Clair Hershey

Cassava at CIATAnnual Program Review 2011

Nairobi, Kenya 10 May 2011

Starches

Hidrolisis

Waxy cassava starch granules (AM206-5)

Small granule cassava starch (5 G160-13)

0 20 40 60 80 100 120 1400.00

2.00

4.00

6.00

8.00

10.00

12.00

Time (hours)

Glu

cose

(%g/

g)

Highest rate of hydrolysis for Small Granule Cassava Lesser use of enzyme for same rate of hydrolysis

Waxy cassava starch

Normal cassava starch

Glucose content during Simultaneous Saccharification & Fermentation (SSF) of Very High Gravity (VHG)

cassava starch for ethanol production

Enzyme: Stargen 2; Genencor

Development of double mutants to generate new starch phenotypes

Waxy starch (wxwxSGSG) Small Granule WxWx sgsgX

F1 (Wxwx SGsg)

Self-pollinated or crossed

Wx -- SG--(Normal starch)

wx wx SG--(Waxy starch)

Wx -- sgsg(Small granule)

wx wx sg sg(Double mutant)

784 S1 and 188 “F2”, transplanted at the end of 2010, will be harvested and tested by the end of 2011

Progress increasing carotenoids content

Progress in total carotenoids content in cassava roots during the last six years of breeding

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

Relevant results from the evaluations made in 2010

DMC Total carotenoids

Total β-carotene

All trans β-carotene

Count 472 491 491 491

Max 46.70 24.70 19.14 16.51

Min 20.15 1.63 1.49 0.90

Average 30.19 11.56 9.89 8.20

St. Dev 5.25 3.42 2.74 2.59

Numberof

genotypes

≥10.0 ug 340 231 100

≥12.5 ug 172 68 22

≥15.0 ug 57 13 4

≥17.5 ug 17 4 0

Nutritional goal of 15 ug established in 2005achieved through a rapid cycling scheme

New tools

y = 2.4242x - 1.7686R2 = 0.6247

-20

-10

0

10

20

30

40

50

2 6 10 14 18

All trans β-carotene

Sele

ction

inde

x

The use of colorimeter (based on 478 observations) for quantifying β-carotene: combining the two relevant parameters in a selection index: (a – (h2*10)

Tolerance to PPD and/or training

First evaluation of post-harvest physiological deterioration in Thailand (Huey Bong)

1. Training on the procedure

2. Introduction of potential sources of tolerance

Gender issues

Most women in Africa are involved in weeding cassava fields (typically for the first two months of the crop)Tolerance to herbicides could have a positive impact on the lives of these women. We are focusing on this trait Women in Africa and LAC are involved in peeling cassava for small processing facilities (i.e. gari,farinha, etc.)Thick peels facilitate peeling, but is undesirable for starch extraction

The article “Genetic variability of root peel thickness and its influence in extractable starch from cassava (Manihot esculenta Crantz) roots” to be published in Plant Breeding adress this issue

Better understanding of cassavareproductive biology

New research on reproductive biology of cassava is required for the doubled

haploids project Germination of pollen and definition of time required by the pollen tube to reach the micropyle of the ovule

Stages of “normal” embryo sac development through the first four weeks after pollination

Definition of timing of stigma viability (before or after optimum timing)Pollination of female cassava flowers with castor pollen for the production of (doubled) haploid seeds

Methodology to analyze the growth of pollen tube in un-pollinated female flowers (a-b); one hour after pollination (c-d) and three hours after pollination (e-f)

P: pollen grain; PT: pollen tube

Illustrations of the kind of

preparationsmade to

understand the

developmentof the embryo sac in cassava

Training

Lisette Natalia Ramos (Ph.D. student, wide crosses)

Colored root segregation pattern in an advance breeding family

17 μg

0 μg

Plant Resources

Advance breeding family CM8996 for WFR

MEcu72MCol2246

MCol2246Susceptible

MEcu 72Resistant

Plant Resources

Genetic and Genomics - MASIPP

Geranylgeranyl diphosphate

Phytoene

Lycopene

-carotene(vitamin A precursor)

Phytoene synthase

Phytoene desaturase

Lycopene-beta-cyclase

ξ-carotene desaturase

-Carotene Pathway in Plants

Genetic and Genomics - MAS

• Cassava SSRs were Silver stained

• These SSRs are expensive & time consuming to perform

A M 3 2 0

TAI8 BW BY 3 7 8 10 12 13 14 15 16 17 18 19 20 21 22 23 25 26 27 29 30 31 33 35 36 37 38 39 41 42 43 44 45 47 48 49 51

C o l o r 4 2 8 4 8 5 4 2 2 2 8 5 8 2 5 2 4 5 1 1 2 8 4 8 8 4 8 1 5 2 4 4 1 8 3 3 3 4 3 8

Genetic and Genomics - MAS

• Electronic data capturing and analysis

96 or 384 well-plates

A B

B

B

B

B

A

A

A

6100

3-1-

002

6100

3-1-

003c

6100

3-1-

004

6100

3-1-

005

6100

3-1-

006

6100

3-1-

007

6100

3-1-

008

6100

3-1-

009

6100

3-1-

010

6100

3-1-

011

6100

3-1-

012

6100

3-1-

014

6100

3-1-

016c

6100

3-1-

017

6100

3-1-

018

BNL3989 H B H H H B H X H H H B H H HBNL1160 A B H H H B B H A H H H H A HBNL3895a A C A C C C A A A A C C A A CBNL3895b B D B B D B B B B B D D B B DBNL3806 B H X B X X X B X X B H B X BBNL0834a H H A X B H H H H H A A B A HBNL0834b D D D X B D D D D D D D D D BBNL0252 B A A H H A B B A A H H H B BBNL3811 H H H A B A H H A B A A B A ABNL0358 H H B H A H H H H H H B A H B

Previously developed genetic maps

Genetic and Genomics - MAS

• SNP discovery by genome RESCANing

10%

90%Non- repetitive

Repetitive

RRG

N N N N N N

Non-Illumina Adapter

Barcode

Illumina Adapter

N N N N N N

Barcode

Combine at least 48 genotypes per sequencing lane

~2-3X coverage

BREAD: Extending Unisexuality and Heterosis to Cosexual Cereal Crops

Processes and time-frame for developing breeder ready tools