Abstract Farmers who produce sweetpotato in Ethiopia save planting material on farm during the long dry months. Water stress and virus and weevil pressure during this period are the main causes of both the loss of farm-saved sweetpotato planting material and the country’s shortage of planting material. In other African countries, “Triple S” is a newly emerging root-based sweetpotato planting material conservation technique that has enabled small-scale farmers to conserve planting material for up to 3 months in dry periods. The dry months in Ethiopia last 3–5 months in the Southern Nations, Nationalities, and Peoples' Region (SNNPR) and 7–9 months in Tigray region, where direct adoption of the original Triple S technique is not feasible. Therefore, the aim of this study is to modify and test root-based sweetpotato planting material conservation methods appropriate for Ethiopia. In SNNPR, 12 farmer research groups compared Triple S techniques with shade conservation and conventional methods. In Tigray, an on-station trial was conducted to test the sprouting potential of different sizes (small, medium, and large) of roots stored in sand-filled containers after different storage periods. Results show that roots stored in sand-filled containers start sprouting 4–6 weeks after first being stored. On average, 82% of roots stored could sprout after 3, 4, and 5 months and be transplanted for vine multiplication. Forty-five days after transplanting, each root gave above-ground fresh vine yields of 883 g, 656 g, 680 g, and 615 g in Dorebafana, Kedidagamela, Humbo, and Mirab-Abaya woredas, respectively. Storing only 40 roots using Triple S can produce enough planting material to plant 400 m2 of land. In addition, the quality of vine produced through Triple S is better than that from farm-saved planting material in terms of being free of viruses and weevil. In our separate experiments to adapt Triple S for 8–9 months during the dry period in Tigray, 61%, 62%, and 52% of roots sprouted after 6 months of storage. The present study confirmed the potential of Triple S to increase the security of sweetpotato planting material in drought-prone areas in Ethiopia. Additional studies are being conducted to refine factors such as age and size of roots and storage and transplanting time. Mihiretu Cherinet

1. TESTING “TRIPLE S” IN A NEW CONTEXT: SWEET POTATO
PLANTING MATERIAL CONSERVATION OVER THE LONG DRY
PERIOD OF ETHIOPIA
October, 2016
African potato association
AddisAbeba
Ethiopia
Presented by: Mihiretu Cherinet
Mihiretu Cherinet, Gebrehiwot Hailemariam, Margaret McEwan and Beyene Dimstu
Coauthors:-

2. Introduction
• Chronic shortage of quality planting material is major constraints to
sweetpotato production in all parts of Ethiopia
• Farmers conventionally conserve planting material in the form of field growing
foliage as a source of vine cuttings
• However, all sweetpotato growing areas have none rainy dry months which
ranges from 3 to 9 months each year.
• Due to this farm saved planting material will ultimately dry out, causing
shortage in the planting season
• Shortage of PM results in delayed planting
• Early planting ensures early harvesting bridging the gap between first harvest
of grain crops

3. Effect of dry season on sweetpotato vine conservation

4. Root based planting material conservation
• Some farmers rely on volunteer sprouts from sprouted roots which is
• Accidental and may not give enough planting material
• Weevils, the main pest of the crop, often infest the cuttings (Smit and
Van Huis 1999) after surviving the dry season on the parent root.
• After harvest, fields in many areas are traditionally grazed by domestic
animals belonging to villagers, damaging the vines of volunteer sweet
potato plants (Namanda et al. 2011).
• Inovative approches were applied to minimize the above mentioned root
based PM conservation by Namanda et al, 2013.
• The structured new aproach was then named as triple S.

5. Triple S: a new approach of PM conservation in SSA
• What is triple S
• Storage in Sand and Sprouting
• First tested in Uganda and validated in Tanzania (Namanda et al.2012)
• Triple S`s has many advantages
• Conservation of clean PM in areas with prolonged dry season
• Protection from animal damage
• Protection from weevil damage
• Protection from infection against important diseases especially from virus disease

6. Objective of the study
Examine the extent of planting material shortage in different SP
producing areas of Ethiopia
Validate the importance of Triple S over conventional planting
material conservation in SNNPR where 3-5 months of dry season
Study the potential triple to fit 7-9 months of dry season in Tigray
Ethiopia

7. Experiment 1. Participatory validation of triple S in the
selected areas
• Started in 2014/2015 and 2015/2016 dry season
• Conducted in four woreda: Hawassa Zuria, KedidaGamela, Humbo
and Mirab Abaya woredas
• Three Farmers research group (FRGs)
• Ten farmers in each FRG, one farmer will be a host of the triple S
validation trial
• Total of 12 validation trials were set up in four different districts each
hosting three validation trials

8. Methodologies used for participatory
validation of triple S in areas with 3-5 months

9. SWEETPOTATO ACTION FOR SECURITY AND HEALTH IN AFRICA
Step 1: Formation of farmers research group in the
selected areas
During FRG formation
1. Farmers discussed about PM shortage after long summer
2. Trained about Triple S
3. Three treatments were selected for comparison

10. List of participating farmers
Location # of participant # of Female Male # of FRGS
Hawassa 30 20 10 3
M/Abaya 30 10 20 3
Humbo 19 5 14 3
K/gamela 29 12 17 3
The four locations are served as an experimental block and the three
FRGs in each locations are considered as replication
= 12 experimental
units

11. SWEETPOTATO ACTION FOR SECURITY AND HEALTH IN AFRICA
1. Roots planted in wet soil around backyard
2. Shade planting and Mulching
Location Local way of planting material
conservation
Major problem of
PM conservation
Hawassa zuria Volunteer , Shade Enset Drought, weevil
Mirab Abaya Mulching(grass & cow dung), root
planting in wet areas
Drought, weevil,
animal
Humbo Shade, Mulching and volunteer Drought, virus,
weevil
Kedida Gamela Shade, Mulching and volunteer Drought, Virus,
Weevil
Selected type of conservation to be compared with Triple S
Step 2: Participatory selection of local conservation
techniques to compare with Triple s techniques

12. Treatments and experimental design
• Treatment 1: Triple S
• Treatment 2: Volunteer
• Treatment 3: Shade and Mulch
40 roots are stored as triple S
20 roots are planted as volunteer
20 vine cuttings are planted in a shade

13. Description of selected techniques
Treatment One: Triple S techniques

14. SWEETPOTATO ACTION FOR SECURITY AND HEALTH IN AFRICA
1. Healthy root selection and cleaning
• Freedom from weevil and wound
• Clean dusts and wet soils
• Select medium sized roots

15. SWEETPOTATO ACTION FOR SECURITY AND HEALTH IN AFRICA
2. Sand preparation
Sun drying of collected moist sand collected from local areas

16. 3. Placing roots in plastic container
Forty roots were buried in each plastic container
SWEETPOTATO ACTION FOR SECURITY AND HEALTH IN AFRICA

18. 4. De-sprouting: if the sprouts grow big before the arrival of rain
SWEETPOTATO ACTION FOR SECURITY AND HEALTH IN AFRICA
Sprouting Sprouted roots De-sprouting
Putting back in sand

19. Treatment Two: volunteer crop
• These treatment is based on farmers practices of harvesting vines from root
sprouts after the start of rain. The roots are left over of the last harvest
SWEETPOTATO ACTION FOR SECURITY AND HEALTH IN AFRICA
In the picture farmers are
planting roots in a 40 cm
depth soil
Farmers selected wet
areas in their yard
and buried 20 roots
in 40 cm depth by
using 50 cm x 50 cm
spacing

20. Treatment three: farmers based conservation practices
Mirababaya
SWEETPOTATO ACTION FOR SECURITY AND HEALTH IN AFRICA
Mulching cow dung and dry grass Shade planting
K/Gamela , Humbo & H/zuria
Shade planting
 20 plants are saved in the selected local conservation techniques same time
as the triple S formed

22. • 1. Survival rate over the long dry season
87.50%
35%
26%
0%
68%
40%
0.00%
10.00%
20.00%
30.00%
40.00%
50.00%
60.00%
70.00%
80.00%
90.00%
100.00%
Triple S Volunteer planting Local (shade + Mulch)
Survival of Triple S, Volunteer and Local
Survival% Weevil attack

24. Firstdate SeconddateThirddate Fourthdate
H-83 10-Dec-2014 23-Jan-15 28-Feb-2015 6-Apr-2015 8-May-2015 149.0
Kulfo 10-Dec-2014 23-Jan-15 28-Jan-2015 6-Apr-2015 8-May-2015 149.0
Humbo Kulfo 6-Feb-2015 17-Mar-15 26-Apr-15N/A 14-May-2015 97.0
Kulfo 28-Nov-2014 5-Jan-15 22-Feb-15 20-Mar-15 17-Apr-15 26-May-2015 179.0
H-83 28-Nov-2014 5-Jan-15 22-Feb-15 20-Mar-15 17-Apr-15 26-May-2015 179.0
Hawassa Kulfo 5-Mar-2015 17-Apr-15 12-May-15N/A 15-Jun-2015 102.0
Sprouting/Des-prouting
Totaldays
Kedida-Gamela
MirabAbaya
Location Varieties Startingdate
Dateof
transplant

25. • More than 60% of roots
buried in selected farm
yards could not pass
over the dry season
Weevil + Decay

26. 565
461
381 401
200
300
146
300
94
192
150 160
0
100
200
300
400
500
600
Dorebafana Humbo Mirab Abaya Kedida gamela
Vine length per root/plant 45 DAT (cm)
triple S shade volunteer
309
252
208 219
43
64
31
64
18 36 28 30
0
50
100
150
200
250
300
350
Dorebafana Humbo Mirab Abaya Kedida
gamela
Vine number after 45 DAT for 20
roots/cuttings
triple S shade volunteer
Triple S method of conservation could produce upto 600% cuttings than
Volunteer and shade planting

27. Treatments Weevil (%)Virus (scale) Vine vigor
Triple S 3 insignificant Very good
Volunteer 35 low short internode, tine
Shade planting 64 Very high short internode,
 Shade conserved PM showed higher rate of weevil and virus
symptom.
 Triple S method of PM conservation assured high quality vines in
terms of freedom from weevil, virus infection and vigor

29. Common planting material multiplication
field using sprouted roots which are
stored by “Triple S” techniques, in
Hawassa Zuria woreda (Kebele Jara
Dado). Variety Kulfo
Common planting material
multiplication field using sprouted roots
from “Triple S” techniques in Mirab
Abaya woreda. Variety; Hawassa-83

30.  Small (50-100 g), Medium (100-250 gm) and Large (250-500 gm) roots
were Stored using Triple S techniques to study the viability after 7-9 months
of storage
Desprouting: de-sprouting or cutting back the sprouts are done every time
when there is roots growing out
Placing back: every sprouting activity is followed by placing back of
desprouted roots back to the container
Roots were desprouted continuously for 8 months in 2016, and for 5 months
in 2015

31. De-sprouting of sprouted roots
• There were four de-sprouting during the storage time
1st = 47 Days After Storage
2nd = 82 DAS
3rd = 116 DAS
4th =147 DAS
5th =229 DAS

32. 67%
85%
62%
45%
58%
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
1 2 3 4 5
Large Medium Small
1= 47 Days After Storage
2= 82 DAS
3= 116 DAS
4=147 DAS
5=229 DAS
More than 58% of Medium seized roots could successfully stored for more than
7.5 months

33. 13
22
10
5
0
5
10
15
20
25
47 DAS 82 DAS 116DAS 147DAS
Sprout fresh weight (g)
Large Medium Small
As the storage length
increases, roots
produce few sprouts
Large roots start
sprouting earlier, but
delayed sprouting is
observed in the smaller
roots
Large roots start
sprouting earlier

34. Medium seized roots
showed lower percentage
of decaying as compared
to Large and Medium
sized roots
0
5
10
15
20
25
Large Medium Small

35. • Successful roots are now transplanted to evaluate vine productivity

36. Triple S is better than conventional planting material conservation for
farmers in Southern-Ethiopia regions where the dry none rainy period range
3-5months
Sweetpotato planting material conservation through triple S techniques
enables farmer to access weevil free, virus clean and higher quantity
planting material for southern Ethiopia region
Triple S ways of planting material conservation has high potential to areas
with 7-9 months of dry season like Tigray region of Ethiopia.
Medium seized roots are preferred for prolonged storage for planting
material conservation

37. Cont`d
It is necessary to generate science based evidences on sweetpotato
root physiology to standardize Triple S technology for different
context.
At this stage, triple S is proved to be a viable option for planting
material conservation in the context of Ethiopia