Study on the homology of the genomes of tetraploid Asiatic lilies (Lilium) using FISH

Abstract

Asiatic lily cultivars, bred by hybridization and (or) chromosome doubling of species of section Sinomartagon of Lilium, are diploid, triploid, or tetraploid, but the homology of the genomes among species of section Sinomartagon and Asiatic lilies remains unclear. In the present research, two tetraploid Asiatic cultivars were analyzed, using 45S rDNA as probe, for their FISH karyotypes and their chromosomal association, anaphase I, telophase II, and pollen viability were surveyed to assess the multivalent segregation. Chromosomal assortment of six progenies of the two tetraploid cultivars were also investigated. The results showed that the tetraploid cultivars had similar FISH karyotypes, they predominantly formed multivalents, and these were equally separated because their anaphase I, telophase II, and pollen viability were similar to those of diploid species. Apart from minor variations, FISH karyotypes of progenies were similar to each other and to their parents. Based on these results and considering the high crossability among species of section Sinomartagon and (or) Asiatic lilies, we concluded that species of section Sinomartagon and their resulting cultivars share a common genome; thus, polyploidy Asiatic lilies are autopolyploid.