Plant propagation of subtropical and tropical fruit

crops for the home landscape

Jonathan H. Crane, Tropical Fruit Crop Specialist

University of Florida, IFASTropical Research and

Education Center, Homestead

Types of plant propagation

• Seedage (by seed)• Air-layering

(marcottage)• Cuttings• Suckers

• Stooling*• Grafting• Budding

*, not common for propagation of subtropical and tropical fruit crops

Supplies for seedage, marcottage, and cuttings

• Soil media– Sterile and clean– Well drained

• Containers for seed and cuttings

• Clippers, knives• Labels• Rooting hormone

• Marcottage– Knives– Clippers/loppers– Polyethylene

plastic and/or tinfoil

– Plastic flagging tape

Soil media

Seedage and cuttings

• Mixtures of peatmoss, perlite, vermiculite, course sand, clean soil, clean compost

Marcottage• Clean sphagnum

moss

Seedage• Most fruit trees may

be propagated by seed. However, seedlings have two potential drawbacks– They do not

always come true to cultivar.

– They usually take longer to flower and fruit.

• However, seedlings are commonly used as rootstocks for avocado, mango, carambola, loquat, mamey sapote, and citrus.

Seedage

• Remove seed from mature/ripe fruit, wash thoroughly and air dry in the shade.

• If seed is to be stored for more than 3-4 days then consider treating seed with a fungicide or 1% chlorine solution during washing (use gloves!), then air dry.

• Store in cool (50-55oF) dark area.

• Many tropical fruit seeds are recalcitrant – meaning, they do not store for very long before they lose viability.

• Examples include avocado, mango, lychee, longan, and carambola.

• In contrast, atemoya, sugar apple, and papaya store for several years.

Seedage steps for selected tropical fruit crops

• Avocado: remove outer integument (papery) tissue, rinse*, air dry, plant flat (top) upside down ~1/2” down into soil.

• Mango: remove outer husk, FD, plant horizontally just under media.

• Papaya: remove seed and outer gelatinous sac, rinse*, air dry, poke ¼-1/2” hole in media, drop in seed and cover.

• Carambola: remove seed, rinse*, air dry, plant into ¼-1/2” hole and cover.

*, remove dirt and/or gelatinous coatings

Marcottage (air-layering)

• Select a branch that is ½ to 2 inches in dia. at 12 to 36 inches from the terminal end of the branch.

12”-36” long

Marcottage (air-layering)

• Girdle the branch by removing a ring of bark ½ to2 inches in width and scrape away any soft tissue tothe wood surface.

½” - 2” girdle

bark barkwood below bark

Marcottage (air-layering)

• Take about 2 handfuls of sphagnum moss that hasbeen soaking overnight, squeeze it to remove mostof the water and place it around the girdle. Thenwrap with plastic or tin foil (secure ends).

wrap

sphagnum moss

Marcottage (air-layering)

• Completed air-layer; leave this in tact for 3 or more months depending upon temperatures and periodically check for signs of rooting. Whenrooted remove from tree.

cut behind the air-layer

Marcottage (air-layering)

• Rooted and removed marcott

fresh, healthyroots

After care of marcotts

• Remove marcott from mother tree with clippers or loppers; make a cut behind the root ball.

• The roots of marcotts are only superficially attached to the new plant therefore handle the plant gently – jolting/dropping/throwing will detach the roots and kill the new plant.

• Pot the new marcott into a 3-gal or larger pot; plant it 2-3 inches deep; stake the plant.

• Place the plant into a shade house (1 month of periodic misting will help) for 1-3 months.

• Fertilize with dilute solutions, water as needed.

• Be careful not to drop or roughly handle containers of murcotted trees as this may damage the new root system.

Propagation by cuttings –four components for success

1- Rooting hormones are effective in stimulating and hastening rooting.

• IBA (indolebutryic acid) and NAA (naphthaleneacetic acid) are the two most common: follow the directions.

2- High relative humidity. Professional propagators use intermittent mist beds, however, these require some expertise to construct and may be impractical for most homeowners. Try using polyethylene bags with periodic sprinkling.

Propagation by cuttings –additional technology

3 – Use clean well drained media for rooting cuttings; use a combination of peatmoss and perlite or vermiculite.

4 - Place the cuttings that have been put into clean soil media in a warm but shaded location – this will improve the speed callus and roots are formed, i.e., improves the rooting of cuttings.

Propagation by cuttingsHardwood, semi-hardwood and soft-wood

Hardwood cuttings are taken from the previous seasons growth (1/4-3/4”: 6-20 mm in dia.) and are 6-12” (15-20 cm) long.

Usually the cuttings are bundled together, placed horizontally into a box and covered with moist, sterile media, placed in a warm shady location.

• After the bases of the cuttings have formed callus they are planted into the propagation media (basal side down).

• Hardwood cuttings are used for some temperate zone fruit crops and not commonly used for subtropical/tropical fruit crops.

Propagation by cuttingsHardwood, semi-hardwood and soft-wood

• Semi-hardwood cuttings are taken from matured portions of the current season’s growth. In Florida, this type of growth is usually available, July through Sept.

Soft-wood cuttings are made from soft, new spring growth – it has some maturity but is flexible. In Florida, this type of growth is usually available, May and June and; again if plants repeatedly flush.

May be used for guava, citrus, etc.

Propagation by cuttingsHardwood, semi-hardwood and soft-wood

Procedure• Cut material with

leaves attached, place in plastic bag; bring to propagation area.

• Hint: the best time to collect material is early in the morning.

• Cuttings are between 4-8 inches long (1-3 nodes).

• Remove leaves from lower 1/3 of cutting. Leave 2-4 leaves or leave parts of leaves.

• Dip basal end of stem into rooting hormone.

• Strike (place) into rooting media and place 2 stakes into the into container to hold the plastic bag over the cuttings.

Propagation by cuttings

containerfilled withmedia

cuttings

stake

clearpolyethylenebag

tape/string

Propagation by cuttings

• Place struck cuttings in the shade.• Periodically open the bag and mist the cutting

with water.• Periodically inspect the cuttings for signs of

rooting.• Periodically water the soil media – but do not

over (constantly) water, as this may lead to rotting.

Propagation by suckers (off-shoots)

Banana – remove sword or peepers from base of mother plant. Swords may be planted immediately. Sword suckers may be planted or potted-up for later planting.

• This plant material should be disinfested for nematodes and fungal diseases.

• Pineapple – suckers arise near the base of the stem, leaves, or roots. Remove from parent plant, air-dry cut surface for 1-2 days in the shade, then plant in new location or pots.

Banana propagation by

suckers

sword sucker

peeper

Grafting and budding

• Refers to the process of joining parts of two separate plants in such a way that they will unite and grow on as a single plant.

• Scion refers to the part of the graft that produces the top of the new plant and ultimately the fruit.

• Rootstock refers to the part of the plan that forms the lower trunk and root system of the new plant.

• A rootstocks may be a seedling, cutting, layer, or offshoot.

Grafting and budding

The most important components for grafting and budding include:

• time of year; • compatibility among

the scion and rootstock material;

• budwood and/or rootstock preparation.

• Lining up the cambium tissues of the scion and rootstock so they bond.

• Preventing moisture loss from the scion during the healing/bonding process.

Grafting and budding

• Grafting involves the use of a scion with two or more buds.

• Budding involves the use of a scion with only one bud.

Grafting and budding – time of year

For subtropical/ tropical fruit crops this may be:

• During the spring or fall when it is slightly cooler (e.g., avocado);

• During warm weather (e.g., mango);

• When terminal or axillary buds are beginning to swell (e.g., mamey sapote).

• When rootstock and scion material are actively growing – the bark easily slips, i.e., bark can be pulled away from the wood without tearing (e.g., citrus).

• In subtropical temperature may be the deciding factor. In tropical areas rainfall may be the major factor.

Grafting and budding – compatibility among scion and rootstock

• Graft incompatibility is the failure of the scion/rootstock to “take” or survive indefinitely.

• The graft compatibility is greatest to least, within species > within genus. Most grafting/ budding is done within species.

• Symptoms of graft incompatibility include death of the graft or bud wood, wilting, dieback, and death of the scion and/or death of the rootstock.

• Incompatibility may be delayed by a short time or years after grafting.

Budwood preparationThe purpose of

budwood preparation is to force buds into active growth and/or increase the carbohydrate status of the scion wood.

• Actively growing buds of some species graft “better” than dormant buds.

Procedure• Remove the last 4-10

terminal leaves (the petiole remains) on a shoot several days or weeks prior and/or

• girdle the shoot 12-24 inches from the terminal from which budwood will be cut.

Rootstock preparation

• The purpose of rootstock preparation is to force the plant into active growth and/or to increase the carbohydrate accumulation of the rootstock or both.

Procedures/options• Cut-off the top of the

plant a day to several days ahead of grafting/ budding (e.g., mamey sapote, canistel).

Collection of budwood

• In general, cut only enough budwood for the day’s grafting needs. Scionwood of many tropicals does not store more than a few weeks.

• Select wood with matured axillary and/or terminal buds (these may or may not be prepared depending upon necessity).

• Commonly, scionwood is collected from the previous season’s growth or from the base of a new growth flush after it has matured, just as axillary buds begin to grow.

• Remove the leaves immediately, leaving a short stub of the petiole (leaf stalk).

Veneer grafting

• Use a young rootstock (RS) with lower branches and leaves removed.

Veneer grafting

•On the rootstock make a thin vertical cut, 2-3” long, with a second horizontal cut at a 45o angle at the bottom of the first cut.

side view front view

Veneer graftingscion withterminal bud(s)

scion withonly axillary buds

• Select a scion with 2-3 buds and of similar diameter as the rootstock.

Veneer grafting

•On the scion make a slanting cut on 1 side, equal in length to that on the RS. Make a small angled cut at the base to match the notch on the RS.

side view back view

Veneer grafting

• Set the scion in place on the RS making sure to line up the cambial layers on a least 1 side.

rootstock

scion

Veneer grafting

•Wrap the graft in an upward spiral, starting below the graft to just above the graft; tie-off the tape.

Cleft grafting

• Select a young RS and remove leaves near the area to be grafted; cut-off the top of the plant.

Cleft grafting

•Make a vertical cut 2-3 inches long down the center of the rootstock.

rootstockside view

top view

Cleft grafting

• Select a scion 4-6” long, preferably the same dia. as the RS.

• Make a 2-sided wedge at the base of the scion; the same length as the cut in the RS.

Cleft grafting

• Insert the scion and align the cambial layers on at least 1 side.

rootstock

scion

Cleft grafting

•Wrap the graft in an upward spiral with the last turn made to cover the cut ends of the RS; cover the entire graft with a polyethylene bag; place grafted plant in shade.

bag

Inverted T-budding

• Cut the scionwood bud by making a thin cut starting ¼” above the bud and ending ¼ below the bud; cut just under the bud so a thin sliver of wood remains under the bark of the bud (shield).

Inverted T-budding

• Use a young rootstock (RS) with lower branches and leaves removed.

Inverted T-budding

•On the rootstock, make a thin vertical cut just through the bark, 1-11/2” long in a smooth area of the bark.

Inverted T-budding

• Next, make a horizontal cut ½-3/4” long just through the bark that intersects the lower end of the vertical cut.

• Open up the two flaps of bark to reveal the cambium and wood.

Inverted T-budding

• Push the scion bud underneath the flaps on the RS so it completely encloses the bud.

Inverted T-budding

•Wrap the bud in a upward spiral, starting below the graft to just above the graft; tie-off the tape.

Aftercare of grafted/budded trees

• Grafted plants should be placed in a shaded area and/or mist area.

• Unwrap the graft when the scion has begun to grow (2-8 weeks).

• Remove plastic bags covering cleft graft/ rootstock.

• Forcing the graft to grow may speed up the process.

Forcing procedures

• Lopping• Bending• Topping Stake and tie the

scion after removal of the RS top; remove RS sprouts.

growing scion

rootstock

Forcing - topping

Forcing - bending then later removing

the original top

rootstock

growing scion

cord, string, grafting tape

rootstock

growing scion

Forcing – lopping, I.e., cutting part way through the rootstock then later

removing the original top

rootstock

growing scion

stake

Staking the new shoot

Newly grafted tree

• When removing (cutting) the seedling top back to the graft, be careful not to damage the graft union area.

• Care for the growing scion/rootstock plant so the graft union heals and the new scion takes over as the top of the new tree.

Grafting timing

• Avocado, fall/winter• Mango, late

spring/summer/fall• Carambola, late

spring/summer• Sapodilla, summer• Mamey sapote,

March-May, Oct.-Nov.

• Guava, late spring/summer

• Jackfruit, late spring/summer

• Canistel, summer• Sugar apple, seed,

3+ months old• Passion fruit, late

spring/summer

Credits• Author – Dr. Jonathan H. Crane,

Tropical Fruit Crops Specialist• Photographs – copyrighted

– Ian Maguire– Jonathan H. Crane

• Drawings – Jonathan H. Crane• This presentation is copyrighted,

2005 University of Florida, Institute of Food and Agricultural Sciences