Discovery of novel traits in seed-propagated Lilium: Non-vernalization- requiring, day-neutral, reflowering, frost-tolerant, winter-hardy L. xformolongi. I. Characterization

Lilium are important floricultural crops worldwide. The objectives of this research were to examine L. xformolongi hybrids and a parental species (L. longiflorum) in photoperiods (Exp. 1) and environments (greenhouses, Exp. 1; field, Exp. 2) for flowering without vernalization, post-emergence photoperiod, potted plant/field performance, frost tolerance, and winter hardiness. Seed germination (4-15%) and yield potential (3.5-12.5%) varied between genotypes. In Exp. 1, short/long days had a significant effect on visible bud date only, but not on leaf unfolding rates, plant height, leaf number, or flowering dates; cultivar differences were highly significant. Cultivar × photoperiod interactions were nonsignificant except for flowering date (P = 0.04). 'Nellie White' (case-cooled bulbs) flowered in 213 d, while L. xformolongi cultivare took 247 d ('Sakigake Raizan') to 306 d ('Raizan No. 3') from sowing. Both VBD (h²= 0.93) and flowering date (h²= 0.91) were highly heritable (Exp. 1) and correlated. Regardless of photoperiod and environment, L. xformolongi flowered in <1 yr from sowing without cold. Leaf number (h ² = 0.81, Exp. 1) and unfolding rates (h²= 0.93) were not as tightly linked in L. xformolongi as 'Nellie White'. No seed-propagated hybrids (98-164 cm) were as short as 'Nellie White' (62 cm). 'Augusta F ₁ had the highest flower bud counts (6.9 / plant). Shoot numbers ranged from n=1 ('Nellie White') to n = 3.8 ('Sakigake Raizan'). L. xformolongi reflowered continuously in the field, but varied for frost-tolerance (25-75%; Exp. 2). Winter survival ranged from 0 to 87.5% in L. xformolongi over two years (Exp. 2). Flowering and reflowering of seed-propagated L. xformolongi in <1 yr. without vernalization, frost-tolerance, day neutrality, and winter hardiness are novel trait combinations for Lilium.