Search Results

You are looking at 61 - 70 of 926 items for :

  • "genetic diversity" x
Clear All
Free access

Matthew Chappell, Carol Robacker and Tracie M. Jenkins

with evergreen azaleas, is a common plant in eastern U.S. landscapes ( Galle, 1987 ). The level of genetic diversity among species has been addressed in a previous study ( Scheiber et al., 2000 ), yet no research has described the amount of genetic

Free access

Sara Melito, Angela Fadda, Emma Rapposelli and Maurizio Mulas

( Mulas, 2012 ; Mulas et al., 2002 ). Germplasm genetic identification and characterization is an important step for the conservation and the use of plant genetic resources. DNA-based markers have been widely used to assess the genetic diversity of plant

Free access

Jie Fu, Qiaoyan Xiang, Xianbao Zeng, Mei Yang, Ying Wang and Yanling Liu

cultivars by molecular methods is necessary. In recent years, the rapid development of molecular marker technologies and DNA fingerprinting analysis has provided new techniques to assess the genetic diversity of plants and animals such as random amplified

Free access

P. Escribano, M.A. Viruel and J.I. Hormaza

/tolerance to fruit flies of the genera Ceratitis MacLeay and Anastrepha Schiner. Increasing concerns on reduced levels of genetic diversity in crop species ( Esquinas-Alcazar, 2005 ; Tanksley and McCouch, 1997 ) have led to the need to preserve as much

Free access

Laura Rodriguez-Uribe, Luz Hernandez, James P. Kilcrease, Stephanie Walker and Mary A. O’Connell

carotenoid pathways. Genetic diversity in landraces of Capsicum in Mexico ( Aguilar-Melendez et al., 2009 ; Gonzalez-Jara et al., 2011 ; Pacheco-Olvera et al., 2012 ) and in Capsicum in home gardens in Guatemala ( Guzman et al., 2005 ) has been

Full access

Mozhgan Zangeneh and Hassan Salehi

. tazetta is primarily found in Spain and northern Africa, as well as in a narrow band within China and Japan. The development of effective conservation and management strategies requires a thorough understanding of the genetic diversity and relationships

Free access

Diego Fajardo, Don R. La Bonte and Robert L. Jarret

The USDA gene bank currently maintains 668 accessions of cultivated sweetpotato and 219 accessions of related Ipomoea species. Information on the genetic diversity of the collection does not exist due to funding constraints. The development of a core collection would provide a subset of accessions that represent the genetic diversity of the main collection with a minimum of repetitiveness. The small size of the core collection would facilitate the evaluation of the accessions for economically important traits. The objective of this research is to develop a core collection of Papua New Guinea sweetpotato germplasm using the Amplified Fragment Length Polymorphisms (AFLPs) marker system. This approach to quantifying genetic diversity would later serve as a model for the development of a USDA sweetpotato germplasm core collection. The germplasm choosen for this study was collected from this crop's secondary center of genetic diversity based on its potential as a source of new traits. All genotypes were fingerprinted using four primer combinations that generated 224 markers. The molecular data was then analyzed using NTSYSpc 2.0 program to determine the relatedness of the genotypes. The molecular analysis showed a homogeneous genetic constitution. The extent of diversity among accessions was correlated with the geographic origin of the plant material.

Free access

Diego Fajardo, Don R. La Bonte and Robert L. Jarret

The USDA gene bank currently maintains 668 accessions of cultivated sweetpotato and 219 accessions of related Ipomoea species. Information on the genetic diversity of the collection does not exist due to funding constraints. The development of a core collection would provide a subset of accessions that represent the genetic diversity of the main collection with a minimum of repetitiveness. The small size of the core collection would facilitate the evaluation of the accessions for economically important traits. The objective of this research is to develop a core collection of Papua New Guinea sweetpotato germplasm using the Amplified Fragment Length Polymorphisms (AFLPs) marker system. This approach to quantifying genetic diversity would later serve as a model for the development of a USDA sweetpotato germplasm core collection. The germplasm choosen for this study was collected from this crop's secondary center of genetic diversity based on its potential as a source of new traits. All genotypes were fingerprinted using four primer combinations that generated 224 markers. The molecular data was then analyzed using NTSYSpc 2.0 program to determine the relatedness of the genotypes. The molecular analysis showed a homogeneous genetic constitution. The extent of diversity among accessions was correlated with the geographic origin of the plant material.

Free access

Fenny Dane and Yuqing Fu

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).

Free access

Hongwen Huang, Fenny Dane and J.D. Norton

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.