Production of Avocado

1. AVOCADO
PRODUCTION
PREPARED BY; DANIEL NARINESINGH
INSTRUCTOR I

2. INTRODUCTION
• The scientific name for avocado is Persea Americana.
• It belongs to the laurel family (Lauraceae) is composed of
about 55 genera, with more than 2000 species.
• Some common names include alligator pear, butter pear,
aguacate and cura.
• They are mostly evergreen trees and shrubs, occasionally
aromatic, and native mostly to tropical and subtropical
regions.

3. INTRODUCTION
• There are three well-demarcated ecotypes of avocados, known as the
Guatemalan, Mexican and West Indian types.
• These races are recognized as subspecies:
• P. americana var. Americana (West Indian)
• P. americana var. drymifolia (Mexican)
• P. americana var. guatemalenis (Guatemalan)
• Due to the outbreeding nature of these taxa and human selection and
cultivation, there are many interracial hybrids and some of the
principal commercial cultivars are of hybrid origin.

4. Pollock
• A vigorous spreading West Indian type with an
oblong to pear shape fruit that weighs up to 2.27 kg
(5 lbs).
• Skin is thin and green.
• Pulp is deep yellow with medium thickness.
• The seed is loose within the fruit’s cavity and the
tree has an early July to August or October bearing.

5. Lula
• A Guatemalan and Mexican cross hybrid with a
tall, vigorous and upright growth habit.
• The fruit is pear shaped, sometimes with a neck
and seed tight within cavity.
• The skin is dark green and slightly rough.
• The pulp is greenish yellow and thin due to large
seed.
• The tree bears mid-November to December.

6. Simmonds
• A West Indian type with medium vigor.
• The fruit is oblong - oval to pear shape with seed
tight within cavity.
• The skin is green to light green in color and
smooth.
• The pulp is yellow and medium thick.
• It bears mid-July to mid-September.

7. Feurte
• The Fuerte Avocado is a medium to large fruit with an
elongated pyriform (pear) shape ranging from around five
to sixteen ounces.
• Its skin is smooth, easy to peel and its flesh is thick,
yellow and 18% oil.
• Its flavor is rich and creamy.

8. Hass
• Hass avocados are the only year-round variety.
• They're oval-shaped with a thick, pebbled skin that
turns from green to purple-black when ripe.
• They have creamy, pale green flesh with a classic
avocado flavor.

9. Origin & Distribution
• There is general agreement that the center of origin of
the avocado is in the eastern and central highlands of
Mexico and in the adjacent highland areas of Guatemala
to the Pacific coast.
• Early European travelers during the 16th century found
avocado in cultivation and distributed throughout
Central America and northern South America.
• This is evidenced by the native names given to avocado
in many languages and by archaeological findings.

10. Origin & Distribution
• The main producers are Mexico, the USA, Indonesia, Dominican
Republic, Colombia, Chile, Peru and Brazil, with Mexico, Chile,
Israel, Spain and South Africa being the main exporters.

11. Ecology
SOIL
• Avocado is grown in a wide variety of soil types.
• Deep soils of volcanic origin, sandy loam soils,
calcareous soils and other soil types have supported
good growth.
• Soil pH may range from 5 to around 7.
• Since avocado is highly susceptible to root rots, good
drainage is crucial and a high water table undesirable.
• Avocado has little tolerance for saline conditions.

12. Ecology
RAINFALL
• Most cultivars are sensitive to water stress and to excess moisture
caused by poor drainage.
• Generally, a moderate rainfall range between 1250 mm and 1750
mm per annum with good distribution is desirable.
• Avocado inflorescences are not damaged by moderate amounts of
rain for short periods, although relatively dry conditions are
preferred during flowering.
• Avocado roots are shallow, and prolonged dry conditions during the
critical periods of flowering and fruit set can cause flower and
young-fruit drop.

13. Ecology
Solar radiation and photoperiod
• Avocado is a typical C3 plant, with maximal CO2 exchange occurring at
20–25°C.
• Leaves take about 40 days from bud-break to when they become net
exporters of photoassimilates.
• During these 40 days leaves may compete with developing fruit for
available photoassimilates, and this competition influences fruit retention
and fruit development.
• Day length is apparently of little importance, as there have not been any
published studies on avocado responding to photoperiod.

14. Ecology
Wind
• The avocado tree is easily damaged by winds, due
to its brittle branches.
• Moderately high winds can cause severe damage.
• If orchards are not located in naturally sheltered
areas, windbreaks are advised.

15. Botany
TREE
• The avocado tree is variable in shape, from tall, upright trees to widely
spreading forms with multiple branches.
• Trees can attain heights of 15–18 m, with manageable height being
controlled by pruning.
• Although classified as an evergreen, some cultivars shed leaves during
flowering, which are replaced rapidly from terminal shoots.

16. Botany
TREE
• Flushes of shoot and root tend to alternate on a 30–60-day cycle.
• Root growth continues throughout the year in subtropical areas, even at a
low rate between the flushes, while shoot growth may stop.

17. Botany
FLOWER & INFLORESCENCE
• The small, pale green or yellowish-green flowers are borne on
multibranched axillary panicles terminating in a shoot bud.
• One or two million flowers may be produced in a single flowering
period, although only about 200–300 fruit mature.
• This flowering leads to considerable water loss, and the
recommendation is to irrigate during this period.
• The avocado flower has a unique flowering behavior, and all avocado
cultivars and seedlings, irrespective of race, fall into one of two
complementary groups, designated ‘A’ and ‘B’.

18. Avocado Flower

19. Botany
FLOWER & INFLORESCENCE
• Avocado flowers are perfect, bearing functional male and female
parts.
• They do, however, exhibit a unique mechanism for alternation of
sexes that enhances the opportunity for outcrossing.
• Avocado flowers are dichogamous, which means they first have a
distinctive female period with receptive stigma and a subsequent
male period when the stigma is generally considered no longer
receptive and the anthers dehisce to expose pollen.
• This mechanism prevents self pollination.

20. Botany
FLOWER & INFLORESCENCE
• A’ class open in the morning for 2–3 h, functioning as females with a
white stigma, while the stamens remain closed and are in a horizontal
position.
• These flowers close at approximately noon and reopen the following
day during the afternoon hours for 3–4 h, functioning now as males,
with stamens in a vertical position.
• The stigmas are no longer functional.
• Flowers of the ‘B’ class open in the afternoon as females, the stamens
remaining closed.
• These flowers close in the evening and reopen the next morning as
male flowers.

21. Botany
FRUIT
• The avocado fruit is a one-seeded berry.
• The single large seed is composed of two cotyledons
enclosing an embryo and is surrounded by a thick fleshy
mesocarp.
• The skin color of the ripe fruit ranges from several
shades of green to yellow-green, from reddish to maroon
and from light to dark purple.
• The buttery flesh (mesocarp) is greenish-yellow to
bright yellow to cream when ripe.

22. Image of the Fruit

23. PROPAGATION
• Avocado is primarily propagated commercially by
grafting upon seedling rootstocks.
• Air layers and cuttings have been successfully rooted.
• However, the variability of seedling populations with
respect to certain desirable characteristics, such as
resistance to Phytophthora root rot and tolerance to
salinity and calcareous soils, has posed problems.

24. PROPAGATION
• Seeds for rootstocks are planted (broad side down) in
polyethylene bags, with a well-draining potting mix. The
papery seed coats should be removed.
• Seeds germinate in about a month.
• Seedlings may be cleft or side-wedge grafted 2–4 weeks after
germination.
• Grafted plants must be hardened for approximately 2 weeks
under full sunlight before field transplanting.

25. LAND PREPARATION
• Land preparation for avocado does not differ from
that for other tree crops.
• Development of a drainage system is a prime
consideration.
• If soil Ph needs adjusting, this could be done during
the final stages of land preparation.
• Cover crops, such as legumes or grain, can be pre-
planted a year before orchard planting to increase
organic matter and minimize erosion and root rot.

26. Spacing
Characteristics influencing spacing:
• The cultivar’s natural growth habit (spreading or erect)
• Vigour of the rootstock
• Environment and soils
• Encouraged thinning practices.
• Inter Spacing (7 - 10m)
• Intra Spacing (7 - 12m)

27. Pruning
• Pruning is essential in avocado production since it facilitates
increase in yields.
• Since avocado is polyaxial, it must continue to increase in
size to remain productive.
• Pruning aims at a canopy that has fruit at all heights and
reduces the competition for light.
• Pruning at the bud ring (several closely spaced buds without
subtending leaves), formed at the conclusion of a shoot
growth flush, releases more buds and increases shoot
complexity, and hence bearing sites.
• Cutting below this ring depresses tree vigor and releases
only one bud.

29. IRRIGATION
• The avocado can tolerate neither water stress nor excess moisture, especially when
drainage is inadequate.
• Water stress reduces yields, fruit size and tree vigor.
• The soil around the trees should be moist but not wet.
• Irrigation frequency depends upon field condition, soil drainage and tree density, as
well as canopy size and prevailing weather conditions.
• Only 50% of the tree’s requirements should be given in the middle of the cool season
and spring, in order to favor flowering rather than vegetative growth.
• When fruit set is completed, irrigation reverts to normal amounts during fruit
development.
• High irrigation rates are necessary during flowering and may be necessary as the
fruits approach maturity and if the weather is hot and dry.

30. Fertilizer Management
• Fertilizer practices differ in avocado-producing areas, due
to differences in climate, soil, cultivars and management
practices.
• Nitrogen seems to be one of the controlling factors in
avocado yields.
• P and K should also occur near the peak of fruit set.
• Key Nutrients through out plant cycle:
• N, P, K, Ca, Mg, Fe, Mn

31. Pest and Disease Management
• A number of avocado diseases have been reported
from producing areas around the world, the most
serious being root rot caused by P. cinnamomi
Rands.
• This is suspected when trees show a gradual
decline, with leaves becoming smaller, yellow-
green in color and shedding.
• In severe cases, twig dieback occurs.

32. Control
• The root rot fungus can be easily spread by any means that
moist soil is moved, or in drainage water from diseased
areas hence sanitation is a good agricultural practice that
helps to reduce such disease.
• Improving plant vigour, restoring the equilibrium between
the root and foliar systems.
• P. cinnamomi can be killed or prevented from growing by
many other types of chemicals including chemicals
containing copper.

33. Pest and Disease Management
• Anthracnose of avocado (Persea americana) is a common
fruit disease causing severe losses during marketing and
in storage.
• Infections, caused by the fungus Colletotrichum
gloeosporioides, create rounded, dark-colored, sunken
lesions that expand rapidly on the fruit skin and into the
pulp, causing rot.

34. Control
• Choice of planting location. Avoid planting avocado in areas that are
prone to strong winds, as branches broken or moved by windstorms can
damage avocado fruits, creating openings in the skins for avocado
diseases to infect.
• Cropping system. Planting avocado trees at least 25 feet apart allows
good aeration of the canopies of mature trees, so wet fruits and foliage
dry quickly after rainfall, which helps to inhibit infections
• Fungicides. Sprays of fungicide may be required at 14-day intervals from
fruit set to fruit harvest.
• Sanitation in the field. Pick up fallen plant debris and remove it from the
field.

35. Pest and Disease Management
• There are many insect pests reported in avocado
orchards, although they do not usually pose any serious
problems.
• Insects such as scales, aphids, mealy bugs and various
mite species are also commonly found in orchards, but
natural enemies have been shown to provide satisfactory
control.
• Some fruit flies may also be prevalent but do not pose any
significant problems.

36. Weed Control
• Young avocado trees are sensitive to herbicides, so
weeding around the trees is usually done manually.
• Other cultural practices such as mulching and various
types of irrigation systems also helps to reduce weeds.
• However when plants mature, the canopy provides
enough shade to prevent weed growth.

38. Harvesting
• A major problem is the stage of maturity for harvest,
especially for cultivars that remain green upon ripening.
• Some avocados will start changing skin color and then
fall from the tree when mature. Maturity of cultivars that
normally change skin color from green to reddish or
purplish, such as ‘Hass’, is easy to ascertain.
• Immature fruit, if harvested, take longer to soften and
they shrivel upon storage, with the flesh becoming
‘rubbery’ rather than buttery.

39. Harvesting
Harvesting Indices:
• The increase in oil content (8% min) is correlated significantly with
maturity.
• However, determination of the oil content of avocado fruit is expensive,
time consuming, and tedious, especially for growers who lack the
necessary laboratory and equipment.
• Moisture content is also used as a measure of maturity, as it does not
involve oil determination, and there is a negative correlation between
oil and moisture content.
• Skin texture and appearance is an indicator of harvest maturity in
most avocado cultivars.
• As fruit approach maturity, they develop a smoother skin surface.
• Also, the glossiness or shine of the skin becomes duller as the fruit
reaches maturity.