DNA amplification fingerprinting (DAF) was used to evaluate the genetic relationships among 11 cultivars of poinsettia (Euphorbia pulcherrima Willd.). Amplification was with 10 octamer oligonucleotide primers that generated 336 DNA bands. Thirty-one percent of the bands were polymorphic and distinguished among cultivars. Genetic relationships were evaluated by cluster analysis, and the resulting dendrogram closely agreed with published cultivar relationships. Arbitrary signatures from amplification profiles (ASAP) were further used to characterize two cultivars, `Nutcracker Red' and `Peterstar Red', that were previously found to be genetically and morphologically similar, as well as five cultivars in the “Freedom” series. The DAF products generated with arbitrary octamer primers were reamplified with mini-hairpin decamer primers in these experiments. The ASAP profiles were complex and yielded a total of 231 bands, 38% of which were polymorphic and capable of distinguishing each Freedom cultivar. Five of the eight primer combinations distinguished `Nutcracker Red' from `Peterstar Red'. Thus, closely related cultivars of poinsettia can be separated using new and improved molecular fingerprinting protocols.
Terri Woods Starman, Xiangrong Duan, and Shane Abbitt
Terri Woods Starman, Estella Auerswald, and P.T. Gibson
The objective of the research was to determine the effectiveness of uniconazole on Hypoestes phyllostachya Bak. cv. Pink Splash and to compare the effect and persistence of uniconazole with chlormequat and daminozide for limiting stem elongation during post-greenhouse, low light conditions. Uniconazole at 5.0 mg·liter-1 reduced all measured plant dimensions to the same degree as chlormequat at 2500 mg· liter-l when both chemicals were applied twice as foliar sprays at a two week interval. These treatments resulted in the most compact and aesthetically pleasing 0.4-liter potted plants. However, this uniconazole treatment was not as persistent in postproduction low light conditions as chlormequat. By the fifth week under low light conditions, only the highest drench concentration of uniconazole tested (0.10 mg a.i. per pot) remained the same height as chlormequat treated plants.
Amy J. MacKenzie, Terri Woods Starman, and Mark T. Windham
Trichoderma harzianum Rifai, a fungus that controls soilborne pathogens, can enhance growth of several vegetable and floriculture crops. Zero, 5, or 25 g of T. harzianum (isolate T-12) peat–bran amendment was added per kilogram medium in an effort to enhance the rooting of four chrysanthemum [Dendranthema ×grandiflorum (Ramat.) Kitamura] cultivars, two considered easy to root (`Davis' and `White Marble') and two considered hard to root (`Dark Bronze Charm' and `Golden Bounty'). Adding the T. harzianum amendment at both rates tested increased root and shoot fresh weights during 21 days of rooting, relative to the control. Supplementary treated cuttings were transplanted into nontreated growing medium after 21 days. Midway between transplant to flowering, increases in height, shoot dry weight, and root fresh and dry weight were detected in `Dark Bronze Charm' with T-12, relative to the control; increases in height, shoot fresh and dry weight, and number of nodes were detected in `Golden Bounty' with T-12. By this time, there were no detectable differences in `Davis' or `White Marble'.
Terri Woods Starman, Teresa A. Cerny, and Tracy L. Grindstaff
Height control and flowering responses to uniconazole spray or drench treatments were measured for `Multibloom Scarlet' and `Red Elite' geranium (Pelargonium ×hortorum L.H. Bailey). Total plant height of both cultivars was reduced proportionately to the height of a 10-cm container when the uniconazole drench concentration was 0.025 mg a.i./pot. Used as a spray, uniconazole was not as effective in restricting total plant height of either cultivar. Foliage height was shortened more than inflorescence height. Inflorescence diameter was decreased with increasing uniconazole drench concentrations. Sprays did not affect inflorescence diameter of either cultivar. Uniconazole effect on days to flower varied with cultivar and application method. Chemical name used: (E)-(S)-1-(4-chlorophenyl)-4,4-dimethyl-2-(1,2,4-triazol-1-yl)-pent-1-ene-3-ol (uniconazole).
Terri Woods Starman, Millie S. Williams, and James E. Faust
The objective was to determine the optimum number of plants and the number of pinches required to market a basket for hanging basket production using alternative floriculture species. The number of plants per pot varied from one to four, and the number of manual pinches per basket ranged from 0 to 2. Several species were evaluated in spring of 1996 and heat tolerance was assessed throughout the summer. Plugs (50–95 plugs per flat) were transplanted into 25-cm hanging baskets in a 22/18°C (venting/night temperature set points) glasshouse. Three to four plants were necessary for Scaevola aemula `Fancy Fan Falls' and Evolvulus glomeratus `Blue Daze' to produce a marketable basket. One plant per pot was sufficient for Abutilon hybrid `Apricot', Portulaca oleraceae `Apricot', and Tibouchina `Spanish Shaw' without sacrificing quality; however, an additional 1 to 3 weeks production time was needed in comparison to the four plants per pot treatment. Abutilon and Portulaca required one pinch, while Tibouchina did not require pinching. All plants × pinch combinations produced quality baskets with Sutera cordata `Mauve Mist' and Diascia hybrid `Ruby Fields'; therefore, production methods should be based on growers' scheduling and cost analysis. Abutilon, Evolvulus, Portulaca, Scaevola, and Tibouchina performed well in hanging baskets throughout the summer. Two species in the trial, Orthosiphon stamineus `Lavender' and Tabernamontana coronaria, displayed upright growth habits and would be best for uses other than hanging basket production.
Terri Woods Starman, Teresa A. Cerny, and Amy J. MacKenzie
The productivity and profitability of annual and perennial field-grown specialty cut-flower species were evaluated for the southeastern United States. Data were collected on 20 annuals and 20 perennials in 1992 and on 19 annuals and 19 perennials (10 in their second year of production) in 1993. Productivity and profitability were based on yield and stem length measurements. Yield was expressed as total number of stems harvested. Income per 30-cm center was predicted from the number of stems ≥41 cm long that were harvested. Some species had high yields but stem lengths were too short for most market outlets. Among those species that combined high yield with long stems and resulted in high profitability without major pest or postharvest problems were the perennials Achillea filipendulina Lam., Echinacea purpurea (L.) Moench, Liatris spicata (L.) Willd., and Platycodon grandiflorus Jacq. A. DC. and the annuals Antirrhinum majus L., Cosmos bipinnatus Cav., Scabiosa atropurpurea L., and Zinnia elegans Jacq. Low overhead of field production coupled with productive species could prove to be profitable.
Linda F. Meer, James E. Faust, and Terri Woods Starman
An experiment was conducted to determine the effect of plant growth regulator, application concentration, and time of application on five cultivars of Kalanchoe (Stromboli, Majestic, Heirloom, Keepsake, and Revelry). Kalanchoe cuttings were propagated in 5.2-cm-diameter containers under a short-day photo-period, then placed into a greenhouse maintained at 20C. Spray applications of paclobutrazol (25 or 50 ppm) and uniconazole (1 or 5 ppm) were made prior to visible flower bud (VB), after VB, or before and after VB. Across all cultivars and spray application dates, paclobutrazol applied at 25 and 50 ppm reduced total plant height by 20% and 29%, respectively, while uniconazole applied at 1 and 5 ppm reduced total plant height by 16% and 24%, respectively. Plant height was reduced by 13% with the pre-VB application, 23% with the post-VB application, and 32% with the pre- and post-VB applications. In general, the greater the treatment effectiveness at reducing plant height, the greater the increase in time to flower. For example, a post-VB Bonzi (50 ppm) application caused a 6-day delay in time to first open flower. With the appropriate plant growth regulator application, all five Kalanchoe cultivars tested could be used for commercial production in 5.2-cm-diameter pots.
David C. Annis, Paul T. Gibson, and Terri Woods Starman
The objective of this study was to investigate the influence of photoperiod and 0, 1, 5, or 10 applications at weekly intervals of GA3 foliar sprays at 500 mg·liter–1 on growth and flowering of Craspedia globosa `Drumstick' Benth. Long days (LD) hastened flowering and increased the number of flowers per plant. Short days (SD) increased foliage height and foliage fresh and dry weights. Foliage and total plant heights increased and days to bud and secondary inflorescence width decreased linearly as GA3 application frequency increased. Chemical name used: (1α,2β,4aα,4bβ,10β)-2,4a,7-trihydroxy-1-methyl-8-methylen egibb-3-ene-1,10-dicarboxylic acid 1,4a-lactone (gibberellic acid, GA3).