Genetic diversity of Persian walnut ( Juglans regia) in the cold-temperate zone of the United States and Europe

Ebrahimi, Aziz; Zarei, Abdolkarim; McKenna, James R.; Bujdosó, G.; Woeste, Keith

doi:10.1016/j.scienta.2017.03.030

Cited by 38 publications

(30 citation statements)

References 34 publications

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“…This may explain much of the reduced genetic diversity in the species today. Screens of polymorphic SSR markers in J. regia cultivated in the Midwest showed evidence of a genetic bottleneck and severely reduced genetic diversity compared to European Carpathian samples (Ebrahimi et al, 2017). A longitudinal trend of genetic variability was reported in Eurasian J. regia populations Pollegioni et al (2017).…”

Section: Juglans Genome Signature Of Selectionmentioning

confidence: 92%

“…Some Juglans traits, such as cold hardiness, have evolved over time and can now be used in selection studies (Ramos, 1997). Prevalence of cold periods and undulations in temperature in response to climate change have negatively impacted exotic Juglans species in the Midwest U.S. (Ebrahimi et al, 2017). Despite the many research studies in the literature on Juglans, none have focused on genetic mechanisms for cold hardiness.…”

Section: Introductionmentioning

confidence: 99%

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Morpho-Physiological and Genomic Evaluation of Juglans Species Reveals Regional Maladaptation to Cold Stress

et al. 2020

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Climate change may have unpredictable effects on the cold hardiness of woody species planted outside of their range of origin. Extreme undulations in temperatures may exacerbate susceptibility to cold stress, thereby interfering with productivity and ecosystem functioning. Juglans L. and their naturally occurring interspecific F1 hybrids, are distributed natively across many temperate regions, and J. regia has been extensively introduced. Cold hardiness, an environmental and genetic factor yet to be evaluated in many native and introduced Juglans species, may be a limiting factor under future climate change and following species introductions. We evaluated cold hardiness of native North American and Eastern Asian Juglans along with J. regia genotypes using field data from the Midwestern United States (Indiana), controlled freezing tests, and genome sequencing with close assessment of Juglans cold hardy genes. Many Juglans species previously screened for cold-hardiness were genotypes derived from the Midwest, California, and Europe. In 2014, despite general climate adaptation, Midwestern winter temperatures of −30 • C killed J. regia originating from California; however, naturalized Midwestern J. regia survived and displayed low damage. Hybridization of J. regia with black walnut (J. nigra) and butternut (J. cinerea) produced F1s displaying greater cold tolerance than pure J. regia. Cold hardiness and growth are variable in Midwestern J. regia compared to native Juglans, East Asian Juglans, and F1 hybrids. Phylogeny analyses revealed that J. cinerea sorted with East Asian species using the nuclear genome but with North American species using the organellar genome. Investigation of selected cold hardy genes revealed that J. regia was distinct from other species and exhibited less genetic diversity than native Juglans species Average whole genome heterozygosity and Tajima's D for cold hardy genes was low within J. regia samples and significantly higher for hybrid as well as J. nigra. We confirmed that molecular and morpho-physiological data were highly correlated and thus can be used effectively to characterize cold hardiness in Juglans species. We conclude that the genetic diversity within local J. regia populations is low and additional germplasm is needed for development of more regionally adapted J. regia varieties.

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Section: Juglans Genome Signature Of Selectionmentioning

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Morpho-Physiological and Genomic Evaluation of Juglans Species Reveals Regional Maladaptation to Cold Stress

et al. 2020

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“…Cultivars, mainly from Spain and the USA, were studied with SSR markers and data separated Spanish cultivars from those of California (RuizGarcia et al 2011). Additional studies using SSRs have focused on germplasm diversity and genetic relationships among Indian genotypes (Noor Shah et al 2016), among trees from coldtemperate areas of the USA and Europe (Ebrahimi et al 2017), and among germplasm in China (Han et al 2016;Wang et al 2016) and Romania (Pop et al 2013). Finally, two recent papers have been published.…”

Section: Peak Of Molecular Studies With Ssrs From the Late 2000smentioning

confidence: 99%

Walnut: past and future of genetic improvement

Bernard

Lheureux²,

Dirlewanger

2017

Tree Genetics & Genomes

155

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Persian or English walnut (Juglans regia L.), the walnut species cultivated for nut production, is one of the oldest food sources known. Persian walnuts, native to the mountain valleys of Central Asia, are grown worldwide in temperate areas. World production exceeds three million tons since 2012, mostly provided by China, the USA, and Iran. Despite very ancient culture of walnut species (Juglans spp.), breeding actually started in the twentieth century. Using a range of methodologies, from morphological markers to the most recent advances in genome analysis, many genetic studies of walnut have been conducted during the past 30 years, including examination of diversity, determination of relationships within or among germplasm collections and populations, phylogenetic and origin elucidation, genetic map construction, and biotic or abiotic stress investigations. The genetic improvement of walnut has undergone great evolution. The producing countries of the Middle East have widely studied morphological characteristics of walnut. The USA and France, for example, are behind important cultivar releases such as BChandler^and BFranquette.^Finally, genomics represents a major breakthrough in walnut improvement, in particular by recent sequencing of both chloroplast and nuclear genomes. This review summarizes worldwide molecular and Bomics^studies and gives an overview of the main walnut breeding programs.

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“…Many methods and techniques have been developed to advance population genetic diversity research, among which molecular tools play an important role in the management and utilization of genetic resources. Especially simple sequence repeat (SSR) molecular marker technology is an ideal method because of its simple operation, co-dominance, high resolution, polymorphism, and repeatability [22]. Many species-specific SSR markers have been developed for P. simonii [23,24] and P. tomentosa [25][26][27] by analyzing functional gene sequences, and these markers can be applied to the study of other poplar species.…”

Section: Introductionmentioning

confidence: 99%

Genetic diversity and population structure of black cottonwood (Populus deltoides) revealed using simple sequence repeat markers

Chen

Chu

Ding

et al. 2019

Preprint

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Background: Black cottonwood (Populus deltoides) is one of the keystone forest tree species, and has become the main breeding parents in poplar hybrid breeding. However, the genetic diversity and population structure of the introduced resources are not fully understood. Results: In the present study, five loci containing null alleles were excluded and 15 pairs of SSR (simple sequence repeat) primers were used to analyze the genetic diversity and population structure of 384 individuals from six provenances of P. deltoides. Ultimately, 108 alleles (Na) were detected; the expected heterozygosity (He) ranged from 0.070 to 0.905, and the average locus polymorphic information content (PIC) was 0.5354. The provenance ‘Was’ had the lowest genetic diversity, while ‘Que’, ‘Lou’, and ‘Ten’ provenances had high genetic diversity, with Shannon's information index (I) above 1.0. The mean coefficient of genetic differentiation (Fst) and gene flow (Nm) were 0.129 and 1.931 respectively. Analysis of molecular variance (AMOVA) showed that 84.88% of the genetic variation originated from individuals. Based on principal coordinate analysis (PCoA) and STRUCTURE cluster analysis, clones distributed in Mississippi River Basin were roughly classified as one group, while those distributed in the St. Lawrence River Basin and Columbia River Basin were classified as another group. The cluster analysis based on the population level showed that provenance ‘Iow’ had a smaller gene flow and higher degree of genetic differentiation compared with the other provenances, and was classified into one group. There was no significant relationship between genetic distance and geographical distance. Conclusions: P. deltoides resources have high genetic diversity and there is a moderate level of genetic differentiation among provenances. Geographical isolation and natural conditions may be the main factors causing genetic differences among individuals; however, the genetic variation among provenances has no clear correlation with their geographical locations. Clones reflecting population genetic information can be selected to build a core resource bank, which could provide effective protection and promote the scientific utilization of the P. deltoids resource, laying a solid foundation for poplar breeding.

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Genetic diversity of Persian walnut ( Juglans regia) in the cold-temperate zone of the United States and Europe

Cited by 38 publications

References 34 publications

Morpho-Physiological and Genomic Evaluation of Juglans Species Reveals Regional Maladaptation to Cold Stress

Morpho-Physiological and Genomic Evaluation of Juglans Species Reveals Regional Maladaptation to Cold Stress

Walnut: past and future of genetic improvement

Genetic diversity and population structure of black cottonwood (Populus deltoides) revealed using simple sequence repeat markers

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