Rapid Mass propagation Techniques of Cassava Planting Materials

for Nursery Establishment

Introduction

Cassava ( Manihot esculenta Crantz.) is the most important rootcrop in the

tropics and ranks fourth after rice, wheat and corn as calorie source for

human consumption. In the Philipines it is utilized as food, feed, alcohol and

the emerging biofuel industry.

In support to the country’s cassava industry, PhilRootcrops undertakes a

continuing crop improvement program to develop new and improved

varieties. There are 46 high yielding varieties recommended for cultivation

(2009).

The demand for cassava in the country is not met. This is mainly due to the

lack of planting materials of the high yielding varieties (HYVs) and the lack of

capability to mass propagate the HYVs. These varieties do not reach the

target clienteles because of slow and limited distribution of planting

materials.

Traditionally, cassava is propagated vegetatively using 15-30 cm cassava

stakes with 7-8 viable nodes. Multiplication rate 1:10; one stem cutting will

yield 10 planting materials after 10-12 months. Rapid propagation

techniques are already available. It is essential to develop skills and

capability for the mass propagation of cassava in order to sustain the supply

of HYVs planting materials for industry. The brochure will show the rapid

propagation techniques and production of clean planting materials for

cassava. 1

A. Production of 2-node Cuttings

1. Select physiological mature, pest-and disease-free cassava stems.

Cut from hardwood portion of the stems leaving at least 30 cm of

the plant standing from the ground.

2. Cut the stems into mini-stems containing two viable nodes using a hack

saw. Separate the hardwood or lower portion, the semi-mature or middle

parts cuttings and the tip-shoot mini-stem cuttings. Dip the mini-stems in

broad spectrum insecticides and fungicides to destroy the existing pests and

diseases of cassava materials.

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3. Pre-sprout the mini-stems in nursery beds or in perforated polyethylene

bags filled with good quality soil. Prepare a nursery bed 1 meter wide of any

convenient length under shade. Plant the two-node mini-stem horizontally

in a small furrow in the bed at very close spacing but the mini-stems must

not touch each other. Plant tip-shoot cuttings vertically and group them

together in the nursery bed. If the polyethylene bag is used, plant the node

cutting vertically position with two-thirds of the nodes buried in the soil.

Place the planted polyethylene bags in partial shades. Follow the steps for

nursery maintenance indicated below.

Mini stems planted in seedbed (A) and in polyethylene bag (B)

• Water the cuttings immediately after planting; and then either

in the morning or late in the afternoon until 2 weeks after

planting or when the plants have already established.

• Label the beds indicating the variety and planting date.

• Weed regularly to keep the nursery clean.

• Cover the cuttings that become exposed during watering

• Fertilized the plants with urea at the rate of 1.5 g/m2

Within one week after planting to ensure germination and

vigorous growth.

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A mature

cassava

plant ready for

production of 2

node cuttings

Segregate mini stems;

hardwood, middle

part and tip shoot

4. Mini-stem cuttings (especially hardwood and semi-mature) sprout about

7-10 days after planting. Fibrous roots develop at the nodes and the oldest

ends of the cuttings. Later, shoots emerge and develop leaves. Keep mini-

stem cuttings in the nursery for 4-6 weeks before transplanting in the field.

5. Transplant cuttings in a well prepared field at a spacing of 0.75 m-1 x 0-

5.75 m. Firm the soul around each plant. Label the plots indicating the

variety, date of planting and other important data.

Newly transplanted pre –sprouted 2 node cuttings in the field

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6. After transplanting, maintain the field in order to produce strong, healthy

plants. During the first 10 weeks, hoe to loose the soil and control weeds.

Apply fertilizer where necessary and as appropriate.

7. At 8 months after transplanting, cut the stems and distribute to farmers.

Do not uproot plants to harvest storage roots.

Eight-month old cassava plants

8. Cut the stems at a height of 30 cm above the ground. Be sure that the

stems are physiologically mature and free of pest and diseases.

9. Tie the stems together in bundles of desired number. Handle the stems

with care when harvesting, loading, transporting and unloading to avoid

bruising. Bruised buds may never develop into shoots.

Bundled cassava stems ready for distribution

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10. Cassava cuttings cannot be stored for a long time because stems

dehydrate. Storage can only be up to 8 weeks. When storing, place the

stalks in an upright position (bud facing up) in a well ventilated shed or

under a tree providing good shade.

Other information

Cassava yield using two-node cassava cuttings and traditional sets is

comparable.

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The practice of leaving stumps standing after cutting the stem is known as

“ratooning”. Several shoots may sprout from each stump, but leave only

three or four shoots. Apply fertilizer to the rationed fields.

The rationed field 2 months after cutting the stem

Cut another set of stems again 6 months later. Harvesting of stems

could be up to three times.

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B. Tissue Culture

Stage 1111 Donor Plant Established and Explants Isolation

• Plant cassava stems cuttings in pots with sterilized soil and maintain

under the screen house. Water the plants regularly and spray

fungicides twice a week using the recommended rate. Apply

insecticides if necessary. Harvest sprouts with 4-5 nodes from the

tip.

Newly harvested cassava sprouts (A),

Disinfecting solutions (B)

• Remove the expanded leaves and petioles of the sprouts. Wash

with tap water, soak in 2 % NaOCI for 5 minutes. Rinse the tissues

with sterile distilled water three times inside the sterile chamber.

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Stage 2222 In Vitro Stockhouse Establishment

• Prepare modified Murashige and Skoog (1962) culture medium and

sterilize using autoclave / pressure cooker for 15 minutes at 15 psi.

Preparation of explants in the sterile chamber (A), Cultures maintain in

incubation shelves (B)

Isolate single nodal explants inside the sterile chamber and inoculate

immediately into a culture medium. Maintain the cultures in shelves

illuminated with fluorescent tubes. The room temperature must be

maintained at 25 + 2° C.

In Vitro stock plants at different growth stages

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Newly established

cassava plants in

the screenhouse

A- 1 week old

B- 2 week old

C-3 weeks old

Stage 3333 Micropropagation

• After 1 month of incubation, 3-4 in vitro nodal stock plants are

ready to sub-culture using single nodal explants.

• Complete plantlets are ready for plotting out after about a month

from inoculation.

Stage 4 Potting-out and Field Maintenance

• Transfer the cultures to ambient room condition for about a week

before potting

• Transplant the plantlets in bottles to pots or plastic bag with sterile

soil medium and place in the greenhouse for 3-4 weeks for

hardening stage.

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• Plant the hardened cassava in the field at least 1 month after

potting out. Follow the proper cultural management practices.

Comparison of the size of the traditional planting

materials (A) and the first cycle tissue cultured

derived planting materials planting materials (B)

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Micropropagated

Cassava nodal

explants

Cassava plantlets potted for

hardening in the

screenhouse

Hardened cassava

plantlets ready for yield

transplanting

• Yield in weight and number of storage roots in tissue cultured-

derived planting materials was higher in the genotypes studied.

Cassava Genotypres

Graphical presentation of the comparison between the tissue culture-derived

planting materials and the traditional practice. Data reflected is for first

cycle evaluation only.

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Sources of Information and Pictures

Centro Internacional dala Agricultura Tropical

(CIAT) Thailand and Cali, Colombia

Center for tropical Crops Research Institute

(CTCRI) Trivandrum, India

Philippine Root crop Research and

Training center (PhilRootcrops)

Visayas State University, Visca,

Baybay City, Leyte, Philippines

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