Papaya plant

The Papaya tree (Carica papaya) is a tropical fruit that originated in Mexico and South America. It was taken to the Caribbean and Southeast Asia first and then spread to India, Oceania, and Africa.

It is now grown throughout the North American tropics and other tropical regions around the world. This large, short-lived perennial plant with a single trunk can reach up to 30 feet (9 m.) at maturity. Palmate leaves are deeply lobed and over 3 feet (1 m.) in width.

The fruit of the Papaya is also called pawpaw and is eaten raw without the skin. The papaya fruit is slightly sweet, with an agreeable musky tang, low in calories and high in potassium and vitamin A. Papaya is also used in drinks, jellies, salads, desserts and is also dried and candied.

Papaya grows best in sandy, well-drained soil. Papaya trees will not survive water-logged soil for more than a day. Papaya plants grow and fruit best in areas where temperatures remain warm to hot (70°F–90°F). Root growth is best if soil temperatures remain above 60°F and slows or declines below that temperature. Papaya is very frost sensitive; temperatures below 29°F will damage and may kill the tree.

Well-cared-for plants may begin to produce flowers 4 months after planting and fruit 7 to 11 months after planting. Generally, fruit is picked when there is 1/5 to 1/3 color change in the fruit. After picking, keep at room temperature to fully ripen. A ripe papaya will be aromatic and give slightly to gentle pressure. The flesh of ripe papayas is juicy with a buttery consistency. Ripe fruit will keep 4 to 7 days in the refrigerator.
Papaya plant

Rambutan tree

Rambutan (Nephelium lappaceum L.) is believed to be native to the Malay Archipelago, from where it spread westwards to Thailand, Burma, Sri Lanka and India; eastwards to Vietnam, the Philippines and Indonesia. The rambutan, a tropical fruit tree that belongs to Sapindaceae family includes about 125 genera and more than 1000 species of shrubs and trees which are widely distributed throughout the tropics and warm regions.

Nephelium lappaceum is an evergreen tree about 10-12 m tall; principal trunk is erect with an open crown of large branches; bark is slightly rugose, greyish or red.

The leaves are alternate, 10 –30 cm long, pinnate, with 3-11 leaflets, each leaflet 5–15 cm wide and 3-10cm broad, with an entire margin. The flowers are greenish white, short-petioled, apetalous, faintly odorous, and are covered with very fine short hair. The pedicels are thin, greenish yellow and densely rusty pubescent. The calyx is cup-shaped, 4-to 6-lobed, yellowish green and rusty tomantose outside and beset with short white hair within.

Fruit an ellipsoid to sub-globular schizocarp, up to 7 x 5 cm, weighing 20-95 g, usually consisting of only 1 nutlet, yellowish to purplish-red, hardly stalked, often finally dehiscing (at least the apical part), glabrous, usually densely set with filiform, curved, 0.5-2 cm long appendages; wall coriaceous, up to 2.5 mm thick. Seed covered by a usually thick, juicy, white to yellow, translucent sarcotesta.

The tree grows well in heights up to 500 meters above sea-level and grows best in deep soil; clay loam or sandy loam rich in organic matter. They thrive on hilly terrain due to good drainage.
Rambutan tree

Mandarin Orange (Citrus reticulate)

Fresh mandarin types of oranges are thin-skinned and are usually oblate or decidedly flattened at the ends. These oranges are a variety of orange that has a loose peel, popularly referred to as ‘loose jacket’ to distinguish it from the ‘light jacket’ of a normal orange, which has a peel that tightly adheres to the flesh.

Mandarin organs trees are more cold resistant and heat resistant than the other citrus species.  The trees on mandarin orange rootstock were approximately the same size as those on sweet orange.

mandarin orange

The mandarin orange tree is generally smaller than that of sweet orange. With age it may reach a height of 7-8 m, with a wide spread of branches and leaves. The tree usually has thorns, but its twigs are slender.

The trees yielded annually 350 dozen each tree and the more common varieties have produced 180 dozen.

The sandy soils in the high rainfall areas are suitable for growing mandarin orange.

Mandarin oranges thrive well on soil which have a natural sub-soil drainage system as water-logging around the roots of the plant during heavy roans in the monsoon is harmful to the plant life.

China is one the native homes of the mandarin oranges and has a cultivation history of about 4000 years.
Mandarin Orange (Citrus reticulate)

Palm oil tree (Elaeis guineensis)

Oil palm tree (Elaeis guineensis) is a monocot of the order of Arecales and belongs to family Palmae and subfamily Cocosideae.

Since 2006, the palm oil has overtaken soybean to become the most important oil crop in the world.

In East Asian countries, palm oil is the major feedstock for biodiesel. The period from 1995-2010, palm oil production more than tripled to 46.7 million MT, with Indonesia 47% and Malaysia 38% as the main producers.

USDA estimates that world palm oil production for  2014/2015 will be 63.29 million MT.

Palm oil is used for cooking, margarine, vanaspati, shortenings, detergents and cosmetics. It is also used in pharmaceuticals industry as a source of carotenes.

Oil palm trees are capable of producing palm oil all year round, rather than during just one or two harvests.

Oil palm wood is growing in value, especially with high demand from the United States, and even the cuttings and discarded fruit husks can be used in biofuel.

The oil palm is an unbranched evergreen tree, reaching a height of 18-30 m and having a stout trunk with diameter of 22-75 cm and covered with leaf bases.

Optimal plant density is 145 trees/hectare with a distance of 10m between trees.
Palm oil tree (Elaeis guineensis)

Cocoa crop

Cocoa, Theobroma cacao L., is a perennial crop, originally from the South and Central America and normally cultivated in the tropics from latitude 18 ° N to 15 ° S, mainly in small farms, under the shade of native trees.

The plant is grown for its fruits known as cocoa pods. When ripe, these pods are cut down and opened and the beans are removed. The pods contain seeds, which are fermented with mucilage surrounding them and then dried to give fermented dried cocoa, the raw material used in food industry.

Cocoa is now widely grown in the tropics, usually at altitudes less than 300 m above sea-level, where it needs a fairly high rainfall and good soil.

Rainfall must be plentiful and well distributed, with average monthly rainfalls in excess of 1500 mm.

Cocoa tress can take up to four years from planting before producing enough fruit to merit harvesting. They may live for 80 years or more, although the fully-productive period is usually about 20 years.

Cocoa trees do not reach full production capacity until they are roughly 10 years of age.

The cocoa beans are the major ingredients for the cocoa industry, for the manufacturing the chocolate and derivatives, cosmetics and medicines.

Cocoa processing takes place mainly in importing countries. The processes include shelling, roasting and grinding the beans. Almost half of each bean after shelling consists of a fat called cocoa butter.

In the manufacture of cocoa powder for use as a beverage this fat is largely removed.
Cocoa crop

The Tree of Mango

Mango is one of the most productive tropical plants. Mango contains protein, fat, carbohydrate, minerals, vitamins A, B, C, amino acids, resins, natural sugars, and citric tartaric and malic acids.

The mango tree is believed to have evolved as a canopy layer or emergent species of the tropical rainforest of South-east Asia.

The trunk of the tree is covered by a dark grey, cracked bark, when old. The young plant, to be sure, has a green outer skin called epidermis, like annual herbs.

Mature trees can attain a height of 40 m or more and can survive for several hundred years.

Mango trees that have been domesticated by selection from openly pollinated seedling populations show variation in tree architecture.

The tree is an arboresent evergreen. Leaves are simple and alternate, with petioles that range in length from 1 to 12.5 cm.

The petioles, besides placing the leaves in such position that they can get light, also save them from being torn when wind blows very strongly as they are springy.

Leaf morphology is highly variable, depending on the cultivar: leave can be lanceolate, oblong, ovate and intermediate types involving these forms.

Leaf length ranges from 12 to 38 cm and width can be between 2 -13 cm. Young leaves are copper colored, changing gradually to light and then dark green with age.

The leaves are spirally arranged in whorls and are produced in flushes. The canopy is normally oval, elongated or dome shaped.

The leaves of mango tree contain saponins, glycerine, sterols, polyphenols an benzoic acid and posses antibiotic properties.

Mango tree is able to keep its leaves on all the year round and thus can keep its root much cooler than a tree which has at times no leaves.

The juvenile period of seedling trees can range from 3 to 7 years. The root system consist of along, vigorous taproot and abundant surface feeder roots.
The Tree of Mango

Cultivation of Coffee Trees

Cultivation of Coffee Trees
The essential requirements for cultivation of coffee plants are water, illumination and ventilation.

The type of soil (edaphic factors) is less important; coffee trees grow as well in argillaceous-siliceous soil of granitic origin as in soil of volcanic origin.

However, the soil must be rich, with a pH between 4.5 and 6.0; also, the soil must be deep because root development is very extensive.

Coffea arabica is cultivated on plantations at altitudes of 3250 – 6500 feet (1000 – 2000 meters) where tropical climates are temperate.

Excessive heat and humidity are adverse conditions. Coffea canophera grows well in a tropical climate and needs atmospheric humidity near saturation.

Low temperatures around 32 degree F or temperatures above 86 degree F adversely affect coffee trees.

Even though coffee scrubs grow wild in shaded area, the coffee tress in highly productive plantations are cultivated in rows separated by banana tree and are well exposed to sunlight.

They are very sensitive to wind which explains the damage that cyclones can cause to coffee plantations.

Cultivation requires constant care and replacement of old trees with young plants obtained by germination of seeds or by cuttings.

Also, they must be protected from numerous parasites of which the most dangerous is rust caused by two fungi:
Hemileia vastatrix causes orange rust
Hemileia coffeicola results in flour like rust

A coffee tree attacked by rust loses its leaves. Other parasites (fungi, nematodes- thread worms, borers, scolytid-bark beetle, flies, pyralis-meal moth, crickets, caterpillars, bugs, etc) can also cause great damage.

Thus, it is necessary to ensure constant chemical or biological protection. For the past few years, this protection has been ensured by selecting coffee trees that are resistant to parasites without affecting the quality of the aroma of the finished product.

There is great hope that progress in genetic manipulation will result in long term improvement, especially since the chromosomal system of the coffee trees is now known.
Cultivation of Coffee Trees