“Advances in breeding of citrus ”   Advances breeding of Citrus, breeding of citrus, Advances breeding of Citrus by Gangaram Rana, polyploidy breeding of citrus, mutation breeding of citrus, biotechnology of citrus, gangaram rana

1. Speaker by
Gangaram Rana
Ph.D scholars .
Dept. Fruit Sciences
IGKV,RAIPUR

2. Citrus
• Botanical name : Citrus spp.
• Family : Rutaceae
• Chromosome no. : 18
• Type of fruit : Hesperidium
• Edible part : Juicy placental hairs
• Type of pollination : Self pollination
(Homogamy)
• Rate of Respiration : Non climacteric
• Type of bearing habit : Mix bearing

4. Commonly grown Citrus fruits
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Lime Lemon Sweet orange
Kinnow
Mandarin Citron

5. S.NO. SPECIES COMMON NAME CENTRE OF ORIGIN
1. C. medica L. Citron India
2. C. limon (L.) Burm. f. Lemon Eastern Himalaya
3. C.Aurantifolia(Christm.)
Swingle
Sour lime India
4. C. jambhiri Lush. Rough lemon Northeast India
5. C. reticulate Blanco Mandarin Cochin-China
6. C. sinensis (L.) Osbeck Sweet orange Southern Indo China
7. C. maxima (Burm.) Merr. Pummelo Polynesia and Malay
Centre of Origin

6. Centre of diversity
There are three major centers of diversity in
India
• North-East - Assam meghalaya,garohills, tripura
(citrus indica)
• South India - Gajanima, kichili, wild mandarin
• North-West region - HP, jammu &kashmir(hilly
areas) ;lemon (galgal)

7. Classification of Citrus
Acid group
• Acid lime : Citrus aurantifolia
• Tahiti or Persean lime: Citrus latifolia
• Rangpur lime: C. limonia
• Lemon: Citrus limon
• Rough lemon: C. jambhiri
• Citron: C. medica (Kidarankai in Tamil,
used for pickling)
• Sweet lime: Citrus limettoides
Rangapur lime
Rough lemon

8. Mandarin group: (loose jacket)
• Coorg mandarin, Nagpur Santra and Kodai orange: C.
reticulata
• Japanese Satsuma mandarin: C. unshiu
• Willow leaf mandarin: C. deliciosa
• King mandarin: C. nobilis
• Kinnow mandarin: King x willow leaf
• Tangerine orange var Dancy (Trifoliate x mandarins): Citrus
tangerina

9. Orange group:
• Sweet orange: Citrus sinensis
• Sour orange: Citrus aurantium
(Narthankaai in Tamil, used for pickling)
• Multiple leaf orange: C. multifolia
• Japanese summer grape fruit: C. natsudaidai
Pummelo and grape fruit group:
• Pummelo: C. grandis
• Grape fruit: C. paradisi
• Kumquat: Fortunella sp.
Grape fruit Pummelo

10. Criteria Lemon Lime
Botanical name Citrus limon Citrus aurantifolia
Origin Eastern Asia India
Stamens More (20-40) Less (20-25)
Fruits shape Oval to elliptical with pointed
nipple
Round to oval without
pointed nipple
Leaves Broadly winged Narrowly winged
Polyembryony Weak High
Cultivars Eureka, Pant Lemon, lisbon
etc.
Kagzi lime, Tahiti lime
Distinguishing characters of lemon and lime

11. Criteria Mandarins Sweet Orange
Botanical name Citrus reticulata Citrus sinensis
Origin Cochin-China Southern Indo China
Known as Fancy fruit or loose skinned orange Malta or tight skinned orange
Tree size Small (2-6) Tall (6-12)
Flowers Smaller than orange Relatively larger
Leaves Small and lanceolate Large with blunt pointed leaf apex
Fruits Globose and orange in colour Oblate to globose and light orange
reddish in colour
Seeds Less (10-15) More (15-20)
Fruit peel Easily removable Sticky and tedious to peel
Fruit core Hollow Solid
Cultivars Emperor, Kinnow ,Nagpur, Khasi
etc.
Mosambi, Blood Red, Valencia etc.
Distinguishing characters of Mandarins and Sweet Orange

12. Criteria Pummelo Grape fruit
Botanical name Citrus maxima /grandis Citrus paradisi
Origin Malaya South china
Tree Spiny, spreading and smaller than
Grape fruit(5-10)
Spreading and larger (10-15)
Flowers Larger with creamy petals Axillary, fragrant and with white
petals
Leaves Large, pubescent Large and glabrous
Bearing Single Clusters
Fruits Globose or pyriform Spherical or obovate
Segments Open at centre Closed
Fruit rind Thicker Thinner than Pummelo
Seeds Monoembryonic Polyembroyonic
Cultivars Walter, Chakaya etc. Ruby, Foster, Thompson etc.
Distinguishing characters of Pummelo and Grape fruit

13. Citrus group Cultivars
Sweet Orange (C. sinensis (L) Osb.)
(a) Common or round orange
Hamlin, Valencia, Netal, Pera, Shamouti (Jaffa), Pineapple, Mosambi, Delta,
Campbell, Frost.
(a) Navel oranges Washington Navel, Atwood, Fisher, Newhall, Navelina, Navelate, Summerfield,
Marrs, Bajaninha, Palmer, Cara Cara.
(a) Pigmented (blood) oranges Tarocco, Moro, Sanguinello, Melta Blood Red.
Mandarins
(a) Satsuma group (Citrus unshiu Marc)
(b) Common mandarin (Citrus reticulate
Blanco)
(c) Meciterranean'
'Willowleaf' mandarin (Citrus deliciosa
Tenore)
(a) Other mandarins
(i) Citrus nobilis
(ii) Citrustangerina
Grapefruit (Citrus paradise Macf.
(a) While- fleshed
(b) Red-fleshed
Satsuma, Owari,'Miyagoma' Wase, 'Okitsu' Wase (Wase= early maturing)
Clementine, Fina, Ponkan, Pongan, Nagrpur, Darjiling, Coorg, Khasi, Beauty,
Cleopatra, Fortune, Kara.
Willowleaf,
Kinnow,
Wilking, Avana.
King Temple
Dancy
Duncan, Marsh, Walters
Star Ruby, Foster, Hudson, Thompson, Redblush, Ruby Red, Flame
Limes (C. aurantifolia L.)
(a) Acid lime
(i) Tahiti
(ii) Key
(b) Acidless lime
Persian, Bearss
Mexican, Kagazi, Banaarsi, Sai Sarbati, Pramaline, Vikram, Jai Devj (PKM-1)
Tenali-1
Sweet lime, Persian Mitha
Lemons (C. limon Burm. F.) Femminello, Verna, Limoni, Blianchetti, Lisbon, eureka, Fino, Kagazi Kalan,
Nepali Oblong, Assam Lemon, Baramasi
Pummello (Shaddock (C. gradis(L) Osb.)
(a) Thai group
Chander (Pink Fleshed), Kao Panne and Kao Phuang (white fleshed).
Goliath, Mato, Shatinyu
Citrus species and their commercial cultivars (scions) used in breeding

14. Citrus germplasm being maintained at various field genebanks in India
Singh and Singh, 2003

15. Country Flowering time Fruit set Maturity
N. India March (Feb.-
April)
April-May Mandarin Feb.
Sweet orange
Nov.-Jan.
S. India Sathgudi orange Dec. April & Sept.-
Dec.
Mandasia March
April
Central
India
Coorg mandarin
Oranges
March-April &
Sept. Oct., June,
Oct. – Feb.
Sweet Orange
Aug.-Oct.
Lemon and lime throughout the year
Flowering, Fruit set and maturity of Citrus

16. lime (C. aurantifolia
)
Mandarin (Citrus reticulata)
Sweet orange
(Citrus sinensis)

17. Problems in citrus breeding
Time
Polyembryony
Sterility
Self incompatibility
Long juvenility

18. Time
Citrus being perennial in nature takes more time for bearing. However this period can
be reduced to a maximum of half by top working the seedling on an old tree.
Polyembryony
• It is peculiar feature found in citrus in which seed consist of more than one embryo.
Sterility
• High level of sterility often leads to production of seedless fruits which is serious
hindrance to develop varieties.

19. Self incompatibility
Self incompatibility and cross incompatibility is a common phenomenon which occurs
widely in citrus.
Most of the varieties of grape fruit (C.grandis) are found to be self incompatible besides,
some varieties of lemon, sweet orange and mandarins exhibit self incompatibility of
gametophytic type governed by oppositional alleles.
Long juvenility
It is a major barrier in the progress of citrus breeding in India.
General treatments to shorten the period or induce early flowering have not been
generally effective.

20. Inheritance of characters in Citrus
Character Inheritance References
Leaf character Two principal genes Soost and Cameron,1975
Anthocyanin
pigment in leaf
Dominant gene controlling this
reddish colour.
Taxopene,1962
Anthocyanin
pigment in fruit
More than one recessive genes
are involved.
Spigel-Roy,1988
Tristeza virus Single allele Mestre et al.,1997
Texture Polygenic control Yamamoto et al.,1990
Polyembryony More than one single gene Maheshwari and
Rangaswamy, 1958
Seedless character A recessive gene Spigel-Roy,1982
Nucellar
embryony
One or two dominant gene Soost and Cameron,1975

21. Breeding Objectives
Fruit characteristics
 An excellent desert quality fruit
 Seedless varieties
 Suitable shape and size
 Meeting the commercial requirements, good shipping and
keeping qualities
 Attractive rind colour
 Firm texture and good flavor to meet the canning industry
requirements e.g. grapefruit, citron and oranges.
 High juice content for juice and mixed drink purposes and
high vitamin C content.

22. Tree performance Fruit characteristics Postharvest of fruit
High Yield Exterior appearance: size
and shape
Handling for fresh market
Low tendency to
alternate bearing
Economic and cultural
importance
Adaptation to adverse
climatic (Cold
Hardiness)
and soil conditions
Quality (TSS/ acid ratio),
Juice content, flavour/
colour
Processing quality (processed
into frozen concentrate or
single strength juice products)
Adaption to mechanical
harvest
Ease of peeling,
seedlessness
Storage life
Disease and pest
resistance
Season of ripening
(Enlargement of the
ripening season)
Juice content and composition
Scion characteristics

23. Rootstock characteristics:
• Improved productivity
• Dwarf stature
• Adaptation to soil conditions (salt, calcareous soils)
• Improvement in nutrition
• Resolution of bud union problems
• Resistance to diseases (Phytophthora, Tristeza, citrus blight,
Alternaria, Scab, Greening etc.)
• Resistance to soil borne pests
• Improved fruit quality

24. Rootstock Characteristics
Rough Lemon (C. Jambhiri Lush) Drought tolerant, imparts large vigour, deep root system,
poorly freeze-acclimated, tolerant to citrus tristeza virus
(CTV) and citrus exocortis viroid (CEV) and citrus
xyloporosis viroid,
Rangpur Lime (C.reticulate hybrid) Rsistant to CTV; but susceptible to CEV, burrowing
nematodes and moderately susceptible to foot rot; tolerant
to drought, imparts moderated vigour to scion, tolerant of
high saline and calcareous soil conditions.
Sour orange (C. aurantium L.) Imparts moderate vigoour to scion trees, deep and
moderately branched root system, moderately drought and
phytophthora tolerant, scion-trees on this stock-well
adapted to high pH and high salinity soils,
'Cleopatra' Mandarin
C. reticulate Blanco)
Produces a deep, densely branched root system that
imparts drought tolerance, also imparts cold tolerance,
adapted to wide range of soils from light sands to heavey
clays, resistant to high soil salinity.
Important Citrus rootstocks and their characteristics

25. Trifoliate orange
(P.trifoliata(L.) Raf.)
Rangpur lime:
Rough lemon
Carrizo citranges
Sour orange
Alemow (C.
macrophyllas):
Severaria buxifolia
Extremely freeze-hardy, deciduous and become dormant during winter
months, tolerant to CTV or xyloporosis but susceptible to blight, highly
resistant to foot-rot
It is salt resistant, tolerant to tristeza, xyloporosis, and moderate tolerance to
Phytophthora but susceptible to exocortis and greening.
Deep root system, resistant to tristeza, moderately tolerant to cold and salt,
but susceptible to Phytophthora, exocortis, greening and burrowing
nematodes.
Highly resistant to gummosis and tolerant to quick decline but sensitive to
salts.
Well adjusted to heavy wet type of soil partly due to its moderate resistance to
Phytophthora, highly resistant to exocortis and xyloporosis but susceptible to
triseza.
Used for lemons in USA tolerant to high levels of soil boron, chloride, and
calcium and tend to have high level of Mn, It is considered Phytophthora
resistant.
Cl and B excluder

26. Important Rootstocks
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Trifoliate orange Rough Lemon
Troyer Citrange Cleopatra mandarin
Rangpur lime

28. Introduction
• USA -Tangerines, St.Michael Blood Orange, Washington Navel, Valencia, Villafrance and
Large White Orange
• Grapefruits were introduced from California and Florida,
• lemons from China and
• Malta from USA and Italy.
• ‘Mosambi’ seems to have been introduced in Nagpur during the beginning of the 20th
century.
• The introduction of ‘Kinnow’ mandarin (King x Willow leaf) in 1947 showed great promise
in North India from USA.

29. Clonal selection
 Yuvaraj Blood Red’ is a seedless and early maturing clonal selection from
‘Blood Red’ orange.
 PKM 1 lime is a clonal selection from seedling progenies of kadayam Type of
Tirunelveli district of Tamil Nadu.
 Pramalini and Vikram, the two kagzi lime varieties were developed through
clonal selection at Marathwada University.
 Chakradhara’ is a thornless and seedless selection from Kagzi lime.
 Sai sarbati (rahuri , Maharashtra), Jaidevi (TN), Tenali (AP)
 LEMON : Pant lemon, baramasi, from PAU selection
ACID LIME

30. Hybridization
Citrus breeding involves selection and hybridization by controlled
crossing of two genetically distinct parents to obtain desired variety.
Scion Breeding/Cultivar breeding
• Selection of parents with high combining ability complementary and
heritability of desired characters.
• Zygotic seedlings are planted and evaluated
• Desired and best performing progenies are budded on commercial
rootstocks and evaluated.
• E.g. Kinnow mandarin- King x Willow leaf) (Honey, Sunburst, Fallago,
Rabinson

32. Intrageneric hybrids are:
• Tangor : C. reticulata x C. sinensis,
cultivars are temple, clamentine,
monreal, Umatilla, monoembryonic
• Tangelo: C. reticulata x C. paradise,
cultivars are Orlando, Sampson,
Seminole.
• Lemonima: C. limon x C. aurantifolia
• Lemmonnage: C. limon x C .reticulata

33. Hybrids Parental spp.
Citrange- Trifoliate orange x C. sinensis,
Citrange quat- Trifoliate orange x (kumquat)
Citrangedin (Ponicirus trifoliate x C. sinensis) x C. mitis
(calamondin)
Citrangor- Citrange x C. sinensis
Cicitrange- Citrange x ponicirus trifoliate
Citrandarin- P. trifoliate x C. reticulate (mandarin).
Citermon- P. sp x C. aurantium
Citumquat- P. sp x C. japonicum x F. margarita (kumquat)
Citrumelo- P. trifoliata x C. paradise (grape fruit).
Intergeneric hybrids

34. Hybrids Parental spp.
Limonage C. lemon x C. sinensis
Lemonimes C. limon x C. aurantifolia
Lemandarins
Tangelo
C. Limon x C. Reticulata
C. reticulata x C. paradisi
Tangors C. sinensis xc. reticulata
Interspecific hybrids

36. 5/17/2021 36

37. • Procimequat: F. japonicum x C.
aurantifolia (acid lime) x F. hindisi
• Limequat: C. reticukata x F.
japonicum x F. maragarita
• Orangequat C. reticulata cv.
Satsuma x F. japonica x F.
morgarita cv. Meiwa
Hybrids of Fortunella (kumquat) are

38. Mutation Breeding
• Somatic mutations are common in citrus and through selection of the
natural mutants, quite a few number of desirable clones have been
obtained.
• Selections of natural mutants have been successfully employed for
season of ripening (Satsuma, Navel), improvement of colour (Ray
Ruby grapefruit) etc. in Citrus.
• Grape fruit : ‘Star Ruby’ and ‘Rio Red’
• The grapefruit clones like Thompson and Foster Pink arise as limb
sports on white grapefruit.
• Gamma irradiation of seeds and bud woods performed in Orlando,
Florida, resulted in Seedless fruits on certain trees of seeded cultivars
like Pineapple orange as well as Duncan and Foster grapefruit.

39. Polyploidy breeding
• Most of the species and varieties of Citrus are diploids but
occurrence of polyploidy has been reported in many cultivars.
• The Hongkong wild kumquats,Fortunella hindsii may have been the
first reported tetraploid.
• Production of triploids by crossing tetraploid with diploids may be
useful in obtaining seedless varieties. The seedless lime (C.
latifolia) a triploid.
• Polyploidy manipulation by crossing of tetraploids with diploids
yielded some valuable triploid varieties like ‘Oroblanco’ and
‘Melogold’.

40. MICROPROPAGATION:
• SHOOT TIP/ AXILLARY BUD CULTURE: For multiplication of superior clones of
almost all cultivated species , hybrids , rootstocks.
• Utilized for propagating weak polyembryonic commercial cultivars.
• These are healthy , uniform , virus free , true to type plantlets.
Embryo rescue utilised in citrus:.
• In citrus, nucellar embryony is the major hinderance in getting only the embryo of
hybrid origin but in early stages of development, it is easy to get the embryo of
hybrid status, which is the major breeding priority.
• RFLP analysis of low and high-copy-number nuclear DNA can be used to
distinguish zygotic from nucellar in vitro seedlings.

41. SHOOT TIP GRAFTING: Has been standardized in mandarins and sweet orange
which produce true to type , virus free precocious planting material.
PROTOPLAST FUSION AND GENETIC TRANSFORMATION:
Development of triploid scions and rootstocks with resistance to biotic and abiotic
factors are other promising areas.
Genetic transformation studies and use of coat protein gene could produce tolerant
varieties to citrus decline.
SOMATIC HYBRIDIZATION
• The somatic hybridization potential has been exploited for rootstock and scion
improvement in citrus (Grosser and Gmitter 2005). Somatic fusion offers possiblity
for efficient creation of allotetraploid citrus plantshaving the highest level of
heterozygosity.

43. Ruby Red Grapefruit C. paradisi Star Ruby Grapefruit
Rio Red Grapefruit Henderson Grapefruit

44. Duncan Grapefruit
Foster Grapefruit
Hudson Grapefruit Marsh Grapefruit

45. New Zealand Grapefruit
Thompson Grapefruit

47. Hamlin Orange Marrs Orange
Valencia Orange Navel Orange

48. Jaffa Orange Pineapple Orange
Blood Orange ParsonBrown