“Advances in breeding of papaya”  new accepted in papaya breeding, technology use of papaya breeding

1. “Advances in breeding of Papaya”
Speaker by
Gangaram Rana
Ph.D scholars .
Dept. Fruit Sciences
IGKV,RAIPUR

2. BREEDING OF PAPAYA
Botanical name: Carica papaya L.
Family: Caricaceae
Chromosome number: 2n=2x=18
•Introduction
•Papaya is an ideal fruit crop for growing in kitchen garden, backyards of home
• Rich source of vitamin A (2020 IU), vitamin C (40-60mg/100g) carbohydrates and minerals.
Papaya is native to Tropical America ( Badillo,1971). The South America and Costa Rica are the micro
centre of origin of papaya.
 In India it was introduced in early part of the 16th century from Philippines through Malaysia.
 India is largest producer of papaya in world. It also cultivated in Brazil, Mexico, Australia, Hawai,
Malasia, Taiwan, Peru, Florida, South Africa and Bangla Desh.
 In India it is widely cultivated in Uttar Pradesh, Bihar, Karnataka, Jharkhand and Madhya Pradesh etc.
Centre of diversity

3. Floral biology and pollination
 Dioecious papaya produces male and female trees separately on different plants in the ratio
of 1:1, while gynodioecious cultivars produces both female and andromonoecious trees in the
ratio of 1:2. Female and male flowers develop within 32 and 42 days respectively after bud
initiation.
 The period from bud initiation to anthesis is shorter for male than female flower bud
(Dhaliwal et al., 1991).
Stamen development occurred prior to ovary development in the hermaphrodite flower and
stamen differentiation was observed 56-59 days before anthesis.
Anther dehiscence starts 18-36 hours before the flowers opening and continues depending
upon the weather conditions and stigma becomes receptive a day before the flower opening
and remaining receptive for 6 days.
The peak anthesis was observed between 5.00-6.00 a.m. The receptivity of stigma was found
maximum on the day of anthesis in most of the species (Subramanyam and Iyer, 1986).
the female and male ratio should be 20:1.

5. Flowers and fruits of male, female, and hermaphrodite papaya.
(A)Female flowers; (B) hermaphrodite flowers; (C) male flowers;
(D) female fruit; (E) hermaphrodite fruit; (F) male tree.

6. Germplasm resources
Category Bengaluru Coimbatore Pune
2017-18 Total 2017-18 Total 2017-18 Total
Collection Nil 36 - 89 Nil 10
Characterization - - - 80 - 10
Conservation 36 36 84 84 9 9
Evaluation - - 1 46 9 9
Utilization 4 5 - 8 - 5
Status of collection, characterization, conservation of papaya germplasm at different centre

7. Classification (Badillo, 2001).
S. No. Species and cultivar Specific features
1. V. candamarcensis resistant to virus
2. V. cauliflora resistant to virus
3. V. pennata resistant to frost
4. V. pentagona resistant to frost
5. V. pubescence resistant to PRS virus
6. V. candicans resistant to PRS virus
7. V. stipulata resistant to PRS virus
8. V. monoica monoecious, susceptible to virus

8. Genetic and inheritance of sex
Papaya is a polygamous plant with three basic sex forms –pistillate, hermaphrodite and
staminate, where pistillate ( female).
Based on sex forms and flower, storey (1958) classified papaya flowers to 8 type viz.
I. Staminate,
II. Teratological staminate,
III. Reduced elongate,
IV. Elongata,
V. Carpelloid elongate,
VI. Pentandria,
VII. Carpelloid pentandria, and
VIII. Pistillate.
Out of these, type (i) flower are produced by male plants, type (ii) be sex
reversing male plants, type (iii) to (vii) by hermaphrodite plant and type (viii) by
pistillate plants.

9. Genetics of important traits and their inheritance pattern
Sex Inheritance is controlled by 3 genes
M1 = dominant factor for maleness
M2 = dominant factor for hermaphrodites
m = recessive factor for femaleness
Genetic constitution
M1m = Staminate plant
M2m = Hermaphrodite plant
mm = Pistillate plant
Cross or self Female plant Hermaphrodit
e plant
Male plant Non - viable
mm x M1m 1 mm - 1 M1m -
mm x M2m 1mm 1 M2m - -
M2m x M2m 1mm 2 M2m - 1 M2M2
M1m x M1m 1mm - 2 M1m 1 M1M1
M2m x M1m 1mm 1 M2m 1 M1m 1 M2M1
Storey (1958)

10. Breeding objective of Papaya
To develop dwarf statured and early bearing varieties.
To evolve varieties with high yield and good quality fruits.
 To develop varieties with low cavity index and more pulp thickness.
 To breed varieties having good keeping quality and suitable for
export.
 Breeding for high latex yield with high proteolytic enzyme activity
 To develop varieties resistant to biotic and a biotic stresses (virus,
frost, water logging etc).

11. Breeding methods and achievements
Introduction
Variety Introduction
Soniyimma , Malinchly, Maru Ank LG Introduce from Nigeria
Sunrise , Wilder, Sunset, Kapohosolo, HCAR-16,
Sunrise HCAR-29, Maradol HCAR-19 and
California
Introduce from USA
(Singh and Rana, 1993).

12. •Inbreeding and selection
Varieties Breeding method Specific features
TNAU Varieties
CO-1 Selection from Ranchi type -
CO-2 Selection from Local type Suitable for papain extraction
CO-5 Inbred selection from Washington Suitable for papain extraction
CO-6 Inbred selection from Giant Dual purpose (both table and
latex- papain
IIHR Varieties
Coorg Honey Dew Selection from Honey Dew Gynodioecious
IARI Varieties
Pusa Giant Selection from Ranchi Dioecious , Suitable for canning,
Tolerant to strong wind
Pusa dwarf Selection from Ranchi Dioecious
Pusa Delicious Selection from Ranchi Gynodioecious type
Pusa Majesty Selection from Ranchi Gynodioecious type, tolerant to
virus
PAU Varieties
Punjab Sweet Selection frost tolerant and dioecious in

13. Varieties Parents Specific features
TNAU Varieties
CO -3 CO 2 x Sunrise Solo A tall vigorous plant, fruits
medium size, sweet, good
keeping quality
CO- 4 CO 1 x Washington Plant medium tall, fruits large,
flesh thick and yellow, good
keeping quality
CO -7 Coorg Honey Dew x CP 85 High yielding red fleshed,
uniform fruit shape,
gynodioceous with good edible
character, yield 98 fruits/tree
each weighing 1.15 kg.
IIHR Varieties
Arka Surya
Arka Prabhath
IIHR-54
Sunrise Solo X Pink Flesh Sweet
Surya X Tainung-1 X Local Dwarf
Waimanalo X Pink Fleshed Sweet
Gynodioecious
Hybridization
Important hybrids developed in India

14. Induction of polyploidy
Hofmeyer (1945) reported on polyploidy in papaya.
 They found that the quality of tetraploid fruit was better than the diploid and it was
also compact with small seed cavity.
But tetraploids were less fertile than diploid as indicated by comparative seed
count. However, according to Singh (1955) there was complete sterility in both
female and male tetraploids and expressed doubt about their commercial utilization.
Further, Zerpa (1957) reported that colchicine induced tetraploid hermaphrodite
plants, which were used as male parent in a cross with a female diploid produced a
few seeds without endosperm, by embryo culture, two triploid plants were obtained
which turned out to be hermaphrodite.

15. Heterosis breeding
Dai (1960) reported heterosis in the cross between Philippines x Solo varieties. F1
hybrid tended to have reduced seed number and enhanced plant vigour. Heterosis up
to111.4% for yield and yield traits was obtained in Solo yellow x Washington whereas
high heterosis for potential economic competitiveness was noticed in Thailand x
Washington (Iyer and Subramanyam, 1981).
At IIHR, Bangalore, an F1 hybrid namely, Surya (Sun Rise Solo x Pink Flesh
sweet) was released recently. It is gynodioecious in nature and produces about 75-80
fruits of medium size weighing about 600-800g. the flesh is red in colour, firm, sweet
to taste with a TSS of 14º brix.

16. Mutation breeding
Ram and Majumder (1981) developed a dwarf mutant line by treating papaya seed with
15K gamma rays. Initially, 3 dwarf plants were isolated from M2 population. Repeated
sibmating among the dwarf plants helped in establishing a homozygous dwarf line Pusa
Nanha.
Biotechnology
In-vitro propagation and genetic engineering technique can serve as a potential tool to
overcome major constraints in Carica papaya.
Embryo culture
In papaya, incompatibility is mainly due to the failure of endosperm formation. The
hybrid embryo resulting from interspecific cross of C.papaya and C.cauliflora has been
successfully rescued on White’s medium in 30 days by Yung (1986).

17. Transgenic papaya
•Transgenic papaya has been developed against Papaya Ring Spot Virus (PRSV)
using coat protein mediated resistance in University of Hawaii by Dennis
Gonsalves.
•Transformation with coat protein gene was done using micro projectile
bombardment technique using embryogenic tissues of papaya.
•Two transgenic lines Sun UP from Sun Set Solo and UH Rainbow from Kapoho
were developed which have shown excellent resistance to PRSV.
• Sun UP, which is homozygous for CP (Coat Protein gene), was resistant to most
isolate of PRSV, from other geographical locations except Taiwan’s YK isolate of
PRSV.
•Rainbow was found susceptible to PRSV isolates from outside Hawaii but was
resistant to the severe strain of Hawaiian PRSV (HA isolates).

18. • Two varieties Sun Up (from Sunset) and UH Rainbow (from Kapoho Solo) were found to be
resistant to PRSV.
Kapoho Solo(yellow flesh) × Sun Up(red flesh)
↓ ↓
Commercial PRSV (GE resistant)
/
Rainbow papaya
• Rainbow papaya is first variety of any fruit crop which is developed from GE at commercially
level in 1998. After 13 years feb 2011 it ready for compulsory labelling in Japan.
• PRSV are found all papaya groups and transmitted by aphid. The PRSV are two types-
• PRSVp--- found on papaya and cucurbits
• PRSVw--- it is not found on papaya found only on few cucurbites.

19. Future line of work
The future needs of varietal improvement in papaya are-
• Exploration, conservation and characterization of genetic variability.
• Development of stable gynodioecious genotypes for fruit and papain production.
• Exploitation of heterosis by producing F1 hybrids.
• Development of dwarf gynodioecious lines, and
• Breeding varieties resistant to “ring spot virus” .

20. Barriers in crop improvement
• Unpredictable sex expression and identification
• Lack of reliable genetic morphological markers for early screening
• Cumbersome and tedious process of maintenance of purity of the cultivars
• Lack of established vegetative method of propagation to produce true to type of
the elite material
• Ambisexual andromonoecious nature of some cultivaes