zones that nearly span the latitudinal range of the United States. Thus, if systematically exploited for breeding interspecific hybrids, C. americana may enable the expansion of commercial hybrid hazelnut production to a wide portion of the eastern and
Ronald S. Revord, Sarah T. Lovell, John M. Capik, Shawn A. Mehlenbacher, and Thomas J. Molnar
Desire Djidonou, Amarat H. Simonne, Karen E. Koch, Jeffrey K. Brecht, and Xin Zhao
currently available, interspecific, hybrid rootstocks were developed directly from wild species. These rootstocks tend to increase plant vegetative growth and fruit yields ( Di Gioia et al., 2010 ; Leonardi and Giuffrida, 2006 ) to such an extent that
Michael Kantar, Kevin Betts, Brent S. Hulke, Robert M. Stupar, and Donald Wyse
; Sacks et al., 2003 ; Wang et al., 2009 ). One of the promising wild species being investigated for creating a perennial sunflower crop is H. tuberosus . Interspecific hybrids between H. annuus and H. tuberosus also show promise as breeding material
Madeline Wimmer, Beth Ann Workmaster, and Amaya Atucha
2016 harvests for ‘Brianna’, ‘Frontenac’, ‘La Crescent’, and ‘Marquette’ cold climate, interspecific hybrid grape cultivars trained in high cordon (HC), Scott Henry (SH), and vertical shoot positioning (VSP) systems. z Fruit chemistry. There were very
Yan Ma, David H. Byrne, and Jing Chen
An objective of our rose breeding research is to transfer resistance to blackspot and other diseases from wild diploid species to modern rose cultivars. Interspecific hybrids among blackspot-resistant diploid species were chosen for chromosome doubling to produce fertile amphidiploids that could be hybridized to the tetraploid commercial germplasm. Five such F1 interspecific hybrids were treated with colchicine. The study included two different application procedures (shake in colchicine solution or colchicine in media), four colchicine concentrations (0.05%, 0.1%, 0.15%, and 0.20%), and five treatment periods (1, 3, 5, 8, and 10 days). After colchicine treatment, all the materials were cultured in vitro. One thousand-thirty-seven surviving explants were selected for typical “gigas” characteristics of doubled diploids. Chromosome counts on shoot tips of these selected genotypes confirmed 15 amphidiploids. The best colchicine treatment varied among the interspecific hybrids. Higher colchicine concentrations or duration reduced growth rating, rooting, and percent survival. The recognition of amphiploids and ploidy chimeras from young seedlings will also be discussed.
Young-ju Kim and David H. Byrne
The hybrid origin of 23 rose (Rosa spp.) accessions was examined with three isozymes: acid phosphatase (E.C.126.96.36.199), malate dehydrogenase (E.C.188.8.131.52), and phosphoglucose isomerase (E.C.184.108.40.206). All three isozymes were useful for interspecific hybrid verification. This procedure was effective if the putative parents were known and differed in isozyme phenotype. To verify the origin of hybrid species or cultivars with hybrid origins, isozymes were useful but limited by the number of generations since the original hybridization and the number of accessions of the putative parental species assayed.
Yan Ma, David H. Byrne, and Jing Chen
A high priority in rose (Rosa spp.) breeding research is the transfer of disease resistance, especially to black spot (Diplocarpon rosae Lib.), from wild diploid Rosa species to modern rose cultivars. To this end, amphidiploids (2n = 4x = 28) were induced with colchicine from five interspecific diploid (2n = 2x = 14) hybrids involving the black spot resistant diploid species R. wichuraiana Crép, R. roxburghii Thratt., R. banksiae Ait., R. rugosa rubra Hort., and R. setigera Michaux. Two application procedures (agitation of excised nodes in colchicine solution or tissue culture of shoots on medium with colchicine), five colchicine concentrations (0.0, 1.25, 2.50, 3.76, and 5.01 mmol), and five durations (2, 3, 5, 8, and 10 d) were used. After colchicine treatment, the materials were cultured in vitro and the surviving explants were examined for the “gigas” characteristics typical of doubled diploids. Chromosome counts of morphologically suspect genotypes confirmed 15 amphidiploids among 1109 plants that survived colchicine treatment. Although the effect of colchicine treatment varied some among interspecific hybrids, 2.50 mmol for 48 h of node agitation or 1.25 mmol for at least 5 d of shoot culture were optimal.
Chalita Sriladda, Heidi A. Kratsch, Steven R. Larson, Thomas A. Monaco, FenAnn Shen, and Roger K. Kjelgren
: aesthetic and extreme drought tolerance qualities of S. rotundifolia but greater tolerance of wet, disturbed soils and faster growth of S. argentea . This study describes an interspecific hybrid between the two species in terms of genetics and leaf
Wenjing Guan, Xin Zhao, and Donald J. Huber
of particular importance in elucidating rootstock–scion–environment interactions. Interspecific hybrid squash rootstocks ( C. maxima × C . moschata ), with characteristic vigorous root systems, tolerance to cold and saline conditions, and
Mohammad Akbari, Hossein Hokmabadi, Mohsen Heydari, and Ali Ghorbani
scions. Arota is a new Iranian interspecific hybrid ( Pistacia integerrima ♂ × Pistacia atlantica ♀ ) pistachio rootstock selected from the progeny of 222 controlled crosses made in 2013 and 2014. Of these crosses, the most vigorous seedlings were