In this paper, five studies on diversity in the plant genus Chaenomeles are summarised. Genetic resources in the genus Chaenomeles were evaluated using molecular markers and morphological characters. Population differentiation and diversity were estimated in cultivated and wild plant material. In agreement with studies on cultivated Chaenomeles material, native material of C. japonica was strongly differentiated from C. speciosa, C. cathayensis and C. thibetica. Populations of C. japonica and C. speciosa were considerably more diverse than populations of C. cathayensis and C. thibetica. Furthermore, evidence of spontaneous hybridisation in native populations between C. cathayensis and C. speciosa was obtained. Random amplified polymorphic DNA markers and morphological characters revealed concordant patterns of genetic relatedness among the offspring families studied. To increase diversity in breeding populations and collections, different strategies for sampling of wild plant material are proposed for C. japonica and C. speciosa on the one hand, and C. cathayensis and C. thibetica on the other
