BrProj

School Science Lessons
Breadfruit Project
Updated: 2008-07-16
Please send comments to: J.Elfick@uq.edu.au
See also: Interesting websites
See also: Tropical fruits

Preface
Before teaching this project, discuss the content of the lessons with a field officer of the Ministry of Agriculture and get advice on planting material, planting distances, site for planting, approved mulch, composting, and control of pests and diseases. Use only the procedures, agricultural chemicals and insecticides recommended by the local field officer of the Ministry of Agriculture. If you cannot control insects by hand-picking, ask the Ministry of Agriculture to recommend a chemical spray. All insect sprays are dangerous. Show the students how to use them safely. Do not get the spray onto your hands. Do not breathe in the spray. Wash your hands well after using spray. Keep the spray container in a safe place where students cannot get it. Spray on a day of no wind but if you must spray when there is a wind, spray down wind. Make sure the spray does not blow on other people.

Table of contents
1.0 Origin
2.0 Climate and soil
3.0 Tree and stem
4.0 Leaf
5.0 Roots
6.0 Male flower
7.0 Female flower
8.0 Pollination and germination
9.0 Fruit and seed
10.0 Cultivars
11.0 Seedlings
12.0 Suckers and cuttings
13.0 Planting
14.0 Harvesting
15.0 Fertilizers and shade
16.0 Pests and diseases
17.0 Breadfruit as a food
18.0 Other uses

Introduction
To teach this project you should have access to seedlings growing during the wet part of the year. Make a small shaded seed bed for growing the seedlings, and the cuttings.

1.0 Origin
Breadfruit comes from Papua New Guinea, Indonesia, Malaysia and Western Micronesia. Migrating Polynesians and Hawaiians brought it to Oahu Island, Hawaii. Seeded breadfruit may have been taken from the Philippines to Mexico and Central America by Spanish navigators. Later, in 1772 the French navigator Sonnerat in 1772 may have brought seeded breadfruit from the Philippines to the French West Indies. Following famine in Jamaica, in 1787, the British navigator Captain Bligh collected potted breadfruit plants from Tahiti but the plants used too much water leading to the famous "Mutiny on the Bounty" when the crew destroyed the breadfruit plants. However, in 1791 he collected different kinds of the plants and later took them to Jamaica where the seedless varieties later grew well. These varieties were later planted in the West Indies, Central America and northern South America. Jamaica and St. Lucia are now the main producers. In New Guinea, only the seeded type is grown for food and in Haiti the seeded variety is more common. The pulp of this large green fruit is used in the same way as potato and it stores well when dried or frozen.

2.0 Climate and soil
Breadfruit is suited to the hot and humid tropical lowlands. Although it is said that breadfruit need a temperature range of 16°-38°C, an annual rainfall of 200-250 cm, and a relative humidity of 70 to 80%. it can grow in dryer areas if irrigated and some large trees grow in temperate Brisbane. Similarly although it is said that the breadfruit tree must have deep, fertile, well-drained soil, in the Pacific Islands the seedless breadfruit grows on sandy coral soils, and seeded types grow on coral limestone islands. In Papua New Guinea, the breadfruit tree grows wild along waterways and in freshwater swamps. Perhaps each variety needs an environment with particular conditions. Some varieties are even salt tolerant.

3.0 Tree and stem
1. The breadfruit tree, Artocarpus altilis. (A. communis, A. incisus) belongs to the mulberry family, Moraceae and is monoecious. The normal, "wild type" has seeds and little pulp but it is still cultivated in some regions, e.g. Papua New Guinea. The "cultivated" seedless type is more widely grown, but sometimes seeds occur in seedless cultivars. The common name is usually a translation of "bread" and "fruit", e.g. "fruta de pan" in Spanish, "fruit a pain" in French. Some names distinguish the seedless variety from the seeded variety, e.g. "suku" and "kulur" in Malaysia. In the Philippines, the seedless variety is called "rimas" and in Hawaii "ulu". In some classifications, the seedless variety is called var. apyrena and the seeded variety, known as the breadnut, is called var. seminifera. In the southern hemisphere the breadfruit produces its fruit twice a year, in the period March to June and again in the period August to November. A good tree can produce more than one or two hundred fruit a year. Breadfruit does not normally grow wild by itself and it must be planted by man
2. The breadfruit tree is fast growing and the largest may reach 26 m in height, with a straight trunk to 6 m, 0.6-1.8 m in width and be buttressed at the base. The spreading branches may have lateral foliage bearing branches or long slender branches with leaves only at their tips. The young twigs are green in colour but soon become brown and woody. There are two kinds of marks on the small stems. The stipule scars are made when the stipules fall off. They are just below each leaf. There are many small brown marks on the stem, lenticels, that are breathing holes so that air can go inside the stem. All parts of the tree, including the unripe fruit, have a milky, sticky latex.

4.0 Leaf
See diagram 52.1: Leaf | See diagram 52.2: Stipule
1. Leaves are spirally arranged on the branch. The buds are 10-20 cm long covered with big, conical, light green stipules. Later, the stipule drops off leaving an obvious stipule scar on the branch.
2. The leaves may be evergreen on the wet tropics or deciduous in countries with a monsoon. In high rainfall islands, the leaves stay on the tree. In islands with a dry season, the leaves may drop off each year.
3. The leaves, are ovate, up to 20-90 cm long and 20-50 cm wide, and leathery. They are entire at the base then cut into 5 to 11 pointed lobes. The upper surface is bright green and glossy with yellow veins. The underside is dull yellow to pale green, rough below with minute, stiff hairs. The leaf has a short stout petiole 3-5 cm long and a strong midrib.
3. When a leaf is broken off a milky sap comes out, the latex.

5.0 Roots
1. Vegetative propagation is used so all the roots are adventitious roots with a dense occurrence of feeding roots close to the surface of the soil.
2. Dig up some feeding roots. Also get some bigger roots about 2 cm thick, because this is the size used to make root cuttings.

6.0 Male flower
See diagram 52.3: Male flowers | See diagram 52.4: Male inflorescence | See diagram 52.5: Male inflorescence
1. The breadfruit tree makes a multitude of tiny flowers, male and female. The female flowers form first.
2. The thousands of small male flowers grow closely together on a drooping, club-shaped spike. The flowers are 10-30 cm long, 2-4 cm thick, on stout peduncles (flower stalks) and are soft like a sponge. They are first pale yellow and then become brown. Each flower has a single small dark stamen that makes the male pollen. After the male flower comes out of the stipule, it takes early two weeks before the pollen is ready for fertilization when the wind blows the pollen onto the female flowers.
3. Examine a male flower. In the Southern Hemisphere this can only be done in early March or early August. Note the size of the small flowers and the dark stamen coming from each flower.
4. Pollen forms two weeks after the flower opens, and the wind blows the pollen to the female flowers.

7.0 Female flower
See diagram 52.6: Young fruit
1. The female flowers are massed in a rounded green head, about 6 cm long and 4 cm wide, and stand stiffly on stout peduncles. The female flowers appear about two weeks after the male flowers have first opened. The female flowers are tightly packed together and embedded in the receptacles with tubular calyx. From each flower comes the sticky part, the 2-lobed stigma which protrudes above the calyx, on a narrow style. Three days after the female flowers open, the stigmas can receive the pollen from the male flowers. At first the female flowers are small and held straight up. As the flower grows and turns into the fruit, the stalk bends down.

8.0 Pollination and germination
1. About 15 days after the inflorescence appears the male flowers shed pollen to be carried by the wind to the female flowers. Hand pollination improves the fruit set.
2. To observe how long it takes for one flower to grow to full size tie a piece of coloured cloth around one flower to identify it.

9.0 Fruit and seed
See diagram 52.7: Mature fruit | See diagram 52.8: Developing fruit
1. The whole inflorescence, all the flowers, develops into a compound fruit, a syncarp. The fruit is usually ovoid 9-45 cm in length and 5-30 cm in diameter. The thin fruit rind has a pattern of irregular, hexagonal faces in "smooth" fruits or have a sharp, black point or green pliable spine about 3 mm long on each face. Some fruits have a harsh rind like sandpaper. The rind is usually green at first then yellow or yellow-brown when ripe. When green, the fruit is hard and the inside is white, starchy and fibrous. The fruit is seedless or nearly seedless with a large central core surrounded by many aborted flowers which form a moist pulp. When ripe, the fruit is softer, the inside is cream coloured or yellow, pasty, and with a distinctive sweet smell.
2. The seeds are irregularly oval shape, rounded at one end, pointed at the other, about 2 cm long, brown with darker brown stripes. The seedless breadfruit is low in protein so the seeded breadfruit is more value as food! The seeds soon lose their viability if they become dry.
3. In the centre of seedless fruits is a cylindrical core. Some fruits are covered with hairs bearing brown, abortive seeds about 3 mm long. The fruit is borne singly or in clusters of two or three at the branch tips. The fruit stalk, pedicel, is from 2.5-12 cm long.

10.0 Cultivars
See diagram 52.9: Cultivars
1. Collect leaves of several varieties and take them into the classroom.
2. Describe each variety of breadfruit using the same descriptions as below.
3. The South Pacific Commission has published descriptions of about 160 varieties from the South Pacific islands. One variety from each class of Samoan varieties, classified by leaf shape, is described as follows:
Class I: Leaf entire (no toothing or division), or with 1 -3 lobes.
The "Tamaikora" fruit is gourd-shaped (constricted around the middle) 11.5 cm long, 7.5 cm, wide, and with many seeds. It can be eaten raw when ripe but is highly perishable. The tree grows to 12-13.5 m in height.
Class II: Leaf dissected at the apex
The "Temaipo" fruit is round, 9 cm long and seedless. It can be eaten raw when ripe.
Class III: Leaf moderately deeply dissected at apex
The "Uto Kuro" fruit is round, 12.5 cm long and does not deteriorate quickly.
Class IV: Leaf moderately deeply dissected on upper half
The "Tamaikora" fruit is oblong, 18-23 cm long, 12.5-16.5 cm wide, seeds sparse, pulp eaten raw when ripe. The tree grows to 23-26 m in height and bears 2 crops per year.
Class V: Leaf moderately deeply dissected, shape of leaf base variable
"Uto Wa" fruit is oval, 15-19 cm long, 12.5-14 cm wide.
Class VI: Leaf deeply dissected
"Uto Matala" fruit is round, 7.5-10 cm long and is especially fine when boiled. The tree bears 3 times a year.
Class VII: Leaf deeply dissected, apex pointed
"Balekana Ni Samoa" fruit is round, 12.5-14 cm long, seeds sparse. It is the best of all Samoan varieties.
Class VIII: Leaf deeply dissected, wide spaces between lobes
"Savisavi Ni Viti" fruit is oblong, 16-20 cm long, 10-15 cm wide, seedless, and is especially good when boiled.
4. Some varieties from Tahiti are described as follows:
The "Havana" fruit is oval to round. The rind is yellow-green and spiny. The pulp is golden yellow, moist, pasty, and separates into loose flakes when cooked quickly over fire to become very sweet with excellent flavour. The core is oval, large, and with a row of abortive seeds. The fruit is very perishable, so it must be used within 2 days. Fruit borne in 2"s and 3"s. It is said to be one of the best breadfruits.
The "Maohi" fruit is round and 15 cm wide. The rind is bright yellow-green with patches of red-brown, rough, with spines, and often has much exuded latex. The pulp is cream-coloured and smooth with very good flavour when cooked slowly. The core is large. Fruit is borne in 2"s and 3"s. This tree is a heavy bearer and is the most common breadfruit of Tahiti.
The "Paea" fruit is ellipsoidal, 28 cm long and 23 cm wide. The rind is yellow-green and spiny. The core is thick with a row of brown, abortive seeds. The pulp is bright yellow, moist, and separates into flakes when roasted for one hour on an open fire. Formerly, "Paea" was reserved for chiefs only.
The "Pucro" fruit is spherical or elongated and large. The rind is yellow-green with small brown spots, very rough, spiny, and thin. The pulp is light yellow and smooth, of excellent flavour. It cooks quickly and is said to be one of the best breadfruits.
"Rare Autia" The fruit is round, 15 cm across. The rind is dull green with red-brown markings. The pulp is light yellow when cooked and separates into chunks of excellent flavour. The core is large with small abortive seeds. This cultivar is so superior it was restricted to royalty and high chiefs only.

11.0 Seedlings
See diagram 52.8: Nursery
1. The seeded breadfruit is always grown from seeds, which must be planted when fairly fresh as they lose viability in a few weeks. Pick a ripe fruit. Leave it for three days until it is soft. Take out the seeds. Put the seeds on the floor in a dry, shady place and leave them for one day until they are dry. Then plant the seeds in the top of the seed bed and cover them lightly. Water the seeds. Keep the seeds watered each day. They will soon sprout. When the seedlings are two months old and between 15 and 20 cm high, they can be dug up and transplanted. Build a small shelter for a seed bed and put good soil in this place.

12.0 Suckers and cuttings
See diagram 52.10: Cuttings
1. The seedless breadfruit can be propagated by transplanting suckers from the roots. Suckers can be induced by uncovering and injuring a root. Pruning the parent tree will increase the number of suckers. Each sucker should be root-pruned several times for months before taking it up for transplanting.
2. Root cuttings 3-6 cm thick and 20 cm long should have the ends dipped in potassium permanganate solution to coagulate the latex, planted close together horizontally in sand in the shade and watered daily, After about 6 weeks, calluses form and after about 2 to 5 months, roots form. Then transplant the cuttings to pots, at a slant, and water daily for several months or until the plants are 60 cm high. Allow a period of full sun before the final transplanting.
2. Dig up some pieces of root about 2 cm thick or a little less. The pieces must be 20 cm long. Make sure to mark the top end. Make a sloping cut across the bottom end, as you see in the diagram. Plant the cutting in a covered seed bed in good soil and some compost. The cutting should be planted sloping, not straight up. The cutting must be watered often. The cutting can be planted out when it is about 15 cm. Plant the cutting with the top end out of the soil.
3. Breadfruit scions can be grafted or budded onto seedlings of jackfruit trees

13.0 Planting
See diagram: 52.11 Planting
1. Plant young breadfruit trees in holes 40 cm deep and 0.9 m wide, 7.5-12 m apart in plantations, about 80 trees per hectare. Prepare the holes by burning trash in them to sterilize the soil. Mix insecticide with the soil to protect the roots and shoots from grubs. Trees grown from root suckers should bear fruit in 5 years and be productive for about 50 years. Apply seasonal standard mixtures of NPK. When the trees reach bearing age, in addition apply 2 kg superphosphate per year to increase the size and quality of the fruits.
2. The hole for the plant must be 60 cm by 60 cm and 150 cm deep. Some growers put tin cans full of water in the bottom of the pit, then soil, then logs and coconut husks until the hole is 3/4 full, then compost and good black soil. Plant the young breadfruit in this good soil with the green shoot pointing straight up. Most breadfruit plants do not tolerate salt spray from the sea.

14.0 Harvesting
In the South Pacific, the tree usually fruits continuously with two or three main fruiting periods. So fruit in all stages of development are present during the year. In Hawaii, breadfruit are most abundant from July to February and in the Bahamas June to November. However, in most places some fruits may mature at other times during the year. Harvest breadfruits when maturity is indicated by small drops of latex on the surface of the rind and the fruit is still firm. If harvested by breaking the fruit stalk with a stick, some bruising or splitting may occur. If harvested by catching by hand, the leaked latex may cause some irritation. The yield varies from 25 to 200 fruits per year, 15-30 tonnes per hectare depending on the variety, climate and fertilizing procedures.

15.0 Fertilizers and shade
See also 6.9.14 Composting
1 The young breadfruit will grow much better if it is given some plant food. After planting in the it, some mixed fertilizer should be put on the soil around the base of the young plant but not too close to it. The fertilizer can be made by mixing together: 60 g of IBDU, 60 g of superphosphate, 30 g of potassium nitrate, 5 grams of coconut trace elements. This is the amount to put around one tree. This fertilizer should be put on the plant every three months. When the tree has grown bigger and has started to bear fruit, the following fertilizer mixture can be put on the soil every six months. 200 g of IBDU, 200 g of superphosphate 100 g of potassium nitrate 15 g of coconut trace elements. Mix some fertilizer and put it around the young plant. Give older plants a larger amount of mixed fertilizer.
2. In a very hot climate young plants should be given some shade from the hot sun, but some sun must shine on the plants. Make sure that if you shade plants you give them fertilizer.

16.0 Pests and diseases
1. The main insect pests are soft scales, mealy bugs and ants. Fungus diseases include soft rot of fruit caused by Rhizopus artocarpi that can be controlled by Bordeaux mixture. Rosellinia kills young trees and Fusarium causes die back, Pythium causes root rot. Phytophthora attacks the fruit, Phomopsis, Dothiorella and Phylospora cause stem end rot. Fruit flies can damage ripe fruits.
2. Some growers prune branches that have borne fruit and would normally die back to stimulate new shoots and keep the tree from growing too tall for convenient harvesting.

17.0 Breadfruit as a food
1. Most varieties of breadfruit are purgative if eaten raw so they must be boiled twice and the water thrown away before using them for food. However, some cultivars can be eaten without cooking. Some cultivars contain the sterol cycloartenol.
2. Breadfruit may be eaten ripe as a fruit or eaten underripe as a vegetable when it is picked while still starchy and boiled or roasted, sometimes stuffed with coconut before roasting. The pulp may be sliced and fried in palm sugar syrup until brown. Ripe fruits can be baked whole or steamed. Breadfruit soup can be made by boiling underripe slices. The pulp of ripe breadfruits can be combined with coconut milk and baked to make a breadfruit pudding. Breadfruit can be prepared as a sweet pickle. Overripe breadfruit can be used to make chips like potato chips or fries.
3. In some Pacific islands the fruits are peeled, the pulp mashed with sea water, sometimes baked or left raw, then left to ferment for some time in pits lined with banana leaves. The food called poi is made from boiled firm fruits, pounded to a paste with added water then strained through a cloth before eating.
4. The fruit can be preserved by being cut into slices, cooked and dried in the sun or dried over hot stones in a fire pit or dried in a copra dryer.
5. Dried fruit has been made into flour and combined with wheat flour or boiled to make porridge. Breadfruit flour contains 4.% protein, 77% carbohydrates, and 330 calories per 100 g. Cassava flour contains, 1% protein, 84% carbohydrates, and 347 calories per 100 g. Two enzymes occur in breadfruit, papayotin and artocarpine.
6. The fallen male flower spikes can be boiled as vegetables or candied by cooking in syrup. The seeds can be boiled or roasted before being eaten like chestnuts. Underripe fruits can be cooked for pig feed. The leaves can be eaten by livestock. The fruits can be kept under sea water until needed also ripe fruits fallen from the tree can be put into polyethylene bags and kept in refrigeration temperatures down to 12°C. Partly roasted fruits can be transported by sea. Canned breadfruit is exported to Europe.

18.0 Other uses
The latex was formerly used as birdlime to catch birds and for caulking canoes. The yellow grey wood with markings is light in weight, not hard but strong, elastic and usually termite resistant. It is used for house construction, furniture, partitions, surfboards and drums. The bark fibre can be used to make clothing, tapa cloth. Roasted leaves are used in local medicines.

History
These teaching materials were originally written and illustrated by Mr J. A. Sutherland, Faculty of Education, University of New England, Armidale, Australia and later edited by Dr J. Elfick, School of Education, University of Queensland, Brisbane, Australia.