To increase the variation of flower size of Lilium x 'Asiatic Hybrids', L. dauricum were reciprocally crossed with L. concolor. The hybrid progenies were forced into bloom to check the characteristics for cut flower production. 1. No seed set in the cross of L. concolor X L. x 'Asiatic Hybrids' by normal and cut-style pollination. 2. In the reciprocal cross, hybrids were obtained by using cut-style pollination and embryo culture. The ovary set rate was 100%, but the endosperm was lacking or it developed slightly into a watery mass. When the emryos were 1 to 6 mm long, they became callus-like and distorted. The average number of embryos per ovary was 5.1 and ranged from 0.5 to 21 in 26 cross combinations. The hybrid seeds did not germinate in vermiculite. 3. In the cross between L. dauricum X L. concolor, the length of embryos ranged from 4 to 6 mm when they became distorted. They appeared normal compared to progenies between L. x 'Asiatic Hybrids' X L. concolor. The hybrids-seeds also did not germinate in vermiculite. 4. The survival rate in embryo culture varied among the crosses but averaged 47.4%. 5. Although the average pollen fertility rate among 11 hybrids was 72.9%, the effort to backcross the hybrid with their parents met with limited success. Hybrids produced many seeds when backcrossed with L. concolor, but a few seeds were obtained from L. x 'Asiatic Hybrids'. When the parents were pollinated with hybrid pollen,'Asiatic Hybrids' produced many seeds, but L. concolor produced no seed. About the half of the seeds obtained from backcrosses were abnormal and only 20.3 to 34.0% germinated in vermiculite. When immature embryos were excised and cultured, the survival rate was increased above 73.6%. 6. Flowers and leaves of hybrids were intermediate between their parents; the hybrids grew vigorously, having longer stems, more flowers per inflorescence than thier parents. Hybrids were similar to L. concolor rather than L. x 'Asiatic Hybrids' because of their relatively small flowers and slender leaves. 7. The number of days to flowering was about 90 when hybrids were forced in winter, and about 65 when they were cultured after the bulbs were harvested and stored at -2 degrees C in autumn. The hybrids were evaluated for their cut flower production and the more promising progenies were selected to serve as mother plants for further breeding.
