Lilium: Conservation, Characterization, and Evaluation

Abstract

Lilies are spectacular bulbous plants grown worldwide for cut flower and pot plant production. There are more than 110 species of Lilium which are divided into seven sections, and since species belonging to the same section have relatively high interspecific crossing abilities, interspecific hybridization is the prime method of lily breeding. The interspecific hybrids within the sections especially those within the sections Leucolirion, Archelirion, and Sinomartagon represent the most important breeding groups which are Longiflorum hybrids (L genome), Asiatic hybrids (A genome), and Oriental hybrids (O genome). Most of the natural lily species are diploid (2n = 24), but few species are triploid (2n = 3x = 36) that are sterile. Breeding of novel lily cultivars by either traditional cross or genetic engineering is possible only when valuable genetic resources are available. In recent years, lily habitats have been suffering serious destruction, and many wild species have become endangered. So, germplasm conservation is very important as a source of genetic variation for breeding and research and to prevent rare species from becoming extinct. Many in vivo and in vitro techniques have been employed to conserve Lilium germplasm, out of which cryopreservation, i.e., storage of living cells, tissues, or organs at extra low temperatures, usually that of liquid nitrogen (−196 °C), has been recognized as an ideal means for long-term storage of Lilium germplasm. The lily (Lilium longiflorum, Easter lily) genome size is 36 GB which is one of the largest among all plants, i.e., ~ 550x of Arabidopsis thaliana (135 Mb). Biotechnological tools like tissue culture, molecular markers, and recombinant DNA technology have played vital role for the development of Lilium cultivars with improved traits.