Enhancing Productivity and Production of Onion (Allium cepa L.) Through the use of Improved Varieties at North Western Zoze of Tigray, Ethiopia

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International Journal of Environment, Agriculture and Biotechnology (IJEAB) Vol-3, Issue-3, May-June- 2018
http://dx.doi.org/10.22161/ijeab/3.3.6 ISSN: 2456-1878
www.ijeab.com Page | 756
Enhancing Productivity and Production of Onion
(Allium cepa L.) Through the use of Improved
Varieties at North Western Zoze of Tigray,
Ethiopia
Gebremedhn Gebretsadkan, Yohanes Gebremicael, Kiros Asgele, Eyasu Abebe,
Weldegerima Gebrelibanos, Yrgalem Tsehaye
Tigray Agricultural Research Institute (TARI)
Shire-Maitsebri Agricultural Research Center (SMARC)
Abstract Field experiment was conducted to study the
effect different varieties on yield, yield attributing character
and postharvest storability of onion (Allium cepa L.) in
Tselemti district, North western Zone of Tigray During 2007-
2009off season time. Four improved onion varieties
namly:Bombey red, Adama red, Nasik red &Nafis includ ing
Shendi (imported from Sudan),were tested in Randomized
Complete Block Design (R CBD) with four replica tions.
Accordingly, treatments were assigned randomly to the
experimental plot within a block. The results showed that the
difference in variety had significan t effect on all characters
except the non-significant effect of variety on neck thickness
and bulb diameter. Nasik red variety gave
significantlyhighest in plant height ,leaf number, leaf length
bulb length and marketable bulb yield i.e 35588kg/ha that
exhibited 18% and 36% advantages on the dominantly
produced varieties bombey red and adama red
respectively.The overall study revealed that growing Nasik
red variety is not only significantly increased the marketable
bulb yield , but also better shelf life. Therefore, it is
recommended for onion producers of Tselemti wereda for
profitable onion yield
Key words Onion, Storability, Variety, Yield.
I. INTRODUCTION
Onion (Allium cepa L.) is an important bulb crop, belonging
to the family Alliaceae (Hanelt,1190).It is one of the most
important and popular bulb crops cultivated commercially
in nearly most parts of the world. Onions as food, medicine
and religious object were known during the first
Egyptian dynasty (3200 B.C.) (Ray and Yadav, 2005). ).
It is important in the daily diets of human’s in worldwide and
Ethiopians as well (MoARD, 2006). Onion contributes
significant nutritional value to the human diet and are
primarily consumed for their d istinctive flavor widely used
in soups, meat dishes, salads, food dressings and sandwiches,
medicinal purposes and is cooked alone as a vegetable. It s
pungency is due to the presence of a volatile oil (Allyl propyl
disulphide) (Malik, 1994).
Onion (Allium cepa L.) is a recently introduced bulb crop in
the agriculture co mmodity of Ethiopia and it is rapidly
becoming a popular vegetable among producers and
consumers (Lemma and Shimeles, 20 03; Dawit et al., 2 004).
It is more widely grown in Ethiopia for local consumptio n
and for flower export (Lemma and Shimeles, 2003). It is
valued for its distinct pungency or mild flavour and
also consumed universally in small quantities and used in
many homes almost daily, primarily as a seasoning for
flavouring of dishes, sauces, soup, and sandwiches in many
countries of the world (Geremew et al., 2010).
Onion is one of the most important vegetable crops in
Ethiopia which is used almost daily as a spice an d
vegetable in the local dish regardless of religion, ethnicity,
and culture (CSSE, 2006). The diverse agro-climatic
conditions that prevail in the country provide the opportunity
of producing onion bulb, seeds and cut flower for local use
and export market (CSSE, 2006). Additionally, its higher
yield potential, availability of desirable cultivars for
various uses, ease of propagation by seed, high domestic
(bulb and seed) and export (bulb, cut flowers) markets in
fresh and processed forms is making the crop
increasingly important in Ethiopia (Yohannes,1987).
Ethiopia has enormous potentials to cultivate the vegetable
crops at small as well as lar ge commercial scale. The
International Journal of Environment, Agriculture and Biotechnology (IJEAB) Vol-3, Issue-3, May-June- 2018
http://dx.doi.org/10.22161/ijeab/3.3.6 ISSN: 2456-1878
www.ijeab.com Page | 757
country has high potential to benefit fro m onion
production, and the d emand for onion is increasing from
time to ti me for its high bulb yields, seed and flower
production potential (Lemma and Shimelis, 2003).Statistics
indicated that, the production of onion in Ethiopia during
2012/2013 growing season was in about 21865ha of land
yielding a total production of 219919 tons with an average
yield (10.06 tons /ha) which is too low as compared to the
world average of 19.31 tons/ha (FAOSTAT,2013).
There are a number of constraints that cause low
productivity of onion in Ethiopia. The low yield of onion
in the country is reported to be due to low fertility of soil,
inappropriate fertilizer rate, lack of improved varieties, and
poor management practices (Lemma and Shimelis, 2003).
The use of proper agronomic practice has an undoubted
contribution in increasing crop yield. The optimum level
of any agronomic practice like plant spacing, p lant
population, planting date, harvesti ng time can bring desired
results. The optimum use of spacing or plant population has
dual advantages. It also avoids strong competition
between plants for growth factor such a s water, nutrient
and light. Co nversely,optimum plant population enables
efficient use of available crop land without wastage
(Zubelidia and Gases, 1977).
The use of app ropriate agronomic management practices
is important to increase the productivity and production of
the crop. However, in the country, intra-row spacing of 10
cm and inter-row spacing of 20 cm during transpla nting to
permanent field is used which was recommended before 20
years (FAO, 1995). But, plant spacing as an important
economic consideration in the production of onion should
have to depend on type of variety (plant architecture, gro wth
habit etc.), agro-ecology, production system etc. Therefore,
for onion production, it is very difficult to give ge neral
recommendation to be applied uniformly in all agro
ecologies of the country (UAAIE, 2001). Gupta et al.
(1994) and Lemma and Shimeles (2003) suggested that to
optimize onion productivity, full package of information is
required for each growing region of the country.
Similarly, the success of onion prod uction is also depend on
soil nutrients. Different levels of nutrients affect the yield
and taste of the bulbs even within a variety.Application of
nutrients play a major role in increasing productivity of
onion. Onions are weaker than most other crop plants in
extracting nutrients from the soil, especially the immobile
types because of their shallow and unbranched root system;
hence t hey require and often respond well to addition of
fertilizer (Brewster, 1994) . Nitrogen and phosphorus are
often referred to as the primary macro nutrients because of
the probability of plants being deficient in these nutrients and
because of large quantities taken up from the soil
relative to other essential nutrients(Marschner, 1995).
Generally, there are a number of constraints that cause
low productivity of onion in Ethiopia. The low yield of
onion in the country is reported to be due to low fertility of
soil, inappropriate fertilizer rate, lack of improved varieties,
and poor management practices (Lemma and Shimelis,
2003). Among these constraints, inappropriate use of mineral
fertilizers, lack of improved and adaptable varieties and un
proper plant spacing are the most limiting factors in our
mandate areas.
Therefore the present study was conducted with general
objectives of identifying ad aptable onion varieties, assessing
the effects of nitrogen and phosphorus fertilizer rates and
different inter and intra row spacing on growth, yield and
yield components of onion in the study area.
Objective
To investigate the performance of different varieties
of onion & identify the best agro ecologically
adaptive, high yielder and disease resistance onion
varieties to the area
II. METHODOLOGY
The experiment was conducted at Tselemti Wereda Shire-
Maitsebri (SMARC) experimental Station during 2007-
2009E.c off season periods. Four improved onion varieties
namly: Bombeyred, Adamared, Nasik red & Nafis including
Shendi (imported from Sudan),were evaluated for their yield
performance for the last three years. The field experiment
was laid out in Randomized Complete Block Design (RCBD)
with four replications. Accordingly, treatments were assigned
randomly to the experimental plot within a block.
A plot size of 2 x 3 m (6 m2) was used. The blocks were
separate by 1 .5m, whereas plots within a block were 1m
apart from each other. Each plot consists of 5 ro ws of 3m
length, with a spacing of 40cm between rows & 10 cm
between plants. Reco mmended amount of fertilizer
(200kg/ha DAP & 100kg/ha Urea) were used. All
management practices (ploughing, cultivation, watering,
nursery and transplanting method, weeding and others) were
applied uniformly to all plots as per standard
recommendations for the crop. The experimental area was
kept weed free by hand pulling thro ughout the cropping
season. In addition to the field evaluation, simple postharvest
evaluation also conducted for all the varieties. For this
purpose 6kg representative bulbs were selected from each
International Journal of Environment, Agriculture and Biotechnology (IJEAB) Vol-3, Issue-3, May-June- 2018
http://dx.doi.org/10.22161/ijeab/3.3.6 ISSN: 2456-1878
www.ijeab.com Page | 758
variety and kept under normal storage condition to compare
their storability.
Method of Agronomic Data Collection
All data relating to yield and yield components were
collected from the central th ree r ows b y excluding plants
from either end of the rows. For the p urpose of crop data
collection two (2) plants/row or six(6) plants/plot were
selected randomly from each plot and ob servations on
growth, yield and yield components of the crop such as: plant
height, average leaf length, average leaf number, average
neck thickness, average bulb len gth, diameter &yield were
recorded.
Plant height (cm): Plant height was measured from the
ground level up to the tip of the
Longest leaf using ruler. Plant height of sex rando mly
selected plants were measured in the
central rows of each plot at physiological maturity stage
of the crop and the average was
Computed.
Days to physiological maturity: It was registered on plot
basis as the actual number of d ays from date of transplanting
to when about 75% of t he leaves fell down and 2/3 leaves
had turned yellow
Number of leaves per plant: The number of fully developed
leaves of six randomly selected plants was counted at the
active green leaf stages and the average was computed to
obtain number of leaves per plant.
Leaf length (cm): Leaf length was recorded as the average
length of the longest leaves in six randomly selected plants at
maturity.
Bulb diameter (cm): Bulb diameter was measured at right
angles to the longitudinal axis at the widest circumference
of the bulb of six randomly selected plants in each plot
using veneer calliper (Saud et al., 2013) at harvest.
Bulb length (cm): Bulb length was the vertical average
length of the matured bulb of six randomly selected plants in
each plot which was measured by veneer calliper.
Bulb neck thickness (cm): The average neck thicknes ses of
six randomly selected plants in ea ch plot were obtained by
measuring the neck of bulbs at the narrowest point at the
junction of bulb and leaf sheath using a veneer calliper.
Marketable bulb yield (t /ha): Marketable bulb yield was
determined after discarding the unmarketable bulb, weight
healthy bulbs and having nationally accepted marketable
bulb weight of 60 g (Tegbew, 2011) at harvest in each plo t
and converted to t /ha.
For postharvest evaluation six kg of onion from each variety
were weighed and stored in a conventional storage room.
Weight loss and number of sprouted bulbs were reco rded in
every two weeks for about 3months, then finally at the end
of the 3rd month weight and number of un sp routed bulbs
were recorded and tried to compare the storability of each
variety.
Method of Data Analysis
All crop data collected in this study were subjected to two
way statistical analysis of variance (ANOVA) following a
procedure appropriate to a randomized co mplete block
design as suggested by (Gomez and Gomez, 1984).When the
treatment were significant, least significance differences
(LSD) by Dunken’s multiple range comparison were used
for mean separation at p=0.05.
III. RESULTS & DISCUSSION
The data in (Table 1&2)showed a significant (p<0.05)
variability between the varieties in most of the traits.
Days to Bulb Maturity
Days to maturity was significantly (P < 0 .05) influenced by
variety. Bombay Red and Shendi matured significantly
earlier than the ot her varieties at ab out 124.9 & 127 and the
next variety at about 134.2 days, whereas Nasik variety
matured in about 16.8 days later than Bombey red (Table -
1). The variation of maturity among onion varieties might be
due to their genetic differences. Bombay Red variety was
found to be the earliest,which matured 23 days earlier than
Adama Red followed by Melkam which was earlier by 18
days than the Adama Red (Yemane et al., 2014).Similarly
Azoom et al. (2014) also reported significant differences
among eight onion varieties for days to bulb maturit y.
Bombay Red and Adama Red matured b y less than 120
or/and in between 110 to 130 days, respectively (EARO,
2004).
Leaf Length
The analysis of variance revealed a significant (P < 0.05)
effect of variety on leaf length. Both Nasik Red and Adama
red showed the highest mean leaf length (40.27cm &
39.25cm) .Nasik red had significantly higher leaf length by
about 12.2% than Bombay Red(currently dominant variety in
the testing area (Table -1). The difference of varieties in leaf
length might be due to their differences in genetic makeup. In
agreement with the current result, Yemane et al. (2014)
reported that Adama Red (40.75 cm) showed higher leaf
length than Melkam (37.83 cm) and Bombay Red (35.17
cm). Similarly, Mondal et al. (1986), Ghafoor et al. (2003)
and Jilani et al. (2010) also reported the differences among
cultivars with respect to leaf length.