Variations in colchicine-induced autotetraploid plants of Lilium davidii var. unicolor

Colchicine-induced polyploid plants exhibit more variations not only in morphology and cytology but also in genomic DNA sequence. In this study, tetraploid Lanzhou lily (Lilium davidii var. unicolor) plants were induced by colchicine, and the factors that affected the tetraploid induction rate, including pre-culture duration and colchicine concentration, were examined. The results showed that both pre-culture duration and colchicine concentration exerted significant effects on the tetraploid induction rate. The highest tetraploid induction rate (33.33%) resulted from a 15-day-preculture treatment followed by soaking in 0.025% colchicine solution for 24 h. The ploidy levels of the regenerated plantlets were confirmed by flow cytometry analysis and chromosome number counting. The variations in morphological and cytological characteristics, as well as genomic DNA sequences of colchicine-induced tetraploids and diploids, were compared. The results indicated that tetraploids shared less leaf numbers, more leaf width, lower stomata density, and longer guard cell length. Moreover, inter-simple sequence repeat assay revealed notable genetic variations in the genomic DNA sequence between tetraploids and diploids, and the 75% polymorphism between them indicated that the variation in DNA sequence occurred during the chromosome doubling. Key message Colchicine-induced tetraploid Lanzhou lily plants exhibited variations not only in morphology (including leaf number and leaf width) and cytology (including stomata density and guard cell length) but also in genomic DNA sequence.