Genetic resources, also named germplasm resources or germplasm collections, generated with human activities and agricultural origins, are the most important component of biodiversity. Genetic resources are closely related to the survival and development of human being. They are constantly innovating and developing, and are the most fundamental material basis and strategic resources for human reproduction and development. Genetic resources for crop species are also fundamental for breeding and the sustainable development of agriculture. Scientists on crop breeding areas have attached great importance and interests on the collection and preservation of genetic resources, especially during the late of the last century. Thus, there was an upsurge in the collection, conservation, and evaluation of germplasm resources all over the world, and core collections had been constructed for many crops in the past decades, to make a better use and management of collections.