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 Genetic Diversity Evaluations of Threatened Ozark and Allegheny Chinkapin Populations

HortScience ◽  
2000 ◽  
Vol 35 (4) ◽  
pp. 553D-553c
Author(s):  
Fenny Dane ◽  
Yuqing Fu
Keyword(s):  
Genetic Diversity ◽  
Gulf Of Mexico ◽  
Cryphonectria Parasitica ◽  
Genetic Identity ◽  
Conservation Strategies ◽  
Chestnut Blight ◽  
Ozark Mountains ◽  
Unique Allele ◽  
Geographic Populations

Chestnut blight, caused by the Asian fungus Cryphonectria parasitica, has severely affected chinkapin populations (Castanea pumila), especially those limited to the Ozark mountains (var. ozarkensis). Genetic diversity within and between geographic populations of the Allegheny (var. pumila) and Ozark chinkapin populations was evaluated for development of appropriate conservation strategies. Nuts or dormant buds collected from populations along the range of the species were analyzed using allozymes. A unique allele was detected in populations along the gulf of Mexico. Significant differences in genetic diversity were observed among Allegheny populations, but not among Ozark populations. High levels of genetic identity were detected among widely distributed populations from Florida to Virginia (Allegheny chinkapin populations) and Arkansas (Ozark chinkapin populations).

scholarly journals Evaluation of the Genetic Diversity Castanea pumila var. ozarkensis through Isozyme Analysis and DNA Amplification Fingerprinting

HortScience ◽  
1997 ◽  
Vol 32 (3) ◽  
pp. 441A-441
Author(s):  
Fenny Dane ◽  
Hongwen Huang
Keyword(s):  
Genetic Diversity ◽  
Rapd Markers ◽  
Dna Amplification ◽  
Allele Frequencies ◽  
National Forest ◽  
Germplasm Enhancement ◽  
Genetic Diversity And Structure ◽  
Geographic Populations ◽  
Natural Range ◽  
Conservation Plan

The genetic diversity within and between four geographic populations of the Ozark chinkapin was evaluated and partitioned in order to gain an understanding of the overall genetic diversity and structure of this species, which will be instrumental for its preservation and germplasm enhancement. Nuts of chinkapin trees along the natural range of the species in the Sylamore Ranger District of the Ozark National Forest in Arkansas were collected and evaluated with isozyme and RAPD markers scattered across the genome. Allozyme differences were detected among the geographic populations. Allele frequencies will be determined and subjected to genetic diversity statistics. A conservation plan will be recommended.

Movement of cytoplasmic hypovirulence agents in chestnut blight cankers

1992 ◽  
Vol 70 (3) ◽  
pp. 557-561 ◽  
Author(s):  
L. Shain ◽  
J. B. Miller
Keyword(s):  
Biological Control ◽  
Key Words ◽  
Cryphonectria Parasitica ◽  
Castanea Dentata ◽  
American Chestnut ◽  
Chestnut Blight ◽  
Typical Morphology ◽  
Natural Range ◽  
Hypovirulent Strain ◽  
Endothia Parasitica

Chestnut blight cankers, initiated with virulent methionine auxotrophic strains of Cryphonectria parasitica, were challenged by placing one or two discs of agar and mycelium of prototrophic hypovirulent strains at their base. Movement of hypovirulence agents was confirmed by recovery of an isolate that exhibited the typical morphology of the introduced hypovirulent strain on media with methionine but little or no growth on media without methionine. Cultures from bark showed that the hypovirulent agent moved through mycelium around the circumference of cankers within 3 weeks when the virulent and challenging hypovirulent were vegetatively compatible. Conversion of the mycelium in the canker interior proceeded more slowly. Conversion of mycelium also was delayed, but eventually occurred, when virulent and hypovirulent inocula differed in vegetative compatibility. Conidia, however, continued to yield virulent, methionine-requiring cultures up to 65 weeks after challenge, even though underlying bark frequently yielded hypovirulent, methionine-requiring cultures. This disinclination of hypovirulent agents to enter the asexual apparatus in cankers may contribute substantially to the observed ineffective dissemination of hypovirulence in the natural range of American chestnut. Exploitation of those hypovirulent agents that can enter conidia in cankers may enhance the biological control of chestnut blight by hypovirulence. Key words: biological control, Cryphonectria parasitica, Endothia parasitica, Castanea dentata.

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 Genetic diversity of Cryphonectria parasitica causing chestnut blight in South Tyrol (northern Italy)

2022 ◽  
Author(s):  
Farooq Ahmad ◽  
Sanja Baric
Keyword(s):  
Genetic Diversity ◽  
Diversity Index ◽  
Castanea Sativa ◽  
Cryphonectria Parasitica ◽  
Northern Italy ◽  
Chestnut Blight ◽  
Type Locus ◽  
South Tyrol ◽  
Its Sequence Analysis ◽  
Hyphal Anastomosis

AbstractEuropean chestnut (Castanea sativa) is threatened by the invasive fungus Cryphonectria parasitica, which causes chestnut blight. The virulence of the fungus can be reduced by a group of mycoviruses that can spread among vegetatively compatible strains through hyphal anastomosis. Hypovirulent isolates are used as biocontrol agents, but their efficiency can be diminished by restricted hyphal anastomosis if the variability of vegetative compatibility (vc) types in a population is high. Sexual reproduction could increase the vc type diversity and further complicate biocontrol in a region. Therefore, knowledge of genetic diversity of C. parasitica is important to assess the effectiveness of a biological control program. The present study was performed in the Autonomous Province of Bozen-Bolzano (South Tyrol) in northern Italy, where chestnut cultivation provides an additional income to farmers. The genetic characterization of C. parasitica isolates from 35 chestnut stands and one forest population in different districts of South Tyrol was performed based on the analysis of vegetative incompatibility loci, the mating type locus, and the internal transcribed spacer (ITS) region. In this study, a total of 23 different vc types were found all over South Tyrol with a Shannon diversity index of 1.86. EU-2, EU-1, and EU-13 were the most widespread vc types comprising 51%, 13%, and 9% of the fungal isolates, respectively. Both mating types were present in the region with a ratio close to 1:1. Three different haplotypes were identified based on ITS sequence analysis, which pointed to two introduction events of the fungus to the region and allowed placing C. parasitica from South Tyrol into a larger phylogeographic context.

scholarly journals EVALUATION OF THE GENETIC DIVERSITY OF THE AMERICAN CHESTNUT

HortScience ◽  
1996 ◽  
Vol 31 (5) ◽  
pp. 750d-750
Author(s):  
Hongwen Huang ◽  
Fenny Dane ◽  
J.D. Norton
Keyword(s):  
Genetic Diversity ◽  
New York ◽  
North Carolina ◽  
Plant Material ◽  
Rapd Markers ◽  
American Chestnut ◽  
Shoot Buds ◽  
Chestnut Tree ◽  
Geographic Populations ◽  
Isozyme Loci

The genetic diversity within and between geographic populations of the American chestnut tree was evaluated with allozyme and RAPD markers. Winter dormant or mature shoot buds from American chestnut trees collected in Alabama, Georgia, North Carolina, Virginia, Pennsylvania, Ohio, Michigan, and Connecticut were used for isozyme assays. Genetic diversity statistics calculated for 20 isozyme loci indicated that the highest level of heterozygosity was detected in the Alabama and Connecticut populations, the lowest level in the Great Smoky Mountain populations. RAPD analyses were conducted on American chestnut plant material. The best results were obtained with seed tissue. Seed from New York, Virginia, and Pennsylvania populations and buds from Alabama and Georgia populations were evaluated for RAPD markers scattered throughout the chestnut genome.

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