Pearl millet (Pennisetum glaucum) is the most widely grown type of millet in Africa and Asia. Pearl millet is well adapted to growing in areas characterized by drought, low soil fertility, and high temperature. It grow well in soil with high salinity or low pH. In northern Namibia, pearl millet grains are stored in wooden, plastic and cement containers for future consumption and also seeds for the next planting season. This study looked at viability, germination and sugar content of pearl millet grains in different containers after 0-16 months post-harvest. Germination and viability of pearl millet grains decreased as the period of storage increased, and this was more obvious especially in cement and wooden containers. Viability in wooden container ranged between 64-50% after 8-16 months post-harvest compared to 83-74% in plastic container and 30-12% in wooden container after a similar period of storage. Pearl millet grains were found to contain high amounts of starch and sucrose for the first four months and it decreases as storage time increase. As the duration time of storing the pearl millet grain increased, the amount of starch and sucrose decreased. This happened in all storage containers but there was a rapid loss in starch and sucrose content in cement storage than in the other storage facilities. Article Citation: Marius Hedimbi, Natalia K. Ananias and Martha Kandawa-Schulz. Effects of storage conditions on viability, germination and sugar content of pearl millet (Pennisetum glaucum) grains. Journal of Research in Agriculture (2012) 1: 088-092. Full Text: http://www.jagri.info/documents/AG0018.pdf

1. Effects of storage conditions on viability, germination and sugar content of
pearl millet (Pennisetum glaucum) grains
Keywords:
Pearl millet, viability, germination, storage container, storage period, sugar
content, post-harvest.
ABSTRACT:
Pearl millet (Pennisetum glaucum) is the most widely grown type of millet in
Africa and Asia. Pearl millet is well adapted to growing in areas characterized by
drought, low soil fertility, and high temperature. It grow well in soil with high salinity
or low pH. In northern Namibia, pearl millet grains are stored in wooden, plastic and
cement containers for future consumption and also seeds for the next planting
season. This study looked at viability, germination and sugar content of pearl millet
grains in different containers after 0-16 months post-harvest. Germination and
viability of pearl millet grains decreased as the period of storage increased, and this
was more obvious especially in cement and wooden containers. Viability in wooden
container ranged between 64-50% after 8-16 months post-harvest compared to
83-74% in plastic container and 30-12% in wooden container after a similar period of
storage. Pearl millet grains were found to contain high amounts of starch and sucrose
for the first four months and it decreases as storage time increase. As the duration
time of storing the pearl millet grain increased, the amount of starch and sucrose
decreased. This happened in all storage containers but there was a rapid loss in starch
and sucrose content in cement storage than in the other storage facilities.
088-092 | JRA | 2012 | Vol 1 | No 1
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Journal of Research in
Agriculture
An International Scientific
Research Journal
Authors:
Marius Hedimbi1
,
Natalia K. Ananias1
and
Martha Kandawa-Schulz2
.
Institution:
1. Department of Biological
Sciences, University of
Namibia, P/Bag 13301,
Windhoek, Namibia.
2. Department of Chemistry
and Biochemistry,
University of Namibia,
P/Bag 13301, Windhoek,
Namibia.
Corresponding author:
Marius Hedimbi..
Email:
mhedimbi@unam.na/
mhedimbi@yahoo.com.
Phone No:
(+264) (61) 206 3425.
Fax:
(+264) (61) 206 3791.
Web Address:
http://www.jagri.info
documents/AG0018.pdf. Dates:
Received: 01 Feb 2012 Accepted: 09 Feb 2012 Published: 16 Jun 2012
Article Citation:
Marius Hedimbi, Natalia K. Ananias and Martha Kandawa-Schulz.
Effects of storage conditions on viability, germination and sugar content of pearl millet
(Pennisetum glaucum) grains.
Journal of Research in Agriculture (2012) 1: 088-092
Original Research
Journal of Research in Agriculture
JournalofResearchinAgriculture An International Scientific Research Journal

2. INTRODUCTION
Pearl millet (Pennisetum glaucum) is a
traditional staple food crop of the semi-arid tropical
zones of Africa and Asia, and it is cultivated in areas
with a rainfall ranging from 150 mm to 800 mm per
annum. It has a high nutritional value compared to other
cereals like maize, wheat or rice, it is digested more
slowly and thus delays hunger, it has a higher lipid and
protein content, and its amino acid balance is better than
that of other cereals (Labetoulle, 2000). Pearl millet is
one of the most drought tolerant cereals and can grow in
soil with low fertility which is unsuitable for other
cereals. Being particularly resistant to moisture stress
and adapted to high temperatures, it has a low yield,
which also explains its high nutritional value compared
to other cereals. In the dryer parts of Southern Africa
(Angola, Namibia, Zimbabwe, Botswana, Zambia and
South Africa) pearl millet is traditionally grown as a
staple food crop (Mallet and du Plessis, 2001).
Pearl millet is a principal source of energy,
protein, vitamins, and minerals for millions of people in
the regions where it is cultivated as the dominant crop
(Hulse et al., 1980). Pearl millet, like sorghum, is
generally composed of 9-13% protein but large
variations in protein content, ranging from 6-21%, have
been observed (Baker, 2003). Pearl millet grains are
usually made up of 70% carbohydrates and consist
almost exclusively of starch. The starch itself is
composed of two third amylopectin and one-third
amylase (USAID, 1971). It has no husk, no tannin,
contains 5-7% oil, and has higher protein and energy
levels than maize or sorghum. Pearl millet is also rich in
B vitamins, potassium, phosphorus, magnesium, iron,
zinc copper and manganese (Baker, 2003).
Pearl millet is the most important cereal crop in
Namibia and over 60% of Namibia population depends
on it as their staple food (Ipinge, 1998). It is widely
grown in seven regions of Namibia such as Caprivi,
Kavango, Oshikoto, Ohangwena, Oshana, Omusati and
Kunene covering about 355200 hectors of land (Ipinge,
1998). In Namibia more pearl millet are produced
annually, and the farmers store pearl millet till the next
rain season. A number of storage facilities are used to
store pearl millet in Namibia (Goussault and Adrian,
1977) such as wood containers, cement buildings, and
plastic containers. Pearl millet stored in some of the
facilities such as cement and wooden containers have
been observed to have deteriorated in their physical
appearance, mainly due to pest invasion. However it is
not clear if these reductions in physical appearance also
translate into reduced viability, germination and sugar
content of the grains. Therefore this study was conducted
to find out the effect that different storage facilities have
on viability, germination and sugar content of pearl
millet grains after various period of storing the grains
post-harvest.
MATERIALS AND METHODS
Sample collection
Pearl millet grain samples were collected from
the northern part of Namibia, in the Omusati region
(Oikokola village), Ohangwena region (Endola village)
and Oshikoto region (Omupupa village). Samples were
collected every four months for 16 months post-harvest.
Three samples from each storage facility from each
village were collected. Samples that were not used
immediately were kept in plastic containers and stored at
4ºC in the dark until use.
Viability test
The method for viability test was modified from
that reported by Pelah et al., (2003). Ten pearl millet
grains from each storage facility were soaked in water
for 24 hours at room temperature to allow hydration and
initiate the germination process. Grains were then placed
in different petri dishes and covered with 1% of
2,3,5-triphenyltetrazolium chloride (TTC) solution. The
petri dishes were closed and covered with aluminium foil
and left in the TTC solution for 24 hours and the viability
089 Journal of Research in Agriculture (2012) 1: 088-092
Hedimbi et al., 2012

3. of the seeds were observed after 24 hours. Viable seeds
appeared pink to red inside.
Germination test
Plastic pots were filled with the growth media
(vermiculate). Twenty seeds from each facility were
sown per pot. The grains were watered every 2 days for
about three weeks and their ability to germinate was
recorded.
Starch test
Pearl millet grains were ground to fine powder
using the mortar and the pestle. The grounded powder
was placed in petri dishes. Approximately 1mL of iodine
solution was added to each petri dish. A dark blue colour
indicates the presence of starch.
Sucrose test
Pearl millet grains were ground to fine powder
using the mortar and the pestle. About 3g of fine powder
was transferred into different test tubes. About 5mL of
water was added to each test tube, and the test tubes were
swirled to mix the flour and water. About 5mL of
Benedict’s reagent was added to each test tube and the
test tubes were heated to boil in a water bath for few
minutes. If the solution turns green it indicates the
presence of sucrose.
RESULTS
Effects of storage facilities and duration on viability
and germination
In general, grains in storage facilities lost their
viability and germination chances as the duration of
storage post-harvest increases. The cement storage
container shows a rapid decrease of viability and
germination, especially between four and eight months
(Figure 1). Viability in wooden container ranged
between 64-50% after 8-16 months post-harvest
compared to 83-74% in plastic container and 30-12% in
wooden container after a similar period of storage. After
16 months post-harvest, viability and germination
remained high in plastic container (about 80%) compared
to cement container (less than 20%) and wooden
containers (20% germination and 60% viability)
(Figure 1).
Starch and sucrose content in pearl millet
As duration of storage increased, starch and
sucrose levels decreased in all storage containers. In
cement container, there was no sucrose detected after 16
months post-harvest. Starch and sucrose content was
better in the plastic and wooden storage facilities then in
the cement facilities from 8-16 months of storage
(Table 1).
DISCUSSION
Germination and viability of pearl millet grains
decreased as the period of storage increased, and this was
more obvious especially in cement and wooden
containers. There was a rapid loss of viability and
germination in the cement storage facility after four
months of storage and germination was less than 5%
after 16 months of storage in cement (Figure 1). The
rapid loss of viability and germination in cement can be
attributed to pest degradation due to the high pest
infestation associated with this storage facility. The level
of moisture content in the cement is likely to be high
compared to other storage facilities and might have
caused an increase in the amount of pest which in turn
Journal of Research in Agriculture (2012) 1: 088-092 090
Hedimbi et al., 2012
Figure 1: Viability and germination of pearl millet
grains in different storage containers after 0-16
months post-harvest.

4. would have resulted in low viability and germination in
the cement facility. Change in climate conditions has
been implicated as one of the reasons for increase in crop
pests by farmers in Rongai district, Kenya, in a study by
Ngeno et al., (2011). The main reason why farmers
regards pest infestation as the main reason for reduction
in agricultural output could be explained by the damage
and losses caused by different pests within a short period
(Ngeno et al., 2011).
Viability was higher than germination in all
storage facilities and this might be an indication of low
correlation between viability and germination, which
means not all viable grains are capable of germination. It
is possible that the low germination observed in this
study might be attributed to the artificial growth medium
(Vermiculate) used. However, no negative effect of the
growth medium used on germination has been reported
in the literature.
Pearl millet grains were found to contain high
amounts of starch and sucrose for the first four months
and it decreases as storage time increases. As the
duration time of storing the pearl millet grain increased,
the amount of starch and sucrose decreased. This
happened in all storage containers but there was a rapid
loss in starch and sucrose content in cement storage than
in the other storage facilities. Starch and sucrose content
remained better in plastic facility with medium (++)
amount after 16 months of storage compared to other
storage facilities which had low to no presence after the
same period of storage (Table 1). This study has shown
that pearl millets are rich in starch and sucrose. In a
similar study by Hulse et al., (1980), high amounts of
starch were found in sorghum and millets grains.
Plastic storage facility was the best in preserving
the grain qualities studied, but it is likely to be good at
absorbing heat which will cause proteins to change from
one form to another (Boora and Kapar, 1985).
Adu-Amankwa and Boateng (2011) carried out a study
on the postharvest loss of plantains (Musa spp. AAB,
ABB) in selected markets in Ghana and suggested that
high temperatures are likely to cause withering of
products due to high transpiration and respiration. The
study revealed that cement is not a good container to
store pearl millet grains as it results in significant loss of
viability, germination, starch and sucrose as compared to
other facilities. The high level of pest infestation, which
eats the inner core of the grains, is likely to be the cause
of loss of grain quality observed in this study.
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Adu-Amankwa PA and Boateng BA. 2011. Post-
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091 Journal of Research in Agriculture (2012) 1: 088-092
Hedimbi et al., 2012
Cement Wooden Plastic
Duration of storage (months) Starch Sucrose Starch Sucrose Starch Sucrose
0 (control) +++ +++ +++ +++ +++ +++
4 +++ +++ +++ +++ +++ +++
8 ++ + +++ +++ ++ +++
12 + + ++ + ++ ++
16 + - + + ++ ++
Table 1. Starch and sucrose content in pearl millet grains in different storage containers 0-16 months
post-harvest. +++=strong presence; ++=moderate presence; +slight presence; - = not detected.
Figure 2: Germination of pearl millet grains after 12
months post-harvest in different storage containers.
From left to right: Cement, traditional and plastic
storage containers.

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