Domestication of the cultivated lily (LiliumL.)

Compared with other ornamental crops like rose, chrysanthemum, tulip and narcissus, the breeding history of lily is rather short. The first steps were made less than one century ago. The first crosses involving Liliummaculatum, L. davidii, L. dauricum, L. bulbiferumand L. tigrinumwithin the section Sinomartagon were produced in Japan and the US. A breakthrough for the lily culture was the mid-century hybrid ‘Enchantment’ bred by Jan de Graaff in 1944. In 1977, 760 hectares of this cultivar (74% of the total acreage of lily bulbs) were grown in the Netherlands. The first polyploid Asiatic lilies (triploids and tetraploids) were introduced in the eighties of the 20th century. Nowadays most of the Asiatic hybrids are polyploid. After the Second World War, Dutch companies became leaders in lily breeding activities. In the first years (1970-1990) that lily culture gained significance, only Asiatic hybrids were grown. In the next period, the Oriental hybrids, originating from crosses ofmainly L. auratumand L. speciosumfrom the Archelirion section, were developed. These hybrids, with large, fragrant, mainly pink and white flowers became the most important hybrid group during the 1990’s. ‘Star Gazer’ was the first up facing Oriental hybrid and for more than 25 years it was the most important cultivar in this group. From that time forward, this grouphas been the most important group of lilies. Meanwhile intersectional hybridisation, due to advanced interspecific hybridization methods (embryo rescue and pollination techniques) yielded its first commercial products. Lily became a model crop for research in interspecific hybridisation and molecular cytogenetics. The first group of intersectional hybrids, the Longiflorum × Asiatic hybrids (LA), was developed by interspecific hybridization between hybrids of different sections. These LA hybrids are backcrosses from a 2n producing or a chromosome doubled F1 LA hybrid with an Asiatic hybrid and are, therefore, in general, triploids. Triploids possess a superior growth vigour and plant habit which appear to be the most favourableploidy level. In the last ten years, this group has become more important than the Asiatic hybrid group and has in large part, replaced them in the industry. Similarly, other intersectional hybrids have been developed, such as the LO (Longiflorum × Oriental), LR (Longiflorum × Rubellum), OT (Oriental × Trumpet) and OA (Oriental × Asiatic) hybrids. Like the LA-hybrids have mainly replaced the Asiatic hybrids and the LO-hybrids have replaced the Longiflorums, it can be expected that, in the future, the Oriental hybrids will be partially replaced by the OT’s. It is clear that in the last 15 years dramatic changes of the assortment have taken place. For the near future molecular breeding in lily show promising developments in research. Progress is made the development of markers for breeding of Lilium. Especially the development of massive parallel sequencing methods known as NGS sequencing and the availability of high throughput marker systems resulted in new genetic maps of lily with markers closely linked to resistance genes.