Genetic diversity assessment of in situ and ex situ Texas wild rice (Zizania texana) populations, an endangered plant

Wilson, Wade D.; Hutchinson, Jeffrey T.; Ostrand, Kenneth G.

doi:10.1016/j.aquabot.2015.12.005

Cited by 16 publications

(14 citation statements)

References 27 publications

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“…In the present study, Z. latifolia from the Sanjiang Plain appeared to possess low intra-population microsatellite variation (n a = 2.3, H E = 0.328) compared to Z. texana from Texas in America (n a = 11.7, H E = 0.662, Richards et al, 2007; n a = 4.4-6.3, H E = 0.53-0.65, Wilson et al, 2017) and Z. latifolia from the Yangtze River in central China (n a = 5.0, H E = 0.610; Chen et al, 2012a). A lower level of genetic variation (H E = 0.156 based on SRAP markers) was found in nine Z. latifolia populations in the same area (Fan et al, 2016).…”

Section: Clonal Diversity and Genetic Variationcontrasting

confidence: 42%

Landscape-Scale Genetic Structure of Wild Rice Zizania latifolia: The Roles of Rivers, Mountains and Fragmentation

et al. 2017

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Wild rice (Zizania latifolia) is an important genetic resource and it has important ecological functions in aquatic ecosystems as well. Here, we used landscape genetics to investigate how the landscape features, including rivers, mountains and habitat fragmentation, affect the genetic connectivity or create dispersal barriers for Z. latifolia. In this report, seventeen populations from the Sanjiang Plain and its surrounding areas were genotyped by ten microsatellite markers. A high genetic differentiation and genetic discontinuity were found among populations within each river investigated, suggesting that the rivers be not acting as corridors for dispersal. Meanwhile, genetic discontinuity was detected from different sides of the Lesser Khingan and its branch, the Qinghei Mountains, demonstrating that gene flow was blocked by the complex topography of mountains. The results that historical gene flow was much higher than the contemporary gene flow might infer that recent habitat fragmentation resulted in decreased gene flow. For all sampled Z. latifolia populations, the result of low level of genetic variation (n a = 2.3, H E = 0.328) and high genetic divergence (F ST = 0.405, D est = 0.414 and Ø pt = 0.424) was consistent with the decreased gene flow, an inbreeding system and repeated genetic bottlenecks. A conservation strategy for protecting as many populations as possible to maximize genomic representation of the species is proposed. In addition, dredging the watercourses should be carried out to improve habitat stability and to facilitate connectivity among populations.

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Section: Clonal Diversity and Genetic Variationcontrasting

confidence: 42%

Landscape-Scale Genetic Structure of Wild Rice Zizania latifolia: The Roles of Rivers, Mountains and Fragmentation

et al. 2017

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“…2017; Wilson et al. 2017). Third, genetic variation, inbreeding, and functional trait composition of different cohorts should be simultaneously compared between ex situ and wild populations to reveal the potential genetic erosion and fitness decline in both the transplanted individuals and their progenies.…”

Section: Discussionmentioning

confidence: 99%

“…Second, it is necessary to assess levels of genetic diversity and genetic composition of the ex situ populations that already exist but have not yet been assessed and to add new individuals to the collections when necessary (Kashimshetty et al 2017;Wilson et al 2017). Third, genetic variation, inbreeding, and functional trait composition of different cohorts should be simultaneously compared between ex situ and wild populations to reveal the potential genetic erosion and fitness decline in both the transplanted individuals and their progenies.…”

Section: Recommendationsmentioning

confidence: 99%

“…Due to the different species characteristics and conservation efforts, the results of empirical research on the genetic representativeness of ex situ plant populations remain mixed. Results of multiple studies show that genetic diversity of ex situ populations is lower than in natural populations (Li et al 2005;Lauterbach et al 2012;Yokogawa et al 2013;Wilson et al 2017;Chacón-Vargas et al 2020), whereas others indicate similar (Enßlin et al 2011) or even higher (LaBonte et al 2017) levels of genetic diversity in ex situ populations. Inbreeding coefficient also exhibits mixed results among ex situ conservation genetic studies (Aavik et al 2012;Yokogawa et al 2013).…”

Section: Introductionmentioning

confidence: 99%

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Meta‐analysis of genetic representativeness of plant populations under ex situ conservation in contrast to wild source populations

Wei

Jiang

2020

Conservation Biology

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Ex situ conservation is widely used to protect wild plant species from extinction. However, it remains unclear how genetic variation of ex situ plant collections reflects diversity of wild source populations. We conducted a global meta‐analysis of the genetic representativeness of ex situ populations by comparing genetic diversity (i.e., AR, allelic richness; He, expected heterozygosity; PPB, percent polymorphic bands; and SWI, Shannon–Winner index), inbreeding coefficient (FIS), and genetic differentiation between ex situ plant collections and their wild source populations. Genetic diversity (i.e., He, PPB, and SWI) was significantly lower in ex situ populations than their wild source populations, whereas genetic differentiation between ex situ and wild populations (ex‐situ‐wild FST), but not that among ex situ populations, was significantly higher than among wild populations. Outcrossing species, but not those with mixed mating system, had significantly lower genetic diversity in ex situ populations and significantly higher ex‐situ‐wild FST. When the collection size for ex situ conservation was ≥30 or 50, PPB, He, and ex‐situ‐wild FST were not significantly different between ex situ and wild populations, indicating a relatively high genetic representativeness. Collecting from the entire natural distribution range and mixing collections from different sources could significantly increase the genetic representativeness of ex situ populations. Type of ex situ conservation (i.e., planting or seed bank) had no effect on genetic representativeness. The effect size of He decreased and the effect size of ex‐situ‐wild FST increased as the duration of ex situ conservation increased. Our results suggest that current ex situ plant collections do not effectively capture the genetic variation of wild populations. Low genetic representativeness of ex situ populations was caused by both initial incomplete sampling from wild populations and genetic erosion during ex situ conservation. We emphasize that it is necessary to employ more thorough sampling strategies in future collecting efforts and to add new individuals where needed.

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“…Historically, TWR was reported residing in the upper reaches of the San Marcos River, its associated irrigation canals, and the headwaters of the river (Spring Lake) (Silveus, 1933). The current distribution of TWR is confined to the upper 5 km of the San Marcos River, with 97% of the population occurring in the upper 2.2 km (Wilson et al, 2017).…”

mentioning

confidence: 99%

Effects of Photosynthetically Active Radiation on Vegetative Growth of Texas Wild Rice and Consequences for Population Augmentation

Crawford¹,

Williamson²,

Waliczek³

et al. 2020

horts

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As urbanization and urban sprawl increases, habitat for native flora and fauna often becomes threatened. Reestablishing wildlife habitats within designed landscapes has become increasingly popular with horticultural consumers, who are becoming more aware of the benefits of using native plants and the threats of invasive species. Texas wild rice (Zizania texana Hitchc.) is a federally endangered aquatic plant known to occur only in the San Marcos River, Hays County, TX. The objective of this study was to experimentally test the impact of light availability on the vegetative growth of Texas wild rice (TWR) ex situ. The effect of photosynthetically active radiation (PAR) was tested by establishing treatment and control groups of plants in a river raceway located on the campus of Texas State University, San Marcos, TX. At the onset of the experiment, baseline growth data were collected on a random sample of 15 plants to determine starting conditions. The 75 plants within the control and treatment groups were also randomly selected. Two sequential experimental trials were designed involving the same treatment of PAR reductions with 15 TWR plants in the control group (100% of ambient PAR conditions) and 15 within each of four experimental treatment units. Treatments included a reduction in ambient light values at each of the following rates: PAR reduced by 10% (90% ambient light), 20% (80% ambient light), 40% (60% ambient light), and 80% (20% ambient light). Results of the study indicated high shade areas contained reduced areal coverage or complete lack of TWR. There was a significant decrease in both above and below ground biomass, with an 80% reduction in available PAR (20% available ambient light), and other growth parameters of TWR were negatively impacted by reductions in PAR greater than 40% (60% ambient light availability) during the short-term early establishment growth period. Therefore, light availability is a critical environmental factor that must be given consideration when deciding areas of the river to plant TWR for population augmentation.

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Genetic diversity assessment of in situ and ex situ Texas wild rice (Zizania texana) populations, an endangered plant

Cited by 16 publications

References 27 publications

Landscape-Scale Genetic Structure of Wild Rice Zizania latifolia: The Roles of Rivers, Mountains and Fragmentation

Landscape-Scale Genetic Structure of Wild Rice Zizania latifolia: The Roles of Rivers, Mountains and Fragmentation

Meta‐analysis of genetic representativeness of plant populations under ex situ conservation in contrast to wild source populations

Effects of Photosynthetically Active Radiation on Vegetative Growth of Texas Wild Rice and Consequences for Population Augmentation

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