18, 36); Citrussinensis (18, 27, 36); Citrus limon (18, 36);

,

Tab

le1;

Com

mon

nam

ean

dce

nter

ofor

igin

ofth

eQ

trus

spec

ies

foun

din

Nor

thE

aste

rnre

gion

Spe

cies

O"t

rusr

etic

ulat

aB

lanc

o.C

itrus

sine

nsis

Pers

.C

itrus

mac

ropt

era

Mon

tr.O

"tru

sjam

bhir

iLus

h.C

itrus

indi

caT

anak

aC

itrus

limet

ta(R

isso

.)L

ush.

Citr

uslim

on(L

.)B

urm

.O

"tru

smed

ico.L

.O

"tru

saur

antil

olia

(Chr

istm

.)Sw

ingl

eO

"tru

skam

aR

affin

.O

trus

aUTa

Iltiu

mL.

Citr

usm

ega/

oxyc

arpa

Lus

h.C

itrus

gfan

disn

:..)

Osb

eck

Citr

usic

hang

ensi

sSw

ingl

eO

trus

assa

men

sisD

utta

and

Bha

ttach

arya

Citr

us!a

tipes

(Sw

ingl

e}T

anak

aC

itrus

Bm

onia

Osb

eck

Com

mon

nam

e

Man

darin

Ora

nge

Swee

tOra

nge

lVa\e

ncial

Satk

ara

Rou

ghL

emon

Indi

anW

ildO

rang

e(M

eman

gN

aran

g)Sa

rbat

i Um

eA

ssam

Um

onC

itron

Kag

zilim

eK

ama·

Kha

ttaS

ourO

rang

eSi

shup

haI·

(Bar

teng

a)Pu

mm

eIo

Ieha

ngA

daJa

mir

Khas

iPap

eda

Ran

gpur

Um

e

Cen

ter

ofor

igin

Phili

ppin

eso

rC

ochi

nC

hina

/Sec

onda

ryce

nter

Japa

nC

hina

/Cci

<;hi

nC

hina

.N

orth

Eas

teni

Reg

ion

ofIn

dia

Poss

ibly

Indi

aN

orth

East

ern

Reg

ion

ofIn

dia

Tro

pica

lAsi

aEa

stof

Hin

laIa

ya,

Npr

thM

yanm

ar,S

outh

.Chi

naln

done

$ian

Arc

hlpe

lago

lNor

thIn

dia

Ind~

Arc

hipe

lago

lNor

thIn

dia

Eas

tern

Reg

ion

ofIn

dia

Asia

/Coc

hin

Chi

naN

orth

Eas

tern

Reg

ion

ofIn

dia

Sout

h.E

astA

sia

Sou

thW

est,

Cen

tral

,W

este

rnC

hina

.N

orth

Eas

tern

Reg

ion

ofIn

dia

Hills

ofM

egha

Iaya

and

Nag

aIan

din

dia

and

Sri

Lank

a

~ ~ 2 ~ i (f)

Vol. 25, No 1, 2004 3

Citrus medica (18, 27); Citros aurantifolia (18, found to confined in the Jampui hills of Tripura.27); Citrosgrandis(18, 36) and Citruslimonia They also reported the occurrence and(18,27,36), industrial use of C;itrus macroptera in the

North Eastern India can be broadly region, Singh et aJ. (2001) reported thatdivided into three well defined topographical Cherrapunji and Shella area of East Khasi hills

'th d t th d'st 'b· ti f /"'t and Jowai area of Jaintia hills are the potentialzones Wi regaJ1 0 e 1 n u on 0 . vI rusvarieties, These zones are (1) the high altitude areas for Khasi Mandarin, They collectedregions of the hills ranging from 1000 m to endangered species like Citrus Jatipes. Citrus

assamensis, Citrus megaJoxycarpa from the2700 m, (ii) the submontane tracts from 70 m Muktapur area of Jaintia hills of Meghalaya.to 1000 m, and (iii) the plain districts below Citrus macroptera and Citrus Jatipes were

.70 m, The specl'es whl'ch· are generally fo.undreported to be growing in semi-wild form at

to grow in the high altitudes are (i) Citrus altitudes below 500 m and above 900 michangensisSwingle, (ii) CitrusJatipes(Swingle) respectively. Areas bordering to BangladeshTanaka, (iii) Citrus indica Tanaka, (iv) Citrus have greater variability for pummelo (Citrusmacroptera Montr, and those grow usually in grandi~, satkara (CitJ/l'i macroptera) and citronthe plain areas are (i) Q'trusmedicaL, (ii) Citrus (Citrus medka). while in Kamrup district oflimon (L.) Burm, , (iii) Citrus aurantilolia Assam different types ()I Assam lemon(Citrus(Christrn,) Swingle and (iv) Citrus grandis (L.) Jimor1} and pummelo (CitlVsgral1di.~ are usuillivOsbeck, the remaining species grow in the found. Citrus aurantlUm grows almost under .submontane tracts (Bhattacharya and Durta, semi wild condition In Assam Citrus mediI,}1951), The concentration of the various grows commonly throughout North Eastelllspecies are location specific. The population states, both in alluvium soils and in the forestsof Citros ichangensis,· Citrus megaloxycarpa is valued for the sweet ;inc;! of the fnllL whIchand Citrus Jimonia is very limited and confined is usually eaten raw. Citron has been reportedto certain pockets, Citrus indica. which is to be growing in wild to semi wild condition inconsidered as the most primitive and probable Garo hills, Sikkim. Khasi hills and NC hills. ,iprogenitor of the Citrus species, was first Assam. The lemon (Citrus bmon) which isrecognized by Tanaka way back in 1928, who valued for· fragrance and acidic content of thefurther reported that, it is a really wild Citrus fruit hasa wide adaptability for soil and climah:found in Nowgong district of Assam, Khasi hills and is growing throughout North East upto anof Meghalaya and Manipur (Tanaka. 1937). It elevation of. 1700 m. Ghosh (1978) describedis also found in Nokrek hill range of Garo hills. KhasiMandarin, as a high quality mandarinNaga Hills near Dimapur and few pockets at orange covering largest area in the region.Mizoram. Much concentration of wild habitat Assam lemon, a citrOn type developed fromof Citros jambhiri is found around Shimmong, chance seedling, also covers considerable areaPugging, Ramshing and Gossang village in of sub-montane tracts and valleys of the region.Yinkiong district, along the course of Siang Ten distinct varieties of lemon have beenriver in Arunachal Pradesh (Hore, 1999), delimited in Assam showing the richness ofMaximum occurrence of diversity in the species . the materials. Citrusjambhiri is found to occurCitrus reticuJata, citrus Jimonia and Citrus in this region in many distinct forms in a semigrandis was found in the western parts of wild condition. The fruits are not valued in tradeAizawl district and Jampui hills area of North due to the warty character of the rmd andTripura bordering Mizoram (Hore etal.;·1997), extreme sourness of the fruits. The lime (CitnlsCitrus megaJoxycarpa, a rare species, was aurantilolia) is riot widely cultvated in the

Tab

le2.

Cit

rus

spec

ies

ofN

orth

Eas

tIn

dia

,j:> ~ ~ ~ ~ " $ ~

Dec

.to

Mar

.an

dN

ov.

toFe

b.O

ct.

toFe

b.

Oct

.to

Feb.

Nov

.to

Jan.

Nov

.-

Dec

.

Nov

.-

Jan.

Sep

t.to

Nov

.

Nov

.-J

an.

Dec

.to

Jari.

Oct

.-D

ec.•

Nov

.-D

ec.

Aug

.to

Oct

.S

ept.

toD

ec.

Apr

ilto

May

June

toO

ct

Sept

.to

Dec~

Frui

ting

seas

on

Sept

.to

Dec

.

Foo

thi

llsof

Him

alay

as,

Sikk

im,

Meg

hala

ya,

Ass

am,

Nag

alan

d,M

anio

ur.

Miz

oram

,A

runa

chal

Pra

desh

Ass

am,

Aru

nach

alP

rade

sh,

Nag

alan

d,M

egha

laya

Miz

oram

,M

egha

laya

,N

agal

and

Low

erA

ssam

&B

arak

Val

ley

Hill

sof

Ass

am,

Miz

oram

,A

runa

chal

Pra

desh

HiU

sof

Ass

am,

Meg

hala

ya,

Miz

oram

,T

ripu

ra,

Nag

alan

dan

dA

runa

chal

Pra

desh

So

me

pock

ets

ofA

ssam

,N

agal

and,

Man

ipur

and

Meg

hala

ya(G

aro

hills

),M

izor

amA

ssam

,M

izor

am,

Nag

alan

d,M

egha

laya

and

Aru

nach

alP

rade

shA

ssam

,M

egha

laya

,N

agal

and,

Aru

nach

alP

rade

sh

Ass

am,

Aru

nach

alP

rade

sh,

Nag

alan

d,M

izor

am,

Meg

hala

ya.

Man

ipur

and

Tri

pura

Ass

am,

Tri

pura

Loc

alna

me

Dis

trib

utio

nin

NE

stat

es

Soh

-myn

dong

(Kh.

),K

ata

Jam

ir(A

ss.),

Ass

am,

Aru

nach

alP

rade

sh,

Soh

-Jha

lia

(Kh.

),S

indh

uri-

netm

iten

ga(A

ss.;

Meg

hala

ya,

Man

ipur

Nem

u-T

enga

(Ass

.),M

ith-T

ulia

(Ass

.)B

ira

Jora

(Ben

g.l,

Soh

-Man

ong

(Kh.

),M

itha

Jor~

(Ass

.)

Kam

aJa

mir

(Ass

.),G

andh

a-H

anta

ra(A

ss.)

Dow

adi

(Ass

.),N

owgo

ng(A

ss.),

Jorh

at(A

ss.),

Kha

napa

ra(A

ss.),

Kam

rup

(Ass

.),K

hast

(Ass

.),B

urni

(Ass

.),Z

emab

awa

(Miz

o),

Aiz

wal

(Miz

o)B

orte

nga

(Ass

.),H

ukm

ate

nga

(Ass

.),H

aflo

ngte

nga

(Ass

.),Ja

mir

teng

a(A

ss.)

Ada

Jam

ir(B

eng.

)

Soh

-nia

ngri

ang

(Kh.

),S

oh-b

itar

a(K

h.)

Pat

ile

bu(B

eng.

,A

ss.),

Ass

amle

mon

(Ass

.),

Nay

a-ch

angn

ey(N

agaJ

,Gcx

iha-

pati

(Ass

.),K

ata-

jam

uri(

Ass

.),

Jora

-ten

ga(A

ss.),

Ela

chi

lebu

(Ass

.),S

oh

Uo

ng

(Kh.

),P

ani-

Jam

ir(B

eng.

),S

oh-S

ynte

ng(K

h.)

Soh

-sar

kar

(Kh.

)A

bhya

puri

lime

(Ben

g.),

Kar

imgu

njli

me

(Ben

g.)

Mit

haK

agzi

(Ass

.)S

oh-n

iam

tra

(Kh.

),S

oh-u

mkh

udai

(Rh.

),S

oh-s

yiem

(Kh.

),N

aga

San

tara

(Nag

a),

Nar

engi

(Hin

di)

Mim

ang

Nar

ang

(Gar

o)

Sp

ecie

s·

Citr

usja

mbh

iriL

ush.

Citr

usm

edic

aL.

Citr

usU

nion

(L.)

Bur

m.

Citr

usin

dica

Tan

aka

Citr

ussi

nens

is(L

.)O

sbec

k

Citr

usgr

andi

s(L

.)O

sbec

k

Citr

uska

ma

Rat

in.

Citr

usau

rant

ifolia

(Chr

istm

.)Sw

ingl

fC

itrus

Jim

etta

(Ris

so.)

Lus

h.C

itrus

.ret

icul

ata

Bla

nco.

Citr

usas

sam

ensi

sDut

ta&

Bha

ttac

hary

aB

arak

valle

yof

Ass

aman

dlo

wer

Jain

tia

hiU

sof

Meg

hala

yaS

atka

ra(B

eng.

),T

ithk

ara

(Ben

g.),

Soh

-kw

it(K

h.),

Ass

am(C

acha

r,K

arim

gunj

and

Cha

mar

baph

ang

(Man

i)K

arbi

Ang

long

).M

egha

laya

,M

anip

ur,

Tri

pura

Citr

usic

hang

ensi

s'Sw

iflg

leK

etsa

-shu

pfu

(Nag

a)N

agal

and

and

itsad

jace

nthi

llyar

eas

ofA

ssam

Citr

usIa

tipes

(Sw

ingl

e)T

anak

aS

oh-k

ymph

or-s

hrie

h(K

h.),

Soh

-shy

rkho

it(K

h.l

Meg

hala

ya(}

<has

ihi

Us)

,M

anip

urC

itrus

Iimon

iaO

sbec

k.R

angp

urli

me

(Ben

)N

ag

alan

d·

Citr

usm

acro

pter

aM

ontr

.

Citr

usm

egaJ

rJxy

carp

aLu

sh.

Citr

usau

rant

ium

L.

Kh.

-K

hasi

;A

ss.-

Ass

ames

e;B

eng.

-B

enga

li;

Nag

a-N

agm

ese;

Gar

o-G

aro;

Miz

o-M

izo;

Man

i.-M

anip

uri;

Hin

di-

Hin

di.

Vol. 25, No. 1,2004 5

region. The pummelo (Citrus grandiSj isconsidered to be an introduction to the·region.Barua et a1. (2001), reported the occurrenceof variabilityin Citrusgrandisin the South andWestern Garo hills of Meghalaya. Th~mandarin (Citrus reticulat~ is best-suited typefor North Eastern region. It is found to begrowing in semi-domesticated condition inSikkim, Khasi hills,. Garo hills and Manipur ofthe region (Bhattacharya and Dutta, 1951).

MAJOR CITRUS SPECIES OFHORTICULTURAL IMPORTANCE INNORTH EASTERN INDIA

The important species of Citrusof theregion, which are discussed below is necessaryWith a view to their respective classification,morphology and important-role in cUltivation.These are having commercial, propagative andresistant value against biotic and abioticstresses. The major Citrus species along Withtheir distribution has been given in Table 2..

MANDARIN GROUPCitrus reticulata: A highly

polyembryonic species originatedin Philippinesand extended to Cochinchina, having mediumsized upright trees, leaves lanceolate in shape

. With narrowly winged petiole. Fruits mediumsized,globose, sweet in taste, segments easilyseparable, core open at maturity, loose skinned,orange in colour, rind thin, usually 10-14segments in each fruit; seeds pointed with lightgreen cotyledons. .

ORANGE GROUPCitrus sinensis. Highly polyembryoniC

species of Chinese origin. Trees medium tolarge with blunt to pointed leaf apex andnarrowly winged petiole. Fruits subglobose tooval in shape, orange coloured, tight skinnedwith solid central core. Fruit light orange orreddish in colour, with smooth peel, pulp juicyand sweet. Resh colour usually lorange. Seedswith whitish cotyledons. This species has arootstock value to a limited extent.

Citrus aurantium: Highlypolyembryonic and cold resistant species. Treemedium in size, upright with dark green anddistinctively scented leaves. Flowers large andvery fragrant. Fruit medium sized, orange redcoloured skin. Flesh orange coloured, bitteracidic in tast~, rind separates easily. Highlyseeded, seeds flattened, cotyledons white. Thespecies was primarily used as one of theprincipal rootstock and flowers used forperfumery purpose. Susceptible to tristezavirus: Resistance to stress conditions of soil andclimate.

PUMMELO - GRAPEFRUIT GROUPCitrus grandis Syn. (Citrus maxima):

A monoembryonic species with large sizedfruits. Spreading, round topped, almost thornless tree. Leaves large with broad wingedpetiole. Lower surface of leaf is pubescent.Rowers very large, crowded in short axillaryracemes. Fruits large sized, subglobose topyriform in shape, with thick, spongy rind,smooth, large oil glands on rind. Seeds verylarge, coarsely veined and·white within.

ACID.GROUP. .' Citrus limon: A weekly polyembryonic

species with medium sized spreading trees.Leaves not dark green and leaf margins aresubs~rrated. Petioles medium sized andnarrowly winged.' Flower buds pigmented andpistil is densely dotted with oil glands. Fruitsoval to elliptic with pointed nipple. Fruit surfacesmooth, light yellow and core solid, juiceabundant and acidic. Seed cotyledons arewhite. Yields lemon oil, which is one of themost important oils used for flavouringpurposes in soft drinks, baked foods,confectioneries etc. Wide adaptability forvarious types of soil and climates: especially towater logging condition, resistant to scab,canker and'gummosis.

Citrus jambhiri: A highlypolyembryonic species. Tree medium to largeand spreading in growth habit. Leaves light

6 AGRICULTIJRAL REVIEWS

green, margins are not sharply serrated. Fruit angular when young, with stout sharp spines.rounded to subglobose with cavity or Leaves·narrow. Petioles very large, broadlydepre~ions surrounding the apical·papilla'or winged, obovate or oblong spathuIate. Fruitmpple. Medium to high acidic fruit. Fruit skin srnall glabrous, peel rough, seeds large sized.usually rough with brown colour, flesh yellow, High cold resistance.f.ore op(!n at.maturity, seed ~umer?us, small, " Citrus 'latipes: Thorny tree. Leavescotyledons I~ght gre~n. It IS an I~port~nt apex subacute or evenly bluntly rounded. Fruitsrootstock, SUIted to ~de r~ge of s~tls. Fa~rly borne in <single. Seeds usually bigger in sizetolerant to many CitruS diseases, IncludIng arid numerous. Fruits are too sman fortristeza. Drought resistant. commercial use. Tree hardy, resistant to cold

Citrus a4rantifolia: Highly temperature. High cold resistance, resistant topol~mbryonicspecieS. Small tree, bushy with greening disease.s~arp spi~es. Leaves small ~ith t1arrowl~ Citrusmacroptera: TaU tree. PetiolesWInged pet1ples. Rowers and .frutts. small. Fruit broadly winged. ~aves elongated, acuminate.rounded, to oval, mat~r1ng trre~ular~y Fruits with' 10-'12 segments, p\.lbescent;th~oughout the y~ar, greems?-yellow WIth~n segments I, - 2 seeded with scanty pulp,:,kinned. Cor~ ~ohda~ r:natunty, flesh greemsh depressed, almost without juice. Fruit flavoursm colour and Ju~~e aCld~c. ~eed small, s~ooth .. like ca.rdamom. Resistance to greening,Cotyledons whItish. It IS'hlghly susceptible to tolerant topsorosis and exocortis virus.tristeza virus and bacterial canker diseases. E

, OTHER MINOR CITRUS SPECIES OFTHCitrus medica: A monoembryonic REGION

sPoecies. Tree mediu~ sized, newgro~h Citrus jndica: Plant bushy, mediumpIgmented. Lea.f margIn serrat~. Leaf sIze sized, grows well in moist and shady areas.large a?d rumpled. Row~r large Sized, lem~n Fruits inedible, small, with slimy juice of acidicyellow, m cO,lour at .matunty, oblong to oval m t t' d It'" c.;,eds everyh' ' I . F·t . as e an unp easan aroma. vt:: ars ape, In many cases sty e p~rslsts. rul semI big and cover the major portion pf fruit.smooth.to rough surfaced. Rmd thick to very R dd' h' I . h " R,' t t tthO k h d" d' I, t d e IS In co our w en npe.. eSis an 0IC, ar an In some cases ess swee an " d' "

ti P I 'd" ·th ty" S d greemng Isease.aroma c.' u p aCI IC WI scan JUIce. eemedium sized and white inside. Tree susceptible Citrusassamensis: Medium sized treesto frost. Adaptation to moisture stress and low with thick glossy leaves. Fruits medium sized,soil fertility. almost spherical and smooth surfaced. A

C 't' k ' A d t I distinctive species having crushed leaf aroma1 rus arna: mo era e y . '1' t . I t R' t t t

I 'b . '. f'd I d simi ar 0 gmger or euca yp us. eSls an 0po yem ryomc specIes 0 WI e y use "as h' h . f IIrootstock. Tree medium to large sized. Leaves very Ig ram a .large with serrulate margin and winged petiole. Citrus limonia: Tree usually Vigorous,Flowers large and pigmented. Fruits medium spreading. Comparatively few and smallsized, rind surface irregular and apical papilla thorns. Foliage full green and new shootwell developed, rind thick and acidic in taste, growth lightly purple tinted. Flowers small,moderately seeded, cotyledons white. The petal deeply purple tinged. Cold hardy species.'Soh- Sarkar' variety. of Meghalaya belongs to Tolerant to tristeza virus and soil salinity.

this species. Citrus limetta: Small to medium sizedPAPEDA GROUP tree. Fruit small, round or depressed, yellow

Citrus ichangensis: Spiny shrub, twigs and acidless at maturity. Fruits are the truncated

Vol. 25, No.1, 2004 7

ap~x, with a strongly depreSsed circular furrowin the center with a pron:linent fleshy papillaor nipple.

Citrus megaloxycarpa: The species isendangered one and confined to Jampui hillsof Tripura. The fruits are sour and bit biggerthan Citrus macropteta fruit.

NURSERY MANAGEMENT.Citrus trees are propagated either by

seed or vegetafiv'e means. Vegetativepropagation is preferred over other means asit ensures true to type plants, uniform quality,early bearing etc. T budding is "rylost favoredpropagation m.ethod in 'citrlis, but dueimportance should be given in the selection ofvirus free scion variety. Singh (2000) reported.that seedlings are being used for limes andmandarin orange in North Eastern Hill region.In case of lemons and sweet ljme, air layeringand even cutting are being employed for raisihQplants.

Selection of mother plants for seedand bud-wood is the most important criteriafor production of healthy planting material. Theproductivity, longevity, fruit quality and diseasefree quality depends on mother plants.Therefore, selection of mother -plants shouldbe made from authentic sources with knownpedigree in respect to health, vigour, regularbearing and high yield with good fruit quality.Bud wood should·always be ·t'aken from wellmatured wood of currenl-sehson growth or nexttolast growth.

Seeds for rootstocks should becollected from mature and healthy fruits, whichare borne on disease free mother plant. Thisis important because rootstock is going toimpart the characters like productivity; vigour,precocity, physico-chemical characters of fruits,longevity of tree, disease resistancecharacteristics etc. Seeds of most of the Citrusspp. are recalcitrant type and it has to be takencare of, following the storage protocol.

It is desirable to raise citrus nursery inlight, well drainE:d fertile soil,- free from soilbQr.ne pathogens and nematodes. Minimumheight of seed bed should be 10 cm with 1 mwidth, which will help in easy culturaloperations. In order to raise the healthyprimary nursery, plastic'tra~ of 60x40x12 cmsize IS ideal. Seeds are sown in sterilized soilmixturEdone part' fertile s.oil + two part sand)with a spacing 2.5'-3.5 cm in the row of 1.5to 10 cm between 'the rows. A bed of 3x3 msize with a height of 3-4 inch from groundlevel is' j)repared for raising secondary nursery.'Seedlings when 4-6 inch tall·having 8-10 leavesare' usually transplanted to secondary nursery.This practice is followed during the month ofJune-July. Budding should be done in the .month of March-April, and it was found idealfor Khasi mandarin. Bud union should be atheig};1t of 8-10 inch above the ground level toavoid the burial of the union and thereby avoidinfection.

Management of nursery plants againstthe pests arii diseases like leaf miner, leaf eatingcaterpillar; citrus psylla and aphids theapplication of, monocrotophos @ 0.5-1.0 mlor qui1J~lphos @ 1.0 ml and against mitesdieofol @ 1.5 w1/lit~rwater are reco.rp111~ded

for secon~ n\lrsery.

PRODUCTIONIndia Accounts for 4.69% of the total

citruS'prOdudiop (4.43 million tones) in theworld, occupyiQg in· 0:37 million -h,ectares. Inour countr~', citrus is grown' ~n variedagroclimatic conditions where mandarins,sweet or:at;l~es, lime, lemons, pummelo andgrape .f~t are important citrus fruits growncommercially. In India, Maharastra (73,115 haltops in ar~ under citrus cultivation, while TamilNadu holds the top sl9t in terms of productivityi.e., 17.6 tons/ha (Singh"2000). The rich soilconditions, wide raiIlfaU· range and existenceof different altitude from almost sea levels to1500 m above, place this part of India a unique

00

Tab

le3.

Citr

usbe

ltsof

Nor

thE

ast

Indi

a(B

ased

onN

EC

stat

istic

sof

1996

)

~ l:i i .r- ~ ~

34.9

(3.6

).5

.3(3

.8)

16

.6(2

.6)

44

.5(3

.5)

9.6 1.4

6.3

12.7

Tot

alar

eaP

rodu

ctio

n(O

OO

ha)

(OO

Oha

)

5.5

9.0

(1.6

)1

3.3

109.

1(8

.2)

2.2

9.0(

4.1)

7.1

48

.2(6

.8)

Maj

orbe

ltsS

tate

Man

ipur

Meg

hala

ya

Aru

nach

alP

rade

shA

ssam

Bas

ar-A

long

belt

ofW

est

Sia

ng,

Kho

nsa,

Dap

orijo

Tin

suki

a,N

CH

ills,

Kar

biA

nglo

ng,

Nag

aon,

Jorh

at,

Dib

ruga

rh,

Nor

thL

akhi

mpu

r,S

onap

ur,

Khe

tri

and

adjo

inin

gar

eas

toM

egha

laya

Tar

neng

long

,T

ipai

muk

h,Ji

riba

m,

Par

bung

,T

insu

ngar

eaof

Chu

rach

andp

ur,

Tha

ngal

Kha

sian

dJa

inti

aH

ills-

Daw

ki,

Non

gjir

i,P

halg

an,

Lew

syie

m,

Pim

shut

ia,

Unw

jai,

Maw

long

,U

msn

ing,

Bur

niha

t,Sh

eila

,B

alat

,L

umsh

onog

,U

l'nili

ng,

Nay

abun

glow

,R

ongd

ong,

Sha

ngpu

ng,

Jow

ai,

Maw

synr

am,

Che

rrap

unje

eG

aro

Hill

s-R

anga

lpar

a,Sa

satg

iri,

Cha

ndig

ri,

Rin

gden

giri

,D

olon

giri

,D

inad

ubi,

Agu

arag

iri,

Miz

oram

Kol

asib

,T

aita

w,W

estA

izaw

l,T

hing

dwal

Nag

alan

dL

ongn

ok,

Mok

okch

ung,

Tue

nsan

g,W

okha

,K

hono

ma

Sikk

imS

ang,

Bhi

runa

,T

hauk

a,K

ham

dong

,M

azita

r,T

okel

,B

urm

iok

Tri

pura

Dha

rrna

naga

r,K

umar

ghat

,Ja

mpu

ihi

lls,

Am

onpo

i,V

hang

mon

(Fig

ures

inpa

rent

hesi

sin

dica

tepr

oduc

tivity

into

nsha

");

(Shy

amS

ingh

,20

00)

Vol. 25, No.1, 2004 9

position for the adaptation of almost all thecitrus species and varieties of commercialimportance. Despite being a natural home ofmany citrus species, hardly any of the NorthEastern state figures standing in the citrusproduction scenario in the country. Area and

'production of eight North Eastern states aregiven in Table 3. The low productivity of citrusin the region may be due to heavy and longspells (upto 6-7 months) of rainfall; heavy soilerosion due to cultivation upto 600 -700 slopes;plantation on seedlings; no use of amendmentsin acidic soils; wide spread zinc deficiency;rainfed cultivation; malnutrition of major andminor elements; no control against pests anddiseases and prevalence of viruses like Tristezaand Greening. Interference of weeds andlichens are also a factor.

The search for new rootstocks is acontinuous process for the improvement ofcitrus industry, as rootstocks have mostprominent effect on growth, productivity, fruitquality and longevity of the tree on one handand influence the susceptibility of ·the tree tovarious insects and diseases on the other. Inthis region, most of citrus plantations areseedling in origin. Bhattacharya and Dutta(1952), reported Kata Jamir (Citrusjambhir1)as a satisfactory rootstock for the Khasimandarin. However, it shows less intensity ofdieback symptom as compared to Mandarinseedlings, but it is not only susceptible to salinityof soil and root rot but also vulnerable tonematode infestation, which could be the mainreason for citrus decline (Agarwal, 1982). Dueto this reason only, it has been replaced by thetrifoliate orange and their hybrids.

The mandarin orange orchards of theentire North Eastern region are seedling inorigin. In the past some rootstock trials wereconducted at the Fruit Research Station,Burnihat, Meghalaya. Nandi etal (1943) triedrootstock species and the varieties like Citrusgrandis, Citrus jambhiri, Citrus aurantium,

Citrus macroptera and Citrus limon for KhasiMandarin scions and found that Citrus limonimparted better vegetative growth and ga~emaximum fruit yield. However, Sheo Govindet aJ. (1994), found that the Khasi mandarinscion budded on Rangpur lime rootstock gavemaximum'vigorous growth and yield followedby Citrus'volkameriane.

A brief characteristics of some of theimportant species of the region, which mayserve as suitable rootstock -

1. Rough lemon (Citrus jambhin):Trees of rough lemon turns out to be highyielder, but having poor fruit quality. It istolerant to tristeza and relatively tolerant tosaline and calcareous soils, but susceptible tofoot rot and blight.

2. Trifoliate orange (Poncirustri!oliata): It is a deciduous in nature and arelative of the genus citrus. It is susceptible to.exocortis and blight, but t01erant to root rotnematode. Trees on trifoliate orange gave highyield with excellent fruit quality, which is alsoresistant to frost.

3. Citranges (Citrus sinensis xPoncirus fri!oliatti): Some of the citrangevarieties like Troyer and Carrizo have becomeimportant rootstocks in the recent years. Theyhave wide range of soil adaptability, markedlyresistant to soil borne diseases and nematodesand tolerant to tristeza virus. This is a coldhardy, semi dwarfing rootstock and heighten~fruit quality slightly. It is highly susceptible toexocortis virus.

4. Rangpur lime (Citrus limonia): Avigorous rootstock with good adaptability towide range of soil, particularly for heavy soil.It is tolerant to tristeza virus and salinity of soil.However trees are susceptible to foot rot,exocortis and xyloporosis. Rangpur limerootstock is used for orange and grapefruit.

5. Mandarin (Citrus reticulata): Themost common mandarin rootstock is

10 AGRICULTURAL REVIEWS

C1eQptara. It is salt tolerant, tolerant to tristeza, pointed out the "citrus decline" as the majorexocortis and xyloporosis and fairly tolerant threat to the citrus cultivation in North Easternto Phytophthora root rot. states. According to Gupta (2000) once

6. Citrus taiwanica: It is a new flourishing citrus industry ofthe region startedrootstock introduced from Taiwan. It has been declining and received a severe jolt due to thisfound to be tolerant to gummosis and malady. Scientists from Assam Agriculturalmoderately salt tolerant. University, Jorhaf summarized the following

" factors, which are responsible for decline inKhasl Mandann, a much popular citrus orchards in the region ­

variety, is cultivated on commercial scale invalleys, submontane areas and in low hills of (i) Faulty site selection for orchards;North Eastern region.'Assam lemon c1Iso covers (ii) .Hig~ underground water ~evel; (iii) III .drainedconsiderable area of'submontane tracts. The SOIls; (IV) Improper plantmg mater)als; (v)entire mandarin orange orchards ,in the region Inadequate ..nutrition; (vi) Excessive ~hade .~~are primarily of seedling origin. Growers are orchards; (VII) Poor managemen~ practices; (V111)still lacking with the knowledge of using suitable Damage caused by pests and diseases.rootstocks. Soils of the plains are alluvial types, Growing of undesirable intercrops iswhile in the hilly areas it is mostly lateritic. also a matter of concern (Upadhyaya, 2000;Citrustree grow better in soils having pH range Yadav, 2000). Unsuitable intercrops may cause5.5 to 6.5. Major citrus growing belts of the serious root injury, particulariy to feeder andregion are situated in sandy loam soils with fibrous roots. In Khasi and Jain,tia hillspH ranging from 4.5 to 6.0. The orchards are intercrops like arecanut, jackfruit, banana etc.situated on the unterraced hill slopes and are grown as intercrops, resulting into lankypractically no soil conservation measures have growth of mandarin trees with very poorbeen adopted in such orchards, leading to canopy development. Undesirable intercropswashing of the rich surface soils by heavy like maize, ragi, buckwheat, ginger, etc. areerosive rains. Depending upon the slope, being grown in the orange orchards of Sikkim,rainfall intensity and soil properties, measures while certain growers of Jaintia hills growlike bunding, terracing, plugging and turmeric very closely in the bearing orchards;strengthening of slides of gullies etc, should be Orchards can be intercroppecl with ri;ldish,adoptea. cauliflower, cabbage, carrot, tomato, peas,CITRUS DECLINE fodder crops, cowpea, rice bean, soybean,

After 5 to 6 years of excellent growth, ladies finger et~. sUit~bly, which wo~ld notCitrus plants usually start declining with gradual exh~~st th~ sot! nutnents but provI.de ~hedecrease in vigour and yield. Declined trees do addlttona! mcome to g~ower9 FrUits l~kenot usually die but remain impoverished and . papaya, pmeapple can be mtercropped dunngunproductive. The symptoms comprised of the initial years of orchard establishment.retarded growth of trees, appearQnce' of The growers generally do not followchloratic leaves, sparse foliage, dieback of twigs proper spacing requirements; moreover,and in general, a sickly appearance of the tree manure and fertilizer application is also limited(Shivankar, 2000). In North Eastern region. to those orchards. Plant protection measuresthe prevailing high rainfall and humidity against major pests and diseases areprovides a congenial condition formost of the inadequate. As a matter of fact, due topests and diseases to grow multiply and attack ignorance, difficulties in the cultivation in hillycitrus for a longer period. Ghosh (1978) terrain. coupled with poor mrtrketing facilities,

Com

mon

nam

e

(1)

Tab

le4.

Impo

rtan

tpe

sts

and

dise

ases

ofth

ere

gion

,th

eir

sym

ptom

san

dm

anag

emen

t

Scie

ntifi

cna

me

Sympt~

and

natu

reof

dam

age

Man

agem

ent

~~

~

Pest

s

(i)Ps

ylla

(ill

Citr

usle

afm

iner

(iii)

Citr

usbl

ackf

Iy

(iv)C

itrus

whi

tefly

(v)L

emon

butte

rfly

(vi)

Citr

usap

hids

(vii)

Citr

usth

rips

(viii

)Mea

lybu

g

(ix)

Scal

es

(x)

Bar

kea

ting·

cate

rpill

ar

Dia

phor

ina

citr

i,K

uway

ama,

Psyi

lidae

:Hom

opte

raP

hyU

ocni

stis

citr

ella

Stai

nton

,Ph

yllo

cnis

tidae

:L

epid

opte

raA

leur

ocan

thus

wog

lum

iA

shby

,A

leur

odid

ae:H

omop

tera

Dia

leur

odes

dtri

Ash

ns,

Ale

yrod

idae

:Hom

opte

raP

apili

ode

mol

eus

L.,

Papi

lioni

dae:

Lep

idop

tera

Toxo

pter

asp

p.,

Aph

idid

ae:H

omop

t€T

a

Scir

toth

rips

spp.

Bou

che,

Thr

ipid

ae:T

hysa

nopt

era

Pla

noco

cc-u

sci

triR

isso

,Ps

eudo

cocc

idae

:H

oroo

pter

a

Aon

idie

Ua

aura

ntii.

Coc

cus

hesp

erid

us.

Icer

yapu

rcha

si,

Coc

eida

e:H

omop

tera

Inde

rbel

asp

p.,

Mel

arbe

lidae

:L

epid

opte

ra

Ora

nge

yello

wny

mph

ssu

ckce

llsa

pfr

omne

wgr

owth

and

flow

erin

the

mon

thof

Mar

ch-A

pril

and

Jultj

"Aug

ust

Lar

vae

mak

ezi

gzag

-min

eson

'leav

es.

The

infe

sted

leav

estu

rnye

llow

,tw

ist

and

final

lydr

y

Nym

phs

and

adul

tssu

ckce

llsa

pin

the

mon

thof

Mar

ch-M

ayan

dJu

ly-A

ugus

tand

excr

ete

hone

ydew

onw

hich

soo

tym

ould

grow

sle

adin

gto

man

ifes

tatio

nof

blac

kla

yers

Lar

vae

feed

onle

aves

from

mar

gin

inw

ards

and

the

dam

age

isse

vere

innu

rser

ies

Adu

ltsan

dny

mph

ssu

ck.t

hesa

pfr

omte

nder

leav

esan

dsh

oots

re5!

J\tin

gin

devi

taiis

atiO

nof

the

plan

ts.

Aff

ecte

dle

aves

inse

vere

case

scu

rlup

and

get

defo

rmed

.C

itrus

trist

eza

viru

sis

tran

smitt

edby

vario

usap

hids

spec

ies

Nym

phs

and

adul

tsra

span

dsu

cksa

pfr

omfu

llyde

velo

ped

flow

ers.

leaf

buds

,lea

ves

and

also

the

.yo

ung

and

grow

nup

frui

ts.

Lea

ves

beco

me

cup

shap

edan

dle

athe

ry.

Itis

econ

omic

ally

impo

rtan

tpes

tsof

Kha

siM

anda

rinin

Meg

haJa

ya.N

ymph

san

dfe

mal

esus

ually

feed

unde

rsid

eof

the

leav

esca

usin

ghe

avy

dam

age

tonu

rser

yan

dgr

ownu

ppl

ants

and

also

atta

ckth

eba

seof

frui

tsne

arth

est

ock

end

resu

lting

heav

yfr

uitd

rop

Nyt

nphs

and

adul

tssu

cksa

pfr

omfo

liage

/twig

,br

anch

esan

dst

ems

and

devi

taliz

eth

epl

ants

,re

sulti

ngin

yello

win

gan

dea

rlysh

eddi

ngof

thei

r_l

eave

s,be

arkJw

qual

ityfr

uits

with

less

erl1

umbe

rSe

riou

spe

stof

Meg

hala

ya,M

izor

am,A

runa

chal

Prad

esh.

Gru

bfe

edon

bark

port

ion

and

mak

esho

les

inst

ems

for

hidi

ng.G

row

thof

tree

isar

rest

ed

Spi!J

Ym

onoc

roto

phos

36W

SC(0

.036

%)

durin

gth

epe

riod

whe

nne

wflu

shap

pear

s.C

occi

nelli

dpr

edat

Ors

area

lsofo

un:!

tobe

effe

ctiv

eag

ains

tnym

phs

Spra

ym

onoc

roti>

phos

36W

SC(0

.036

%)

durin

gM

arch

-Aug

ust.·

The

larv

alpr

edat

orbl

ack

chaI

cid

and

the

chry

sopi

dho

ldgo

odpr

omis

efo

rits

cont

rol

Syst

emic

inse

ctic

ides

like

mon

ocro

toph

os0.

06%

are

effe

ctiv

e

Spra

yw

ithen

dosu

ifan

35

EC(0

.05%

)or

mon

ocro

toph

os(0

.036

%)

whe

nth

eat

tack

appe

ars

Folia

rapp

licat

lono

f0.

02%

met

hyld

emet

on,

mon

ocro

toph

osat

wee

kin

terv

alco

ntro

lspe

sts

effe

ctiv

ely.

Coc

cine

ilids

are

one

ofth

em

ajor

pred

ator

ofap

hids

Soil

appl

icat

ion

ofaI

dica

rb@

0.6

g/l

0lit

erat

6w

eeks

inte

rval

.

Prun

ing

ofaf

fect

edsh

oots

inw

inte

ris

effe

ctiv

e.Sp

rayi

ngif

dim

etho

atE!

150

ml

+ke

rose

neoi

l250

mIi

n10

0lit

erw

ater

chec

ksm

ealy

bug

Spra

yof

met

hylp

arat

hion

(Q.0

5%)

ornu

van

(0.0

1%)

also

give

ssa

tisfa

ctor

yre

sults

Rem

ove

web

bing

.and

trea

tthe

mai

r:i.li

mbs

and

trun

kw

ithm

ethy

lpar

athi

on50

EC(0

.1%

)in

Feb-

Mar

(Con

td.

~ :- ~ 9' z 9 .... ~ § .... ....

......

(1)

(2)

(3)

(4)

!\:)

{xi)

Tru

nkan

dM

on

oh

am

mu

sve

rste

egi

Mos

tim

port

ant

pe

stof

man

dari

nsin

NE

Hre

gion

.C

olle

ctin

gan

dki

lling

ofad

ults

ison

eof

the

cont

rol

Ste

mB

orer

Rit

sem

a,C

eram

bici

dae

:T

he

grub

bore

sin

toth

etr

unk

nea

rth

etr

eeba

sem

easu

res.

Tre

atth

eso

il6-

8cm

deep

arou

ndth

etr

ees

Col

eopt

era

and

mak

estu

nnel

sne

arth

epi

thw

ith

5%al

drin

toch

eck

the

atta

ck(x

ii)M

ite

Eut

etra

nych

usor

ient

a/is

Ext

ract

sce

llsa

pfr

omle

aves

and

frui

tsan

dF

olia

rsp

ray

ofdi

cofo

l@

1.5

ml,

mon

ocro

toph

osK

lien,

Tet

rany

chid

ae:

caus

esdr

yne

crot

icar

eas

1m

lw

hen

inci

denc

eno

tice

dre

duce

sth

ein

fest

atio

nA

cari

na(x

iii)

Nem

atod

eTy

lenc

hulu

sIn

fect

edtr

ees

are

no

tki

lled

but

grow

than

dbe

arin

gD

ichl

orof

enth

ion

@4

5m

llh

aef

fect

ive

tore

duce

sem

ipen

etra

nsis

adve

rsel

yaf

fect

edne

mat

ode

popu

lati

onD

isea

ses

(i)F

oot

and

roo

tP

hyto

phth

ora

spp.

Cau

ses

sym

ptom

sof

decl

ine

thro

ugh

rott

ing

ofth

eR

aisi

ngof

nurs

ery

inP

hyto

phth

ora

free

cond

itio

n.ro

t,cr

own

rot

root

lets

,gi

rdli

ngof

trun

ksan

ddr

oppi

ngof

blig

hted

Pai

ntin

gof

Bor

deau

xm

ixtu

reo

nth

etr

unk

upto

50

-an

dgu

mm

osis

leav

es.

Aye

llow

gum

mos

iszo

neat

the

cam

bium

60

cm.

Use

ofto

lera

ntro

otst

ocks

are

som

eof

the

appe

ars.

Bar

kcr

acks

,sh

reds

inle

ngth

wis

est

rips

cont

rol

mea

sure

s(ii

)D

ryro

otro

tF

usar

ium

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Vol. 25, No.1, 2004 13

the cultivators are reluctant to take care of their They confirmed the presence of greeningorange orchards and content with the disease in these area. The tristeza infected treeh~rvested fruits as nature's gift. leaves develop vanousdeficiencysymptorns like

Ghosh (1978) reported that, general leaf falling, root decay, twig Qieback, honeyneglect, mixed planting and undesirable combing etc. Use of tolerant rootstocks andintercropping, improper spacing, vigorous virus free bud wood checks the disease.weed growth, inadequate nutrition, (Zn and Ca Controlling of the viral vector is also anotherin particular), infection of Phytophthora root effective control measure. The greening diseaserot, gummosis, powdery mildew, canker; scab is caused by the MLO's and the infected plantsdiseases and infestation of insects and pests shows chlorosis of leaves, thickening of leaflike borers, aphids, scales, mites, leaf miners .blade, shortening of twig internodes, off seasonare common in mandarin oranges, which leads blooming leaf shedding and dieback. Uprootingto severe Citrus decline in the region. and burning of the infected trees andROLE OF INSECTS/PESTS FOR CITRUS controlling the vector 'citrus psylla' are theDECLINE control measures. The scenario of citrUs disease

In North Eastt:!rn region 42 insects in North Eastern region is altogether differentspecies are found to have assumed major pests from rest of the country. Besides soil bornestatus in the Citrus cultivation aggravating the diseases, those are wide spread, the attack ofcitrus decline problem. The increase in the foliar diseases is maximum in this area. Thisinsects incidence may be attributed to the regular monitoring of diseases in nurseries anddeforestation and continued new flushes in the orchards become mandatory in this region.region, which occurs from Feb _Mar extending Disease free plant materials, quarantine andupto April dUring some years followed by June sanitary measures, g'ood drainage and aeration_July and Sept _Oct (minor flushes). According of soil resistant. and compatible rootstocks areto Shivankar (2000), the insect pest problem some of the areas where emphasis needed tc.is due to the following reasons _ be entrust upon. Use of biocontrol agents with

low doses of chemicals coupled with host(i) Absence of plant protection resistance and improved cultural practices

measures; (ii) Heavy incessant rainfall; (iii) would be. the long term solution inScattered orchards; (iv) General neglect; (v) management of citrus diseases. Citrus cankerUneven topography. is also a wide spread disease in acid lime caused

Some of the major pests and 'diseases, by a gram negative bacteria lXanthomonasdinin Citrusand their symptoms and management (Hasse) Dowson}. The canker lesions appearpractices are given in Table 4. as minute water soaked roundish spots, which

Diseases like tristeza, greening and enlarge slightly and turn brownish and corky.canker causing havoc to the citrus cultivation Pruning and burning of diseased twigs, sprayingof the region. In 1966, Dr. Lilian Fraser,a of 1% Bordeaux mixture to emerging flushescitrus virologist from Australia also confirmed or application of streptomycin sulphate (500the presence of these diseases in the region ppm) are recoI'l1Ill€nded for control of the(Ghosh, 1985; Ghosh el aI., 1980) after disease.indexing large number of trees of mandarin HARVESTING, POST HARVESTorange and other citrus species growing in the MANAGEMENT AND MARKETINGmajor citrus belts of states like Meghalaya, The oranges produced in theArunachal Pradesh, Nagaland and Tripura. surrounding areas of Mawsynram, Cherrapunji

14 AGRICULTURAL REVIEWS

The Nokrek biosphere reserve inMeghalaya, earlier which was known as Citrusgene sanctuary in the region is a declaredreserve for Citrus indica species and itsvariabilities. Several Citrus species also growin buffer zone of the reserve. With persistenteffort of NBPGR Regional Station, Barapani,it was possible to' conserve the. area as genesanctuary for Citrusinmca (Bhag Singh, 1981).

In-vitro culture and to identify theviability and seed· storage behaviour, it wasfound that the seeds of Citrusjambhiri is highlyrecalcitrant type, while Citrus pseudolimonseeds are moderately recalcitrant. Rootstockof wild relatives i.e. Poncirus trifoliatais suitablefor grafting but the seeds are highly recalcitrant.

Considering the importance of thevaluable citrus wealth of this region and forthe future use as raw material for scientific andindustrial purposes, the emphasis has been laidon the collection and maintenance of the citrusspecies since the inception of NBPGR RegionalStation. At present this station is maintainingseveral germplasm accessions of Citrus specieslike Citrus jambhiri; Citrus limetta; Citrusgrandis; Citrus reticulata; Citrus limon; Citrus

ROLE OF NBPGR REGIONAL STATION INCITRUS GERMPLASM COLLECTION ANDCONSERVATION

The need to collect and conserve thegenetic resourc~s of Citrus has got paramount

and Sheila area of Meghalaya matures in 9-12 importance because the number of cultivatedmonths and have excellent quality with high genotypes are gradually narrowed down. Thecor.1mercial value and fetches good price in best available genotypes are being utilized withthe market. The oranges of Jampui hills range regards to their productivity and quality. Thereof Tripura is reported to have great demand in is also a· need to protect the collectedKolkata market. All these citrus taxa have many germplasm since many of the field genebankshorticultural importance and they have been are under deteriorated conditions due to severalused by the local tribal peoples for different factors.culi~a~ preparat~ons as .well as in the folk (:onsidering the significance ofmediCIne. The frult~ of Cj~S macropter~ ~re number of species and availability of varietal~eporte~ to be used In cooking and as medl?Ine . diversity as well as the possibilities to exploreIn certaIn areas of Megh~aya. and Man1p~ some more valuable types in inaccessible areas(Kaul, 19~1). The Sweet llI~e IS harvested In of. the region, there is need to build aSep~-~ov In Asscu:n and conSidered to possess comprehensive Citrus germplasm collectionmedl~Inal ~ropertles for ~he trea~ent of ~e~er throughsystematic survey. Such collections willand hver atlments. The nnd of citron and JUIce playa vital role towards conservation of speciesof sour lime is used for culinary preparations. and future research work.Fruits of sour lime (Citrus aurantium, are usedfor .making orange marmalades. The fruits ofassam lemon holds promise 'for extraction ofpectin, oil and citrate. The Govt. of Nagalandand Arunachal Pradesh in the region havestarted a modest extraction plant for processingof juice from Citrus reticulata. Similarly, theGovt. of Mizoram exploited Citrus macropteraas a raw material in industry for preparationof juice/squash. Despite of these,promisingemployment generating opportunities islacking. Production of value added productsare meager in the region due to lack of standardmaturity indices, nonavailability of degreening,precooling and mechanized handling units.There are no proper storage structures andduring seasonal glut, and thus the farmers areforced to sale off their produce at throwawayprice. Moreover the road networking to theorchards and main markets are very poor,hence transportation of the harvested materialis a serious problem.

Vol. 25, No.1, 2004 15

macroptera; Citrus sin(;!nsis; Citrus warrants in-depth study at cytological andmegaloxycarpa; Citros indica; Citrus medica; molecular level to ascertain their origin andCitrus kama; Citros aurantium; and an exotic identity. The local tribal peoples of the regionspecies Le. Citrus voIkameriana. Besides the have been using these species as medicine fortrue species and established varieties, many different ailinents since longtime, and theseintermediate forms were also collected during ethnobotanical uses are required for

, the course of germplasm collections, which documentation before it is lost forever.

/ REFERENCESAgarwal, PK (1982). Agric. Rev., 3: 17-34.Anonymous (1996). Basic Statistics of Northeastern Region. Northeastern Council, Shillong.Barua, U. et al (2001). IPGRINewsletter for Asia, The Pacific and Oceania, 36: 23.Bhattacharya, S.C; andDutta, S. (1949). C~ifjcation of Citrus Fruits of Assam. Directorate of Agriculture, Assam.Bhattacharya, S.C. and Dutta, S. (1951). IndianJ. Genet., 11: 57-62.Bhattacharya, S.C. and Dutta, S. (1952). Indian J. Hort., 9: 1-1l.Federov. (1974). Chromosome Numbers of Aowering Plants. Otto Koeltz Science Publisher, West Germany.Ghosh, S.P. (1978). Indian Hort., 23(2): 31-37.Ghosh, S.P. eta/. (1980). Punjab Hort. J., 20(3&4): 106-11l.Ghosh, S.P. (1985). Horticulture in North Eastern India. Associated Publishing Company, New Delhi.Gupta, S.G. (2000). In: Workshop on Citrus Decline and Management in NEH Region, held at ICAR Research

Complex for NEH Region, Umiam, 4-5 Sept, 2000, pp. 89-97.Hore, DK etal (1997). Pl Genet. Res. News/, FAO/lPGRI, Rome, 110: 57-59.Hare, DK (1999). Proc. Nat. Con! Sci. & Tech., pp. 101-106. Shillong.Kaul, G.L. (1981). Development of Horticulture in North Eastern Region - A Case Study of North Cachar Hills

District, NEC Secretariat, Shillong.. ' . .Kokaya, Ts.D. (1983). Trudy. Prikl. Bot. Genet. Selek., 78: 95-103.Nandi, HK et a/. (1943). Indian J. Agric. Sci., 13: 489 - 493.Sheo Govind etal (1994). Indian J. Hort., 5i: 123-129.Shivankar, v.J. (2000). In: Workshop on Citrus Decline and Management in NEH Region, held at ICAR Resca~ch'

Complex for NEH Region, Umiam, 4-5 Sept., 2000, pp. 61-75. .Singh, Shyam t2000). In: Workshop on Citrus Decline and Management in NEH Region, held at ICARResearch

Complex for NEH Region, Umiam, 4-5 Sept, 2000, pp. 1-26. .Singh, Bhag (1981). Establishment of First Gene Sanctuary in India for Citrus in Garo hills. Concept Publishing

Company, New Delhi" 15.Singh, J.P. (2000). In: Workshop on Citrus Decline and Management in NEH Region, held at ICAR Research Complex .

for NEH Region, Umiam, 4-5 Sept., 2000, pp. 35 -39. . .Singh, J.P. eta/. (2001). IndianJ. PI. Genet. Res., 14: 70-73.;Tanaka, T. (1937). J. Indian Bot. Soc., 16: 227-240.Upadhyaya, R.C. (2000). In: Workshop on Citrus Decline and Management in NEH Region, held at ICAR Research

Complex for NEH Region, Umiam, 4-5 Sept., 2000, pp. 27-34.Yadav, D.S. (2000). In: Workshop on Citrus Decline and Management in NEHRegion, held at ICAR Research

Complex for NEH Region, Umiam, 4-5 Sept., 2000, pp. 56-60.