This study was carried out to overcome the problems that impede genetic improvement of Lycoris. An improved ovule culture method was developed to rescue the abortive embryo in order to overcome the poor fertility in hybridization of Lycoris. Using this method, a large number of selfed and crossed plants in several species were produced, and the interspecific hybrids which used L. incarnata (sterile) as a cross parent were obtained for the first time. Cytological studies of the S₁ plants indicated that polyploidization and aneuploid reduction caused by self-pollination should be among the major factors affecting karyotype evolution in some Lycoris species. Allozyme segregations in polymorphic loci of APT, GOT and EST were observed in S₁ of five diploid species, suggesting that each of the species is originally heterozygous. The investigation using genomic in situ hybridization (GISH) was done to clarify the chromosome constitution in Lycoris. The distinction between M + T and A type chromosomes at the DNA sequence level demonstrated that genome differentiation has occurred in the genus Lycoris.