Genetics studies of coffee wilt disease (CWD) and related traits provide valuable evidence in designing appropriate breeding programs and CWD resistant variety development. The use of CWD resistant varieties is the most cost-effective, economical and eco-friendly method for the management of the disease. It is also relevant to smallholder coffee producers or farmers. The study was conducted to evaluate and select promising CWD resistant genotypes, to estimate the genetics of traits and determine the correlation among traits. It was conducted in RCBD with three replications in17 coffee genotypes using artificial seedling inoculation test at the green house, Jimma Agricultural Research Center (JARC). The analysis of variance showed highly significant differences (p<0.01) among the genotypes for wilted seedling percentage, incubation period, number of defoliated leaves and all seedling growth characters (height, stem diameter, average inter node length, petiole length, leaf area, number of nodes and leaves). The overall mean performance showed that genotypes 279/71 and Feyate (971) recorded 6.84% and 8.60% wilted seedling percentage (resistant), respectively; followed by Odicha (974) and 79233. The wilted seedling percentage also showed high broad sense heritability coupled with high genetic advance as percent of the mean (GAM). The study is well done and identified promising CWD resistant genotypes, which should be further study on multi-location (field condition) and also evaluated for yield, other major diseases and important traits.

1. Evaluation of Promising Coffee Wilt Disease (Gibberella xylarioides) Resistant Arabica Coffee (Coffea arabica L.) Genotypes in Ethiopia
IJPBCS
Evaluation of Promising Coffee Wilt Disease (Gibberella
xylarioides) Resistant Arabica Coffee (Coffea arabica L.)
Genotypes in Ethiopia
Admikew Getaneh Yigletu*
Jimma Agricultural Research Center (JARC), Ethiopian Institute of Agricultural Research (EIAR), Ethiopia
E-mail: adamget21@gmail.com
Genetics studies of coffee wilt disease (CWD) and related traits provide valuable evidence in
designing appropriate breeding programs and CWD resistant variety development. The use of
CWD resistant varieties is the most cost-effective, economical and eco-friendly method for the
management of the disease. It is also relevant to smallholder coffee producers or farmers. The
study was conducted to evaluate and select promising CWD resistant genotypes, to estimate
the genetics of traits and determine the correlation among traits. It was conducted in RCBD
with three replications in17 coffee genotypes using artificial seedling inoculation test at the
green house, Jimma Agricultural Research Center (JARC). The analysis of variance showed
highly significant differences (p<0.01) among the genotypes for wilted seedling percentage,
incubation period, number of defoliated leaves and all seedling growth characters (height,
stem diameter, average inter node length, petiole length, leaf area, number of nodes and
leaves). The overall mean performance showed that genotypes 279/71 and Feyate (971)
recorded 6.84% and 8.60% wilted seedling percentage (resistant), respectively; followed by
Odicha (974) and 79233. The wilted seedling percentage also showed high broad sense
heritability coupled with high genetic advance as percent of the mean (GAM). The study is well
done and identified promising CWD resistant genotypes, which should be further study on
multi-location (field condition) and also evaluated for yield, other major diseases and important
traits.
Keywords: Arabica coffee, Heritability, Genetic advanceand Resistant
INTRODUCTION
The global coffee production depends only on two species,
Coffea arabica and Coffea canephora (Labouisse et al.,
2008). Southwestern Ethiopia is the primary center of
origin and genetic diversity for Coffea arabica (Sylvian,
1955; Meyer, 1965; Anthony et al., 2001; Anthony et al.
2002). In 2018/19, world coffee production wasestimated
as10,126.2million kg, with Arabica output, estimated at
6227.4 million kg, accounting for 61% and Robusta,
estimated as3898.8 million kg, representing 39% of the
total.In Africa coffee production was estimated about
1092.36 million kg. Ethiopia shared about 492.6 million
kgand the first producer and exporter in Africa and 5th in
the world (produce 5% of the world and 39 % of sub
Saharan Africa) (ICO, 2019). Arabica coffee shares about
34% of the total exports and 43% of agricultural exports of
the country (Rachel, 2019). Coffee farming alone provides
a livelihood income for around 15 million Ethiopians (16%
of the population), based on four million smallholder farms
(Tefera, 2015).This showed that how much coffee is
important for the Ethiopian economy. However, its
production is low due to traditional coffee production
systems; such as the use of local coffee genotypes, the
widespread and prevalence of diseases, the presence of
abiotic stress and poor agronomic practices (Girma et al.,
2009a).
Coffee berry disease (CBD), coffee wilt disease (CWD)
and coffee leaf rust (CLR) are among the major important
coffee diseases in Ethiopia. Coffee wilt disease (CWD) is
induced by the fungal pathogen Fusarium xylarioides
International Journal of Plant Breeding and Crop Science
Vol. 7(3), pp. 885-893, October, 2020. © www.premierpublishers.org, ISSN: 2167-0449
Research Article

2. Evaluation of Promising Coffee Wilt Disease (Gibberella xylarioides) Resistant Arabica Coffee (Coffea arabica L.) Genotypes in Ethiopia
Admikew Y. 886
(Gibberella xylarioides). Its incidence and severity are 28%
and 5%, respectively (CABI, 2003; Girma et al., 2009a).
There are different techniques used to control CWD, such
as uprooting and burning of infected coffee trees,
prevention of tree wounding, use of protective fungicides
in sealing wounds, use of disease free planting materials,
disinfecting farm implement and use of biological control
(Trichoderma species). Among which the use of resistant
varieties is the most relevant to producers or farmers
(Rutherford, 2006; Phiri and Baker, 2009; Girma et al.,
2009a). Thus, study was conducted to evaluate and select
promising CWD resistant Arabica coffee genotypes for the
future varietal development, to understand the genetics of
traits and the association of them with morphological traits
under diseased condition.
MATERIAL AND METHODS
Description of the Study Area
The study was conducted at Jimma Agricultural Research
Center (in green house) in Jimma Zone of Oromia
Regional State, Southwest Ethiopia. It is found 7o46’N
latitude and 36o E longitude coordinate and at an elevation
of 1753 meter above sea level. It is also located 358
kilometers away from Addis Ababa and 12 kilometer from
Jimma town in the west direction.
COFFEE GENOTYPES AND EXPERIMENTAL DESIGN
Seventeen Arabica coffee genotypes were evaluated for
four CWD parameters and seven seedling morphological
characters (Table 1). The experiment was laid out using
randomized complete block design (RCBD) with three
replications. The growth medium of coffee seedlings was
prepared from heat sterilized and moistened sandy soil.
Forty Coffee seeds of each genotype were soaked
separately in distilled sterile water for about 48 hours after
removing the parchment (Girma and Mengistu, 2000). The
seeds were sown in heat sterilized and moistened sandy
soil in disinfected plastic pots (each pot has 5652 cm3) and
can irrigated with sterile water every one day’s interval to
maintain adequate moisture for seed germination,
emergence and growth. After germination, the seedlings
were thinned into twenty five per pot, out of these, 20
seedlings were used for artificial inoculation test and the
remaining five seedlings were used as a control (non-
inoculated). Five representative inoculated seedlings were
selected from each pot and labeled yellow thread in order
to measure growth characters. The seedlings per pot for
each genotype were inoculated at the fully opened
cotyledon stage (10 weeks old) with a viable conidial
suspension of Gibberella xylarioides by the stem nicking
technique (Pieters and Van der Graaff, 1980; Girma and
Mengistu, 2000).
Table1: Description of Arabica coffee genotypes used for the study
Coffee
genotypes
Origin Breeding method Released/collection
year
Some characters description
75227 Gera, /Jimma Selection from
local
Landraces
1980/81 Open growth habit, good yielder, green tip leaf
color, CBD resistant, susceptible to CWD
(Demelash and Kifle., 2015)
971 Gelana Abaya/
Borena
Selection from
local landraces
2010 Resistant to CWD (Chala et al., 2012)
74110 Metu / Illubabor Selection from
local landraces
1978/79 Resistant to CBD, susceptible to CWD, good
yielder, compact growth habit, green tip leaf
color (Demelash and Kifle., 2015)
8136 Gera/ Jimma Selection from
local landraces
2006 High yielding potential with consistence bearing
habits, resistant to CBD & CLR, vigorous with
intermediate growth habit, stiff stem,
manageable height, moderately resistant to
CWD (Girma, 2004)
79233 Introduce from
France
International
collection
1979 Green tip leaf color, CWD resistant under
natural infested soil (PO under coffee
germplasm conservation at Gera)
74144A Balle/ Oromia Under collection
breeding program
1978/79 Moderately resistant to CWD under natural
infested soil, susceptible to CBD, high quality,
compact growth habit, broth leaf color (PO)
974 Gelana Abaya/
Borena
Selection from
local landraces
2010 Broth tip leaf color, compact growth habit
resistant to CWD (Chala et al., 2012)
370 Seka-Chekorsa/
Jimma
Selection from
local landraces
Resistant to CWD, broth tip leaf color,
susceptible to CBD (Demelash, 2013)

3. Evaluation of Promising Coffee Wilt Disease (Gibberella xylarioides) Resistant Arabica Coffee (Coffea arabica L.) Genotypes in Ethiopia
Catimor
J-19
Introduced from
Portugal
International
collection
1998 Resistant to CWD (Girma, 2004)
Catimor
J-21
Introduced from
Portugal
International
collection
1998 Resistant to CWD (Girma, 2004)
7440 Washi, Kaffa Selection from
local landraces
1979/80 Moderately resistant to CWD (Girma, 2004)
279/71 Sokoru/Jimma Selection from
local landraces
2013 CWD resistant, CBD susceptible (Demelash,
2013)
B-64/04 Balle / Oromia Collection under
breeding program
2004 CWD resistant (Kifle et al., 2015)
B-70/04 Balle / Oromia Collection under
breeding program
2004 CWD resistant (Kifle et al., 2015)
74144B Balle / Oromia Collection under
breeding program
1978/79 Susceptible to CBD, compact growth habit (PO)
Geisha* Introduced from
India
International
collection
2002 Highly susceptible to CWD (Demelash, 2013)
SN-5* Kaffa/ SNNPR Under collection
breeding program
Susceptible to CWD (Girma, 2004)
*= susceptible check, PO= personal observation. Source: JARC / Coffee Breeding and Genetics division database for
genotypes origin, breeding method and some characters description
Data on wilted seedling percentage (at 6 months after
inoculation, was calculated from the cumulative number of
wilted over the total number of seedlings (wilted plus
healthy) based on external symptoms), incubation periods
(the time elapsed from inoculation of the pathogen up to
symptoms expression of each genotype), number of
defoliated and yellow leaves per seedling were collected
for disease parameters. Furthermore, seedling growth
characters such as stem height (cm), stem diameter (mm),
numbers of stem nodes per seedling (NN), number of
leaves per seedling, leaf petiole length (cm), average inter
nodes length on the stem (AINL) and leaf area (cm2) were
measure and computed per tree based on Walyero (1983).
Growth characters were measured from4 months old
seedling based on IPGR (1996) coffee descriptors.
All data were subjected to analyses of variance (ANOVA)
using SAS software version 9.3 (SAS, 2011). Fisher’s
least significant different mean separation test was
performed to identify and compare genotypes. The
phenotypic, genotypic and environmental variances were
estimated based on the method suggested by Singh and
Chaudhury (1985). Broad sense heritability and genetic
advance for CWD and seedling growth characters were
also computed using the formula suggested by (Allard,
1999). The area under the disease progress curve
(AUDPC) was also calculated to quantify the level of the
rate reducing the resistance of genotypes based on Jeger
and Viljanen-Rollinson (2001).
RESULTS AND DISCUSSION
Analysis of variance
Analysis of variance mean squares of 17 genotypes for
CWD and seedling growth characters are presented in
Table 2. The analysis showed highly significant differences
(p<0.01) among genotypes for all CWD characters and the
variability for wilted seedling percentage (Figure 1).
Furthermore, mean squares due to genotypes for all
growth characters showed highly significant (p<0.01).
Coffee genotypes reaction against CWD and seedling
growth characters
The mean performances of 17 coffee genotypes for 11
characters are given in Table 3. It was observed that
wilted seedling percentage, number of yellow leaves per
seedling, incubation period (IP) and seedling height
ranged from 6.84 % to 94.74 %; 0.02 to 1.20; 71 to 155
days;and 7.91cm to 12.34 cm, respectively. Genotypes
279/71 and Catimor J-21 represented the maximum and
minimum mean value of the traits; except for wilted
seedling percentage and number of yellow leaves per
seedling, which were in the reverse direction. Similarly,
seedling stem diameter internodes length, number of
nodes and number of leaves per seedling, petiole length,
leaf area and defoliated leaves per seedling ranged from
1.84cm (Catimor J-19 ) to 2.27cm (7440) ,1.48 (Catimor J-
19 ) to 4.25cm (370), 1.20 and 4.80 (974) to 2.31 and 6.49
(74110), 0.35cm (79233) to 0.50cm (971), 6.41cm2
(Catimor J-19 ) to 11.87cm2 (279/71) and 0.00 (279/71)
to 1.00 (74110), respectively. These data indicated that the
presence of high genetic diversity between genotypes for
the above measured characters (Van der Graaff and
Pieters, 1978; Girma et al., 2009b; Chala et al., 2012;
Demelash and Kifle, 2015; Bayetta, 2001; Olika et al.,
2011).
Genotype 279/71 was the uppermost genotype that
observed desirable characters for most traits; such as for
wilted seedling percentage (low CWD infection),
incubation period, seedling height, seedling stem
diameter, leaf area, the number of defoliate and yellow
leaves per seedling. Genotypes 279/71 (6.84%) and 971
(8.60%) exhibited low wilted seedling percentage coupled
with the longer incubation period, 155 days and 121 days,

4. Evaluation of Promising Coffee Wilt Disease (Gibberella xylarioides) Resistant Arabica Coffee (Coffea arabica L.) Genotypes in Ethiopia
Admikew Y. 888
respectively, followed by 974 and 79233 genotypes.
Moreover, the AUDPC mean result showed significant
variation and progression over time between genotypes
(Figure 2). Low AUDPC mean was calculated for
genotypes 279/71 and 971 similar to wilted seedling
percentage.
Most Arabica coffee genotypes leaves color were changed
to yellow and then, either defoliated or stayed intact3 to 4
months after inoculation starting from older leaves to
younger ones. That means the first true leaves became
yellow; then, either dropped down or wilted without
defoliating and progress to the next true leaves. At the end,
the seedlings were dead completely. This indicated that
genotypes with a greater extent of leaves changed to
yellow and recorded the maximum amount of defoliated or
wilted leaves showed relatively higher CWD infection and
could be considered as susceptible to the disease.
Table 2: The analysis of variance (ANOVA) of CWD and seedling growth characters mean squares for 17 Arabica
coffee genotypes
Characters mean square and p’
Sources
DF WS
(%)
IP
(days)
AUDPC NDL
(no.)
NYL
(no.)
SH
(cm)
SSD
(cm)
AINL
(cm)
NN
(no.)
PL
(cm)
LA
(cm2)
NL
(no.)
Block 2
1000.98
(666.29)
456.37
5110325.
2
0.010 0.040 0.89 0.024 0.42 0.036 0.002 1.056 0.544
Genotyp
es
16
2161.31**
(1179.73**)
1290.27
**
16205358
.7**
0.241
**
0.255
**
6.31**
0.039*
*
1.83**
0.267*
*
0.005*
*
9.49**
0.766*
*
Error 32 103.11 (58.35) 157.77 784550.8 0.029 0.050 0.400 0.005 0.101 0.011 0.0005 0.967 0.125
*, ** = significant at 5% and 1% probability level, respectively, DF = degree of freedom, p’ = probability level, cm= cent
meter, cm2= cent meter square, mm= mill meter, no. = number AINL= average inter node length, AUDPC = area under
disease progress curve, IP = incubation period, LA= leaf area, NDL= number of defoliate leaves per seedling, NL= number
of leaves per seedling, NN= nodes number, NYL= number of yellow leaves per seedling, PL= petiole length, SH= seedling
height, SSD= seedling stem diameter, WS%= Wilted coffee seedlings percentage. Data in bracket is arcsine transformed
value of wilted seedlings percentage
In general, the mean analysis result of genotype 279/71
was the lowest wilted seedling percentage, minimum
number of defoliate leaves and yellow leaves per seedling,
longest incubation period, tallest height and widest leaf
area compared to others. Therefore, it was promising
genotype to CWD resistant and for most other important
characters; followed by 974 and 79233. However,
genotypes 279/71 and 971 were not significantly different
for wilted seedling percentage. On the other hand, Catimor
J-21 was susceptible to CWD and undesirable genotype
for the characters mentioned above, followed by Catimor
J-19, Geisha, 75227 and B-64/04. Therefore, the present
study confirmed that 279/71, 971, 974 and 79233
genotypes revealed resistant to moderately resistant or
tolerant to CWD and important to inclusion in future
resistance breeding programs. Compared with inoculated
seedlings non inoculated ones showed no any CWD
symptoms or death on the same experimental pots.
CWD resistant genotypes showed relatively and
significantly longer incubation period, elongated height,
wider leaf area and stem diameter than the susceptible
genotypes. This result contributes to some insight for CWD
resistant selection criteria. The incubation period result
indicated that after the pathogen favor for penetration to
the genotypes, the host (Arabica coffee genotype) struggle
to protect themselves from a severe infection, even after
the infection takes place. The host most likely defends
themselves through either genetic, mechanical barrier or
chemical release or a combination of these defense
mechanisms before symptoms appearance on their parts.
This statement also supported by Agrios (2005), some of
the plant defense structures and substances exist before
the plant comes into contact with the pathogen, but the
most effective defense structures and substances are
produced in response to attack by the pathogen. Similarly,
wide stem diameter and leaf area possibly important for
resistance. Because, the wider diameter can provide some
amount of water from the root to the upper parts of the
seedling and withstand translocation problems, even if
there are clogging and hindrances of pathogens parts
inside it. So, the seedlings accomplish their physiological
activities and survive better than the thin diameter
genotypes. In case of extensive leaf area also survive
more due to the ability to photosynthesis efficiently and
prepare their optimum food. As a result, stem diameter
together with leaf area benefit the seedlings to become
better survive since the relatively optimum amount of water
translocation through the stem to the leaves parts to make
photosynthesis and synthesized food move into stem and
root to perform its physiological activities.
The present result is in harmony with some previous
scholars. According to Chala et al. (2012) varieties 971
and 974 showed low wilted seedling percentage and
considered as CWD resistant genotypes. Demelash
(2013) also reported 279/71 and 370 as CWD resistant
genotype; but the current result showed that 370
genotypes infected about 58%, it is a contradictory result.
Through continuous observation and follow up in the

5. Evaluation of Promising Coffee Wilt Disease (Gibberella xylarioides) Resistant Arabica Coffee (Coffea arabica L.) Genotypes in Ethiopia
Int. J. Plant Breed. Crop Sci. 889
germplasm conservation field, genotype 79233 did not
manifest any tree death; even though all coffee genotypes
were dead around it due to Gibberella xylarioides. Then,
this genotype was included in the study to check their
resistant level in the artificial inoculation test. Despite this,
some number of wilted seedlings happened; it gave
consistent resistant reaction and ranked the 4th resistant
genotype compared to all tested or previously screened
CWD resistant genotypes. However, the current results
for Catimor J-21 and Catimor J-19 varieties were different
from Girma (2004) report; he considered that these
varieties showed CWD resistant reaction under seedling
inoculation test and used as a resistant check in most
CWD screening studies. The possible cause of the present
result disagreement with previous works can be the type
of isolate used, differences between technical experts to
wound seedlings and put proper inoculum concentration
on it, environmental (greenhouse) conditions and season
or the combination of these factors during inoculation.
Figure 1: Arabica coffee variability for CWD and growth characters using artificial inoculation test in the
greenhouse;
A) resistant genotype (279/71) B) susceptible genotypes (Geisha) C) variability of genotypes to CWD at similar condition

6. Evaluation of Promising Coffee Wilt Disease (Gibberella xylarioides) Resistant Arabica Coffee (Coffea arabica L.) Genotypes in Ethiopia
Admikew Y. 890
Table 3: Mean performance of 17 Arabica coffee genotypes for CWD and seedling growth characters
Genotypes WS (%) IP (days)
AUDP
C
NDL NYL SH (cm) SSD (cm) AINL (cm) NN PL (cm) LA (cm2) NL
75227 67.8 (56.0) 91.7 5042.5 0.20 0.60 11.2 2.10 3.99 1.81 0.47 10.7 5.31
971 8.6 (13.0) 121.0 275.1 0.49 0.53 12.3 2.20 2.80 1.96 0.50 11.2 5.82
74110 66.7 (54.8) 104.7 3080.0 1.00 0.42 10.3 2.03 2.42 2.31 0.45 8.4 6.49
8136 57.8 (49.6) 106.7 3289.4 0.27 0.24 11.4 2.09 2.97 1.91 0.46 10.1 5.60
79233 35.0 (36.2) 125.3 1061.7 0.18 0.11 10.8 2.06 2.32 2.16 0.35 7.1 6.18
74144A 45.6 (42.5) 98.7 3013.7 0.68 0.32 11.4 2.15 2.86 2.26 0.46 9.0 6.34
974 23.3 (27.8) 121.0 653.3 0.09 0.11 11.9 2.11 3.75 1.20 0.43 9.9 4.80
370 58.5 (50.2) 116.7 2991.6 0.14 0.16 12.2 1.98 4.25 1.33 0.48 11.8 4.98
Catimor J-
19 93.3 (81.1) 73.7 6517.2 0.47 0.63 8.1 1.84 1.48 2.05 0.39 6.4 6.04
Catimor J-
21 94.7 (82.2) 71.0 8114.5 0.52 1.20 7.9 1.92 1.59 2.03 0.38 6.7 6.01
7440 65.0 (54.4) 98.0 4328.3 0.89 0.18 11.9 2.27 2.98 2.13 0.48 11.4 5.95
279/71 6.8 (12.5) 155.0 192.8 0.00 0.02 12.3 2.18 3.39 2.00 0.43 11.9 6.00
B-64/04 79.6 (63.8) 104.7 4172.4 0.51 0.27 10.5 1.96 2.94 1.77 0.44 8.3 5.35
B-70/04 57.6 (49.4) 94.7 3110.1 0.15 0.29 10.1 2.08 3.04 1.94 0.44 10.2 5.38
74144B 66.7 (54.8) 99.3 3383.3 0.49 0.49 12.3 2.11 2.87 2.16 0.46 9.7 6.12
Geisha 89.5 (71.1) 78.0 7113.4 0.38 0.63 8.6 1.90 2.05 2.08 0.44 9.3 6.00
SN-5 41.1 (39.8) 112.3 1678.2 0.15 0.13 10.9 2.10 3.73 1.72 0.44 11.7 5.02
Mean 56.33(49.4) 104.26 3412.8 0.39 0.37 10.83 2.06 2.91 1.93 0.44 9.62 5.73
LSD (0.05) 16.89(12.7) 20.89 1473.1 0.28 0.37 1.05 0.11 0.53 0.18 0.04 1.64 0.59
CV (%)
18.02(15.46
) 12.05 25.95 43.06 59.29 5.86 3.31 10.92 5.55 5.26 10.22 6.16
Data in bracket is arcsine transformed value of wilted seedlings percentage, cm= cent meter, cm2= cent meter square,
mm= mill meter
AINL= average inter node length, IP = incubation period, LA= leaf area, NDL= number of defoliate leaves per seedling,
NL= number of leaves, NN= number of nodes, NYL= number of yellow leaves per seedling, PL= petiole length, SH=
seedling height, SSD= seedling stem diameter, TWS%= Transformed value of Wilted seedlings percentage, WS%= Wilted
coffee seedlings percentage

7. Evaluation of Promising Coffee Wilt Disease (Gibberella xylarioides) Resistant Arabica Coffee (Coffea arabica L.) Genotypes in Ethiopia
Int. J. Plant Breed. Crop Sci. 891
Figure 2: AUDPC on CWD severity in Arabica coffee genotypes
Heritability
According to Verma and Agarwal (1982), heritability values
greater than 50% are considered as high, values less than
20% are low and between 20 to 50% as medium. Based
on this, all characters resistance showed high broad sense
heritability. The manifested of high broad sense heritability
along with GAM showed for low wilted seedling
percentage (CWD resistance), incubation period, seedling
height, average inter node length, nodes number, leaf
area, minimum number of defoliate leaves and yellow
leaves. According to Allard (1999) and Acquaah (2012)
heritability explanation, for these characters the observed
variability mostly due to heredity (genetic). Based on Table
4, the genotypic variance is greater than the environmental
variance for all traits. It indicates that the characters are
controlled most importantly by genes even if
environmental factors have their contribution. Therefore,
the phenotypic value of the characters used as a guide to
the breeding value (additive effect) and it aid to make
selection easily. As Fehr (1987) described, the
effectiveness of selection for a trait depends on the relative
importance of genetic and non-genetic factors in the
expression of phenotypic differences among genotypes in
a population.
Table 4: Estimation of variance components, heritability and GAM for CWD parameters and seedling growth
characters
Characters 𝛅 𝟐
p 𝛅 𝟐
g 𝛅 𝟐
e H2B GA GAM
LWSP 720.44 686.07 34.37 95.23 52.65 93.48
Incubation period 430.09 377.50 52.59 87.77 37.50 35.97
MNDL 0.080 0.071 0.010 87.97 0.51 131.70
MNYL 0.085 0.068 0.017 80.39 0.48 130.49
Seedling height 2.102 1.97 0.133 93.66 2.80 25.83
Stem diameter 0.013 0.011 0.002 87.18 0.20 9.94
Average inter node length 0.610 0.576 0.034 94.48 1.52 52.24
Nodes number 0.089 0.085 0.004 95.88 0.59 30.53
Petiole length 0.0017 0.0015 0.0002 90.00 0.08 17.20
Leaf area 3.163 2.841 0.322 89.81 3.29 34.21
Leaves number 0.255 0.214 0.042 83.68 0.87 15.20
H2B= broad sense heritability, GA =genetic advance (5% of selection), GAM =genetic advance as percent of mean, 𝜹 𝟐
g=
genetic variance, 𝜹 𝟐
p =phenotypic variance, LWSP =low wilted seedling percentage, MNDL = minimum number of
defoliate leaves, MNYL = minimum number of yellow leaves

8. Evaluation of Promising Coffee Wilt Disease (Gibberella xylarioides) Resistant Arabica Coffee (Coffea arabica L.) Genotypes in Ethiopia
Admikew Y. 892
CONCLUSION
Coffee wilt disease is a vascular disease caused by
Gibberella xylarioides Heim and Saccas. It becomes an
increasing importance in Arabica coffee production.
Testing of different Arabica coffee genotypes provide
valuable evidence in the development of CWD resistant
variety (ies). The trail was conducted to identify promising
resistant genotypes, to estimate heritability and genetic
advance of CWD and growth traits..
Among the genotypes under the test 279/71 (6.84%)
exhibited the lowest wilted seedling percentage, minimum
number of defoliated leaves and yellow leaves per
seedling, extended incubation period, tall in height and
wide leaf area. So, it was considered as a promising
genotype to CWD resistance followed by 971 (8.60%), 974
(23.33%) and 79233 (35.00%).These genotypes are
important for inclusion in future resistance breeding
programs. Furthermore, the estimation of high broad
sense heritability coupled with GAM were observed for
wilted seedling percentage, incubation period, average
inter node length, leaf area and number of defoliated
leaves per seedling; it could be improved easily through
selection.
It can be concluded that promising CWD resistant
genotypes were identified which should be evaluated
further for CWD, other major diseases, yield and important
agronomic traits at multi-locations under open field
conditions.
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Accepted 5 October 2020
Citation: Admikew Y (2020). Evaluation of Promising
Coffee Wilt Disease (Gibberella xylarioides) Resistant
Arabica Coffee (Coffea arabica L.) Genotypes in Ethiopia.
International Journal of Plant Breeding and Crop Science,
7(3): 885-893.
Copyright: © 2020: Admikew Y. This is an open-access
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