Genetic assessment of three Fagaceae species in forest restoration trials

Patcharawadee Thongkumkoon; Siriwadee Chomdej; Jatupol Kampuansai; Waranee Pradit; Pimubon Waikham; Stephen Elliott; Sutthathorn Chairuangsri; Dia Panitnard Shannon; Prasit Wangpakapattanawong; Aizhong Liu

doi:10.7717/peerj.6958

Genetic assessment of three Fagaceae species in forest restoration trials

PeerJ. 2019 May 28:7:e6958. doi: 10.7717/peerj.6958. eCollection 2019.

Authors

Affiliations

¹ Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai, Thailand.
² Environmental Science Research Center, Faculty of Science, Chiang Mai University, Chiang Mai, Thailand.
³ Forest Restoration Research Unit, Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai, Thailand.
⁴ Key Laboratory for Forest Resource Conservation and Utilization in the Southwest Mountains of China (Ministry of Education), Southwest Forestry University, Kunming, China.

Abstract

Restoring isolated patches of forest ecosystems in degraded landscapes could potentially lead to genetic loss and inbreeding. Therefore, this study determined the occurrence of genetic diversity among the tree species Castanopsis tribuloides, C. calathiformis, and Lithocarpus polystachyus all of which were proven previously to be effective native tree species in the restoration of upland evergreen forests in northern Thailand when using the seed sample collection method. We tested our hypothesis as to whether the genetic diversity of a plant population that had been planted from the seeds of 4-6 adult trees would be lower and whether incidences of fixation index (Fis) would be higher among the second generation seedlings of these three Fagaceae species in isolated forest restoration trial plots. Microsatellite primers were selected from the entire genome sequence of C. tribuloides and the genetic sequences of C. tribuloides, L. polystachyus, and C. calathiformis were analyzed. Our results indicated a high degree of genetic diversity (He) in C. tribuloides (0.736) and C. calathiformis (0.481); however, a low level of genetic diversity was observed in L. polystachyus (0.281) within the restored forest. The fixation index for the second generation of L. polystachyus and C. calathiformis in the restored forest showed evidence of inbreeding. These results imply the efficiency of the seed sample collection method and verify that it does not reduce the level of genetic diversity in C. tribuloides and C. calathiformis. However, it may result in incidences of an inbreeding phenomena, suggesting the need to increase the number of adult trees used at the seed collection stage.

Keywords: Chiang Mai; Forest restoration; Framework tree species; Genetic diversity; Microsatellite markers.

Grants and funding

This research was supported by the Multidisciplinary Science Research Centre (MRSC) ((1) 1/2558) from Chiang Mai University and the National Research Council of Thailand (2559A10432016) and also partially by Chiang Mai University. There was no additional external funding received for this study. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.