DGG/MNG REPUBLIC OF SENEGAL ----------- ...
DGG/MNG
REPUBLIC OF SENEGAL
-----------
MINISTRY OF RURAL DEVELOPMENT
DEPARTMENT OF RESEARCH
-----------
ON CROP PRODUCTION
SENEGALESE INSTITUTE OF
---------------_--
------------------
AGRICULTURAL RESEARCH
-----------
SYNTHESIS OF THE
ACTIVITIES ON COWPEA ',
1987
BY
D.G. GAIKW
MARCH .t988
NATIONAL CENTRE OF
AGRONOMICAL RESEARCH, BAMBM
-l-
Resistance screening was
e main research activity during 1987.
A disease nursery initiated in 1986 or multiple disease resistance screening
was continued during 1987.
screening for virus resistance in the
field as well as in the screen house and the bacterial blight screening in
the screen house was also continued. In addition, some work on transmission
c.f virus through seed and by insects was initiated. Experiments on estimation
of losses in yield due to virus and acterial blight were also initiated.
In the laboratory studies,
re made to examine the pathogens associated
with cowpea seed and seedli
d their control through use of various
seed dressers. High li,ghts
ults of a11 these experiments are summarised
in the following paragraphs.
1. Resistanc
9 F2 families during
(March - May 87).
revealed that 32
of them were susceeptible while the
maining 101 lines were observed to be free
from virus infection.
eened in the screen
house by artificial inoculation,
susceptible while 65
were resistant. 49 lines were observe
to be resistant both in the field as ltiell
as screen house test.
above material together
iny season. Out of 42,
nts ; Mougne, Casa 16,
, Casa 3 and 59-9 were
susceptible. Reactions of Mougne,
were contradictory to
Casa 16 and CB5 were
ries from the cross
B 21 x Tvx
81 D 1137 and 4 parents
when screened in the field at Djibelo
revealed that a11 the entries from the
cross B21 x Tvx 3236 and 2 entries
IS 86 299N and IS 86 253.N from the cross
, 58-57 x IT 81 Dl137 were resistant.
3 were free viz. B21,
s together with 4 check
mber-october 87 under
artificial inoculation.
f 38 breeding lines,
28 were resistant. Amongst the check
arieties 58-57 was susceptible while B21,
Mougne and Tvx 3236 werle. resistant.
1.2. Mul,tiple disease s/creening nursery :
I
Out of 243 entries
37 were free from web blight infection
while 79 were resistant to ashy stem
ight. There was heavy disease pressure
of both web blight and ashy stem bligh
in the disease nursery resulting in poor
development of other diseases such as irus, bacterial blight, Cercosporiose etc.
-7-
Only 6 entries showed virus infection while 17 entries exhibited bacterial blight
infection. Infection of Cercospora le f spot appeared late and was developed on
34 entries. Choanephora pod rot was a so comparatively poor
and was seen on 31 entrie
only. The following 14 varieties which had
enough plant stand (more than 10) wer observed to be free from a11 the diseases.
78-21, 78-29, 66-73, 78-46, 78-6, Tvx 3236, 79-19, 63-5, 78-5, 78-10, 58-95 W,
66-76, 78-3 and 60-40.
1.3. Screenin
ines and 4 parents were
ults indicated
that out of 51 breeding lines,
erial blight infection,
3 showed resistant reaction,
2 moderately suceptible,
ogenous reaction. Amongst
the varieties,
8-57 and Tvx 3236 remained
free+ .
showed that plots so‘wn with
seeds collected from the virus infecte
plants had 10 to 22% virus incidence with
on through seed is quite
high and emphasizes the need of healt
seed production.
rotection of plants from
insects using insecticide (thimul 35
2) no protection was
of aphids was noticed at
At Djibelor cowpea beetles
were observed which serve as vector fo southern bean mosaîc virus. At Bambey the
rotected plots. It was
hich was taken after 52
the aphids were respon-
plants. Similar trend
In the first observation there was very
neglegible virus incidence while in th second observation the virus incidence was
nsmitting the virus.
III. Assessmer
imate the losses in
1) Minimum disease infection
ion by use of infected seed
the average disease
tion in the yield in the
inoculated plots.The inoculated plots ave average yield of 440 Kg/ha while it was
7113 Kg/ha in the uninoculated plots.
% (273 Kg/ha) yield loss
3.2. Due to virus :
Similar tria1 was conduct d at Bambey and Djibelor toassess yield losses
due to vi% on 58-57. There were 2 treatments viz., 1) Minimum disease infection
through use of healthy seed and con rol of vect= and 2) Maximum disease infection
through use of infected seed and ar ificial inoculation of plants. The results
obtained at Bambey showed 10% avera e virus incidence in the uninoculated plots
and 38.75% in the inoculated plots. The average yield figures were 603 Kg/ha and
498 Kgjna respectiveliy for uninocul ted and inoculated plots indicating there by
17.41% (105 kg/ha) yield loss due t more virus incidence in the inoculated plots.
Very low yields were obtained at Dj bélor. However, the trend was the same.
IV. Identification of see microflora and their control :
,
Attempts were ma
the pathogens attacking seed which resulteti
in seed rot/root rot and t
Seeds of 3 varieties 2, B21, 58-57 and
Mougne were treated with G
Benomyl (lg/Kg) and Thiram (2g/Kg). One
set of untreatedseed serve
eed microflora was detected by rolled
towel method. The results
B21 was more prone to infection of fungi
causing seed root/root rot
In B21, seed dressing with Granox
and Benomyl reduced these diseases
ely than Thiram. In case o.f 58-57
a11 the fungicidesshowed e
due to the fact that this variety
seed was less infected while in cas of Mougne Granox was most effective with no
seed or root rot followed
The following microflora was detected in the
seed and root rots of thes
eyuiseti, Fusarium -p, Yenicillium sa,
capsici t Curhalaria g,, ISper~illua ~3.~
I,
V. Survey of cowpea disea
During 1987 season diseas
problems"were comparatively more than previous
year. Incidence of ashy stem blight nd web bligh w s very serious and was seen at
almost a11 the locations and trials.iOn farmers' &%%$% ese two were the main disease
encountered. Incidence of bacterial light and virus was asusual
on B 21 and 58-57
respectively..Bacterial blight was qu te high on B 21 at Nioro.
Choanephora pod rot was mi or. SO also the cercosporiose which was mostlh
noticed on midlate and late varietie
at the end of trop cycle.Striga incidence was
increased at Ndatt 'FalXKebemer Depa tement).
.
/
VI. Seed Production :
/
During 1987 season seed mu tiplication plots of B 21 and CB 5 were observe{
to be,infected by Rhizoctoniose whil 58-57 plot showed some virus infected plants.
Roguing of infected plants was exerc sed to obtain disease free seed.'
VII Summarv :
Out of 133 lines grown at
during off season (March-May 87:), 101. wer
observed to be free from virus.
, when these lines were screened in the scree
house under artificial
49 lines were found to be resistant.
REPUBLIC OF SENEGAL
-----------
MINISTRY OF RURAL DEVELOPMENT
DEPARTMENT OF RESEARCH
-----------
ON CROP PRODUCTION
SENEGALESE INSTITUTE OF
---------------_--
------------------
AGRICULTURAL RESEARCH
-----------
SYNTHESIS OF THE
ACTIVITIES ON COWPEA ',
1987
BY
D.G. GAIKW
MARCH .t988
NATIONAL CENTRE OF
AGRONOMICAL RESEARCH, BAMBM
-l-
Resistance screening was
e main research activity during 1987.
A disease nursery initiated in 1986 or multiple disease resistance screening
was continued during 1987.
screening for virus resistance in the
field as well as in the screen house and the bacterial blight screening in
the screen house was also continued. In addition, some work on transmission
c.f virus through seed and by insects was initiated. Experiments on estimation
of losses in yield due to virus and acterial blight were also initiated.
In the laboratory studies,
re made to examine the pathogens associated
with cowpea seed and seedli
d their control through use of various
seed dressers. High li,ghts
ults of a11 these experiments are summarised
in the following paragraphs.
1. Resistanc
9 F2 families during
(March - May 87).
revealed that 32
of them were susceeptible while the
maining 101 lines were observed to be free
from virus infection.
eened in the screen
house by artificial inoculation,
susceptible while 65
were resistant. 49 lines were observe
to be resistant both in the field as ltiell
as screen house test.
above material together
iny season. Out of 42,
nts ; Mougne, Casa 16,
, Casa 3 and 59-9 were
susceptible. Reactions of Mougne,
were contradictory to
Casa 16 and CB5 were
ries from the cross
B 21 x Tvx
81 D 1137 and 4 parents
when screened in the field at Djibelo
revealed that a11 the entries from the
cross B21 x Tvx 3236 and 2 entries
IS 86 299N and IS 86 253.N from the cross
, 58-57 x IT 81 Dl137 were resistant.
3 were free viz. B21,
s together with 4 check
mber-october 87 under
artificial inoculation.
f 38 breeding lines,
28 were resistant. Amongst the check
arieties 58-57 was susceptible while B21,
Mougne and Tvx 3236 werle. resistant.
1.2. Mul,tiple disease s/creening nursery :
I
Out of 243 entries
37 were free from web blight infection
while 79 were resistant to ashy stem
ight. There was heavy disease pressure
of both web blight and ashy stem bligh
in the disease nursery resulting in poor
development of other diseases such as irus, bacterial blight, Cercosporiose etc.
-7-
Only 6 entries showed virus infection while 17 entries exhibited bacterial blight
infection. Infection of Cercospora le f spot appeared late and was developed on
34 entries. Choanephora pod rot was a so comparatively poor
and was seen on 31 entrie
only. The following 14 varieties which had
enough plant stand (more than 10) wer observed to be free from a11 the diseases.
78-21, 78-29, 66-73, 78-46, 78-6, Tvx 3236, 79-19, 63-5, 78-5, 78-10, 58-95 W,
66-76, 78-3 and 60-40.
1.3. Screenin
ines and 4 parents were
ults indicated
that out of 51 breeding lines,
erial blight infection,
3 showed resistant reaction,
2 moderately suceptible,
ogenous reaction. Amongst
the varieties,
8-57 and Tvx 3236 remained
free+ .
showed that plots so‘wn with
seeds collected from the virus infecte
plants had 10 to 22% virus incidence with
on through seed is quite
high and emphasizes the need of healt
seed production.
rotection of plants from
insects using insecticide (thimul 35
2) no protection was
of aphids was noticed at
At Djibelor cowpea beetles
were observed which serve as vector fo southern bean mosaîc virus. At Bambey the
rotected plots. It was
hich was taken after 52
the aphids were respon-
plants. Similar trend
In the first observation there was very
neglegible virus incidence while in th second observation the virus incidence was
nsmitting the virus.
III. Assessmer
imate the losses in
1) Minimum disease infection
ion by use of infected seed
the average disease
tion in the yield in the
inoculated plots.The inoculated plots ave average yield of 440 Kg/ha while it was
7113 Kg/ha in the uninoculated plots.
% (273 Kg/ha) yield loss
3.2. Due to virus :
Similar tria1 was conduct d at Bambey and Djibelor toassess yield losses
due to vi% on 58-57. There were 2 treatments viz., 1) Minimum disease infection
through use of healthy seed and con rol of vect= and 2) Maximum disease infection
through use of infected seed and ar ificial inoculation of plants. The results
obtained at Bambey showed 10% avera e virus incidence in the uninoculated plots
and 38.75% in the inoculated plots. The average yield figures were 603 Kg/ha and
498 Kgjna respectiveliy for uninocul ted and inoculated plots indicating there by
17.41% (105 kg/ha) yield loss due t more virus incidence in the inoculated plots.
Very low yields were obtained at Dj bélor. However, the trend was the same.
IV. Identification of see microflora and their control :
,
Attempts were ma
the pathogens attacking seed which resulteti
in seed rot/root rot and t
Seeds of 3 varieties 2, B21, 58-57 and
Mougne were treated with G
Benomyl (lg/Kg) and Thiram (2g/Kg). One
set of untreatedseed serve
eed microflora was detected by rolled
towel method. The results
B21 was more prone to infection of fungi
causing seed root/root rot
In B21, seed dressing with Granox
and Benomyl reduced these diseases
ely than Thiram. In case o.f 58-57
a11 the fungicidesshowed e
due to the fact that this variety
seed was less infected while in cas of Mougne Granox was most effective with no
seed or root rot followed
The following microflora was detected in the
seed and root rots of thes
eyuiseti, Fusarium -p, Yenicillium sa,
capsici t Curhalaria g,, ISper~illua ~3.~
I,
V. Survey of cowpea disea
During 1987 season diseas
problems"were comparatively more than previous
year. Incidence of ashy stem blight nd web bligh w s very serious and was seen at
almost a11 the locations and trials.iOn farmers' &%%$% ese two were the main disease
encountered. Incidence of bacterial light and virus was asusual
on B 21 and 58-57
respectively..Bacterial blight was qu te high on B 21 at Nioro.
Choanephora pod rot was mi or. SO also the cercosporiose which was mostlh
noticed on midlate and late varietie
at the end of trop cycle.Striga incidence was
increased at Ndatt 'FalXKebemer Depa tement).
.
/
VI. Seed Production :
/
During 1987 season seed mu tiplication plots of B 21 and CB 5 were observe{
to be,infected by Rhizoctoniose whil 58-57 plot showed some virus infected plants.
Roguing of infected plants was exerc sed to obtain disease free seed.'
VII Summarv :
Out of 133 lines grown at
during off season (March-May 87:), 101. wer
observed to be free from virus.
, when these lines were screened in the scree
house under artificial
49 lines were found to be resistant.