Shoots were regenerated from cotyledons of mature stored seed of three peach rootstock cultivars (`Flordaguard', `Nemared', and `Medaguard'). Shoot regeneration rates were highest when cotyledons were cultured for 3 weeks in darkness on Murashige and Skoog (MS) medium with 2.5% sucrose and a combination of IBA (1.25 or 2.5 μm) and TDZ (6.25 or 12.5 μm). Regeneration rates for `Flordaguard', `Nemared', and `Nemaguard' were as high as 60%, 33%, and 6%, respectively. Length of seed storage (1 to 3 years) did not affect regeneration rates. Seventy percent of regenerated shoots produced rooted plants. This regeneration method is rapid and simple, and stored seed can be used year-round. It may be a useful regeneration system for gene transfer in seed-propagated peach rootstocks. Chemical names used: 5 indole-3-butyric acid (IBA); thidiazuron (TDZ).
M.R. Pooler and R. Scorza
Pollen from the doubled haploid peach [Prunus persica (L.) Batsch] `Hall-D' was irradiated with 0, 290, 530, 820, 1000, 5000, or 9000 Gray (Gy) of gamma radiation, 113 μW·cm-2 of ultraviolet (UV) radiation, or exposed to 100 °C for 2 h. In vitro pollen germination percentages were recorded and pollen was used to pollinate more than 10,000 emasculated or male-sterile peach flowers. Although pollen germination in vitro was stimulated by <1000 Gy of gamma irradiation, seed set following pollination was greatly reduced in all treatments. These results suggest that low levels of irradiation are sufficient to render pollen infertile while still maintaining germination capacity. Such results may be useful for pollination-induced parthenogenetic egg division for the production of maternally derived haploids and for the production of interspecific hybrids.
M.R. Pooler and P.W. Simon
The effects of cold storage, photoperiod, and growth temperature on flowering incidence in four clones of garlic (Allium sativum L.) were studied. While flowering percentage was influenced most by clone, interactions with photoperiod, growth temperature, and storage occurred. Clone R81 flowered equally well in all conditions, whereas flowering percentage of clones D129, D130, and PI485592 was reduced by cold (4C) storage of either bulbs or plants, long (16-h) photoperiod, and at 18C relative to 10C. The highest flowering percentage in all garlic clones was achieved by growing plants at 10C under short (9- to 10-h) photoperiod with no cold storage of bulbs before planting.
Sandra M. Reed and Margaret R. Pooler
R.M. Pool, R.M. Dunst, and A.N. Lakso
In two 4-year studies, `Concord' (Vitis labruscana, Bailey) cane pruning weight, yield, and soluble solids content were similar for vines growing under herbicide and cultivation treatments. In a vineyard with shallow soil, vines grown under mulch had a significantly greater increase in cane pruning weight than did vines grown with sod middles. Growth suppression of sod-managed vines occurred only in relatively dry years. While there was annual variation in vine response to herbicide and cultivation treatments, the cumulative responses over the 4-year study were similar for these treatments. A second vineyard where soil was less restrictive for root growth did not respond to the replacement of clean cultivation with herbicide treatments. In both experiments, there was no apparent advantage of two instead of a single herbicide application, and there was no difference between the budbreak, as opposed to bloom timing, of herbicide application.
B.I. Reisch, R.M. Pool, M.H. Martens, R.S. Luce, G. Remaily, and T.J. Zabadal
Margaret R. Pooler, Louise G.H. Riedel, S.E. Bentz, and A.M. Townsend
Controlled pollinations were made between five hemlock (Tsuga) species from eastern North America and Asia, resulting in over 5700 germinating seedlings. A subset of putative hybrid seedlings from each cross was tested for authenticity by various DNA marker systems. The most reliable and useful system for verifying hybrids was amplified fragment-length polymorphism (AFLP) markers. Hybridizations between the eastern North American species, T. canadensis [L.] Carriere and T. caroliniana Engelm., and the Asian species, T. chinensis (Franch.) E. Pritz., were used as a model to test the inheritance, reliability, and ease of use of these markers. Using AFLP markers, we were able to verify 58 hybrids between T. caroliniana and T. chinensis, one hybrid between T. caroliniana and T. canadensis, but could find no definitive hybrids between T. canadensis and T. chinensis. Results using other marker systems, including RAPD, SCAR, ITS, and SSR, are also presented.
B.I. Reisch, R.M. Pool, W.B. Robinson, T. Henick-Kling, B.K. Gavitt, J.P. Watson, M.H. Martens, R.S. Luce, and H.C. Barrett
Lucy K. Bradley, Ellen M. Bauske, Thomas A. Bewick, John R. Clark, Richard. E. Durham, Gail Langellotto, Mary H. Meyer, Margaret Pooler, and Sheri Dorn
Consumer horticulture encompasses a wide array of activities that are practiced by and of interest to the gardening public, garden-focused nongovernmental organizations, and gardening-related industries. In a previous publication, we described the current lack of funding for research, extension, and education in consumer horticulture and outlined the need for a strategic plan. Here, we describe our process and progress in crafting a plan to guide university efforts in consumer horticulture, and to unite these efforts with stakeholders’ goals. In 2015, a steering committee developed a first draft of a plan, including a mission statement, aspirational vision, core values, goals, and objectives. This draft was subsequently presented to and vetted by stakeholders at the 2015 American Society for Horticultural Science Consumer Horticulture and Master Gardeners (CHMG) working group workshop, a 2015 Extension Master Gardener Coordinators’ webinar, and a 2015 meeting in Washington, DC. Feedback received from these events is being used to refine and focus plan goals and objectives. The most recent working draft of the plan can be found on the website, where stakeholders and other interested parties can register to receive updates and to provide input into the process.