The document summarizes efforts to develop common bean varieties in Rwanda resistant to Bean Common Mosaic Necrotic Virus (BCMNV) using Marker Assisted Selection (MAS). Researchers screened 219 bean varieties and identified genes conferring resistance. They developed 86 breeding lines by crossing donor lines containing resistance genes with local varieties. These lines were selected using linked markers and for resistance to BCMNV and other diseases. Participatory plant breeding involved farmers in selection. The integration of conventional breeding and MAS was successful in pyramiding resistance genes and developing lines adapted to Rwanda.

1. Application of Marker Assisted Selection(MAS) for the improvement of Bean Common Mosaic Necrotic Virus
in Common bean (Phaseolus vulgaris)
*Gerardine Mukeshimana, Gregoire Hagenimana, Francoise Murorunkwere, Emmanuel Bigirimana
National University of Rwanda
• Five bc-3 gene donors bean lines (USWK-6,
Introduction Activities TARS VAR-7, USCR-7, USCR-9, TARS VAR-1)
•Assemble and evaluate landraces, released were crossed with local bean cultivars RWR 719,
Common bean is the second most important varieties, elite and promising bean germplasm for RWK 10, RAB 487, MLB-49-89A, MLB 49-89A,
source of human dietary protein and the third the presence of the I gene which results in black RWR 1946., RWV523, CAB 19, NG 224-4,
most important source of calories of all root against BCMNV using both field, greenhouse, SCAM80CM115, RWV167, G2331, and RWR
agricultural commodities produced in eastern and markers SW 13 linked to the I gene 2075. A total of 86 segregating lines at different Fig3. screening for the bc-3 gene using ROC11
and southern Africa. However, Bean production •Integrate conventional Breeding and marker levels consisting of 18 F2, 27 BC2F4:5, 24 marker
is always below the optimum in these areas due assisted selection (MAS) using SW 13 and ROC11 BC1F1:5, and 8 BC2F1:5 were developed and • One Rwandan student was trained at MS level
to various production constraints. Disease and markers linked to I and bc-3 genes to improve selected for BCMNV resistance as well as other and her research involved the use of MAS in
pests rank high among bean production resistance to BCMV and BCMNV in common bean common bean diseases in Rwanda. Field and Plant breeding; two undergraduate students, one
problems. Bean common mosaic virus (BCMV) •Enhance consumer acceptability by involving markers SW13 and ROC 11 were used in BCMNV of them now a researcher at ISAR; and a lab
and bean common mosaic necrotic virus farmers in varietal selection in early generation resistance selection. Most of these lines are being technician were trained in the use of markers in
(BCMNV) are the most economically important selections tested in multi-locational trials breeding
viral diseases affecting common bean in eastern •Enhance local capacity in plant breeding and the
and central Africa. They may cause up to 80% used of biotechnology approaches in bean breeding Conclusions
yield loss in common bean. •Most of the local bean germplasm in Rwanda are
Breeding for BCMV and BCMNV resistance is Results susceptible to BCMV and BCMNV
the only viable method to prevent yield losses • 219 bean germplasm were screened for BCMV
in that region since BCMNV strains are found and BCMNV using field in Rubona (hotspot for •The integration of conventional and markers linked to
in wild legumes. Genes conditioning resistance BCMV and BCMNV). Only 28 genotypes showed I and bc-3 genes has successively been able to
to BMNV have been characterized. Pyramiding no symptoms in the field. The marker screening Fig2. Field Screening of advanced lines from a pyramid these genes in bean breeding
of the I and bc-3 genes would condition cross USCR-7X RWK10 (2 middle rows) for
using SW13 marker linked to the I gene showed •The need of stakes has to be addressed otherwise it
resistance to all strains of the two viruses that 17 genotypes out of 28 had the “I” gene resistance to BCMNV under natural infection from
may compromise the climbing bean production
the local susceptible cultivar Nakaja
Objective Participatory plant breeding was introduced in the Acknowledgements:
To develop high yielding varieties of major selection of these lines by involving farmers at • ASARECA
market classes that are resistant to bean flowering and maturity stages. • Ginés-Mera Memorial Fellowship Fund
common mosaic virus (BCMV) under Results showed that farmers selection criteria • Robin Buruchara
environments prone to BCMNV. were: Determinate architecture since these do not
need stakes which are expensive Bibliography
• High yielding in terms of number of pod G. Mukeshimana et al.2005. Markers linked to the
*Corresponding author: • Resistance to diseases bc-3 gene conditioning resistance to bean common
Fig1. Screening of bean germplasms using the
mukeshim@msu.edu • Vigor since they can resist to wind and mosaic potyviruses in common bean.
SW13 marker Euphytica 44: 291-299
maintain flowers under excessive rain