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Karen R. Harris, W. Patrick Wechter, and Amnon Levi

conservation of these markers among the genera of the Cucurbitaceae, sequence-tagged site (STS) primers were developed from a clone representing each WRGA class. Nucleotide sequences of all WRGA groups were aligned using AliBee and WRGA-STS primers were

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Custódia M.L. Gago, José A. Monteiro, and Ma Helena M. Rodrigues

The effect of NAA [16.5 mg/L or 500 mg/L sprayed once at end-of-production from two different sources: wettable powder (Fruitone) and sodium hydroxide solution (Sigma)], STS (0.5 mM sprayed once at end-of-production and 0.4 mM sprayed every 15 days after bracts started to be apparent) and ethanol 50% (v/v) solution, sprayed twice: at end-of-production and immediately after simulated transport) were tested using two types of completely randomized experiments. At the end-of-production plants were placed for 3 days under simulated transport conditions (171°C, no light) and then placed under interior conditions (211°C and 11 mol·s–1·m–2 of cool-white fluorescent light 12 h/day). Every other day during post-production the number of bracts not completely developed (ED), as well as the number of completely (CD) developed, bracts remaining in the plants were assessed. Among the post-production treatments tested, NAA (500 mg/L) and STS (applications every 15 days during production) + NAA (16.5 mg/L) were the most-efficient treatments. Ethanol and STS (one single application) did not control bract abscission efficiently and did not increase plant longevity. Plants treated with NAA abscise more not completely develop bracts than completely developed bracts. Use of NAA in potted bougainvillea requires fully developed bracts at end-of-production.

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Julie P. Newman, Michael S. Reid, and Linda Dodge

Commercial formulations of silver thiosulfate (STS) were evaluated for their efficacy in promoting postharvest longevity of gypsophila. Argylene, Chrysal AVB, Chrysal OVB, Oasis Dry Flower Conditioner, Rogard RS, and Silflor were compared to the anionic STS complex and to Physan plus sucrose. Flowers were pulse treated, then placed overnight at 2° C in Physan plus sucrose. Flowers treated with Rogard RS, Chrysal OVB, and Physan were held continuously in the solution. Overnight treatments of STS were compared to short pulses at higher concentrations. To simulate the effect of shipment, treated flowers were packed in boxes, then held either for 48 hours at room temperature (12-18° C) or for 60 hours in a range of ethylene concentrations. Individual stems were then placed in Physan plus sucrose. The number of open flowers, buds, and dead flowers was determined on each stem at various intervals. All products effectively extended the display life of gypsophila except Rogard RS and Chrysal OVB. Although overnight treatments with STS formulations were not as effective as pulse treatments, their convenience could warrant commercial use.

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Diana L. Dostal, Nancy Howard Agnew, Richard J. Gladon, and Jack L. Weigle

Exposure to exogenous ethylene (C2H4) caused corolla abscission of New Guinea impatiens (Impatiens × hawkeri `Sunfire'). Abscission varied with time of exposure and C2H4 concentration. Ethylene at ≥ 1 μl·liter-1 and exposure times of 4 or more hours caused 80% to 100% corolla abscission. Simulated shipping of untreated control plants caused ≈ 65% corolla abscission. Plants pretreated with silver thiosulfate (STS) and (aminooxy)acetic acid (AOA) and subsequently exposed to simulated shipping were not different from one another, and both treatments reduced corolla abscission to ≈ 20% when applied at 1.0 mm. Plants pretreated with STS and exposed to `exogenous C2H4 showed 0% abscission, whereas plants pretreated with AOA showed no reduction in abscission when compared with control plants.

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Margrethe Serek and Arne Skytt Andersen

Miniature rose (Rosa hybrida L. cv. Victory Parade) plants were treated with AOA, BA, or STS before simulated shipment and display in an interior environment. Although AOA-treated plants lasted slightly longer than nontreated plants, their postproduction quality, evaluated as floral longevity, bud drying, and bud abscission, was not as satisfactory as that of STS- or BA-treated plants. In this ethylene-sensitive cultivar, BA treatment was almost as satisfactory as STS treatment. Flowers that opened in the greenhouse before shipping lasted longer than those that opened in the interior environment room. STS and BA treatments increased the longevity of both flower types. However, these treatments did not eliminate the difference between flowers that opened before or after transport simulation. Chemical names used: aminooxyacetic acid (AOA); benzyladenine (BA); silver thiosulfate (STS).

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Genet Teshome Mekuria, Margaret Sedgley, Graham Collins, and Shimon Lavee

A sequence-tagged site (STS) was developed to identify a genetic marker linked to resistance to olive leaf spot caused by the pathogen, Spilocea oleaginea (Cast) (syn. Cycloconium oleaginum Cast.). The STS was based on a randomly amplified polymorphic DNA (RAPD) marker of about 780 base pairs (bp) linked to olive leaf spot resistance. Several primer pairs were developed to flank the sequence, and one pair produced the expected polymorphism between resistant and susceptible individuals tested, and was used as an STS marker. This primer pair was tested against parents and 34 individuals from a population segregating for resistance to olive leaf spot, and 12 commercial olive (Olea europaea L.) cultivars showing various levels of resistance to the disease. The STS marker was present in 71.4% of the parents and progeny that were designated as resistant, and was absent in 87% of the parents and progeny showing susceptibility. These primers were also able to distinguish cultivars such as `Koroneiki' and `Leccino', that are reported to show resistance to olive leaf spot, from `Barouni' and `Mission', that are reported to be susceptible. This is the first report of a STS marker for olive, and its use will assist greatly in screening olive progeny for resistance to leaf spot in breeding programs.

Open access

Timothy A. Prince, Maria S Cunningham, and James S. Peary

Abstract

The poststorage and post-shipping quality of Lilium longiflorum Thunb. ‘Nellie White’ plants sprayed with silver thiosulfate (STS) complex or phenidone was observed in a simulated interior environment. Bud abortion and foliar chlorosis increased while floral longevity declined with increasing storage period from 0 to 4 weeks in the dark at 2°C. One to 3 days of simulated, boxed shipment at 23° subsequent to 3 weeks storage at 2° further increased foliar chlorosis but did not influence bud abortion or floral longevity. Whole plant STS sprays (0.5 to 2.0 mM Ag) prior to harvest reduced storage-induced bud abortion and increased floral longevity, but did not reduce foliar chlorosis. Ethephon application to plants that had been stored for 3 weeks at 2° induced bud abortion and abnormal floral development. STS application (1.0 mM Ag) prior to storage reduced ethephon-induced disorders. Preharvest whole plant sprays of phenidone decreased bud abortion on stored and nonstored plants but did not influence floral longevity. Uptake of phenidone and STS through cut petioles enhanced ethylene production during opening of excised lily buds. Ethylene production increased while respiration declined during senescence of excised buds. STS did not reduce but did delay the peak of ethylene production during senescence of lily flowers. Chemical names used: 1-phenyl-3-pyrazolidone (phenidone); (2-chlorethyl)phosphonic acid (ethephon).

Open access

Mary K. Hausbeck, Christene T. Stephens, and Royal D. Heins

Abstract

Selected seed-propagated hybrid geranium (Pelargonium × hortorum Bailey) cultivars were evaluated for resistance to crown and root rot caused by Pythium ultimum Trow in the presence or absence of foliarly applied STS, a petal-shattering preventative that has been demonstrated to increase plant death due to P. ultimum. Plants were evaluated for resistance to plant death, plant stunting, and flower delay by comparing plant growth in P. ultimum-infested medium with plant growth in a noninfested medium. Although immunity to P. ultimum was not identified in the 42 cultivars screened, resistance appeared to be present and may provide a valuable source of germplasm for further screening and subsequent hybridization for resistance.

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Titus M. Kyalo and H. Brent Pemberton

Rooted liners of Rosa cvs. Meijikatar and Meirutral were potted into 11 cm pots and placed into growth chambers. One chamber provided 14 hours of light with 30C/21C (day/night) air temperature (HTLD) and another chamber provided 8 hours of light with 21C/17C (day/night) air temperature (LTSD). PPF was 725 μmoles m-2 s-1 in both chambers. When plants were established, they were pinched and forced to flower. Simulated shipping for 4 days at 16C in darkness resulted in a shorter shelf-life when placed in an interior environment at 21C with a continuous PPF of 30 μmoles m-2 s-1 and compared to non-shipped plants. In addition, LTSD grown plants exhibited a shorter shelf-life than HTLD grown plants. When Meirutral plants were sprayed to runoff 24 hours prior to shipping, 2 mmolar (aminooxy)acetic acid (AOA) increased the shelf-life to the same length as the non-shipped plants and 2 mmolar silver thiosulphate (STS) increased the shelf-life to longer than the non-shipped plants. However, AOA did not increase shelf-life over that of shipped plants for Meijikatar whereas STS increased the shelf-life to that of the non-shipped plants.

Open access

Thomas H. Boyle, Daniel J. Jacques, and Dennis P. Stimart

Abstract

Plants of Rhipsalidopsis gaertneri [Regel] Moran ‘Crimson Giant’ were given continuous 14-hr long-days (LD), provided by 8-hr daylight plus 6-hr incandescent (Inc) irradiation; continuous 8-hr short-days (SD), provided by daylight; 2, 4, 6, or 8 weeks SD, then LD; or 2, 4, 6, 8 weeks LD, then SD. All plants receiving continuous LD or 2, 4, 6, or 8 weeks SD then LD flowered, whereas some or all plants in other photoperiod regimes failed to flower. Earliest and most prolific flowering occurred in response to 4, 6, or 8 weeks SD then LD. In a second experiment, plants previously given 8 weeks of 8-hr daylight (SD) were transferred to one of the following photoperiods: 12-, 14-, 16-, or 20-hr (8 hr daylight plus = to 12-hr Inc irradiation); 8-hr daylight plus 4-hr Inc night interruption (NI); or 8-hr daylight (SD). All plants receiving photoperiods of 12 to 20 hr or 4-hr NI flowered. Days from start of photoperiod treatments to visible flower buds was inversely related to duration of the Inc irradiation period, with a 4-hr NI comparable to 16-hr day. Days required for visible flower buds to complete development (flower expansion) were largely unaffected by duration or timing of Inc irradiation. Application of BA delayed flowering but more than doubled the number of flower buds per flowering apical phylloclade. Flower bud abortion was increased and both flower fresh weight and flower diameter were diminished by BA. Application of STS did not reduce flower bud abortion on BA-treated plants, but increased the percentage of apical phylloclades flowering. Chemical name used: N-(phenylmethyl)-lH-purin-6-amine (BA), silver thiosulfate (STS).