You are here

Horticulture

It is important to understand how to best cultivate breadfruit trees to maximize their potential for health and production. Fortunately, breadfruit is a very hearty tree by nature and requires fewer resources than other crops, and is relatively maintenance-free tree. Learning about the best practices for tree care improves the probability of greater fruit yield and a longer life for your tree, and provides the knowledge needed to produce more healthy plants.

Propagation

Thousands of years ago, Pacific Islanders would venture out into the unknown seeking new lands to call home with canoes full of the plants they knew would need to survive, including the root shoots and seeds of breadfruit trees. The methods of propagating breadfruit trees have changed and grown with new research and technologies, but the basic idea of producing new plants from a mother tree remains constant.

In general, breadfruit is vegetatively propagated using root shoots or root cuttings. Vegetative propagation refers to producing new plants from vegetative parts of the original plant, such as from the buds and roots. The main advantage to this is that the new plants contain the genetic material of one parent, so they are essentially clones of that parent plant. Once you have a plant with desirable traits, you can reproduce the same traits over and over again indefinitely, as long as the growing conditions remain similar.

Other methods include seed propagation, grafting, air layering (marcotting), and in vitro (tissue culture) propagation. No matter the method used, young plants will grow best in shade and need some care until they are established. Mature trees prefer full sun. Breadfruit grown from seed will fruit in 5 to 10 years. Seedless varieties must be vegetatively propagated and this method is also preferred for seeded types as the trees are clones of the mother plant.

Seeds

One of the oldest methods used to propagate breadfruit trees is to grow them from seeds. Remove seeds from soft, ripe fruits and wash to remove any pulp. Plant immediately because the seeds lose viability–ability to sprout and grow–within a few weeks. Seeds cannot be stored and are damaged by chilling or drying. Plant in loose, well-drained soil and keep moist, but not wet. Seeds germinate within 10-14 days. Seedlings grow quickly and are ready to plant into the field in about one year. Propagation by seed has become more difficult in modern times because many of the most desirable varieties have evolved to become seedless, causing a greater need to develop and perfect new and traditional methods to grow new trees.

Root Shoots

Root shoots are new breadfruit trees that grow from the root system of the mother. Roots typically grow on or slightly below the surface of the ground and often produce a shoot, especially when wounded or injured. When the shoot is at least 0.3 m tall, detach it from the mother plant by severing the root 10 to 15 cm on either side of the shoot. Be careful not to damage the tender roots at the base of the shoot. Trim off the large leaves and plant in a pot with well-drained soil until the plant is larger. If directly transplanted into the field, place in a hole amended with organic material, and provide shade and keep moist until established. Root shoots should be removed from the mother tree to maintain tree health, as they drain resources such as water and nutrients, and prevent air flow and light penetration as they grow larger.

Root Cuttings

Sections of roots can also be used as propagating material. It is best to collect roots after the fruiting season is over and when the tree is in an active vegetative stage, producing new leaves. This generally coincides with the end of the dry season and root cuttings should be collected as the rainy season begins. This is when carbohydrate stores in the roots are highest, increasing the success rate of the cuttings. Select healthy roots growing slightly below the soil that are 1.5 to 6 cm in diameter (3-4 cm is best). Cut into 12 to 30 cm long sections. Roots should be scrubbed clean and kept moist. Plant directly into the ground in loose, organic soil or in a pot with well-drained soil. Roots can be oriented horizontally below the surface of the soil or diagonally with the upper few centimeters exposed to air.

Air Layering

Air layering (or marcotting) involves cutting part way into a stem or branch and packing the area with a moist medium to stimulate root formation, so that the stem or branch can be removed and grown as an independent plant. It is best to air layer branches at the beginning of the rainy season when the tree is in an active vegetative stage, meaning the period of growth between germination and flowering. Select newly developed shoots (2-4 cm diameter) and do not use the ends of branches that have previously flowered or fruited. Carefully remove a 3 to 5 cm strip of the outer bark around the circumference of the branch leaving a narrow, vertical connecting strip. Wrap moistened sphagnum moss, compost, or other organic material around the area. Rooting hormone can be added, but is not required. Tie a piece of burlap, plastic, etc., around the organic material to hold it in place. After 2 to 6 months, new roots will develop and grow through the media. Remove the air layer by cutting the branch directly below the roots. Place in a pot with well-drained soil until the plant is larger and has an established root system (about one year). Transplant into the ground. Depending on the size of the original branch, air-layered branches can fruit in 3 to 4 years.

Grafting

Grafting involves uniting (joining) a bud or shoot of one plant (scion) to another plant (stock). Several methods have been successful with breadfruit, including cleft, slice, and approach grafts. Thin cuts, 5 to 7 cm long, are made in equal-sized branches of the scion and stock. The two branches are carefully brought together at the wounded area and tightly wrapped. It is essential that the cambial layer (actively growing part of the branch) of scion and stock plant are in contact. Once the graft has fused together the scion can be separated from its parent plant. Grafting different varieties of trees together can reduce the time to first production of fruit and flowers, and can allow one tree to extend its growing season by producing fruit of more than one variety.

Tissue Culture (In vitro) Propagation

Each individual plant cell has the potential to become a whole plant in the right conditions. In vitro (tissue culture) propagation is a recently developed method to propagate breadfruit trees. Buds, shoots, or other small vegetative parts of the plant are thoroughly, washed and disinfested to reduce pathogens, such as fungus and bacteria, cut into small pieces, and placed in a growing medium. The growing medium provides the necessary vitamins, nutrients, and growth regulators to grow a plant identical to the original source plant. The best composition of the medium is different for each variety, and can take several years to optimize. The resulting young plant is not genetically modified (GMO), rather it is a copy, or clone, of the parent plant.

Bananas, plantains, taro, sweet potatoes, yams, and other crops are widely produced using tissue culture. Farmers throughout the tropics and subtropics rely upon this technology for disease-free planting material—plants free of viruses, bacteria, and fungi—that meet international plant quarantine requirements.

Soil

Pacific Islanders treasured breadfruit trees for their ability to not only adapt, but to thrive in conditions where other crops could not survive. Breadfruit prefers deep, fertile, well-drained soils, yet some varieties thrive on atolls with saline and coralline soils, where the ground is shallow and sandy. The tree prefers light and medium soils (sandy, sandy loams, loams, sandy clay loams) that freely drain with acidity that is neutral to alkaline (pH 7.4-6.1). The trees also grow well in conditions where the soil is rocky or considered not stable, such as on steep hillsides.

When planting a breadfruit tree, ideally the soil used should be a mix of field soil and planting soil, compost, aged manure, or any other beneficial soil additives. This relatively low-maintenance species can be fertilized once a year with a balanced NPK fertilizer, but trees can produce abundantly and thrive for years without supplemental fertilizing. Fertilizer is only a temporary solution to assist plant growth and will not solve the problems of poor soil with little organic material, bad drainage, and inconsistent care. A constant commitment to improving soil structure through mulching, planting cover crops, and the addition of organic material to revitalize the soil on a regular basis will help guarantee your trees a long, healthy, and productive life.  

Planting

Planting a breadfruit tree not only provides an abundance of nutritious food for you and your community, it is beneficial to the environment. Breadfruit does best in well-drained soils. Amend soil with organic material prior to planting, and dig a hole two times as wide but just slightly deeper than the size of the root ball. Water, as needed, until the tree is established, generally within one year. Trees prefer full sun but do best if shade is provided when they are young. Mulching with the large fallen leaves and other organic materials is beneficial and provides nutrients, protects roots, and helps keep the soil moist during dry periods. The tree can readily be pruned and shaped to keep it low and make harvesting easier. Download our Planting Guide for more information before placing the young tree in the ground. Available in English, Hawaiian, Chuukese, Samoan, and Tongan.

Pests and Diseases

Breadfruit is relatively disease and pest-free with most problems occurring regionally. The most common widespread problems include white fly, scale, mealy bugs, Cercospora leaf spot, and fruit rots caused by Phytophthora, Colletotrichum (anthracnose), and Rhizopus. The best way to deal with fruit rots is to remove affected fruits from the tree and not allow fruits to ripen on the tree or rot on the ground. Breadfruit is also a fruit fly host which currently limits the export potential of fresh fruits. Phellinus noxius, a root rot, can be a serious problem, especially when trees are planted in areas of recently cleared forest.