1. Triploidy: A tool to improve cassava as an efficient biofuel crop
Sheela,M.N.
Sreekumari,M.T.,Asha Devi,A.,
Ramanathan,S.,Abhilash,P.V. and Chakrabarti,S.K.
Central Tuber Crops Research Institute, Trivandrum, India
Presented at the Second Scientific meeting of the Global Cassava Partnership meeting held Kampala,Uganada,18-22,June2012

2. CASSAVA Born in Brazil, South America
Introduced to India during 17th century as a food security crop
Evolved as a profitable industrial crop
India’s productivity high : 32 t/ha
Area concentrated in southern peninsula
Used as secondary staple, cattle/poultry feed and
Industrial raw material
Raised in rain fed and irrigated production systems
Grown as mono crop, intercrop and mixed crop

3. CASSAVA MAP OF INDIA

4. BREEDING OBJECTIVES High yield
Good culinary qualities (taste, cooking time, mealiness etc)
High starch content :stability and quality
Low cyanogen content
Early maturity (5-6 months)
Resistance to pests and diseases especially
Cassava mosaic disease
Resistance to PPD
Drought tolerance
Other desirable agronomic attributes
(non-branching plant type, high harvest
index, nutrient efficiency fried chip making quality etc.).

5. CASSAVA STARCH Cheapest source: South east Asia and South Asia
40% higher than rice &25% more than maize
Value added products viz. starch, sago, flour, chips Textile industries
Pharmaceutical industries
Adhesives : Laundry, Fast food
Paper industry
Thippi used in poultry feed – mix.

6. Alcohol from cassava TRIPLOID CASSAVA
Starch Glucose Alcohol
Yield : L/ ton of fresh tubers
L/ ton of dry starch
To make cassava an efficient biofuel crop, drastic improvement in Yield, Starch & sugar content is needed
TRIPLOID CASSAVA

7. Production of high starch varieties Polyploidy breeding (Triploidy)
Cassava is an ideal crop for polyploidy breeding due to:
Low chromosome number (2n =36)
Cross pollination :amenability for hybridization and
Grown primarily for vegetative parts
Breeding objectives
Ideal plant type (erect non- branching / top branching)
Higher yield (> 35t/ ha)
Higher DM (> 45%) and extractable starch (>30%)
Resistance/ tolerance to CMD

8. Procedure: Production of Tripoids : Induction of tetraploids
Induction of tetraploidy by colchicine treatment (0.5% for 12 hr.)
Isolation of apparent tetraploids based on leaf size, shape and thickness
Confirmation of the ploidy status by cytological screening (2n=72)
Screening of 4x plants for flowering and pollen fertility
Isolation of fertile clones for use as male parents

9. Characteristics of tetraploids in Cassava for visual screening
Leaves: thicker, broader and coarser
Increase in length &girth of petioles
Leaf lobes : lower length/breadth index & higher leaf area index
Stomata: Increase in length, volume & aperture size; less no. per unit area
Increase in length of palisade cells

10. Characteristics of tetraploids in Cassava for visual screening
Increase in flower size & length of pedicels
Delayed flowering
Reduction in pollen fertility & seed setting

11. Production of triploids
Procedure:
Raising a pollination block
Crossing elite diploids with induced tetraploids (2x X 4x)
Seedling progeny
Isolating apparent 3x seedlings based on leaf characters
Cytological confirmation of the apparent triploids (2n= 3x= 54)

12. Majority of the triploids possess
Compact plant type, stout, tall and vigorous stem
Late branching due to sparse flowering nature
Broad, dark green leaves with acuminate leaf tip
More chloroplasts in stomatal guard cells (14-17)
as against 9-13 in diploids
High leaf retention capacity
High harvest index
Higher yield (> 35.0 t/ ha)
High dry matter (45 – 50 %)
Higher extractable starch content ( >30%)

13. Comparison of diploids, triploids & tetraploids

14. Comparison of diploids, triploids & tetraploids

15. Comparison of diploids, triploids & tetraploids

16. Performance of the triploid cassava clones in Multilocation trial
Tuber Yield/plant
Extractable starch content

17. Triploids in pipeline: High starch clones:
Production of triploids
A remarkable achievement in cassava productivity & 5-6 % increase in extractable starch content
Net return – about Rs.21,000 as additional income /ha.
New triploid hybrids out yielded all the released varieties
Triploids in pipeline:
High starch clones:
Tr16-6, Tr30-1, Tr11-8, Tr47-1
Early bulking hybrids: Tr2-18, Tr3-4, Tr2-15, Tr7-5

18. High starch triploid hybrids
Sree Apoorva
Sree Athulya
4-2
1- 6
6- 6

19. BREEDING FOR CASSAVA MOSAIC DISEASE RESISTANCE
Developed large number of hybrids incorporating the three different sources of CMD resistance.
Lines received from CIAT with resistance from TME lines (CMD2 gene).
Sree Padmanabha (TMS30001) having resistance from tropical Manihot series (TMS) with CMD1 gene.
Resistance in interspecific hybrids developed at CTCRI
Promising hybrids are in prerelease stage

20. Virus load in cassava resistant and susceptible varieties
Resistant clones
Susceptible released varieties

21. Evaluation of CMD resistant clones
Sl.
No.
Clone
Yield
t ha -1
Starch% No
Yield t ha -1 1
CR54A3
39.34
33.3 8
CR9A125
51.81
32.6 2
CR43-11
57.73
32.3 9
I-14-S17
34.10
42.5 3
CR20A-2
53.45
32.1 10
799/10S1
33.21
33.7 4
CR21-10
43.58
31.6 11
S1284
56.95
32.4 5
7MNGA-1
35.41
27.4 12
S537-2
29.65
26.0 6
CR43-2
35.96
31.5 13
IPS2-1
32.83
30.3 7
IMS2-8
22.59
29.4 14
SREE REKHA
31.61
24.5
CD(.05)
12.21

22. Variation in root flesh colour among cassava inbreds
CASSAVA BREEDING PROGRAMME
Clones with good tuber shape and fried chip quality : CR 20-A2
Clones with high nutritional quality viz high carotene , higher protein
Tolerance to post harvest physiological deterioration
Variation in root flesh colour among cassava inbreds

23. Protein content
Tuber crude protein : 1.11%-7.18% on DWbasis.
Leaf protein : % (DW) and %(FW)
Interspecific backcross hybrids recorded significantly higher tuber protein than the intervarietal hybrids and released varieties
Traits
Crude protein % (DW)
Dry matter (%)
Crude protein % (FW)
Starch % (FW)
1.0000 **
0.7399**
0.1890* **
0.8611** NS

24. Protein, dry matter and starch content of promising cassava clones
Clone No
Protein (% on dry weight basis)
Dry matter
(%)
Starch
Crude protein
True protein
CPT 20
4.35
3.05
30.54
19.63
CPH23
4.08
2.78
36.80
22.20
CPS30
6.48
5.23
36.82
18.28
CPT32
6.80
6.10
24.88
15.47
CPT40
7.18
5.94
28.78
19.29
CPT103
5.72
4.51
28.86
20.21
Sree Jaya
2.10
1.45
25.88
21.77 M4
2.34
1.95
38.14
27.75
S.E
0.69
0.63
1.8
1.26

25. Earliness : Short duration clones of 5-6 months
Ensure tuber availability to industry
Suited to rice based cropping systems
Adaptable to climate change
Overcome CBSD
9S165
9S127
9S132
NUTRIENT EFFICIENCY :7IIIE3-5 (K efficient hybrid)
Varieties for product diversification : Fried chips

26. CASSAVA BREEDING 1960-1990 1990-2010 2010 onwards PRECISION BREEDING
EXPERIMENTAL BREEDING
METHODOLOGY STANDARDISATION
GERPLASM EVALUATION
CLONAL SELECTION
,HYBRID PRODUCTION
DIRECTED BREEDING
HYBRID PRODUCTION BASED ON GCA/SCA
TRIPLOID PRODUCTION
INTERSPECIFIC HYBRIDS
TRUE SEED CULTIVATION
2010 onwards
PRECISION BREEDING

27. FUTURE THRUSTS
Development of CMD resistant tetraploid clones of high combing ability: In vitro/In vivo
Triploid with high yield & starch for biofuel
Development of PPD tolerant clones & CMD resistant Short duration clones
Varieties with high nutritional quality
Varieties for specific end product development: Fried chips, french-fries etc.

28. THANKS FOR LISTENING