advances in breeding and genetics to improve carotenoids content in cassava roots. international...
TRANSCRIPT
Advances in breeding and genetics to improve carotenoids
content in cassava roots.
International Center for Tropical Agriculture(CIAT). Cali, Colombia
Why Cassava
• A basic staple where both poverty and malnutrition are widespread
• 70 million people rely on cassava for basic sustenance.
• Cassava grows in poor marginal soils, where other crops will fail.
Why CIAT
• Located in the center of diversity for the crop: access to in situ germplasm.
• Holds the largest ex-situ cassava germplasm collection >6,000 accessions.
• Well-established cassava breeding and genetics programs, and supporting lab facilities.
Sampling and processing protocols
Pre-selection based on NIRS
Genetics of carotenoids
Genetic progress
Next steps: the pathway to impact
Two challenges of root sampling and processing procedures for carotenoids:
a) Variation among roots from the same plant and/or roots from different plants within the same genotype (Ortiz et al., 2011).
b) In some cases a drastic variation in levels of pigmentation within a root (following slides).
This section describes solutions that have been implemented to overcome some of the problems listed above, and alternative approaches to quantify carotenoids in fresh roots of cassava.
Some key background work on protocols:
Variation of levels of pigmentation within the root
Variation of levels of pigmentation within the root
Source: Peter Kulakow (IITA)
Addressing the issue of root to root variation
Former standard procedure: only one root per plant was taken
Beginning in 2011: three roots per plant used in carotenoids quantification.
Uniform homogenized subsamples taken as follows:
a. Two capsules for Near Infrared Spectroscopy (NIRs) screeningb. Two samples (≈ 80g and 30g) for dry matter content estimationc. One sample (≈ 100g) for chromameter readingd. One sample (5g) for carotenoid extraction and quantification in spectrophotometer and HPLC
Food processor used to grind the roots rather than chopping them
Examples of the texture in ground root samples
Root sample ground, not chopped
Minolta Chromameter CR 410
Sampling and processing protocols
Analysis & pre-selection based on NIRS
Genetics of carotenoids
Genetic progress
Next steps: the pathway to impact
Minutes0 2 4 6 8 10 12 14 16 18 20 22 24
Minutes0 2 4 6 8 10 12 14 16 18 20 22 24
A
B
11
12
13 λ:348 nm5
7
11
12
135 λ:286 nm
6
Minutes0 2 4 6 8 10 12 14 16 18 20 22 24
59 104 8 λ:450 nm1311
31 2
12C
2 4 6 8 10 12 14 16 18 20 22 24Minutes
1 = Violaxanthin (5.5)2 = Antheraxanthin? (7.0)3 = Unknown (7.2)4 = Unknown (7.4)5 = Lutein (8.4)6 = Phytoene (12.6)7 = Phytofluene (13.5)8 = β-cryptoxanthin? (13.8)9 = Unknown (14.6)10 = 15-cis-β-carotene? (15.2)11 = 13-cis-β-carotene (15.7)12 = All-trans- β-carotene (17.8)13 = 9-cis-β-carotene (18.6)
GM3736-54
All-trans-beta carotenes= 29.47 ug/g DM
Phytoene = 13.69 ug/g DM
Phytofluene= 7.44 ug/g DM
Minutes0 2 4 6 8 10 12 14 16 18 20 22 24
Minutes0 2 4 6 8 10 12 14 16 18 20 22 24
Minutes0 2 4 6 8 10 12 14 16 18 20 22 24
A
11
12
135 λ:286 nm
6
B 1112
13λ:348 nm
5 7
59 104 8 λ:450 nm
1311
31 2
12C
2 4 6 8 10 12 14 16 18 20 22 24Minutes
1 = Violaxanthin (5.5)2 = Antheraxanthin? (7.0)3 = Unknown (7.2)4 = Unknown (7.4)5 = Lutein (8.4)6 = Phytoene (12.6)7 = Phytofluene (13.5)8 = β-cryptoxanthin? (13.8)9 = Unknown (14.6)10 = 15-cis-β-carotene? (15.2)11 = 13-cis-β-carotene (15.7)12 = All-trans- β-carotene (17.8)13 = 9-cis-β-carotene (18.6)
GM3739-13
All-trans-BC= 20.53 ug/g DM
Phytoene = 2.15 ug/g DM
Phytofluene= 1.39 ug/g DM
Missing values
Min Max Mean
Dry matter content (%) 36 9.8 52 34HCN Total(ppm) 2621 23.3 3927 792Total carotenoids (ug/g fresh weight) By spectrophotometer 24 0.24 25 10 By HPLC 271 0.11 26 10β-carotene (ug/g FW) 270 0.0 17 6.0Anteroxanthins (ug/g FW) 279 0.0 3.0 0.3Violaxanthins (ug/g FW) 707 0.0 1.6 0.3Luteins (ug/g FW) 277 0.0 3.9 0.4β-Criptoxantihns (ug/g FW) 854 0.0 1.1 0.115-cis-β carotene (ug/g FW) 705 0.0 1.5 0.113-cis-β carotene (ug/g FW) 277 0.0 3.4 0.99-cis- βcarotene (ug/g FW) 277 0.0 3.4 0.9Phytoen(ug/g FW) 986 0.0 18.6 3.6Phytofluen(ug/g FW) 1564 0.0 8.8 1.8Parameters from Minolta Chromameterl* 1985 53 104 73a* 1985 -3.8 52 24b* 1985 44 127 97
Wet chemistry descriptive statistics (2009-2012 data; N=3419)
Calibration curves (2009-2011)
Dry Matter
Total HCN
R2: 0.947SECV: 1.604R2 SECV: 0.937RPD: 4.0
R2: 0.812SECV: 309.0R2 SECV: 0.766RPD: 2.1
Total Carotenoids Colorimetry
Total Carotenoids HPLC
R2: 0.911SECV: 1.191R2 SECV: 0.906RPD: 3.3
R2: 0.897SECV: 1.500R2 SECV: 0.887RPD: 3.0
Beta Carotene HPLC
Provitamin A
R2: 0.928SECV: 0.837R2 SECV: 0.922RPD: 3.6
R2: 0.910SECV: 1.099R2 SECV: 0.901RPD: 3.2
Scatter plot of Dry Matter Content NIRS predicted values (from equations developed using 2009-2011 data) vs. laboratory values (from 2012 nursery)
Scatter plot of total carotenoids NIRS predicted values vs. laboratory values (HPLC and spectrophotometer).
Scatter plot of β-carotene NIRS predicted values (based on equations developed from 2009-2011 data) vs. laboratory values (from 2012 nursery)
Sampling and processing protocols
Analysis & pre-selection based on NIRS
Genetics of carotenoids
Genetic progress
Next steps: the pathway to impact
The Molecular Genetics Approach -- Requires:
• Understanding of the factors affecting high β-carotene accumulation.
• Understanding of the β-carotene biosynthetic pathway.
• A good segregating mapping population (F1 vs. Fn).
• Large number of molecular markers (e.g. SNPs)
• Good field design.
• A high-fidelity phenotyping system.
Carotene biosynthetic pathway
IPP
Geranylgeranyl diphosphate
Phytoene
Lycopene
-carotene(vitamin A precursor)
Phytoene synthase
Phytoene desaturase
Lycopene-beta-cyclase
ξ-carotene desaturase
isopentenyl diphosphate
Segregation for beta carotene and its building blocks in an F2 population
0.00
5.00
10.00
15.00
20.00
25.00
30.00
GM 3
732-
22GM
373
6-78
GM 3
736-
40GM
373
6-29
GM 3
736-
16GM
373
6-85
GM 3
736-
84GM
373
6-37
GM 3
732-
8GM
373
2-28
GM 3
736-
32GM
373
2-11
GM 3
736-
15GM
373
2-2
GM 3
732-
26GM
373
6-59
GM 3
736-
26GM
373
6-69
GM 3
732-
19GM
373
6-20
GM 3
736-
66GM
373
2-27
GM 3
732-
34GM
373
6-54
GM 3
736-
57GM
373
6-12
GM 3
732-
16GM
373
2-18
GM 3
736-
2GM
90
5-60
GM 3
736-
34GM
373
6-51
GM 3
732-
31GM
373
2-29
GM 3
732-
30GM
373
2-17
GM 3
736-
63GM
373
6-36
GM
905-
52GM
373
2-1
GM 3
736-
3GM
90
5-57
GM 3
736-
18GM
373
2-13
GM 3
732-
5GM
373
6-43
GM 3
736-
53GM
373
6-6
GM 3
732-
37GM
373
6-44
GM 3
736-
17GM
373
2-21
GM 3
736-
4GM
373
6-72
GM 3
732-
23GM
373
2-9
GM 3
736-
48GM
373
6-77
GM 3
736-
38GM
373
6-45
GM 3
736-
60GM
373
6-52
GM 3
732-
25GM
373
6-24
GM 3
736-
73GM
373
6-75
GM 3
732-
36GM
373
6-11
GM 3
736-
23GM
373
2-20
GM 3
732-
35GM
373
2-32
GM 3
736-
5GM
373
2-4
GM 3
736-
25GM
373
2-12
GM 3
732-
14GM
373
2-33
GM 3
736-
22GM
373
6-79
GM 3
736-
41GM
373
2-6
GM 3
732-
3GM
373
6-61
GM 3
736-
10GM
373
6-27
GM 3
736-
28GM
373
6-47
GM 3
736-
9GM
373
6-35
GM 3
736-
71GM
373
6-50
GM 3
736-
39GM
373
6-21
GM 3
732-
24GM
373
2-7
GM 3
736-
30GM
373
6-55
GM 3
736-
33GM
373
2-15
GM 3
736-
70GM
373
2-10
GM 3
736-
42GM
373
6-64
GM 3
736-
65GM
373
6-14
GM 3
736-
82GM
373
6-81
GM 3
736-
62GM
373
6-1
GM 3
736-
83GM
373
6-67
CaroTcol (μg/g) B.F. CaroTHPLC (μg/g) B.F. All trans BC (μg/g) B.F. 13-Cis-BC (μg/g) B.F. 9-Cis-BC (μg/g) B.F.
Antheraxanthin?? (μg/g) B.F. Lutein (μg/g) B.F. Phytoene (μg/g) B.F. Phytofluene (μg/g) B.F.
Highest β-carotene level was shown by genotype GM3732-22
GM
905-
52
GM
905-
57
GM
905-
60
Ƃ
Ƃƃ
ƃ
x GM3736
GM3732x
Carotenoid distribution in GM373X
0
5
10
15
20
25
30
35
40
45
GM
3732
-28
GM
3736
-78
GM
3736
-84
GM
3736
-29
GM
3732
-19
GM
3732
-22
GM
3736
-75
GM
3736
-40
GM
3736
-56
GM
3736
-26
GM
3736
-45
GM
3736
-37
GM
3736
-34
GM
3732
-02
GM
3732
-05
GM
3732
-34
GM
3736
-17
GM
3736
-16
GM
3732
-17
GM
905-
57G
M37
36-3
2G
M37
36-1
5G
M37
32-1
8G
M37
36-5
8G
M37
36-5
9G
M37
32-1
1G
M37
32-0
8G
M37
36-7
7G
M37
36-2
0G
M37
36-6
9G
M90
5-60
GM
3732
-29
GM
3732
-30
GM
3736
-66
GM
3736
-38
GM
3736
-36
GM
3732
-01
GM
3736
-76
GM
3732
-21
GM
3736
-51
GM
3736
-43
GM
3732
-16
GM
3736
-18
GM
3736
-85
GM
3736
-12
GM
3736
-44
GM
3732
-37
GM
3732
-13
GM
3736
-13
GM
3736
-02
GM
3736
-06
GM
3736
-48
GM
3736
-53
GM
3736
-54
GM
3736
-74
GM
3732
-23
GM
3732
-36
GM
3736
-72
GM
3732
-31
GM
3736
-57
GM
905-
52G
M37
36-5
2G
M37
36-0
3G
M37
36-0
8G
M37
32-2
5G
M37
36-1
9G
M37
36-1
1G
M37
32-2
7G
M37
36-2
3G
M37
36-8
0G
M37
32-1
2G
M37
32-3
5G
M37
36-0
5G
M37
36-7
9G
M37
32-1
4G
M37
32-0
4G
M37
36-6
3G
M37
32-2
0G
M37
32-3
2G
M37
32-0
9G
M37
36-2
4G
M37
36-2
5G
M37
36-4
1G
M37
32-3
3G
M37
36-7
3G
M37
32-0
3G
M37
36-1
0G
M37
32-0
6G
M37
36-2
2G
M37
36-6
1G
M37
36-3
5G
M37
36-4
7G
M37
36-2
1G
M37
36-3
0G
M37
36-2
7G
M37
36-7
0G
M37
32-0
7G
M37
36-3
9G
M37
32-1
5G
M37
36-4
9G
M37
36-8
1G
M37
32-1
0G
M37
36-0
9G
M37
36-3
3G
M37
36-5
0G
M37
32-2
4G
M37
36-2
8G
M37
36-7
1G
M37
36-6
4G
M37
36-1
4G
M37
36-5
5G
M37
36-8
2G
M37
36-4
2G
M37
36-4
6G
M37
36-6
2G
M37
36-6
7G
M37
36-0
1G
M37
36-8
3
PTFN 2012
PTH 2012
TCH 2012
Caro
teno
id G
aine
dCa
rote
noid
Pot
entia
l
IPP
Geranylgeranyl diphosphate
Phytoene
Lycopene
-carotene(vitamin A precursor)
Phytoene synthase
Phytoene desaturase
Lycopene-beta-cyclase
ξ-carotene desaturase
Potential of intermediate products that are being retained in the pathway (not converted to beta carotene)
Carotenoid distribution in GM373X
0
5
10
15
20
25
30
35
40
45
GM
3732
-28
GM
3736
-78
GM
3736
-84
GM
3736
-29
GM
3732
-19
GM
3732
-22
GM
3736
-75
GM
3736
-40
GM
3736
-56
GM
3736
-26
GM
3736
-45
GM
3736
-37
GM
3736
-34
GM
3732
-02
GM
3732
-05
GM
3732
-34
GM
3736
-17
GM
3736
-16
GM
3732
-17
GM
905-
57G
M37
36-3
2G
M37
36-1
5G
M37
32-1
8G
M37
36-5
8G
M37
36-5
9G
M37
32-1
1G
M37
32-0
8G
M37
36-7
7G
M37
36-2
0G
M37
36-6
9G
M90
5-60
GM
3732
-29
GM
3732
-30
GM
3736
-66
GM
3736
-38
GM
3736
-36
GM
3732
-01
GM
3736
-76
GM
3732
-21
GM
3736
-51
GM
3736
-43
GM
3732
-16
GM
3736
-18
GM
3736
-85
GM
3736
-12
GM
3736
-44
GM
3732
-37
GM
3732
-13
GM
3736
-13
GM
3736
-02
GM
3736
-06
GM
3736
-48
GM
3736
-53
GM
3736
-54
GM
3736
-74
GM
3732
-23
GM
3732
-36
GM
3736
-72
GM
3732
-31
GM
3736
-57
GM
905-
52G
M37
36-5
2G
M37
36-0
3G
M37
36-0
8G
M37
32-2
5G
M37
36-1
9G
M37
36-1
1G
M37
32-2
7G
M37
36-2
3G
M37
36-8
0G
M37
32-1
2G
M37
32-3
5G
M37
36-0
5G
M37
36-7
9G
M37
32-1
4G
M37
32-0
4G
M37
36-6
3G
M37
32-2
0G
M37
32-3
2G
M37
32-0
9G
M37
36-2
4G
M37
36-2
5G
M37
36-4
1G
M37
32-3
3G
M37
36-7
3G
M37
32-0
3G
M37
36-1
0G
M37
32-0
6G
M37
36-2
2G
M37
36-6
1G
M37
36-3
5G
M37
36-4
7G
M37
36-2
1G
M37
36-3
0G
M37
36-2
7G
M37
36-7
0G
M37
32-0
7G
M37
36-3
9G
M37
32-1
5G
M37
36-4
9G
M37
36-8
1G
M37
32-1
0G
M37
36-0
9G
M37
36-3
3G
M37
36-5
0G
M37
32-2
4G
M37
36-2
8G
M37
36-7
1G
M37
36-6
4G
M37
36-1
4G
M37
36-5
5G
M37
36-8
2G
M37
36-4
2G
M37
36-4
6G
M37
36-6
2G
M37
36-6
7G
M37
36-0
1G
M37
36-8
3
PTFN 2012
PTH 2012
TCH 2012
Caro
teno
id G
aine
dCa
rote
noid
Pot
entia
l
Potential contributions of carotenoids not being converted to pro-vitamin A (degraded)
Carotenoid distribution in GM373X
0
5
10
15
20
25
30
35
40
45
GM
3732
-28
GM
3736
-78
GM
3736
-84
GM
3736
-29
GM
3732
-19
GM
3732
-22
GM
3736
-75
GM
3736
-40
GM
3736
-56
GM
3736
-26
GM
3736
-45
GM
3736
-37
GM
3736
-34
GM
3732
-02
GM
3732
-05
GM
3732
-34
GM
3736
-17
GM
3736
-16
GM
3732
-17
GM
905-
57G
M37
36-3
2G
M37
36-1
5G
M37
32-1
8G
M37
36-5
8G
M37
36-5
9G
M37
32-1
1G
M37
32-0
8G
M37
36-7
7G
M37
36-2
0G
M37
36-6
9G
M90
5-60
GM
3732
-29
GM
3732
-30
GM
3736
-66
GM
3736
-38
GM
3736
-36
GM
3732
-01
GM
3736
-76
GM
3732
-21
GM
3736
-51
GM
3736
-43
GM
3732
-16
GM
3736
-18
GM
3736
-85
GM
3736
-12
GM
3736
-44
GM
3732
-37
GM
3732
-13
GM
3736
-13
GM
3736
-02
GM
3736
-06
GM
3736
-48
GM
3736
-53
GM
3736
-54
GM
3736
-74
GM
3732
-23
GM
3732
-36
GM
3736
-72
GM
3732
-31
GM
3736
-57
GM
905-
52G
M37
36-5
2G
M37
36-0
3G
M37
36-0
8G
M37
32-2
5G
M37
36-1
9G
M37
36-1
1G
M37
32-2
7G
M37
36-2
3G
M37
36-8
0G
M37
32-1
2G
M37
32-3
5G
M37
36-0
5G
M37
36-7
9G
M37
32-1
4G
M37
32-0
4G
M37
36-6
3G
M37
32-2
0G
M37
32-3
2G
M37
32-0
9G
M37
36-2
4G
M37
36-2
5G
M37
36-4
1G
M37
32-3
3G
M37
36-7
3G
M37
32-0
3G
M37
36-1
0G
M37
32-0
6G
M37
36-2
2G
M37
36-6
1G
M37
36-3
5G
M37
36-4
7G
M37
36-2
1G
M37
36-3
0G
M37
36-2
7G
M37
36-7
0G
M37
32-0
7G
M37
36-3
9G
M37
32-1
5G
M37
36-4
9G
M37
36-8
1G
M37
32-1
0G
M37
36-0
9G
M37
36-3
3G
M37
36-5
0G
M37
32-2
4G
M37
36-2
8G
M37
36-7
1G
M37
36-6
4G
M37
36-1
4G
M37
36-5
5G
M37
36-8
2G
M37
36-4
2G
M37
36-4
6G
M37
36-6
2G
M37
36-6
7G
M37
36-0
1G
M37
36-8
3
PTFN 2012
PTH 2012
TCH 2012
Caro
teno
id G
aine
dCa
rote
noid
Pot
entia
l
Unknown Carotenoids
Identification of unknown carotenoids
Figure 5: Cassava carotenoids profile at 286, 348 and 450 nm of wavelength
1 = Violaxanthin (5.5)
2 = Antheraxanthin? (7.0)
3 = Unknown (7.2)
4 = Unknown (7.4)
5 = Lutein (8.4)
6 = Phytoene (12.6)
7 = Phytofluene (13.5)
8 = β-cryptoxanthin? (13.8)
9 = Unknown (14.6)
10 = 15-cis-β-carotene? (15.2)
11 = 13-cis-β-carotene (15.7)
12 = All-trans- β-carotene (17.8)
13 = 9-cis-β-carotene (18.6)
11
11
12
12
13
135
59 104 8
λ:286 nm
λ:348 nm
λ:450 nm
A
B
C12
13113
2 4
12
5
7
6
6 8 10 12 14 16 18 20 22 24Minutes
9
10
Molecular Genetics
• Generate high density markers (SSRs and SNPs)
• Build a consensus genetic map.
• Conduct statistical association between trait values and the genotypes of marker loci
• Evaluate changes at the DNA sequence level on genes involved in the carotenoid that may explain high β-carotene varietal improvement (MePSY2 SNP-AC)1.
SSRY171b0.0
CDM-24841644.2
CDM-24748460.2CDM-24878560.9CDM-24721561.7CDM-8131268.0CDM-24941068.1CDM-8191971.4SSRY79c80.1
CK65126789.4
CDM-250088120.3SSRY32123.5
1
CK643307b0.0
SSRY177c12.3
CDM-8165624.7
CDM-24802451.3CDM-25513051.4
CDM-25572779.0CDM-24923079.2SSRY10590.3
CDM-82740141.2CDM-81911148.6
NS40a188.1
CK643307a204.1
2
1 Welsch, R. et al. Provitamin A Accumulation in Cassava (Manihot esculenta) Roots Driven by a Single Nucleotide Polymorphism in a Phytoene Synthase Gene. The Plant Cell Online 22, 3348-3356, doi:10.1105/tpc.110.077560 (2010).
Conclusions from genetics studies
• Potential both to promote synthesis of beta carotene and stop the degradation
• Fully characterizing beta carotene biosynthesis pathway to maximize genetic gains
• Explored one mutation associated with the color trait. Yellow color determined by more than one gene.
Sampling and processing protocols
Analysis & pre-selection based on NIRS
Genetics of carotenoids
Genetic progress
Next steps: the pathway to impact
high-carotenoids progenitors crossed
Seed germinated, F1 plants evaluated at 11 MAP
Visual selection in the field. Pre-selection by NIRS. Selection based on total carot. content and total beta carotene
Planting of a new crossing nursery
RAPID CYCLING RECURRENT SELECTION
(3-year cycle)
Clonal evaluation trial
Preliminary yield trial
Advanced yield trial
Regional trial
IN PALMIRATO ACID SOILSAVANNAS FORSED AND CBB
Dry Matter %
Total carot. (spectroph.)
Total carot. (HPLC)
Total β-carotene
Total carot. (DW basis)
YEAR OF ORIGINAL NURSERY2004 35 7.8 8.2 5.3 252005 38 9.2 9.6 5.5 262006 36 7.5 7.3 4.7 212007 37 10.3 10.9 7.2 302008 37 10.4 10.9 6.2 302009A 38 11.8 12.4 7.5 322009B 39 13.0 13.8 8.6 36AGE OF PLANTS SAMPLED (MAP)8 38 9.5 10.0 6.5 269 38 10.4 11.1 7.1 2910 38 10.6 10.7 6.7 2811 35 10.1 10.5 5.8 30
Nutritional traits across years and plant ages
Human consumption: Results of evaluation nurseries for high-carotenoids roots
2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 20130
5
10
15
20
25
30
35
40
45
f(x) = 2.06 x − 4118.48R² = 0.877804592153342
f(x) = − 0.233333333333333 x + 502.955555555555R² = 0.0470867100163315
45
40
35
30
Evolution of dry matter content
Evolution of total carotenoids content
Tota
l car
oten
oids
con
tent
(μg/
g FW
)
Dry
matt
er c
onte
nt (%
)
Year
DM Content Total carot.
(spectro.)
Total carot.
(HPLC)
Total
β-carotene
Total carot.
(DW basis)
Across Locs 0.49 0.82 0.90 0.54 2.03
Uni. Nac. 0.13 0.72 0.94 0.64 2.47
CIAT 0.66 0.84 0.86 0.48 1.76
Regression for carotenes and carotenoids on year of selection
(Independent variable is year of original nursery)
Results indicate that an indirect effect of selection for high-carotenoids content was an increase in DMC !!!
Fresh root yield
Harvest Index
Dry matter content
Dry matter yield
Plant type score
(t/ha) (0-1) (%) (t/ha) (1-5)
Data from 46 selected genotypes
Max 64 0.74 42 24 4.0
Min 23 0.37 32 9 1.0
Mean 40 0.51 36 14 2.8
Data from 170 genotypes evaluated
Max 64 0.74 42 24 5.0
Min 2.2 0.12 21 1 1.0
Mean 26 0.43 35 9 3.3
Clonal Evaluation Trial Results, 2011/12(First step in the selection for agronomic performance; based
on single row plots with 6-8 plants, no replications)
Evaluation Trials, Palmira, 2012
Clonal Evaluation TrialsPlanted May 2012 426 entriesPlanted August 2012 452 entries
Preliminary Yield TrialsPlanted August 2012 60 entries
Advanced Yield TrialsPlanted August 2012 30 entries
Results of evaluations for disease resistance in the acid soil savannas(Materials in preliminary and advanced trials, Palmira)
Disease score, 1= Excellent; 5= Very poor
Super Elongation Disease (SED) = 2.1 1.0 5.0
Cassava Bacterial Blight (CBB) = 1.0 1.0 3.0
Average Minimum Maximum
Sampling and processing protocols
Analysis & pre-selection based on NIRS
Genetics of carotenoids
Genetic progress
Next steps: the pathway to impact
Select high performance materials in multi-location yield trials• Tentative Partners: Corpoica (Colombia)
Prepare pathogen-free in-vitro materials for international shipment• CIAT GRU Plant Health Laboratory
Send selected clones to Haiti for recovery from in vitro culture and multiplication, and testing• Tentative partners: Catholic Relief Services
Processing trials and acceptability studies; studies on gender differentiation • Tentative partners: Catholic Relief Services; CRP 3.4 (Roots,
Tubers and Bananas)
Ortiz, D., T. Sánchez, N. Morante, H. Ceballos, H. Pachón, M.C. Duque, A.L. Chávez, and A.F. Escobar (2011). Sampling strategies for proper quantification of carotenoids content in cassava breeding. Journal of Plant Breeding and Crop Science 3(1):14-23.
Morillo-C., A. C., Y. Morillo-C., M. Fregene, H. Ramirez, A.L. Chávez, T. Sánchez, N. Morante and H. Ceballos-L. (2011). Diversidad genética y contenido de carotenos totales en accesiones del germoplasma de yuca (Manihot esculenta Crantz). Acta Agronómica 60(2): 97-107.
Ceballos, H., J. Luna, A.F. Escobar, J.C. Pérez, D. Ortiz, T. Sánchez, H. Pachón and D. Dufour (2012). Spatial distribution of dry matter in yellow fleshed cassava roots and its influence on carotenoids retention upon boiling. Food Research International (45:52-59).
Morillo-C., Y., T. Sánchez, N. Morante, A.L. Chávez, A.C. Morillo-C., A. Bolaños, and H. Ceballos (2012). Estudio preliminar de herencia del contenido de carotenoides en raíces de poblaciones segregantes de yuca (Manihot esculenta Crantz). Acta Agronómica 61(3):253-264.
Recent publications:
Contributors
• CIAT’s breeding team (Hernan Ceballos, Fernando Calle and Nelson Morante)
• CIAT’s starch quality lab (Dominique Dufour, Teresa Sanchez, Monica Pizarro)
• CIAT’s nutritional lab (Darwin Ortiz, Moralba Dominguez)
• CIAT’s cassava genetics lab (Luis Augusto Bececerra, Tatiana Ovalle, Adriana Alzate)
• CIARAD collaboration (Fabricio Davrieux )