Y. Niimi et al., PRODUCTION OF INTERSPECIFIC HYBRIDS BETWEEN LILIUM-REGALE AND LILIUM-RUBELLUM VIA OVULE CULTURE, Engei Gakkai Zasshi, 64(4), 1996, pp. 919-925
Lilium regale and L. rubellum were crossed reciprocally to introduce e
conomically and horticulturally desirable traits of L. regale, such as
vigorous growth and disease resistance, into L. rubellum. 1. In L. re
gale xL. rubellum, seeds containing an embryo were obtained with a low
frequency (3.3 %) by stigmatic pollination at anthesis, but they did
not germinate in soil or in vitro. Seedlings were successfully obtaine
d with frequencies of 5.3 to 6.7 % by applying ovule culture 30 to 60
days after pollination. 2. In L. rubellum xL. regale, the growth of po
llen tubes was inhibited in the style after stigmatic pollination at a
nthesis; hence, no ovule with an embryo was obtained. Growth of pollen
tubes was promoted by stigmatic pollination when the pollination was
done 2 to 5 days after anthesis. Embryos definitely formed if stigmati
c pollination was carried out 5 days after anthesis, but they could no
t be rescued even when ovule culture was utilized. Cut-style pollinati
on had no effect on production of ovules with an embryo. 3. Hybridity
of seedlings resulted from L. regale xL. rubellum was confirmed by nuc
lear rDNA analysis. All of the hybrid plants analyzed were diploid wit
h 2n = 24 chromosomes and showed pollen fertilities of below 3 %. Flow
er color of the hybrids was light pink. A single hybrid clone produced
a double flower.