红花玉兰种质资源遗传多样性初探

Genetic Diversity of Magnolia wufengensis Based on AFLP

采用AFLP分子标记对目前仅发现在湖北五峰狭域分布的红花玉兰种质资源的遗传多样性进行了研究.用10对引物对6个居群的43个个体进行了选择性扩增,共检测到623个有效位点,其中多态位点595个.结果表明:在物种水平上,红花玉兰的遗传多样性水平很高,多态位点百分率达95.51%,Nei s基因多样度(HT)为0.211 0±0.028 6;红花玉兰的遗传变异主要存在于居群内,居群间的遗传分化较小.AMOVA分析表明总变异的93.37%存在于居群内,居群间的变异只占总变异的6.63%.Nei s遗传分化系数(GST)为0.191 9,居群间基因流(Nm)2.105 5.鉴于红花玉兰总体遗传多样性水平很高,而居群数目及居群内个体数量均很少,应该对红花玉兰各居群的所有个体实施及时的就地保护,并对其生境进行保护;并在原产地营建基因保存林,营建时应加大各居群内的取样数量,使得红花玉兰较高的遗传多样性得到保存;同时积极开展异地引种栽培,使红花玉兰在观赏应用中得到切实的保护.

An analysis of diversity of Magnolia wufengensis, now only found native in Wufeng county, southwest of Hubei Province,China was carried out to assess genetic diversity using amplified fragment length polymorphism （AFLP）. A total of 623 AFLP fragments,of which 595 were polymorphic, scored on 43 samples from 6 populations and by 10 primer combinations. The results revealed that there is a high genetic diversity on species level, the percentage of polymorphic loci and Nei＇s total genetic diversity （Hr） are as high as 95.51% and 0. 211 0±0. 028 6 respectively; AMOVA analysis indicates that the most total genetic variation （93.37 %） of M. wufengensis is within populations, the differentiation among populations is only 6.63% ;the Nei＇s Gsr is 0. 191 9 and the gene flow （Nm） among populations is 2. 105 5. In consideration of the high genetic diversity and the small populations of M. wufengensis, all the individuals in each population should be protected instantly in situ conservation and the habitat should be protected properly as well. The gene conservation forest at Wufeng should be built promptly, and enough samples from each population should be selected and the high species genetic diversity should he preserved in the course of building. Ex situ introduction and cultivation which surely conserve the germplasm in the process of making green and ornament also should be taken quickly.