Abstract:

Lilium davidii var. unicolor is the most important edible sweet lily in China. To cultivate new， high-quality germplasm of L. davidii var. unicolor， bulblets growing in vitro were treated with different concentrations of colchicine， and mutagenic seedlings were obtained via adventitious bud induction. The variant lines were further identified by chromosome ploidy level， morphological， and inter simple sequence repeat （ISSR） molecular marker analyses. The results indicated that treatment of the bulblets with 0.15% colchicine for 48 h was the optimal induction method， leading to the maximum mutation rate of 58.06%. Two fast-growing seedlings with stable morphological variations were selected for chromosome ploidy analysis by flow cytometry and tableting in the root tip. The proportion of cells containing 36 chromosomes in the root tip of one induced line was 80%， indicative of a homozygous triploid. Compared with the control， the seedlings of the mutated lines showed significant differences in the leaf， bulblet， and roots. The guard cells were larger and the stomatal density was significantly reduced in the mutated lines compared with the control. Analyses of ISSR markers revealed genetic variations in the two mutagenic lines compared with the control， with mutation rates of 19.64% and 20.91%， respectively. Together， these results provide an important basis for obtaining triploid germplasm of L. davidii var. unicolor， and for breeding of new lily materials using colchicine treatment.

Key words: Lilium davidii var. unicolor, polyploid, colchicine, ISSR marker