Biology Reference
In-Depth Information
and other Bt-cowpea safety concerns concluded
that the gene would escape into the wild, but
that the chance of negative environmental conse-
quences would be negligible (Murdock, personal
communication, 2012). Efforts have been initi-
ated in several West African countries to use the
marker-assisted breeding tools cited in this chap-
ter to introgress the Bt gene into locally adapted
varieties. If this MABC effort is successful and
effective seed delivery and resistance manage-
ment plans can be implemented, Bt -cowpea can
help dramatically increase grain yields of cow-
pea in regions of Africa with Maruca infesta-
tions, while reducing insecticide inputs and the
negative health risks and environmental damage
associated with insecticide use.
The most important pest of stored cowpea is
the bruchid beetle, or cowpea weevil. Even low
initial infestation rates can cause significant grain
damage because of the high fertility and short
generation periods of this pest. As noted above,
only low to moderate levels of resistance have
been found, which provide only limited storage
protection (Murdock et al. 2008). Genetic engi-
neering has been used to transfer the gene cod-
ing for the
formed cowpea carrying
AI-1 exhibits near
immunity to the cowpea weevil (Solleti et al.
2008). However, food safety concerns have con-
strained the development and release of this valu-
able product.
α
Tools and GeneticResources for
Cowpea Breeders
A computer program called 'BreedIt C SNP
Selector' ( www.BreedIt.org) has been developed
at the University of California, Riverside, which
integrates fingerprint information, marker-trait
association information, and the genetic map.
It allows breeders to choose a set of custom
markers based on markers that are polymorphic
between parental lines, marker interval distance,
and marker association with target traits.
Eleven RIL populations have been described
in the international cowpea community. Most
populations were developed with the goal of
mapping specific high priority traits, and these
population resources are described in Table 10.3.
Challenges forAdoption of Modern
Breeding Tools in Cowpea
Improvement
AI-1, a bruchid
resistance factor from the common bean, into
cowpea (Solleti et al. 2008). The
α
-amylase inhibitor
α
α
-amylases, the
A suite of prospective molecular markers and
genomic tools for modern breeding are now
available in cowpea. Will these resources be
target of
AI-1, are key enzymes for starch diges-
tion and vital for bruchid development; trans-
α
Table 10.3. Cowpea RIL populations available for marker-trait
association and partial list of biotic stress resistance traits segregating.
Population
Individuals
Segregating biotic traits
CB27 x IT97K-556-6
92
Cowpea aphid
CB27 x IT82E-18
160
Foliar thrips
CB27 x UCR 779
56
Cowpea aphid
CB46 x IT93K-503-1
114
Macrophomina, foliar thrips
524B x IT84S-2049
85
Multiple, described in text
Dan Ila x TVu-7778
79
Bacterial blight
Yacine x 58-77
97
Flower thrips
Sanzi x Vita 7
122
Flower thrips
TVu14676 x IT84S-2246-4
136
Striga
CB27 x 24-125B-1
87
Root knot nematode
LB30#1 x LB1162 #7
90
Rust and powdery mildew
 
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