@article{deans_palmer_touchell_ranney_2021, title={In Vitro Induction and Characterization of Polyploid Hydrangea macrophylla and H. serrata}, volume={56}, ISSN={["2327-9834"]}, DOI={10.21273/HORTSCI15783-21}, abstractNote={Hydrangea macrophylla (Thunb.) Ser. and H. serrata (Thunb.) Ser. are popular and commercially important landscape and floriculture crops. Although both species are typically diploid, induced polyploids often exhibit horticulturally valuable traits. Procedures for inducing polyploidy vary by species and often have low or inconsistent efficacy. In this study, oryzalin and nitrotyrosine were investigated as in vitro mitotic inhibitors for inducing polyploidy in H. macrophylla ‘Robert’ and H. serrata ‘MAK20’. First, shoot apices of ‘MAK20’ were treated with 15 μm oryzalin for 0, 2, 4, 6, or 8 days, and the ploidy of shoots was determined after 8 weeks. A regression analysis showed that the proportion of polyploids (tetraploid plus mixoploid shoots) increased with the exposure duration. During a follow-up experiment, ‘MAK20’ and ‘Robert’ were treated with oryzalin (0 or 15 μm) and nitrotyrosine (0, 25, 50, and 100 µm for ‘MAK20’ and 0, 12.5, 25, 50, and 100 µm for ‘Robert’) in a factorial treatment arrangement. Oryzalin, nitrotyrosine, and their interaction influenced polyploid frequency for ‘Robert’, whereby the combination of oryzalin (15 μm) and nitrotyrosine (50 μm) resulted in the highest polyploid induction of 50%. Oryzalin influenced polyploid frequency for ‘MAK20’ ( = 30.4%), but not nitrotyrosine or the interaction between nitrotyrosine and oryzalin. Morphology and pollen germination of these autotetraploid ‘Robert’, ‘MAK20’, and previously developed autotetraploid H. macrophylla ‘David Ramsey’ plants were compared with their diploid counterparts 1 year after plants were moved ex vitro. Compared with diploids, tetraploid hydrangeas had larger leaves, thicker stems, lower leaf area/fresh weight ratios, and longer internodes. Although all tetraploids exhibited fewer inflorescences per plant, both H. macrophylla cultivars had larger inflorescence diameters and ‘David Ramsey’ had a greater number of showy florets (sterile florets with enlarged, decorative sepals) per inflorescence. Sepal colors were compared using International Commission on Illumination L*a*b* color space. Tetraploid ‘MAK20’ had lower L* values (darker sepals), and tetraploid ‘Robert’ and ‘MAK20’ both had higher a* values (redder sepals). Pollen germination rates were greatly reduced in all tetraploid lines, but they retained some viability. These results provide an effective protocol for in vitro polyploid induction of Hydrangea sp. and documented certain desirable traits associated with tetraploid phenotypes.}, number={6}, journal={HORTSCIENCE}, author={Deans, Lauren E. and Palmer, Irene E. and Touchell, Darren H. and Ranney, Thomas G.}, year={2021}, month={Jun}, pages={709–715} }
 @article{ranney_ryan_deans_lynch_2018, title={Cytogenetics and Genome Size Evolution in Illicium L.}, volume={53}, ISSN={["2327-9834"]}, DOI={10.21273/hortsci12922-18}, abstractNote={Illicium is an ancient genus and member of the earliest diverging angiosperms known as the Amborellales, Nymphaeales, and Austrobaileyales (ANA) grade. These adaptable, broadleaf evergreen shrubs, including ≈40 species distributed throughout Asia and North America, are valued for diverse culinary, medicinal, and ornamental applications. The study of cytogenetics of Illicium can clarify various discrepancies and further elucidate chromosome numbers, ploidy, and chromosome and genome size evolution in this basal angiosperm lineage and provide basic information to guide plant breeding and improvement programs. The objectives of this study were to use flow cytometry and traditional cytology to determine chromosome numbers, ploidy levels, and relative genome sizes of cultivated Illicium. Of the 29 taxa sampled, including ≈11 species and one hybrid, 2C DNA contents ranged from 24.5 pg for Illicium lanceolatum to 27.9 pg for Illicium aff. majus. The genome sizes of Illicium species are considerably higher than other ANA grade lineages indicating that Illicium went through considerable genome expansion compared with sister lineages. The New World sect. Cymbostemon had a slightly lower mean 2C genome size of 25.1 pg compared with the Old World sect. Illicium at 25.9 pg, providing further support for recognizing these taxonomic sections. All taxa appeared to be diploid and 2n = 2x = 28, except for Illicium floridanum and Illicium mexicanum which were found to be 2n = 2x = 26, most likely resulting from dysploid reduction after divergence into North America. The base chromosome number of x = 14 for most Illicium species suggests that Illicium are ancient paleotetraploids that underwent a whole genome duplication derived from an ancestral base of x = 7. Information on cytogenetics, coupled with phylogenetic analyses, identifies some limitations, but also considerable potential for the development of plant breeding and improvement programs with this genus.}, number={5}, journal={HORTSCIENCE}, author={Ranney, Thomas G. and Ryan, Connor F. and Deans, Lauren E. and Lynch, Nathan P.}, year={2018}, month={May}, pages={620–623} }