Intergenomic recombination and introgression breeding in Longiflorum x Asiatic lilies

Lily, one of the economically most important ornamental crops, belongs to the genus Lilium of the family Liliaceae. There are about 80 species in Lilium which are categorized into seven sections, i.e., Lilium, Martagon, Pseudolirium, Archelirion, Sinomartagon, Leucolirion and Oxypetala. Usually, it is not so difficult to cross between the species within each section and the hybrids are fertile. However, it is very difficult to cross the species belonging to different sections. With cut style pollination followed by embryo rescue techniques, such distant interspecific crosses can be possible, but the hybrids are highly sterile. All modern lily cultivars have originated from hybridization among wild lily species. The three main lily cultivar groups, viz., Longiflorum, Asiatic and Oriental, originated from hybridization within one section, i.e., Leucolirion, Sinomartagon and Archelirion respectively. Up to now, about 150 Longiflorum, 4000 Asiatic cultivars, and 2000 Oriental cultivars have been registered. The genomes of Longiflorum (Leucolirion), Asiatic (Sinomartagon) and Oriental (Archelirion) are represented as L (Longiflorum), A (Asiatic) and O (Oriental) genome respectively. They possess quite different valuable traits, and one of the main goals of modern lily breedingareto combine the three distinctive groups in new cultivars. In this thesis, crosses among diploid Asiatic and Longiflorum cultivars, diploid F1 LA hybrids, triploid BC1 cultivars, allotetraploidand allopentaploid lilies were made. 11 diploid F1 LA hybrids and 19 triploids BC1 cultivars which were supplied by the Dutch lily breeding companies, and 23 new BC1, five BC2 and seven BC3 progenies were analyzed with conventional cytological methods, flow cytometry and genomic in situ hybridization.The configurations of metaphase I during meioses of the F1 LA hybrids are quantitatively variable, ranging from no bivalent to 12 bivalents in different pollen mother cells. This implies that LA hybrids hav