S6-08
DNA Marker for Distinguishing
between Low-cyanide and High-cyanide Cassava Varieties
Dossou-Yovo I., J.H. Mignouna, J. Machuka and M. Bokanga
International Institute of Tropical Agriculture (IITA),
P.M.B. 5320, Ibadan,
Nigeria m.bokanga@cgiar.org
Cassava
breeding programs routinely measure the content of cyanogenic compounds
in cassava roots at harvest using either the rapid but less accurate
picrate method or the more accurate but complex enzymatic method.
This paper presents the first DNA marker for the cyanogenesis
trait in cassava. Four out
60 RAPD primers tested gave a polymorphism enabling to distinguish
between low-cyanide and high-cyanide varieties.
Through Bulked Segregant Analysis, it was confirmed that the RAPD
primer OPT-07 gave a polymorphic band at 850 bp in low-cyanide
varieties, which is absent in high-cyanide varieties.
Such marker will be
useful in the identification of low-cyanide genotypes, not only at
harvest time, but at any stage of the cassava plant growth cycle.
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