ENHANCING FOOD SECURITY THROUGHIMPROVED SEED SYSTEMS OF APPROPRIATECASSAVA, RESILIENT TO CLIMATE CHANGE IN           EASTE...
Field screening of cassava for combined      tolerance to elevated atmospherictemperature and low soil moisture and farmer...
Understanding the basis of tolerance                • Leaf characteristics: Measurable/Observable                • Stem ch...
Objectives• Main Objectives To identify cassava varieties that are tolerant to moisture and heat stress  and understand m...
Materials and experimental Layout• 20 Cassava varieties selected from different parts  of country (Cassava selections for ...
Results• Phenotypic data (collected on a bimonthly  basis) and spectral data (daily for 2 weeks)  from trial• Correspondin...
Grouping of varieties• Depending on their phenotypic and physiological  reaction to stress, varieties were grouped into th...
Difference in cumulative leaf number observed for the twenty                           varieties 400 350 300 250 200 150 1...
Variations in leaf reflectance for                variety groupsVariety Groups   Intensity       09:00Hrs   12:00Hrs   15:...
One of the methods used in selection was leaf lobe retention!!!!                                                8MAP   6MA...
Differences in the rates of recovery observed
Results: Free Reducing Sugars (RS)     0.5    A                                                      0.9          B       ...
Changes in Cyanide Content                                                                                     1.2   B    ...
Total Pigments; Chla, Chlb, Cart                                                                               0.6        ...
Changes in carbohydrate Profiles 0.4               Total carbohydrate metabolite changes                         0.45     ...
Recovery after stress: Understanding                the mode ???The phenomena was observed in 266 BAM and 72-TME 14 earlie...
The selection criteria• A combination of phenotypic, physiological  , spectral and biochemical indicators have been  used•...
Some of the selected varieties at the end of peak                         stressStay green varieties                      ...
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Enhancing food security through improved seed systems of appropriate cassava, resilient to climate change in Eastern Africa

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Presented by Baguma Yona, Nuwamanya Ephraim, Magambo Stephen and Akoli Barbara at the First Bio-Innovate Regional Scientific Conference, Addis Ababa, Ethiopia, 25-27 February 2013

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Enhancing food security through improved seed systems of appropriate cassava, resilient to climate change in Eastern Africa

  1. 1. ENHANCING FOOD SECURITY THROUGHIMPROVED SEED SYSTEMS OF APPROPRIATECASSAVA, RESILIENT TO CLIMATE CHANGE IN EASTERN AFRICABaguma Yona, Nuwamanya Ephraim, Magambo Stephen and Akoli Barbara First Bio-Innovate Regional Scientific Conference United Nations Conference Centre (UNCC-ECA) Addis Ababa, Ethiopia, 25-27 February 2013
  2. 2. Field screening of cassava for combined tolerance to elevated atmospherictemperature and low soil moisture and farmer preferred attributes
  3. 3. Understanding the basis of tolerance • Leaf characteristics: Measurable/Observable • Stem characteristics: Measurable/ObservableMorphological • Root characteristics: Measurable/Observable • Others Graphical Analysis Results - 20081010 320 100 • Photosynthetic enzymes assay 900 Viscosity RVU 240 Speed RPM Temp C 80 • Anti oxidant enzymes assay 160 600 60 Biochemical • Carbohydrate and amino acid analysis 80 300 40 • Hormone and secondary metabolites 0 0 5 10 15 Time mins Newport S c i enti fi c P ty Ltd 20 25 • Photosynthetic capacity assessment • Nutrient allocation studies • Osmotic adjustment studiesPhysiological • Transpiration mechanisms • Water relations • Microarray analysis • Gene chip analysis • Quantitative reverse transcriptase PCR Genetic • Others3/4/2013 3
  4. 4. Objectives• Main Objectives To identify cassava varieties that are tolerant to moisture and heat stress and understand mechanisms behind observed tolerance and /or resistance.• Specific objectives 1. Screen Ugandan cassava germ-plasm for accessions with tolerance to low moisture stress 2. Screen Ugandan cassava germ-plasm for accessions with tolerance to elevated heat 3. Determine the effect of elevated heat, low moisture stress and their interaction on yield and yield components of cassava 4. Elucidate the genetic and biochemical basis of tolerance to heat and moisture stress in cassava
  5. 5. Materials and experimental Layout• 20 Cassava varieties selected from different parts of country (Cassava selections for drought tolerance study.doc)• Field experiment was set up in Kasese Western Uganda (Gmap Kasese)• Expt Design: RCBD with 4 replications, 2 stressed and 2 control (irrigated) (exptal layout)
  6. 6. Results• Phenotypic data (collected on a bimonthly basis) and spectral data (daily for 2 weeks) from trial• Corresponding biochemical and physiological data was taken on leaves• These datasets are being validated in second season trial
  7. 7. Grouping of varieties• Depending on their phenotypic and physiological reaction to stress, varieties were grouped into those that – Maintained a higher leaf area index (LAI) throughout stress as stay green varieties (SGV) – Regained at least half of total number of leaves immediately after stress or early recovering varieties (ERV) – Did not recover at all or took a long time to recover Susceptible varieties (SV)
  8. 8. Difference in cumulative leaf number observed for the twenty varieties 400 350 300 250 200 150 100 50 0 -50 -100 -150
  9. 9. Variations in leaf reflectance for variety groupsVariety Groups Intensity 09:00Hrs 12:00Hrs 15:00HrsStay green Red (%) 30.99 29.84 29.57 Green(%) 43.89 42.04 42.83 Blue(%) 25.31 28.12 27.59 Av. Intensity 0.523 0.538 0.537Early Recovery Red (%) 31.81 30.19 30.69 Green(%) 42.81 44.54 43.05 Blue(%) 25.36 25.27 26.26 Av. intensity 0.531 0.501 0.520Susceptible Red (%) 31.07 30.30 29.38 Green(%) 42.43 42.63 42.73 Blue(%) 26.51 27.08 27.89 Av. Intensity 0.548 0.495 0.559
  10. 10. One of the methods used in selection was leaf lobe retention!!!! 8MAP 6MAP 9MAPFrom 7-9 leaf lobes before the onset of stress to 5-4 leaflobes on mild stress, to 3-2-1 or sometimes deformed at maximum stress and to leafless stems in some varieties on some instances . This was followed by increase in sugarconcentration and secondary metabolites such as phenolics and tannins. Differences were 10MAPobserved in the different varieties for all these properties
  11. 11. Differences in the rates of recovery observed
  12. 12. Results: Free Reducing Sugars (RS) 0.5 A 0.9 B 0.8 0.4 0.7 y = 0.02x + 0.357 0.6 y = -0.0718x + 0.6025 0.3 R² = 0.477 0.5 R² = 0.1433 0.4 0.2 0.3 0.1 0.2 0.1 0 0 RS1(Wk1) RS2(WK3) RS3(WK5) RS4(WK7 RS1(Wk1) RS2(WK3) RS3(WK5) RS4(WK7 0.8 0.5 C y = 0.1104x + 0.2565 D y = -0.005x + 0.407 0.7 0.45 R² = 0.016 R² = 0.9271 0.4 0.6 0.35 0.5 0.3 0.4 0.25 0.3 0.2 0.15 0.2 0.1 0.1 0.05 0 0 RS1(Wk1) RS2(WK3) RS3(WK5) RS4(WK7 RS1(Wk1) RS2(WK3) RS3(WK5) RS4(WK7A=Changes in Reducing Sugars among stay green varieties B=Changes in Reducing Sugars for Early recovering varietiesC=Changes in Reducing Sugars for susceptible variety. D=Changes in reducing Sugars for all the varieties
  13. 13. Changes in Cyanide Content 1.2 B 1.4 A 1.2 1 y= 0.0713x + 0.3497 y = 0.025x + 0.633 R² = 0.1758 0.8 1 R² = 0.016 0.8 0.6 0.6 0.4 0.4 y = -0.003x + 0.399 0.2 R² = 0.002 y = -0.013x + 0.423 0.2 R² = 0.023 0 0 MC(WK1) MC(WK3) MC(WK5) MC(WK7) MC(WK9) MC(WK1) MC(WK3) MC(WK5) MC(WK7) MC(WK9) 1.6 C 1.8 D 1.4 1.6 1.2 1.4 y = -0.004x + 0.703 1 1.2 R² = 0.000 y=- 0.1034x + 0.9402 1 0.8 R² = 0.1097 CnP 0.8 Peel 0.6 0.6 y = -0.027x + 0.347 0.4 0.4 R² = 0.093 y = -0.042x + 0.432 R² = 0.108 0.2 0.2 0 0 MC(WK1) MC(WK3) MC(WK5) MC(WK7) MC(WK9) MC(WK1) MC(WK3) MC(WK5) MC(WK7) MC(WK9)A=Cyanide changes for all varieties throughout the stress period, B=Cyanide Change for stay green varieties, C= Cyanide change for early recoveringvarieties, D=Cyanide change for susceptible variety
  14. 14. Total Pigments; Chla, Chlb, Cart 0.6 Pigments for stay greens 0.5 Total pigment content0.45 0.5 y = -0.020x + 0.464 y = -0.040x + 0.514 0.4 R² = 0.324 R² = 0.680 0.40.35 0.3 y = 0.021x + 0.151 0.3 y = 0.013x + 0.1760.25 R² = 0.732 R² = 0.547 0.2 0.20.15 y = 0.004x + 0.080 y = 0.005x + 0.079 R² = 0.128 0.1 R² = 0.300 0.10.05 0 0 Harvest1 Harvest2 Harvest 3 Harvest 4 Harvest1 Harvest 2 Harvest 3 Harvest 4 0.45 Graph for early recovering genotypes 0.6 0.4 Pigments for susceptible y = 0.025x + 0.313 0.35 R² = 0.868 0.5 y = -0.014x + 0.446 R² = 0.045 0.3 0.4 y = 0.045x + 0.072 0.25 R² = 0.977 Chla 0.3 0.2 y = 0.007x + 0.169 Chlb R² = 0.029 cart 0.15 y = 0.015x + 0.042 0.2 R² = 0.961 y = 0.000x + 0.084 0.1 R² = 0.000 0.1 0.05 0 0 Harvest1 Harvest2 Harvest 3 Harvest 4 Harvest1 Harvest2 Harvest 3 Harvest 4
  15. 15. Changes in carbohydrate Profiles 0.4 Total carbohydrate metabolite changes 0.45 Carbohydrate profiles for Stay green0.35 0.4 y = 0.039x + 0.174 y = 0.009x + 0.251 R² = 0.432 0.35 0.3 R² = 0.0150.25 0.3 y = 0.012x + 0.156 R² = 0.308 0.25 0.2 0.2 y = 0.023x + 0.1380.15 y = -0.017x + 0.15 R² = 0.377 R² = 0.6 0.15 0.1 0.1 y = -0.023x + 0.1640.05 R² = 0.743 0.05 0 Harvest 1 Harvest 2 Harvest 3 Harvest 4 0 Harvest 1 Harvest 2 Harvest 3 Harvest 4 0.3 Carbohydrate profile for Early recovering 0.5 Carbohydrate profiles for susceptible varieties0.25 0.45 y = -0.006x + 0.216 R² = 0.067 0.4 0.2 y = -0.005x + 0.278 0.35 R² = 0.0020.15 0.3 Free RS y = -0.011x + 0.197 R² = 0.474 0.25 Bound RS 0.1 0.2 Starch y = -0.013x + 0.126 y = 0.015x + 0.162 Content R² = 0.634 R² = 0.291 0.150.05 0.1 y = -0.016x + 0.137 R² = 0.502 0 0.05 Harvest 1 Harvest 2 Harvest 3 Harvest 4 0 Harvest 1 Harvest 2 Harvest 3 Harvest 4
  16. 16. Recovery after stress: Understanding the mode ???The phenomena was observed in 266 BAM and 72-TME 14 earlier even before the rains set in.By the time of harvest (12MAP), plants had already achieved leaf numbers higher than earlier observed although massive remobilization of carbohydrates was observed in their roots. All varieties had a recovery mechanism. Difference was in the time of recovery after stress !!!
  17. 17. The selection criteria• A combination of phenotypic, physiological , spectral and biochemical indicators have been used• These include – Plant growth height and leaf/leaf lobe retention – Diurnal changes in pigment concentration (esp chla) – Relationships between absorbed spectra and pigment concentration (Diurnal changes in these) – Carbohydrate metabolism – Secondary metabolite changes
  18. 18. Some of the selected varieties at the end of peak stressStay green varieties NASE 2 MH97/0067 0686Early recovering varieties 266 BAM 72-TME 14 Typical susceptible variety NASE 1

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