Hybridization of Lilium leichtlinii var. maximowiczii with Longiflorum × Asiatic and Asiatic cultivars and identification of the hybrid progeny

Lilium leichtlinii var. maximowiczii is known for its tolerance of cold and shade and its strong adaptability to the environment. To breed new cultivars with these traits, L. leichtlinii var. maximowiczii was used as male parent to hybridize with some Longiflorum × Asiatic (LA) cultivars, Asiatic cultivars and Lilium lancifolium. In 15 crossing combinations with LA cultivars, nine developed swollen ovaries and six showed high rates of seeds with embryos. In 11 crossing combinations with Asiatic cultivars, only three had embryo seeds. Four strains were randomly chosen from the seedlings of the crossing combination Lilium LSQUORenoir' (A) × L. leichtlinii var. maximowiczii, and were numbered B-1, B-2, B-3 and B-4. Fluorescence in situ hybridization (FISH) technology was used to detect the number and sites of 45S rDNA for the hybrid progeny and parents. The male parent had eight signals, all of which existed in pairs. Lilium 'Renoir' had seven 45S rDNA signals, some of which existed singly. B-1, B-2 and B-4 had eight 45S rDNA signals, while B-3 had nine. The four strains the signals on chromosome 6 as L. leichtlinii var. maximowiczii, near the end of the long arm. We conclude that they were true hybrids. Crossing combinations with natural triploid L. lancifolium also yielded high rates of seeds with embryos.