Biology Reference
In-Depth Information
A fast track scheme:
West Africa:
crosses to CMD
resistance source
Seedling nursery
East Africa:
Crosses into
genetic
backgrounds
with CBSD and
CMD - a two
step process
(Selection for disease and vigor)
Single row trial
(& rapid in vitro multiplication)
Genotyping
(Agroecology based multi testing)
Crossing block
(Recurrent selection scheme)
Advanced yield trial
(& rapid in vitro multiplication)
4 agroecologies
)
(
UYT &
Farmer participatory testing
Fig. 15.11.
A Marker-Assisted Selection-based fast-track evaluation scheme implemented in the cassava breeding commu-
nity of practice in Africa, leading to release of cultivars in 5-6 years. For a color version of this figure, please refer to the color
plate.
MAS has facilitated the introgression of CMD
into backcross derivatives of wild relatives devel-
oped for novel traits, which have now been intro-
duced into Africa to add value to the crop. The
novel traits include high nitrogenous compound
(potentially reflective of high protein levels) and
dry matter contents, delayed post harvest phys-
iological deterioration, and drought tolerance.
The next wave of LA genotypes to be released
as cultivars in Africa will come from the set
of germplasm selected for root quality traits
(delayed-PPD and high protein content). Follow-
ing success with MAS, Nigeria is now develop-
ing capacity in MARS (marker-assisted recurrent
selection) in identifying complex traits such as
drought tolerance, with technical support of the
CGIAR GCP.
To improve access to genomic studies and
MAB,
Breeding Platform (IBP) to provide service sup-
port to developing countries to improve their
capacity in modern breeding through the cas-
sava breeding CoP. The platform provides online
one-stop shopping with centralized and func-
tional access to MAB technologies, value-added
germplasm, cost-effective marker services lab-
oratories, data management, and analysis tools.
Through efficient marker technologies offered by
the platform, NARS are able to overcome techno-
logical bottlenecks in MAB (Ribaut et al. 2010).
Ex ante impact assessment studies indicate
that cultivars developed with marker-assisted
breeding that incorporates CMD and CGM resis-
tances and delayed PPD are worth US$2.89 bil-
lion in Nigeria, US$854 million in Ghana, and
US$280 million in Uganda over 20 years. If these
cultivars were to be developed with resistance
to CMD and green mites alone they would be
the
GCP
has
initiated
the
Integrated
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