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马尾松是我国南方重要的乡土树种,近30年来,受人为干扰和破坏十分严重。为了解目前广西马尾松天然遗传资源现状,评价当前种质资源收集对遗传多样性保护的有效程度,采用SSR标记对3个时期收集的广西马尾松3个优良种源进行遗传多样性研究。结果表明:现阶段,马尾松桐棉种源群体的Shannon多样性指数(I)为0.64,观测杂合度(H_o)为0.35,期望杂合度(H_e)为0.36;古蓬种源群体Shannon多样性指数(I)为0.53,Ho为0.36,He为0.32。说明广西马尾松遗传多样性仍处于较高水平。将3个种源的遗传多样性进行对比,发现桐棉种源的遗传多样性最高,古蓬种源次之,云开大山种源相对较低。群体间遗传分化系数(GST)为0.04,Wright固定指数(FST)平均值为0.026,基因流(N_m)大小为9.56,说明3个种源间不存在明显的遗传分化,群体间基因交流顺畅。将不同时期的遗传多样性进行对比分析可知:桐棉种源在18 a内Shannon多样性指数(I)下降了5%、期望杂合度(He)下降了10%;古蓬种源Shannon多样性指数下降了13%、期望杂合度(H_e)下降了14%。说明随着时间的推移,马尾松天然资源受到人为干扰愈来愈强烈,遗传多样性正逐步丧失,急需开展有针对性的保护。
Masson pine is an important native tree species in southern China. In the recent 30 years, man-made disturbance and destruction have been very serious. In order to understand the status quo of natural genetic resources of masson pine in Guangxi at present and to evaluate the effectiveness of current germplasm collection on the conservation of genetic diversity, SSR markers were used to study the genetic diversity of three provenances collected from Guangxi Masson in three periods. The results showed that the Shannon’s diversity index (I) of P. massoniana provenance population was 0.64, the observed heterozygosity (H_o) was 0.35 and the expected heterozygosity (H_e) was 0.36 at present stage. Shannon’s diversity Index (I) was 0.53, Ho was 0.36 and He was 0.32. The genetic diversity of Pinus massoniana in Guangxi is still at a high level. The genetic diversity of three provenances was compared and found that the genetic diversity of Tongmian provenance was the highest, followed by provenances of Gupeng and relatively low provenance of Yunkai Mountains. The coefficient of genetic differentiation (GST) was 0.04, the average value of Wright fixed index (FST) was 0.026, and the size of gene flow (N_m) was 9.56, indicating that there was no obvious genetic differentiation among the three provenances and the gene flow was smooth. The comparative analysis of genetic diversity at different stages showed that the Shannon’s diversity index (I) decreased 5% and the expected heterozygosity (He) decreased by 10% within 18 years. The Shannon’s diversity The index fell 13%, expected heterozygosity (H_e) decreased by 14%. It shows that with the increase of man-made natural resources, the genetic resources of Pinus massoniana are getting more and more serious, and the genetic diversity is gradually losing and the targeted protection is urgently needed.