In order to introduce new characters such as resistances, flower shape and colour, from wild species into the cultivar assortment of lily it is necessary to overcome interspecific crossing barriers.. Several techniques have been used for wide interspecific lily crosses with species and cultivars from the different sections of the genus Lilium (L. longiflorum, L. henryi, L. canadense L. concolor, L. dauricum, L. candidum, L. rubellum, L. martagon, Asiatic and Oriental hybrids). Hybrids originating from intersectional crosses (e.g. L. longiflorum x L. concolor, L. longiflorum x L. dauricum, L. longiflorum x L. henryi, L. longiflorum x L. martagon, L. longiflorum x L. candidum, L. longiflorum x Asiatic hybrids (LA), L. longiflorum x Oriental hybrids (LO), L. longiflorum x L. rubellum, L. longiflorum x L. canadense, Oriental x Asiatic hybrids (OA) and L. henryi x L. candidum) have been produced. Especially the Oriental x Asiatic hybrids are a break-through in lily breeding and a promise for the future. In general wide interspecific lily hybrids show F1-sterility. Using chromosome doubling techniques tetraploids with restored fertility are produced from these diploid hybrids. At this moment a crossing programme at polyploid level with these hybrids is being carried out.