Article Keeping Options Alive and Threat of Extinction: A Survey of Wild Cassava Survival in its Natural Habitat By

Abstract

Wild cassava,  Manihot spp. are sources of many useful characters. Their occurence in natural habitats is diminishing day after day   and a number of them almost have come to extinction. It is suggested that in situ conservation should be followed. It is appealed to concerned authorities to make  an effort for their salvation. Key words: Manihot spp. Conservation, genetic resources, extinction, in situ Cassava is an important food crop for more than 900 million people in the tropics and subtropics. Its wild relatives are sources of many useful chracters  such as high protein content (Nassar,1977,  Nassar and Dorea,1982),  tolerance to drought  (Nassar,1978, 1991,  1996)  and apomixis (Nassar,1995,  Nassar et al.1997,1998,2000).  Every year from 1977-2001 wild species were collected,propagated, maintained in a living collection, evaluated and ferilized with cassava. This process both transferred useful traits and broadened this crop genetic base (Nassar,1986,1997,2000). Results of this program were published in a seies of publications, most recently in a chapter of advances in Agronomy (Nassar,1999). To determine localities of wild Manihot species Rogers and Appan monograph  (1973) was consulted. The  herbarium of   Universidades of Brasilia and Goias too. Trips were made to localities two times per year. Replications of trips to localities were made to assure finding the species because majority of wild Manihot species  native to Central Brazil are shruby and have their vegetative parts die back to the ground surface in dry season. Therefore ir is necessary to look  for the species  in both of the rainfall and dry seasons. Results of  occurence survey of these species in their natural habitats is shown in tabl