Redesigning cassava for tomorrow's demands Asia Clair Hershey

Redesigning Cassava for Tomorrow’s Demands

Global trends for world’s most important food crops

Change in 30 years, to 2009 (%)

Production Harvested area

Yield

Cassava 101 44 40Maize 95 29 52Rice 81 14 60Wheat 61 -1 63Millet 32 -5 39Potato 10 -5 12Barley -3 -35 48Sorghum -5 -1 -4Sweet potato -22 -27 6Oats -45 -60 37

Source: FAOSTAT 2012

.

• Low soil fertility• Drought-prone areas• Sloped lands• Low access to roads and markets• Product options limited in many areas

Typical Agro- and Market Environment for Cassava

But the crop also can respond to good management to produce very high yields

Cassava for modern times

Challenges• Uncertainties of climate change• Soil fertility maintenance and erosion control• Pest and disease management• Production systems for clean planting material• Trait development tailored to new markets

Opportunities• Resilience in multiple environments• Diverse new market options• Under-exploited genetic diversity

Is cassava the answer for climate change adaptation?

Based on the EcoCrop model: Cassava will respond positively in many current regions of planting

Ceballos et al. 2011Jarvis et al. in press

More than 6,000 accessions plus 1000 acessions of 30 wild species

The genebank:Our main source of genetic variability

Frequency of major cassava pests across continents

Pest category Americas Africa Asia Whiteflies 11 3 3Mealybugs 6 3 6Root mealybugs 2 2 0Mites 30 13 15Scale insects 8 7 3White grubs 6 3 5Termites 2 2 1Thrips 5 1 5Leafhoppers 3 0 0Grasshoppers 2 4 0Shootflies 3 0 0Stemborers 12 4 3Lacebugs 4 0 0Burrower bugs 3 0 0Hornworm 2 0 0Tiger moth 2 0 0Army worm 3 0 0Gall midge 1 0 0Dried cassava 5 6 6

Total 110 48 47

Challenges and risks of intensifying cassava production

Bacterial Blight in southern Brazil: results of poorly planned rapid scale-up

Low intensity, stable traditional production

Preparing for new challengesof biotic constraints

Climate change models suggest that the greatest impact on cassava will be from biotic constraints, and much less from abiotic (drought; higher temperatures)

A recent example of new pest introduction

Cassava Mealybug in Thailand, March 2010

Anagyrus lopezi

Identification and characterizationMonitoring of spread and impactTraining 14 Asian scientists

Implementation and validation of management strategiesKit development for on-farm detection

Asia: Cassava Witches’ broom

CIAT Roles1. RISK ASSESSMENT: Lead a global assessment of

threats from cassava pests2. SURVEILLANCE: Establish comprehensive

surveillance and monitoring with national and international partners

3. MANAGEMENT: Establish or strengthen core capacities to meet global pest management needs

4. CAPACITY BUILDING: sustainable capacity to respond to pest challenges

• Amylose-free (waxy): multiple food and industrial applications

• Small granule starch: rapid hydrolysis for ethanol industry

• High β-carotene: for Vitamin A deficit areas

• Forage varieties: adding an animal component into small-holder systems

Value-added traits for new markets

Source

Storage stability (4°C)

Freeze/thaw stability(18°C) Clarity Taste

Maize * * * CerealRice *** * * CerealPotato * * *** NoneCassava *** ** ** NoneWaxy maize *** ** ** CerealWaxy Rice *** *** * CerealWaxy Potato ** ** *** NoneWaxy Cassava *** *** *** None

• = low acceptability** = medium acceptability*** = high acceptability

Source: Sánchez T., Dufour D., Moreno I. X., Ceballos H. (2010). Comparison of Pasting and Gel Stabilities of Waxy and Normal Starches from Potato, Maize, and Rice with Those of a Novel Waxy Cassava Starch under Thermal, Chemical, and Mechanical Stress. Journal of agricultural and food chemistry, 58, 5093–5099. http://dx.doi.org/10.1021/jf1001606

Some characteristics of cassava starch important for the food industry

Introduction of an animal component into smallholder systems is one of the best ways to

improve household nutritional status

• Direct feeding of surplus root production• Feeding of leaves and young stems• Feeding of residues of processing (peels, fiber, starch

residues)

Progress in breeding for total carotenoids content (A nutritional goal of 15 µg/g established in 2005)

Progress in breeding for total carotenoids content (A nutritional goal of 15 µg/g established in 2005)

TCC

(µg/

g)

0

5

10

15

20

25

30

2005 2006 2007 2008 2009 2010

Minimum

Average

Maximum

Year

y = 2.346x + 8.6995R2 = 0.7763

Some current projects in molecular analysis

High b-Carotene Whitefly resistanceTolerance to post-harvest deterioration

Drought tolerance

Summary: Cassava’s Redesigno Transition from low-value commodity crop to diverse and higher level

value chainso Protect the crop from the current biotic threats trans-boundary movemento High yielding and high quality varietieso Management systems to reduce production costs (e.g. labor use)o Integrate molecular and traditional breeding approacheso Adapt to climate change (pests and diseases, practices to conserve soil

water)o Policies and systems that provide better income while protecting the

environment

Train a new generation of scientists!

Working together for a New Future for cassava

growers in Asia -- through a growing interdisciplinary team in Hanoi with close

linkages to CIAT-Colombia

CIAT: Science to Cultivate Change

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