四倍体菊花脑与栽培菊种间杂交及F_1杂种的遗传表现

Interspecific Hybridization Between the Tetraploid Chrysanthemum nankingense and Ch. grandiflorum ‘Zhongshanzixing’ and the Genetic Performance of Their F_1 Hybrids

【目的】通过染色体加倍途径克服栽培菊花与二倍体野生菊种间杂交障碍,实现野生菊的优异性状或基因导入栽培菊花,拓宽菊花基因库,获得菊花新种质。【方法】以菊花脑(Chrysanthemum nankingense,二倍体)及其四倍体为父本,与栽培菊花‘钟山紫星’(Ch.grandiflorum‘Zhongshanzixing’)杂交,通过细胞学进行杂种鉴定,并对杂种F1代部分性状进行统计分析。【结果】二倍体与四倍体菊花脑的花粉活力均较高,且在母本‘钟山紫星’柱头上能正常萌发,但‘钟山紫星’与二倍体菊花脑杂交不能结实,而与四倍体菊花脑杂交结实率达3.25粒/花序。‘钟山紫星’、四倍体菊花脑及其杂种F1代体细胞染色体数分别为54、36和45,减数分裂中期Ⅰ染色体平均构型均以二价体为主,分别是27Ⅱ、1.70Ⅰ+13.23Ⅱ+0.03Ⅲ+1.90Ⅳ和5.32Ⅰ+13.84Ⅱ+2.79Ⅳ+0.16Ⅵ。杂种F1代株高、叶宽和叶柄长呈正向中亲优势,而节间长、叶形指数、花序直径、花盘直径和小花数目均呈负向中亲优势,均达到极显著水平。【结论】二倍体菊花脑通过染色体加倍途径可以有效克服其与栽培菊花间的远缘杂交障碍。

【Objective】 The interspecific hybridization barrier between cultivated chrysanthemum and diploid wild species were overcome by doubling chromosome,in order to transfer excellent traits or genes of the diploid wild species into chrysanthemum,broaden the gene pool in chrysanthemum,and achieve novel germplasm.【Method】 Artificial hybridizations were made between the diploid and tetraploid of Chrysanthemum nankingense（♂） and cultivated chrysanthemum（Ch.grandiflorum ‘Zhongshanzixing’）（♀）.Cytology analysis was used for hybrids identification and some characters of the hybrids were analyzed.【Result】 Pollen viability of the diploid and tetraploid were higher and the pollen grains could germinate on the stigma of Ch.grandiflorum ‘Zhongshanzixing’ well.But no seed was obtained in the combination between the diploid of Ch.nankingense and Ch.grandiflorum ‘Zhongshanzixing’ while a number of interspecific hybrids were obtained by crossing tetraploid Ch.nankingense with Ch.grandiflorum ‘Zhongshanzixing’.The chromosome number of Ch.grandiflorum ‘Zhongshanzixing’,tetraploid of Ch.nankingense and their hybrids were 54,36,and 45,respectively.The chromosome commonest configurations at metaphaseⅠ per pollen mother cell in Ch.grandiflorum ‘Zhongshanzixing’,tetraploid Ch.nankingense and their hybrids were 27Ⅱ,1.70Ⅰ＋13.23Ⅱ＋0.03Ⅲ＋ 1.90Ⅳ and 5.32Ⅰ＋13.84Ⅱ＋2.79Ⅳ＋0.16Ⅵ,mainly with bivalent.Plant height,leaf width,petiole length of hybrids were significantly positive in mid-parent heterosis of hybrids,while their internode length,leaf index,inflorescence diameter,floral disk diameter,and floret number were significantly negative in mid-parent heterosis.【Conclusion】 Doubling the chromosome of Ch.nankingense could overcome the distant hybridization barrier with the cultivated chrysanthemum.