Identification of ploidy level of Cyclamen rohlfsianum plants through flow cytometric and cytological analysis of C. rohlfsianum, C. purpurascens and their hybrid.

Summary The ploidy level of Cyclamen rohlfsianum was analyzed through the measurement of the relative fluorescent intensity (RFI) of nuclei stained with 6-diamidino-2-phenylindole (DAPI) using flow cytometry (FCM), and through the observation of mitotic and meiotic chromosomes, as compared with those of C. persicum (2 n (cid:2) 2 x (cid:2) 48, Cpe2x), C. rohlfsianum (Cro2, 2 n (cid:2) 96), C. purpurascens (2 n (cid:2) 2 x (cid:2) 34, Cpu3) and a hybrid (2 n (cid:2) 65) of C. rohlfsianum (Cro2, 2 n (cid:2) 96) (cid:3) C. purpurascens (2 n (cid:2) 2 x (cid:2) 34, Cpu3). The mean chromosome pairing at diakinesis and/or metaphase I of PMCs in Cro2, Cpu3 and their hybrid was 0.65 I (cid:4) 47.07 II (cid:4) 0.03 III (cid:4) 0.28 IV , 0.16 I (cid:4) 16.92 II and 17.00 I (cid:4) 24.00 II , respectively. These findings suggest that Cro2 is an autotetraploid (2 n (cid:2) 4 x (cid:2) 96) and the Cro2 (cid:3) Cpu3 hybrid is an allotriploid (2 n (cid:2) 3 x (cid:2) 65), produced by crossing an autotetraploid and diploid. The chromosome number of Cro3 was 2 n (cid:2) 144, equal to 1.5 times that of Cro2 (2 n (cid:2) 4 x (cid:2) 96) and the DNA content of Cro3 estimated by the RFI value corresponded to approximately 1.5 times that of Cro2, suggesting that Cro3 is an autohexaploid (2 n (cid:2) 6 x (cid:2) 144). Twelve C. rohlfsianum plants of uncertain chromosome number were classified into 3 autotetraploids and 9 autohexaploids by FCM analysis, suggesting intraspecific differentiation concerning the ploidy level in C. rohlfsianum . yet been done. In the present study, we produced a hybrid of C. rohlfsianum (cid:3) C. purpurascens by ovule culture and explored the ploidy level of C. rohlfsianum through cytological observation and FCM using C. persicum , C. rohlfsianum , C. purpurascens and the C. rohlfsianum (cid:3) C. purpurascens hybrid.

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