scholarly journals Analysis of Environment-Marker Associations in American Chestnut

Forests ◽  
2018 ◽  
Vol 9 (11) ◽  
pp. 695 ◽  
Author(s):  
Markus Müller ◽  
C. Nelson ◽  
Oliver Gailing
Keyword(s):  
Genetic Variation ◽  
Environmental Conditions ◽  
Cryphonectria Parasitica ◽  
American Chestnut ◽  
Distribution Area ◽  
Chestnut Blight ◽  
Outlier Analysis ◽  
Adaptive Genetic Variation ◽  
Outlier Loci ◽  
Adaptive Processes

American chestnut (Castanea dentata Borkh.) was a dominant tree species in its native range in eastern North America until the accidentally introduced fungus Cryphonectria parasitica (Murr.) Barr, that causes chestnut blight, led to a collapse of the species. Different approaches (e.g., genetic engineering or conventional breeding) are being used to fight against chestnut blight and to reintroduce the species with resistant planting stock. Because of large climatic differences within the distribution area of American chestnut, successful reintroduction of the species requires knowledge and consideration of local adaptation to the prevailing environmental conditions. Previous studies revealed clear patterns of genetic diversity along the northeast-southwest axis of the Appalachian Mountains, but less is known about the distribution of potentially adaptive genetic variation within the distribution area of this species. In this study, we investigated neutral and potentially adaptive genetic variation in nine American chestnut populations collected from sites with different environmental conditions. In total, 272 individuals were genotyped with 24 microsatellite (i.e., simple sequence repeat (SSR)) markers (seven genomic SSRs and 17 EST-SSRs). An FST-outlier analysis revealed five outlier loci. The same loci, as well as five additional ones, were significantly associated with environmental variables of the population sites in an environmental association analysis. Four of these loci are of particular interest, since they were significant in both methods, and they were associated with environmental variation, but not with geographic variation. Hence, these loci might be involved in (temperature-related) adaptive processes in American chestnut. This work aims to help understanding the genetic basis of adaptation in C. dentata, and therefore the selection of suitable provenances for further breeding efforts.

scholarly journals Resistance toPhytophthora cinnamomiin American Chestnut (Castanea dentata) Backcross Populations that Descended from Two Chinese Chestnut (Castanea mollissima) Sources of Resistance

Plant Disease ◽  
2019 ◽  
Vol 103 (7) ◽  
pp. 1631-1641 ◽  
Author(s):  
Jared W. Westbrook ◽  
Joseph B. James ◽  
Paul H. Sisco ◽  
John Frampton ◽  
Sunny Lucas ◽  
...  
Keyword(s):  
Phytophthora Cinnamomi ◽  
Seedling Survival ◽  
Cryphonectria Parasitica ◽  
Castanea Dentata ◽  
American Chestnut ◽  
Chestnut Blight ◽  
Sources Of Resistance ◽  
Backcross Population ◽  
Chinese Chestnut ◽  
Root Health

Restoration of American chestnut (Castanea dentata) depends on combining resistance to both the chestnut blight fungus (Cryphonectria parasitica) and Phytophthora cinnamomi, which causes Phytophthora root rot, in a diverse population of C. dentata. Over a 14-year period (2004 to 2017), survival and root health of American chestnut backcross seedlings after inoculation with P. cinnamomi were compared among 28 BC3, 66 BC4, and 389 BC3F3families that descended from two BC1trees (Clapper and Graves) with different Chinese chestnut grandparents. The 5% most resistant Graves BC3F3families survived P. cinnamomi infection at rates of 75 to 100% but had mean root health scores that were intermediate between resistant Chinese chestnut and susceptible American chestnut families. Within Graves BC3F3families, seedling survival was greater than survival of Graves BC3and BC4families and was not genetically correlated with chestnut blight canker severity. Only low to intermediate resistance to P. cinnamomi was detected among backcross descendants from the Clapper tree. Results suggest that major-effect resistance alleles were inherited by descendants from the Graves tree, that intercrossing backcross trees enhances progeny resistance to P. cinnamomi, and that alleles for resistance to P. cinnamomi and C. parasitica are not linked. To combine resistance to both C. parasitica and P. cinnamomi, a diverse Graves backcross population will be screened for resistance to P. cinnamomi, survivors bred with trees selected for resistance to C. parasitica, and progeny selected for resistance to both pathogens will be intercrossed.

scholarly journals 065 Genetic Diversity of the Allegheny Chinkapin (Castanea pumila var. pumila)

HortScience ◽  
1999 ◽  
Vol 34 (3) ◽  
pp. 452C-452
Author(s):  
Fenny Dane
Keyword(s):  
Genetic Diversity ◽  
Rapd Marker ◽  
Cryphonectria Parasitica ◽  
American Chestnut ◽  
Disease Spread ◽  
Conservation Strategies ◽  
Chestnut Blight ◽  
Geographic Populations ◽  
Natural Range ◽  
Conservation Plan

American species in the genus Castanea are susceptible to chestnut blight, caused by the Asian fungus Cryphonectria parasitica. This disease spread throughout the natural range of the American chestnut and reduced the species from a timber and nut producing tree to an understory shrub. The lesser known member of the genus, the chinkapin, has also been affected by this disease and a conservation plan is needed. Genetic diversity within and between geographic populations of the Allegheny chinkapin was evaluated to provide baseline genetic information pertinent to conservation of the species. Nuts of Allegheny chinkapin trees from populations in Mississippi, Florida, Alabama, Virginia, and Ohio were collected and evaluated for isozyme and RAPD marker polymorphism. The genetic diversity of these populations will be compared with that of Ozark chinkapin and American chestnut populations. Conservation strategies will be discussed.

Genetic Diversity of Castanea pulia var. ozarkensis

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 526e-527
Author(s):  
Fenny Dane ◽  
Shona Harrison ◽  
Hongwen Huang
Keyword(s):  
Genetic Diversity ◽  
Cryphonectria Parasitica ◽  
American Chestnut ◽  
Chestnut Blight ◽  
Ozark Highlands ◽  
The Past ◽  
Geographic Populations ◽  
Natural Range ◽  
Rapd Polymorphism ◽  
Taxonomic Studies

The genus Castanea includes several species, some of which, like the American chestnut (C. dentata) and chinkapin (C. pumila), are susceptible to chestnut blight, caused by the Asian fungus Cryphonectria parasitica. Blight spread throughout the natural range of the American chestnut, destroying several billion trees within the past 50 years. Although the plight of the American chestnut is well-known, the chinkapin has been neglected. Taxonomic studies indicated two varieties, the Ozark chinkapin, var. ozarkensis, limited to the Ozark Highlands of Arkansas, Missouri, and Oklahoma, and the Allegheny chinkapin, var. pumila, found from New Jersey to Florida and Texas. The genetic diversity within and between 11 geographic populations of the Ozark chinkapin was evaluated to provide baseline genetic information pertinent to the conservation and restoration of this species. Nuts or dormant buds of chinkapin trees were evaluated for isozyme and RAPD polymorphism. The genetic variability of the Ozark chinkapin populations was relatively high when compared to the American chestnut, and most of the diversity resides within the populations. Conservation considerations for restoration of the Ozark chinkapin will be discussed.

scholarly journals Environmental niche and demographic modeling of American chestnut near its southwestern range limit

2021 ◽  
Author(s):  
Robert G. Laport ◽  
Zoe S. Brookover ◽  
Brian D. Christman ◽  
Julienne Ng ◽  
Kevin Philley ◽  
...  
Keyword(s):  
Forest Canopy ◽  
Canopy Cover ◽  
Cryphonectria Parasitica ◽  
American Chestnut ◽  
Chestnut Blight ◽  
Suitable Habitat ◽  
Negative Consequences ◽  
Range Limit ◽  
Environmental Niche ◽  
Historical Range

The inadvertent introduction and rapid spread of chestnut blight (caused by Cryphonectria parasitica (Murr.) Barr) in the early 20th century resulted in the demise of American chestnut (Castanea dentata (Marsh.) Borkh.; Fagaceae) as a major component of forest canopies and had negative impacts on eastern forest communities. Research efforts over the last century have documented the persistence of occasional trees and root crown/stump sprouts throughout much of the historic range of the species providing the basis for ongoing breeding of blight-resistant stock and restoration efforts. Unfortunately, it remains unclear how much of the historic range remains climatically suitable for remnant trees that may harbor unique genetic variation for successful reintroduction efforts. Here we investigate whether the southwestern portion of the historical range remains environmentally suitable for undiscovered remnant populations of C. dentata using environmental niche modeling. We also use stage-structured matrix projection models to investigate the potential demographic future of C. dentata in W Tennessee, N Mississippi, SW Kentucky, and NW Alabama based upon observations of American chestnut in these areas over the last several decades. We found that suitable habitat associated with higher elevations and areas of high forest canopy cover occurs throughout much of southwestern portion of the historical range and that populations of American chestnut in these areas are predicted to drastically decline over the next ~100-200 years without conservation interventions to mitigate the negative consequences of chestnut blight.

Niche contraction of American chestnut in response to chestnut blight

2012 ◽  
Vol 42 (3) ◽  
pp. 614-620 ◽  
Author(s):  
Katie L. Burke
Keyword(s):  
Survival Rate ◽  
Soil Chemistry ◽  
Native Species ◽  
Cryphonectria Parasitica ◽  
American Chestnut ◽  
Forest Composition ◽  
Chestnut Blight ◽  
Population Declines ◽  
Realized Niche ◽  
Invasive Pathogens

Invasive pathogens can cause native population declines and change native species distributions, but the spatial limitations posed by disease are rarely explored. This study explored spatiotemporal variation in American chestnut ( Castanea dentata (Marsh.) Borkh.) survival over an 80-year period in response to the introduction of an invasive pathogen, chestnut blight ( Cryphonectria parasitica (Murrill) Barr), and identified changes in its current realized niche compared with its original niche. A study area in southwestern Virginia, USA, sampled historically for chestnut abundance before blight invasion, was resampled and measured for topography, soil chemistry, and forest composition. Pre-blight chestnut abundance was not significantly correlated to current chestnut abundance, suggesting that chestnut survival rate was not constant across stands. Results indicated that chestnut’s niche has shifted toward dry, high disturbance sites on southern- to western-facing slopes. This study provides evidence that chestnut is being constrained to a portion of its former niche following chestnut blight introduction because of spatial heterogeneity in survival rate.

Diversity of Cryphonectria parasitica in callused chestnut blight cankers on European and American chestnut

2019 ◽  
Vol 49 (6) ◽  
pp. e12566 ◽  
Author(s):  
Marin Ježić ◽  
Matthew Kolp ◽  
Simone Prospero ◽  
Kiril Sotirovski ◽  
Mark Double ◽  
...  
Keyword(s):  
Cryphonectria Parasitica ◽  
American Chestnut ◽  
Chestnut Blight

Castanea mollissima (hairy chestnut).

2021 ◽  
Author(s):  
Andrew Praciak
Keyword(s):  
Environmental Conditions ◽  
Rural Areas ◽  
Large Scale ◽  
Cryphonectria Parasitica ◽  
Hubei Province ◽  
Shandong Province ◽  
Chestnut Blight ◽  
The Usa ◽  
Nut Production ◽  
Serious Disease

Abstract C. mollissima has been cultivated for its nuts by the Chinese for at least 2500 years. The tree grows under a wide variety of environmental conditions, is drought- and flood-tolerant, and is very resistant to chestnut blight (Cryphonectria parasitica), which is a serious disease of Castanea species. In recent years, Chinese chestnut has been planted on a large scale in rural areas of China and on a smaller scale in the USA (Wallace, 1995), where Warmund (2011) considered it to have potential as a niche crop in the central states. In 1995, approximately 245,000 t of nuts were produced in China, of which 51,000 t came from Shandong Province and 29,000 t from Hubei Province. Overall, mean nut production in China increased from 225 kg/ha during the 1980s to 335 kg/ha in the 1990s, with yields of up to 1500 kg/ha being recorded widely (Zheng, 1985; Gao, 1997).

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