Re-emergence of Lilium callosum Sieb. et Zucc. in Taiwan after a fire allows propagation and renews the possibility of conservation

Abstract

Background Lilium callosum is native to Taiwan, but little is known about it since it has been considered extinct since 1915. After the rediscovery of this rare species after a fire in 2011 in Tunghsiao Township, intensive work has been conducted to count the number in the wild population, to develop a conservation strategy, and to understand its reproductive characteristics and even economic potential.ResultsTo conserve the germplasm of this population, three scales from a wild L. callosum plant were collected to establish a mass propagation system. Flowers from two regenerated plants were crossed by hand-pollination, the ovules were rescued and cultured in vitro, and 10 offspring were obtained. The karyotype was determined to be 2n = 2x = 24 = 2m + 2m(sat) + 2sm + 8st + 10t. The phylogenetic analysis using ITS sequences revealed that the sample of L. callosum from Taiwan was not grouped with the other accessions of L. callosum from other regions. The native habitat is classified as grass-dominated vegetation at the early successional stage and a subtropical monsoon-type climate. To clarify the causes of population scarcity in the native environment, reproductive characteristics of regenerated plants were investigated.ConclusionsBased on the information from this study, it is possible that factors intrinsic to L. callosum could combine to limit pollination and seed formation. The L. callosum pollen only germinated at a temperature that was higher than the native environment, the plants are self-incompatibile, there was a and scarce population, scattered flowering time and dichogamy. Through the culture of these wild harvested parts, the diversity of the germplasm has been broadened and is now available to preserve this rare and valuable species for the future.Electronic supplementary materialThe online version of this article (10.1186/s40529-017-0202-x) contains supplementary material, which is available to authorized users.

Embryo Rescue in Plant Breeding

“…L. callosum is a widespread species in Asia, distributed from Taiwan to northern Russia. However, phylogenetic analysis using ITS sequences demonstrated that L. callosum from Taiwan is not clustered with other L. callosum accessions [456]. A limiting effect on the fitness of L. callosum in Taiwan was found to be the inability to produce meagre numbers of seeds in the native habitat.…”

“…Once rediscovered, the species was micropropagated by culturing scales of the bulb on a modified basal MS medium [72] supplemented with 0.1 mg L −1 NAA, 0.1 mg L −1 BA, 1 g L −1 casein hydrolysate, and 3% sucrose. The explants were maintained at 25 ± 1 • C with a 12 h photoperiod and a light intensity of 5.6 µmol m −2 s −1 [456]. In addition, flowers from two regenerated plants were crossed by hand pollination, and immature ovules were cultured in vitro.…”

“…This certainly limits the genetic variability in the population, leading to the phenomena of genetic drift. Chen et al [456] used the ER strategy to conserve germplasm, and this approach could be critical for the conservation of L. callosum in Taiwan. The lily is a globally important commercial flower crop.…”