Plant Life 36: 99-100 (1980)
LYCORIS: FROM SEED TO FLOWER IN LESS THAN TWO YEARS
Margot Williams *

* Horticulturist, U.S. Department of Agriculture, Science
and Education Administration, Agricultural Research.
U.S. National Arboretum, Washington, D.C. 20002.

Breeding Lycoris can be rewarding, but requires patience since a seedling can take as long as 10 years to reach flowering size. Caldwell (1962) reported that he never had a seedling bloom in less than 6 years. A method by which generation time can be shortened would be a valuable tool for the Lycoris breeder. The investigation reported here was carried out to see whether a non-traditional method of germinating Lycoris seeds would shorten the time from seed to flower.

MATERIALS AND METHODS

A series of interspecific crosses was made in 1977 among plants in the Lycoris collection at the U.S. Plant Introduction Station, Glenn Dale, Maryland. A good seed crop was obtained. Immediately following harvest, seeds were sown in flats of shredded sphagnum moss which was moist but not soggy, and placed in a partially shaded lean-to greenhouse for germination. The seeds were placed on the surface of the medium and pressed in lightly; however, they were not covered by the medium. The seed flats were covered by a pane of glass raised about 1-1/2" inches from the edge of the flat by means of a wooden frame the size of the flat. This treatment effectively maintained a moist environment. The flats were watered as necessary to keep the sphagnum moist. Planting dates and germination dates were recorded for each Seedling. Seedlings were left in the seed flat until bulb-like thickenings were observed (2-3 weeks after germination), and were then transplanted to 2-inch pots, using shredded sphagnum moss as the potting medium. The young seedlings were planted so that only the basal 1/3 of the bulb and the roots were below the surface of the potting medium. After potting, the seedlings were placed in a hardening-off bench under intermittent mist (one 1-minute cycle per hour) for 1 week. The pots were then moved to a sunny greenhouse heated to 68°F at night, where the pots were plunged in a bench containing moist peat moss. No supplementary lighting was used.

** Mention of a trademark or proprietary product does not constitute a
guarantee or warranty of the product by the U.S. Department of Agriculture.

When the roots emerged from the drainage hold in the bottom of the pot, the seedlings were transplanted into 3-inch pots containing a 1:1:1 mixture of sand, soil, and peat moss. The transplanting procedure to larger pots was repeated each time root growth emerged through the drainage hole, to a maximum pot size of four inches. At each transplanting, the bulbs were lifted so that only the basal 1/3 was covered by soil. Lycoris bulbs tend to work themselves downward in the pot after planting. When it was observed that bulbs in 4-inch pots were submerged in soil, they were again lifted and replanted in 4-inch pots. Two weeks after each transplanting, the seedlings were fertilized with Mag-Amp**, a granular 7-40-6 slow-release fertilizer, at the rate of 1 teaspoon per 3-inch pot. As the oldest leaves became senescent, they were removed from the plants.

RESULTS

All seeds germinated within 4 to 6 weeks after sowing in the flat. At 3 to 4 months after sowing, all seedlings had produced at least one pair of leaves. At the time of this writing (2 years after performing the initial pollinations), bulb sizes range from 1/2 to 1-5/8 inch in diameter. Two seedlings have flowered. One seedling, a cross between a hybrid (L. elsiae x L. chinensis) and L. radiata, reached the flowering state in less than two years dated from the time the original cross was made. The second seedling to come into flower, a cross between L. radiata and L. aurea, flowered 27 months after the cross was made.

DISCUSSION

This treatment has potential for reducing generation time in Lycoris. It is hypothesized that light is a factor in inducing early germination since all other reports involve covering the seed. Creech (1952) reported that hybrid Lycoris seeds sown in a flat of sandy soil in October (immediately following harvest) germinated by the following spring, although foliage was not produced until the following October. Caldwell (1962) reported that sowing seeds 1 inch deep in a sand/soil/peat-moss mix in autumn resulted in bulblets by the following spring, but again, with few exceptions, leaves were not produced until the following autumn, nearly a full year after sowing. Light may also stimulate the early leaf formation observed in this experiment. A side effect of the treatment was the prevention of dormancy. As the oldest leaves on the seedlings senesced, new leaves were produced. A possible factor in the prevention of dormancy may have been the practice of removing dead leaves. It is known that senescing leaves produce ethylene, which in turn stimulates senescence in other leaves. At this time, seedlings have not been observed long enough to determine whether or not the observed inhibition of dormancy will carry through until flowering of all seedlings.

In addition to reducing generation time, part of this treatment (lifting the bulbs at each transplanting and maintaining in a warm greenhouse) may be useful to bring small offsets or tissue-culture-induced bulblets up to flowering size in a reduced period of time.

REFERENCES

Other bulbs