@article{phillips_ranney_touchell_eaker_2016, title={Fertility and reproductive pathways of triploid flowering pears (Pyrus sp.)}, volume={51}, number={8}, journal={HortScience}, author={Phillips, W. D. and Ranney, T. G. and Touchell, D. H. and Eaker, T. A.}, year={2016}, pages={968–971} }
 @article{touchell_ranney_panthee_gehl_krings_2016, title={Genetic diversity, cytogenetics, and biomass yields among taxa of giant reeds (Arundo species)}, volume={141}, number={3}, journal={Journal of the American Society for Horticultural Science}, author={Touchell, D. H. and Ranney, T. G. and Panthee, D. R. and Gehl, R. J. and Krings, A.}, year={2016}, pages={256–263} }
 @article{palmer_gehl_ranney_touchell_george_2014, title={Biomass yield, nitrogen response, and nutrient uptake of perennial bioenergy grasses in North Carolina}, volume={63}, ISSN={["1873-2909"]}, DOI={10.1016/j.biombioe.2014.02.016}, abstractNote={Although perennial grasses show considerable potential as candidates for lignocellulosic bioenergy production, these crops exhibit considerable variation in regional adaptability and yield. Giant miscanthus (Miscanthus × giganteus Greef & Deuter), Miscanthus sinensis Anderss. 'Gracillimus' and MH2006, plume grass (Saccharum arundinaceum Retz.), ravenna grass (Saccharum ravennae (L.) L.), switchgrass (Panicum virgatum L. 'Alamo'), and giant reed (Arundo donax L.) field plots were established in 2008, treated with four nitrogen (N) fertilizer rates (0, 34, 67, 134 kg ha−1 y−1), and harvested annually in winter from 2008 to 2011. Giant reed, 'Gracillimus', switchgrass, MH2006, giant miscanthus and ravenna grass at the Mountain site produced mean dry matter yields of 22.8, 21.3, 20.9, 19.3, 18.4, and 10.0 Mg ha−1 y−1, respectively (averaged over the last two years). Dry matter yields at the Coastal site for giant reed, giant miscanthus, switchgrass, ravenna grass, and 'Gracillimus' were 27.4, 20.8, 20.1, 14.3, and 9.4 Mg ha−1 y−1, respectively (averaged over the last two years). Increasing N rates up to 134 kg N ha−1 did not have a consistent significant effect on biomass production. High yields coupled with high mortality for plume grass at both sites indicates its potential as a bioenergy crop and need for continued improvement. Overall, the perennial grasses in this study had low nutrient removal, although giant reed and plume grass often removed significantly more N, P, K and S compared with Miscanthus spp. and switchgrass. Our results indicate that giant reed, giant miscanthus, and switchgrass are productive bioenergy crops across geographic regions of North Carolina.}, journal={BIOMASS & BIOENERGY}, author={Palmer, Irene E. and Gehl, Ronald J. and Ranney, Thomas G. and Touchell, Darren and George, Nic}, year={2014}, month={Apr}, pages={218–228} }
 @article{oates_ranney_touchell_viloria_2014, title={Campsis xtagliabuana 'Chastity': A Highly Infertile Triploid Trumpet Vine}, volume={49}, ISSN={["2327-9834"]}, DOI={10.21273/hortsci.49.3.343}, abstractNote={Campsis spp. Lour. (Bignoniaceae) are commonly known as trumpet vines or trumpetcreepers. The genus contains only two species, C. radicans (L.) Seem. and C. grandiflora K. Schum., and their interspecific hybrid, C. ·tagliabuana (Vis.) Rehder (Huxley et al., 1992). Campsis radicans is native throughout eastern North America and is often seen growing along fencerows, utility lines, and embankments. It is an aggressive woody vine (reaching up to 12 m) that frequently sprouts from the base (Anderson, 1933; Uva et al., 1997). The showy trumpetshaped flowers form on current year’s growth from mid-June through October. Flower colors of different cultivars include yellow, orange, and red. Campsis grandiflora is also a rapid grower with larger and more open funnel-shaped flowers than C. radicans, which typically has apricot/orange flowers. Campsis ·tagliabuana has intermediate characteristics between the two parental species. Although C. radicans is widely adaptable with a long bloom period and showy display of flowers, it can seed prolifically, grows quickly, and is considered weedy in many areas. The highly infertile, C. ·tagliabuana ‘Chastity’ was developed to minimize the reseeding potential of Campsis while maintaining the desirable landscape characteristics. The average number of seedlings per pollinated flower, an overall measure of female fecundity, was reduced from 119.3 for C. radicans to only 0.008 for ‘Chastity’, a reduction in fertility of 99.993%.}, number={3}, journal={HORTSCIENCE}, author={Oates, Kelly M. and Ranney, Thomas G. and Touchell, Darren H. and Viloria, Zenaida}, year={2014}, month={Mar}, pages={343–345} }
 @article{lattier_touchell_ranney_2014, title={Micropropagation of an interspecific hybrid dogwood (Cornus 'NCCH1')}, volume={14}, number={4}, journal={Propagation of Ornamental Plants}, author={Lattier, J. D. and Touchell, D. H. and Ranney, T. G.}, year={2014}, pages={184–190} }
 @article{oates_touchell_ranney_2013, title={Induced Variation in Tetraploid Rudbeckia subtomentosa 'Henry Eilers' Regenerated from Gamma-irradiated Callus}, volume={48}, ISSN={["2327-9834"]}, DOI={10.21273/hortsci.48.7.831}, abstractNote={Rudbeckia subtomentosa ‘Henry Eilers’ is an adaptable and popular garden plant; however, reduction in height and increased novelty in flower color would be desirable. The effect of gamma radiation dose on in vitro survival and development, and ex vitro fertility, phenology, and morphology of tetraploid Rudbeckia subtomentosa ‘Henry Eilers’ was investigated. In vitro embryogenic callus was treated with gamma radiation (0, 5, 10, 20, or 40 Gy). Rooted microshoots were established ex vitro and evaluated for morphology (plant height, number of flowers, diameter of the terminal flowers, diameter of the secondary flowers, number of stems, number of nodes, and internode length), date of first anthesis, winter survival, and pollen fertility on mature, second-year plants. Callus survival had no response to dose 2 months after treatment; however, microshoot number was significantly reduced with increasing dose. In vitro microshoot survival continued to decline at higher doses up to 4 months after treatment. Plant height, average stem height, number of flowers, flower diameter, percent winter survival, and pollen viability were all reduced with increasing radiation dose. Date of first anthesis was also delayed with increased radiation dose. Several off phenotypes were recorded including increased apical splitting of the ray florets in several plants. Gamma radiation was somewhat effective for reducing the height of R. subtomentosa ‘Henry Eilers,’ but flower morphology, flower number, and plant overwintering survival were often negatively affected with increasing radiation dose. Treating callus with low levels of gamma radiation (5–10 Gy) resulted in relatively high in vitro and field survival while inducing a range of other mutations that could be selected.}, number={7}, journal={HORTSCIENCE}, author={Oates, Kelly M. and Touchell, Darren H. and Ranney, Thomas G.}, year={2013}, month={Jul}, pages={831–834} }
 @article{oates_ranney_touchell_2012, title={Influence of Induced Polyploidy on Fertility and Morphology of Rudbeckia Species and Hybrids}, volume={47}, ISSN={["2327-9834"]}, DOI={10.21273/hortsci.47.9.1217}, abstractNote={Rudbeckia spp. are adaptable and valuable ornamental wildflowers. Development of new varieties of Rudbeckia spp., with improved commercial characteristics, would be highly desirable. Interspecific hybridization and induced polyploidy may be avenues for improvement within the genus. The objective of this study was to evaluate fertility, morphology, phenology of flowering, and perennialness (overwintering survival) for lines of diploid and induced allotetraploids of R. subtomentosa × hirta and diploid and autotetraploids of R. subtomentosa ‘Henry Eilers’. Polyploid lines were developed and propagated in vitro and then grown ex vitro in a randomized complete block design with 12 replications. Compared with their diploid counterparts, autotetraploid lines of R. subtomentosa ‘Henry Eilers’ had similar internode lengths, plant heights, number of stems, flowering times (date at first anthesis), and fall and spring survival (100%); reduced number of inflorescences and male and female fertility; and increased inflorescence diameters. Compared with their diploid counterparts, allotetraploids of R. subtomentosa × hirta had similar internode lengths, reduced number of inflorescences, delayed flowering times, and increased pollen staining. Allotetraploids had limited male and female fertility compared with no detectable fertility in their diploid counterparts. Plant height and number of stems either decreased or showed no change with induced allotetraploidy. Spring survival of diploid hybrid genotypes ranged from 0% to 82% and was not improved in the allotetraploid hybrids. For a given genotype, some polyploidy lines varied significantly in certain morphological traits (e.g., plant height) indicating somaclonal variation may have developed in vitro or there were variable genomic or epigenetic changes associated with induced polyploidy.}, number={9}, journal={HORTSCIENCE}, author={Oates, Kelly M. and Ranney, Thomas G. and Touchell, Darren H.}, year={2012}, month={Sep}, pages={1217–1221} }
 @article{rounsaville_touchell_ranney_2011, title={Fertility and Reproductive Pathways in Diploid and Triploid Miscanthus sinensis}, volume={46}, ISSN={["2327-9834"]}, DOI={10.21273/hortsci.46.10.1353}, abstractNote={Miscanthus sinensis Andersson is a popular ornamental grass and has additional potential as a bioenergy crop. In some regards, the ability of M. sinensis to withstand a broad range of climatic and cultural conditions is desirable, but its propensity to rapidly colonize open and disturbed environments has allowed it to naturalize and become weedy in some regions in the United States. Considering the value of this crop, the development and documentation of infertile clones would be desirable. Triploid plants were evaluated for male and female fertility using pollen viability staining and seed set and germination, respectively. Pollen viability staining, seed set, and seed germination from triploid plants were reduced compared with diploids but varied considerably within each cytotype. Overall, relative female fertility of individual triploids clones [(% seed set × % germination for triploid)/(% seed set × % germination for diploid control)] was reduced substantially and ranged from 49% to 0.7%. Additionally, the reproductive pathways of triploid plants were examined by evaluating the 2C genome sizes of progeny derived from open pollination. The limited progeny arising from open-pollinated triploids were predominantly aneuploids with 2C genome sizes intermediate between diploids and triploids. There was no clear evidence of apomixis, selfing, or triploid × triploid fertilization events observed among triploid parents. Formation of unreduced gametes was rare for both ploidy levels (≈1%). The considerable reduction in female fertility in some triploid clones combined with the limited production of primarily aneuploid progeny provides highly infertile alternatives to existing diploid cultivars.}, number={10}, journal={HORTSCIENCE}, author={Rounsaville, Todd J. and Touchell, Darren H. and Ranney, Thomas C.}, year={2011}, month={Oct}, pages={1353–1357} }
 @article{rounsaville_touchell_ranney_blazich_2011, title={Micropropagation of Mahonia ‘Soft Caress’}, volume={46}, DOI={10.21273/hortsci.46.7.1010}, abstractNote={Mahonia ‘Soft Caress’ is a unique new cultivar exhibiting a compact form and delicate evergreen leaves. Protocols for micropropagation of M. ‘Soft Caress’ were developed to expedite multiplication and serve as a foundation for future work with other taxa of Mahonia Nutt. Combinations of sucrose at 30 or 45 g·L−1 in conjunction with Gamborg B5 (B5), Quoirin and Lepoivre (QL), and Murashige and Skoog (MS) basal media as well as other selected growth regulator treatments were evaluated as multiplication media. Rooting of microcuttings was conducted in vitro using combinations of indole-3-butyric acid (IBA) at 0, 2, 4, 8, or 16 μM under either light or dark. Quick dip treatments with aqueous solutions of the potassium (K) salt (K-salt) of IBA at 0, 5.2, 10.4, 20.7, or 41.4 μM were tested in a second experiment for ex vitro rooting. Media containing B5 basal salts and vitamins supplemented with sucrose at 30 g·L−1, 5 μM 6-benzylaminopurine, 5 μM kinetin, 0.5 μM indole-3-acetic acid, and 2.5 μM gibberellic acid yielded 2.80 ± 0.14 microshoots with a mean length of 14.76 ± 0.63 mm over a 6-week culture period and was an optimal multiplication media. Light treatment and IBA concentration had a significant effect on rooting percentages. Microcuttings treated with 8 μM IBA and maintained in the dark resulted in the best rooting (70%) and ex vitro establishment.}, number={7}, journal={Hortscience}, author={Rounsaville, T.J. and Touchell, D.H. and Ranney, T.G. and Blazich, F.A.}, year={2011}, pages={1010–1014} }
 @article{hebert_touchell_ranney_lebude_2010, title={In vitro shoot regeneration and polyploid induction of rhododendron 'Fragrantissimum Improved'}, volume={45}, number={5}, journal={HortScience}, author={Hebert, C. J. and Touchell, D. H. and Ranney, T. G. and LeBude, A. V.}, year={2010}, pages={801–804} }
 @article{meyer_touchell_ranney_2009, title={In Vitro Shoot Regeneration and Polyploid Induction from Leaves of Hypericum Species}, volume={44}, ISSN={["2327-9834"]}, DOI={10.21273/hortsci.44.7.1957}, abstractNote={Hypericum L. H2003-004-016 is a complex hybrid among Hypericum frondosum Michx., Hypericum galioides Lam., and Hypericum kalmianum L. and exhibits valuable ornamental characteristics, including compact habit, bluish green foliage, and showy flowers. Inducing polyploidy may further enhance the ornamental traits of this hybrid and provide new opportunities for hybridizing with other naturally occurring polyploid Hypericum sp. In this study, in vitro shoot regeneration and treatment of regenerative callus with the dinitroaniline herbicide oryzalin (3,5-dinitro-N4,N4-dipropylsufanilamide) were investigated as a means of inducing allopolyploidy. First, in vitro regeneration was optimized for callus and shoot induction by culture of leaf explants on medium supplemented with benzylamino purine (BA) or meta-topolin (mT) at 5, 10, or 15 μM in combination with indoleacetic acid (IAA) at 0, 1.25, 2.5, or 5 μM. Both BA and mT treatments successfully induced regenerative callus and shoots. Multiple regression analysis estimated maximum regenerative callus (94%) and shoot induction (18 shoots per explant) in medium supplemented with 5 μM BA and 3.75 μM IAA. In the second part of the study, exposure of regenerative callus to oryzalin at 0, 7.5, 15, 30, 60, or 90 μM for durations of 3, 6, or 9 d was investigated for polyploid induction. There was no survival for any of the calli in the 60- or 90-μM oryzalin treatments, but calli subjected to the other treatments exhibited some survival and polyploid induction. Duration had no effect on callus survival or ploidy level, but oryzalin concentration was a significant factor in both. The greatest percentage (44%) of polyploids was induced with 30 μM oryzalin. Spontaneous chromosome doubling was observed in 8% of control explants receiving no oryzalin treatment.}, number={7}, journal={HORTSCIENCE}, author={Meyer, Elisabeth M. and Touchell, Darren H. and Ranney, Thomas G.}, year={2009}, month={Dec}, pages={1957–1961} }