Tuesday theme 1 1205 1220 large briefing room gurmu

1. G x E interaction and stability of
sweetpotato clones for root dry matter, β-
carotene and fresh root yield in Ethiopia
Fekadu Gurmu
South Agricultural Research Institute
African Potato Association Conference
10-13 October 2016
UNECA, Addis Ababa, Ethiopia

2. Introduction
• Sweetpotato is among most important root
crops in Ethiopia
• It is the second in terms of area coverage
• Sweetpotato is cultivated in diverse agro-
ecologies and hence exposed to the effects of G
x E interaction

3. Introduction…
• G x E interaction is a differential response of
varieties when grown across target
environments
• Presence of G x E interaction implies the need
for systematic selection and ranking of
varieties across representative environments
• Selection for wider/specific adaptation

4. Introduction…
• In Ethiopia, there is limited information on G x
E interactions and the stability of sweetpotato
clones.
• Therefore, understanding the nature of G x E
interactions and quantifying its magnitude is
essential for breeding, cultivar release and to
identify the most discriminating and
representative test environments in Ethiopia.

5. Objectives
• to estimate the magnitude of G x E
interactions
• to select stable and high yielding candidate
sweetpotato clones for RDMC, β-carotene
content and fresh root yield, and
• to identify the most discriminating and
representative test environments in Ethiopia.

6. Materials and method
• The experiment was conducted at six environments
in the southern part of Ethiopia

7. Materials and methods…
• 24 F1 progenies selected from 21 families
(diallel cross) and one check variety were used
for the study
• Design: A 5 x 5 simple lattice

8. Materials and methods…
• G x E and stability analysis was conducted
using GGE Bi-plot.
• SAS 9.3 and GenStat 14th edition software
were used to analyse data

9. Materials and methods…
No Genotypes
Genotypes
ID
Predominant
flesh color
RDMC
Flowering
habit
Code Color
1 Ukrewe x Ejumula-10 G1 7 IO 31.8 None
2 Ukrewe x Ejumula-13 G2 7 IO 32.4 None
3 Ukrewe x PIPI-1 G3 2 CM 40.9 None
4 Ukrewe x Naspot-1 G4 2 CM 41.0 Moderate
5 Ukrewe x Ogansagan-5 G5 7 IO 32.2 None
6 Resisto x Ejumula-7 G6 7 IO 34.1 None
7 Resisto x PIPI-1 G7 7 IO 31.3 None
8 Resisto x PIPI-2 G8 8 DO 29.1 Profuse
9 Resisto x PIPI-4 G9 2 CM 38.4 Sparse
10 Resisto x PIPI-14 G10 2 CM 39.8 None
11 Resisto x Temesgen-10 G11 2 CM 40.2 Sparse
12 Resisto x Temesgen-12 G12 7 IO 31.4 None
13 Resisto x Temesgen-14 G13 7 IO 31.7 None
14 Resisto x Temesgen-17 G14 7 IO 36.0 None
15 Resisto x Temesgen-23 G15 8 DO 28.9 Moderate
16 Resisto x Ogansagen-5 G16 4 PY 36.8 Profuse
17 Resisto x Ogansagen-16 G17 8 DO 29.7 None
18 Resisto x Ogansagen-20 G18 2 CM 38.4 Moderate
19 Resisto x Ogansagen-23 G19 7 IO 30.5 Profuse
20 Ejumula x PIPI-10 G20 7 IO 31.3 Sparse
21 Ejumula x PIPI-18 G21 8 DO 26.2 Moderate
22 Ejumula x PIPI-19 G22 8 DO 28.2 Profuse
23 Ejumula x Temesgen-15 G23 2 CM 32.5 None
24 Ejumula x Ogansagen-17 G24 7 IO 30.2 None
25 Tula G25 6 PO 28.5 None

10. Results and discussion
• Environment, genotype and G x E interaction
variances were significant (p < 0.01) for RDMC, β-
carotene content, and fresh root yield
RDMC
• The highest mean RDMC of 40.19% was recorded for
G11, followed by G16, G3 and G18 with means of
38.23, 37.15 and 36.23%, respectively

11. Results & Disc…
G8
G10
G12
G2
G11G19
G6
G18
G4
G17
G25 G16
G23
G15
G21
G14
G7
G9
G22 G20
G5
G24
G1
G13
G3
KOK
AM
ARE
DIL
HAL
HAW
4.00-2.00
-3.00
0.00
-2.00
2.00
-1.00
0.00
-1.00 3.00
3.00
1.00
1.00
2.00
PC1 ( 61.63%)
PC2(13.99%) Stability of the clones for RDMC

12. Results & Disc…
β-carotene content
• Across the test environments,
G8, G15 and G19 had the
highest β-carotene of
20.01, 16.59 and 16.30 mg 100 g-1, respectively.
• Eight genotypes, namely G3, G4, G9, G10,
G11, G16, G18 and G23, had no β-carotene
content across all the test environments

13. Results & Disc…
G8
G10
G12
G2
G11
G19
G6
G18G4
G17
G25
G16G23 G15
G21
G14
G7
G9
G22G20
G5
G24
G1
G13
G3
KOK
AM
ARE
DIL
HAL
HAW
4.00-2.00
-3.00
0.00
-2.00
2.00
-1.00
0.00
-1.00 3.00
3.00
1.00
1.00
2.00
PC1 ( 93.76%)
PC2(2.23%)
Stability of the clones for β-carotene

14. Results & Disc…
• Root yield
• G6 was the highest yielder across
environments with a mean of 26.92 t ha-1,
followed by G20 (25.46 t ha-1) and G1 (25.09 t
ha-1).

15. G16
G20
G14
G2 G8
G19
G6
G18
G4
G17G25
G1
G23
G10
G21
G11
G7
G12
G22
G9
G5
G24
G13
G3
G15
ARE
HAW
KOK
HAL
AM
DIL
6.00-2.00
-4.00
2.00
-2.00
0.00 4.00
4.00
0.00
2.00
PC1 (68.30%)
PC2(20.60%)
Results & Disc…
Stability of the clones for root yield

16. Results & Disc…
20
22
24
26
28
30
32
34
36
38
40
42
44
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
Rootdrymattercontent(%)
β-carotene content (mg 100 g-1)

17. Conclusion
 Three clones: Ukrewe x Ejumula-10 (G1), Resisto x
Ejumula-7 (G6) and Ejumula x PIPI-10 (G20) were
selected based on their performance and stability
 These clones had:
• RDMCs of 31.82, 32.60 and 30.06%
• High β-carotene contents of 12.48, 14.27 and
13.99 mg 100 g-1 and
• Stable and high fresh root yields of 25.09, 26.92
and 25.46 t ha-1

18. Conclusion…
• Stable genotypes with high RDMC but no β-
carotene such as G3 and G11 can be used as
breeding parents to improve the RDMC of
OFSP varieties.
• Similarly, stable genotypes with high β-
carotene content, but low RDMC, such as G8
can be considered as parent for breeding
aimed at enhancing the β-carotene content of
sweetpotato varieties.

19. Conclusion…
• Arbaminch was identified as the best
environment for sweetpotato screening in
southern Ethiopia followed by Halaba, Dilla
and Hawassa.
• The study demonstrated the possibility of
breeding sweetpotato varieties with a balance
of high RDMC, medium β-carotene content
and a high fresh root yield, with wide or
specific adaptation

20. Acknowledgements
• UKZN
• AGRA
• ACCI
• IFS
• SARI
• CIP-Uganda