苦荞二倍体及其同源四倍体减数分裂过程的稳定性与花粉育性

Stability of Meiosis Process and Pollen Fertility of Diploid and Tetraploid Tartary Buckwheat

【目的】探明苦荞二倍体及其同源四倍体苦荞花粉母细胞减数分裂过程的稳定性与花粉育性,为苦荞多倍体育种提供参考。【方法】观察和统计八宿苦荞、WN047、WN090、武岗苦荞、WN065、川荞1号、二季早、黔威1号、晋苦2号、六荞1号、KP9920和黔威2号12个苦荞二倍体和苦荞四倍体花粉母细胞减数分裂过程中期I(MI时期)染色体配对构型、末期Ⅱ(TⅡ时期)的细胞异常程度及花粉粒败育性指标,分析比较二倍体和苦荞四倍体差异性。【结果】12个苦荞二倍体染色体配对构型主要为2n=2x=8II,占比95.42%,无双核仁;同源四倍体染色体构型多数为2n=4x=8IV,占比79.05%,有双核仁(占比18.6%)。12个苦荞二倍体在TⅡ期异常细胞频率平均为4.34%,细胞平均微核数为0.0434个,不同材料间差异不显著;同源四倍体异常细胞频率平均为24.09%,细胞平均微核数平均0.4949,不同材料间存在显著(P<0.05)或极显著(P<0.01)差异。12个苦荞二倍体花粉败育率平均9.54%,不同材料间存在显著(P<0.05)或极显著(P<0.01)差异;同源四倍体花粉败育率平均18.70%,不同材料间存在显著(P<0.05)或极显著(P<0.01)差异。苦荞四倍体细胞平均微核数及花粉粒败育率与苦荞二倍体均有极显著差异(P<0.01)。【结论】苦荞同源四倍体比二倍体具更复杂的染色体配对构型,苦荞四倍体在TⅡ时期的细胞异常性及花粉败育率均极显著高于二倍体,是导致苦荞四倍体比二倍体遗传稳定性差的主因。

【Objective】The stability of pollen mother cells in meiosis and pollen fertility of diploid and tetraploid tartary buckwheat were investigated to provide a reference for breeding of polyploid tartary buckwheat.【Method】The MI chromosome pairing configuration,the cell abnormal degree at TⅡstage and the pollen grain abortion indexes during the meiosis process of diploid and tetraploid pollen mother cells of 12 tartary buckwheats(Basu tartary buckwheat,WN047,WN090,Wugang tartary buckwheat,WN065,Chuanqiao 1,Erjizao,Qianwei 1,Jinku 2,Liuqiao 1,KP9920 and Qianwei 2)were observed and counted to compare and analyze the differences between diploid and tetraploid.【Result】The diploid chromosome pairing configuration of 12 tartary buckwheats was mainly 2n=2x=8II,accounting for 95.42%,without amphinucleolus;The tetraploid chromosome configuration was 4n=4x=8IV mostly,accounting for 79.05%,with amphinucleolus(accounting for 18.6%).The average frequency of abnormal cells in the TⅡphase of diploid in 12 tartary buckwheats was 4.34%,and the average micronuclei number in cell was 0.0434,and there was no significant difference among different materials;The average frequency of abnormal cells of tetraploid in 12 tartary buckwheats was 24.09%,and the average micronuclei number in cell was 0.4949,and there was a significant(P<0.05)or extremely significant(P<0.01)difference among different materials.The average pollen abortion rate of diploid in 12 tartary buckwheats was 9.54%,and there had a significant(P<0.05)or extremely significant(P<0.01)differences among different materials.The average pollen abortion rate of tetraploid in 12 tartary buckwheats was 18.70%,and there had a significant(P<0.05)or extremely significant(P<0.01)differences among different materials.There was also a very significant difference(P<0.01)in the average micronuclei number in cell and pollen abortion rate between tetraploid and diploid.【Conclusion】Tetraploid had more complex chromosome pairing configurations than diploid tartary buckwheat varieties.The cell abnormalities of tetraploid tartary buckwheat during the TⅡphase and pollen abortion rate were very significantly higher than that of diploid,which were the main reasons for the poor genetic stability of tetraploid tartary buckwheat varieties compared to diploid tartary buckwheat varieties.