This is the presentation given by Mr. Santosh Kalauni on " AYN Friday Sharing" program on 29- July-2016. The presentation was based on the research that is being carried out the Red lady variety of papaya. Mr. Kalauni is a student of MSc. Ag (Hort) at AFU, Rampur.

1. Glimpses of Ongoing Research on Papaya
(Carica papaya) var. Red Lady at Chitwan
Condition
Prepared By:
Santosh Kalauni

2. Introduction
 Carica papaya; F= Caricaceae
 Natural habitat= Tropical, Central and S.A.
 35 species within the family,
 1 monoecious(Vasconcellea monoica), 2 trioecious (Papaya and V.
cundi-marsensis) and 32 species are dioecious.
 Horticulturally imp. species
 C. papaya
 C. monica
 C. candamarcensis
 Use: Ascorbic Acid, Carotene, Riboflavin and Fair amount of Fe,
Ca, Thiamine, Niacin, Pantothenic acid, Vit. B6, Vit F
 Papain: Proteolytic Enzyme (Latex) obtained from the 12-34
mature fruits.

3. Introduction
 Varieties
 Gynodioecious Type= Pusa majesty, Pusa Delicious, Co 3 (Hybrid),
Honey Dew, Coorg honey Dew
 Dioecious Type= Pusa Dwarf, Pusa Nanha, Pusa Giant, Washington,
Co 1, Co 2.
 Sex Determination in Papaya: Hofmeyr and Storey independently
proposed sex determination in papaya controlled by a single gene
with three alleles, named as M1, M2, and m by Hofmeyr and M,
Mh, and m by Storey.
Mm Male individuals
Heterozygous
dominant
Mhm Hermaphrodite
individuals
mm Female individuals Homozygous
recessive
Dominant combinations of MM, MhMh, and MMh are lethal

4. Fig: Evolution of plant sexuality. Dioecy evolves from a hermaphrodite
ancestorthrough gynodioecy and monoecy, while androdioecious and
trioecious conditionsare derived from dioecious ancestors.

5. Sex ratio of crosses between different sex types
Crosses Sex Ratio
Female
(mm)
Male
(Mm)
Hemaphradit
e (Mhm)
Non-viable
(MhMh)
Male (Mm) selfed 1 2 0 1
Female x male (Mm) 1 1 0 0
Hermaphradite
(Mhm) selfed
1 0 2 1
Female (mm) x
hermaphradite
(Mhm)
1 0 1 0
Hermaphradite
(Mhm) x male (Mm)
1 1 1 1

7. Biology of Papaya Plant
Hermapharditic Flowers (How to distinguish them??)
 Petals fused on the lower part of the flower (connate), forming the
corolla tube. Upper parts of the petals are free and slightly twisted.
• Carpellody: Perfect papaya flowers may also undergo variable
degrees of fusion between their stamens (anthers) and the ovary.
• Pentadria Flower: Five antepetalous stamens are completely
transformed into carpels, and the resulting flower resembles a
female one, with a rounded ovary and free petals almost all along
their length.
• When hermaphardite papaya plants are subjected to stresses such as
high temperatures and water and nitrogen shortages, female
sterility is exacerbated leading in some cases to totally infertile
female (staminate) and unproductive inflorescence.

8. Carpelloid fruit
Pentadaria Flower
Hermapharidite Flower
Hermapharidite Flower

10.  Female Flower
• Female papaya flowers have five free petals and a rounded
superior ovary that is five carpellate and hollow and exhibits
parietal placentation. In contrast to the hermaphroditic plants,
females are completely stable and their flowers do not appear to
undergo sex reversal due to environmental fluctuations.
 Male Flower
• Stamen arrangement in the male flowers is the same as in the
hermaphrodite flower, surrounding a rudimentary pistil or
pistillode. In some cases, due to genetic or environmental causes,
some of the dominant flowers within the inflorescence may have
fully developed pistils, resulting in a hermapharditic flower and
an overall male, fruit-bearing phenotype.
Biology of Papaya Plant

11. Which one is better a hermaphradite or
female papaya trees for commercial
farmers???

12. Effect of Defoliation and Thinning on
the Quality and Yield of Papaya var. Red
Lady
Experiment I

13. Research Objectives
 Broad Objectives
 To assess the effects of fruit thinning and defoliation on the quality
and yield of Papaya var. Red Lady
 Specific Objectives
 To improve the fruit quality (size, color, sugar content) and
maintain consistent yield.
 To assess the source- sink relationship.
 To manage the orchard scientifically for reducing the spread of
disease and insect.
 To strengthen the plant physiology for adopting with the extremes
of climate change

14. Variety
• Red Lady (Gynodioecious line)
• Early (8-9 months), vigorous & high-yielding hybrid variety
• Potential yield= 120 t/ha
• Two year productive life cycle
• 50 to 120 fruits/tree
• Average fruit weight= 1.5 to 2 kg
• Semi-dwarf height
• Begins to bear fruit at 50 to 80 cm height.
• Fruit quality: Thick, firm, red flesh, great tasting, aromatic
and very sweet (13-14% sugar content)
• Highly tolerant to Papaya Ring spot Virus

15. Methodology
 Experimental Site: Model papaya farm of Chanauli, Chitwan,
Under Net House
 Experimental Design: RCBD
 Treatment Combinations: 9
 Replication= 3
 Number of Plant per Treatment: 2
 Observation taken: Plant height, number of leaves, petiole length,
leaf area, stem diameter, number of flowers and fruits, fruit weight
 Post harvest analysis: TSS, TA and Vit. C
Control
13rd Defoliation
23rd Defoliation
Defoliation
Control
Hand Thinning
Chemical Thinning
(NAA)
Thinning

16. Why Defoliation??
 Leaf to fruit ratio (source-sink ratio)
• Plant compensate 50% defoliation by increasing the
photosynthetic capacity of remaining leaf area (Boucher et
al.,1987).
• There is an increase in the photosynthetic rate on the recently
mature papaya leaves within 5 days of partial defoliated plants.
• But greater defoliation (60% to 75% leaves removed) could
reduce papaya fruit TSS and fruit flesh dry matter percentage
• Results shows that the reserve starch to compensate the short term
leaf loss, observed in the papaya stem and petioles (Jensen, 1962).
• Decreasing leaf-fruit ratios increase the photosynthetic efficiency
of the leaves but flower induction for the next growth cycle is
lower.
 Sexual expression: Hermaphrodite sps.

17. Why Thinning??
• Fruiting thinning ensures harmonious and rational distribution of
food and contributes to optimum fruit quality.

18. Experiment II
Effect of foliar spray of micro-nutrient (B
and Zn) on growth, yield and quality of Papaya
var. Red Lady at Chitwan Condition

19. Research Objectives
 Broad Objectives
 To assess the effects of micronutrient on the growth, yield and
quality of Papaya var. Red Lady
 Specific Objectives
 To improve the fruit quality (size, color, sugar content)
 To strengthen the plant physiology for adopting with the extremes
of climate change.

20. Essensiality of Boron
 Function: Cell division, Cell wall formation, maintain balance
betwn sugar and starch, pollination, seed development,
transpiration.
 Deficiency occurs in tropical region with heavy rain washing
away the nutrient and at very high pH in dry season making it
unavailble for the plants.
 Lumpyness in Papaya: First symptoms appear on shoot apical
meristem and in fruits.
 Non-fruiting Papaya: Young leaves become distorted, brittle,
and claw-like.
 Fruits develop 3-4 mm long cracks which ooze drips of latex.

21. Fig: A papaya fruit column showing
typical symptoms of boron deficiency
(photograph: Wayne Nishijima).
Fig: Leaves of boron-deficient papaya
plants may be de-formed and bunchy at
the apical meristem. They also may be
excessively brittle and claw-like
(photograph: Wayne Nishijima).

22. Fig: As the papaya fruits enlarge, the symptoms of boron deficiency may
become more severe (photograph: Wayne Nishijima).
Fig: Latex may bleed from boron-deficient papaya
fruits (photographs: Wayne Nishijima).

23. Essentiality of Zinc
• Function: Translocation of carbohydrates, N-metabolism, Acticity
of chlorophyll and functioning of several enzymes and growth
hormone, auxin.
• Severe stunting of leaves and shoots i.e. typical zinc def.
symptom is consequence of low auxin level.
• Deficiency: Irregular chlorosis of middle leaves, Short internodes
and petioles, marginal chlorosis of the lamina of middle leaves.
• Zn (0.5%) at 4th month after planting increased the fruit yield
(330.68 kgtree) and latex yield (21.65g/fruit) (Wang, 2005).
• Foliar sprays of Zn 0.5% + B 0.1% at 4th, 8th, 12th and 16th
month after planting improved the total number of fruits per tree,
fruit characters, fruit and latex yield (Kavitha et al., 2000a).

24. Methodology
 Experimental Site: Model papaya farm of Chanauli, Chitwan,
Under Net House
 Experimental Design: RCBD
 Treatment Combinations: 9 Replication= 3
 Number of Plant per Treatment: 2
 Spraying Time: Total 5 sprays
75, 90, 105, 120 & 135 DAP
 Observation taken: Plant height, number of leaves, petiole length,
leaf area, stem diameter, number of flowers and fruits, fruit weight
 Post harvest analysis: TSS, TA and Vit. C
Control
0.1%
0.2%
0.3%
Boron
Control
0.1%
0.2%
0.3%
Zinc

25. Experiment III
Effect of Different Packaging Material on the
Post Harvest Shelflife of Papaya var. Red Lady
from Chitwan to kathmandu

26. Intro.
 Fruit industry in Nepal even with huge potential but is
stagnant.
 Partly: Low production and consumption
 Losses incured during post harvest.
 Postharvest technologies not advanced
 Post harvest loss of perishable commodity in developing
country is around 50% (FAO Reports).
 High loss has been attributed to several factors among which
lack of packaging and storage facilities and poor means of
transportation are the major ones.
 No matter how good the quality, if packaging, transportation
and marketing are not properly taken fresh produce will
undergo rapid damage.

27. Objectives
 To study the effect of different packaging matierial on the post
harvest shelf life of papaya.
 To esitmate the total physiological weight loss (PWL) during
transportation from Chitwan to Ktm under different packaging
material.
 To study the effect of different maturity stage on the overall quality
and shelf life of papaya.

28. Experiment
Packaging Materials:
• Newspaper, grass, straw, cloth, styroform,
control.
Harvesting Time
• Early Green
• Color Break Stage
• Ripe Stage
Transportation loss i.e. PWL

29. THANK-YOU