to believe that SSR loci isolated from two species within the big-bracted group might transfer to other Cornus species in all four of the major clades. The ability to transfer SSRs from C. florida and C. kousa to other Cornus species will play
Phillip A. Wadl, Xinwang Wang, John K. Moulton, Stan C. Hokanson, John A. Skinner, Timothy A. Rinehart, Sandra M. Reed, Vincent R. Pantalone and Robert N. Trigiano
Phillip A. Wadl, Xinwang Wang, Andrew N. Trigiano, John A. Skinner, Mark T. Windham, Robert N. Trigiano, Timothy A. Rinehart, Sandra M. Reed and Vincent R. Pantalone
, 2001 ). Two of these species, C. florida and C. kousa , are the most popular in the ornamental horticulture industry, although other species such as C. nuttallii , C. angustata , C. mas , and C. sericea are often used in landscapes. With over
Margaret T. Mmbaga, and Roger J. Sauvé,
Cloud’ ( Mmbaga and Sauvé, 2004b ). However, most Japanese dogwood ( C. kousa ) cultivars and most Japanese interspecific hybrids (C. kousa × C. florida) are resistant ( Mmbaga and Sauvé, 2004b ). Current disease management practices for this disease
Kimberly Shearer and Thomas G. Ranney
, C. hongkongensis × C. florida , C. elliptica × C. florida , and C. ×rutgersensis ( Table 2 ). In some cases, interspecific hybrids within subgenus Syncarpea could also be confirmed, including C. capitata × C. kousa and C. kousa × C. elliptica
John H. Culpepper, Luis A. Sayavedra-Soto, Brant J. Bassam and Peter M. Gresshoff
Several horticulturally important members of the genus Cornus were characterized at the DNA level to identify genotypes. Random genomic DNA fragments from Cornus florida L. `Barton' were cloned into pBR322 and λ Gem-11 and used to search for restriction fragment length polymorphisms (RFLPs) among C. sericea L., C. kousa Hance., and four cultivars of C. florida: `Barton', `Cherokee Princess', `Cloud 9', and `Mary Ellen'. Total DNA from these genotypes was restricted with several endonucleases (of which BamHI, EcoRI, and HindIII were used to search for RFLPs), vacuum-blotted onto nylon membranes, and probed with the C. florida `Barton' DNA clones. RFLPs were common among the Cornus species sericea, kousa, and florida, suggesting considerable DNA sequence divergence at the species level. RFLPs were less common among the cultivars of C. florida. These cultivars were selected from a narrow geographical area in North America from nursery-grown trees and exhibit much less DNA sequence divergence.
R.N. Trigiano, M.H. Ament, M.T. Windham and J.K. Moulton
We thank Willard Witte for the gifts of the Cornus kousa cultivars used in this study and the financial support of the Tennessee Agricultural Experiment Station and the USDA-ARS through award 58-6404-2-00057.
Xinwang Wang, Robert N. Trigiano, Mark T. Windham, Renae DeVries, Timothy A. Rinehart, James M. Spiers and Brain Scheffler
The genus Cornus consists of many species, of which C. florida, C. kousa, C. mas, and C. stolonifera are four main ornamental species in North America, Asia, and Europe. For example, over 200 cultivars of C. florida alone have been developed for the nursery industry. Microsatellite loci, or SSR, are useful markers for studying genetic diversity and for creating linkage maps of the various species. The objective of this study was to investigate the genetic diversity between these four Cornus species and eight hybrids. Evaulation of the diversity will be useful in assessing the selection pressure of breeders and/or genetic drift of these dogwood cultivars/lines. Fifteen SSR primer pairs were selected to examine 56 Cornus cultivars and/or lines of the four species and hybrids. The study included 28 C. florida cultivars and lines, 15 C. kousa cultivars and lines, four C. stolonifera cultivars, one cultivar of C. mass and eight hybrids between various Cornus species. An exceptionally high level of diversity was detected among the 56 entries in both the number and size range of SSR alleles. A total of 95 alleles with an average of 7.8 alleles per loci were detected among these 56 genotypes. These selected Cornus cultivars and/or lines could be clustered into four to six subgroups. Some Cornus species were integrated into other species groups, suggesting gene flow between species via the breeding or evolution. SSR markers can contribute to the exploitation of genetic diversity for existing Cornus germplasm. For further study, examination of more SSR loci could explain more completely the diversity among these Cornus cultivars and lines.
Thomas J. Molnar, Megan Muehlbauer, Phillip A. Wadl and John M. Capik
kousa dogwood released from the program. While available cultivars of C. florida , our native flowering dogwood, express a range of bract colors from white to dark red, bract colors of kousa dogwood ( C. kousa ) are much more limited ( Cappiello and
Phillip A. Wadl, Mark T. Windham, Richard Evans and Robert N. Trigiano
The genus Cornus contains 58 species of trees, shrubs, and herbs that are mostly distributed throughout the northern hemisphere ( Xiang et al., 2006 ). Flowering dogwood ( C. florida ), kousa dogwood ( C. kousa ), and their interspecific hybrids
Hailin Liu, Cunmeng Qian, Jian Zhou, Xiaoyan Zhang, Qiuyue Ma and Shuxian Li
C. kousa var. Chinensis , Fu et al. (2013) indicated that the dormancy of chinese dogwood could be classified as physiological dormancy due to the existence of inhibitory substances in the endosperm. However, the causes of C. florida seed