Common bean is an important crop in Africa but yields are reduced by multiple fungal, bacterial, and viral diseases. The development of breeding parents with resistance to multiple diseases (MDR) could help manage this problem. CIAT-PABRA is utilizing molecular markers linked to resistance genes for diseases like anthracnose, Pythium root rot, and viruses, to pyramid these genes into common backgrounds. To date, some plants have been identified with resistance to 4 diseases, and others with resistance to anthracnose and Pythium root rot. These MDR parents will be made available to national programs to use in their breeding.

1. DEVELOPMENT OF MULTIPLE DISEASE RESISTANT
BREEDING PARENTS WITH THE AID DISEASE RESISTANT
DEVELOPMENT OF MULTIPLE OF MOLECULAR MARKERS
BREEDING PARENTS WITHA. Buruchara, A. MOLECULAR MARKERS
C.M. Mukankusi, R. THE AID OF Male, S. Sebuliba
C.M. Mukankusi, R. A. Buruchara, A. Male, S. Sebuliba currently being utilized for Multiple
Table 1. Molecular markers
Background: disease resistance breeding in PABRA
Table 1. Molecular markers currently being utilized for Multiple
Background: disease resistance Markers
Trait breeding in PABRA
Source
Common bean (Phaseolus vulgaris L.) plays an essential role in sustaining live-
lihoods of smallholder farmers and their families in Africa. At farm level, beans Trait Markers 709 Source 54 (Mahuku et al., 2004)
are attacked by aPhaseolus vulgaris L.) plays an essentialviral diseases leading to
Common bean ( combination of fungal, bacterial and role in sustaining live- ALS OPE4 MEX
poor yields (Fig. 1). The farmers and their families in Africa. At farm(MDR)beans
lihoods of smallholder deployment of multiple disease resistant level, varie-
ALS PF9250
OPE4709 G10474 and G10909
MEX 54 (Mahuku et al., 2004)
ties is probably the cheapest method of managing and problem. The use of to
are attacked by a combination of fungal, bacterial this viral diseases leading
Pythium root rot PYAA19 RWR719 (Buruchara et al)
poor yields (Fig. 1). The deploymentcould speed up the development ofvarie-
MDR parents in breeding programs of multiple disease resistant (MDR) MDR PF9250 G10474 and G10909
ties is probably the cheapest method of managing this problem. The use of PYB08 RWR719 719
RWR (Buruchara et al)
varieties. Marker Assisted Selection (MAS) o ers advantages within NARS Pythium root rot PYAA19
MDR parents in breeding programs could speed up the development of MDR
breeding programs in targeting challenging breeding objectives requiring com- Anthracnose SAB-3
PYB08 RWR 719 (Vallejo and Kelly, 2001)
G2333
varieties. Marker Assisted Selection (MAS) o ers advantages within NARS
plex breeding schemes.
breeding programs in targeting challenging breeding objectives requiring com- Anthracnose SAS-13
SAB-3 G2333 (Vallejo and Kelly,1998)
G2333 (Young et al., 2001)
plex breeding schemes. SBB-14 G2333 (Young et al., 1998) and Kelly, 2001)
G2333 , AB 136 (Awale
However, the national programs lack the facilities and capacity to use these SAS-13
techniques. Taking advantage of lackbiotechnology facility at Kawanda in
However, the national programs the the facilities and capacity to use these SBB-14
SH-18 G2333 , AB 136 (Awale and Kelly, 2001)
G2333 (Awale and Kelly, 2001)
Uganda, andTaking advantage of the biotechnologyutilizing molecular markers
techniques. the available markers, CIAT-PABRA is facility at Kawanda in BCMV SH-18
ROC11 G2333 (Awale and Kelly, 2001)
Various
Uganda, and the available markers, CIAT-PABRA is (Angular leaf Spot - ALS -
linked to resistance genes to three fungal diseases utilizing molecular markers
Pythium root rots and Anthracnose)fungal diseases (Angular leaf Spot - ALSMo-
linked to resistance genes to three and one viral disease (Bean Common - BCMV
BCMNV ROC11
SW13 Various
Various
saic Virus root rots and its necrotic strain one viral disease (Bean CommonVirus
Pythium (BCMV) and Anthracnose) and Bean Common Mosaic Necrotic Mo- BCMNV
CBB SW13 820
SAP Various et al., 2000, Deidre et al., 2007
Miklas
(BCMNV) (Table 1) .and its necroticpyramid the resistance genes Necrotic Virus
saic Virus (BCMV) The aim is to strain Bean Common Mosaic in common CBB SAP820 Miklas et al., 2000, Deidre et al., 2007
background in an e . ort of developing MDR parents that can bein common
(BCMNV) (Table 1) The aim is to pyramid the resistance genes utilized by
NARS breeding programs. developing MDR parents that can be utilized by
background in an e ort of Conclusions and Way Forw ard
NARS breeding programs. Conclusions and Way Forward
• Crosses between Pythium/ ALS resistance plants and Anth/ BCMV/
• Crosses between have been conducted plants and Anth/ BCMV/
BCMNV plants Pythium/ ALS resistance
BCMNV plants have been conducted
• MDR parents developed will be made available to NARS for utilization in
• MDR parents developed will be made available to NARS for utilization in
own breeding programs.
own breeding programs.
• We envisage a mechanism where the capacity of NARS in using MAS will
• We envisage a mechanism where the capacity of NARS in using MAS contact
be enhanced through this process with back up from continuous will
be enhanced through this facility in Kawanda. from continuous contact
with the biotechnology process with back up
with the biotechnology facility in Kawanda.
• Some partners have been trained (MAS and Disease Phenotyping)
• Some partners have been trained (MAS and Disease Phenotyping)
Fig 1. Some of the most common diseases of beans in Africa
Fig 1. Some of the most common diseases of beans in Africa
Marker Assisted Selection (MAS)
Marker Assisted Selection (MAS) Figure 2: Part analysis of the plants from the cross G2333 X MCM1015 using the ROC 11
Figure 2: Part analysis of the plants recessive bc-3G2333 Sample 5 is positive control 11
marker to detect presence of the from the cross gene. X MCM1015 using the ROC variety
marker to detect presence of the recessive bc-3 gene. Sample 5 is positive control variety
MCM 5001, Sample 1 is negative control RAB 487. Absence of a band indicates presence of
MCM 5001, Sample 1 is negativeband indicates absence of the gene. indicatesbp molecular
the gene while presence of a control RAB 487. Absence of a band L is 100 presence of
•• MAS refers to the use of DNA markers that are tightly-linked to target
MAS refers to the use of DNA markers that are tightly-linked to target the gene while presence of a band indicates absence of the gene. L is 100 bp molecular
marker.
marker.
loci as aasubstitute for or to assist phenotypicscreening
loci as substitute for or to assist phenotypic screening
•• MAS is the most promising application of DNA markers for cultivar de-
MAS is the most promising application of DNA markers for cultivar de-
velopment
velopment
Materials and Methods:
Materials and Methods:
•• Single crosses between sources of resistance, aim of screening up to
Single crosses between sources resistance, aim of screening up to
1500 FF2plants per cross
1500 2 plants per cross
•• MCM5001and MCM 1015 as sources of IIand bc- 3 genes for
MCM5001and MCM sources of and bc- 3 genes for
BCMV/ BCMNV
BCMV/ BCMNV
•• G2333—Co-4,,Co-5 and Co-7 for resistance to anthracnose,
G2333— Co-4 Co-5 and resistance to anthracnose,
•• RWR719 and MLB-49-89A-Pythiumroot rot,
RWR719 and MLB-49-89A-Pythium root rot,
•• MEX54- phg for resistance
MEX54- phg for resistance to ALS.
•• DNA extracted from leaves of 2 week old F2 plants
DNA extracted from leaves of 2 plants
•• Two mm discs used as templates in PCR reactions using speci cc mo-
Two mm discs used as templates in PCR reactions using speci mo-
lecular markers.
lecular markers. Figure 3: 3: Breeding schemedevelop Multiple Disease resistance parents to Angular leaf spot, spot, Anthracnose,
Figure Breeding scheme to to develop Multiple Disease resistance parents to Angular leaf Anthracnose,
Pythium root rot rot and BCMV/BCMNV
Pythium root and BCMV/BCMNV
•• Plants positive for 2-3 gene combination selected and double crosses
Plants positive for 2-3 gene combination selected and double crosses
conducted.
conducted.
References
References
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Awale, H.E., and J.D. Kelly. 2001. Development of SCAR markers linked to Co-42 gene in common bean. Ann.
Results Rept. Bean Improv. Coop. 44:119-120.
Results Rept. Bean Improv. Coop. 44:119-120.
Buruchara et al.
Buruchara et al.
Mahuku, G., Montoya, C., Henríquez, M.A., Jara, C., T eran, H., and Beebe, S. 2004. Inheritance and charac-
To date 10 out of 340 plants have been found to possess four gene combina- Mahuku, G., Montoya, C., Henríquez, M.A., Jara, C., T in the and Beebe, S. 2004. Inheritance and charac-
terization of the angular leaf spot resistance gene H., common bean accession, G 10474 and
eran,
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Sixty two out of 103 F2 plants have been found to posses both the Pythium and Young, R.A.,Rept. Bean Improv. Coop. 44:121-122.
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For more information: c.mukankusi@cgiar.org
For more information: c.mukankusi@cgiar.org