2nd Year Progress Report
1st April 2008 – 31st March 2009
The research project aims to investigate and develop methods of improving
the management and utilisation of selected indigenous fruit trees of economic
value in Eastern Africa with the participation of local communities. The
selected tree species include: Balanites aegyptiaca (The Desert
Date) in Uganda, Borassus aethiopum (African Fan Palm) in Sudan,
Cordeauxia edulis (Yehib) in Ethiopia, Sclerocarya birrea
(Marula) in Tanzania, and Vitex payos (Chocolate Berry) in Kenya.
This report presents the results of the second year achievements
of the project. The project activities are well underway and significant
achievements have been made in all the five participant countries.
1. Research achievements made during the
2nd year and plans for 3rd year
The study site in Ethiopia is very close to the border with the neighboring
war-torn Somalia and there are also rebel activities on the road from
Jijiga to the study site (no alternative road). The security situation
around the study area, therefore, remains unstable. However, the researcher
managed to visit the study site twice during the second year of the project
whenever rebel activities were low. He managed to collect the field data
by exploiting to the fullest this window of opportunity.
Preliminary assessment of the phenology study indicated
that Cordeauxia edulis is an evergreen small tree or shrub. It
flowers and fruits twice a year: flowering between March and April and
October and November and fruiting between April and May and November and
December. This is due to two rainy seasons: March to May (140 mm) and
September to November (80 mm) and total annual rainfall is 229 mm. Fruits
were harvested at the end of each fruiting period and yield ranged from
0.2 to 2 kg per tree.
Further analysis of the data on the population survey of C. edulis
revealed that the tree is multi-stemmed and the number of stems per tree
ranged from 11 to 17. Average total height of the tree ranged from 1.40
to 1.95 m, and crown diameter from 1.1 to 2.4 m. The regeneration ranged
from 0 to 4 seedlings per ha.
Tree species that are associated with C. edulis included Acacia
horrida, Acacia tortilis, Balanites scillin, Boswellia neglecta, Boswellia
microphylla, Cassia obovata, Commiphora horrida, Commiphora erytherae,
Commiphora candidula, Cordea africana, Euphorbia cuneata, Fagonia lahavari,
Indogofera ruspolii, Sesamothamnus rivea and Terminalia orbicularis.
The soil of the study site was analysed and the soil
textural class is sandy loam and K, Ca, N and OM were higher under the
tree than outside.
The propagation trails conducted in Jijiga using seeds collected in 2008
showed some success. The highest germination of seeds (50%) was obtained
using soil obtained from the study site. The second experiment in which
seeds were pre-treated by socking in alcohol for ½ an hour then
washing them with distilled water showed that the rate of germination
was enhanced, the highest percentage being (60%) which was achieved in
soils from the study site.
The results of a post-harvesting experiment carried out
to identify improved methods of harvesting and storage showed that seeds
harvested after drying on the tree and then treated with Neem leaves as
herbicide before storage were not attacked by pests while seeds that were
harvested fresh and stored without herbicide were fully attacked by pests
by the end of 10 weeks of storage as reported by 89% and 97% of the research
participants (local people), respectively.
Another experiment on propagation is planned for the
3rd year. This will involve application of different watering regimes
(watering twice a day, once a day, two days interval and three days interval),
combined with pre-treatment of seeds (socking in acid and control without
pre-treatment) and shading (under full shade, partial shade and a control
Fruit yield per tree of Vitex payos in Kenya was assessed by
counting all fruits on a tree before the fruits ripened and started falling
on the ground. For this, two methods were used; 1) counting all fruits
on a tree and 2) randomly sampling of some branches and counting the fruits
on those branches. The results indicated that trees with many main branches
and of high diameter produced fewer fruits. Trees with many secondary
branches but of small diameter and few main branches produced more fruits.
The amount of pulp that could be realized from a given
quantity of fruits was also assessed. The mean pulp weight is 48.3% of
the total fruit weight. Estimation of the fruit numbers using random branch
sampling method is planned for the 3rd year.
Superior quality trees were selected using local people’s selection
criteria to supply the scions needed for the grafting work and cuttings
for vegetative propagation trials. For the grafting work seedlings were
raised in the nursery to be used as rootstocks. These seedlings were grafted
using scions collected from the selected superior mother trees.
Out of the 81 nursery grown rootstocks that were grafted, only 24 were
successful using top wedge grafting technique. Out of the 24 successful
grafts, three produced flowers while still in the non-mist propagator.
These grafts were removed from the non-mist propagator and planted in
the field. Their performance is being monitored.
The grafting trial using naturally regenerated wildlings as rootstocks
in the field was not carried out because the wildings were small and scattered
to allow proper setting up of a grafting trial among them.
Four trials were carried out on cuttings of V. payos
using rooting enhancing chemicals, different rooting medium, different
mother trees and different heights on the mother tree where the cuttings
were obtained from. None of the cuttings rooted. The trial shall be repeated
every month next year to determine if there is an appropriate time when
cuttings should be collected from the field.
The market surveys revealed that in Mwingi and Kitui
districts, V. payos fruits are not only locally consumed but
are also sold in the local markets. The marketing of these fruits is a
haphazard process with prices varying from place to place. A 20 litres
bucket of fruits normally sells for between 80 and 150 KES (£1 =
KES 113) in Ikanga and up to 200 KES in Kalundu market, Kitui. However,
the same quantity of fruits in Mwingi sells for between 25 to 100 KES.
The market survey also revealed that no processing of
V. payos fruits has been done by local prople, safe for some
minor attempts by children to make some juice. To raise awareness on the
potential of these fruits, the preparation of V. payos jam was
demonstrated in public in all the study areas. The emphasis was to inform
the farmers that with only a single external input, sugar, it was practically
possible to prepare the jam as a means of adding value to the tree. The
most challenging step in the whole process is the separation of pulp from
the nuts. Using local artisans, a potato peeler is being modified to operate
manually to separate the pulp from the seeds. This equipment shall be
demonstrated on the farms during the 2009 fruit season between April and
Halook is one of the main products of Borassus aethiopum. These
are young shoots that are grown traditionally by sowing seeds of B.
aethiopum on mounds. The young shoots are eaten after cooking as
a delicacy and are extensively traded on local markets.
Halook was grown in the nursery using the same traditional mounds for
six weeks and its nutritional properties were analysed at weekly intervals
and the results showed that the highest quantity of crude protein (40.41%)
and fibre (36.69%) were obtained by the end of 6 weeks of growth.
B. aethiopum were intercropped with cowpea and sorghum using
trees of different ages (young & mature) and different planting spacing
(one, two and three meters from the base of the tree). Age of tree did
not have effect on the yield of crop. But distance had significant effect,
the highest yield of crop being close (1m) to the base of the tree: 1.39
and 2.98 tons per ha for sorghum and cowpea, respectively. The yield of
sorghum outside the tree crown (control) was, however, higher than under
shade, in contrast to cowpea. This may be due to difference in shade tolerance.
The results of soil analysis of the study sites showed
that the textural classes of the top soil (0-15 cm) were sandy clay in
two sites and sandy loam in one site and the organic matter content ranged
from 0.19 to 0.46 ml per litre and pH from 7.02 to 7.16.
An experiment to test improved techniques of growing
B. aethiopum has been established in the nursery. The following
seed pre-treatments were applied: (1) boiling, (ii) soaking in cold water,
(iii) scarification, and (iv) nipping. A potting mixture of sand and clay
at the ratio of 2:1 was used and farm yard manure was added to the mixture.
These treatments were arranged in split plot design with three replications.
Assessments of germination and seedling development are ongoing.
Data collection and analysis on population status, phenology,
local knowledge and market surveys are also ongoing.
Using local peoples’ criteria, 20 superior mother trees of Sclerocarya
birrea were selected from which cuttings were obtained for vegetative
propagation experiment. After the vegetative propagation experiment the
rooted cuttings were supposed to be used as rootstocks for grafting of
scions from the selected superior mother trees of S. birrea.
The vegetative propagation experiment was conducted using cuttings obtained
from distal parts of branches of the mother trees in a non-mist propagator,
but was not successful. Air-layering technique was also applied, but the
air-layers failed to root. After consultation with experts from ICRAF
and the project supervisors it was decided to abandon the cutting and
air-layering experiments. A similar experiment done by ICRAF in 2000 to
2003 resulted in similar results.
The propagation trial is now focusing on grafting of both male and female
scions from selected superior mother trees onto naturally regenerated
seedlings in farmers’ fields using two methods of grafting, namely
top vs whip & tongue grafting, on different sizes of rootstocks (wildings).
The results are positive and success has been almost 99% so far. The performance
of the grafts is being monitored by assessing changes in leaf number and
colour and increase in length of the grafted scions.
Questionnaire survey to illicit local knowledge on use
and management of S. birrea has been done and data analysis is
underway. Soil samples have been collected from each site and analysis
is being done at Morogoro. Total direct fruit counting and measurement
of weight and size of fruits are being done in all the three sites. Laboratory
analysis of the nutritive properties of the fruits will be done at Morogoro
and Bangor. Phenological assessment is also ongoing.
Four Balanites aegyptiaca populations have been inventoried.
Preliminary results showed that in both study sites (Ajumani and Katawi
districts) there are generally more B. aegyptiaca trees in the
wild than on farm. The average stocking density was 9 and 3 trees/ha in
Ajumani and Katawi, respectively. Tree diameter at breast height ranged
from 10 cm to 90 cm. Tree height ranged from 2 to 15 m while crown diameter
varied from 1.5 to 22 m. Diameter class distribution revealed fewer trees
in the lower (10 – 19 cm) and higher (>54 cm) diameter classed
but more trees in the mid diameter classes 20 – 34 cm, 35 –
44 cm, and 45 – 54 cm. This shows a low recruitment of saplings
into trees. Crown diameter is generally larger for Adjumani tree populations
than those in Katakwi. This can be explained by the repeated lopping of
trees in Katakwi to provide a leafy vegetable. 70% of the trees in Katakwi
have been looped to obtain a leafy vegetable. B. aegyptiaca was
found to regenerate by both seed and coppicing. In both study sites, B.
aegyptiaca was found to be the most dominant species. It was more
abundant in Adjumani district where it constituted over 72% and 58% of
the tree vegetation in the wild and on farm, respectively. In Katakwi
district, Balanites constituted 40% and 42% of the tree population in
the wild and on farm, respectively. In Adjumani district, B. aegyptiaca
was commonly associated with Lannea schwenfurthii, Tamarindus indica,
Acacia sieberiana, Sclerocarya birrea, Combretum collinum and Zyzyphus
abyssinica. In Katakwi district it was commonly associated with Combretum
schumanii, Acacia sieberiana, Acacia seyal, Acacia gerrardii, Euphorbia
candelaberum, Lannea barteri and Tamarindus indica.
The results so far collected on phenological events for
B. aegyptiaca indicated that it is a semi-deciduous tree. Flowering is
initiated around January and reaches a peak in Feb-March. Fruiting starts
around February and the fruits are fully developed after 7 - 9 months.
Fruit repining sets in around November, reaches a peach in December –
January and ends in late March.
Assessment of the cutting experiment in the non-mist propagation experiment
showed that 11% and 16% of the stem cuttings rooted in the sand and pine
bark growth media, respectively, after ten weeks.
All the cuttings which rooted were transferred into a standard transplant
soil mixture in polythethene tubes and kept at 75% shade green house.
Although they were watered trice daily, all the plants, however, dried
up after two weeks. Grafting using one year old B. aegyptiaca
seedlings raised from seed in the nursery as rootstocks was, however,
not a success. Grafting experiment will be repeated during the wet season
(April - May 2009).
The results of the germination experiment using various seed pre-treatment
techniques and conducted in a green house showed that there is probably
no need for B. aegyptiaca seed pre-treatment. After two weeks observation,
no germination was recorded under pre-treatment (i) boiling for 10 minutes
and left to cool in water for 4 hours, 62.5% under treatment (ii) soaking
in cold water at room temp for 24 hours, 59.5% under treatment (iii) soaking
in hot (boiling) water for 12 hours, and 63% under treatment (iv) sowing
in pots without any treatment (control).
Activities undertaken under on-farm experiment on the management of B.
aegyptiaca seedlings including routine weeding and manure application
at six monthly intervals did not enhance the growth rate of seedlings,
the maximum height being only 80 cm. The growth nature of the plant, dying
of the leading stem and re-sprouting of several stems is a challenge in
growth monitoring. Livestock browsing, especially by goats has also been
Data entry and analysis on the marketing study is currently on-going.
Nutritional analysis of leaves and fruits of B. aegyptiaca with
supplementary funding from Makerere University (Carnegie Institutional
Development Program) are also underway and are planned to be completed
by June 2009.
A seminar on C. edulis was given at Somali Region Pastoral and
Agro-pastoral Research Institute (SoRPARI), Jijiga to scientists and technicians.
A 40 minute documentary on the species was broadcasted on Somali programme
of the Ethiopian Television. A newspaper article has also been published
in a local Somali language newspaper, Dhamball, Page 6.
An article on V. payos has been published in a national newspaper,
The People Daily, Page 14.
Two Seminars on B. aethiopum were given: one at El Obeid Research
Station and the second at the Forestry Research Centre in Khartoum to
scientists and technicians. An article has also been published in a national
newspaper, The Citizen, Page 19.
An article on S. birrea has been published in a national newspaper,
Daily News, Page 9. It is also available online at:
An article on Balanities has been published in a national newspaper, Sunrise,
Two seminars were given. One was at Katakwi district
council hall to members of the District Environment Committee, Heads of
Natural Resources-based Departments, and NGO representatives. The second
was at Adjumani district council hall to the District’s Heads of
Departments, Sub-county representatives, NGO representatives and the Chief
Administrative Officer. The extracts of the Adjumani seminar were aired
out on local radio. The major outcome of both seminars was the issuance
of Tree Planting and Protection Ordinance and Environment and Natural
Resources Protection Ordinance in Katakwi and Adjumani, respectively.
A third seminar was given at the National Forestry Resources Research
Institute, Mukono to research scientists and technicians.