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Home , Cassava, Tropical horticulture

Cassava Cassava Domesticated species Tropical No wild progenitors known

Manioc Mandioca Yuca esculenta

Cassava Cassava

Domesticated Domesticated species species  “” of the – Perennial lowland – 1-4 m tall – Starchy root – Enlarged root • 30-40% – Leaves edible • 30%

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Two Centers of Distribution of Cassava

Bitter Cassava and Northern

Mid 1800s Sweet Cassava s Central America 600 ly 1 Ear Early 1800s

Dietary staple when Late 1700s Spanish arrived

Early 1600s

Tropical Horticulture - Texas A&M University Tropical Horticulture - Texas A&M University Adaptation of Cassava Cassava is Adapted to the Tropical to subtropical Lowland Tropics – No freezes – Minimum annual mean temperature “Potato” of the Lowland Tropics • 17°C to 20°C (63°F to 68°F) Rainfall – 1000 to 1500 mm – Sensitive to waterlogging – Tolerant of Tropical Horticulture - Texas A&M University

Adaptation of Cassava Adaptation of Cassava

Acid soils of low Harvest date flexible fertility – 6 to 36 months  Efficient at extracting – Harvest as need Tolerant to foliage loss  Mycorrhizal associations – Insect or disease attack  Sensitive to – Drought or storms – Saline – Calcareous - high pH Subsistence crop – Waterlogging

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Cassava Production by Region Cassava Production by Region (million mt) Region Greater than 5 to 15 1 to 5 Region Production 15 1,000s mt Malawi Africa 99,195 53% Congo Tanzania Asia 54,923 30% Guinea Asia India Vietnam Americas 31,770 17% Americas Brazil

FAOSTAT, 2003 FAOSTAT, 2003 Tropical Horticulture - Texas A&M University Tropical Horticulture - Texas A&M University Cassava Production in the World Cassava Production and Yield FAOSTAT, 2003 Region Production Yield 1,000s mt mt/ha Africa 99,195 8.9

Asia 54,923 14.7

Americas 31,770 12.6

FAOSTAT, 2003 >15 million mt 5 to 15 million mt 1 to 5 million mt Tropical Horticulture - Texas A&M University Tropical Horticulture - Texas A&M University

Why low yield in Africa? Cassava Most in sub is an Important Source of Sahara region and grown dryland Calories Soil fertility in the Tropics – P and K Cassava mosaic A for Millions of People

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Staple as sources of calories (billion kcal/day) Importance of Cassava Crop Tropics World 924 2043 Dietary source of calories 307 600 – 4th in tropics after rice, , and Sugar 311 926 maize Cassava 172 178 Sorghum 147 208 Primarily as food <100 1877 – 60-70% Potato 54 434 Musa 62 74 – Equally cooked fresh and processed 30 208

Source: FAO, Food balance sheets, 1975-1977 average, Rome, 1980 Tropical Horticulture - Texas A&M University Tropical Horticulture - Texas A&M University Cassava as Food Preparation

Fresh root Cooked, boiled, roasted, fried Sundried Detoxication by solution – Soaking, Boiling, etc. Detoxication by fermentation

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20-30% as Feed Cassava for industrial use Varies by region – Southeast Asia 10% for industrial starch • 4% (also export) – Africa • 6% – Americas • 57% Also exported to developed countries • 30% of cassava used for feed Tropical Horticulture - Texas A&M University Tropical Horticulture - Texas A&M University

Nutritional value of cassava Cassava as a Food

1 kg cassava RDA Excellent source of calories 347 gm  are a poor protein source Calories 1,460 2,500 – Leaves can be eaten and are good protein Protein 12 g 46 g source 3 g Significant source of Ca 330 mg 500 mg – Calcium and Iron 7 mg 8 mg – C 360 mg 25 mg

Tropical Horticulture - Texas A&M University Tropical Horticulture - Texas A&M University Toxicity Mechanism of Toxicity

Breaking cells Detoxification of in blood – converted to hydrocyanic acid – Requires S Acute toxicity, death Thus body needs more S-containing – Rare, only if eat raw amino acids Chronic toxicity – Essential for development of nervous system – Nervous system degeneration Also interferes with iodine uptake of – Goiter thyroid

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Chronic Toxicity

Nervous system degeneration Goiter Cassava Production Only where – 1 kg or more of fresh cassava roots consumed daily over extended period – Consumption of animal protein low – Consumption of iodine low

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Farm Characteristics Propagation

Most of cassava in world Stem cuttings – Grown under adverse – Mature plant • Climatological conditions – 10-30 cm (4- • Soil conditions 12”) long – On farms that are – > 3 nodes • Small • Poor • Marginal areas

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During root harvest – Harvest stem cuttings for planting of next crop Cut stems into appropriate size in field

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Propagation Planting material

Storage of stem Good quality planting material essential cuttings – Minimum of 3 nodes – Bundle as meter – Can increase yields up to 70% long stems • Basal end in soil • 4-6 months – Southern Brazil • Cool winters • Underground shelter or trench

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Planting material Planting

 Discard cuttings with  Density (/ha) insect or disease – 7,000 to 20,000  Use pre plant dip of  Position planting material – Vertical to horizontal – – 5-10 cm deep – Insecticide – Higher population w/ low fertility or poor – sulfate, zinc deficiency very  Plant beginning of wet season common

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Does Cassava DEPLETE the 20 20 18 18 soil of nutrients? 16 15 14 13 kg/ton dry 12 matter 10 10 harvested 8 6 6 4 2 0 Cassava Potato Maize Rice Sorghum Wheat

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Phosphorous Extraction Potassium Extraction

4 25 22 20 3

kg/ton dry kg/ton dry 15 matter 2 matter 11 harvested harvested 10

1 6 6 5 4 4

0 0 Cassava Potato Maize Rice Sorghum Wheat Cassava Potato Maize Rice Sorghum Wheat

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Cassava is well adapted to lowland Calcium Extraction tropical soils

2 Tolerant of

1.6 1.6 – Low fertility soils – Acid soils kg/ton dry matter 1 – High aluminum levels harvested 0.8 0.6 0.5 0.5 Respond well to fertilizer applications – Low requirement for N 0 – High requirement for P and K Cassava Potato Maize Rice Sorghum Wheat

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Not more than other crops Newly planted cassava grows slowly – Able to extract nutrients from soils of low – Critical to control the first 3-4 months when fertility - mycorrhizal associations it is establishing – Produce better under low fertility than other Hand weeding crops – Most common Adjust top growth to fertility present so – 2 to 6 weedings only show symptoms in extreme cases  - normally with some hand weeding

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High density and Weed Control and Weed Control

Planting Density Level of Weed Control 25 30 Low Good 20 High 25 High None 20 Good 15 None Low 15 10 10 Yield MT/ha Yield MT/ha 5 5 0 0 None Good Alone With Bean Level of Weed Control Tropical Horticulture - Texas A&M University Tropical Horticulture - Texas A&M University

Cassava intercropped with legumes - Cassava intercropped with grain legumes - Thailand India

Cassava alone Cassava alone – 27.6 t/ha – 24.8 t/ha Cassava with Cassava with – 26.7 t/ha (97%) and 0.7 t/ha soybeans – 16.6 t/ha (67%) and 2 t/ha cowpeas Cassava with peanuts Cassava with peanuts – 24.6 t/ha (89%) and 0.9 t/ha peanuts – 19.7 t/ha (79%) and 0.6 t/ha peanuts

Tropical Horticulture - Texas A&M University Tropical Horticulture - Texas A&M University Cassava intercropped with grain legumes - Costa Rica Advantages of Intercropping Weed, pest, and disease suppression Cassava alone – 16.8 t/ha Nutritional complementation – Combine starch with protein crops Cassava with dry beans – 15.2 t/ha (90%) and 1.5 t/ha dry beans Legumes fix nitrogen Yield per land area usually greater Early return on investment – Grain legumes harvest after 2-4 months – Cassava after 9-24 months

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Is Cassava Pest Proof? Distribution of Cassava Pests

Tolerant of loss of foliage Pest Asia Africa Americas – Loses part of yield but not all Thrips XXX XXX Mites XXX XXX XXX No critical stage for yield formation Hornworm XXX XXX XXX XXX – when stressed at certain stages lose Grasshoppers XXX all yield XXX XXX Scales XXX XXX XXX There are diseases that kill plant - these will eliminate yield

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Mite Damage Hornworm Damage

 Outbreaks during dry  Defoliate the plants season – 20% yield loss per – Up to 50% loss attack  Protection  Protection – Resistance – Biological – Biological • Wasp predators • Wasp houses in fields • Predator mites • Ladybugs • Beetle larva • Lacewings

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Feed on young leaves Feed on cells in stems – Reduce leaf area – Debilitate plant – 30% yield loss – Reduce stand if on stem Protection cuttings – Resistance Protection – Insecticide dip of stem cuttings – Biological control

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Whitefly Damage Defoliation by other pests Defoliation causes a 20% yield loss Feed on cells in leaves – Debilitate plant – Yield loss of 80% Protection – Resistance

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Distribution of Cassava Diseases Superelongation

Disease Asia Africa Americas  Fungal disease – Only in Bacterial blight XXX XXX XXX Americas – 100% yield loss Superelongation XXX  Protection – Resistance Frogskin XXX – Treatment of stem cuttings Cercospora XXX XXX XXX

Cassava Mosaic XXX XXX

Tropical Horticulture - Texas A&M University Tropical Horticulture - Texas A&M University Cassava Bacterial Blight African Mosaic Virus

 Bacterial disease  Virus – Widespread – vector – 100% yield loss – Africa and India  Protection – Up to 90% yield loss – Resistance – Certification of  Protection health of stem – Resistance cuttings – Rogueing – Certification of health of stem cuttings

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Pests and Diseases of Cassava Harvest

 Tolerant of foliage loss  Flexible harvest – Most insects and disease time  Complete loss if disease/pest – Stores well in – Systemically infects plant ground – Kills plant – 6 to 24 months  Control mainly based • Fresh, 6-15 mo • Industrial, 18-24 mo – Biological control – Quality lower if – Resistance harvest late  Low value crop so application not usually economical Tropical Horticulture - Texas A&M University Tropical Horticulture - Texas A&M University

Harvest Harvest

 Harvest by hand  Harvest by hand – Cut off at 30 cm – Cut off at 30 cm – Pull/dig – Pull/dig – Cut off roots – Cut off roots  Harvest aids  Harvest aids – Chain/pole lever – Chain/pole lever – Tractor mounted – Tractor mounted digger digger

Tropical Horticulture - Texas A&M University Tropical Horticulture - Texas A&M University Lowland Tropics Cassava Production Zones Most important production zone  Dry season - 50% of production Lowland Tropics: Mean temp > 22C – 800-2000 mm, 3-6 month dry season – Dry season – Light, acid soils of low fertility – Humid  Humid – Acid, infertile savannas – 1500+ mm rain, well distributed Highland Tropics: Mean temp 17-22C  Acid, infertile savannas , Warm summer, cool winter – 3-6 month dry season – Very acid, infertile soils – Underutilized lands

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Cooler Zones

Highland Tropics (1500 to 2300 m) Selecting – Well distributed rain variety – No freezes adapted Subtropical Zones to zone is – Most rain during summer critical – Cool winter/hot summer

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Potential Yields with Maximum Yields of Crops Management Crop Max./yr. Kcal/ha/day Lowland tropics (10 - 12 months) Cassava 71 t/ha 250 – Good fertility 30 - 35+ t/ha Maize 20 t/ha 200 – Mod. fertility 25 - 35 t/ha – Acid infertile 15 - 25 t/ha Sw. potato 65 t/ha 180 Highland tropics (14 - 18 months) Rice 26 t/ha 176 – Mod. fertility 20 - 30 t/ha Wheat 12 t/ha 110 Subtropics (10 - 20 months)  39 t/ha 80 – Mod. fertility 20 - 40 t/ha

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Dried/processed cassava products Fresh roots – Cheap source of calories – Consumed within a week of harvest – Income increase, use decrease Storage Fresh cassava – High humidity & fungicide, 2-3 weeks – Rural areas, cheap calorie source – Refrigeration, not readily available – Urban area, often a luxury item – Freezing, very expensive Novel uses Dried products – Bread, HFS, feed, protein source

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