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Cassava at CIAT. Annual Program Review 2011 Nairobi, Kenya 10 May 2011. Clair Hershey. Starches. Waxy cassava starch granules (AM206-5). Hidrolisis. Small granule cassava starch (5 G160-13).
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Cassava at CIAT Annual Program Review 2011 Nairobi, Kenya10 May 2011 Clair Hershey
Waxy cassava starch granules (AM206-5) Hidrolisis Small granule cassava starch (5 G160-13)
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 Waxystarch (wxwxSGSG) Small Granule WxWxsgsg X F1 (WxwxSGsg) Self-pollinated or crossed Wx-- SG-- (Normal starch) wxwx SG-- (Waxy starch) Wx -- sgsg (Small granule) wxwxsgsg (Double mutant) 784 S1 and 188 “F2”, transplanted at the end of 2010, will be harvested and tested by the end of 2011
y = 2.346x + 8.6995 R2 = 0.7763 Progress in total carotenoids content in cassava roots during the last six years of breeding 30 Maximum 25 20 TCC (µg/ g) 15 Average 10 5 Minimum 0 2005 2006 2007 2008 2009 2010 Year
Relevant results from the evaluations made in 2010 Nutritional goal of 15 ug established in 2005 achieved through a rapid cycling scheme
The use of colorimeter (based on 478 observations) for quantifying β-carotene: combining the two relevant parameters in a selection index: (a – (h2*10) 50 y = 2.4242x - 1.7686 2 R = 0.6247 40 30 20 Selection index 10 0 2 6 10 14 18 -10 -20 All trans β-carotene
First evaluation of post-harvest physiological deterioration in Thailand (Huey Bong) 1. Training on the procedure 2. Introduction of potential sources of tolerance
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 peelingcassava 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 (ManihotesculentaCrantz) roots” to be published in Plant Breeding adress this issue
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 weeksafter 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 preparations made to understand the development of the embryo sac in cassava
Training Lisette Natalia Ramos(Ph.D. student, wide crosses)
Plant Resources Colored root segregation pattern in an advance breeding family 17 μg 0 μg
Plant Resources Advance breeding family CM8996for WFR MEcu72 MCol2246 MCol2246 Susceptible MEcu 72 Resistant
Genetic and Genomics - MAS -Carotene Pathway in Plants IPP Geranylgeranyl diphosphate Phytoene synthase Phytoene Phytoene desaturase ξ-carotene desaturase Lycopene Lycopene-beta-cyclase -carotene (vitamin A precursor)
Genetic and Genomics - MAS • Cassava SSRs were Silver stained • TheseSSRsareexpensive & time consuming to perform
Genetic and Genomics - MAS • Electronic data capturing and analysis A B B 96 or 384 well-plates A B B A A B Previously developed genetic maps
Processes and time-frame for developing breeder ready tools N N • SNPdiscoveryby genome RESCANing N N N N N N N N N N RRG Barcode Non-Illumina Adapter BREAD: Extending Unisexuality and Heterosisto Cosexual Cereal Crops Illumina Adapter Barcode Combine at least 48 genotypes per sequencing lane ~2-3X coverage