REPUBL1.C OF SENEGAL .4 ___------. MINISTRY ...
REPUBL1.C
OF SENEGAL
.4
___------.
MINISTRY OF RURAL DEVELCIPMENT
1 ,' -'.' :*
DEPAKTMENT OF RESEARCH
_-m-w----
ON CROP PRODUCTION
SENEGALESE .~NSTITU'I'E
-w--m -e---e-
131: .ACRl.CULTURAL RESEARCH
__-_----
ANNUAL REPORT
ON COWPEA
PATHOLOCX - 1987
BY
D.G. (;AIKWAD
-:
NATIONAL CENTRE OF AGRONOMIC
REBEARCI-1 - BAMBM
A disease nursery initiated during 1986 for multiple disease
resistance screening was continued during this year also. There was hea-
vy natural infection of ashy stem blight and web blight in the disease
nursery. This opportunity was taken to score the test entries against
Lhese diseases.Screening
for virus resistance in the field at Djibelor as
well as at Bambey and in the screen house was also continued. Some work
on transmission studies of virus through seed and by insects was initiated.
Similarly experiments for estimation of yield losses due to
virus and bacterial blight diseases were conducted. In the laboratory stu-
dies, attempts were made to examine the pathogens associated with cowpea
seed and seedling rots and their contrôl through use of various seed
dressers. The results of a11 these experiments are discussed in the fol-
l o w i n g p a g e s .
1. Resistance Screening for major diseases.
-
1.1. Screening for virus resistance.
133 individuai plant selections made from 9 F2 families during
1986 rainy season a.t Djibelor were grown at Bambey during off season( Nai?ch-
May ),Natural virus infection was observed on some,. of the lines..Cbserva-
tions of virus incidence on these entries are presented in tablti 1. The
available entries were also screened in the screen house by artificial
inoculation,O-5
seeds of each entry were sown on 2.3.87 in separate pot,
The inoculation was done twice, first on 11.3.87 and the second on 13.3.87.
The inoculum was prepared by blending the infec-ted leaves collected
from
58-57 plot at Bambey during off season in a buffer solution of sodium and
potassium phosphates. Carborundum powder was dusted on the leaves before
inoculation to act as an abrasive. The inoculation was done by rubbing
the primary leaves with a forefinger wetted with the inoculum.
The virus symptoms started appearing in the second week after
inoculation. Final observations were recorded one month after inoculation
and are given in table 1.
Table 1 : Results of virus screening in the field and screen house during
off season.
%
Cross and Entry No
Incidence in
Screen house
the field
Reaction
Casa 16 x B 2;.
1
23 .O8
S
2
14.29
S
3
0.00
N A
4
0.00
NA
5
0.00
NA
6
0.00
R
7
33.33
S
8
0.00
R
9
0.00
NA
10
17.65
S
11
15.35
R
12
20.00
R
13
66.67
NA
14
50.00
S
15
0.00
S
16
36.36
S
17
50.00
NA
18
0.00
NA
19
0.00
N A
59-9 x 321
20
0.00
R
2 1
0.00
NA
2 2
0.00
N A
23
0.00
NA
24
0.00
R
59-q x 0 21
25
0.00
NA
26
0.00
R
27
0.00
NA
28
0.00
NA
29
0.00
R
30
0.00
N A
3
%
Cross and Entry No
Incidence in
Screenhouse
the field
Reaction
I NA
Casa 3 x B21
32
0.00
1 R
33
6.25
I
S
3 4
0.00
I
NA
35
0.00
l
S
36
0.00
I
S
37
0.00
I
R
3 8
0.00
I
R
3 9
0.00
I
NA
40
0.00
I
NA
41 1 0.00
I
R
42 1 0.00
I
NA
43 1 0.00
I
NA
44 1 0.00
I
NA
45 1 0.00
I
R
46 1 0.00
I
R
47 1 0.00
I
S
48 1 0.00
I
R
49 1 0.00
I
NA
50 1 0.00
I
NA
Casa 3 x B21
51 1 0.00
I
S
52 1 0.00
I
R
53 I 0.00
I
NA
54 1 0.00
I
R
55 I 0.00
I
R
56 1 0.00
I
R
57 I 0.00
I
NA
58 1 0.00
I
R
59 I 0.00
I
NA
60 1 0.00
I
R
61 1 0.00
I
NA
62 1 0.00
I NA
63 1 0.00
I
NA
64 1 0.00
I NA
4
%
Cross and Entry No
Incidence
Screenhouse
in the ffield
Reaction
Casa 16 (B 2 1 x 1137)
65
15.56
I
R
66
1 6.67
l
R
67
(38.46
I
S
68
I 0.00
I
R
69
I 0.00
l
R
70
1 4.76
I
S
71
I 0.00
I
S
72 I 0.00
l
R
73
1 0.00
l
S
74
I 0.00
I
S
75 I 0.00
I
R
Mougne (Mougne x 1032)
76 I 0.00
I
R
77 1
6.25
I
R
78 133.33
I
S
79
1 26.67
I
R
80
1 5.88
I
R
81
Ill.76
I
R
82
I 0.00
I
NA
83
I 11.11
I
NA
84
1 0.00
I
S
85
I 0.00
I
R
86
1 5.56
I
R
87
l 0.00
I
S
88
I 0.00
I
NA
89
I 0.00
I
NA
90
I 0.00
I
R
9l
I 0.00
I
R
92
0.00
I
R
93
0.00
I
R
VLP Casa 16 x B 21
94
1 6.67
I
R
95
114.29
I
R
96
123.08
I
R
97
I 0.00
I
NA
98
I 0.00
I
R
99
I 0.00
I
NA
100
I 0.00
I
R
5
%
Cross and Entry N'
Incidence in
Screenhouse
the fiel-d
Qeaction
VLtJ L'asa In x IS'l
L
lU1
.
I
3
102
133.33
I
S
103
I 0.00
I
R
104
~80.00
I
S
105
I 0.00
I
R
106
I 10.00
I
S
107
133.33
I
R
58-57 x TVU 1185
10%
I 0.00
I
R
109.
I 0.00
1 R
110
I 0.00
I
R
111
I 0.00
I
R
112
I 0.00
I
R
Casa 16 x CB5
113
I 0.00
I
S
114
10.00
I
R
115
I 0.00
I
R
116
l 0.00
I
R
ll7
I 0.00
I
NA
1 1 %
I 0.00
I
R
119
I 0.00
I
R
120
I 0.00
1 R
121
l 0.00
l
S
122
I 0.00
I
R
123
I 0.00
I
S
124
I 0.00
I
S
125
I 0.00
l
S
126
I 0.00
I
R
127
I 0.00
I
NA
Mougne x TVU 11.85
12%
1 0.00
I
R
129
I 8.33
l
R
130
110.53
I
R
131
1
6.25;
I
R
132
I 0.00
i
R
133
I 0.00
I
R
Notes :
R, Résistant
S, Susceptible
NA- R&act:ion not available
In the field observations 101 entries were observed to be free
from virus infection. Al1 the entries of the crosses 59-9 x B21(12),
.58-57 x TW 1185 (5) and C;asa 16 x CB5 (15) did not show virus infection.
However , the screen house reactions were partially confirming the field
observations. In the screen house test 65 entries showed resistant reac-
tion and 29 susceptible. In this test also no entry from the crosses
59-9 x B21 and 58-57 x ~~‘~1185 showed susceptible reaction. During 1986
screening at Dj ibelor , a11 the plants of the family 59-9 x B21 were also
observed to be free from virus. In a11 49 entries showed resistant reac-
tion in the screen house test as well as no virus incidence in the field.
From the material planted in the field, individual plant selections were
made based on virus resistance and other desirable characters.
An experiment with 42 individual plant selections made from
the above mentioned off season experiment together with 8 parents was laid
out during rainy season of 1987 at Djibelor for confirming the virus
resistance of these selections. The screening method
was the same that was used during 1986 season. One line of a local suscep-
tible variety (Spreader row) was planted after every two test entries for
multiplying the inoculum. The spreader rows were sown on 15.07.1987. The
test entries were sown on ll.and 12.08.87. By ‘this time the virus had
started appearing on the spreader rows. The test entries were inoculated
on 26.08.87 and 27.08.87 with the sap from the infected leaves,@arborundum
powder was added to the inoculum to act as an abrasive. The inoculation
was done by rubbing the fully grown well expanded primary leaves with a
forefinger wetted with the inoculum.
The virus symptoms on the test entries had started appearing
in the first week (of september. However,at the time of first observation
which was taken on 8.09.87 the incidence was almost neglegible. The second
observation was recorded on 25.09.87 which revealed 5 entries .L:ving
virus infection while the rest were still free of virus. In the final
observations which were recorded on 23.10.87, 13 entries showed virus in-
fection. The results of the final observations are summarised in table 2.
Table 2 : Virus incidence in the field at Djibelor
on selected material of F4 generation.
.
--
-
Cross & Entry na
Virus
Other
Virus
Other
incidence %
Diseases
Cross & Entry
incidence %
diseases
(AV of2 rep)
noticed
No
(AV of 2 rep)
noticed
--.
Dlougne x (MougnexIT 810 1032)
Casa 3 x B 21
4-2
5.88
26
3
0.00
l-l
3.85
27
15 -1
0.00
l-4
0.00 -
WB
2 8
15 -1
0.00
WB
2-1
0.00
2 9
2 0
0.00
WB
2-3
0.00
30
23
0.00
WB
3-l
10.72
31
29 -1
0.00
3-3
0.00
32
29 -1
0.00
5-2
2.94
3 3
3 3
0.00
59.9 x B21
6-l
0.00
34
6
0.00
58-57 x TW 1185
8-2
0.00
WB
3 5
1 y1
0.00
13-2
0.00
WB
36
1 -1
0.00
13-4
0.00
WB
37
4 -1
5.00
WB
:14-1
0.00
38
4 -1
4.55
WB
15-6
5.88
3 9
4 -1
1.00
18-6
0.00
4 0
4 -1
0.00
Casa 16 x CB5
1 6
12-l
4.76
41
5-l
0.00
17
12-2
o.oc
WB
42
?Y2
2.63
Parents
7-l
0.00
43
Mougne
0.00
7-2
0.00
4 4
58 -57
5.88
8
0.00
4 5
m -81~1032 0.00
14
0.00
NB
4 6
Casa 16
0.00
WB
Casa 16 x B21
?2
6
0.00
4 7
CB 5
0.00
0’3
-.
10
0.00
48
TV’JJI 185
o,oo
Casa 16 X(B21x1137)
24
1
0.00
49
Casa 3
6.25
25
2
0.00
50
59-9
26.72
Yot e : WB = WEB BLIGHT
8
From the results in table 2 it is seen that 5 parents viz ;
Mougne, Casa 16, CB5, IT 81D 1032 and TWJ 1185 are resistant while 58-57,
Casa 3 and 59-9 are susceptible. Reactions of Casa 16 and 59-9 were con-
tradictory to the reactions obtained last year. In the screen house test
conducted during Xov.86GJan.87 Casa 16 showed susceptible reaction while
59-9 was free of virus. Mougne and CB5 which are free of virus in this -tes.; were
obser;rnd .tc, be susceptible on farmers’ fields during last year.
Another set of 38 entries were also screened alongwith the ex-
neriment described on the previous page. This set consisted of 30 entries
from the cross B 21 x TVX3236,4 entries from the cross 58-57 x IT 81D1137
(which were found resistant during 1986 screenirg)and
4 parents. The
screeningmethod was the same that was followed for the previous experiment..
The sowing was done on 11.08.87 and the inoculation on 26.08.87. At the
time of first observation on 8.09.87 ; 2 entries
and 1 parent (58-57)
showed virus infection. The subsequent observations were noted on 25.09.87
and 23.10.87. The results of the final observations are presented in
table 3.
9
Table 3 : Virus incidence in the field at Djibelor on advance generation
-
-
e
-
m
-
. -
material..-
Cross & Entry No
IViruslOther 1 Cross & Entry No
IVirus 1 Other
Inci- Diseg-
I
I
I
Inci-
I
I Diseases
dence ses No-
dence$ Noticed
l%(~v.iticed 1
I (AV of I
of 21
2 Rep)
.Rep )
-
-
,-
B21 x TVX. 3236
B21 x TJX. 3236
1
’
ISB6
60~
0.00 WB,ASB 24
Ts86
84~
0.00
a.
..: CI
:.(l
2
1s,B6
62~
0.. 00
25
1.~86 85N
0.00
3
IS86
63N
0.00 WB
26
1$'84
86~
0.00
4
IS36
64~
0.00
27
1s 86 87N
0.00
5
1s 86
65N
0.00.
2 8
Is86
88~
0.00
WB
6
IS 36
66~
0.00
29
1s 86 89N
0.00
7
IS86
67N
0.00
3 0
Is86
9ON
0.00
8
IS 36
68~
0.00 WB
31
Bambey 21
0.00
.:::.:.;*
9
1s 86
69N
0.00
3 2
TVX 3236
0.00
10
1s 86
70N
0.00
58-57 x IT81D1137
I
3 3
1~~86
282 N
0.68
11
rs 86
71N
0.00 WB
3 4
E-36
299N
0.00
W B
12
IS.86
72N
0.00
3 5
IS‘86
240N
25.24 WB
13
1s 86
73N
0.00 ASB
3 6
IS;86
253N
0.00
WB
14
1s 86
74N
0.00
3 7
58-57
24.27
WB
15
1s 86
7515
0.00
38
I'r 81~ 1137
0.00
16
SS86
76N
0.00
17
1s 86
77N
0.00 WB
18
ISa86
78N
0.00
Note :
19
. IS86
79N
0.00
WB = WEB BLIGHT
2 0
IS86
80~
0.00 WB
2 1
X86
81~
0.00 WB
ASB = ASHY STEI'4 BLIGHT
2 2
13886
82~
0 . '00
2 3
1s 86
83N
0.100 WB
10
The results in table 3 revealed that a11 the 34 entries from
the cross B21 x TVX 3236 and 2 entries (IS86 299N and IS',86 253N) from
the cross 58-57 E: IT81D 1137 were resistant.IS86 282~, another entry
from the same cross showed neglegible infection (0.68%). Out of 4 parents,
3 were free from virus vi2 ; 321, TVX 3236 and IT81 D 1137. 58-57 showed
the highest virus infection (24%).
A third set of 32 entries comprising of 17 breeding lines of
our program and 15 IITA entries received from%FGRL\\D were screened in
the same manner as done in the previous experiments. The sowing was done
on 12.08.87 and inoculation on 27.08.87. However, the disease develop-
ment was poor in this tria1 which was evident from the poor infection on
the spreader rows,All the test entries were free from virus.
A set of 5 varieties were also grown in the same field alongwith
the above screening trials. Though these varieties were not artificially
inoculated, some of them showed a very high incidence of virus infection,
B21 and TVX 3236 were free of virus while amongst the susceptibles inclu-
ded Casa 3 (25%), 58-57 (60%) and 59-9 (83%).
. . . :
:.. :.
11
42 entries comprising of 38 breeding lines from advance trials
and 4 check varieties were screened in the screeen house during Sept-Oct
1987. About 6 seeds of each entry were sown in separate pots. The inocu-
lation was done on 26.09.87 and repeated on 28.09.87. The inoculum was
prepared from the infected leaves of 58-57 collected from Bambey. The
methods of preparing inoculum and inoculation were the same as used pre-
viously and doscribed in the beginning of the report. The symptoms started
appearing in the first week of october. The reactions noted on 17.10.87
are presented in table 4.
Tablee 4 : Screen house reactions of entries from Advance Trials
Entry
Reac tion
Entry
Reaction
In,.Tr
235 N
R
IS86
2NN
R
-“_
245 N
S
1'
- -
76 N
R
-“_
247 N
R
1‘
- -
93 N
R
-“_
252 N
R
-"_
114 N
S
- “_
269 N
R
- "_
168 N
R
- ” -
276 N
R
1,
- -
185 N
S
_“_
283 N
R
-f’-
217 N
R
-“_
292 N
R
-“_
224 N
R
.
VI
- “_
309 N
S
- -
237 N
R
- “_
310 N
R
-)‘-
241 N
R
- “_
239 N
R
-“_
253 N
R
-“_
259 N
S
- ” -
174 N
R
-“_
279 N
R
-1’ -
191 N
S
-“_
286 N
R
-“_
218 N
R
-“_
299 N
R
-II-
219 N
S
-“_
36 N
R
-“_
248 N
R
- “_
48 N
S
-1’ -
2'75 N
R
-“W
63 N
R
58-57
S
- ‘1-
121 N
R
TVX 32 36
R
B”_
140 N
R
Mougne
R
- “_
170 N
S
B 21
R
Notes : R = Resis.tant
S = Susceptible
12
The results indicated that quite a large number of entries did not show
virus infection. Out of 38 breeding lines 29 were resistant and 9 suscep-
tible. Amongst the check varieties 58-57 showed susceptible reaction while
TVX 3236, Mougne and B21 were free of virus infection.
During the subsequent observation taken on 27.10.87 entry n’EF36
23935 was found susceptible,All other reactions remained the same.
13
1.2. Multiple disease screening nursery
Screen:ing the germplasm varietizagainst principle cowpea di-
seases was continued at Bambey during this year also. In a11 243 germplasm
varieties comprising of mostly local collections and few varieties ob-
tained from International Institute of Tropical Agriculture,Ibadan
(Ni-
*
geria) were screened against major diseases such as bacterial blight,
virus, choanephora pod rot, web blight, ashy stem blight and cercospora
leaf spots. The disease nursery consisted of spreader rows,indicator rows
and the test entries. Two varieties were used for spreader and indicator
rows viz. Bambey 21 (bacterial blight susceptible) and 58-57 (virus sus-
ceptible).Half line was sown to B 21 and the remaining half to 58-57. One
line of these susceptible varieties was sown on 20.07.87 as spreader row
every after 4 test entries. Thz sowing of test entries was done on 28.07.87.
One line of indicator rows was sown on the same day every after 2 test
entries. One line of L1.5 m length was sown to each test entry. The spacing
between 2 lines was 80 cm while between 2 plants was 50 cm. Thus there
were 10 pockets in each line of which 5 were sown to B 21 and 5 to 58-57
“.: . .
in case of spreader and indicator rows. Each test entry was repeated twice.
A border of 4-6 lines of B 21 and 58-57 was sown a11 around the experimen-
ta1 plot. A suspension prepared from bacterial blight infected leaves
of 1986 rainy season was sprayed on the experimental plot on 27.08.87,
58-57 plants in the spreader rows were inoculated with virus on 31.08.87.
The inoculum was prepared by blending the infected leaves collected from
seed multiplication plot of 58-57 at Bambey during 1987 rainy season in
a buffer solution of sodium and potassium phosphates.
The virus infection on the spreader rows was satisfactory.
However , it did not spread to test entries,Cnly six test entries developed
virus infection. Similarly bacterial blight incidence was also very low.
Only 17 entries showed bacterial blight infection. This may be due to
very high natural infection of web blight and ashy stem blight in the
disease nursery plot which night have suppressed the bacterial blight and
virus infections. Incidence of choanephora pod rot was also low. The cer-
cospora leaf spot infection developed at late stage and was seen ~,ostly
on late entries. The observations on a11 the diseases are summarised in
t a b l e 5.
14
Table 5 : Summary of results on infection of major diseases
(Average of 2 replications)
_ .
--
I
. ;. \\’ INP I
W B
1 ASB 1 VR 1 BB
l
C R
I
CPR
Ch-N' 1
- -
I
l INC ' INT ' INC ' INC ' INC ' INT ' INC ' INT ' INC ' INT
1
58-57
1 0
0
0
0
11
0
0
0
0
0
0
2
58-39
2 2
1 0
3.0
0
0
1 0
3
0
0
0
0
3
58-24
9
100
100
5 0
0
2 5
7
0
0
0
0
4
59-12
32
17
1.7
9
0
0
0
8
2
0
0
'5
~9-1-12-12
18
3 8
1.6
9
0
9
2
0
0
0
0
6
78-45
1 2
5 0
2
0
0
0
0
0
0
0
0
7
Jan Haoussa
7
55
52
0
0
0
0
0
0
0
0
8
66-71
3 2
3 4
34
34
0
0
0
0
0
0
0
9
58-161
1 4
2 0
315
2 0
0
0
0
0
0
0
0
10
60-2
29
12
311
9
0
0
0
0
0
0
0
II.1
78-1
17
6 4
60
59
0
0
0
0
0
0
0
12
58-152
7
6 2
3 9
3 6
0
0
0
0
0
7
1.5
'13
78-44
29
35
30
2 5
0
0
0
0
0
0
0
'14
59-32
2 9
5 0
50
5 0
0
0
0
0
0
0
0
'15
84 E-l-lot
3 0
4 0
1+0
4 0
0
9
‘1
0
0
0
0
s.6
CT 81~1032
1
0
0
0
0
0
0
0
0
0
0
17
59- '2.9
2 1
32
30
18
0
0
0
0
0
0
0
18
58-185
2 4
2 2
2 2
0
0
0
0
0
0
0
0
19
Cvu 69
1 6
60
3 4
2 5
0
0
0
0
0
0
0
20
78-7
11
13
:t3
0
0
0
0
0
0
0
0
21
66-68
7
17
8
0
0
l7
4
17
4
0
0
22
POP 735
14
7 5
6 7
6 5
0
0
0
0
0
0
0
>'
9L _3
CB 5
1 2
5 0
'+3
5 0
0
15
4
0
0
0
0
,24
'(3 B24
13
9 2
92
7 5
0
0
0
0
0
0
0
r5
IT82D713
6 190
54
5 0
0
0
0
0
0
0
0
:36
78-9
14
7 3
7 3
7 3
0
0
0
0
0
0
0 *
2 7
casa 16
7
5 8
58
5 0
0
0
0
0
0
4
1
2 8
58-25
6
0
0
0
0
0
0
0
0
0
0
2 9
58-184
6
0
0
0
0
0
0
0
0
0
0
:jo
1
60-3
7
65
1+4
3 0
0
0
0
0
0
0
0
3 :1
18 31
11
ND0
7 5
5 0
0
0
0
0
0
0
0
'i'able 5 : Summary of results on infection of major diseases
(Aveïagc of 2 replications)
--I
-
-
-
-
Enih$
'
NP '
W B
1 ASB 1 VR 1
BB
I
CR
I
CPR
SrN"
I
I INC I IN'T I INC ' INC ' INC ' INT ' INC ' LNT '
INCJ--INT--
- - -
32
Ai 3
2 4
37
20
18
0
0
0
0
0
0
0
33
59-208
16
8 4
7 3
5 4
0
0
0
0
0
0
0
3 4
66-86
2 5
2 6
:t8
0
0
0
0
0
0
0
0
j 35
66-91
2 7
4
4
4
0
8
0
0
0
0
0
/ 34
58-79D,A,
15
2 0
:10
0
0
2 2
11
0
0
0
0
37
78-21
2 4
0
0
0
0
0
0
0
0
0
0
38
63-1
2 6
2 5
2 1
9
0
4
1
7
2
0
0
! 3'3
Pr '7
0
NA
NA
NA
N A
N A
NA
NA
N A
N A
NA
l-r0
8L-Z-ljL
2
0
0
0
0
0
0
0
0
0
0
I+l
66-37
1 6
2 4
:t3
0
0
1 9
2
0
0
0
0
42
81~2814-4
9
17
:17
17
0
17
4
0
0
0
0
43
82-7PRIMA
11
4 7
:34
2 2
0
0
0
0
0
0
0
44
14 ~25
16
8 8
!50
5 9
0
0
0
2 1
7
0
0
45
66-54
18
8 4
67
5 0
0
0
0
0
0
9
2
46
60-9
2 0
5 0
4 1
32
0
0
!O
0
0
0
0
47
78-35
18
4 5
28
1 0
0
1 0
3
0
0
0
0
:$8
AS-5
2 0
4 0
131
2 7
0
0
0
9
7
0
0
'49
AS-2
13
15
'15
15
0
0
0
0
0
0
0
50
58-43
2 3
0
0
0
0
0
0
6
2
4
1
51
67-30
19
5 0
!?O
5 0
0
0
0
6
2
0
0
52
63-33
12
0
0
0
0
0
0
2 5
5
0
0
53
66-l
2 8
71
'52
39
0
0
0
1 2
7
0
0
54
66-149
2 2
5 0
'50
0
0
0
0
9
6
0
0
55
58-80
16
7 6
'73
70
0
0
0
0
0
0
0
56
66-61
7
8 8
;88
8 8
0
0
0
0
0
0
0
57
58-79
19
3 5
.35
2 5
0
0
0
0
0
0
0
58
36-64
2 3
6
3
0
0
0
0
0
0
0
0
59
78-29
32
-,
0
0
0
0
0
0
0
0
0
0
6 0
68-24'
2 1
2 8
16
11
0
0
0
0
0
0
0
61
66-21
19
17
L7
17
0
0
0
2 5
7
C
0
42
TN88-63
2 3
6 6
!Y3
25
0
0
0
8
2
0
0
16
Table 5 : Summary of results 'on infection of major diseases
(Average of 2 replications)
-
-
!
'
!'y
INP I
W B
1 ASB 1 VR 1 BB
I
C R
I
CPR
I
I INC I INT I INC ' INC ' INC ' INT ' INC ' INT I INC I INT
.- . . ..-=
1 44
11
39
34
2 2
0
0
0
0
0
25
7
110 B 33
12
69
32
13
0
0
0
0
0
2 5
1 3
7847
23
1 0
1 0
1 0
0
5
2
8
2
0
0
XL64
2 4
29
9
0
0
4
1
0
0
13
3
16 ~27
8
0
0
0
0
0
0
0
0
0
0
66- 73
1 4
0
0
0
0
0
0
0
0
0
0
58-95
23
0
0
0
0
5
3
8
2
0
0
82-6
25
23
1 8
0
0
5
1
5
1
5
1
1 47
1 4
60
49
1 5
0
0
0
0
0
0
0
12 3 22
1 6
50
22
20
0
0
0
42
11
0
0
58-37
20
22
1 4
11
0
0
0
0
0
0
0
58-16~
29
29
27
2 2
0
0
0
0
0
0
0
58-146
3
100
100
100
0
0
0
0
0
0
0
66-58
28
69
62
40
0
0
.O
0
0
2 9
5
i
78-25
1 7
76
72
50
0
0
0
0
0
0
0
66-74
15
55
36
10
0
0
0
0
0
0
0
13 21
2
100
100
100
0
50
15
0
0
0
0
60-6
6
0
0
0
0
0
0
0
0
25
6
A S 6
25
17
11
0
0
0
0
0
0
0
0
81D 83~
1 6
34
25
0
0
0
0
0
0
0
0
AS 9
1 6
1 4
9
0
0
0
0
0
0
0
0
85 F 962-4 27
4
4
0
0
0
0
0
0
4
1
78-23
28
25
1 3
0
0
0
0
0
0
0
0
59-24 Dl
28
58
55
1+0
0
0
0
0
0
0
0
66-14
29
3 1
28
cl7
0
0
0
0
0
4
1
58-153
22
1 8
11
9
0
0
0
0
0
1 3
3
60-l
23
38
34
27
0
0
0
0
0
13
3
83-D-328-4'-=
4
'1
0
0
0
0
0
0
0
0
1 94
3 1
54
4 1
30
0
0
0
0
0
0
0
58-74 Dlc,. 2 6
1 5
1 2
0
0
0
0
4
1
4
1
7
17
'!'able 5 : Summary of results on infection of ma or diseases
(Average of 2 replications)
.-
-ÏI Entry LJP I WB
1 ASB 1 VR 1 BB
I
C R
I
CPR
l
I
INC I INT I INC ' INC ' INC ' INT ' INC ' INT ' INCINT
-
__
58-181
6
100
100
88
0
0
0
0
0
0
0
i 59-25
20
90
88
80
0
0
0
0
0
0
0
58-154
25
50
4 3
40
0
0
0
0
0
0
0
58-30
22
91
8 0
42
0
0
0
0
0
0
0
58-74
35
2 2
1 6
7
0
0
0
0
0
0
0
Lç^ 16xBZlx
21
73
51
3 6
0
0
0
0
0
0
0
1137
POP 736
25
79
73
58
0
0
0
0
0
0
0
58-109
20
50
50
50
0
0
0
23
11
0
0
"1 -4.7
15
86
86
86
0
0
0
0
0
0
0
59-5
25
42
35
1 5
0
0
0
0
0
0
0
58-58
2
0
0
0
0
0
0
0
0
0
0
58-44
33
3
1
0
0
0
0
0
0
0
0
I 86~R7
1 4
17
13
9
0
0
0
0
0
0
0
58-191
27
23
1 8
1 4
0
0
0
5
1
cl
0
66-27
26
44
4 4
25
0
0
! 0
0
0
0
0
cgb12
19
43
34
22
0
0
0
0
0
0
0
66-51
2 0
40
38
35
0
0
0
0
0
0
0
58-161
26
29
29
25
0
0
0
0
0
0
0
66-38
2 2
45
42
11
0
0
0
0
0
0
0
ii2-2-13
0
N A
NA
NA
NA
NA
NA
NA
NA
NA
NA
58-155
13
88
67
88
0
0
0
0
0
0
0
58-81
23
16
16
8
0
0
0
0
0
0
0
Y’4 S 2246- 4
22
6 2
42
5 2
0
0
0
7
2
0
0
tx-53
13
37
37
29
0
0
0
0
0
0
0
78-46
24
0
0
0
0
0
0
0
0
0
0
58-32
35
27
2 4
19
0
0
0
0
0
0
0
58-185 Y
25
7
7
7
0
0
0
0
0
0
0
'ii 1 - .,5*7
15
22
2 2
? ?
0
0
0
0
0
0
0
58-162
32
36
29
2 1
0
0
0
0
0
0
0
78-6
2 0
0
0
0
0
0
0
0
0
0
0
Table 5 : Summary of results on infection of major diseases
(Average of 2 replications)
-
-
-
.r: tr-;;
'NP I
W B
1 ASB 1 VR 1 BB
I
C R
I
CPR
--
SrN ’
I
' INC I INT 1 INC ' INC ' INC ' INT ' INC ' INT ' INC ' INT
123 j TVX :32-36
1 4
0
0
0
0
0
0
0
0
0
0
i24 j '78-32
2 6
0
0
0
0
0
0
0
0
10
3
s25 1
9 -19
I 24
0
0
0
0
0
0
0
0
0
0
:126
58-47
1 0
1 0
1 0
10
0
0
0
0
0
0
0
:l 27
63-8
29
0
0
0
0
0
0
0
0
5
1
:128
66-56
28
0
0
0
0
0
0
0
0
9
3
:i 29
58-21
19
10
3
0
0
0
0
0
0
JO
0
:1 30
58-221
1 4
1 7
17
0
0
0
0
0
0
00
0
:1 31
66-46
24
12
8
1 2
0
0
0
0
0
0
0
‘132
58-79T
18
90
85
0
0
0
0
0
0
14
4
133
B 32 ID
1 4
57
50
54
0
0
0
0
0
0
0
134
59-95
21
90
8 6
61
0
0
0
0
0
0
0
1.35
VE 78-42
19.
‘67
66
69
0
0
0
0
0
“0
0
136
66-77
22
50
50
50
0
0
0
0
0
4
1
J 37
58-19
29
1 9
14
1 0
0
0
0
0
0
00
0
138
58-64
23
7
4
0
0
0
0
0
0
0
0
139
58-17
2 9
‘85
9’7
4.7
0
0
0
0
0
0
0
3.40
58-50
1 8
89
7 4
62
0
0
0
0
0
0
0
3. 41
58-60
19
1 3
13
0
0
0
0
2 2
7
0
0
142
78-42
1 6
ï.5
15
15
6
0
0
0
0
17
4
; 1.43
78-36
2
0
0
0
50
0
0
50
13
0
0
j 1.44
63-5
21
0
0
0
0
0
0
0
0
0
0
1 145
78-5’
1 3
0
0
0
0
0
0
0
0
0
0
/
j 1.16
66-39
1 8
88
78
75
0
0
0
0
0
0
0
l
; 2.47
59-20
26
1 7
17
0
0
0
0
0
0
11
3
j :.‘-18
’
66-67
23
29
29
1 5
0
0
0
0
0
0
0
i 149
82-9
9
0
0
0
0
0
0
0
0
l
J
0
0
/ 1.50
IAR-48
8
50
?lO
50
0
0
0
2 2
6
0
0
I1 151
58-16 Dl
100
00
72
0
0
0
0
0
0
JO
0
; 1.52
84 D" 371
30
J.6
1.6
0
0
0
0
0
0
0
0
153
58-15
2 4
53
50
3 1
0
0
0
0
0
00
0
19
Table 5 : Summary of results on infection of major diseases
(Average of 2 replications)
-
- *. ‘NP 1 WB
1 ASB 1 VR 1 BB
C R
I
CPR
%>No 1
I
' INC ' INT ' INC ' INC ' INC I INT
INC ' INT ' INC ' INT
-
I
- -
154
66-62
8
17
17
17
0
0
0
0
0
0
0
155
67-95
2 4
6 3
6 0
32
0
0
0
0
0
0
0
.156
58-52
21
72
5 7
2 8
0
0
0
0
0
0
0
'157
1 31
2'0
7
7
7
0
0
0
0
0
0
0
158
58-55
2 6
43
215
14
0
0
0
9
2
9
2
159
78-22
30
2 9
29
2 9
0
0
0
0
0
0
0
S60
78-39
2 4
31
3; 1
2 9
0
0
0
0
0
0
0
'161
66-52
2 8
9 7
9 5
6 8
0
0
0
0
0
0
0
i62
58-10'7
2 8
53
419
34
0
0
0
0
0
0
0
163
60-8
13
9 3
9 3
9 3
0
0
0
0
0
0
0
164
67-167
21
50
50
50
0
0
0
0
0
4
2
1.65
66-45
2 7
50
50
50
0
0
0
0
0
0
0
1.66
66- 89
13
8 6
8 4
7 9
0
0
0
0
0
0
0
16’7
59-30
2 8
7 5
6 9
4 8
0
0
0
0
0
'0
0
!
168
34s 2231-1
2 6
47
4 4
4 4
0
0
0
0
0
0
0
169
58-5
2 4
3 5
3 5
3 4
0
0
0
0
0
0
0
1.70
78-37
2 3
17
3.4
0
0
0
0
0
0
0
0
371
58-79D2B
24
s‘y
' '7p-
fo
0
0
0
0
0
0
0
172
66-12
2 5
7 4
6 5
5 8
0
0
0
0
0
0
0
1.73
78-26
2 7
50
50
50
0
0
0
0
0
0
0
174
58-185 D
2 8
50
4 6
3 5
0
0
0
0
0
0
0
175
58-12
2 4
4 0
3 5
30
0
0
0
0
0
0
0
376
66-59
17
43
217
2 2
0
0
0
0
0
0
0
177
67-166
18
39
32
34
0
0
0
0
0
0
0
178
58-74T
19
7 9
7 5
6 4
0
0
0
0
0
0
0
1.79
66-63
11
70
6 3
52
0
0
0
0
0
0
0
1.80
15
!r,
5
0
0
0
0
0
0
0
2-81
50
50
50
0
0
0
0
0
0
0
182
47
4 6
41
0
0
0
0
0
0
0
383
8 5
7 9
70
0
0
0
0
0
0
0
2 0
Table 5 : Summary of results on infection of major diseases
(Average of 2 replications)
!il.I’J
'NP '
W B
1 ASB 1 VR 1 BB
I
C R
I
CPR
I,
I INC I IN?-' I INC ' INC ' INC ' INT ' INC ' INT I INC I INT
-II - _ .--
1
184
78-2
2 1
29
22
29
0
0
0
0
185
67-32
3
00
00
00
0
0
0
0
186
59-26
2 4
69
61.
42
0
0
0
0
187
58-151
13
54
40
16
0
0
0
2
188
66-36
2 6
84
84
7 5
0
0
0
0
189
59-13
2 5
43
38
19
0
0
0
0
0
0
0
190
66-A4
3 0
22
13
00
0
0
0
0
0
0
0
191
78-10
30
0
0
0
0
0
0
0
0
0
0
192
66-17
18
0
0
0
0
0
0
7
;'
0
0
193
15 B 26
8
0
0
0
22
0
0
0
0
0
0
‘,;
194
66-22
3 0
32
32
32
7
0
0
16
4
0
0
195
Ndiambour
7
0
0
0
17
0
0
0
0
17
4
196
58-95 D2
2 5
0
0
0
0
0
0
0
0
0
0
197
82-10 ML
11
46
23
0
0
0
0
0
0
6
0
I
198
78-40
2 1
22
18
15
0
0
0
0
0
7
2
199
IT8iD1137
2'
0
0
0
0
0
0
0
0
0
0
200
66-76
15
0
0
0
0
0
0
0
0
0
0
201
58-40
9
48
3:;
2 5
0
0
0
40
20
0
1 0
202
'78-20
19
17
4
0
0
0
0
0
0
0
0
203
78-16
16
50
50
5 0
0
0
0
0
0
0
0
204
59-9-Dl
31
17
4
0
0
0
0
0
0
0
0
:
205
68-226
3 2
11
.3
0
0
0
0
0
0
0
0
206
78-26
35
0
0
0
0
0
0
0
0
10
2.5
2i!7
VLP Casa 16
28
4
4
4
0
0
0
0
0
0
0
208
58-28
22
7
7
7
0
0
0
0
0
0
0
209
TVIJ-662
23
55
4 2
43
0
0
0
0
0
0
0
210
S:i 328
4
25
13
0
0
0
0
0
0
0
0
<
211
182 VITAc>
27
0
0
0
0
0
0
0
0
10
1
212
'j8-74DlAR
18
20
20
2 0
0
0
0
0
0
8
2
213
78-8
19
22
2 2
2
0
0
0
0
0
5
2
214
58-2
16
15
9
7
0
0
0
0
0
0
0
21
Table 5 : Summary of results on infection of ma or diseases
(Average of 2 replications)
---
2 3.5
66-55
75
66
63
0
0
0
0
0
0
0
213
58-20
29
25
0
0
0
0
0
0
0
0
2 1'7
78-33
36
3 1
0
0
0
0
0
0
0
0
218
83-122
50
4 4
0
0
0
0
0
0
3 4
9
219
58-34
2
50
13
0
0
0
0
0
0
0
0
220
Mougne
1 0
40
3 5
0
0
0
0
0
0
0
0
2î 1
78-46
2 4
1 9
14
1 0
0
0
0
1 9
5
0
0
222
78-3
2 6
0
0
0
0
0
0
0
0
0
0
223
66 -40
2 2
0
0
0
0
0
0
0
0
0
0
224
fj9-24T
17
58
4 3
37
0
0
0
0
0
0
0 .
22'5
103-6
24
13
3
0
0
0
0
21
5
0
0
226
58-75
2 2
4 2
7.5
0
0
0
0
0
0
0
0
22.7
66-129
2 5
9 2
8 4
30
0
0
0
0
0
0
0
228
78-31
2 5
00
4 3
100
0
0
0
0
0
0
0
Lî9
78-24
2 4
50
14
45
0
0
0
12
3
0
0
2 -jo
67-159
1 7
00
9 2
66
0
0
0
0
0
0
0
22, 1
;~TVU 3629
3i
66
6 0
39
0
0
0
0
0
0
0
2 a :I>
., .-
IT 82D 716
8
“jq
4::
17
0
0
0
0
0
0
0
23 3
85F 898- 5 35
28
23
20
0
0
0
0
0
0
0
23
78-30
29
42
36
18
0
0
0
0
0
0
0
.’
23
66-48
24
19
1 9
16
0
0
0
0
0
0
0
2%
J
78-15
21
18
18
18
0
0
0
0
0
0
0
22, 7
58-42
1 2
38
38
3 8
0
0
0
0
0
0
0
2 3, S?
‘C 21
21
1 7
1 5
9
0
0
0
0
0
0
0
23
58-53
1 9
1 4
6
4
0
0
0
4
1
0
0
24.9
-r. 22
24
2 6
2 2
16
0
0
0
0
0
0
0
241
78-43
2 1
4 5
43
39
0
0
0
0
0
0
0
242
00
89
6 2
0
0
0
0
0
0
0
243
6 9
5 2
4 8
0
0
0
0
0
0
0
NOTE
WB -- Web blight ; ASB - Ashy stem blight
VR -- Virus
; Bit - Bacterial blight
CR -- Cercosporiose
,CPR-Choanephora
pod rot '
INC - Incidence : INT - Intentity
NA -- Data not available
NP -- Number of plants observed
2 2
From the results of table 5 it is seen that only 37 entries were
free from web blight infection while 204 entries were observed to be sus-
ceptible.
Seven entries including B 21 which was used in the spreader
rows exhibited 100% infection. This indicates the high level of disease
pressure in the nursery plot. Ashy stem blight infection was observed on
162 entries while 79 were free. The infection of this disease also was
very severe. Many B 21 plants in the
spreader and indicator rows were
completely killed by ashy stem blight. Due to very high pressure of both
web blight and ashy stem blight, the’
development of other diseases was
poor. Only 6 entries showed virus infection while 17 entries exhibited
bacterial blight infection. Infection of cercospora leaf spot appeared
late and was developed on 34 entries. Choanephora pod rot was also compa-
ratively poor and was seen on 31 entries only. In the whole nursery 23
entriegwere observed to be free
f’rom a11 diseases, However, 9 entries
had very poor plant stand (less than 10 plants). As such the final list
of the renaining14 varieties which did not show any disease infection is
a s under.
78-21, 78-29, 66-73, 78-46, 78-6, TV x 3236, 79-19, 63-5, 78-5, 78-10,
58-95 D2, 66-76,78-3 and 60-40.
1.3. Screening for bacterial blight resistance.
A set of 55 entries comprising of 51 breeding lines and four
parents were screened against bacterial blight in the screen house. Four
to five seeds of each entry were sown in each pot separately on 21.10.87.
The inoculation was carried out on 30.10.87 by the stem stab method des-
cribed in 1985 report. The observations for the bacterial blight score
were recorded on 20.11.8’7, u-12-.87 and 28.12.87 in 1 to 10 scale as
described in 1986 report. The results of this screening are presented in
table 6.
23
Table 6 :
-
-
Bacterial Wght reactionsof sonebreeding lines and pzents
in the screen house.
Entry
1 Score 1 Entry 1 Score 1 Entry 1
Score
1
Entry
1
Score 1
Entry
1
Score
,-'
Primary Tria1 1.
TVX3236 x B21 F6
1:s 8 7 313 N
1
1
1 314 N 1
1
1 315 N(
1
1 316 N 1
1 317 N 1
318 N
1
1
1 319 N 1
10
1 320 N13/10,1/4 1 323 N 1
1 324 N 1
325 N
1
NC
1 326 N 1
1
I327N(
3
1 328 N 1
1 329 N 1
I
l
I
I
I
I
I
I
I
B21 x IT 81D 1137 F5
I 332 NI 1
I 333 N I
I
334 N
1
1
330
335 N
I
I 1/6,2/1
1
I
I 331
336 N I!
1:
I
I
I
, 337 N 1
I
I
338 N
I
339 N
1 NG
340 N
I
11 341 N I3/lO,Y8'
342 N' 1
I 343 N I
I 344 I
N
I
I
I
1
345
I
I
N
1 1
I-
I
TVX 3236 x VCS 14 F6
434 -N
I
NG
I 435 N I NC
I
-1
I
I
I
I
TVX 3236 x TVU 1174 F6
350 N 1
1 1 351 N i
1 352 NI ‘1
1 353 N 1
1 354 N 1
1
355
,. :
N 1
NG I
I
I
I
I
I
I
I
:.; ::
Advance Tria1 II
Mougne x TVU 1174 F7
2NI
11
1
I
I
58-57 x TVU 1174 F6
185 N 1
1 1 168 NI 1
1 217 NI 1
1 22tiN 1
I
I
24
Advance Tria1 III
-
-
-
-
B 21 x TIJ~ 3236 ~6
63~
i
58 - 57 x TVY 1174 F 6
170 N 1
174 N
.-
1
191 N
NA
218 N ;
2l9N
7
58 - 57 x 1T81 D 1137 F 6
1586275 N
1
Parents
B 21
10
Mougne
1
58-57
1
TV x 3236
::
Note : NC = No germination
:.
NA = Reaction not available
The results in table 6 indicated that many breeding lines possess resistance
co bacterial blight. Out of 51 breeding lines, 34 remained free from bacterial blight
infection, 3 showed resistant reaction,l was moderately resistant,2 moderately susceptible,
1 susceptible, 2 highly suscep tible and 2 exhibitted heterogenous reaction. Amongst the va-
'Letles B 21 was 'Iighly susceptible while Mougne, 58-57 and TVX 3236 remained free.
25
II. Virus transmission studies
-
-
;::,:
.',..
4..
The literature shows that some of the viruses are transmitted
through seed. The common viruses prevailing in Senegal such as aphid-borne
mosafc virus andsoutherm bean mosaîc virus are reported to be perpetuated
through seed. Similarly there are reports indicating transmission of
virus by insects. Aphid-borne mosaîc virus is reported to be transmitted
by aphids? Anhis craccivora ,While beetlas Ootheca mutabilis are reported
to be responsible for transmission of southern bean mosalc virus. In
order to find out the extent of virus transmission through seed as well
as by insects some filler trials were conducted during 1987 trop season,
the results of which may help to determine the gravity of the problem
and to take suita'ble measures to check this transmission.
2.1. Transmission through seed.
This tria1 was conducted at Bambey on 58-57 variety;There were
two treatments. In the first treatment seeds collected from the virus
infected plants were used while the second treatment consisted of healthy
seeds collected from virus free plants.
Each treatment was sown in 5 x 2 m2 plot (4 lines of 5m lengh)
with a spacing of 50 x 50 cm2. Each treatment was repeated 4 times. The
sowing was done on 20.07.87,~he observations were recorded on 4.08.87
for the number of virus infected plants. Al1 the plots sown with healthy
seed did not show any virus infected plant, while the plots sown with
infected seeds showed 10 to 22% virus infected plants. The average was
17.5% which is quite high. This shows the seriousness of the problem and
emphasizeo :he need of hec,lthy seed production.
"
:
1.2 :
26
2.2.
Transmission by insects :
This tria1 was conducted attwo locations viz ; Bambey and Dji-
belor on 58-57-The tria1 consisted of two treatments : 1) Protection of
plants from insects using appropriate insecticide. 2) No protection.
Thimul 35 8OOg ai/ha was usad for protecting the plants against insects.
The incidence of aphids was noticed at Bambey which is a vector for aphid
borne mosalc virus. At Djibelor cowpea beetles were observed which serve
as vector for southern bean mosaîc virus.
The tria1 at Bambey was sown on 20.07.87.0.bservations
were
recorded twice in both protected and unprotected plots for virus incidence.
In the first observation noted at Bambeyy on 4.û8.87 it was revealed that
there was no virus in the protected plots while the unprotected plots
showed 9.64% virus incidence (Mean of 4 replications). There was conside-
rable increase in the virus incidence at the time of second observation
:,hich was taken on 25.09.87,unprotected
plots showed 20% virus incidence
(Average o f 4 replications ) Protected plots also showed 4.37% virus inci-
dence. This increase in the virus incidence indicated that the aphids
prevailing in the tria1 plot
were responsible for transmitting the virus
infection to the healthy plants. The virus incidence in the protected
plots may be because the insects had already transmitted the virus before
they were killed by the insecticide.Similar trend of results was noticed
at Djebelor also..The tria1 was sown on 12.08.87. First observation on
virus incidence was taken on 27.08.87 which. revealed very neglegible
infection in the unprotected plots. The protected plots did not show
any virus infection. The second observation which was taken on 25.09.87
revealed that the mean virus incidence in the protected plots was 16.5%
while it was 27.1% in unprotected plots.
The f’irst observation taken 2 weeks after sowing showed little
virus infection at both the locations which might have been transmitted
through seed.
27
But the subsequent increase observed in the second observation was c!ue to
transmissio?
of virus by vectoïs. The high incidence in the -,ocond observa-
tion indicates +hsY Insects -3.e.y an active role in the spread of virus.
III. Estimation of losses in yield due to major diseases.
3.1. Due to bacterial blight :
A filler tria1 was conducted at Bambey to estimate the probable
loss in yield caused due to bacterial blight.The :;rial was conducted on B 21
and consisted of two Vreaknents .l)plots with minimal disease infection by use
of healthy seed and 2)glots with maximum disease infection by use of infected
seed and inocl!latLon of -1ants. The sowing was dcne -on 23.07.87 in -5 ‘x 2m2
plot ( 4 lines,of 5n length ? f o r each t r e a t m e n t w i t h 4’ replfcations. .
The inoculation for maximising the disease infection was done on 27.08.87
by injecting the bacterial suspension in the leaves by infiltration tech-
nique. The observations were recorded for disease infection and the yield
data.
Thedisease intensity in the minimal disease infection treatment
.-
(uninoculated plots) ranged from 1.4’7 to 10.71 with an average of 5.61.
While the disease intensity in the maximum disease treatment (inoculated
plots) varied from 13.75 to 27.38 with an average of 21.22.
The yield data showed that there was reduction in yield in the
inoculated plots than the yield in uninoculated plots. The yield figures
in the inoculated :plots ranged from 3~18 to 565 Kg/ha with an average of
440 Kg/ha, while the yields of uninoculated plots were in between 490 to
912 with a mean of 713 Kg/ha. Thus there was 38.29% (273 Kg/ha) reduction
in yield due to more bacterial blight infection in the inoculated plots.
3.2. Due to virus.
Another Piller tria1 was conducted at Bambey and Djibelor to
estimate pro’bable loss in yield caused due to virus. The tria1 was conduc-
ted on 58-57 at both the locations.
28
There were two treatments 1)plots with minimal virus infection through
use of healthy seed and control of vectors and 2) plots with maximum virus
infection through use of infected seed and artificial inoculation of plants.
The Bambey tria1 was sown 20.07.87 in 5 x 2m2 plot for each
treatment replicated 4 times. The inoculation for maximising the virus
infection was done on 31.08.87 with the sap collected from the infected
plants. Same inoculation method as described in 1.1 was adopted. Observa-
tions were recorded for virus incidence and the yield.
The final observation recorded on 25.09.87 showed 10% virus
incidence in the uninoculated plots while 38.75% in the inoculated plots.
The average yield obtained in uninoculated plots was 603 Kg/ha while ino-
culated plots gave average yield of 498 Kg/ha.Thus there was 17.41%
(105 Kg/ha) loss in yield due to more virus infection in the inoculated
plots.
The Djibelor tria1 also showed the similar trend of results.
The tria1 was sown on 12.08.87 with the same plot size and replications
as that of Bambey trial,Virus inoculation in the inoculated plots for
maximising infection was done on 27.08.87 with the sap collected from
infected leaves as per the procedure described in 1.i. Observations were
recorded for virus incidence and the yield.
Uninoculated plots showed 17.78% average virus incidence in the
final observation taken on 25.09.87 while the inoculated plots showed
38.13%. Very low yieelds were obtained in both the plots. However,the
trend was the same.
29
IV. Identification of seed microflora and their control :
Some of the pathogens on the seed cause seed rot or root rot
resulting in very poor stand of the trop. This is observed invariably in
B 21 variety. Hence studies were under taken to identify the pathogens
attacking seed which resulted in seed rot / root rot and their control.
Seeds of 3 varietes viz B 21, 58-57 and Mougne were used for
these studies. The seeds were treated with Granox (4g/Kg), Benomyl (lg/Kg),
and Thiram (2g/Kg). One set of untreated served as control,Seed.microflora
was detected by rolled towel method. Seeds were put on sets of three
blotter sheets previously moistened with water. The sheets were rolled
and kept at room temperature. The sheets were opened after 10 days and
the observations were recorded for seed rot and root rot/ seedling in-
fection. The microflora associated with seed rot and root rot/ seedling
infection was examined under the microscope. The results are presented
in table 7.
i
Table 7 : rieed rot and root rot in seed of 3
cowpea varieties.
Variety
Seed
seed .rqt
[Healthy
root
Organisms isolated
treatment
(ungerminatedjseed germi rot %
from seed rot/root rot
%
Inated %
B 21
Control
61
23
16
Macrophomina phaseolir
(=Rhizoctonià bataticc
la)
Fusar-ium equiseti,
Fusarium sp; Penicil-
lium sp, .RhizwF
.Er&.&. -SP' 1
?
çr ranox
16
84
0
?
Benomyl
2 4
7 6
0
Thiralm
35
50
15
Macrophomina phaseolir
5%~57
Control
11
%9
0
Penicillium .sp,colle-
t o t r i c u m
capsici, Curvu_laria si
a-nia- sp
,z:.. :
Granox
0
100
0
Benomyl
0
100
0
Thiram
0
100
0
Mougne
Control
5
72
23
Rhizopus $p,As~~gill:
Spmophomina
phaseoïina
Benomyl
5
93
2
Rhizopus sp,Macropho-
&.na phaseôlina,
Granox
0
100
0
ErXnia
Thiram
5
91
4
Fhizopus sp,Penicilli
sp, MacroPh&x
-
The results in table 7 indicate that B 21 was more prone to infection of fungi
causing seed rot/root rot than 58-57 and Mougne. In B 21 seed dressing with Granox
and Benomyl reduced these diseases more effectively than Thiram. In case of 5iJL57
a11 three fungicides showed equal efficacy probably due to the fact that this varie
seed was less infected, while in case of Mougne,Granox was most effective with no
seed or root rot followed by Benomyl.
V. Survey of cowpea Diseases :
-
-
During 1987 rainy season, natural infection of ashy stem
blight and web blight was very severe. Both the diseases were seen at
a11 the locations and in almost a11 the trials. On Farmers’ fields
also these two were the main diseases encountered. Inccdence of bacte-
rial blight and virus was as usual on B 21 and 58-57 respectively .
Incidence of bacterial blight was quite high on B 21 at Nioro.Choane- -
phora pod rot was minor. Cercosporiose was noticed mostly on midlate
and late varieties at the end of trop cycle. The striga incidence at
Kebemer was comparatively more,58-57, which is reported to b?
resistcnt,
was also found to be altacked by striga. Stationwise
report of various
diseases encountered in the experimental ,nlots at the research stations
as well as minikit triais on the farmers’ fields is furnished in table 8 .
).’
‘..
Table 8: Cowpea diseases encountered during 1987 rainy season
Research Stations :
Bambev
Ashy stem blight : - B 21, 58-57, CB 5, TVX 3236 and many breeding lines
Rhizoctoniose
: B 21, CB 5, 58-57 and some breeding lines
Virus :
: 58-57, Ndiambour
Bacterial blight: B 21, CB 5
Choanephora >od rot : B 21, CB 5, 58-57
Cercosporiose
: B 21, 58-57
..:<:
These diseases were also noticed on some of the germplasm entries
in the disease nursery (sec table 5 of this report).
Ndiémane :
Ashy stem blight : B 21, 58-57, TV x 3236,
Mougne and some breeding lines
Rhizoctoniose : B 21
Nioro
RhSzoctoniose : B 2 1
Bacterial Blight : B 21
Virus : 58-57
32
Djlbelor
Virus : 58-57 ; 59-9 ; Casa 3
Web blight & ashy stem blight was seen on some of the breeding
lines.
Thilmakha
Ashy stem blight : B 21 ; 58-57; TVX 3236
Mougne and some breeding lines
Rhizoctoniose
- B 21, Mougne, 58-57, TVX 3236 and some breeding lines
Cercosporiose - 5’8-57 and few late breeding lines
Choanephora pod rot : B 21, 58-57, Mougne and few breeding lines
Choanephora pod rot incidence at Thilmakha was comparatively more
than Bambey.
Louga
Ashy stem blight n- B 21, CB 5, 58-57, TVX 3236
Rhizoctoniose-B 21, CB 5
Virus - 58-57
Bacterial blight-13 21, CB 5
Minikits
Sam Thialle
B 2 1 - bacterial blight, ashy stem blight, web blight, choanephora pod rot
Mougne - Ashy stem blight, web blight,choanephora pod rot, cercosporiose
58-57 - Virus,Cercosporiose,choanephora pod rot, web blight, ashy stem blighs.
TVX 3236 - choanephora pod rot, web blight, ashy stem blight
Sagatta :
B 21 - Rhizoctoniose, bacterial blight, ashy stem blight
GB 5 - bacterial blight, Rhizoctoniose
58-57 - Virus,cercosporiose
Ndiambour-choanephora pod rot
Thilmakha
B 21 - Bacterial blight, web blight, ashy stem blight, choanephora pod rot
TVX 3236 - Ashy stem blight, web blight
58-57 - Virus, cercosporiose, web blight, ashy stem blight,choanephora pod rot
33
Piougne- Web blight, ashy stem blight, cercosporiose, choanephora pod rot.
Xcur 3oumi
GB 5 - Rhizoctoniose, bacterial blight, ashy
stem blight
B 21 - Bacterial blight, Rhizoctoniose, ashy stem blight
58-57 - Virus, cercosporiose, ashy stemblight
Ndiambour - Ashy stem blight
Ngatt
58-57 - Cercosporiose, virus, web blight
B 21 - Bacterial blight, web blight, ashy stem blight, choanephora
pod rot
Mougne - web blight,cercospriose, ashy stem blight, choanephora
pnd rot
Mougne - web blight, cercosporiose,ashy stem blight, choanephora
pod rot
TVX 3236 - web blight, ashy stem blight, cercosporiose
Ndatt Fall
B 21 - Rhizoctoniose, ashy stem blightcbacterial blight
CE 5 - Web blight, ashy stem blight, bacterial blight
58-57 - Virus, cercosporiose
Ndiambour - Rhizoctoniose
Keur galo
58-57 - Virus, cercosporiose, ashy stem blight
T V : ! 3236 - Web blight, ashy stem blight
B 21 - Bacterial bl.ight, web blight, ashy stem blight
Mougne - Ashy stem blight.
34
I;I. Seed Production
-
During 1987 rainy season, seed multiplication plots of different
varieties were inspected periodical1y.B 21 and CB 5 plots were observed to
b e
infected by Rhizoctoniose while 58-57 plot showed some virus infected
.-
plants. In a11 the plots the virus as well as rhizoctoniose infectedplants
were removed to o'btain disease free seed.
OF SENEGAL
.4
___------.
MINISTRY OF RURAL DEVELCIPMENT
1 ,' -'.' :*
DEPAKTMENT OF RESEARCH
_-m-w----
ON CROP PRODUCTION
SENEGALESE .~NSTITU'I'E
-w--m -e---e-
131: .ACRl.CULTURAL RESEARCH
__-_----
ANNUAL REPORT
ON COWPEA
PATHOLOCX - 1987
BY
D.G. (;AIKWAD
-:
NATIONAL CENTRE OF AGRONOMIC
REBEARCI-1 - BAMBM
A disease nursery initiated during 1986 for multiple disease
resistance screening was continued during this year also. There was hea-
vy natural infection of ashy stem blight and web blight in the disease
nursery. This opportunity was taken to score the test entries against
Lhese diseases.Screening
for virus resistance in the field at Djibelor as
well as at Bambey and in the screen house was also continued. Some work
on transmission studies of virus through seed and by insects was initiated.
Similarly experiments for estimation of yield losses due to
virus and bacterial blight diseases were conducted. In the laboratory stu-
dies, attempts were made to examine the pathogens associated with cowpea
seed and seedling rots and their contrôl through use of various seed
dressers. The results of a11 these experiments are discussed in the fol-
l o w i n g p a g e s .
1. Resistance Screening for major diseases.
-
1.1. Screening for virus resistance.
133 individuai plant selections made from 9 F2 families during
1986 rainy season a.t Djibelor were grown at Bambey during off season( Nai?ch-
May ),Natural virus infection was observed on some,. of the lines..Cbserva-
tions of virus incidence on these entries are presented in tablti 1. The
available entries were also screened in the screen house by artificial
inoculation,O-5
seeds of each entry were sown on 2.3.87 in separate pot,
The inoculation was done twice, first on 11.3.87 and the second on 13.3.87.
The inoculum was prepared by blending the infec-ted leaves collected
from
58-57 plot at Bambey during off season in a buffer solution of sodium and
potassium phosphates. Carborundum powder was dusted on the leaves before
inoculation to act as an abrasive. The inoculation was done by rubbing
the primary leaves with a forefinger wetted with the inoculum.
The virus symptoms started appearing in the second week after
inoculation. Final observations were recorded one month after inoculation
and are given in table 1.
Table 1 : Results of virus screening in the field and screen house during
off season.
%
Cross and Entry No
Incidence in
Screen house
the field
Reaction
Casa 16 x B 2;.
1
23 .O8
S
2
14.29
S
3
0.00
N A
4
0.00
NA
5
0.00
NA
6
0.00
R
7
33.33
S
8
0.00
R
9
0.00
NA
10
17.65
S
11
15.35
R
12
20.00
R
13
66.67
NA
14
50.00
S
15
0.00
S
16
36.36
S
17
50.00
NA
18
0.00
NA
19
0.00
N A
59-9 x 321
20
0.00
R
2 1
0.00
NA
2 2
0.00
N A
23
0.00
NA
24
0.00
R
59-q x 0 21
25
0.00
NA
26
0.00
R
27
0.00
NA
28
0.00
NA
29
0.00
R
30
0.00
N A
3
%
Cross and Entry No
Incidence in
Screenhouse
the field
Reaction
I NA
Casa 3 x B21
32
0.00
1 R
33
6.25
I
S
3 4
0.00
I
NA
35
0.00
l
S
36
0.00
I
S
37
0.00
I
R
3 8
0.00
I
R
3 9
0.00
I
NA
40
0.00
I
NA
41 1 0.00
I
R
42 1 0.00
I
NA
43 1 0.00
I
NA
44 1 0.00
I
NA
45 1 0.00
I
R
46 1 0.00
I
R
47 1 0.00
I
S
48 1 0.00
I
R
49 1 0.00
I
NA
50 1 0.00
I
NA
Casa 3 x B21
51 1 0.00
I
S
52 1 0.00
I
R
53 I 0.00
I
NA
54 1 0.00
I
R
55 I 0.00
I
R
56 1 0.00
I
R
57 I 0.00
I
NA
58 1 0.00
I
R
59 I 0.00
I
NA
60 1 0.00
I
R
61 1 0.00
I
NA
62 1 0.00
I NA
63 1 0.00
I
NA
64 1 0.00
I NA
4
%
Cross and Entry No
Incidence
Screenhouse
in the ffield
Reaction
Casa 16 (B 2 1 x 1137)
65
15.56
I
R
66
1 6.67
l
R
67
(38.46
I
S
68
I 0.00
I
R
69
I 0.00
l
R
70
1 4.76
I
S
71
I 0.00
I
S
72 I 0.00
l
R
73
1 0.00
l
S
74
I 0.00
I
S
75 I 0.00
I
R
Mougne (Mougne x 1032)
76 I 0.00
I
R
77 1
6.25
I
R
78 133.33
I
S
79
1 26.67
I
R
80
1 5.88
I
R
81
Ill.76
I
R
82
I 0.00
I
NA
83
I 11.11
I
NA
84
1 0.00
I
S
85
I 0.00
I
R
86
1 5.56
I
R
87
l 0.00
I
S
88
I 0.00
I
NA
89
I 0.00
I
NA
90
I 0.00
I
R
9l
I 0.00
I
R
92
0.00
I
R
93
0.00
I
R
VLP Casa 16 x B 21
94
1 6.67
I
R
95
114.29
I
R
96
123.08
I
R
97
I 0.00
I
NA
98
I 0.00
I
R
99
I 0.00
I
NA
100
I 0.00
I
R
5
%
Cross and Entry N'
Incidence in
Screenhouse
the fiel-d
Qeaction
VLtJ L'asa In x IS'l
L
lU1
.
I
3
102
133.33
I
S
103
I 0.00
I
R
104
~80.00
I
S
105
I 0.00
I
R
106
I 10.00
I
S
107
133.33
I
R
58-57 x TVU 1185
10%
I 0.00
I
R
109.
I 0.00
1 R
110
I 0.00
I
R
111
I 0.00
I
R
112
I 0.00
I
R
Casa 16 x CB5
113
I 0.00
I
S
114
10.00
I
R
115
I 0.00
I
R
116
l 0.00
I
R
ll7
I 0.00
I
NA
1 1 %
I 0.00
I
R
119
I 0.00
I
R
120
I 0.00
1 R
121
l 0.00
l
S
122
I 0.00
I
R
123
I 0.00
I
S
124
I 0.00
I
S
125
I 0.00
l
S
126
I 0.00
I
R
127
I 0.00
I
NA
Mougne x TVU 11.85
12%
1 0.00
I
R
129
I 8.33
l
R
130
110.53
I
R
131
1
6.25;
I
R
132
I 0.00
i
R
133
I 0.00
I
R
Notes :
R, Résistant
S, Susceptible
NA- R&act:ion not available
In the field observations 101 entries were observed to be free
from virus infection. Al1 the entries of the crosses 59-9 x B21(12),
.58-57 x TW 1185 (5) and C;asa 16 x CB5 (15) did not show virus infection.
However , the screen house reactions were partially confirming the field
observations. In the screen house test 65 entries showed resistant reac-
tion and 29 susceptible. In this test also no entry from the crosses
59-9 x B21 and 58-57 x ~~‘~1185 showed susceptible reaction. During 1986
screening at Dj ibelor , a11 the plants of the family 59-9 x B21 were also
observed to be free from virus. In a11 49 entries showed resistant reac-
tion in the screen house test as well as no virus incidence in the field.
From the material planted in the field, individual plant selections were
made based on virus resistance and other desirable characters.
An experiment with 42 individual plant selections made from
the above mentioned off season experiment together with 8 parents was laid
out during rainy season of 1987 at Djibelor for confirming the virus
resistance of these selections. The screening method
was the same that was used during 1986 season. One line of a local suscep-
tible variety (Spreader row) was planted after every two test entries for
multiplying the inoculum. The spreader rows were sown on 15.07.1987. The
test entries were sown on ll.and 12.08.87. By ‘this time the virus had
started appearing on the spreader rows. The test entries were inoculated
on 26.08.87 and 27.08.87 with the sap from the infected leaves,@arborundum
powder was added to the inoculum to act as an abrasive. The inoculation
was done by rubbing the fully grown well expanded primary leaves with a
forefinger wetted with the inoculum.
The virus symptoms on the test entries had started appearing
in the first week (of september. However,at the time of first observation
which was taken on 8.09.87 the incidence was almost neglegible. The second
observation was recorded on 25.09.87 which revealed 5 entries .L:ving
virus infection while the rest were still free of virus. In the final
observations which were recorded on 23.10.87, 13 entries showed virus in-
fection. The results of the final observations are summarised in table 2.
Table 2 : Virus incidence in the field at Djibelor
on selected material of F4 generation.
.
--
-
Cross & Entry na
Virus
Other
Virus
Other
incidence %
Diseases
Cross & Entry
incidence %
diseases
(AV of2 rep)
noticed
No
(AV of 2 rep)
noticed
--.
Dlougne x (MougnexIT 810 1032)
Casa 3 x B 21
4-2
5.88
26
3
0.00
l-l
3.85
27
15 -1
0.00
l-4
0.00 -
WB
2 8
15 -1
0.00
WB
2-1
0.00
2 9
2 0
0.00
WB
2-3
0.00
30
23
0.00
WB
3-l
10.72
31
29 -1
0.00
3-3
0.00
32
29 -1
0.00
5-2
2.94
3 3
3 3
0.00
59.9 x B21
6-l
0.00
34
6
0.00
58-57 x TW 1185
8-2
0.00
WB
3 5
1 y1
0.00
13-2
0.00
WB
36
1 -1
0.00
13-4
0.00
WB
37
4 -1
5.00
WB
:14-1
0.00
38
4 -1
4.55
WB
15-6
5.88
3 9
4 -1
1.00
18-6
0.00
4 0
4 -1
0.00
Casa 16 x CB5
1 6
12-l
4.76
41
5-l
0.00
17
12-2
o.oc
WB
42
?Y2
2.63
Parents
7-l
0.00
43
Mougne
0.00
7-2
0.00
4 4
58 -57
5.88
8
0.00
4 5
m -81~1032 0.00
14
0.00
NB
4 6
Casa 16
0.00
WB
Casa 16 x B21
?2
6
0.00
4 7
CB 5
0.00
0’3
-.
10
0.00
48
TV’JJI 185
o,oo
Casa 16 X(B21x1137)
24
1
0.00
49
Casa 3
6.25
25
2
0.00
50
59-9
26.72
Yot e : WB = WEB BLIGHT
8
From the results in table 2 it is seen that 5 parents viz ;
Mougne, Casa 16, CB5, IT 81D 1032 and TWJ 1185 are resistant while 58-57,
Casa 3 and 59-9 are susceptible. Reactions of Casa 16 and 59-9 were con-
tradictory to the reactions obtained last year. In the screen house test
conducted during Xov.86GJan.87 Casa 16 showed susceptible reaction while
59-9 was free of virus. Mougne and CB5 which are free of virus in this -tes.; were
obser;rnd .tc, be susceptible on farmers’ fields during last year.
Another set of 38 entries were also screened alongwith the ex-
neriment described on the previous page. This set consisted of 30 entries
from the cross B 21 x TVX3236,4 entries from the cross 58-57 x IT 81D1137
(which were found resistant during 1986 screenirg)and
4 parents. The
screeningmethod was the same that was followed for the previous experiment..
The sowing was done on 11.08.87 and the inoculation on 26.08.87. At the
time of first observation on 8.09.87 ; 2 entries
and 1 parent (58-57)
showed virus infection. The subsequent observations were noted on 25.09.87
and 23.10.87. The results of the final observations are presented in
table 3.
9
Table 3 : Virus incidence in the field at Djibelor on advance generation
-
-
e
-
m
-
. -
material..-
Cross & Entry No
IViruslOther 1 Cross & Entry No
IVirus 1 Other
Inci- Diseg-
I
I
I
Inci-
I
I Diseases
dence ses No-
dence$ Noticed
l%(~v.iticed 1
I (AV of I
of 21
2 Rep)
.Rep )
-
-
,-
B21 x TVX. 3236
B21 x TJX. 3236
1
’
ISB6
60~
0.00 WB,ASB 24
Ts86
84~
0.00
a.
..: CI
:.(l
2
1s,B6
62~
0.. 00
25
1.~86 85N
0.00
3
IS86
63N
0.00 WB
26
1$'84
86~
0.00
4
IS36
64~
0.00
27
1s 86 87N
0.00
5
1s 86
65N
0.00.
2 8
Is86
88~
0.00
WB
6
IS 36
66~
0.00
29
1s 86 89N
0.00
7
IS86
67N
0.00
3 0
Is86
9ON
0.00
8
IS 36
68~
0.00 WB
31
Bambey 21
0.00
.:::.:.;*
9
1s 86
69N
0.00
3 2
TVX 3236
0.00
10
1s 86
70N
0.00
58-57 x IT81D1137
I
3 3
1~~86
282 N
0.68
11
rs 86
71N
0.00 WB
3 4
E-36
299N
0.00
W B
12
IS.86
72N
0.00
3 5
IS‘86
240N
25.24 WB
13
1s 86
73N
0.00 ASB
3 6
IS;86
253N
0.00
WB
14
1s 86
74N
0.00
3 7
58-57
24.27
WB
15
1s 86
7515
0.00
38
I'r 81~ 1137
0.00
16
SS86
76N
0.00
17
1s 86
77N
0.00 WB
18
ISa86
78N
0.00
Note :
19
. IS86
79N
0.00
WB = WEB BLIGHT
2 0
IS86
80~
0.00 WB
2 1
X86
81~
0.00 WB
ASB = ASHY STEI'4 BLIGHT
2 2
13886
82~
0 . '00
2 3
1s 86
83N
0.100 WB
10
The results in table 3 revealed that a11 the 34 entries from
the cross B21 x TVX 3236 and 2 entries (IS86 299N and IS',86 253N) from
the cross 58-57 E: IT81D 1137 were resistant.IS86 282~, another entry
from the same cross showed neglegible infection (0.68%). Out of 4 parents,
3 were free from virus vi2 ; 321, TVX 3236 and IT81 D 1137. 58-57 showed
the highest virus infection (24%).
A third set of 32 entries comprising of 17 breeding lines of
our program and 15 IITA entries received from%FGRL\\D were screened in
the same manner as done in the previous experiments. The sowing was done
on 12.08.87 and inoculation on 27.08.87. However, the disease develop-
ment was poor in this tria1 which was evident from the poor infection on
the spreader rows,All the test entries were free from virus.
A set of 5 varieties were also grown in the same field alongwith
the above screening trials. Though these varieties were not artificially
inoculated, some of them showed a very high incidence of virus infection,
B21 and TVX 3236 were free of virus while amongst the susceptibles inclu-
ded Casa 3 (25%), 58-57 (60%) and 59-9 (83%).
. . . :
:.. :.
11
42 entries comprising of 38 breeding lines from advance trials
and 4 check varieties were screened in the screeen house during Sept-Oct
1987. About 6 seeds of each entry were sown in separate pots. The inocu-
lation was done on 26.09.87 and repeated on 28.09.87. The inoculum was
prepared from the infected leaves of 58-57 collected from Bambey. The
methods of preparing inoculum and inoculation were the same as used pre-
viously and doscribed in the beginning of the report. The symptoms started
appearing in the first week of october. The reactions noted on 17.10.87
are presented in table 4.
Tablee 4 : Screen house reactions of entries from Advance Trials
Entry
Reac tion
Entry
Reaction
In,.Tr
235 N
R
IS86
2NN
R
-“_
245 N
S
1'
- -
76 N
R
-“_
247 N
R
1‘
- -
93 N
R
-“_
252 N
R
-"_
114 N
S
- “_
269 N
R
- "_
168 N
R
- ” -
276 N
R
1,
- -
185 N
S
_“_
283 N
R
-f’-
217 N
R
-“_
292 N
R
-“_
224 N
R
.
VI
- “_
309 N
S
- -
237 N
R
- “_
310 N
R
-)‘-
241 N
R
- “_
239 N
R
-“_
253 N
R
-“_
259 N
S
- ” -
174 N
R
-“_
279 N
R
-1’ -
191 N
S
-“_
286 N
R
-“_
218 N
R
-“_
299 N
R
-II-
219 N
S
-“_
36 N
R
-“_
248 N
R
- “_
48 N
S
-1’ -
2'75 N
R
-“W
63 N
R
58-57
S
- ‘1-
121 N
R
TVX 32 36
R
B”_
140 N
R
Mougne
R
- “_
170 N
S
B 21
R
Notes : R = Resis.tant
S = Susceptible
12
The results indicated that quite a large number of entries did not show
virus infection. Out of 38 breeding lines 29 were resistant and 9 suscep-
tible. Amongst the check varieties 58-57 showed susceptible reaction while
TVX 3236, Mougne and B21 were free of virus infection.
During the subsequent observation taken on 27.10.87 entry n’EF36
23935 was found susceptible,All other reactions remained the same.
13
1.2. Multiple disease screening nursery
Screen:ing the germplasm varietizagainst principle cowpea di-
seases was continued at Bambey during this year also. In a11 243 germplasm
varieties comprising of mostly local collections and few varieties ob-
tained from International Institute of Tropical Agriculture,Ibadan
(Ni-
*
geria) were screened against major diseases such as bacterial blight,
virus, choanephora pod rot, web blight, ashy stem blight and cercospora
leaf spots. The disease nursery consisted of spreader rows,indicator rows
and the test entries. Two varieties were used for spreader and indicator
rows viz. Bambey 21 (bacterial blight susceptible) and 58-57 (virus sus-
ceptible).Half line was sown to B 21 and the remaining half to 58-57. One
line of these susceptible varieties was sown on 20.07.87 as spreader row
every after 4 test entries. Thz sowing of test entries was done on 28.07.87.
One line of indicator rows was sown on the same day every after 2 test
entries. One line of L1.5 m length was sown to each test entry. The spacing
between 2 lines was 80 cm while between 2 plants was 50 cm. Thus there
were 10 pockets in each line of which 5 were sown to B 21 and 5 to 58-57
“.: . .
in case of spreader and indicator rows. Each test entry was repeated twice.
A border of 4-6 lines of B 21 and 58-57 was sown a11 around the experimen-
ta1 plot. A suspension prepared from bacterial blight infected leaves
of 1986 rainy season was sprayed on the experimental plot on 27.08.87,
58-57 plants in the spreader rows were inoculated with virus on 31.08.87.
The inoculum was prepared by blending the infected leaves collected from
seed multiplication plot of 58-57 at Bambey during 1987 rainy season in
a buffer solution of sodium and potassium phosphates.
The virus infection on the spreader rows was satisfactory.
However , it did not spread to test entries,Cnly six test entries developed
virus infection. Similarly bacterial blight incidence was also very low.
Only 17 entries showed bacterial blight infection. This may be due to
very high natural infection of web blight and ashy stem blight in the
disease nursery plot which night have suppressed the bacterial blight and
virus infections. Incidence of choanephora pod rot was also low. The cer-
cospora leaf spot infection developed at late stage and was seen ~,ostly
on late entries. The observations on a11 the diseases are summarised in
t a b l e 5.
14
Table 5 : Summary of results on infection of major diseases
(Average of 2 replications)
_ .
--
I
. ;. \\’ INP I
W B
1 ASB 1 VR 1 BB
l
C R
I
CPR
Ch-N' 1
- -
I
l INC ' INT ' INC ' INC ' INC ' INT ' INC ' INT ' INC ' INT
1
58-57
1 0
0
0
0
11
0
0
0
0
0
0
2
58-39
2 2
1 0
3.0
0
0
1 0
3
0
0
0
0
3
58-24
9
100
100
5 0
0
2 5
7
0
0
0
0
4
59-12
32
17
1.7
9
0
0
0
8
2
0
0
'5
~9-1-12-12
18
3 8
1.6
9
0
9
2
0
0
0
0
6
78-45
1 2
5 0
2
0
0
0
0
0
0
0
0
7
Jan Haoussa
7
55
52
0
0
0
0
0
0
0
0
8
66-71
3 2
3 4
34
34
0
0
0
0
0
0
0
9
58-161
1 4
2 0
315
2 0
0
0
0
0
0
0
0
10
60-2
29
12
311
9
0
0
0
0
0
0
0
II.1
78-1
17
6 4
60
59
0
0
0
0
0
0
0
12
58-152
7
6 2
3 9
3 6
0
0
0
0
0
7
1.5
'13
78-44
29
35
30
2 5
0
0
0
0
0
0
0
'14
59-32
2 9
5 0
50
5 0
0
0
0
0
0
0
0
'15
84 E-l-lot
3 0
4 0
1+0
4 0
0
9
‘1
0
0
0
0
s.6
CT 81~1032
1
0
0
0
0
0
0
0
0
0
0
17
59- '2.9
2 1
32
30
18
0
0
0
0
0
0
0
18
58-185
2 4
2 2
2 2
0
0
0
0
0
0
0
0
19
Cvu 69
1 6
60
3 4
2 5
0
0
0
0
0
0
0
20
78-7
11
13
:t3
0
0
0
0
0
0
0
0
21
66-68
7
17
8
0
0
l7
4
17
4
0
0
22
POP 735
14
7 5
6 7
6 5
0
0
0
0
0
0
0
>'
9L _3
CB 5
1 2
5 0
'+3
5 0
0
15
4
0
0
0
0
,24
'(3 B24
13
9 2
92
7 5
0
0
0
0
0
0
0
r5
IT82D713
6 190
54
5 0
0
0
0
0
0
0
0
:36
78-9
14
7 3
7 3
7 3
0
0
0
0
0
0
0 *
2 7
casa 16
7
5 8
58
5 0
0
0
0
0
0
4
1
2 8
58-25
6
0
0
0
0
0
0
0
0
0
0
2 9
58-184
6
0
0
0
0
0
0
0
0
0
0
:jo
1
60-3
7
65
1+4
3 0
0
0
0
0
0
0
0
3 :1
18 31
11
ND0
7 5
5 0
0
0
0
0
0
0
0
'i'able 5 : Summary of results on infection of major diseases
(Aveïagc of 2 replications)
--I
-
-
-
-
Enih$
'
NP '
W B
1 ASB 1 VR 1
BB
I
CR
I
CPR
SrN"
I
I INC I IN'T I INC ' INC ' INC ' INT ' INC ' LNT '
INCJ--INT--
- - -
32
Ai 3
2 4
37
20
18
0
0
0
0
0
0
0
33
59-208
16
8 4
7 3
5 4
0
0
0
0
0
0
0
3 4
66-86
2 5
2 6
:t8
0
0
0
0
0
0
0
0
j 35
66-91
2 7
4
4
4
0
8
0
0
0
0
0
/ 34
58-79D,A,
15
2 0
:10
0
0
2 2
11
0
0
0
0
37
78-21
2 4
0
0
0
0
0
0
0
0
0
0
38
63-1
2 6
2 5
2 1
9
0
4
1
7
2
0
0
! 3'3
Pr '7
0
NA
NA
NA
N A
N A
NA
NA
N A
N A
NA
l-r0
8L-Z-ljL
2
0
0
0
0
0
0
0
0
0
0
I+l
66-37
1 6
2 4
:t3
0
0
1 9
2
0
0
0
0
42
81~2814-4
9
17
:17
17
0
17
4
0
0
0
0
43
82-7PRIMA
11
4 7
:34
2 2
0
0
0
0
0
0
0
44
14 ~25
16
8 8
!50
5 9
0
0
0
2 1
7
0
0
45
66-54
18
8 4
67
5 0
0
0
0
0
0
9
2
46
60-9
2 0
5 0
4 1
32
0
0
!O
0
0
0
0
47
78-35
18
4 5
28
1 0
0
1 0
3
0
0
0
0
:$8
AS-5
2 0
4 0
131
2 7
0
0
0
9
7
0
0
'49
AS-2
13
15
'15
15
0
0
0
0
0
0
0
50
58-43
2 3
0
0
0
0
0
0
6
2
4
1
51
67-30
19
5 0
!?O
5 0
0
0
0
6
2
0
0
52
63-33
12
0
0
0
0
0
0
2 5
5
0
0
53
66-l
2 8
71
'52
39
0
0
0
1 2
7
0
0
54
66-149
2 2
5 0
'50
0
0
0
0
9
6
0
0
55
58-80
16
7 6
'73
70
0
0
0
0
0
0
0
56
66-61
7
8 8
;88
8 8
0
0
0
0
0
0
0
57
58-79
19
3 5
.35
2 5
0
0
0
0
0
0
0
58
36-64
2 3
6
3
0
0
0
0
0
0
0
0
59
78-29
32
-,
0
0
0
0
0
0
0
0
0
0
6 0
68-24'
2 1
2 8
16
11
0
0
0
0
0
0
0
61
66-21
19
17
L7
17
0
0
0
2 5
7
C
0
42
TN88-63
2 3
6 6
!Y3
25
0
0
0
8
2
0
0
16
Table 5 : Summary of results 'on infection of major diseases
(Average of 2 replications)
-
-
!
'
!'y
INP I
W B
1 ASB 1 VR 1 BB
I
C R
I
CPR
I
I INC I INT I INC ' INC ' INC ' INT ' INC ' INT I INC I INT
.- . . ..-=
1 44
11
39
34
2 2
0
0
0
0
0
25
7
110 B 33
12
69
32
13
0
0
0
0
0
2 5
1 3
7847
23
1 0
1 0
1 0
0
5
2
8
2
0
0
XL64
2 4
29
9
0
0
4
1
0
0
13
3
16 ~27
8
0
0
0
0
0
0
0
0
0
0
66- 73
1 4
0
0
0
0
0
0
0
0
0
0
58-95
23
0
0
0
0
5
3
8
2
0
0
82-6
25
23
1 8
0
0
5
1
5
1
5
1
1 47
1 4
60
49
1 5
0
0
0
0
0
0
0
12 3 22
1 6
50
22
20
0
0
0
42
11
0
0
58-37
20
22
1 4
11
0
0
0
0
0
0
0
58-16~
29
29
27
2 2
0
0
0
0
0
0
0
58-146
3
100
100
100
0
0
0
0
0
0
0
66-58
28
69
62
40
0
0
.O
0
0
2 9
5
i
78-25
1 7
76
72
50
0
0
0
0
0
0
0
66-74
15
55
36
10
0
0
0
0
0
0
0
13 21
2
100
100
100
0
50
15
0
0
0
0
60-6
6
0
0
0
0
0
0
0
0
25
6
A S 6
25
17
11
0
0
0
0
0
0
0
0
81D 83~
1 6
34
25
0
0
0
0
0
0
0
0
AS 9
1 6
1 4
9
0
0
0
0
0
0
0
0
85 F 962-4 27
4
4
0
0
0
0
0
0
4
1
78-23
28
25
1 3
0
0
0
0
0
0
0
0
59-24 Dl
28
58
55
1+0
0
0
0
0
0
0
0
66-14
29
3 1
28
cl7
0
0
0
0
0
4
1
58-153
22
1 8
11
9
0
0
0
0
0
1 3
3
60-l
23
38
34
27
0
0
0
0
0
13
3
83-D-328-4'-=
4
'1
0
0
0
0
0
0
0
0
1 94
3 1
54
4 1
30
0
0
0
0
0
0
0
58-74 Dlc,. 2 6
1 5
1 2
0
0
0
0
4
1
4
1
7
17
'!'able 5 : Summary of results on infection of ma or diseases
(Average of 2 replications)
.-
-ÏI Entry LJP I WB
1 ASB 1 VR 1 BB
I
C R
I
CPR
l
I
INC I INT I INC ' INC ' INC ' INT ' INC ' INT ' INCINT
-
__
58-181
6
100
100
88
0
0
0
0
0
0
0
i 59-25
20
90
88
80
0
0
0
0
0
0
0
58-154
25
50
4 3
40
0
0
0
0
0
0
0
58-30
22
91
8 0
42
0
0
0
0
0
0
0
58-74
35
2 2
1 6
7
0
0
0
0
0
0
0
Lç^ 16xBZlx
21
73
51
3 6
0
0
0
0
0
0
0
1137
POP 736
25
79
73
58
0
0
0
0
0
0
0
58-109
20
50
50
50
0
0
0
23
11
0
0
"1 -4.7
15
86
86
86
0
0
0
0
0
0
0
59-5
25
42
35
1 5
0
0
0
0
0
0
0
58-58
2
0
0
0
0
0
0
0
0
0
0
58-44
33
3
1
0
0
0
0
0
0
0
0
I 86~R7
1 4
17
13
9
0
0
0
0
0
0
0
58-191
27
23
1 8
1 4
0
0
0
5
1
cl
0
66-27
26
44
4 4
25
0
0
! 0
0
0
0
0
cgb12
19
43
34
22
0
0
0
0
0
0
0
66-51
2 0
40
38
35
0
0
0
0
0
0
0
58-161
26
29
29
25
0
0
0
0
0
0
0
66-38
2 2
45
42
11
0
0
0
0
0
0
0
ii2-2-13
0
N A
NA
NA
NA
NA
NA
NA
NA
NA
NA
58-155
13
88
67
88
0
0
0
0
0
0
0
58-81
23
16
16
8
0
0
0
0
0
0
0
Y’4 S 2246- 4
22
6 2
42
5 2
0
0
0
7
2
0
0
tx-53
13
37
37
29
0
0
0
0
0
0
0
78-46
24
0
0
0
0
0
0
0
0
0
0
58-32
35
27
2 4
19
0
0
0
0
0
0
0
58-185 Y
25
7
7
7
0
0
0
0
0
0
0
'ii 1 - .,5*7
15
22
2 2
? ?
0
0
0
0
0
0
0
58-162
32
36
29
2 1
0
0
0
0
0
0
0
78-6
2 0
0
0
0
0
0
0
0
0
0
0
Table 5 : Summary of results on infection of major diseases
(Average of 2 replications)
-
-
-
.r: tr-;;
'NP I
W B
1 ASB 1 VR 1 BB
I
C R
I
CPR
--
SrN ’
I
' INC I INT 1 INC ' INC ' INC ' INT ' INC ' INT ' INC ' INT
123 j TVX :32-36
1 4
0
0
0
0
0
0
0
0
0
0
i24 j '78-32
2 6
0
0
0
0
0
0
0
0
10
3
s25 1
9 -19
I 24
0
0
0
0
0
0
0
0
0
0
:126
58-47
1 0
1 0
1 0
10
0
0
0
0
0
0
0
:l 27
63-8
29
0
0
0
0
0
0
0
0
5
1
:128
66-56
28
0
0
0
0
0
0
0
0
9
3
:i 29
58-21
19
10
3
0
0
0
0
0
0
JO
0
:1 30
58-221
1 4
1 7
17
0
0
0
0
0
0
00
0
:1 31
66-46
24
12
8
1 2
0
0
0
0
0
0
0
‘132
58-79T
18
90
85
0
0
0
0
0
0
14
4
133
B 32 ID
1 4
57
50
54
0
0
0
0
0
0
0
134
59-95
21
90
8 6
61
0
0
0
0
0
0
0
1.35
VE 78-42
19.
‘67
66
69
0
0
0
0
0
“0
0
136
66-77
22
50
50
50
0
0
0
0
0
4
1
J 37
58-19
29
1 9
14
1 0
0
0
0
0
0
00
0
138
58-64
23
7
4
0
0
0
0
0
0
0
0
139
58-17
2 9
‘85
9’7
4.7
0
0
0
0
0
0
0
3.40
58-50
1 8
89
7 4
62
0
0
0
0
0
0
0
3. 41
58-60
19
1 3
13
0
0
0
0
2 2
7
0
0
142
78-42
1 6
ï.5
15
15
6
0
0
0
0
17
4
; 1.43
78-36
2
0
0
0
50
0
0
50
13
0
0
j 1.44
63-5
21
0
0
0
0
0
0
0
0
0
0
1 145
78-5’
1 3
0
0
0
0
0
0
0
0
0
0
/
j 1.16
66-39
1 8
88
78
75
0
0
0
0
0
0
0
l
; 2.47
59-20
26
1 7
17
0
0
0
0
0
0
11
3
j :.‘-18
’
66-67
23
29
29
1 5
0
0
0
0
0
0
0
i 149
82-9
9
0
0
0
0
0
0
0
0
l
J
0
0
/ 1.50
IAR-48
8
50
?lO
50
0
0
0
2 2
6
0
0
I1 151
58-16 Dl
100
00
72
0
0
0
0
0
0
JO
0
; 1.52
84 D" 371
30
J.6
1.6
0
0
0
0
0
0
0
0
153
58-15
2 4
53
50
3 1
0
0
0
0
0
00
0
19
Table 5 : Summary of results on infection of major diseases
(Average of 2 replications)
-
- *. ‘NP 1 WB
1 ASB 1 VR 1 BB
C R
I
CPR
%>No 1
I
' INC ' INT ' INC ' INC ' INC I INT
INC ' INT ' INC ' INT
-
I
- -
154
66-62
8
17
17
17
0
0
0
0
0
0
0
155
67-95
2 4
6 3
6 0
32
0
0
0
0
0
0
0
.156
58-52
21
72
5 7
2 8
0
0
0
0
0
0
0
'157
1 31
2'0
7
7
7
0
0
0
0
0
0
0
158
58-55
2 6
43
215
14
0
0
0
9
2
9
2
159
78-22
30
2 9
29
2 9
0
0
0
0
0
0
0
S60
78-39
2 4
31
3; 1
2 9
0
0
0
0
0
0
0
'161
66-52
2 8
9 7
9 5
6 8
0
0
0
0
0
0
0
i62
58-10'7
2 8
53
419
34
0
0
0
0
0
0
0
163
60-8
13
9 3
9 3
9 3
0
0
0
0
0
0
0
164
67-167
21
50
50
50
0
0
0
0
0
4
2
1.65
66-45
2 7
50
50
50
0
0
0
0
0
0
0
1.66
66- 89
13
8 6
8 4
7 9
0
0
0
0
0
0
0
16’7
59-30
2 8
7 5
6 9
4 8
0
0
0
0
0
'0
0
!
168
34s 2231-1
2 6
47
4 4
4 4
0
0
0
0
0
0
0
169
58-5
2 4
3 5
3 5
3 4
0
0
0
0
0
0
0
1.70
78-37
2 3
17
3.4
0
0
0
0
0
0
0
0
371
58-79D2B
24
s‘y
' '7p-
fo
0
0
0
0
0
0
0
172
66-12
2 5
7 4
6 5
5 8
0
0
0
0
0
0
0
1.73
78-26
2 7
50
50
50
0
0
0
0
0
0
0
174
58-185 D
2 8
50
4 6
3 5
0
0
0
0
0
0
0
175
58-12
2 4
4 0
3 5
30
0
0
0
0
0
0
0
376
66-59
17
43
217
2 2
0
0
0
0
0
0
0
177
67-166
18
39
32
34
0
0
0
0
0
0
0
178
58-74T
19
7 9
7 5
6 4
0
0
0
0
0
0
0
1.79
66-63
11
70
6 3
52
0
0
0
0
0
0
0
1.80
15
!r,
5
0
0
0
0
0
0
0
2-81
50
50
50
0
0
0
0
0
0
0
182
47
4 6
41
0
0
0
0
0
0
0
383
8 5
7 9
70
0
0
0
0
0
0
0
2 0
Table 5 : Summary of results on infection of major diseases
(Average of 2 replications)
!il.I’J
'NP '
W B
1 ASB 1 VR 1 BB
I
C R
I
CPR
I,
I INC I IN?-' I INC ' INC ' INC ' INT ' INC ' INT I INC I INT
-II - _ .--
1
184
78-2
2 1
29
22
29
0
0
0
0
185
67-32
3
00
00
00
0
0
0
0
186
59-26
2 4
69
61.
42
0
0
0
0
187
58-151
13
54
40
16
0
0
0
2
188
66-36
2 6
84
84
7 5
0
0
0
0
189
59-13
2 5
43
38
19
0
0
0
0
0
0
0
190
66-A4
3 0
22
13
00
0
0
0
0
0
0
0
191
78-10
30
0
0
0
0
0
0
0
0
0
0
192
66-17
18
0
0
0
0
0
0
7
;'
0
0
193
15 B 26
8
0
0
0
22
0
0
0
0
0
0
‘,;
194
66-22
3 0
32
32
32
7
0
0
16
4
0
0
195
Ndiambour
7
0
0
0
17
0
0
0
0
17
4
196
58-95 D2
2 5
0
0
0
0
0
0
0
0
0
0
197
82-10 ML
11
46
23
0
0
0
0
0
0
6
0
I
198
78-40
2 1
22
18
15
0
0
0
0
0
7
2
199
IT8iD1137
2'
0
0
0
0
0
0
0
0
0
0
200
66-76
15
0
0
0
0
0
0
0
0
0
0
201
58-40
9
48
3:;
2 5
0
0
0
40
20
0
1 0
202
'78-20
19
17
4
0
0
0
0
0
0
0
0
203
78-16
16
50
50
5 0
0
0
0
0
0
0
0
204
59-9-Dl
31
17
4
0
0
0
0
0
0
0
0
:
205
68-226
3 2
11
.3
0
0
0
0
0
0
0
0
206
78-26
35
0
0
0
0
0
0
0
0
10
2.5
2i!7
VLP Casa 16
28
4
4
4
0
0
0
0
0
0
0
208
58-28
22
7
7
7
0
0
0
0
0
0
0
209
TVIJ-662
23
55
4 2
43
0
0
0
0
0
0
0
210
S:i 328
4
25
13
0
0
0
0
0
0
0
0
<
211
182 VITAc>
27
0
0
0
0
0
0
0
0
10
1
212
'j8-74DlAR
18
20
20
2 0
0
0
0
0
0
8
2
213
78-8
19
22
2 2
2
0
0
0
0
0
5
2
214
58-2
16
15
9
7
0
0
0
0
0
0
0
21
Table 5 : Summary of results on infection of ma or diseases
(Average of 2 replications)
---
2 3.5
66-55
75
66
63
0
0
0
0
0
0
0
213
58-20
29
25
0
0
0
0
0
0
0
0
2 1'7
78-33
36
3 1
0
0
0
0
0
0
0
0
218
83-122
50
4 4
0
0
0
0
0
0
3 4
9
219
58-34
2
50
13
0
0
0
0
0
0
0
0
220
Mougne
1 0
40
3 5
0
0
0
0
0
0
0
0
2î 1
78-46
2 4
1 9
14
1 0
0
0
0
1 9
5
0
0
222
78-3
2 6
0
0
0
0
0
0
0
0
0
0
223
66 -40
2 2
0
0
0
0
0
0
0
0
0
0
224
fj9-24T
17
58
4 3
37
0
0
0
0
0
0
0 .
22'5
103-6
24
13
3
0
0
0
0
21
5
0
0
226
58-75
2 2
4 2
7.5
0
0
0
0
0
0
0
0
22.7
66-129
2 5
9 2
8 4
30
0
0
0
0
0
0
0
228
78-31
2 5
00
4 3
100
0
0
0
0
0
0
0
Lî9
78-24
2 4
50
14
45
0
0
0
12
3
0
0
2 -jo
67-159
1 7
00
9 2
66
0
0
0
0
0
0
0
22, 1
;~TVU 3629
3i
66
6 0
39
0
0
0
0
0
0
0
2 a :I>
., .-
IT 82D 716
8
“jq
4::
17
0
0
0
0
0
0
0
23 3
85F 898- 5 35
28
23
20
0
0
0
0
0
0
0
23
78-30
29
42
36
18
0
0
0
0
0
0
0
.’
23
66-48
24
19
1 9
16
0
0
0
0
0
0
0
2%
J
78-15
21
18
18
18
0
0
0
0
0
0
0
22, 7
58-42
1 2
38
38
3 8
0
0
0
0
0
0
0
2 3, S?
‘C 21
21
1 7
1 5
9
0
0
0
0
0
0
0
23
58-53
1 9
1 4
6
4
0
0
0
4
1
0
0
24.9
-r. 22
24
2 6
2 2
16
0
0
0
0
0
0
0
241
78-43
2 1
4 5
43
39
0
0
0
0
0
0
0
242
00
89
6 2
0
0
0
0
0
0
0
243
6 9
5 2
4 8
0
0
0
0
0
0
0
NOTE
WB -- Web blight ; ASB - Ashy stem blight
VR -- Virus
; Bit - Bacterial blight
CR -- Cercosporiose
,CPR-Choanephora
pod rot '
INC - Incidence : INT - Intentity
NA -- Data not available
NP -- Number of plants observed
2 2
From the results of table 5 it is seen that only 37 entries were
free from web blight infection while 204 entries were observed to be sus-
ceptible.
Seven entries including B 21 which was used in the spreader
rows exhibited 100% infection. This indicates the high level of disease
pressure in the nursery plot. Ashy stem blight infection was observed on
162 entries while 79 were free. The infection of this disease also was
very severe. Many B 21 plants in the
spreader and indicator rows were
completely killed by ashy stem blight. Due to very high pressure of both
web blight and ashy stem blight, the’
development of other diseases was
poor. Only 6 entries showed virus infection while 17 entries exhibited
bacterial blight infection. Infection of cercospora leaf spot appeared
late and was developed on 34 entries. Choanephora pod rot was also compa-
ratively poor and was seen on 31 entries only. In the whole nursery 23
entriegwere observed to be free
f’rom a11 diseases, However, 9 entries
had very poor plant stand (less than 10 plants). As such the final list
of the renaining14 varieties which did not show any disease infection is
a s under.
78-21, 78-29, 66-73, 78-46, 78-6, TV x 3236, 79-19, 63-5, 78-5, 78-10,
58-95 D2, 66-76,78-3 and 60-40.
1.3. Screening for bacterial blight resistance.
A set of 55 entries comprising of 51 breeding lines and four
parents were screened against bacterial blight in the screen house. Four
to five seeds of each entry were sown in each pot separately on 21.10.87.
The inoculation was carried out on 30.10.87 by the stem stab method des-
cribed in 1985 report. The observations for the bacterial blight score
were recorded on 20.11.8’7, u-12-.87 and 28.12.87 in 1 to 10 scale as
described in 1986 report. The results of this screening are presented in
table 6.
23
Table 6 :
-
-
Bacterial Wght reactionsof sonebreeding lines and pzents
in the screen house.
Entry
1 Score 1 Entry 1 Score 1 Entry 1
Score
1
Entry
1
Score 1
Entry
1
Score
,-'
Primary Tria1 1.
TVX3236 x B21 F6
1:s 8 7 313 N
1
1
1 314 N 1
1
1 315 N(
1
1 316 N 1
1 317 N 1
318 N
1
1
1 319 N 1
10
1 320 N13/10,1/4 1 323 N 1
1 324 N 1
325 N
1
NC
1 326 N 1
1
I327N(
3
1 328 N 1
1 329 N 1
I
l
I
I
I
I
I
I
I
B21 x IT 81D 1137 F5
I 332 NI 1
I 333 N I
I
334 N
1
1
330
335 N
I
I 1/6,2/1
1
I
I 331
336 N I!
1:
I
I
I
, 337 N 1
I
I
338 N
I
339 N
1 NG
340 N
I
11 341 N I3/lO,Y8'
342 N' 1
I 343 N I
I 344 I
N
I
I
I
1
345
I
I
N
1 1
I-
I
TVX 3236 x VCS 14 F6
434 -N
I
NG
I 435 N I NC
I
-1
I
I
I
I
TVX 3236 x TVU 1174 F6
350 N 1
1 1 351 N i
1 352 NI ‘1
1 353 N 1
1 354 N 1
1
355
,. :
N 1
NG I
I
I
I
I
I
I
I
:.; ::
Advance Tria1 II
Mougne x TVU 1174 F7
2NI
11
1
I
I
58-57 x TVU 1174 F6
185 N 1
1 1 168 NI 1
1 217 NI 1
1 22tiN 1
I
I
24
Advance Tria1 III
-
-
-
-
B 21 x TIJ~ 3236 ~6
63~
i
58 - 57 x TVY 1174 F 6
170 N 1
174 N
.-
1
191 N
NA
218 N ;
2l9N
7
58 - 57 x 1T81 D 1137 F 6
1586275 N
1
Parents
B 21
10
Mougne
1
58-57
1
TV x 3236
::
Note : NC = No germination
:.
NA = Reaction not available
The results in table 6 indicated that many breeding lines possess resistance
co bacterial blight. Out of 51 breeding lines, 34 remained free from bacterial blight
infection, 3 showed resistant reaction,l was moderately resistant,2 moderately susceptible,
1 susceptible, 2 highly suscep tible and 2 exhibitted heterogenous reaction. Amongst the va-
'Letles B 21 was 'Iighly susceptible while Mougne, 58-57 and TVX 3236 remained free.
25
II. Virus transmission studies
-
-
;::,:
.',..
4..
The literature shows that some of the viruses are transmitted
through seed. The common viruses prevailing in Senegal such as aphid-borne
mosafc virus andsoutherm bean mosaîc virus are reported to be perpetuated
through seed. Similarly there are reports indicating transmission of
virus by insects. Aphid-borne mosaîc virus is reported to be transmitted
by aphids? Anhis craccivora ,While beetlas Ootheca mutabilis are reported
to be responsible for transmission of southern bean mosalc virus. In
order to find out the extent of virus transmission through seed as well
as by insects some filler trials were conducted during 1987 trop season,
the results of which may help to determine the gravity of the problem
and to take suita'ble measures to check this transmission.
2.1. Transmission through seed.
This tria1 was conducted at Bambey on 58-57 variety;There were
two treatments. In the first treatment seeds collected from the virus
infected plants were used while the second treatment consisted of healthy
seeds collected from virus free plants.
Each treatment was sown in 5 x 2 m2 plot (4 lines of 5m lengh)
with a spacing of 50 x 50 cm2. Each treatment was repeated 4 times. The
sowing was done on 20.07.87,~he observations were recorded on 4.08.87
for the number of virus infected plants. Al1 the plots sown with healthy
seed did not show any virus infected plant, while the plots sown with
infected seeds showed 10 to 22% virus infected plants. The average was
17.5% which is quite high. This shows the seriousness of the problem and
emphasizeo :he need of hec,lthy seed production.
"
:
1.2 :
26
2.2.
Transmission by insects :
This tria1 was conducted attwo locations viz ; Bambey and Dji-
belor on 58-57-The tria1 consisted of two treatments : 1) Protection of
plants from insects using appropriate insecticide. 2) No protection.
Thimul 35 8OOg ai/ha was usad for protecting the plants against insects.
The incidence of aphids was noticed at Bambey which is a vector for aphid
borne mosalc virus. At Djibelor cowpea beetles were observed which serve
as vector for southern bean mosaîc virus.
The tria1 at Bambey was sown on 20.07.87.0.bservations
were
recorded twice in both protected and unprotected plots for virus incidence.
In the first observation noted at Bambeyy on 4.û8.87 it was revealed that
there was no virus in the protected plots while the unprotected plots
showed 9.64% virus incidence (Mean of 4 replications). There was conside-
rable increase in the virus incidence at the time of second observation
:,hich was taken on 25.09.87,unprotected
plots showed 20% virus incidence
(Average o f 4 replications ) Protected plots also showed 4.37% virus inci-
dence. This increase in the virus incidence indicated that the aphids
prevailing in the tria1 plot
were responsible for transmitting the virus
infection to the healthy plants. The virus incidence in the protected
plots may be because the insects had already transmitted the virus before
they were killed by the insecticide.Similar trend of results was noticed
at Djebelor also..The tria1 was sown on 12.08.87. First observation on
virus incidence was taken on 27.08.87 which. revealed very neglegible
infection in the unprotected plots. The protected plots did not show
any virus infection. The second observation which was taken on 25.09.87
revealed that the mean virus incidence in the protected plots was 16.5%
while it was 27.1% in unprotected plots.
The f’irst observation taken 2 weeks after sowing showed little
virus infection at both the locations which might have been transmitted
through seed.
27
But the subsequent increase observed in the second observation was c!ue to
transmissio?
of virus by vectoïs. The high incidence in the -,ocond observa-
tion indicates +hsY Insects -3.e.y an active role in the spread of virus.
III. Estimation of losses in yield due to major diseases.
3.1. Due to bacterial blight :
A filler tria1 was conducted at Bambey to estimate the probable
loss in yield caused due to bacterial blight.The :;rial was conducted on B 21
and consisted of two Vreaknents .l)plots with minimal disease infection by use
of healthy seed and 2)glots with maximum disease infection by use of infected
seed and inocl!latLon of -1ants. The sowing was dcne -on 23.07.87 in -5 ‘x 2m2
plot ( 4 lines,of 5n length ? f o r each t r e a t m e n t w i t h 4’ replfcations. .
The inoculation for maximising the disease infection was done on 27.08.87
by injecting the bacterial suspension in the leaves by infiltration tech-
nique. The observations were recorded for disease infection and the yield
data.
Thedisease intensity in the minimal disease infection treatment
.-
(uninoculated plots) ranged from 1.4’7 to 10.71 with an average of 5.61.
While the disease intensity in the maximum disease treatment (inoculated
plots) varied from 13.75 to 27.38 with an average of 21.22.
The yield data showed that there was reduction in yield in the
inoculated plots than the yield in uninoculated plots. The yield figures
in the inoculated :plots ranged from 3~18 to 565 Kg/ha with an average of
440 Kg/ha, while the yields of uninoculated plots were in between 490 to
912 with a mean of 713 Kg/ha. Thus there was 38.29% (273 Kg/ha) reduction
in yield due to more bacterial blight infection in the inoculated plots.
3.2. Due to virus.
Another Piller tria1 was conducted at Bambey and Djibelor to
estimate pro’bable loss in yield caused due to virus. The tria1 was conduc-
ted on 58-57 at both the locations.
28
There were two treatments 1)plots with minimal virus infection through
use of healthy seed and control of vectors and 2) plots with maximum virus
infection through use of infected seed and artificial inoculation of plants.
The Bambey tria1 was sown 20.07.87 in 5 x 2m2 plot for each
treatment replicated 4 times. The inoculation for maximising the virus
infection was done on 31.08.87 with the sap collected from the infected
plants. Same inoculation method as described in 1.1 was adopted. Observa-
tions were recorded for virus incidence and the yield.
The final observation recorded on 25.09.87 showed 10% virus
incidence in the uninoculated plots while 38.75% in the inoculated plots.
The average yield obtained in uninoculated plots was 603 Kg/ha while ino-
culated plots gave average yield of 498 Kg/ha.Thus there was 17.41%
(105 Kg/ha) loss in yield due to more virus infection in the inoculated
plots.
The Djibelor tria1 also showed the similar trend of results.
The tria1 was sown on 12.08.87 with the same plot size and replications
as that of Bambey trial,Virus inoculation in the inoculated plots for
maximising infection was done on 27.08.87 with the sap collected from
infected leaves as per the procedure described in 1.i. Observations were
recorded for virus incidence and the yield.
Uninoculated plots showed 17.78% average virus incidence in the
final observation taken on 25.09.87 while the inoculated plots showed
38.13%. Very low yieelds were obtained in both the plots. However,the
trend was the same.
29
IV. Identification of seed microflora and their control :
Some of the pathogens on the seed cause seed rot or root rot
resulting in very poor stand of the trop. This is observed invariably in
B 21 variety. Hence studies were under taken to identify the pathogens
attacking seed which resulted in seed rot / root rot and their control.
Seeds of 3 varietes viz B 21, 58-57 and Mougne were used for
these studies. The seeds were treated with Granox (4g/Kg), Benomyl (lg/Kg),
and Thiram (2g/Kg). One set of untreated served as control,Seed.microflora
was detected by rolled towel method. Seeds were put on sets of three
blotter sheets previously moistened with water. The sheets were rolled
and kept at room temperature. The sheets were opened after 10 days and
the observations were recorded for seed rot and root rot/ seedling in-
fection. The microflora associated with seed rot and root rot/ seedling
infection was examined under the microscope. The results are presented
in table 7.
i
Table 7 : rieed rot and root rot in seed of 3
cowpea varieties.
Variety
Seed
seed .rqt
[Healthy
root
Organisms isolated
treatment
(ungerminatedjseed germi rot %
from seed rot/root rot
%
Inated %
B 21
Control
61
23
16
Macrophomina phaseolir
(=Rhizoctonià bataticc
la)
Fusar-ium equiseti,
Fusarium sp; Penicil-
lium sp, .RhizwF
.Er&.&. -SP' 1
?
çr ranox
16
84
0
?
Benomyl
2 4
7 6
0
Thiralm
35
50
15
Macrophomina phaseolir
5%~57
Control
11
%9
0
Penicillium .sp,colle-
t o t r i c u m
capsici, Curvu_laria si
a-nia- sp
,z:.. :
Granox
0
100
0
Benomyl
0
100
0
Thiram
0
100
0
Mougne
Control
5
72
23
Rhizopus $p,As~~gill:
Spmophomina
phaseoïina
Benomyl
5
93
2
Rhizopus sp,Macropho-
&.na phaseôlina,
Granox
0
100
0
ErXnia
Thiram
5
91
4
Fhizopus sp,Penicilli
sp, MacroPh&x
-
The results in table 7 indicate that B 21 was more prone to infection of fungi
causing seed rot/root rot than 58-57 and Mougne. In B 21 seed dressing with Granox
and Benomyl reduced these diseases more effectively than Thiram. In case of 5iJL57
a11 three fungicides showed equal efficacy probably due to the fact that this varie
seed was less infected, while in case of Mougne,Granox was most effective with no
seed or root rot followed by Benomyl.
V. Survey of cowpea Diseases :
-
-
During 1987 rainy season, natural infection of ashy stem
blight and web blight was very severe. Both the diseases were seen at
a11 the locations and in almost a11 the trials. On Farmers’ fields
also these two were the main diseases encountered. Inccdence of bacte-
rial blight and virus was as usual on B 21 and 58-57 respectively .
Incidence of bacterial blight was quite high on B 21 at Nioro.Choane- -
phora pod rot was minor. Cercosporiose was noticed mostly on midlate
and late varieties at the end of trop cycle. The striga incidence at
Kebemer was comparatively more,58-57, which is reported to b?
resistcnt,
was also found to be altacked by striga. Stationwise
report of various
diseases encountered in the experimental ,nlots at the research stations
as well as minikit triais on the farmers’ fields is furnished in table 8 .
).’
‘..
Table 8: Cowpea diseases encountered during 1987 rainy season
Research Stations :
Bambev
Ashy stem blight : - B 21, 58-57, CB 5, TVX 3236 and many breeding lines
Rhizoctoniose
: B 21, CB 5, 58-57 and some breeding lines
Virus :
: 58-57, Ndiambour
Bacterial blight: B 21, CB 5
Choanephora >od rot : B 21, CB 5, 58-57
Cercosporiose
: B 21, 58-57
..:<:
These diseases were also noticed on some of the germplasm entries
in the disease nursery (sec table 5 of this report).
Ndiémane :
Ashy stem blight : B 21, 58-57, TV x 3236,
Mougne and some breeding lines
Rhizoctoniose : B 21
Nioro
RhSzoctoniose : B 2 1
Bacterial Blight : B 21
Virus : 58-57
32
Djlbelor
Virus : 58-57 ; 59-9 ; Casa 3
Web blight & ashy stem blight was seen on some of the breeding
lines.
Thilmakha
Ashy stem blight : B 21 ; 58-57; TVX 3236
Mougne and some breeding lines
Rhizoctoniose
- B 21, Mougne, 58-57, TVX 3236 and some breeding lines
Cercosporiose - 5’8-57 and few late breeding lines
Choanephora pod rot : B 21, 58-57, Mougne and few breeding lines
Choanephora pod rot incidence at Thilmakha was comparatively more
than Bambey.
Louga
Ashy stem blight n- B 21, CB 5, 58-57, TVX 3236
Rhizoctoniose-B 21, CB 5
Virus - 58-57
Bacterial blight-13 21, CB 5
Minikits
Sam Thialle
B 2 1 - bacterial blight, ashy stem blight, web blight, choanephora pod rot
Mougne - Ashy stem blight, web blight,choanephora pod rot, cercosporiose
58-57 - Virus,Cercosporiose,choanephora pod rot, web blight, ashy stem blighs.
TVX 3236 - choanephora pod rot, web blight, ashy stem blight
Sagatta :
B 21 - Rhizoctoniose, bacterial blight, ashy stem blight
GB 5 - bacterial blight, Rhizoctoniose
58-57 - Virus,cercosporiose
Ndiambour-choanephora pod rot
Thilmakha
B 21 - Bacterial blight, web blight, ashy stem blight, choanephora pod rot
TVX 3236 - Ashy stem blight, web blight
58-57 - Virus, cercosporiose, web blight, ashy stem blight,choanephora pod rot
33
Piougne- Web blight, ashy stem blight, cercosporiose, choanephora pod rot.
Xcur 3oumi
GB 5 - Rhizoctoniose, bacterial blight, ashy
stem blight
B 21 - Bacterial blight, Rhizoctoniose, ashy stem blight
58-57 - Virus, cercosporiose, ashy stemblight
Ndiambour - Ashy stem blight
Ngatt
58-57 - Cercosporiose, virus, web blight
B 21 - Bacterial blight, web blight, ashy stem blight, choanephora
pod rot
Mougne - web blight,cercospriose, ashy stem blight, choanephora
pnd rot
Mougne - web blight, cercosporiose,ashy stem blight, choanephora
pod rot
TVX 3236 - web blight, ashy stem blight, cercosporiose
Ndatt Fall
B 21 - Rhizoctoniose, ashy stem blightcbacterial blight
CE 5 - Web blight, ashy stem blight, bacterial blight
58-57 - Virus, cercosporiose
Ndiambour - Rhizoctoniose
Keur galo
58-57 - Virus, cercosporiose, ashy stem blight
T V : ! 3236 - Web blight, ashy stem blight
B 21 - Bacterial bl.ight, web blight, ashy stem blight
Mougne - Ashy stem blight.
34
I;I. Seed Production
-
During 1987 rainy season, seed multiplication plots of different
varieties were inspected periodical1y.B 21 and CB 5 plots were observed to
b e
infected by Rhizoctoniose while 58-57 plot showed some virus infected
.-
plants. In a11 the plots the virus as well as rhizoctoniose infectedplants
were removed to o'btain disease free seed.