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GENETIC ENHANCEMENT OF BETA-CAROTENE IN STORAGE ROOTS OF CASSAVA VARIETIES IN AFRICA
 

GENETIC ENHANCEMENT OF BETA-CAROTENE IN STORAGE ROOTS OF CASSAVA VARIETIES IN AFRICA

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Screening cassava germplasm for ß-carotene,Evaluation of ß-carotene-rich genotypes: agronomic ...

Screening cassava germplasm for ß-carotene,Evaluation of ß-carotene-rich genotypes: agronomic
characteristics,Introduction of germplasm from within and outside SSA,Gene introgression for the improvement of ß-carotene levels..

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    GENETIC ENHANCEMENT OF BETA-CAROTENE IN STORAGE ROOTS OF CASSAVA VARIETIES IN AFRICA GENETIC ENHANCEMENT OF BETA-CAROTENE IN STORAGE ROOTS OF CASSAVA VARIETIES IN AFRICA Presentation Transcript

    • GENETIC ENHANCEMENT OF BETA-CAROTENE INSTORAGE ROOTS OF CASSAVA VARIETIES IN AFRICA: WHERE DO WE STAND? A.G.O. Dixon, G.N. Ssemakula, B. Maziya-Dixon and J.M. Ngeve International Institute of Tropical Agriculture, PMB 5320 Ibadan, Nigeria. International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
    • Outline Of Presentation Screening cassava germplasm for β-carotene Evaluation of β-carotene-rich genotypes: agronomic characteristics Introduction of germplasm from within and outside SSA Gene introgression for the improvement of β-carotene levels Deployment of β-carotene-rich germplasm to NARS in SSA Assessment of effect of processing on β-carotene retention in cassava foods and profiling of cassava carotenoids. Participatory on-farm trials and variety release Opportunities and challenges and the way Forward International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
    • The Cassava Germplasm Development- Africa Component of H+Initiated at IITA in 2003Global objective Develop cassava varieties with high ß-carotene, levels in the roots packaged in preferred agronomic backgrounds, and make these varieties available to farmers in SSA International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
    • Strategic objectives- Increase micro-nutrient (pVAC, Fe, Zn) content in cassava- Increase protein content in cassava- Reduce hydrocyanic acid content in cassava International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
    • Tactical objectives- Characterize cassava products for pVAC, Fe and Zn- Characterize cassava products for protein quality and quantity- Characterize cassava products for levels of HCN- Develop source populations for selection for these traits International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
    • Screening traits of interest in cassava germplasm Development of sampling method: which portion of the root? What maturity? Longitudinal, distal, central, and proximal portions of cassava roots Sampling at 6, 9, and 12 MAP Correlation between values from different portions International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
    • Mean micronutrient concentrations 6, 9, &12 MAP β-carotene (μg/g) Fresh root weight MAP 6 9 12 Mean 0.33 3.08 2.09 SE 0.25 0.88 0.65 β-carotene 6 & 9 MAP df =24 T value = -7.96 p <.0001 β-carotene 6 & 12 MAP df =24 T value = -7.34 p <.0001 β-carotene 9 & 12 MAP df =24 T value = 2.53 p = .0182 Sampling at 12 MAP adopted Visual rating for carotenoid concentration vs actual concentration International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
    • Carotenoids (fresh wt basis) from screening cassava in 4 yrs Year Total Total Screening method Deep Light Min Max No. No. yellow yellow TC TC families plants selected selected 2004/05 476 16,832 Color chart 24 379 - 10.1 μg/g † 2005/06 982* 19,644 Color chart, 895 1386 2.8 11.9 spectrophotometric μg/g μg/g 2006/07 490 8743 Color chart, 667 158 1.23 14.81 spectrophotometric μg/g μg/g 2007/08 638 28,865 Color chart, 1548 >500 1.56 13.27 spectrophotometric* Comprised of 133 families from CIAT, 59 from Brazil, and 790 local crosses from IITA Ibadan ;†Obtained from 2005 clonal evaluation; Screening done at different stages of the breeding prog. International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
    • Levels of pVAC in different stages of selection in 2009 Selection stage Range of pVAC in 2009/10 storage roots Clonal Evaluations 0.2 – 10.4 Advanced Yield Trials 4.7 – 11.1 Uniform Yield Trials (UYT) 0.58 – 9.5 International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
    • Levels of pVAC in genotypes advanced fromseedling nursery to clonal evaluation in 2009 International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
    • Levels of pVAC in genotypes selected andevaluated in advanced/UYT trials in 2009 International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
    • G x E: carotenoid concentration FW basis) AMMI:  High G –TC  G x E – highly sig for TC  Carotenoid concentration is a stable trait  Single location selection reliable International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
    • Agronomic superiority for acceptability Resistance to pests &  Seedling nursery diseases  Clonal Evaluation Stem yield & architecture  Preliminary Trial Root number & size/weight  Advanced Yield Trial Root quality  Uniform Yield Trials Stability - across locations  OFAR Trials International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
    • Agronomic characteristics and pest reactions of promising micronutrient-rich clonesClone CMD CGM Yield DM Carotene (t/ha) (%) (µg/g)05/1601 1.0 2.0 36.5 38.9 9.405/1600 3.2 2.5 34.5 29.0 6.505/1570 1.0 2.0 33.3 41.9 2.405/0327 1.0 4.5 28.4 37.8 6.205/1862 1.2 2.5 27.1 39.3 4.505/0311 1.0 2.5 25.7 40.9 5.505/0099 1.0 2.0 25.1 38.9 5.805/1654 1.0 3.0 23.0 34.9 6.905/0476 1.0 3.0 19.7 40.3 4.005/1652 1.0 2.5 19.5 31.3 8.3 International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
    • G x E : fresh root yield E effect highest for yield G x E*** for yield International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
    • G x E : DM content G effect highest for DM G x E*** for DM International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
    • Acquisition of β-carotene-rich and African adapted germplasmSource Form QuantityTanzania Landarace 18Malawi Landarace 14Zambia Landarace 11Latin America , Landarace , 44Thailand improved clonesCIAT Seed populations 207 families (4754 seeds)Brazil (thru CIAT) Seed populations 59 families (8074 seeds) International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
    • Introgression of genes to enhance carotene levels in IITA germplasmSeason Families Seeds2003/04 499 >160002004/05 790 19,6442005/06 490 14,0002006/07 859 33,5482007/08 725 54,2952008/09 166 9006Total 3529 146,493 International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
    • Deployment of germplasmCountry Seed families No. of seedsGuinea 71 >10,100Congo DR 30 >10,000Uganda 64 >10,100Kenya 23 >23,000Malawi 24 >24,000Angola 23 >23,000Mozambique 23 >23,000Sierra Leone 23 >46,000Ghana 17 >18,100 Virus-free certified tissue culture plantletsHS seed families International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
    • Polyploid breeding for enhanced carotene content Colchicine induced polyploidy >20 YR Clones 4x versus 2x counterparts Effect of polyploidization on carotene content (carotene 4x>carotene2x) Tetraploid x diploid crosses for more productive triploids International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
    • Comparative analysis for total carotene and dry matter content of 20 artificially induced Tetraploids (4x) vs their diploid counterparts (2x) TC DM % Parameter 2X 4XMean Mean 2X 4X Mean 4.7 5.45.03 35.5 36.78 33 SE 0.6 0.70.59 0.75 0.9 0.7 Min 0.4 0.70.57 29.67 27.19 28 Max 8.4 10 9.18 42.44 42.49 38 Pr>F (Ploidy level) *** *** Pr>F (Clone) *** *** Pr>F (Clone*Ploidy level) *** ***• Tetraploids had significantly higher concentrations of total carotene than diploids• Mean dry matter content of tetraploids was significantly lower than of diploids• Clone X ploidy level interaction was significant• Some tetraploid clones had higher dry matter content over the mean International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
    • Mutation breeding – (with IAEA)Worth of mutation breeding in enhancing nutrient concentrationEffect of irradiation with gamma rays/fast neutron on β-caroteneconcentration  TMS lines 01/1371, 98/0002 irradiated with gamma rays Mutants cloned and total carotene (TC) determined Parameter TC Mean 6.09 SE 0.12 Min 3.55 Max 9.74 N 112  30, 600 seeds irradiated (100 families), nursery ~ 2, 797 seedlings harvested, cloned and selfed International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
    • Nutrient loss during processing: an inevitable and unfortunate realityCrop Pot Plate Mouth Intestine International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
    • 100 90 Total carotene 80 β-carotene % nutrient retention 70 Iron 60 Zinc 50 Highest nutrient retention in boiled roots 40 30 20 10 0 Boil Raw fufu Cooked fufu Gari chips Processed productTrue micronutrient retention (%) of cassava products prepared fromfresh storage roots of three elite yellow-fleshed cassava clones International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
    • True micronutrient retention (%) of gari prepared from 24 elite yellow-fleshed cassava clones 50 45 Total carotenoids in fresh roots (µg/g) 40 Total carotenoids in Gari (µg/g) 35 % True total carotenoids retention* 30 25 20 15 10 5 0 01 5 01 4 01 5 73 01 7 01 1 01 5 01 8 01 1 01 2 13 01 2 01 0 01 6 01 9 01 2 90 63 94 6 95 0 98 9 32 4 55 1 2 3 7 3 3 6 7 1 4 1 4 4 6 0 3 7 /1 1 /1 2 /1 2 /1 2 /1 2 /1 3 /1 3 /1 3 /1 3 /1 4 /1 4 /1 4 /1 6 /1 6 /1 6 /1 6 /1 6 /0 0 /0 3 /0 3 /2 1 /0 1 01 01 01 94Micronutrient retention is genotype dependentGenetic variation for micronutrient retention can be exploited via breeding International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
    • 90% of carotenoids in cassava is β-carotene > 50% of carotenoids in cassava is Trans- β- caroteneCarotenoids profile of 22 yellow-fleshed cassava genotypes International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
    • Carotenoids species in yellow-fleshed cassavaclones evaluated at 5 locations in Nigeria, 2005/06 International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
    • Shift in nutrient levels with conventional breeding and selection for nutritional qualityMicro-nutrient Baseline 2003/2004 2004/2005 2005/2006 2006/2007 2007/2008 2008/2009Total carotene 0.4 μg/g 4.8 μg/g 10.1μg/g 11.9 μg/g 14.8μg/g 13.3 μg/g 10.4 μg/g International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
    • Participatory on-farm evaluation and release of yellow-fleshed cassavaPreferences Objectives 96/1089A, 01/1115, 01/1371, 01/1412,  Assess performance of yellow-fleshed clones under 01/1368, 98/2132, 30572, 01/1663, farmer managed conditions 01/1610, 01/1235, 01/1404  pluses (+)Selection criteria and minuses (-) of the clones – farmers’ perspective Yield, processed product yield and  Farmer size, no need to fortify quality, tuber exposure to yellow genotypes gari with palm oil, color, recognition Skeptical farmers- yellow cassava a Enugu, Ebonyi, tuber of 01/1404; itSE states: Abia, Imo, Anambra, Farmer carries a Akwa GMO?! Ibom,& Cross River weighed more than 6 kgSW states: Lagos, Ogun, Ondo, Ekiti, Oshun, & Oyo International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
    • Levels of acceptability of food from yellow root cassava: GariClone Color Texture Mealiness Starchiness Overall acceptability98/2132 5.9 5.3 5.1 4.7 5.901/1368 5.4 5.2 5.0 4.8 5.7 Scored on a94/0006 4.2 4.4 4.0 3.8 5.1 1-6 scale95/0379 4.7 4.6 4.0 4.6 5.0 where:96/1089A 4.3 4.8 4.3 4.7 4.9 1=poor01/1380 4.9 4.8 4.6 4.3 4.8 6= very90/01554 4.5 4.4 4.1 4.3 4.8 good01/1277 4.9 4.1 3.9 3.0 4.401/1649 4.7 3.9 3.9 3.7 4.401/1663 4.1 3.8 3.9 4.0 4.4TME 1 1.3 2.1 2.6 2.0 1.630572 4.2 4.1 3.6 3.8 4.691/02324 5.3 5.2 4.7 4.7 5.7 International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
    • Trait Association1. Correlation of Total Carotene (TC) to Fresh root Yield (FYLD) and dry mater content (DM) was negative and significant for some trials.2. Across all yellow root trials , the correlation remained negative but was not significant International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
    • Status of germplasm introduced to target NARS (Nigeria and DR Congo)Nigeria• Improved seed populations have been planted in seedling nurseries• Improved genotypes with high pVAC are in various selection trials• Three high pVAC genotypes are in pre-release trialsDR Congo• Improved seed populations have been planted in seedling nurseries• Improved genotypes with high pVAC are in various selection trials• Germplasm collection of high pVAC genotypes is maintained at Mvuazi• Hybridization of high pVAC parents is ongoing• Product and market development and sensitization key to release of new pVAC varieties before 2012. International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
    • Official Releases in AfricaNigeria: TMS 96/1089A - First ever Official release ofyellow-flesh cassava varietyDR Congo: TMS 94/0330 and TMS 01/1661 Yellow Gari White GariYellow cassava in Nigeria (Gari) and DR Congo (fufu, chikwangue,fresh roots) have higher price premium than white or cream ones International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
    • Characteristics of YR varieties released in DR Congo by INERA in June 2008. Total Fresh Dry Starch caroteneVariety Yield matter content CMD CBSD Color content (t/ha) (%) (%) (μg/g) FW94/0330 27.8 40.5 21.5 1.3 1.0 Yellow 5.2301/1661 39.6 28.8 14.0 1.0 1.0 Yellow 7.29TME - 45.6 39.3 28.9 1.0 1.0 White419RAV - 14.0 31.3 20.3 3.0 1.0 White(check) International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
    • Opportunities and challengesOpportunities High prospects of hitting the target level (15 μg/g) for β-carotene Some countries (Nigeria, DR Congo and Ghana) are already exposed to and/or using yellow root cassava - attitude may not be a major issue International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
    • Opportunities and challenges; lessons learntChallenges Some of the high carotenoid clones are weak, probably because they resulted from selfing Often high carotenoid clones have low DM and low yield Plateauing of Total Carotene Will have to develop early bulking varieties since carotene is lost with age in the ground, ie > 9 months International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
    • Way forward• Introduce diverse genotypes with higher levels of beta carotene (esp. mealy deep yellow/orange parents)• Identify parents with high breeding values for deep yellow- fleshed roots, mealiness, high dry matter content, low CnP and resistance to CMD and CBSD for use in crossing blocks• Develop source population for yellow-fleshed roots by crossing selected genotypes to locally adapted lines• Multiply and distribute available beta-carotene and agronomically superior genotypes for selection under local environmental conditions• Sensitize the population on the importance of consuming beta-carotene rich cassava varieties International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
    • • Investigating the underlying environmental and agronomic factors on pVAC trait expression• Use of index selection for overcoming the negative association between pVAC and yield/DM International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
    • Acknowledgements:HarvestPlus and IITA, NRCRI and INERA Thank You! International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org