PINEAPPLE PRODUCTION
1. INTRODUCTION
Pineapple is one of the most important commercial tropical fruit in the world. It is important as an export product and as an industrial product. It is moreover a nice popular fruit.
Pineapple is ranked as the 6 th worldwide in terms of production volume. In Africa it is the 4 th , while in Tanzania it is also the sixth.
2. ORIGIN AND DISTRIBUTION
2.1 Origin
The origin of the pineapple cannot be determined with any degree of certainty. However, it is generally considered and accepted that the area of origin lie somewhere in Central and Southern Brazil (in the Amazon basin), Guyana, Northern Argentina, Panama and Paraguay. This is based on the fact that the wild foundation stock of the species may still be found in this tropical region of South America. The greatest diversity of clones, certain of which can not be classified according to the usual determination key is found there.
2.2 Distribution
Presently pineapple is grown commercially over a wide rage of latitudes from approximately 30 o N (the most northern location for field culture of pineapple is at 30 o 45 ‘ N in Assam India) to 33 o 58’S in South Africa at Port Elizabeth.
In the extreme latitude regions production is generally in near – coastal areas (or islands), where the climate is moderated by the ocean.
2.3 Production
Total World production of pineapple was in 1995, estimated at more than 12,000,000 tons. Major producing countries include: –
Asia – 64%: Thailand, Philippines, China, India and Vietnam.
American continent – 24%: Brazil, USA
(Hawaii), Mexico, Colombia and Costa Rica
Africa – 10%: South Africa, Cote d’Ivoire and
Zaire
In Tanzania: Production is estimated at 50,000 ton / year. Major producing areas are Coast, Morogoro, Kagera and Kigoma regions.
Out of the total word production (12m tons / yr.) 70% is consumed within the production areas.
Pineapple international trade is constituted basically of two major products: preserved or canned products and fresh fruits.
Data for 1995 indicates that, more than 1,000,000 tons of fruit were preserved and exported. The main exporters of preserved pineapple are Thailand and the Philippines, which exported 49 and 27%, respectively of the preserved product marketed internationally.
In the same year more than 500,000 tons of fresh fruits were exported. The main exporting countries are the Philippines and Cote d ‘Ivoire, which exported principally towards Japan and Europe. Substantial quantities of fresh fruits are also exported from Costa Rica and the Dominican Republic to the USA.
2. BOTANICAL DESCRIPTION
2.1 Classification
Class: Monocotyledonae
Family: Bromeliaceae
Genus: Pineapple
Species: comosus
The botanical name for the cultivated pineapple is thus: Ananas comosus (L). Merril.
The majority of plants belonging to the family Bromeliaceae are epiphytes (plants which depend on other plants or objects for support to a greater or lesser extent).
The pineapple is a terrestrial form comprising species of the genera Ananas and Pseudoananas. Other terrestrial forms include the genera Bromelia & Saginarius . The species of these genera are often referred to as wild pineapples. These bear small fruits which are full of hard seeds the size of rice grains. As a result they are barely edible.
Known wild species within the genus Ananas include; A. bracteatus, A. fritzmuelleri, A. electifolius and A. ananassoides.
2.2 Plant characteristics
2.2.1 The Plant
The pineapple is an herbaceous perennial monocotyledonous plant. At the adult stage (just before natural flowering) the pineapple plant measure 10 – 130 cm high, with a spread 130 – 150 cm in diameter.
The plant is constituted of a single central stem, that bears 2 types of roots (aerial and soil roots), leaves that completely covers the stem and suckers (shoot) in certain varieties.
The pineapple is often considered as a true xerophytic plant. Various morphological adaptations in its roots and leaves, confers to the plant a great ability of water economy. At the metabolic level, pineapple is one of the few commercially cultivated crop plants which possesses crassulacean acid metabolism CAM.
The pineapple can assimilate carbon either according to the system of C3 plants, under favorable climatic conditions, or according to the system CAM under strong photoperiods and water limiting conditions.
2.2.2 The Stem
The stem forms the axis of the plant. It is externally visible only when the leaves and roots are removed. The stem of the adult plant is very short and thick (shaped like a club). It has generally a length of 35cm and maximum, diameter of 7cm, with the thickest part lying just below the apex.
It has very short internodes from 0.1 to 1cm. This limited length of internodes is the cause of the clustering of and its complete covering by leaves.
The stem culminates into the apical meristem, while axillary meristems are distributed throughout its length in axils of the leaves.
2.2.3 The roots
Like many monocotys, the root system of the pineapple is adventitious. On the other hand, unlike others plants, pineapple forms 2 types of roots:
(i) The underground or Soil roots
Are roots with positive geotropism, and they develop in the soil. Their functions are:
– Ensure fixation of the plant into the soil.
– Feeding the plant by absorbing water and mineral nutrients from the soil.
Although some underground roots can penetrate up to a depth of 60 – 90 cm in the soil, the greatest proportion remains very superficial, localized within 15 – 20 cm of the soil surface. Emission of the underground roots begins shortly after planting and continues throughout the life period of the plant. The extent of emission and elongation depends essentially on the environmental conditions and the nature of the planting material.
(ii) Aerial or above ground roots
Are the roots formed within the axils of the leaves. They just enrol (wrap) themselves around the stem. They neither ramify (branch) nor penetrate the soil. They remain quite short, as they never grow to a height of more than 10 cm. These roots are known to have the following functions; –
– They play a role in the gaseous of the plant.
– Absorption of water from the atmosphere: either in the form of light rains or dew which never reach the soil and therefore can not be captured by the underground roots.
– Moreover, they are capable of absorbing nutrients elements supplied by spraying over the leaves.
2.2.4 Leaves
An adult plant will have approximately 70 – 80 leaves. These are arranged around the stem in a right or left spiral orientation. Due to their number and to the small dimension of the stem, they form a dense rosette with an erect spatial configuration (arrangement). In this rosette the youngest elements are located at the center and are not visible externally. The phyllotaxy for pineapple has been established to be 5/13 (every 13 th leaf is located directly above the initial leaf and five turns around the stem are made as the 13 th leaves are formed).
The leaves generally are semi-rigid, ly concave, with their width decreasing gradually from the base to the tip where they culminate in a spine. They have angles with respect to the plant axis which range from near 90 o (parallel to the soil surface) at the base of the plant to 0 0 at the top.
In dimension, the leaves measure up to 100 cm in length and 7 cm in width at mid-way between the base and the spine. Depending on the cultivar the leaf margins can be entirely spiny or smooth. In some cultivars the spines may be limited to the tip of the leaf only. However they can be numerous on leaves that differentiated during periods of poor growth.
The anatomy and morphology of the pineapple leaf reveal some particular characteristics:
(i) The shape and orientation of the leaves contribute significantly to the water economy of the plant, by channeling light rains and dew to the base of the plant
(ii) Much of the radiant energy falling on a pineapple plant is entrapped by multiple reflections within the rosette leaf array. As a consequence, the total reflectance of the canopy is low, resulting in albedo values that range from 0.14 to 0.16, implying that leaf heating reduced (ventilation is facilitated)
(iii) A thick cuticle covers the upper surface, which render it waterproof.
(iv) The lower surface is constituted of thick parenchyma cells which functions as a reservoir of water that can be drawn upon during periods of drought and that is replenished after adequate rain.
(v) Both the adaxial and abaxial leaf surfaces are covered by trichomes (being denser on the abaxial surface). They impart a silvery color to the leaf that increases its reflectance and by completely covering the leaf surface restrict loss of water vapor from the stomata.
(vi) Stomata are located only on the abaxial surface. They are moreover relatively few per unit leaf area (70 -85 / mm 2 ) and the stomatal pore is small.
vii) The cell of the upper epidermis contains anthocyanes, while those of the lower epidermis are rich silica. These may either reflect or focus light and increase leaf rigidity.
All these morphological and anatomical features reduce transpiration, results in a high water storage capacity and confer a high degree of drought tolerance to pineapple
2.2.5 Inflorescence and the fruit
When the plant has attained a certain level of growth (considered as the adult stage), it differentiates naturally (spontaneous) an inflorescence.
Floral induction occurs at the terminal meristem. The apical meristem is temporarily transformed into a floral meristem. This terminates (stops) the emission and the growth of leaves. The leaf primordia already initiated at this moment, will only have a limited growth and become leaf bracts borne on the eventual peduncle.
It has been shown that besides the level of growth attained by the plant, flowering is under the influence of climatic factors: is favored by short days, low radiations and low night temperatures.
The length of the vegetative growth phase; from planting to natural floral differentiation varies from 10 – 32 months. It is determined by:
(1) Characteristics of planting material, in terms of nature (type) and stage of development.
(2) Environmental conditions influencing plant growth.
Generally it varies inversely to temperature, and the size of the planting material. Temperature is considered as the most determining factor, particularly in influencing fruit development.
Pineapple is unique among cultivated plants in that its flowering can easily be induced artificially by using certain chemicals. The exact physiological roles or modification played or caused by these products of flowering are however still ignored. We only accept that the process is intimately.
The pineapple fruit is a syncarpe, formed by the fusion of all the individual fruit-lets issued from some 100 flowers, which form the inflorescence. The fruit develop parthenocarpically, since the flowers are normally self-sterile.
After the flowering phase, the apex re-differentiates vegetative structures, such that the fruit becomes surmounted or topped by a vegetative organ, which we call the crown.
2.2.6 The Shoots
The stem culminates into the apical or terminal meristem and that it is constituted of axillary meristems along its length. These are formed in the axils of each leaf, and they later on form axillary buds. These axillary buds are the origin of 3 types of shoots:
· Suckers are shoots which develop from axillary buds on the stem. They can develop from the underground portion of the stem, in which case they are referred to as ground suckers. When they develop from the above ground part of the stem they are called simply Suckers.
· Happas are shoots which develop high up the stem from axillary buds in the transition zone between the stem and the peduncle.
· Slips are shoots which develop in the axils of the bracts on the peduncle.
The crown is as well referred to as a shoot. For most cultivars, the formation of shoots will start only after floral differentiation or even after fruit harvest.
3. PLANT GROWTH AND DEVELOPMENT
The growth of pineapple is usually divided into 3 phases / stages:
- Vegetative growth (roots, stem and leaves) of the shoot that has been separated from the mother plant
- Growth of fruit (from floral differentiation to fruit harvest. It includes the growth of the crown and slips).
- Growth of shoot (suckers or ratoon).
3.1 Vegetative growth phase
The vegetative growth of the plant is indexed by the increase in the fresh weight. Up to flowering, the leaves represent 90% of the plant fresh weight (not including the roots). Consequently the stem represents only 10% of the total weight. For this reason, leaf growth is frequently considered to be representative of the whole plant growth. Growth of the total leaf mass comprises of increase in the number of leaves per plant and the increase in the mass of the individual leaves
The leaves are produced by the apical meristem according to a plastochron (or phyllochron), that is determined by the environmental conditions governing plant growth.
Growth of the leaf is basal; ie, the distal portion of the leaf is the oldest. The individual leaf grows in length and fresh weight. These reach their maximum values approximately 4 months after the appearance of the leaf in the heart of the rosette.
The leaves are therefore arranged along the stem from the base to the apical meristem according to age, with the oldest ones being those at the base.
They vary in form according to their position on the stem and therefore their age and have been grouped into 6 classes: –
A: Oldest leaves at the base of the stem already fully developed at planting. Have a zone of restriction near the base.
B: Leaves present at planting, but not fully developed they resume their growth, after planting and have restriction zone higher up towards the tip followed by the spine.
C: Oldest leaves developed after planting (neo-formed), have terminated growth.
D: Leaves that are terminating growth. Stand at 45 0 in the rosette, are used for leaf analysis, estimation of plant growth and yield.
E: Growing leaves not yet completely green.
F: Youwagen leaves – standing straight up and lightly colored.
3.2 Reproductive development phase
3.2.1 Flowering;
Flower initiation takes place at the terminal axis. This occurs naturally under the influence of the stage of plant development (indexed in terms of plant weight) and is favored or stimulated by climatic factors, particularly short and cool days. After initiation, the inflorescence appears in the center (heart) of the rosette 45 – 60 days later.
Although flowering occurs naturally only at certain times of the year, artificial induction of flowering with chemicals, called “forcing” can be done at any time of the year, if plants are large enough (1 – 1.5 kg of plant fresh weight).
3.2.2 Formation and growth of shoots
Crowns develop on top of the fruits after floral differentiation as a reversion process, from vegetative to floral development. They are therefore formed after floral differentiation.
Slips develop from the peduncle, therefore after floral differentiation. They are said to start growing immediately and at the same time or the inflorescence.
Their development stops shortly after fruit maturity. Usually they fall off the peduncle due to wind and their own weight.
Happas develop from the stem at the junction with the peduncle. Depending on the level of development of the plant, may start growing immediately after floral development.
Suckers develop from the stem, as a result of growth of axillary buds. In some cultivars, (eg, cv “Smooth cayenne”) axillary buds on the stem will start to develop at floral differentiation. Often they will only undergo active growth after the fruit is harvested. Nevertheless, only a few (1 – 3) may develop to from suckers. In some other varieties (eg, cv Queen Victoria), there exists a continuous development of the axillary buds on the stem throughout the vegetative and reproductive phases of the plant. There is consequently formation of many suckers, corresponding to the number of axillary buds / leaves formed. It is said that in the former cultivars, the buds are inhibited from growth due to apical dominance, resulting from the growing vegetative apex and eventually the first buds to develop. In the latter cultivars,
3.2.3 Fruit Development
On average, the duration from floral differentiation to maturity is 90 – 300 days. Climate and in particular, temperature is the determining factor. Hot conditions lead to shorter duration, while cool / cold conditions are associated with longer durations.
4. VARIETIES
Cultivated types of pineapple are called “Clones” because they are vegetatively propagated.
There are many types of clones classed in five groups: –
· Cayenne: – Cayenne lisse Hilo, Kew, Baronne de Rothschild.
· Spanish: – Cabezona, Singapore spanish
· Queen: – Queen Victoria, Natal Queen
· Pernambuco: – Yuppie, Sugarloaf
· Perolera: – Manzana, Maipure, Perolera
More than 60 clones / cultivars are grown in the world. However, they are not equally distributed. Clones of cayenne are the most cultivated. The cultivar “Smooth cayenne” being the most distributed and the most studied worldwide.
5. ECOLOGY
5.1 Climate
5.1.1 Temperature
From what we have seen on the distribution of pineapple, it can be said that temperature is the main environmental factor limiting extension of the production zone. Favorite temperatures are those ranging from 20 0 c and not exceeding 36 0 c.
5.1.2 Rainfall
Pineapple is often considered a true xerophytic plant, due to its high tolerance to drought. However, yields are severely reduced when adequate moisture is lacking. Evenly distributed rainfall of 600mm / year is said to be adequate for maximum growth.
5.1.3 Solar radiation
Good fruit quality requires a combination of relatively cool night temperatures and high percentage of sunny days.
5.2 Soils
Acid soils are considered suitable to pineapple. When soil pH is between 4.5 and 5.5, soil-borne diseases are reduced. Soil pH greater than 7.0 should be avoided.
Good soil drainage is necessary. Where rainfall is high or soils are not well drained, soil management techniques to improve drainage must be practiced.
Pineapple tolerates low soil fertility but best production is obtained with high fertility. High soil organic matter and potassium status are desirable while, high levels of soluble salt (Al and Mn) are tolerated.
6. CULTURAL TECHNIQUES
6.1 Propagation
Pineapple is propagated asexually from the 4 types of shoots already described. The number of these shoots produced on the plant varies with clone and climate. The choice between them is based on:
· Their availability as certain cultivars produce more or less of one or more type (s) of them.
· Suitability or their characteristics as shown in the table below
Characteristics of the different types of pineapple shoots used as planting materials
6.2 Land / Soil Preparation
Soil should be well tilled.
If the soil is imperfectly drained, beds of at least 20cm in height should be formed. If nematodes ( Pratylenchus spp. ) Are present in the soil, it should be sterilized, fumigated, or treated with a nematicide.
6.3 Planting
Field planting of pineapple is usually on beds, in a triangular planting pattern.
The most common plant population range from 40000 – 75000 plants per ha. Lower planting populations 40000 – 50000 being recommended for fruits destined for processing and the higher 60,000 – 750,000 ones for fresh fruit production.
Big fruits are required for processing and smaller sized fruits (1-1.5kg) for the fresh fruit market.
Fruit size decreases about 45g for each population increase of 2470 plants / ha.
In Reunion with cv “Queen Victoria, 3 – 4 rows are planted per bed, giving a plant population of 100000 plants / ha. Elsewhere with other cultivar much lower populations of up to 24,000 plants / ha. are practiced.
A spacing of 30 x 60 x 90; meaning 30cm in the row, 60cm between rows and 90cm between beds, gives a plant population of = 44,444 plants / ha.
Three or four – row beds are possible, but lead to more difficulties in plantation management, fruits from inner rows are usually smaller.
6.4 Mulching
Black polyethylene sheets approximately 90 – 100cm wide is used as mulch. The mulch is rolled out on the planting bed and its edges are covered with soil. Other material (common plant materials) can be used. Planting holes are punched through the plastic with a trowel or nails of a planting framework.
Advantages of mulch
Þ When nematicides are injected into the soil, the plastic mulch makes them more effective by slowing their dissipation.
Þ Mulch increases soil temperature in the root zone.
Þ Helps to conserve soil moisture
Þ Promotes rooting by concentrating moisture in the root zone.
Þ Help to suppress the growth of weeds.
Thus polyethylene mulch is commonly not used in areas with high temperature and moisture.
6.5 Weed Control
To control weeds on bare soil areas and in between the mulch beds, mechanical weeding is practiced. Otherwise pre-emergence herbicides (Bromacil, diuron) are very effective against grasses. Paraquat and ghyphosate are the best post-emergence herbicides.
6.6 Irrigation
Although pineapple is known to have a high capacity to survive drought, growth and yield are reduced, when water stress occurs.
Benefits of irrigation have consequently been reported in several pineapple growing regions; –
In Taiwan, a 30% yield increase was obtained when water was applied bi-weekly during fruit development.
In Cote d’Ivoire, yield increases of 12 – 15 ton / ha with irrigation were recorded. Differences of 25 – 30 ton / ha were recorded between irrigated and non irrigated plots when drought was severe.
In Guinea, growth of none irrigated plants was delayed for 3 – 3.5 months by the end of a 5 month dry season.
Pineapple can be irrigated by sprinkler (since some water is retained in the leaf bases).
Other systems include drip irrigation tubing laid in the center of each bed (under mulch) with one orifice for 12 plants, 1- 2 liters of water applied / plant / week.
6.7 Fertilization
Pineapple has high requirements for N, K and Fe, and relatively low requirements for P and Ca.
Requirements are highest when floral initiation approaches (2 – 4 months before). P and K are usually banded in the plant lines during bed preparation. K is usually applied to the soil before planting and later may be side dressed.
Other nutrients including K, are applied as foliar sprays or through the drip irrigation, or by both methods during the plant growth cycle.
Fertilizer rates are best determined by soil analysis. Optimum leaf nutrient levels (% dry matter) for cv “Smooth cayenne” are as follows:
N | 1.6 -1.9 |
P | 0.16 -0.20 |
K | 1.8 – 2.5 |
6.8 Artificial flower induction treatment (Forcing)
Pineapple cultivation is unique, due to artificial flowering induction.
By Flowering Induction Treatment (FIT), the grower becomes practically a master of his production cycles, as he can: –
- Harvest over a short period of time, plots which all the fruits have a simultaneous development.
- Ignore the natural fruiting cycles, and adjust production to the most favorable periods either in respect to market demand and prices or to climatic conditions for quality or technical reasons.
- Intervene on fruit size, since this is linked or proportional to the level of development of the plant at FIT time (up to certain limit).
- Shorten the length of the crop cycle.
- In general, it permits or facilitates the simplification of plantation management.
The most commonly used chemicals are; –
(i) Ethephon or Ethrel (2-chloroethylphosphonic acid) => an ethylene releasing compound. It is applied in a solution of 100 – 150 ppm, mixed with 2.5 – 5% urea (46%). 50 ml of the solution is poured into the heart of the rosette – with a sprayer.
(ii) Ethylene gas
(iii) acetylene gas (calcium carbide)
(iv) Naphthaleneacetic acid NAA and SNA
(v) Betahydroxyethylhydrazine (BOH)
(vi) 2, 4 – D => 50ml at 5 – 10 ppm.
(vii) Auxin derivatives.
Crop cycles when FIT is practiced
Under NFD, the duration of the crop crop varies from 10 – 32 months depending on climatic conditions. In warmer areas, the crop may require only 11 – 14 months; 6 -8 months for the vegetative phase and 5 – 6 months from forcing to harvest.
For the production of smaller fruits, the crop may be forced earlier than when larger fruits are required for canning. Ratoon crops may be forced 5 -7 months after the plant crop harvest, when suckers are formed early.
7. HARVESTING
7.1 Forecasting of harvesting date
The time between FIT, NFD and the harvest date varies with the climatic conditions.
Plants treated for FI during the hot period (t> 25 0 C) take 5 – 5 ½ months to reach harvesting time. NFD normally occurs at the beginning of the hot dry period and require the same duration.
When FIT is done at the beginning of the cool season, fruits take 7- 8 months to reach maturity, in particular when minimum temperatures (night temps) are below 25 o C.
The grower will have to record over several years, the FIT – harvest intervals for different periods of years, in order to establish the average interval which will be used in production planning.
7.2 Fruit Maturity determination
Harvest must occur at a stage when the fruit flesh maturity is good enough and therefore when the organoleptic qualities are satisfactory. The stage of maturity is determined by: –
(i) The external coloring of the fruit. The natural color change of the fruit at maturation starts from the base of the fruit upwards. That of fruit flesh as well.
4 color levels are identified; –
· Co = when the fruit is totally green on the outside.
· C1 = beginning of color change limited to the lower ¼ of the fruit.
· C2 = the influence half of the fruit is colored.
· C3 = 2/3 of the fruit are colored
· C4 = the whole of the fruit is colored.
(ii) Real fruit maturity cannot be judged only on the basis of the peel color. It is the state of the flesh itself which provide the exact determination.
Fruits can be sampled to visually appreciate the state of the flesh
Þ To determine the fruit juice content
Þ Analysis the sugar content (14% Brix or 14% ESS)
Þ To determine the optional sugar: acidity ratio (0.9 to 1.3 – sugar%, acidity Meq / l)
NB: Big fruits are often less colored than the small ones at the same level of maturity. There is also a lag between fruit coloring and fruit flesh maturity due to climate that would cause seasonal differences.
8. PEST AND DISEASES
8.1 Pests
Important pests in major pineapple growing areas are:
- Scales ( Diaspis bromeliae )
- Thrips ( Thrips tabaci ) – Vector of the yellow spot virus.
- Mites ( Steneotarsonemus ananas ).
- Mealybugs ( Dysmicoccus brevipes )
- Ants – associated with mealybugs
- Symphylids ( scutigerella sakimurai, Hansemilla unguiculata )
8.2 Diseases
- Root rot ( Phytophthora cinnamomi )
- Heart rot ( P. parasitica )
These are a problem in areas where soil drainage is poor or during periods of heavy rainfall. Are even more important where soils are alkaline.
· The pink disease
· The black spot
· Nematodes are also a problem in high pH soils.
It should be remembered that pineapple is usually monocultured (sometime for several continuous years without rotation) and based on a single cultivar and the repetitive use of a particular set of cultural practices.
This encourages the build up of pests and diseases, which can eliminate the pineapple culture (industry) in an area if efficient control measures are not developed.
References:
Py, C., Lacoeuilhe, JJ and Teisson, C. (1984). Pineapple its Cultivation and products. Techniques Agricoles et Productions Tropicales. Paris.
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