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

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.