Physostegia purpurea Blake is a native, herbaceous perennial that has potential as a field-grown cut flower. Physostegia stems were harvested with one third of the florets open and were recut underwater in the laboratory. Fresh cut flowers treated with silver thiosulfate (STS) and held in a 2% preservative solution lasted 14 days, while control stems in deionized water (DI) lasted 6 days. Cut stems placed in darkness at 0C for 1 week had 8 days of vase life after removal from storage and treatment with STS and preservative, while stems held in DI after storage lasted only 4 days. Stems held dry at 22.5C and 43% RH for 8 hours before being placed in preservative had similar vase life as flowers placed in preservative immediately after harvest.
John W. Kelly and Terri W. Starman
Shannon E. Beach* and Terri W. Starman
Diascia ×hybrida (diascia) is a cool season vegetative annual produced in 6 weeks in an 11.4-cm pot under greenhouse production. Early experiments noted that during simulated shipping in a growth chamber at 26.7 ± 0.3 °C, 0 μmol·m-2·s-1 PPF and 50% RH, diascia flowers abscised. To test the effect of 1-MCP on retention of flowers during shipping, three hundred diascia plants were grown under temperature set points of 24°/18 °C day/night in a glass greenhouse. Three harvests of 42 plants each were made as plants became marketable i.e., open flowers on six racemes. The treatments were factorial with three shipping durations (0, 1, or 2 days) and two 1-MCP (1-Methylcyclopropene, Ethylboc, Floralife, Waterboro, S.C.) treatments (0 mg·L-1 and the commercially recommended application rate) and seven plants per treatment. Plants were boxed and sealed under 4-mL clear plastic tarps with duct tape and then treated with 1-MCP gas or water for 4 hours before moving to the growth room (19 °C, 10 μmol·m-2·s-1 PPF) for 2 weeks. They remained in the boxes for the duration of simulated shipping treatments. Flower number, racemes with open flowers and a quality rating were given when removed from the shipping boxes. For plants in the first and second harvests, 1-MCP significantly reduced flower and raceme abscission 1 week after shipping regardless of shipping duration; this was not seen in the third harvest. Two weeks post shipment there was no difference in flower numbers between 1-MCP treated and untreated plants. With two exceptions, no differences among measured variables occurred due to shipping duration.
Shannon E. Beach* and Terri W. Starman
Vegetative annuals are increasing in popularity among greenhouse growers and consumers but little is known about their postharvest shelf life. Twenty-two cultivars from ten species of vegetative annuals were grown to marketability with optimum greenhouse culture. Plants were then subjected to one of three shipping durations (0, 1, or 2 days) in simulated shipping i.e., a growth chamber at 26.7 ± 0.3 °C, 0 μmol·m-2·s-1, and 50% relative humidity. The plants were then moved to simulated postharvest environment i.e., growth room at 21.1 ± 1.3 °C and 6 μmol·m-2·s-1 to evaluate shelf life. Flower number and plant quality rating were measured weekly in addition to observations of plant appearances. Some of the postharvest disorders noted on several species and cultivars were stem die back, leaf chlorosis, stem elongation, bud abortion, flower drop, and flower fading. The majority of the cultivars maintained their quality one-week postharvest although flower drop was common. After the first week of shelf life, decline in vegetative and reproductive tissues were noted in most plants. Cultivars from nine species: Argyranthemum frutescens (L.) Sch. Bip, Bracteantha bracteata (Vent.) Anderb. & Haegi, Calibrachoa hybrid Lave Lex, Diascia ×hybrida, Lantana camara L., Nemesia ×hybrida, Petunia ×hybrida, Sutera hybrida, and Sutera cordata showed decreased flower number and/or quality rating due to shipping duration, with increased shipping duration causing accelerated postharvest disorders. The only species unaffected by shipping duration was Angelonia angustifolia Benth.
Terri W. Starman and James E. Faust
Our objective was to determine the effect of planting date and pinching on flowering dates and plant size of field-grown garden mums. Experiments were conducted in the field during two consecutive growing seasons in 1997 and 1998. In one experiment, 15 to 20 cultivars were planted on five dates (14 May, 4 June, 25 June, 16 July, and 4 Aug.) and received no pinching, one manual pinch 2 weeks after potting, or two manual pinches 2 and 4 weeks after potting. In another experiment, four cultivars were planted at the five dates. Pinch treatments were control, one manual pinch, two manual pinches, one Florel spray at 500 mg·L–1, or two Florel sprays at the same time as the manual pinches but on separate plants. Data were collected for days to first color, first open flower, 10 open flowers, and full bloom. Height and width were measured at 10 open blooms. Although the 1998 season was warmer and caused heat delay, the flowering data followed the same trends as the 1997 experiments. Pinching delayed flowering for the early plant dates. Pinching did not affect plant height or plant width. Planting date affected days to 10 blooms for most early season varieties but not late-season varieties. Planting early produced larger plants and more uneven flowering and resulted in greater heat delay of heat-sensitive varieties. Florel delayed flowering and increased plant size. We concluded that pinching was not required to produce high-quality garden mums of many new cultivars.
Terri W. Starman and Millie S. Williams
The effects of concentration and method of application of uniconazole on growth and flowering of Scaevola aemula R. Br. `New Wonder', `Mini Pink Fan', `Purple Fan', and `Royal Fan', Scaevola albida (Sm.) Druce. `White Fan', and Scaevola striata `Colonial Fan' were studied, as was the efficacy of four other growth retardants on S. aemula `New Wonder'. Variables measured included plant width, flower stem number, flower stem length, flower number per stem, flower number per cm stem length, and days to flower. Uniconazole (1.0 mg·L–1) applied as a medium drench to S. aemula `New Wonder' reduced plant width and flower stem length without affecting flower stem number or time to flower. Flower number per stem and number of flowers per cm of stem length were increased, resulting in attractive, compact clusters of flowers. Paclobutrazol medium drench at 4.0 mg·L–1 gave similar results. Daminozide and ethephon sprays reduced plant width; however, flower number was reduced and ethephon delayed flowering. Ancymidol did not affect the parameters measured. When uniconazole drenches were applied to the other cultivars, plant width and flower stem length in all cultivars except `White Fan' decreased as rate increased. Spray applications reduced plant width of all cultivars except `Mini Pink Fan'. Flower stem length was not affected in any cultivar. Flowering habit was improved more in S. aemula `New Wonder', `Purple Fan', and `Royal Fan' than in the other cultivars. Chemical names used: α-cyclopropyl-α-(4-methoxyphenyl)-5-pyrimidinemethanol (ancymidol); butanedioic acid mono (2,2-dimethylhydrazide) (daminozide); (2-chloroethyl)phosphonic acid (ethephon); β-[(4-chlorophenyl)methyl]-α-(1,1-dimethylethyl)-1H-1,2,4-triazole-1-ethanol (paclobutrazol); (E)-(s)-1-(4-chlorophenyl)-4,4-dimethy-2-(1,2,4-triazol-1-yl)-pent-1-ene-3-ol (uniconazole).
Amy Lynn Bartel and Terri W. Starman
Angelonia angustifolia `Blue Pacific', Asteriscus maritimus `Compact Gold Coin', and Heliotropium aborescens `Fragrant Delight' are three vegetatively propagated species of annuals. The objective of this study was to find which plant growth regulator chemicals could be used to control height and produce compact, well-branched, flowering plants. The plants arrived as rooted plugs and were transplanted to 10-cm plastic containers. When the roots of the transplanted plugs reached the edge of their containers, 15 days after transplanting, the plant growth regulator chemicals were applied. Five different chemicals were used in spray applications at two rates measured in mg/L: ancymidol at 66 and 132; daminozide at 2500 and 5000; paclobutrazol at 20 and 40; ethephon at 500 and1000; and uniconazole at 10 and 20. One drench application of uniconazole at 1 and 2 mg/L and one control (water spray) were also used. Total plant height, plant width, flower number, node number, stem length, internode length, and numbers of days to visible bud were recorded. Ancymidol at both rates caused stunting and flower distortion in asteriscus; however, it was not effective on angelonia or heliotrope. Paclobutrazol and uniconazole sprays were ineffective in controlling height on all three species. Ethephon at both rates was effective in controlling height, and producing well-branched plants in all three species, yet it caused a delay in flowering. Uniconazole drench at both rates was also effective in controlling height but caused stunting. In general, daminozide at 5000 mg/L was most effective in controlling foliage height without a delay in flowering or decrease in flower size or number in all three species.
Hope K. Onken and Terri W. Starman
Argyranthemum frutescens `Sugar Baby', Calibrachoa hybrid `Million Bells Cherry Pink', and Orthosiphon stamineus `Lavender' are three vegetatively propagated specialty annuals that are recent introductions into the floriculture industry. It is important to understand how the growth and development of these new crops is best controlled. Rooted cuttings of these three species where transplanted into 10-cm pots on 7 Oct. and the plant growth regulator treatments were applied on 19 Oct. 1999. Foliar spray treatments included ancymidol at 66 and 132, daminozide at 2500 and 5000, paclobutrazol at 20 and 40, ethephon at 500 and 1000, and uniconazole at 10 and 20 mg/L. Uniconazole medium drench treatment was applied at 1 and 2 mg/L. Control was a water foliar spray. At harvest, plant height, plant width, number of flowers, pedicle length, stem length, stem node number and internode length, and fresh and dry weights were measured. Uniconazole spray at 20 mg/L reduced plant height and width without affecting the fresh and dry weights of Argyranthemum. Flower number was increased and pedicel length was reduced. The overall plant height and width of Calibrachoa were not reduced with 20 mg /L uniconazole foliar spray, but plant form was improved by decreased internode elongation. Uniconazole foliar spray at 20 mg/L reduced Orthosiphon stem and internode length. Ethephon reduced plant height, plant width, and flower number of all species. Branching and days to flower were increased in Orthosiphon. In all species, daminozide and paclobutrazol were found to be ineffective, while ancymidol spray and uniconazole drench stunted and distorted growth.
Terri W. Starman and Susan L. Hamilton
Many new vegetative annuals are available in the floriculture market today. Their growth habits may be trailing or vigorous and more conducive to hanging basket or container garden culture. Today's gardeners are living busy lives and housing is sometimes confined, with little land on which to garden. These factors all contribute to the popularity of hanging baskets and container gardens. Whereas container garden trials are more common in industry, few universities have added container gardens and hanging baskets to their trial gardens. The objective of the hanging basket and container garden trials at Univ. of Tennessee (UT) initiated in Summer 1999 was to demonstrate and promote this timely trend to commercial growers, landscapers, and the public. An attractive brick walkway and wooden arbor were built by a UT landscape construction class to display the containers and hanging baskets. Several challenges had to be met: funding the purchase of expensive containers; planting and placing the heavy containers in the garden; combining plants within the containers; grouping containers together; labeling plants within the containers; displaying the hanging baskets; maintenance and pruning; and most of all, keeping the containers watered throughout the summer. The color wheel proved to be a useful tool for grouping plants and containers. A handout was developed to guide visitors through the container garden. Despite the challenges, the container garden and hanging basket trials proved to be a successful demonstration and were popular among visitors.
Teresa A. Cerny and Terri W. Starman
Our overall objective was to use DNA Amplification Fingerprinting (DAF) to determine the relationships between Petunia × hybrida and four wild petunia species,P. axillaris, P. inflata, P. parodii, and P. violacea. This research was to optimize the DAF amplification reaction for petunias, check for variability in the fingerprints among different seedlings of the same species and screen primers to be used for Identifying polymorphisms between cultivars of P. × hybrida end the four wild species. Optimization of the DAF procedure was accomplished by varying concentrations of DNA template (O - 10 ng), MgCl2(0 - 10 mM), and primers (0 - 30 μM). Optimum concentrations were found to be 1.0 ng DNA template and 2.0 mM MgCl2. Clearly resolved banding patterns were produced using primer concentrations from 3.0 μM to 30 μM. When separate seedlings of each wild species from the same seed source were fingerprinted, profiles were consistent. Seeds from other sources are presently being collected to investigate variation between sources. Twenty-five heptamer and octomer primers varying in GC content were screened and ten produced clear banding patterns for the Petunia species. These primers have produced polymorphic profiles between the pink-flowering species and the white-flowering species. Several primers have shown distinct polymorphisms between P. axillaris and P. parodii, the two white-flowering species, which have very similar morphological traits. Similarities in the banding patterns have been found between P. × hybrida and these wild species.
Teresa A. Cerny and Terri W. Starman
Seed of five species of petunia and 10 cultivars of Petunia xhybrida were obtained from several sources and plants were fingerprinted using DNA amplification fingerprinting (DAF). Within some species, variable fingerprints were generated between individual plants from the same seed source and/or different sources. Consistencies were found among DAF profiles by bulking the leaf tissue from 10 different plants, but not five plants. Each of 10 octamer primers used during the study revealed polymorphic loci between the species and cultivars. Among the 201 bands produced, 146 (73%) loci were polymorphic and these could be used to distinguish between each of the species and cultivars. Scoring for presence and absence of the amplified bands was used to generate a phylogenetic tree and to calculate the pairwise distances between each of the taxa using parsimony (PAUP) analysis. The tree generated using DAF molecular markers separated P. axillaris from P. parodii (two white-flowered species), and distinguished between the violet-flowered species, P, inflata, P. integrifolia, and P. violacea.