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Lisa L. Baxter and Brian M. Schwartz

Bermudagrass (Cynodon spp.) is the foundation of the turfgrass industry in most tropical and warm-temperate regions. Development of bermudagrass as a turfgrass began in the early 1900s. Many of the cultivars commercially available today have been cooperatively released by the U.S. Department of Agriculture Agricultural Research Service (USDA-ARS) and the University of Georgia at the Coastal Plain Experiment Station in Tifton, GA.

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Wayne W. Hanna and Brian M. Schwartz

Open access

Wayne W. Hanna and Brian M. Schwartz

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Ryan N. Contreras, John M. Ruter, and Brian M. Schwartz

Japanese-cedar [Cryptomeria japonica (L.f.) D. Don] represents an alternative to leyland cypress [×Cuprocyparis leylandii (A.B. Jacks. & Dallim.) Farjon] as an evergreen screen or specimen plant for landscapes. It performs well under a range of soil and environmental conditions but has been underused attributable, in part, to unsightly winter browning caused by photoinhibition. In previous studies, chance seedlings that did not exhibit winter browning were identified as tetraploids. The current study was conducted to induce polyploidy in japanese-cedar. Approximately 600 seedlings were sprayed with 150 μM oryzalin + 0.1% SilEnergy™ for 30 consecutive days under laboratory conditions. Two hundred thirty-seven seedlings with thickened and twisted leaves were selected, transplanted, and grown in a glasshouse for 120 days. Seedling ploidy levels were analyzed using flow cytometry 180 days after treatment (DAT), identifying 197 (83.1%) tetraploids, 22 (9.3%) cytochimeras, and 18 (7.6%) diploids. Morphology of induced tetraploids was similar to that previously described and provided a phenotypic marker during selection that was over 92% accurate. A random subset of 20 tetraploid individuals was analyzed 270 DAT and were found to contain only tetraploid cells in the leaves analyzed, confirming stability over this period. This study demonstrated the use of oryzalin for inducing tetraploids in japanese-cedar, which we predict will be effective in other gymnosperms.

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Wayne W. Hanna, S. Kristine Braman, and Brian M. Schwartz

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Wayne W. Hanna, S. Kristine Braman, and Brian M. Schwartz

Free access

Wayne W. Hanna, S. Kristine Braman, and Brian M. Schwartz

Free access

Karen R. Harris-Shultz, Brian M. Schwartz, and Jeff A. Brady

The release of the bermudagrass (Cynodon spp.) triploid hybrid ‘Tifgreen’ revolutionized southeastern U.S. golf course greens. Off-types within this cultivar began to be identified soon after the initial plantings, and through the last 50 years, many of the best performing off-types have been released as new cultivars. Examination of some of the most popular somatic mutants with a new set of 47 simple sequence repeat (SSR) markers and 23 previously discovered genomic SSR markers identified five polymorphic fragments (as compared with ‘Tifgreen’) among three cultivars, TifEagle, MiniVerde, and Tifdwarf. Each polymorphism appears to be a slight increase/decrease in microsatellite repeat number and the polymorphic fragments are unique for each cultivar. Two polymorphic fragments were identified that were unique to ‘Tifdwarf’, one polymorphic fragment was unique to ‘TifEagle’, and two polymorphic fragments were unique to ‘MiniVerde’. Furthermore, three of the five polymorphic markers display an additional allele only in the shoot tissue but not in the root tissue of ‘TifEagle’ and ‘Tifdwarf’. This finding suggests that ‘TifEagle’ and ‘Tifdwarf’ are somatic chimeras. This set of SSR markers identifies repeatable polymorphic fragments among multiple ‘Tifgreen’-derived cultivars and gives insight into the nature of the mutations that exist within ‘Tifgreen’.

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Wayne W. Hanna, Brian M. Schwartz, Ann R. Blount, Gary Knox, and Cheryl Mackowiak