Variation of nuclear DNA content in interspecific Allium cepa L. × A. fistulosum L. hybrids and their successive backcross lines.

Variation of Nuclear DNA Content in Interspecific Allium cepa L.×A. fistulosum L. hybrids and Their Successive Backcross Lines Cheol-Woo Kim*, Hwa-Young Kim, Eul-Tai Lee, In-Hu Choi, and Jin-Ki Bang Mokpo Sub-Station, National Institute of Horticultural & Herbal Science, RDA, Muan 530-834, Korea Bioenergy Crop Research Center, National Institute of Crop Science, RDA, Muan 530-834, Korea Abstract : Interspecific hybrid plants between Allium cepa L. (2n=2X=16) and A. fistulosum L. (2n=2X=16)and their backcross lines were developed by artificial pollination in order to introduce new desirable characters of A, cepa to A. fistulosum. The 2C nuclear DNA content has been estimated by flow cytometry in 5 Allium fistulosum inbreed lines, 2 interspecific hybrid lines of A. cepa×A. fistulosum and 34 their backcross lines BC1F1 to BC2F2, using propidium iodide (PI) as a fluorescence dye. Estimated 2C DNA values ranged from 22.2 pg to 23.7 pg in 5 A. fistulosum inbreed lines, 37.9 pg in F1 hybrid between A. cepa and A. fistulosum, 24.3 pg to 27.3 pg in 7 backcross lines in BC1F1, 21.9 pg to 24.4 pg in 9 BC1F2, 22.9 pg to 25.1 pg in 14 BC2F1, 22.6 pg to 23.4 pg in 4 BC2F2. This study showed mean 2C nuclear DNA content of F1 hybrid was higher than their backcross progeny lines, while it was lower than female parental line, A. cepa (2C DNA=33.2 pg). Mean 2C DNA content of backcross lines, BC1F1 to BC2F2 was not significantly different but their 2C DNA contents in the more progress generation from BC1F1 to BC2F2 were reduced.