Conservation of the genetic resources of cassava (Manihot Esculenta) Determination of wild species localities with emphasis on probable origin

Genetic relatedness between cassava (Manihot esculenta Crantz) and M. flabellifolia and M. Peruviana based on both RAPD and AFLP markers

“…Their results, based on 93 AFLP markers, show that other naturally occurring species, such as flabellifolia, were genetically very closely related to the varieties of cultivated cassava: M. procumbens, M. fruticulosa, M. pentaphylla and M. pruinosa. On the basis of field observations, Nassar (1978) found that the fertility rate of crosses between M. oligantha (Pax) Nassar and cassava is about 90%, indicating that the former species can be classified in the primary genic pool, as proposed by Harlan and Wet (1971).…”

“…The three Mexican species are quite different from the Brazilian species. M. glaziovii occurs in the arid zone of northeastern Brazil, an important center of genetic diversity for the genus Manihot (Nassar, 1978). This species has been widely used to introduce genes of specific agricultural importance into cultivated cassava, especially because of the ease in producing desired crosses and the possibility of restoring the fertility of infertile hybrids (Léfèvre, 1989).…”

“…This species has been widely used to introduce genes of specific agricultural importance into cultivated cassava, especially because of the ease in producing desired crosses and the possibility of restoring the fertility of infertile hybrids (Léfèvre, 1989). M. reptans, a species much less used than M. glaziovii in genetic studies, is native to the humid regions of central Brazil, the most important center of diversity for Manihot (Nassar, 1978). The three species most distantly related to cultivated cassava are those native of Mexico, the second most important center of diversity for Manihot (Nassar, 1978).…”

“…According to Rogers and Appan (1973), the genus Manihot contains 98 species, one fifth of which are native to North America, while the remaining four fifths occur in South America. Harlan (1971) and Nassar (1978) identified the central region of Brazil as the main center of diversity for Manihot species, followed by two other centers in southern Mexico and northeastern Brazil. Manihot species are classified as sporadically distributed colonizing perennials commonly found in semi-arid regions or disturbed zones of humid regions (Rogers and Appan, 1973).…”

Caracterização molecular e análise filogenética do fitoplasma agente do superbrotamento da mandioca (Manihot esculenta) no estado de São Paulo

“…Nassar et al (1978) afirmaram ainda que a mandioca era cultivada nesta região por indígenas desde antes do descobrimento do Brasil e que a sua distribuição por toda a América do Sul foi auxiliada justamente por estes povos. Apesar desta proposição, existe a hipótese de que a origem da mandioca é a região amazônica, e que, a partir daí, a cultura imigrou para o Norte, chegando às Antilhas, à América Central e à América do Norte (SCHMIDT, 1951).…”