2013. ceballos. new and better cassava varieties

How to get high and stable yields in cassava?

New and better varieties

Hernán Ceballos

2nd Starch World 2013Jakarta, Indonesia

(February 2014)

How to get high and stable yields in cassava?

Use improved,high-yielding

varieties

How to manage the problem of diseases in cassava?

The “corner of prosperity”

Let the genetic potential show

The varieties of the future

Climate chage

El “Rincón de la Fortuna”The “Corner of Prosperity”

A good variety is not enough to have high andstable yields

The objective of most cassava breeding is toproduce varieties that can efficiently take advantage of whatever the environment canoffer to them

The best racing car still needs gasoline for winning a race…

High-yielding variety +

Good quality planting material

El “Rincón de la Fortuna”The “Corner of Prosperity”





Climate chage

The story behind the Green Revolution

Poor

conditionsIntermediate

conditionsOptimum

environment

Yiel

d (t/

ha)

Traditional varietiesImproved varieties

Adequate inputs

Maximumresponse

The story behind the Green Revolution

Improved varieties have tolerance or resistance to bioticor/and abiotic stresses that make them more resilient

However, under sub-optimal conditions there is little that improved varieties can make to benefit farmers

As environmental conditions improve, new varieties can develop their full potential

Cassava is a humble crop that responds generously to the smallest of inputs

Multiple nutrient (NPK) deficiencies Without and with balanced N, P and K

Poor germination in quartz sand soil..

……due to severe Zn deficiency

Very acid and low fertility soils

Source: Reinhardt HOWELER

Soil is alkaline resulting in micro-nutrient deficiencies

Fe deficiency Zn deficiency

Mn deficiency After micro-nutrient foliar spraySource: Reinhardt HOWELER

This map could be used to indicate strength of markets for cassava

Strong markets lead to adoption of technologies which reduce yieldgap. “The best agronomist is a good price for cassava…”

Impact, in other words, depend on the strength of markets.

Increasing demand and insufficient supply of cassava is pushing up prices of dry chips, starch and ethanol, making these less

competitive in world markets

5

10

15

20

71-73 77-79 83-85 89-91 95-97 01-03 07-09Three years period

Africa

LAC

Thailand

Asia

VietNam

Evolution of cassava yields (t/ha) in the last 40 years





Climate chage

What makes a good variety good?Optimum leaf area (not too much, not too little). Not affected by diseasesGood production of planting material, stems can be storedfor long periods, rapid andvigorous sprouting

High starch content in the roots

“Hungry” roots: always wantmore starch from the top

Golden Yellow

KU 50: better plant type and higher yield


Herbicide tolerance

Cassava is a weak competitor, and its growth and yield are seriously reduced by weed

competition

Varieties that are tolerant to herbicidesmake weed control more efficient and less expensive

Varieties that are tolerant to herbicidesmake weed control more efficient and less expensive

Ongoing project to develop herbicide-tolerant cassava (The Bill & Melinda Gates Foundation) by: Genetic transformation Targeted mutations Random mutations

CIAT is searching for “natural tolerance” in the germplasm collection

Golden Yellow



New plant type

0

2

4

6

8

Ave

rage

yie

ld (t

/ha)

1875 1895 1915 1935 1955 1975 1995

Year

Open pollinated varieties

Doubled cross hybrids(from 4 inbred parents)

Single cross hybrids(from 2 inbred parents)

0

2

4

6

8

Ave

rage

yie

ld (t

/ha)

1875 1895 1915 1935 1955 1975 19950

2

4

6

8

Ave

rage

yie

ld (t

/ha)

1875 1895 1915 1935 1955 1975 1995

Year

Open pollinated varieties

Doubled cross hybrids(from 4 inbred parents)

Single cross hybrids(from 2 inbred parents)

Evolution of maize yields in the last century

How was this achieved? What changed in all those years?

All this progress can be summarizedin just one characteristic:the ability of maize to grow (and produce) in “crowded” conditions

In 1950 maize was planted at 40K plants/ha,today at more than 100K plants/ha.The plant architecture had to change…

A trial currently in the field evaluating four clones at: 10,000 pl/ha 22,000 pl/ha 36,000 pl/ha 42,000 pl/ha

Cassava in Asia is usually grown on small farms, ranging in size from 0.2 to

4.0 ha

The land is prepared either by hand, with oxen, small hand-tractor or 4-wheel tractor

However, lack of labor will soon require mechanized production

New varieties need to be suitable for mechanical: Planting Harvest of the stems Harvest of the roots Harvest of the foliage

Golden Yellow



Cold tolerance

Cold tolerance for cassava at high latitudes

Cold tolerance would increase productivity of cassava grown at high latitudes

…and expand the the frontiers of cassava cultivation

Golden Yellow


Manihotsfrom

Argentina

Golden Yellow


M. Grahami and M. anysophyllagrow wild in the mountains of Cordoba province (my home !!!)

These are latitudes as high as32°40´ and around 1000 masl

In these regions it snows every year and minimum temperatures can range from -5° y -9°

Plant type is very similar to cassava. These particular populations may be ideal for introgressing tolerance to low temperatures in cassava for China, Vietnam, Laos and Myanmar

Golden Yellow



New starches

Golden Yellow


New starches

Cassava is the second most important source of starches in the world (after maize)

It has two important advantages: a competitive price and excellent quality

However, cassava starch industry has a disadvantage as only “generic” type of cassava exists in the market

The identification of new starches with different functional properties and new industrial applications would make cassava starch even more competitive

Golden Yellow


New starchesDr. Peng Zhang (National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai)

Peng´s team is conducting very interesting work to produce genetically modified (transgenic) cassava whose starches have different functional properties

New starches: waxy starch

In 2006 a natural mutation of waxy (amylose-free) starchwas discovered at CIAT

In 2014 the first commercial waxy-starch variety will be

released in Thailand Thai Tapioca Development Institute (TTDI) & Kasetsart University

New starches: ethanol and sweeteners

Small-granules

8.77 μm

5.73 μm

7.95 μm

9.69 μmAM 1295-14 (42.4%)

AM 206-5

MTAI 8 (Rayong 60)

MCOL 1505

Original mutation (32-36%)

Normal granule size cassava starches

Similar results using Stargen 2 commercial enzyme

Other small granule starches

New starches: double mutantsDouble mutants Small granulesWaxy

New starches: resistant starches

The work carried out by Peng´s team in Shanghai and our own work will help determine what kind of genes need to be mutated for cassava starch to be less digestible

Knowing what are the target genes CIAT will be able to applymolecular technologies (such as TILLING) to screen the large germplasm collection in search of natural variants

We are also continuing the normalscreening of starches and will alsostart a new mutation breeding process

(for diabetic and overweight people)





Climate chage

20 meters

FACE (Free-air concentration enrichment) RINGS

Source: D.R. Ort et al. (USDA-Univ. of Illinois)

Inside the ring, plants grow with CO2 concentrationssimilar to those predicted for year 2050 (≈ 500 ppm)

Photosinthesis and yields in C3 crops (e.g. soybean, cassava, rice) improve with increases of CO2 in the air

Source: Long, Ainsworth, Leakey, Nosberger, Ort (2006) Science 312, 1918-21

Cassava response to “[CO2] fertilization”

Higher biomassHigher harvest indexIncreases in leaf area indexMore storage rootsHeavier rootsRUBISCO deregulationNo change in cyanogenic glucosides

These benefits increase further when day and nighttemperatures increased by 5 °C

Sources: D.R. Ort et al. (USDA-Univ. of Illinois)Imai, Coleman, Yanagisawa, Japan. Joun. Crop Sci. 53:479-485 (1984)

However increases in the performance of C3 crops fall short of expected benefits from“[CO2] fertilization”

Daily carbon fixation

Source: Long, Ainsworth, Leakey, Nosberger, Ort (2006) Science 312, 1918-21

The information presented shows a promising future for cassava

Many institutions are working to make cassava more competitive

Thank you for your attention

Contacts:[email protected]@cgiar.org