Papayas

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Papayas
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World Production and Distribution

• World production 5,950 x 1000 mT.
• Major countries
• Brazil (1,500),
• Nigeria (748),
• Mexico (700) x 1000

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World Production and Distribution

• Distribution - throughout tropics, seeds store
  and ship well
• Permitted wide distribution, 23ENS latitude

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World Production and Distribution

• Not cold tolerant, -0.6 to -1EC. Grows poorly at
  low temperatures
• Many different types, sizes, shapes, colors
• Florida production, 250 acres

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Origin and Botany

• Originated in tropical Americas
• Disseminated around the world by Spanish from
  Americas

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Origin and Botany

• Family - Caricaceae - 3 genera, about 30 species
• Carica papaya L. Most important. Charactersitics
• Stiff unbranched trees, palmate, large leaves,
  dicot
• Milky sap, herbaceous

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Origin and Botany

• Some monoecious species, but usually dioecious
• Papaya is polygamous or hermaphroditic
• Flowers unisexual or bisexual

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Origin and Botany

• Vigorous growth, in full sun up to 9-10 m
• May live 20 years in some areas, but in Florida
  18-36 mos. Due to papaya ringspot virus, bunchy
  top

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Growth and Development

• Trees grown from seed, fairly uniform within a
  cultivar
• Root growth precedes shoot growth which is very
  rapid

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Growth and Development

• Leaves are laid down from apex, 10-20/mature
  plant
• Rapid vegetative growth until flowering, then
  growth slows
• Large, palmate, large petiole (60-90 cm long)

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Flowering

• Flowering - very complex, unusual, 8 types
• Flowers are cymose and originate from leaf axils
  .100 days after planting

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Flowering- Male Tree

• Flower morphology (dioecious to polygamous)
• All male flowers - produced on long racemes,
  flower tubular with 10 stamens in 2 series.
• No gynoecium.
• Thus, rarely fruit produced.

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Flowering-Female Tree

• Female tree - only female flowers, 5 petals
• Functional pistil (5 carpels)
• No stamens, pear-shaped flower

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Flowering-Female Tree

• Hermaphroditic - many forms
• Tubular contains both sexes, 5,5,10,5
• Stamens may become carpelloidic Fruit at low
  temp, excess N or water

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Flowering

• Environmental interaction (fig. 10.1, pg. 241,
  handout 1)
• Low temperature (winter carpellodic
• High temperature (35EC) bisexual becomes male
• Water stress, female sterility

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Flowering

• Hermaphrodite more prominent in summer. High
  temperature may lead to female sterility
• Anthesis timing ranges from 46-80 days depending
  on temperature

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Pollination and Fruit Set

• Usually self-fruitful, depends on flower
  morphology
• Wind pollinated
• Problems when dioecious and not enough males

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Pollination and Fruit Set

• Usual scheme 8-151 female male
• Fruit set variable, may be 85-95

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Fruit Characteristics

• Berry with 5 fused carpels
• Shape varies hermaphroditic-diverse
• Female, spherical
• Seeds black, parietal placentation, covered by
  sarcotesta

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Fruit Characteristics

• Fruit development - biphasic 0-80 then
  80-maturity
• Days to maturity vary 150-160 in tropics to
  190-270 in subtropics
• Starch is low, decreased rapidly 0-50 days, TSS
  increase nearer maturity, again temperature
  dependent

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Fruit Characteristics

• Composition (table 10.9, pg. 268, handout 2)
• Has moderate TSS, high in K, vitamins A and C
• Vitamin A especially in yellow and red cultivars
• Also source of papain, proteolytic enzyme
  collected by scoring fruit, collecting latex

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Cultivars (Pp. 254-255, Handout 3)

• Not true cultivars, propagated by OP seedlings
• Many have been inbred for years, e.g. Solo
• 100s of local cultivars vary in size, peel
  thickness, shape, color, flavor, aroma

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Cultivars (Pp. 254-255, Handout 3)

• Florida cultivars include Cariflora, Betty,
  Homestead
• Desirable characteristics include good vigor,
  less carpellody expression, smooth skin, good
  shape, and disease/pest resistance
• Cultivar list (pg. 254) - Nine pairs of
  chromosomes

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Cultural Practices

• Soils
• Sandy loams
• Volcanic must be well-drained and have pH 5.5-6.5

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Cultural Practices

• Climate
• Optimum temperature 21-33EC (effects growth and
  flowering)
• Moderate drought tolerance, in wet-dry need
  irrigation and RH 66
• Need wind breaks to prevent damage to trees and
  fruit

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Propagation

• Propagation and planting
• From seeds, selected, washed, dried, in flats
• Germinate in 10-15 days
• Transfer to containers for 1-2 mos., Acclimated
  to field

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Planting

• Field seed placed 20/hole to allow for losses and
  selection of proper flowering type
• Planted at 1600-2000 plants/ha

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Planting

• May be planted at 45 angle, lower height first
  fruit
• 2.0-2.5 m between and within rows, before rainy
  season

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Nutrition and Fertilization

• Varies with location, soil type
• Apply balanced fertilizer at planting and every
  few months
• Use leaf (soil) analysis - leaf, N 1.0-1.4, P
  0.15-0.18, K 2.5-3.5 minor elements

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Pruning

• Not usually necessary, except at harvest
• Weed control - standard practices

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Yields

• Variable, 45 kg/tree x 2000/ha 90 mT/ha at best

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Diseases- Fungi

• Phytophthora
• Pythium (damping off)
• Anthracnose, stem-end rot
• Fusarium, soft rot
• Rhizopus on fruit

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Diseases-Bacterial

• Bunchy top - stunting, yellowing vectored by
  leafhopper, cause unknown

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Diseases-Viral

• Papaya ring spot - worse - yellowing, stunting,
  aphid vectored
• Possible molecular biology controls (have in
  Hawaii), bunchy top

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Insects and Mites(Not Major Problems)

• Insects - fruit flies (see postharvest) include
  Mediterranean, Oriental, Caribbean (in fruit)
• Mites include broad, Texas citrus, red and black
  feed on young leaves and fruit

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• Other problems include
• birds, monkeys

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Harvesting

• Time varies with market - from ¼-½ for local to
  color break for long distance
• Also may be based on minimum TSS (Hawaii)
• Procedure by hand with a cutting tool then
  packed, shipped

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Postharvest

• Must treat for fruit fly if exporting to
  susceptible area
• Vapor heat - hot air 93 RH, 4 h so internal
  temperature 47.2 - can damage fruit (hot water
  used in past)
• Irradiation - useful with hot water, also may
  damage fruit

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Postharvest

• Generally - washed, fungicide, waxed and packed
• Proper handling is important to prevent bruises