CBN-V Video Archives - S6-18
AFLP and SSR Polymorphism: Evidence of Significant Levels of Introgression from Manihot glaziovii and M. carthaginensis into Traditional Varieties of Cassava in their Area of Origin

Morillo E¹., F. Fuenmayor², P. Cesar de Carvalho³ and G. Second⁴

1. Instituto Nacional de Investigaciones Agropecuarias (INIAP, Quito, Ecuador and Institut de Recherche pour le Dévelopement (IRD), Montpellier France
2. Centro Nacional de Investigationes Agropecuarias FONIAP-CENIAP, Maracay, Venezuela
3. Escuela de Agronomia, Universidad de Bahia, Cruz das Almas, Brazil
4. IRD and Pontificia Universidad Católica del Ecuador -PUCE- P.O. Box 17-01-2184, Quito, Ecuador second@ird.fr

        Mapped SSR and AFLP were used as evidence of introgressions in a set of 60 plants: from South America were 26 M. esculenta plants and six M. flabellifolia; from North-east Brasil and Africa were nine plants of M. glaziovii. Others included M. carthaginensis (six), M. quinquepartita (two) and M. brachyloba (three), various “tree cassava” (seven) and a triploid traditional variety. AFLP and SSR bands that appeared in some varieties of cassava but not in M. esculenta ssp. flabellifolia, the presumed ancestor of cassava, were considered as candidate introgressed bands. Some of these presumed introgressed bands are being sequenced. In the case of AFLP, the sequence of one band has so far allowed to design new primers to amplify part of the same sequence also in flabellifolia sp. It confirms introgression from M. glaziovii in some cultivars. Most interestingly, the mapped SSRs show that a chromosome segment located on the D linkage group was introgressed from M. glaziovii, not only in one of the parent of the cassava genetic map but also in various traditional cultivars that originated in South America (from Argentina to Mexico). This chromosome segment is believed to bear resistance genes to both CMD and CBB.

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