Tree Genetics & Genomes

, Volume 10, Issue 4, pp 1027–1043

Landscape genetics of Persian walnut (Juglans regia L.) across its Asian range

  • Paola Pollegioni
  • Keith E. Woeste
  • Francesca Chiocchini
  • Irene Olimpieri
  • Virginia Tortolano
  • Jo Clark
  • Gabriel E. Hemery
  • Sergio Mapelli
  • Maria Emilia Malvolti
Original Paper

Abstract

Persian walnut (Juglans regia L) is an economically important species cultivated worldwide for its wood and nuts. Despite the increasing interest in the development of conservation strategies for walnut germplasm, an accurate and full-scale overview of wild genetic resources of J. regia has not been conducted because natural populations are located in regions of Asia historically difficult to access. In this study, we estimated the genetic diversity and spatial genetic structure of 39 autochthonous Persian walnut populations sampled across its Asian range using 14 neutral microsatellite markers. A landscape genetic overlay approach was applied to detect the areas of current reservoirs of walnut genetic diversity in the Asian range and to evaluate the role of landscape in shaping walnut genetic diversity since the Last Glacial Maximum. Although Persian walnut has been highly manipulated by humans over the last 2,000 years, we determined that patches of high genetic diversity still exist in the Caucasus and mountains of Central Asia where J. regia might have survived after Pleistocene glaciations. We detected a clear separation of Persian walnut into four main genetic clusters centered in (1) western Kyrgyzstan, (2) western and south–central Asia, (3) east–central Uzbekistan, and (4) Xinjiang and Shandong provinces (China). Overlay of maps showed a coincidence between groups of walnut populations and potential barriers to gene flow such as the Hindu Kush, Pamir, Tien Shan, and Himalaya mountains and the Karakum, Kyzyl Kum, and Taklamakan deserts. This study claimed the relevance of the preservation of walnut genetic resources in the Asian range.

Keywords

Landscape genetics Genetic diversity Population genetic structure Asia Nuclear microsatellites Juglans regia 

Supplementary material

11295_2014_740_MOESM1_ESM.docx (57 kb)
ESM 1(DOCX 56 kb)
11295_2014_740_MOESM2_ESM.docx (1.3 mb)
ESM 2(DOCX 1335 kb)
11295_2014_740_MOESM3_ESM.docx (24 kb)
ESM 3(DOCX 23 kb)
11295_2014_740_MOESM4_ESM.docx (24 kb)
ESM 4(DOCX 23 kb)
11295_2014_740_MOESM5_ESM.docx (303 kb)
ESM 5(DOCX 303 kb)
11295_2014_740_MOESM6_ESM.docx (30 kb)
ESM 6(DOCX 30 kb)
11295_2014_740_MOESM7_ESM.docx (37 kb)
ESM 7(DOCX 37 kb)
11295_2014_740_MOESM8_ESM.docx (33 kb)
ESM 8(DOCX 33 kb)

Copyright information

© Springer-Verlag Berlin Heidelberg 2014

Authors and Affiliations

  • Paola Pollegioni
    • 1
    • 2
  • Keith E. Woeste
    • 3
  • Francesca Chiocchini
    • 1
  • Irene Olimpieri
    • 1
  • Virginia Tortolano
    • 1
  • Jo Clark
    • 4
  • Gabriel E. Hemery
    • 5
  • Sergio Mapelli
    • 6
  • Maria Emilia Malvolti
    • 1
  1. 1.CNR Institute of Agro-environmental and Forest BiologyPoranoItaly
  2. 2.Department of Forestry and Natural ResourcesPurdue UniversityWest LafayetteUSA
  3. 3.USDA Forest Service, Hardwood Tree Improvement and Regeneration Center, Department of Forestry and Natural ResourcesPurdue UniversityWest LafayetteUSA
  4. 4.Earth TrustLittle Wittenham, AbingdonUK
  5. 5.Sylva FoundationLittle WittenhamUK
  6. 6.CNR Institute of Agricultural Biology and BiotechnologyMilanItaly

Personalised recommendations