ABSTRACT
Plant breeding is most often identified as a function of the agricultural system which aids in ensuring a sustainable supply of food. One of the biggest threats to this supply of food is massive crop failure due to adverse climate or pathogen attack. Modern agriculture is dependent upon a relatively small number of commercial crop species, each of which is dominated by a relatively small number of varieties. The most important of these natural centers of genetic diversity are to be found in the twelve tropical and subtropical areas of the world known as Vavilov Centers. The Vavilov Centers, in most cases, are tropical and subtropical areas in third world countries with high rates of population growth and extremely fragile environments. The ex situ situation, however, is not an ideal alternative. It is obvious that ex situ storage of germ plasm is relatively short term--on the order of 50-100 years.
