Segregation Correlation of SSR Markers and Flower Traits in Aneuploid Tobacco

Few reports have been seen on the segregation of polyploids and on the relationship between the segregation of SSR loci and that of the morphological traits in polyploid progeny. This paper attempted to gain an insight into the segregation of the hexaploid tobacco progeny and to understand the correlation of the segregation of SSR loci with that of the flower morphological traits. The segregation was evaluated with both SSR markers and morphological traits of the flowers. Twenty pairs of SSR primers were screened and a total of 42 SSR loci were identified. Chi-square analysis showed that the segregation ratio of the SSR loci in the aneuploid progeny was between 1:1 and 2:1. Six morphological traits of flowers, including the lengths of the flower and the calyx, the widths of the calyx, the corolla tube and the corolla, and the coloring of the flower, from 180 progeny and 2 progenitor plants, were determined and Chi-square analyzed. All traits were in consistent also with a segregation ratio of 1:1 to 2:1 except the width of the calyx.

不同倍性烟草杂交获得六倍体烟草植株

以本实验室自行创制的云烟87八倍体(2n=8x=96)为母本,L-8四倍体为父本进行杂交,成功获得烟草六倍体(2n=6x=72)植株。经观察统计其花器官特征,花粉特征,并通过体外萌发及杂交试验对其育性进行初步研究。结果显示:烟草六倍体花蕾和花药明显大于云烟87四倍体×L-8四倍体杂交组合四倍体(简称四倍体杂种)后代的花蕾和花药,但花粉量较少;其花粉体外萌发率仅9.78%,明显低于四倍体杂种;六倍体花粉在六倍体及云烟87四倍体柱头上只极少量萌发并穿过花柱;以六倍体为父本,与云烟87四倍体烟草品种杂交以及六倍体自交,不能坐果;而以六倍体为母本、云烟87四倍体为父本可得到一定量种子,其单果种子数与杂种四倍体作母本、云烟87四倍体为父本时差异不大,但发芽率只有21.2%。这表明本研究中的六倍体植株作父本不育,而作母本具有一定的育性,后续研究利用中可将其用作母本。

云烟87八倍体植株的诱导及其主要生殖特征

通过不同浓度秋水仙素溶液浸泡"云烟87"四倍体无菌苗茎尖72 h,经组织培养,成功获得八倍体植株,其中以0.4%浓度秋水仙素处理检出率最高,为28.57%。与"云烟87"四倍体植株相比,八倍体植株花器官明显较大,叶片较厚、较小,节间较短。八倍体植株花粉量小,花粉大小不均一,可见超大花粉,花粉萌发率低,仅为6.45%。八倍体自交不能结实,但与四倍体烟草品种杂交均可获得大量有活力的种子,发芽率均大于65%,且与同"云烟87"四倍体杂交不能获得种子的野生烟草Nicotiana plumbaginifolia杂交也可获得有活力的种子。可见,通过秋水仙素浸泡结合组织培养获得烟草八倍体是可行的。