Pineapples are one of the world's most unique and exotic tropical fruits. They are perennial herbs and xerophytic plants which use water very efficiently.

Did you know...

• A pinepple takes 15-20 months to grow from planting to harvest
• A pineapple actually has blue flowers
• A mature pineapple is green
• Ready to eat pineapples can also be orange, yellow, red, or purple in colour!
• Pineapples contain an enzyme called bromalin. Because of this, fresh pineapple makes an excellent meat tenderizer

Varieties

Cultivated types of pineapple are called "clones," because they are vegetatively propagated. There are many named clones, classed in four or five groups including 'Cayenne', 'Spanish', 'Queen', and 'Pernambuco', which may represent botanical varieties.

Commercial production is mostly based on clones in the 'Cayenne' group, also known as 'Smooth Cayenne' because the leaf margins lack spines.

Description

Pineapples have narrow, tapering, pointed leaves up to 100 cm long arranged in a spiral rosettes that tightly clasp a central stem.

Leaf margins are usually lacking spines in Smooth Cayenne while spines are present in clones of the Spanish group. In Smooth Cayenne, the inflorescence consists of 100 to 200 flowers arranged in a compact spiral cluster. The flowers are perfect, with a floral bract, three short fleshy sepals and petals, six stamens, and an inferior ovary with three locules. Commercial clones are self-sterile but cross easily with plants in other groups.

The fruit is a terminal, cylindrical, compound structure at the apex of the stem and is formed by the fusion of the berrylike fruitlets that develop from the flowers. At its apex, the fruit bears a compressed, leafy shoot called a crown.

The typically yellow fruit flesh is best eaten when sweet and moderately acid; it may contain from 10 to 18 percent sugar and from 0.5 to 1.6 percent titratable acidity.

Flowering

Flower initiation takes place at the terminal axis of the stem. The flowering process (inflorescence) is not externally visible for 45 to 60 days, at which time it appears in the center (heart) of the plant. Staging development after appearance of the inflorescence is done by estimating the diameter of the opening in the center of the plant with common stages being "half-inch open heart" (1.25 cm) "one-inch open heart" (2.54 cm). The red inflorescence is clearly visible below the opening. Once the inflorescence emerges completely, the stages are referred to as "cones," with common stages being early, mid, and late cone.

Opening of the first flower occurs several days after the late cone stage, and blue flower petals can be seen at the bottom of the cone-shaped inflorescence. Before all flowers have opened, the earliest petals will have begun to dry. After all petals have dried, the inflorescence is said to be at the "dry petal" stage. Its surface is dull, individual fruitlets ("eyes") are pointed, and a crown has just begun to develop.

Although flowering occurs naturally only at certain times of year, artificial induction of flowering with chemicals, called "forcing," may be done at any time of year if the plants are large enough. This permits scheduling of planting and flowering so that harvests can be spread throughout the year. It is also used in "closing out" the crop to assure a complete and synchronous change at the time of natural flowering. Forcing is sometimes not completely effective during hot weather.

Production

Many of the culls are processed for juice concentrate, canned fruit or are also sold fresh.

Soil Types

Pineapples are grown on almost any type of soil, but the crop is especially well-adapted to acid soils. 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 a necessity. Where rainfall is high or soils are not well drained, soil management techniques such as ridging must be used to improve drainage.

Pineapple tolerates low soil fertility, but best production is obtained with high fertility. High levels of soluble soil aluminum and manganese are tolerated. High soil organic matter and potassium status are desirable.

Propagation

Pineapple is propagated asexually from various plant parts. For production purposes, the parts used are crowns, slips, hapas, and suckers, with crowns and slips being most common in the cooler tropics and suckers being more common in the warmer tropics (Côte d'Ivoire, Malaysia, Thailand). The number and proportion of slips, hapas, and suckers produced on the plant vary with clone and climate.

Harvest

When flower initiation occurs, ripe fruit is harvested six to eight months later. If flowering is initiated by chemical forcing at other times of the year, the period may be shorter or longer. Fruit is harvested by bending it over and twisting to remove it from the stalk.

'Smooth Cayenne' fruit is ripe when the individual eyes become flattened and glossy and when shell color turns yellow to yellow-orange. Color development starts at the base and moves toward the top. 'Smooth Cayenne' is harvested when about one-third yellow for canning and when mature green for fresh fruit.

Harvesting before ripening increases postharvest storage life, although harvesting when ripe is preferable for best fresh fruit quality.

Cultivars other than 'Smooth Cayenne' may be green, yellow, red, or purple when ready to eat.

Crop Cycle

Before the use of growth regulators to force floral initiation, plants could grow vegetatively for 10 to 16 months. Now, pineapple is planted all year round and forced nine to 13 months after planting. Duration of the "plant" crop is usually 15 to 20 months from planting to harvest. In warmer, equatorial tropical climates, the crop may require only 11 to 14 months: six to eight months for the vegetative phase and five to six months from forcing to harvest.

When smaller fruit is desired for the fresh fruit market, the crop may be forced earlier than when larger fruit is required for canning. The larger the plant at the time of forcing, the greater will be the size of its fruit.

After plant crop harvest, one or more suckers continue to grow to produce the ratoon crop. Ratoon crops are forced five to seven months after the plant crop harvest. Fruit of ratoons is usually smaller, sweeter, less acidic, and more aromatic than fruit of plant crops. A second ratoon can be taken in a good field having adequate soil fertility and low nematode populations.

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