AMPHIDIPLOIDS BETWEEN CYCLAMEN-PERSICUM MILL AND CYCLAMEN-PURPURASCENS MILL INDUCED BY TREATING OVULES WITH COLCHICINE IN-VITRO AND SESQUIDIPLOIDS BETWEEN THE AMPHIDIPLOID AND THE PARENTAL SPECIES INDUCED BY CONVENTIONAL CROSSES
H. Ishizaka et J. Uematsu, AMPHIDIPLOIDS BETWEEN CYCLAMEN-PERSICUM MILL AND CYCLAMEN-PURPURASCENS MILL INDUCED BY TREATING OVULES WITH COLCHICINE IN-VITRO AND SESQUIDIPLOIDS BETWEEN THE AMPHIDIPLOID AND THE PARENTAL SPECIES INDUCED BY CONVENTIONAL CROSSES, Euphytica, 86(3), 1995, pp. 211-218
We cultured colchicine-treated hybrid ovules in vitro to produce ferti
le amphidiploids of C. persicum (2n = 2x = 48, referred to as AA) x C.
purpurascens (2n = 2x = 34, referred to as BE). Seedlings and mature
plants were obtained from the ovules without colchicine and those expo
sed to 50 mg/l colchicine for 5, 10 and 15 days, whereas they were not
obtained from the ovules exposed to 50 mg/l colchicine for 20 days an
d 500 mg/l for 5, 10, 15 and 20 days. Although 8 mature hybrids derive
d from the ovules without colchicine produced a few fertile pollen gra
ins, they failed to produce viable seeds by self-fertilization, The hy
brids had 41 somatic chromosomes. Four and 3 mature plants were derive
d from ovules exposed to 50 mg/l colchicine for 10 and 15 days, respec
tively. One each among 4 and 3 mature plants showed a high frequency o
f pollen grain fertility, produced several seeds by self-fertilization
, and had 82 somatic chromosomes which is twice the number of hybrid c
hromosomes (2n = 41, AB). These findings indicated that these plants a
re amphidiploids (2n = 82, AABB) between C. persicum and C. purpurasce
ns. Three and 2 viable seeds were derived by the conventional crosses
of diploid C. persicum x the amphidiploid and the amphidiploid x C. pu
rpurascens, respectively. Flowering plants that developed from the see
ds of diploid C. persicum x the amphidiploid were barely fertile and h
ad 65 somatic chromosomes (2n = 65, AAB), whereas those that developed
from the seeds of the amphidiploid x C. purpurascens were barely fert
ile and had 58 somatic chromosomes (2n = 58, ABB). The somatic chromos
omes indicated that these plants are probably sesquidiploids between t
he amphidiploid and either C. persicum or C. purpurascens. The intersp
ecific cross-breeding of cyclamen using the amphidiploids and the sesq
uidiploids is discussed.