Wanyera R.1,P.Njau1,S.Bhavani2,K.Nazari3 1 Kenya Agricultural Research Institute, Njoro 2 International Maize and Wheat Improvement Center( CIMMTY), Nairobi, Kenya 3 International Center For Agricultural Research in Dry Areas( ICARDA), Allepo, Syria

1. YELLOW RUST STATUS IN WHEAT IN KENYA
International Wheat Stripe Rust Symposium
18-20 April, ICARDA
Allepo, Syria
Wanyera R.1,P.Njau1,S.Bhavani2,K.Nazari3
1 Kenya Agricultural Research Institute, Njoro
2 International Maize and Wheat Improvement Center( CIMMTY), Nairobi, Kenya
3 International Center For Agricultural Research in Dry Areas( ICARDA), Allepo, Syria

2. IMPORTANCE OF WHEAT KENYA
 Wheat is 2nd most important cereal to maize
Wheat crop grows in wide range of altitudes
1800 - over 2700 MASL
Maturity is between 90-145 days depending
Location
Cultivar
 Only bread wheat is cultivated
 Current area - 150,000 ha/year
 20% of large scale farmers produce 80%
 80% of small scale farmers produce 20%
 Annual production 313-397 MT
 Demand /requirement -900,000MT/year
 Import >60%

3. IMPORTANCE OF WHEAT KENYA
Rising demand is due to:
 High population growth
 Changing eating habits
 Increased urbanization
 Also enhanced by exports of wheat products to the neighbouring
countries
 East Africa Community (EAC)
 Common Market for Eastern and South Africa ( COMESA)

4. IMPORTANCE OF WHEAT IN KENYA
Production has been steadily increasing over the last 20 years
• From an average of 1.9t/ha-2.5t/ha
• Improved( superior) varieties
• Movement to the non-traditional wheat growing areas

5. CHALLENGES
 Reappearance of a more virulent stem rust race (Ug99)
 Other biotic and abiotic factors:
 Yellow (stripe ) rust**
 Leaf (brown) rust
 Septoria spp
 Loose smut
 Fusarium spp
 Spot bloch among others
 Barley Yellow Dwarf Virus
 Cereal aphids ( e.g. Russian Wheat Aphid (RWA)
 Acid soils
 Climate change (drought & etc)
 High cost of inputs

6. CHALLENGES
 The wheat crop is attacked by a number of fungal diseases in
Kenya and the major and most important are rusts:

7. YELLOW(STRIPE) RUST
 Yellow rust attacked wheat as early as 1908
 Major threat a very year and no commercial variety is resistant
 Disease severity increases with altitude
 Serious epidemics also occur in lower altitudes (1800 masl)
 In the past resistance became ineffective in less than six
years, but now
 newly introduced resistant varieties loose resistance within
a short time
 Now even latest releases have succumbed to Yr infection
(e.g NjoroBWII) among others

8. COMMERCIAL VARIETIES
Variety Parentage and Pedigree Year of
release
Njoro BWII CM8181-12y-06PZ-4y-5m-0y-2AL-0AL-0M 2001
Njoro BWII Mutant 2001
Chozi F1271/CoC//Gen.CM76689-3y-08m-02y-4B-2y-0B- 1999
Kenya Heroe Mbuni/SRPC64//YRPC1 1999
K.Yombi Mbuni/SRPC64//YRPC5 1999
Mbega Fink “S” 1993
Duma R674-AV/UP301//GLL/SX/3/PEW ‟S‟/4/MAI ”S”//PEW „S‟- 1993
CM67245
Ngamia SW53=Buck Buck”S”CM31678 1993
K.Chiriku KTB/Carpintero “S” 1989
Kwale Kinglet,Cm33089-W 1987
Mbuni Za75/Ld357E-T3x Gu,x30520-IB-IB-3Y-0Y 1987
K. Kulungu On/Tr.207/3/CNO//SON64/4/6648-2- 1982

9. COMMERCIAL VARIETIES
Variety Parentage &Pedigree Year of
release
K. Kongoni C18154/2*Fr/2/*Romm/3/WIS.245-II-50-17/C8154/2/2*Fr 1981
K. Nyangumi R23/AFM//K6877=TZPP//SK6 1979
E/LR64HDM/3/AFM/4/KWS/K6661-53
K. Paka Wis.245/II-50-17//C18154/2*Fr/3/2*Tob.66 1977
K.Fahari Cross.6582xTobari66=TOBARI 66/SRPC527//eI8154/3/2 1977
K6661-53
K.Tembo Wis.245/II-50-17//CI8154/2*Fr/3/2*Tob.66 1975

10. OLD WHEAT VARIETIES
Variety Pedigree Year of
release
K. Kudu K131XK184.P.2A.I.F-K.7.K.2 1966
K.Leopard (lagxK354P3)X(C.1.12632X354.P3)- 1966
A.2.A.1
Trophy T-K2XY50-V1-42-17h-1r-1m 1968

11. EVALUATION OF YELLOW RUST ON COMMERCIAL VARIETIES
36 39 42
 16-18 commercial wheat SUDAN
ETHIOPIA
varieties evaluated in 8 sites Lake
Turukana
3 3
( 5yrs)
UGANDA
 Design RCB in 3 replicates
ENDEBBES
SOMALIA
ELDORET TIMAU
0 0
 Plot size 1.5x6m (8 rows) MOLO NJORO Mount
Kenya
Lake LANET
Victoria MAU-NAROK
NAIVASHA
NAIROBI
 Disease score taken twice (
modified Cobb scale
3 TANZANIA 3
Indian
Ocean
0 100 200 km Mombasa
0 100 200 ml
36 39 42

12. SUSCEPTIBILITY OF COMMERCIAL VARIETIES TO YELLOW RUST IN SELECTED SITES
Variety Year of 2002 2001 2002 2004
release
Timau MauNarok Timau MauNar Endebess MauNar Njoro Molo MauNaro
ok ok k
Njoro BWII 2001 - - - - - 40M 50S 20S 0
NjoroBWI 2001 - - - - - 40MR 90S 60M 30S
S
Chozi 1999 0 80MS 40MS 60S 40R 40S 70S 50S 50S
Kenya 1999 0 TR TMS 30MS 30R 5MR 40S 10S 70S
Heroe
K.Yombi 1999 - - TMS TS 30R 30MS 30MS 40S 0
Duma 1993 1 60S TR 60S 10R 30M 90S 50S 30S
Mbega 1993 30S 80S 60MS 60MR 5MS 15S 50S 20S 30S
Ngamia 1993 0 60MS 70MS 60MS 30R 60S 70S 50S 50S
Pasa 1989 0 60MS 20M 50S 40MR 20S 60S 30S 30S
K.Chiriku 1989 20S 85S TS 50S 30R 30M 40S 70S 60S
Kwale 1987 0 60MS 30MS 70S 40MR 10S 20MR 60S 20S
1Mt. Kenya Region 3North Rift
2Central Rift

13. SUSCEPTIBILITY OF COMMERCIAL VARIETIES TO YELLOW RUST IN SELECTED SITES
Variety Year of 2002 2001 2002 2004
release
1Tima 2MauNar 1Tima 2MauNar 3Endebes 2MauNaro 2Njoro 2Molo 2MauNar
u ok u ok s k ok
Mbuni 1987 20MS 30MS TMR 60S 30R 70S 40S 60S 20S
K.Popo 1982 0 25MR TMR 40S 30R 20S 70S 50S 40S
K.Kongoni 1981 30MS - 10M 50S 50S 20MR 60S 50S 20S
K.Nyangumi 1979 40S 50MS - 60S 30R 40S 40S 60S 20S
K.Paka 1977 10MS 90S 60MS 50S 40MR 30M 0 20S 60S
K.Fahari 1977 30MS 60MSS - 40S 30R 40M 80S 60S 40S
K.Tembo 1975 15MS 60MS 5M 40S 30R 20S 40S 40S 30S
1 Mt. Kenya Region
2 Central Rift
3 North Rift

15. SURVEYS
Survey areas:
 South Rift (Narok)
 North Rift (Uasin-Gishu,Elgeyo Marakwet,Trans-Nzioa, Mt.Elgon)
 Central Rift ( Nakuru, Naivasha, Njoro, Rongai, Bahati)
 Mt. Kenya region ( Laikipia, Nyahururu, Meru)
• Farms were picked at random stopping at 3-5 km or
nearest farm in sparsely distributed areas
Survey Form is used to record
GPS readings on:
Way point
Elevation
Latitude
Longitude
Growth stage of the crop
Disease severity (modified Cobb scale)
among others

17. OCCURRENCE OF YELLOW RUST IN COMMERCIAL FIELDS
Year Region Site (s) No.of %Yr Yr severity
farms infection
sampled
2007 South Rift Narok 75 4 TR-30S
2008 South Rift Narok 65 17 0-75S
2008 North Rift Uasin-Gishu,Elgeyo 99 26.6 0-100S
Marakwet,Trans-
Nzioa, Mt.Elgon
Central Nakuru, Naivasha, 59 3.5 0-20S
Rift Njoro, Rongai, Bahati
Mt. Kenya Laikipia, Nyahururu, 70 10.0 0-80S
Meru
2009 South Rift Narok 131 7.6 0-80S
North Rift Uasin-Gishu,Elgeyo 88 21.6 0-80S
Marakwet,Trans-
Nzioa, Mt.Elgon

18. YELLOW RUST OCCURRENCE IN COMMERCIAL FIELDS
Year Region Site(s) No.of % infection Severity
farms
sampled
2010 South Rift Narok 101 11.0 0-60S
2010 Central Nakuru, 40 17.0 0-60S
Rift Naivasha
2010 North Rift Uasin- 82 10.9 0-50S
Gishu,Elgeyo
Marakwet,Tra
ns-Nzioa,
Mt.Elgon

19. TRAP NURSERY
 Disease Trap nursery comprising :
 3rd IYRTN ( 75 entries) was planted in Timau
(3079 MASL) March 2010)
 4th IYRTN ( 85 entries) Eldoret(2181 MASL), June 2010
 4th IYRTN ( 75 entries ( MauNarok(2806 MASL)
 Each entry was planted in double rows of 0.5M
 Disease notes taken twice (modified Cobb scale)

20. RESULTS -TRAP NURSERY
 Severe infection of yellow rust in the 3 sites:
 Minimum infection in Eldoret (60%)
 Maximum infection (100%) in both Timau and
MauNarok
 Results indicated the presence of virulence for:
 Yr1, Yr2, Yr6, Yr7, Yr25 and Yr27

21. TRAP NURSERY
Cultivar Yr Gene
Mau Narok( Eldoret(2181 Timau(3079
(2606masl) (masl) masl)
Super Kauz Yr9,Yr27,Yr18 30S 60M 100S
Pastor Attila Yr31+APR 5S 40M 100S
Morocco 100S 40S 100S
Attila CM85836-50Y-OM-OY-3M-0Y Yr27+? 0 40M 100S
Chines 166(w;Yr1) (W;Yr1) 100S 20S 100S
Lee ( S:Yr7) (S;Yr17) 20S 15MS 100S
Heines Kolben (S;Yr6+1) (S;Yr6+1) 5S 0 100S
Vilmorin 23 (W:Yr3a, 4a+other) (W;Yr3a,4a+other) 40S TR 100S
Moro(W:Yr10) (W;Yr10) 0 TR 100S
Strubes Dickopf( W:2-More?) (W;2-more?) 0 TR 100S
Suwon 92xOmar (W) (W) 0 TR 80S
Clement (W:Yr9+Yr2+?) (W;Yr9+Yr2+?) 60S 0 20S
Morocco 100S 30S 100S
Hybrid 46(W:Yr14) (W;Yr4) 5S 0 10S
Reinchersberg 42((W:Yr7+1) (W;Yr7+) 0 15MS 80S
Heine’s Peko (S;Yr6+1) (S;Yr6+?) 0 30S 100S
Nord Desprez (W;YrND) W;YrND) 0 5MS 10S

22. TRAP NURSERY
Cultivar Yr Gene
Mau-Narok Eldoret Timau
Compaire (S;Yr8) (S;Yr8) 0 0 5S
Castens V(W;Yr32) (W;Yr32) TR TR 80S
Spalding Prolific( W;YrSP) (W;YrSP) 100S 40M 100S
Heines VII(W;Yr2+?) (W;Yr2+?) 40S 0 100S
Federation 100S 30MS 100S
Morroco 100S 30S 100S
Fed.4/Kavkaz(Yr9) Yr9 100S 30M 100S
Triticum spelta (Inter,Yr5) Yr5 10S 5S 15S
Kalyansona (s) Yr2 90S 30M 10M
TATARA CM85836-50Y-0M-0Y- 20S 40S 100S
2M-0Y-0PAK
Anza Yr A,Yr8 60S 30M 100S
Cham 1(DW) DW 100S 5R 100S
Cook (S) APR 60S TR 50S
Jupateco ‘R’(S) Yr18+ 100S 40S 10S
Jupateco ‘S’ 30S 60S 100S
Morocco 100S 30S 100S
Avocet S 40S 10R 100S

23. TRAP NURSERY
Cultivar Yr Gene
Mau-Narok Eldoret Timau
Avocet R YrA 60S 10R 10MS
Yr1/6/* Avocet S Yr1 30S 40S 100S
Yr5/6/* Avocet S Yr5 10S 5MR 70S
Yr6/6/* Avocet S Yr6 20S 15MR 100S
Yr7/6/* Avocet S Yr7 20S 10MR 100S
Yr8/6/* Avocet S Yr8 60S TR 100S
Yr9/6/* Avocet S Yr9 70S 5MR 100S
Yr10/6/* Avocet S Yr10 10S R 100S
Morroco 100S 30S 80S
Yr15/6/* Avocet S Yr15 0 R 5S
Yr17/6/* Avocet S Yr17 0 R 100S
Yr18/6/* Avocet S Yr18 0 15M 100S
Yr27/6* AOC Yr27 0 5M
AVOCET- Yr28 40S 15MR 80S
YRA*3/3/ALATAR84/AE.SQ//OPATA
CGSS00Y0024T-099M-20Y
Avocet-YRA83/PASTOR CGSS00Y00207T- Yr31 0 60M 40S
099M-1Y
YrSP/6*Avocet S YrSP 60S 50S 100S
YRCV/6*AOC Yr CV 60S 15MR 100S
Yr26 Yr Line R55 40S TR 40S

24. TRAP NURSERY
Cultivar Yr Gene
Mau-Narok Eldoret Timau
Morroco 100S 20S 80S
Yr24 Yr24 20S TR 90S
Yr26 Yr26 5S 5M 50S
Yr27 Yr27 60S TR 100S
YrSp Yrsp 5S TR 40S
Tre/6*AVS TR TR 100S
TP981 ? 15S -
TP1295 Yr25 25S -
Ciano 79 Yr27 20S -
Lai Bahadur/Pavon 1BL Yr27 15S -
Morrocco 20S -
Inia66 YrA 20S -
Lee Yr22,Yr23 15S -
Fieder Yr6,Yr20 50S -
Lemhi Yr21 25S -
Thatcher Yr7 20S -

25. CONCLUSION
 Results revealed severe infection of yellow
rust
 Yellow rust is on the increase in Kenya
 Strengthen race typing
 Joint
effort is required for resistance
breeding

26. THANK YOU