木薯有性四倍体遗传稳定性分析

Genetic Stability Analysis of Sexual Tetraploid in Cassava

木薯作为中国重要的经济作物,其优良品种的选育一直是木薯科研工作的重点,而多倍体的巨型性特点为其育种提供了新的思路,目前多倍体研究大多是体细胞加倍,有性多倍化研究起步较晚,而本课题组通过2n配子有性活体杂交,成功获得了首例木薯有性四倍体植株。为了研究木薯有性四倍体的遗传稳定性,本研究分别采用:田间的农艺性状观测(生长稳定期)、流式细胞术、叶片染色体计数、蛋白质含量测定/蛋白质聚丙烯酰胺凝胶电泳以及淀粉含量测定等方法进行鉴定。结果显示:木薯有性四倍体各株系农艺性状均保持了母株器官巨型性的多倍体特征;流式细胞仪分析显示,木薯有性四倍体各株系叶片DNA含量均为二倍体亲本(SC5)的两倍,相对应的叶片染色体数目也为二倍体亲本(SC5)的两倍,且视野中四倍体细胞所占比例均在90%以上;各株系蛋白质含量均小于二倍体对照组,且有性多倍体株系电泳谱带基本相似;在淀粉含量测定中,其各株系淀粉含量均小于对照组,且各株系之间含量波动较小。本研究结果表明木薯有性四倍体植株具有较好的遗传稳定性,对木薯多倍体品种的选育具有重要意义。

As an important cash crop in China,the breeding of improved varieties has always been the focus of cassava scientific research,and the mega-characteristics of polyploidy provide a new idea for its breeding.At present,most of the studies on polyploidy are somatic cell doubling.The research of sexual polyploidization started relatively late,but our research group successfully obtained the first cassava sexual tetraploid plant through 2 n gamete sexual in vivo hybridization.In order to investigate the genetic stability of sexual tetraploid in cassava,the identification methods of field agronomic character observation(stable growth period),flow cytometry,leaf chromosome count,protein content determination/protein polyacrylamide gelelectrophoresis and starch content determination were used in present study.The results showed that the agronomic characters of all the cassava sexual tetraploid lines maintained the polyploid characteristics of the giant organs of the mother plants;the flow cytometry analysis showed that the DNA content in the leaves of each lines of cassava sexual tetraploid was twice that of the diploid parent(SC5),the corresponding number of chromosomes in the leaves was twice that of the diploid parent(SC5),and the tetraploid cells accounted for more than 90%in the field;the protein content of each sexual tetraploid lines was lower than that of the diploid control group,and the electrophoretic bands of each sexual tetraploid lines were basically similar;in the determination of starch content,the starch content of each sexual tetraploid lines was smaller than that of the control group,and the content fluctuation between each sexual tetraploid lines was small.The results of this study indicate that cassava sexual tetraploid plants has good genetic stability,which is of great significance for the breeding of cassava polyploid varieties.