Next Article in Journal
Biology and Management of Vulpia myuros—An Emerging Weed Problem in No-Till Cropping Systems in Europe
Next Article in Special Issue
The Role of Vegetable Genetic Resources in Nutrition Security and Vegetable Breeding
Previous Article in Journal
Transcriptome and Network Analyses of Heterostyly in Turnera subulata Provide Mechanistic Insights: Are S-Loci a Red-Light for Pistil Elongation?
Previous Article in Special Issue
Genetic Diversity, Population Structure and Marker-Trait Association for 100-Seed Weight in International Safflower Panel Using SilicoDArT Marker Information
Open AccessArticle

Genetic Structure of Wild Germplasm of Macadamia: Species Assignment, Diversity and Phylogeographic Relationships

Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, Brisbane, QLD 4072, Australia
*
Author to whom correspondence should be addressed.
Plants 2020, 9(6), 714; https://doi.org/10.3390/plants9060714
Received: 15 May 2020 / Revised: 29 May 2020 / Accepted: 30 May 2020 / Published: 3 June 2020
(This article belongs to the Special Issue Plant Biodiversity and Genetic Resources)
Macadamia is an Australian native rainforest tree that has been domesticated and traded internationally for its premium nuts. Common cultivars rely upon a limited gene pool that has exploited only two of the four species. Introducing a more diverse germplasm will broaden the genetic base for future crop improvement and better adaptation for changing environments. This study investigated the genetic structure of 302 accessions of wild germplasm using 2872 SNP and 8415 silicoDArT markers. Structure analysis and principal coordinate analysis (PCoA) assigned the 302 accessions into four distinct groups: (i) Macadamia integrifolia, (ii) M. tetraphylla, and (iii) M. jansenii and M. ternifolia, and (iv) admixtures or hybrids. Assignment of the four species matched well with previous characterisations, except for one M. integrifolia and four M. tetraphylla accessions. Using SNP markers, 94 previously unidentified accessions were assigned into the four distinct groups. Finally, 287 accessions were identified as pure examples of one of the four species and 15 as hybrids of M. integrifolia and M. tetraphylla. The admixed accessions showed the highest genetic diversity followed by M. integrifolia, while M. ternifolia and M. jansenii accessions were the least diverse. Mantel test analysis showed a significant correlation between genetic and geographic distance for M. integrifolia (r = 0.51, p = 0.05) and a positive but not significant correlation for M. tetraphylla (r = 0.45, p = 0.06). This study provides a population genetics overview of macadamia germplasm as a background for a conservation strategy and provides directions for future macadamia breeding. View Full-Text
Keywords: genetic diversity; DArT markers; macadamia; dendrogram; principal coordinate analysis; population structure; population genetics; wild species genetic diversity; DArT markers; macadamia; dendrogram; principal coordinate analysis; population structure; population genetics; wild species
Show Figures

Figure 1

MDPI and ACS Style

Mai, T.; Alam, M.; Hardner, C.; Henry, R.; Topp, B. Genetic Structure of Wild Germplasm of Macadamia: Species Assignment, Diversity and Phylogeographic Relationships. Plants 2020, 9, 714.

Show more citation formats Show less citations formats
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Search more from Scilit
 
Search
Back to TopTop