Transcript Slide 1

Identification of RYMV resistant
varieties in West Africa
Y. Séré, Africa Rice Center
A.A. Sy, M. Sié, R.G. Guéi, K.M. Miezan,
A. Onasanya, A. Afolabi,
S. Akator, M.M. Coulibaly, A. Hamadoun, A.Y. Sido, A.
Basso, E.M. Abo, S. Sara, F. Cissé
Africa Rice Congress
31 July – 4 August 2006, Dar es Salaam, Tanzania
OUTLINE
 Background
 Methodology
 Results
 Conclusion and way forward
Background
The early 90th RYMV spread in WA countries
• Hindered the efforts of intensification
• Reproduced Tungro scenario in Asia
Main causes (Ghesquiere et al., 2000):
• Development of irrigation
• Release of susceptible varieties from Asia
• Development of transplanting (Office du N)
Background
In Cote d’Ivoire (Nguessan et al., 1999, Yoboue et al., 2001)
• Yield losses from 20 to 60% reported
• Many farmers suffered complete crop failure
In Mali (Coulibaly et al, 2001; Hamadoun et al, 2001)
• Estimated losses: 187 millions CFA in O du N
• Selingue and inland Vallee arround Sikasso
region also highly infected
Background
In Niger (Reckauss and Adamou, 1986)
• Yield losses between 59 and 68 %
• Hot spots: Say1, Saga, Diomana, Bonfeba
Potential yield gap in the WA region for 19982000 = 329,000 metric tones of rice (Pinto, 2000)
Background
Varietal resistance is the main component of an
Integrate management of RYMV
ALTERNATE HOST
MANAGEMENT
CULTURAL
PRACTICES
VARIETAL RESISTANCE
VECTORS
MANAGEMENT
FERTILIZERS AND
SOIL CONDITIONER
INTEGRATED MANAGEMENT OF RYMV
Background
However resistance was found only within:
• African Oryza species (glaberrima,
longistaminata) and traditional African upland
rice varieties such as OS 6, LAC 23, and
Moroberekan (Singh and Paul, 1995)
• One indica Gigante (Tete) (Ndjiondjop, 1999)
None was suitable for intensive irrigated rice
production system
Background
Poor diversity of varieties used in West Africa (Séré
and Sy, 1994) :
• BG 90-2 (Mali), IR 1529-680-3 (Niger),
Bouake 18 (Cote d’Ivoire), ITA 212 (Nigeria)
and Jaya (Senegal) grown in 90 % of the
superficies
•They are all highly susceptible to RYMV
Background
Therefore is it possible while looking for a longterm solution from breeding programs,
to look for resistant/tolerant varieties
that yield at least as
the susceptible released ones?
Methodologies
1. Screening for RYMV resistance
Methodologies
First set = 222 varieties collected from
• IRRI (as IR 47686-15-1)
• NARS (for instance FKR 44, DJ 12-119)
• CIAT (CT 9153-11-7-1-1)
Second set japonica from
• IRRI (siter lines of IR 47686-15-1)
• USA (Norin, Litton, Leah) through INGER
Methodology
2. Yield trial for those that perform as well as
Moroberekan or Gigante (Tete)
ANOVA and mean comparison of yield
components and yield
Methodology
3. Special case of japonica: Yield trial under
different sowing densities
• 20 cm x 20 cm
• 20 cm x 10 cm
• Continuous line (8 g / m2)
• Normal transplanting
Methodology
4. On-farm test of the best candidate for
replacement in
• Niger
• Mali
• Côte d’Ivoire
• Guinea
On-farm test at Selingue (Mali)
Results
1. Identification of potential of candidates
 First set screened at Gagnoa in CI
Rank
RYMV
Varieties
1
3…
6…
8…
15
16…
149…
222
Gigante (Tete)
IR 47686-15-1-1
CT 9153-11-7-1-1
Moroberekan
PNA 647F4-56
CT 8248-1-12-1P-M-4P
Bouake 189
IR 60832-187-2-2-2
Yield
2.3
1.9
3.7
3.5
2.2
2.9
0.9
Results
Some of them were sent in Tanzania where the
following three were found resistant to RYMV
• H-232-44-1-1
• H-234-18-1-1-1
• GIGANTE (TETE)
Results
 first generation of japonica
Rank
RYMV
Varieties
1
2
3
4…
7…
9…
13…
70…
74
NORIN
LITTON
LEAH
LEMONT
IR 47686-15-1-1
Gigante (Tete)
Moroberekan
BG 90-2
Bouake 189
Results

Second generation of japonica:
Reaction of
IR 47686 sister lines
Variety (V)
Chlorosis
IR 47686-1-1-B
9.4 b
IR 47686-13-2-2
9.7 b
IRAT 104 (Parent)
11.8 b
GIGANTE
11.9 b
IR 47686-18-7-B
12.0 b
IR 47686-15-1-1
12.3 b
IR 47686-6-4-1-
13.5 b
IR 47686-9-1-B-
14.3 b
PALAWAN (Parent)
14.7 b
IR 47686-31-1-1
15.1 b
IR 47686-18-6-1
15.5 b
IR 47686-09-2-A
16.2 b
IR 47686-9-2-B
16.2 b
IR 47686-6-2-2
16.4 b
BOUAKE 189
45.6 a
Results
 Checking the performance of progenies
from a cross between Bouake 189 and
Gigante
Bouake 189
Gigante (Tete)
X
1
2
3
1
4
2
3
4
1 = Control
2 = Part of one leaf
3 = Entire one leaf
4 = The whole plant
1
2
3
4
Influence of inoculum pressure on a susceptible
and resistant varieties and one of their progeny
Results
2. Performance of selected candidates
 First set 16 var. in 6 localities in Côte d’Ivoire
Rank Varieties
Yield (kg/ha)
1 BG 90-2
2… CT 9153-11-7-1-
2256
5 IR 1529-680-3
6 BOUAKE 189
1933
7… PNA 647F4-56
1911
14… IR 47686-15-1-1
1108
16 H 234-18-1-1-1
900
2150
1922
Results
CT 9153-11-7-1-1 and PNA 647F4 are the best
candidate performing as Bouake and
 even more in some localities
 even in low RYMV pressure
Rank Varieties
Yield*
kg/ha
RYMV
**
Rank Varieties
Yield*
kg/ha
RYMV
**
…
..
2…
PNA 647F4-56
2667 b
1
3…
4
BOUAKE 189
2333 bc
1
6
CT 9153-11-7-1-
2200 bcd
3
7…
5…
At Duekue
* Mean of 4 replications
**RYMV score (1-9)
CT 9153-11-7-1-
1400 abc
3
PNA 647F4-56
1200 a-d
BOUAKE 189
1167 a-d
At Gagnoa
1
1
Results
IR 1529-680-3
IR 62161-22-1-2-1-1
IR 62161-22-1-2-1-1
Photo 5 : CT 9153-11-7-1-1 dans le bas-fond de Natio en Côte d’Ivoire
CT 9153-11-7-1-1 and PNA 647F4 showing some
tolerance to iron toxicity in CI
BG 90-2
Results
Same tendencies in 3 localities in Mali
Kayao in Office du Niger
Rank
1
Varieties
PNA 647F4-56
Yield*
6360 a
RYMV**
Rank
3
3
Varieties
Yield*
RYMV **
BG 90-2
3267 ab
5
PNA 647F4-56
3233 ab
3
2750 abc
3
1900
3
…
…
4
Selingue
BG 90-2
5680 abc
3
5
…
…
12
CT 9153-11-7-1-1
4927 abc
3
9
13
IR 47686-15-1-1
4753 bc
3
15
* Mean of 3 replications
**RYMV score (1-9)
CT 9153-11-7-1-1
IR 47686-15-1-1
c
Results
 first generation of japonica (15 entries)
Direct sowing at 20cmx10cm
spacing
VARIETIES
Yield*
kg/ha
CT 9153-11-7-1-1
5.2 a
IR 47686-15-1-1
4.8 ab
BOUAKE 189
Transplanting at 20cmx20cm
spacing
VARIETIES
Yield*
kg/ha
4.7 abc
CT 9153-11-7-1-1
4.5 ab
LEAH
4.0 bcd
BOUAKE 189
3.6 bcd
LITTON
3.8 bcd
LEAH
3.1
cde
LITTON
3.0
cde
IR 47686-15-1-1
2.7
Mean/treatment
(for 15 varieties)
3.3
Mean/treatment
(for 15 varieties)
de
2.6
Results
5
4
3
2
1
Bouake189
0
DS 20x20
DS 20x10
IR47686-15-1-1
DS C
Transplant
20x20
Effect of planting method and densities on the yield of two varieties
Results
 second generation of japonica
Varieties
kg/ha 1 Diff
IR47686-18-7-2
5286
994*
IR47686-9-2-B
5232
940*
IR47686-15-1-1
5072
780*
IRAT 104 (Parent)
4991
699ns
IR47686-09-2-A
4922
630ns
IR47686-6-4-1-1
4862
570ns
IR47686-13-2-2
4375
83ns
BOUAKE 189
4292
Control
PALAWAN (Parent)
4152
-140ns
IR47686-6-2-2-1
4081
-210ns
IR47686-18-6-1
3192
-1100**
1
= mean of 4 replications
** = significant at 1% level
* = significant at 5% level
ns = not significant
Results
2. On farm test of the performing candidates
 In Mali at Sélingué in 2004
Farmer 1
Farmer 2
RYMV
%
Kg/ha
RYMV
%
Kg/ha
CT 9153-11-7-1
18
3394
4
2264
PNA 647F4-56
0
2562
0
4262
IR 47686-15-1-1
0
930
0
1729
ADNY 11 (Control)
19
2062
1
3555
Varieties
PNA 647F4-56
PNA 647F4-56 was selected
by visiting farmers
Results
 In Mali at Niono (in 2005)
Varieties
Yield
(kg/ha)
RYMV
(1-9)
IR 47686-18-7-2
5080
1
BK X GG116
5000
1
PNA 647 F4-56
4800
3
BK X GG117
4600
1
IR 47686-9-2-A
4720
1
BG 90-2
4000
5
Visiting farmers chosen PNA647 F4-56 and BK x GG116
but:
BK x GG116 cycle appeared too long for double cropping
Results
 In Guinea at Seredou (in 2005)
Varieties
Farmer 1
Farmer 2
Yield
(kg/ha)
Yield
(kg/ha)
PNA647F4-56
1538
1475
BKxGGN°116
1416
1391
Adny 11
1313
1284
TCHO-TCHO (local check)
1247
1313
IR47686-9-2-B
1019
934
IR47686-18-7-2
1019
781
953
1031
BKxGGN°117
Conclusion and way forward
1.The best materials identified were:
 PNA 647F4-56 and CT 9153-11-7-1-1 (indica)
 IR 47686-15-1-1 and IR 47686-18-7-2 (japonica)
2. The highly resistance gene have been transferred
from Gigante into the susceptible Bouake 189
by WARDA providing another candidates
3. But some questions need clarifications for
long term solution:
Mainly when looking at disease progression
Bouake model
100
Disease severity (%)
90
80
70
60
50
40
30
20
PNA model
10
0
21
28
35
42
49
Days after infection
56
70
NERICA model
 Is such a reaction
• Adult plant resistance mechanism?
• Environment-dependant?
• Strain-dependant?
 What is its the genetic background?

The highly resistance gene found so far is it
the unique monogenic resistance to RYMV?
Thank to
DFID/CPP
Japan
IRRI & CIAT
Thank you
Merci
Asante sana
Obrigado
Melesi