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林业科学 ›› 2016, Vol. 52 ›› Issue (12): 66-73.doi: 10.11707/j.1001-7488.20161208

• 论文与研究报告 • 上一篇    下一篇

木荷种子园的遗传多样性和交配系统

杨汉波, 张蕊, 周志春   

  1. 中国林业科学研究院亚热带林业研究所 浙江省林木育种技术研究重点实验室 杭州 311400
  • 收稿日期:2015-12-09 修回日期:2016-03-02 出版日期:2016-12-25 发布日期:2017-01-16
  • 通讯作者: 张蕊
  • 基金资助:
    “十二五”国家科技支撑计划课题(2012BAD01B04);浙江省农业(林业)新品种选育重大科技专项重点课题“珍贵装饰工艺用材树种形质改良与良种扩繁技术”(2016C02056-3);福建省林木种苗科技攻关五期项目木荷课题;江西省林业厅林业科技创新专项项目(201503)。

Genetic Diversity and Mating System in a Seed Orchard of Schima superba

Yang Hanbo, Zhang Rui, Zhou Zhichun   

  1. Zhejiang Provincial Key Laboratory of Tree Breeding Research Institute of Subtropical Forestry, Chinese Academy of Forestry Hangzhou 311400
  • Received:2015-12-09 Revised:2016-03-02 Online:2016-12-25 Published:2017-01-16

摘要: [目的] 研究木荷种子园遗传多样性和交配系统,揭示种子园交配机制对后代遗传多样性的影响以及亲、子代遗传多样性变化规律,为木荷种子园遗传管理提供科学依据。[方法] 以浙江省兰溪苗圃木荷种子园自由授粉子代为研究对象,运用13对SSR引物,对种子园内44个亲本及11个无性系的328个子代进行分析。[结果] 在亲本群体中检测到等位基因数(Na)5~9个不等,平均为6.286,有效等位基因数(Ne)为3.097;在子代群体中检测到5~11个等位基因(Na),平均为7.786,较亲本群体高出1.500个等位基因,子代群体的有效等位基因数(Ne)为3.751,较亲本群体高出0.654个有效等位基因。子代群体包含亲本群体所有的等位基因,此外,还检测到1~5个子代特有等位基因。亲本群体遗传多样性水平适中(He=0.632),子代群体遗传多样性(He=0.600)比亲本略有降低,观测杂合度(Ho)略高于亲本,说明子代群体中实际观察到的杂合单株占全部单株的比例均较亲本有所增加,但差异不大。子代群体Nei's基因多样度(h)和Shannon's信息指数(I)分别为0.611和1.152,均与亲本群体基本保持一致。子代群体的F值为-0.143,存在杂合子过剩。多位点交配系统分析(MLTR)结果表明:种子园异交率较高,多位点异交率(tm)为1.000,单位点异交率(ts)为0.939,亲本的近交现象不显著(tm-ts=0.061),只有较少的双亲近交事件发生;但有效花粉供体数目较少(Nep=2.3),单位点和多位点父本相关性的差值rp(s)-rp(m)=0.012>0,表明只有小部分花粉供体是近亲关系。参试11个家系间异交率不存在明显差异(tm为0.992~1.073),少数存在近交现象(31号:tm-ts=0.107;9号:tm-ts=0.117)。11个家系的父本相关性(rp)和有效花粉供体数目变化较大,分别为0.210~0.762和1.3~4.8,说明各家系的父本相关性程度不一致,其中31号最高,最低的是48号。[结论] 木荷种子园异交率高,近交现象不明显;无性系之间基因交流相对充分,遗传多样性丰富,子代能保持亲本所具有的较高的遗传多样性。

关键词: 木荷, 种子园, SSR, 遗传多样性, 异交率

Abstract: [Objective] The objective of this study was to reveal the genetic variation in parents and progenies and the effects of mating patterns on genetic diversity of the progenies. Furthermore, it also provides a scientific basis for the genetic management of the seed orchard of Schima superba.[Method] The study site is located in Lanxi nursery, Zhejiang province. A total of 44 parent trees and 328 open-pollinated progenies from 11 clones in the seed orchard of S. superba were analyzed using 13 polymorphic SSR loci.[Result] We detected 5-9 and 5-11 alleles (Na) respectively in parent and progeny population, with an average of 6.286 and 7.786, respectively. The effective number of alleles (Ne) was 3.097 and 3.751 in parent and progeny population, respectively. The Na and Ne in progeny population was 1.500 and 0.654 larger than those in the parent population, respectively. The progeny population had all alleles detected in maternal population, and one to five alleles not detected in the maternal population. The level of genetic diversity of the progeny population (He=0.600) was slightly smaller than that of the parent population (He=0.632). The observed heterozygosity (Ho) was higher in the progenies than in the parents, but not significantly different. The results indicated that the genetic uniformity and the proportion of observed heterozygosity in the progenies displayed an increase compared to the parents, but not at a significant level. The Shannon's information index (I) and Nei's genetic diversity (h) was 1.152 and 0.611 in progeny population, respectively. The value of I and h were all basically consistent with the parent population. There was an obvious heterozygosis excess in progeny population (F=-0.143). Results from multilocus mating system analysis revealed that the multilocus outcrossing rate in the seed orchard was 1.000 and the single-locus outcrossing rate (ts) was 0.939, and there was no significant inbreeding between parents (tm-ts=0.061). A slight biparental inbreeding was detected in this seed orchard. We found a small number of effective pollen donors (Nep=2.3). The D-value between multilocus correlation of paternity and singlelocus correlation of paternity (rp(s)-rp(m)) was 0.012>0, indicating that only few pollen donors were close relative relationship. The difference of correlation of paternity (rp) between the 11 families was from 0.210 to 0.762. And the number of valid pollen donor was 1.3-4.8, showed that the degree of correlation was inconsistent among paternal parents, the highest was clone 31, and the lowest was clone 48. However, outcrossing rate was not significantly different among parents (tm:0.092-1.073), and a few selfing events were detected in some families (No.31:tm-ts=0.107;No.9:tm-ts=0.117).[Conclusion] There was a high outcrossing rate, and a lower biparental inbreeding in this seed orchard. Gene exchange among clones was relatively sufficient, and genetic diversity in the progenies was kept as high as in the parents.

Key words: Schima superba, seed orchard, SSR, genetic diversity, outcrossing rate

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