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Coleus (Plectranthus scutellarioides) is an attractive and popular ornamental plant with propagation mainly achieved through vegetative cuttings. For commercial purposes, it is of interest to enhance the speed of establishment while maintaining high quality. Light quality has been shown to influence adventitious root development, so these experiments examined the effect of narrow-bandwidth light treatments on root growth and overall plant quality for seven coleus cultivars with vegetative cuttings in potting soil and one cultivar with shoot tip in vitro cultures onto Murashige and Skoog (MS) agar medium. During the 28 days of the propagation period, the cuttings grown under narrow-bandwidth red light (R; 663.4 nm at peak) more than doubled in the adventitious root number compared with those under blue light (B; 445.7 nm at peak) and green light (G; 530.0 nm at peak) in five cultivars. R light also increased fresh weight of the cuttings by 55.6% more than G light. In comparison, the cuttings grown under G light yielded significantly lower root and shoot dry mass than other light treatments. R light cuttings showed more dry mass content (9.63%) than those under white light (W; 437.4 nm and 559.5 nm at peak) and G light (7.85% and 5.86%, respectively). A positive correlation (R2 = 0.598, P < 0.001) was found between the formation of adventitious roots and gained fresh weight of cuttings. R light made the reddish color of leaves significantly stronger in most cultivars, whereas the cuttings exposed to G light became less vivid compared with other light conditions. When the shoot tips were propagated in vitro onto MS medium, R light treatment initiated the root development more rapidly than other lights, with significantly greater rooting rate (20.0% and 63.6%, respectively) at day 5 and 10. The shoot tips under R light also formed significantly more roots (12.3 per cutting) than those grown under narrow-bandwidth B light (5.8 per cutting). The shoot tips showed browning at an early stage and newly emerged leaves grew very compactly under B light. The combination of red and green light (R+G) increased more than twice as much roots and dry mass compared with W light. In addition, the R+G light led to morphological changes, including larger leaves and longer petioles and internodes than those in other light treatments. The exposure to R+G+B and B light made the shoots very compact for the 28 days of in vitro culture period and significantly increased the chlorophyll contents resulting in dark green leaves.

Despite production of the first domestically produced peach of the calendar year in the United States, the subtropical peach industry faces marketing challenges, particularly with small fruit size. Although important, size is only one aspect of fruit quality, and not inclusive of all possible fruit quality attributes. Thus, this research asked consumers to identify an “ideal” peach given a combination of possible peach fruit quality attributes to help determine their influence on consumer purchase. These attributes were verified with farmers’ market intercept studies. The top attributes that fostered purchase likelihood included flavor, texture, size, and firmness. Psychophysics studies showed that consumers preferred peaches that were sweet, juicy, round, with freestone or semifreestone characteristics, whereas consumers were less likely to purchase peaches with mealy, dry, or meaty textures. Young consumers (ages 18–24) preferred crisp, firm peaches with good flavor, whereas older consumers (ages 51–65) preferred sweet, melting-texture peaches. Farmers’ market intercept studies found consumers (ages 45–65) preferred melting-texture peaches with good flavor that led to increased overall liking. In addition, in the farmers’ market studies, aroma and flavor were important attributes and were highly correlated with overall liking. Objective measurements of total soluble solids (TSS) were not correlated with overall liking, indicating that although the nationwide experiment found consumers desired sweet peaches, other attributes may contribute more favorably to overall liking.

Lantana camara L., a popular nursery and landscape plant, is categorized as an invasive species in Florida, because it produces viable pollen and cross-pollinates with the native species Lantana depressa Small. The invasive potential of L. camara is a challenging issue for the nursery and landscape industry, so sterile non-invasive cultivars are needed to replace fertile invasive ones. This study aimed to determine the ploidy level and male fertility of both commercial L. camara cultivars and breeding lines to identify male-sterile cultivars and assess the effectiveness of sterile triploid production in L. camara. A polyploid series was identified among 32 L. camara cultivars and breeding lines. Male fertility, based on pollen stainability, varied widely among the cultivars/breeding lines. Ploidy level was the most important factor determining L. camara pollen stainability/male sterility. On average, diploids exhibited the highest pollen stainability (64.6%) followed by tetraploids (45.1%), pentaploids (34.6%), and hexaploids (18.0%). Triploids showed the lowest pollen stainability (9.3%), suggesting that generating triploids would be an effective genetic approach to producing sterile L. camara and reducing its pollen-mediated invasiveness. Pollen stainability of triploid cultivars, Balandpawn (LandmarkTM Pink Dawn PP15,516), Lemon Drop, Miss Huff, New Gold, New Red Lantana, Red Butler, Red Spread Lantana, Samson Lantana, and Sunset Lantana was consistently below 10%. A number of triploid cultivars had pollen stainability approaching 20% to 30%, indicating a necessity for careful examination and screening of newly produced triploids to ensure high sterility in selected triploids. Pollen stainability variation was observed within ploidy levels, implying the existence of other genetic and environmental factors that influence the pollen stainability/male fertility of L. camara. Results from this study suggest that there is excellent potential to develop genetically sterile cultivars in L. camara for the U.S. nursery and landscape industry.

Additional index words. blueberry breeding, flavor, fruit quality, Vaccinium corymbosumAbstract.Blueberriesareahigh-valuefruitthathasexperiencedextraordinarygrowthinconsumption in the past decade. Maintaining this growing market requires an un-derstandingofthecurrentmarketanditspotentialforexpansion.Toassaytheimpactof36 specific blueberry sensory and psychological traits on consumer interest, a blueberryfruitqualitystudywasconstructedusingtechniquesthatallowmanyfeaturestobetestedin an analysis by combining specifics from different categories that describe a product.Individual traits that most impact the likelihood of fruit purchase were identified. Sweetand intense blueberry flavor yielded the most positive purchase interest, whereas badtexture attributes such as seediness were the most detrimental to interest. It was alsopossible to define two interest segments within the survey population that shared similarresponses to particular experimentally assayed traits. The larger segment of the samplepopulation (61%) was most interested in the aspects of blueberry flavor, whereas thesecond segment of respondents (39%) was most influenced by health aspects commonlyassociatedwithblueberryfruitconsumption.Bothsegmentsrespondednegativelytobadtexture. This study suggests that breeders and producers should exploit genetic andenvironmental variables that contribute to improved blueberry flavor and that market-ing strategies to sell blueberry cultivars of superior flavor may be appropriate.Blueberries [northernhighbush( Vacciniumcorymbosum), southern highbush (V. corym-bosum hybrids), rabbiteye (V. virgatum), andlowbush (V. angustifolium)] are an economi-cally important small fruit crop in the UnitedStates with 277 million pounds harvestedfor fresh production valued at $850.8 millionU.S. in 2012 (USDA, 2013). Blueberry acre-age continues to increase worldwide in ac-cordance with growing demand for theseantioxidant-rich fruit. Although native toNorth America, breeding programs have de-veloped blueberry cultivars that grow in awider array of climates, allowing productionto flourish in South America, Europe, Asia,and Australia. Global highbush blueberry pro-duction passed the one billion pound mark in2012 and continues to accelerate (Brazelton,2013). Historically, many traits have beenselected for in blueberry breeding programswith producers in mind, including climaticadaptation, yield, mechanical harvest poten-tial, and disease resistance. Conversely, thefruit quality traits of interest to the consumerarewhatshouldultimatelyfuelproductionandprofitability. In recent surveys, only 48% ofU.S. consumers had bought blueberries in thepast 12 months compared with 88% of con-sumers who had bought the highest sellingfruit, bananas (Fresh Trends, 2013). Of the48% of U.S. consumers who purchased blue-berries in the past year, 15% of these con-sumers were reportedly regular buyers ofblueberries (Brazelton, 2013; Fresh Trends,2013). Converting seldom purchasers intofrequent purchasers through product satisfac-tion could have a beneficial impact on theblueberry market. To provide this level ofproduct satisfaction, it is critical to assess theexpectations and desires of the current blue-berry consumer to make sure these parametersare being met. Increasing market penetrationfor the 50% of consumers who did notpurchase blueberries in the past 3 years willbeimportantto drive continuedexpansionofblueberryproductionaswell(Brazelton,2013;Fresh Trends, 2013).Developing a new blueberry cultivar withimproved traits for the producer or consumeris a long-termprocess.From thetimeaninitialcross between two blueberry parents is made,the earliest a resulting progeny is typical-ly considered for release is 10 years. Thisplant must then be marketed to nurseries orfarmerswhomasspropagatetheclones,whichmeansthattheblueberrybreederdesigningtheparental crosses is catering to an industrynearly two decades in the future. Breedersoften work closely with the producers and aretherefore aware of the changing needs offarmers. However, consumer satisfaction withthe end product is influencing new directionsin research and development of horticul-tural crops, encouraging breeder focus ontraits such as improved strawberry (Fragaria·ananassa) flavor (Colquhoun et al., 2012)andflowerfragrance(Levinetal.,2012).Withlengthy breeding cycles, it is critical to em-pirically assay the psychological influences ofconsumer blueberry purchases before com-mitting to years of manipulating traits thatmay not actually affect marketability. Addi-tionally, this information could be used totailor messages directed to the consumerthrough commercial marketing, in advertise-ments, and on packaging.When a consumer encounters a product,multiple attributes of the product may in-fluence their purchase decision. The con-sumer may not necessarily be rational orconsciously aware of the reasoning for thisdecision, and outright asking of the consumerto identify their desires may introduce cog-nitive bias (DellaVigna, 2009; Price and Riis,2012; Redelmeier and Dickinson, 2011).Additionally, attempting to test a high num-ber of variables for psychological impact cancause subject frustration and cognitive bur-den (Park and Lessig, 1981). Both of theseissues can be tackled using modified conjointanalysis and rule-developing experimenta-tion. In this approach, the consumer is pre-sented with sets of three to four individualdescriptive phrases or elements at a time,which reduces the variable load on the re-spondent. Byposingmanyscenarios inwhicha product has a few attributes in differentcombinations, it is then possible to pull outindividually impactful elements from thescheme (Behe, 2006; Behe et al., 1999,2013; Jaeger et al., 2011; Moskowitz, 2012;Moskowitz et al., 2006; Moskowitz andGofman, 2007). This method has been pre-viously implemented to analyze favorablecharacteristics of fresh strawberries andflowers as a tool to guide breeding efforts inthese horticultural crops (Colquhoun et al.,2012; Levin et al., 2012). The strawberrystudy identified sweetness and complex fla-vors as the most important traits to con-sumers, resulting in a large amount of effortand resources that have been devoted tobiochemically characterizing strawberry fla-vor for identification of enhanced qualitycultivars (Schwieterman et al., 2014).This study was conducted as part of anongoing effort to implement consumer-assisted selection in horticultural breedingprograms. Consumer-assisted selection is anapproach to product development that seeksto identify which features are of most impor-tance to the end user, an ambition that can besometimes be diluted along a complex supplychain. We sought to identify which blueberrytraits are of most importance to consumersand may motivate purchase likelihood. Weconducted two consumer-assisted marketing

Previously, when selecting for flavor in the University of Florida southern highbush blueberry (SHB, Vaccinium corymbosum L. hybrids) breeding program, sugar/acid ratios and breeder preference were the only factors considered. A more precise method of evaluating flavor would include volatile compounds that may also contribute to the flavor experience. Therefore, volatile profiles of five SHB cultivars (Farthing, FL01-173, Scintilla, Star, and Sweetcrisp) were compared using gas chromatography–mass spectrometry. All cultivars were harvested on four separate dates within the harvest season, and fruit from each cultivar were also harvested at four developmental stages on the first harvest date. Among the cultivars, soluble solids content and volatile production tended to increase with fruit maturity, whereas titratable acidity decreased. All volatile components were more variable than measures of sugars and acids during the harvest season. Many of the volatiles present varied significantly between harvest dates, resulting in significant genotype × environment interactions during the harvest season. A closer examination of linalool, trans-2-hexenol, trans-2-hexenal, hexanal, and 1-penten-3-ol, five volatile compounds commonly associated with blueberry flavor, showed cultivar, developmental stage, and harvest date differences for each volatile. ‘Star’ experienced the least variation through the harvest period.

The IdeaMap® software suite and the concept of Mind Genomics® were used to analyze which features of a flower product are influential to consumer perception. By presenting online human subjects with combinations of elements that describe a flower product, a database was created to define how individuals perceive distinct components of an overall flower product. This study was conducted with two separate groups of participants, the first provided by a panelist fielding house and the second administered to an undergraduate introduction to plants and gardening class. The fielding house participants represented various demographic groups throughout the United States and the majority was 40 years of age and older. The undergraduate class participants consisted primarily of white, female students between the ages of 18 and 24 years. Each study participant was exposed to a permutation of flower-based elements derived from six categories: flower color, flower shape, consumer health and wellness, flower fragrance, flower purchase location, and flower use. The results of the two studies illustrated which elements of each flower category appealed to different demographics of the population and were used to identify segments of the population that possessed similar mindsets toward elements of interest and disinterest in regard to a flower product. In both the fielding house and student IdeaMap® studies, the highest and lowest interest values were for elements from the flower fragrance category, indicating that floral fragrance is an important aspect of flowers with respect to current and future consumer satisfaction. Three distinct segments were identified in each study with the segments being primarily concerned with elements involving olfaction, visual, and other attributes of a flower product.

Uniconazole was applied as a spray to the surface of container media prior to planting bedding plant plugs. This medium spray was compared to a standard whole-plant spray applied 2 weeks after planting. For petunia (Petunia ×hybrida Vilm.) and coleus (Solenostemon scutellarioides L.) the efficacy of the medium spray was similar to the whole-plant spray. However, for impatiens (Impatiens wallerana Hook. f.) and vinca [Catharanthus roseus (L.) G. Don.] the medium spray had greater efficacy than the whole-plant spray. Increased concentrations of uniconazole in the medium spray decreased plant height; however, the effect of higher concentrations was greater in a medium with out pine bark compared to a medium with pine bark as a component. In the above experiments, uniconazole was applied in a volume of 200 mL·m-2. In a test where spray volume varied, there was a negative linear relationship between plant height and spray volume. Chemical name used: (E)-(+)-(S)-1-(4-chlorophenyl)-4,4-dimethyl-2-(1,2,4-triazol-1-yl)-pent-1-ane-3-ol (uniconazole).

A broccoli (Brassica oleracea var. botrytis L.) seedling bioassay was used to measure paclobutrazol activity and distribution in two growing media following drench or subirrigation applications. The bioassay exhibited a saturation-type response curve for paclobutrazol concentrations up to 1000 μg·L-1 in solution and 100 μg·L-1 in the media. The concentration of paclobutrazol required to achieve one-half of the maximum observed bioassay activity was 3-fold as high in bark-based commercial potting medium as in a peat-based medium. Less than 2% of applied paclobutrazol leached out during the drench application despite the collection of up to 50 mL of leachate per 120 mL of the solution (1000 μg·L-1) that was applied per 15-cm pot. Immediately following drench application, paclobutrazol concentrations in both media were highest in the uppermost 2.5 cm and decreased downward. By 3 weeks after treatment, drench-applied paclobutrazol had moved into lower depths. Distribution of paclobutrazol was limited to the bottom 2.5 cm of media when applied as a subirrigation soak. Chemical name used: (±)-(R*,R*)-β-[(4-chlorophenyl)methyl]-α-(1,1-dimethyl)-1H-1,2,4-triazole-1-ethanol (paclobutrazol).

Three experiments were conducted to evaluate media component effects on paclobutrazol activity. In Expts. 1 and 2, a broccoli (Brassica oleracea var. botrytis L.) seedling bioassay was used to compare the activity of paclobutrazol at six concentrations (0-0.32 mg·L-1). Results from Expt. 1 indicated that an average of 4-, 5-, and 10-fold higher concentrations were required in old composted pine bark, fresh pine bark, and composted pine bark samples, respectively, to achieve the same activity observed in sphagnum peatmoss (peat) samples. Activity in coir was similar to that in peat while activity in vermiculite and perlite was greater than that in peat. Activity in a fibrous peat sample was greater than in two less-fibrous peat samples. Results from Expt. 2 indicated that paclobutrazol activity was reduced more in the fine (4 mm) fractions. In Expt. 3, petunia {Petunia hybrida Vilm. `Madness Red') was grown in a mixture of either 60% composted pine bark: 0% peat or 0% composted bark: 60% peat. The paclobutrazol concentration required to achieve the same size control was 14 times higher in the former mixture than in the latter. Thus, media components differ greatly in their influence on paclobutrazol activity and the bioassay procedure may serve as a useful tool for predicting media-paclobutrazol interactions. Chemical name used: (±)-(R*,R*)-β-[(4-chlorophenyl)methyl]-α-(l,l-dimethyl)-lH-l,2,4-triazole-l-ethanol (paclobutrazol).

The biological effects of ethylene on plant growth and development have been documented for over a century. Ethylene profoundly influences many aspects of development, both pre- and postharvest (Abeles et al., 1992). Spoilage losses ascribed to ethylene effects are significant for both food and ornamental crops. The major agricultural losses associated with ethylene have spurred research on methodologies for control of its synthesis and action. We have been particularly interested in two physiological processes associated with high economic value: fruit ripening and flower senescence. This article addresses biotechnological approaches to control these two processes. There are multiple strategies for controlling ethylene synthesis and response. We will limit our discussion to those with which we have personal experience. Although we will not cover all of the potential target genes, the strategies outlined here apply to the other gene targets. Fruits in which ripening is controlled by ethylene are generally referred to as climacteric. Examples include tomato, melon, mango, papaya, and banana. Our efforts have focused on tomato as a model for several reasons. The tomato is relatively easy to genetically modify via Agrobacterium tumefaciens‐mediated transformation. It has a broad base of physiological, biochemical, and genetic research on which to build. It is also a highly important commercial crop, being the number one valued vegetable produced in Florida (Lucier, 2000). Partly because of its economic importance, much research has been focused on the molecular biology of tomato ethylene synthesis and perception. Like climacteric fruits, a subset of flowers produce and senesce in response to ethylene. One of the best understood of these species is petunia. A petunia flower will produce large amounts of ethylene within hours of pollination. Exposure of flowers to ethylene induces rapid loss of turgor that leads to corolla wilting within 1 to 2 d. Like tomato, petunia is readily transformable and has an excellent foundation of genetic, physiological, and biochemical research. All of these factors make it an excellent model system for genetic manipulation.

Experiments were conducted with four kinds of flowering plants to compare one-time vs. continuous application of paclobutrazol in subirrigation water. When a crop reached the stage at which it required growth regulator treatment, four concentrations of paclobutrazol were applied via subirrigation either one-time or continuously until the crop was terminated. Based upon regression equations, concentrations resulting in 30% size reduction for one-time applications of paclobutrazol were 0.01 mg·L-1 for Begonia ×semperflorens-cultorum `Cocktail Gin', 0.09 mg·L-1 for Impatiens wallerana Hook. `Super Elfin White', 0.2 mg·L-1 for Dendranthema ×grandiflorum (Ramat.) Kitamura `Tara', and 2.4 mg·L-1 for Petunia ×hybrida Vilm.-Andr. `Plum Crazy'. Respective optimal values for continuous application were 0.005, 0.02, 0.06, and 0.4 mg·L-1. Increasing the concentration for continuous application had a greater effect on paclobutrazol efficacy than did increasing the concentration for a single application. In a trial with impatiens `Super Elfin Salmon Blush', the paclobutrazol concentration was reduced 0%, 25%, 50%, 75%, or 100% (single application) for each successive subirrigation event following an initial application of 0.1 mg·L-1 of paclobutrazol. The 50%, 75%, and 100% reduction treatments provided similar levels of size control. Dilution was more important when the reduction rate was less than 50%. Chemical name used: (±)-(R*,R*)-β-[(4-chlorophenyl)methyl]-α-(1,1-dimethyl)-1H-1,2,4-triazole-1-ethanol (paclobutrazol).

Contamination of recirculated subirrigation water with growth retardants poses a potential problem for growers. Eight concentrations of ancymidol or paclobutrazol ranging from 0 to 100 μg·L-1 (0 to 1000 μg·L-1 for petunia) were supplied constantly in subirrigation water to potted plants to identify critical levels at which plant growth is affected. Concentrations of ancymidol resulting in 20% reduction in plant size relative to untreated controls were 3, 10, 98, 80, and 58 μg·L-1 for Begonia ×semperflorens-cultorum Hort. `Gin', chrysanthemum (Dendranthema ×grandiflora Kitam.) `Nob Hill', Impatiens walleriana Hook f. `Super Elfin Coral', Petunia ×hybrida Hort. Vilm.-Andr. `Madness Pink', and Salvia splendens Sell ex Roem. & Schult. `Red Hot Sally', respectively. Respective values for paclobutrazol were 5, 24, 17, 390, and >100 μg·L-1. The results provide useful information for managing potential growth retardant contamination problems or for applying growth retardants in subirrigation water. Chemical names used: α-cyclopropyl-α-(4-methoxyphenyl)-5-pyrimidinemethanol (ancymidol); (±)-(R*,R*)-β-[(4-chlorophenyl)methyl]-α-(1,1-dimethyl)-1H-1,2,4-triazole-1-ethanol (paclobutrazol).

Six cultivars of potted rose (Rosa ×hybrida L.) plants were evaluated for shipping stress-induced leaf chlorosis during holding at 8, 16, or 28C for 2, 4, or 6 days. `Meijikatar' showed more leaf chlorosis than the similar `Meirutral' at the higher simulated shipping temperatures and longer durations. Plants of `Meijikatar' were treated before simulated shipping with BA, TZ, or Promalin at 0, 25, 50, or 100 mg cytokinin/liter each, then paper-sleeved and stored in the dark in fiberboard boxes at 16C for 5 days. Plant quality 5 days after removal from storage was better with BA at 50 or 100 than at 0 mg·liter–1. All cytokinin-treated plants showed less leaf chlorosis than controls. Benzyladenine at 50 or 100 mg·liter–1 reduced leaf chlorosis when compared to all TZ treatments. There were no differences among treatments in the number of etiolated shoots per plant. Chemical names used: N-(phenylmethyl)-1H-purin-6-amine (benzyladenine, BA); trans-zeatin (TZ); gibberellic acid (GA4+7) + BA (Promalin).

In an effort to modify and study leaf senescence, we have produced several different transgenic petunia lines with altered leaf senescence phenotypes. Using two promoters from senescence-associated genes (sag12 & sag13) fused to the isopentenyl transferase (IPT) gene, which catalyzes the rate-limiting step of cytokinin production, we have produced transgenic petunia plants with delayed lower leaf senescence. We have observed that apparent “leaky” expression of IPT gives rise to plants with other morphological alterations such as increased branching habit and decreased root formation. Plants with delayed leaf senescence phenotypes were selected and bred to produce progeny that were evaluated in greenhouse experiments. Breeding characteristics, horticultural performance and reproduction of these plants will be discussed in terms of potential commercial benefits and limitations. Using the sag12 promoter to drive expression of the knotted (KN1) gene, we have also been able to engineer petunia plants with delayed lower leaf senescence. Initial progeny evaluations of sag12-KN1 petunias will also be discussed.

Dendranthema×grandiflorum (Ramat.) were grown in either a peat-based or pine bark—based medium and drenched with growth retardants at a range of concentrations to generate dose : response curves. The effect of ancymidol, paclobutrazol, and uniconazole on stem elongation was less in the pine bark—based than in the peat-based medium. Generally, the concentrations required to achieve the same response were 3- to 4-fold as high in the pine bark—based medium as in the peat-based medium. However, chlormequat was slightly more active in the pine bark—based medium than in the peat-based medium. Chemical names used: α-cyclopropyl-α—(4-methoxyphenyl)-5-pyrimidinemethanol (ancymidol); (±)-(R*,R*)-β-[(4-chlorophenyl)methyl]-α-(1,1-di methyl)-1H-1,2,4-triazole-1-ethanol (paclobutrazol); (E)-(RS)-1-(4-chlorophenyl)-4,4-dimethyl-2-(1H-1,2,4-triazol-1-yl)pent -l-en-3-ol (uniconazole); 2-chloroethyltrimethylammonium chloride (chlormequat).

Petunia × hybrida `Electric Purple' plants, genetically transformed (Selecta Klemm Co.) via Agrobacterium tumefaciens to constitutively express the Cauliflower Mosaic Virus 35S promoter (CaMV35S) fused to two separate Arabidopsis c-repeat binding factor cDNAs (CBF3 & CBF4), were utilized to evaluate water relations. Non-stressed plants followed a classical stomatal conductance pattern, with maximum conductance between 1000 hr and 1400 hr. CBF3 and CBF4 plants showed an increase in transpiration rates and a decrease in stomatal resistance at 1230 hr, compared to `Electric Purple'. Transpiration rates (per unit leaf area) were similar in CBF3 and `Electric Purple' plants, but CBF4 plants were 12% less than `Electric Purple'. Xylem water potentials at visible wilt were between –1.4 and –1.5 MPa and there were no significant differences between line or irrigation treatment. A fourth experiment observed differential plant responses to stress cycles. Under non-stress irrigation conditions, CBF4 plants showed an increase in stomatal resistance and a decrease in transpiration rate compared to `Electric Purple' plants. There were no differences in the xylem water potential at visible wilt for the first and third stress cycles, but, for the second cycle, xylem water potentials at wilt were –1.9, –1.7 and –1.4 Mpa for CBF4, `Electric Purple' and CBF3 plants, respectively. CBF3 and CBF4 plants showed small differences in performance as compared to `Electric Purple' and under mild stress conditions as imposed in these experiments apparent heterologous overexpression of the Arabidopsis CBF3 & 4 transgenes may not be sufficient for conferring drought tolerance in petunia.

In this study, the temporal and spatial regulation of putative ethylene receptor genes was examined during ethylene and pollination-induced flower petal abscission of zonal geranium (Pelargonium × hortorum L.H. Bailey). We used the Arabidopsis thaliana ETR1 gene as a heterologous probe to isolate two full-length cDNA clones, GER1 and GER2, from an ethylene-treated geranium pistil cDNA library. Both cDNAs share a high degree of DNA sequence similarity to ETR1, and examinations of deduced amino acid sequences indicate that the proteins encoded by each gene have the conserved ethylene binding and response regulator domains found in ETR1. Experiments focused on determining the temporal regulation of these genes revealed that both genes are expressed in geranium florets much earlier than when the florets become responsive to ethylene treatment, which is sufficient to cause petal abscission in 1 hr. Both genes are expressed in pistils throughout floret development. Experiments focused on determining the spatial regulation of these genes revealed that both genes are expressed at moderate levels in leaves, pistils, anthers, and petals, and are expressed at very low levels in roots. Preliminary evidence suggests that GER2 is transcriptionally regulated by ethylene in pistils after exogenous ethylene treatment. Currently, the transcriptional regulation of these genes in pistils after pollination is unknown.

It has traditionally been recommended to cut flower stems underwater to reduce blockage and improve water uptake, although little scientific information relates this practice to vase life. The purpose of our study was to evaluate the benefit of this processing technique on quality and longevity of several cut flowers species. Stems were either cut dry or cut wet under deionized water with a stainless steel blade and placed into vases containing a commercial floral preservative. Water samples were obtained from the cutting tank over time during stem processing for bacteria counts. Stems were maintained at 2 °C at 10 μmol·m–2·s–1 (12 h/day). The results were variable from shipment to shipment, possibly due to differences in stem quality or cutting water quality. In most cases, cutting underwater had no effect on longevity of alstroemeria, chrysanthemums, gerbera daisy, roses, or snapdragons. However, in a few instances, cutting underwater improved longevity slightly. Cutting stems underwater was consistently effective in increasing longevity 2-4 days for carnations. Bacteria counts in the cutting tank water after 500 stems were processed were 6/34 × 106 propagules/mL and increased to 1.00 × 107 propagules/mL after 1000 stems. The increase in bacteria decreased leaf quality in roses and reduced the number of snapdragon flowers that opened, but did not affect longevity. In gerberas, however, longevity decreased 2 days. A high concentration of bacteria in the cutting water may effect quality and longevity of many cut flower species and may negate any benefit in cutting stems underwater.

Postproduction evaluation trials have been developed in North America and Europe to test postproduction performance of potted roses from individual growers. The results of the trials have been compiled on the “Roses On The Web” Website (www.parade.dk). Roses on the WEB is a cooperative project between Poulsen Roses ApS, Denmark, the Danish Institute of Agricultural Sciences, and the Univ. of Florida. The goal of the Website is to provide growers participating in the evaluation trials a quick and easy way to obtain results on the postproduction quality of their roses. Plants receive 4 days of simulated transport, sleeved in a box in darkness at 16 °C. After transport, plants are maintained at 20 °C at 8 μmol·m–2·s–1 for 12 hours/daily. Relative humidity is maintained at 55% ± 5%. To determine quality, several parameters are recorded at day 0 (day of arrival), 11, 18, 22, and 28. The recordings include the number of open and damaged flowers and buds, percentage of damaged leaves, and the presence of disease and pests. Based on the results of all the measurements, each plant is given a postproduction rating or index, indicating quality. Results from each trial are tabulated and stored on the Website. Growers are able to view their results by entering a password. Growers can evaluate their quality over time and are also able to compare their quality with other growers. Many quality problems are manifested in the postproduction environment and can often be directly related to incorrect greenhouse conditions and/or cultural practices. “Roses On The Web” is a tool that provides quick, up-to-date information that can be crucial to the success of a grower. Differences in quality were found based on grower, time of year and variety.

The traditional use of poinsettias has been as potted plants. A new poinsettia variety, `Winter Rose Dark Red', is performing well as a cut flower, lasting 2 to 3 weeks. Various postharvest handling procedures were examined, including stem processing methods at harvest, storage and transit conditions, as well as handling practices at the wholesale, retail, and consumer levels, to determine the best handling practices to maximize quality and longevity. At harvest, traditional latex controlling techniques, such as dipping stems in 95% ethanol for 10 min and burning or boiling stem tips were tested. Stems wilted faster when dipped in ethanol or burned. The woody nature of the stem contains little latex compared to traditional varieties; thus, no latex-controlling methods are needed or beneficial. After harvest, there was no benefit found in hydrating stems in a commercial hydration solution compared to plain water. Transport and/or storage conditions between 10 to 15 °C for 3 to 4 days maximized longevity. Chilling injury occurred when transported at 4 °C. Leaves and bracts wilted when stored dry in a box, but recovered within 12 to 24 h when stored for 2 days. Leaves abscised after exposure to short-term wilting but no bract abscission occurred. Storing stems in a 10% bleach solution prevented wilting and reduced bacterial growth. Bracts were sensitive to mechanical injury during transit, resulting in bruising lesions on the bracts, which increased sensitivity to bract edge burn. Stems declined faster when maintained in a floral preservative compared to water during the consumer phase.

Production and postproduction factors were examined to evaluate effects on postproduction performance and longevity of several varieties of potted African violets, carnations, chrysanthemum, cyclamen, gerbera, Hiemalis begonia, hibiscus, hydrangea, kalanchoe, and lisianthus. Various N rates (150–600 ppm) and fertilizer termination 2 to 3 weeks prior to flowering were evaluated. Chrysanthemums, hydrangea, and lisianthus had better quality and longevity at N rates ranging from 200 to 300 ppm, while all other crops performed best at 150 ppm N. Terminating fertilizer had no effect on longevity or quality of carnation, gerbera, Hiemalis begonia, hydrangea, or kalanchoe, while chrysanthemum and cyclamen had a significant increase in longevity when terminated. Lisianthus had an increase in quality and longevity when fertilizer was continued to the end of production. Shipping at the proper bud developmental stage significantly influenced flower opening and longevity in the postharvest environment. Lisianthus and hydrangea need to have at least 75% of the buds fully opened, while carnations, chrysanthemum, cyclamen, and kalanchoe need at least 25% to 50% open. Hiemalis begonia, a very long-lasting potted plant, tolerated a range of 10% to 75% open flowers at shipping. Optimum transport temperature and transport duration varied for each crop. Generally, transporting for 3 days at 2 to 7 °C was best for carnation, chrysanthemum, and gerbera, while transporting at 7 to 12 °C was best for cyclamen, Hiemalis begonia, hydrangea, kalanchoe, and lisianthus. Hibiscus performed best when transported at 18 °C. Longevity and quality were maximized when maintained at 18 to 21 °C at 14 μmol·m–2·s–1. Differences in variety performance was a major factor in postproduction performance.

In some species of bedding plants, rapid hypocotyl elongation during germination makes size control in plug production difficult. Commercial growers often start applying growth regulators as cotyledons are expanding or after the first true-leaves are expanding. Using `Bonanza Spry' marigolds, we evaluated applying paclobutrazol at sowing and after 3 and 6 days. Sprays at 30 mg·L–1 in a volume of 0.2 L·m–2 or 3 mg·L–1 in 0.6 mg·L–1 applied at sowing reduced hypocotyl elongation by 25% and produced more compact plugs. In a second study, plugs of `Double Madness Rose' petunia, `Showstopper Orange' impatiens, `Wizard Rose' coleus, and `Cooler Rose' vinca were grown in 10-cm pots with a growing medium that did not contain pine bark. Uniconazole was sprayed in a volume of 0.2 L·m–2 onto the surface of the medium before planting at concentrations of 25%, 50%, and 100% of the label's recommended concentration for each crop. An additional treatment was uniconazol applied 2 weeks after planting at the label concentration. All early applications reduced final plant size compared to the nonsprayed plants. For impatiens, the early application at 25% of the label concentration produced plants similar to the spray at 2 weeks after planting. For the other crops, the 50% treatment prodcued plants similar to the spray after planting. The early applicaiton of growth regulators offers the industry an additional stradagy to use for controlling the growth of vigorous bedding plant crops.

Rosa × hybrida `Meijikatar' plants were fertilized on weekdays with Hoagland's solution at 100, 200, or 300 mg·liter-1 nitrogen. Prior to simulated shipping, plants were treated with benzyladenine at 0, 25, 50, or 100 mg a.i.·liter-1. Plants were subsequently paper sleeved and stored in cardboard boxes in darkness at 16 C for 5 days. On the day of harvest, plant height and number of flowers per plant were not affected by production nitrogen level. After removal from simulated shipping, total chlorophyll was increased in the lower leaves of plants grown at higher nitrogen rates and treated with higher rates of benzyladenine. Three and five days after removal from simulated shipping, the least percent leaf chlorosis was observed on plants treated with higher rates of cytokinin, but there was no effect of production nitrogen regime.

Four poinsettia cultivars were grown in glass greenhouses in Gainesville, Fla., in the Fall 1997 to evaluate differences in floral initiation and subsequent development. Three means of regulating photoperiod were 1) natural days 2) long-day lighting to 6 Oct. and then natural days (lights out) 3) long-day lighting to 6 Oct., and then short-day conditions by black cloth for 15 h (black cloth). At 2-day intervals, sample meristems were collected and examined for initiation of reproductive development. Average minimum and maximum temperatures during the first two weeks of October were 22 and 29 °C, respectively, with an average temperature of 25.3 °C. The overall average temperature was 23.2 °C from planting to anthesis. Differences in anthesis dates among cultivars were primarily due to time to initiation vs. rate of development. Under natural days, `Lilo' initiated first on 8 Oct. and `Freedom', `Peterstar', and `Success', followed by 6, 8, and 18 days, respectively. Lights out resulted in `Lilo' initiating 17 Oct., followed by `Freedom', `Peterstar', and `Success' initiating 7, 12, and 15 days later, respectively. Differences between cultivars in time of initiation was reduced under black cloth, where `Lilo' initiated 14 Oct., followed by `Freedom' 2 days later, and `Peterstar' and `Success' 7 days afterward. Initiation was positively correlated to visible bud and anthesis. First color was positively correlated to initiation and visible bud, with the exception of `Lilo'. Growth room studies conducted using various high temperatures and photoperiods indicated similar trends.

A broccoli seedling bioassay was used to compare the activity of paclobutrazol applied at six concentrations to 20 media component samples mixed 1:1 (v:v) with vermiculite. Results indicated that 4-, 5-, and 10-fold higher media paclobutrazol concentrations were required in old composted pine bark, fresh pine bark, and composted pine bark samples, respectively, to achieve the same activity observed in sphagnum peatmoss. Paclobutrazol bioassay activity in coir was similar to the activity observed in peat, while activity in vermiculite and perlite was greater than in peat. In a second trial, paclobutrazol activity was reduced more in the fine (4 mm) fractions. In a third trial, petunias grown in a 60% composted pine bark:0% peat mix required a »14-times higher drench paclobutrazol concentration to achieve the same size control as petunia grown in a 0% composted bark:60% peat mix. It was concluded that media components differed greatly in their influence on paclobutrazol activity and that the bioassay procedure might serve as a useful tool for predicting media–paclobutrazol interactions.

Salvia (Salvia splendens F.), vinca (Catharanthus roseus L.), and pansy (Viola × wittrockiana Gams.) were examined to determine efficacy of growth retardants for inhibiting stem elongation of seedlings in the plug stage and after transplanting to 10-cm pots. Studies on salvia showed plugs sprayed with single applications of ancymidol at 10 or 20 ppm, paclobutrazol at 30 or 60 ppm, or daminozide/chlormequat tank mix at 2500/1500 ppm inhibited plug elongation by 17% to 22%. Pansy plugs were sprayed either once or twice with ancymidol at 5, 10, or 15 ppm. Number of applications was statistically significant with two applications reducing elongation by an average of 35%, whereas a single application resulted in a 23% average reduction. Ancymidol concentration was significant in reducing stem elongation with increasing rates in pansy; however, the concentration and application time interaction was not significant. In both pansy and salvia, plant size at flowering was similar to controls after transplanting. Vinca plugs were sprayed with ancymidol at 5, 10, or 15 ppm either the 3rd week, 4th week, or both weeks after sowing. As ancymidol concentrations increased, plug height decreased, and the concentration effect was greater week 3 than at week 4. Two applications of ancymidol was most effective in retarding stem elongation (36%) followed by one spray the 3rd week (29%) and one spray during week 4 (20%).

We are studying the horticultural performance of two model plant systems that carry a mutant gene that confers ethylene-insensitivity: Never Ripe tomatoes and petunia plants transformed with the mutant etr1-1 gene isolated from Arabidopsis thaliana. Having two model systems to compare side-by-side allows us to determine with greater certainty ethylene's role at different developmental stages. Presence of the mutant etr1-1 gene in transgenic petunias was determined using three techniques: PCR analysis, the seedling triple response assay (inhibition of stem elongation, radial swelling of stem and roots, and an exaggerated apical hook when grown in the dark and in the presence of ethylene), and the flower wilting response to pollination, which is known to be induced by ethylene. Flowers from ethylene-insensitive petunias took almost four times as long to wilt after pollination as wild-type plants. It is well known that fruit ripening in Never Ripe tomato is inhibited, and a similar delayed fruit ripening phenotype is observed in petunia plants transformed with etr1-1. In an effort to maintain ethylene-insensitive petunia plants by vegetative propagation, we observed that the rate of adventitious root formation was much lower with transgenic plants than in wild-type plants. In subsequent experiments on adventitious root formation in Never Ripe tomato, we observed the same result. Therefore, while ethylene-insensitive tomato and petunia plants appear phenotypically normal for many characters, other factors are altered by the presence of this mutation. The fact that these changes are present in two model systems helps to define the role of ethylene perception in plant growth and reproduction.

Trials involving growth retardants applied in subirrigation water were conducted to evaluate the potential for this method of application and to determine critical concentrations for production of several floriculture crops. Eight concentrations of paclobutrazol or ancymidol ranging from 0 to 0.1 mg·liter–1 were applied continuously (from planting) to five crops. Based upon regression equations, paclobutrazol concentrations resulting in 20% size reduction were 0.005, 0.024, 0.017, >0.1, and >0.1 mg·liter–1 for begonia, chrysanthemum, impatiens, petunia, and salvia, respectively; for ancymidol, respective concentrations were 0.003, 0.01, 0.10, >0.1, and 0.058 mg·liter–1. A second set of trials compared the efficacy of a one-time vs. continuous application of paclobutrazol via subirrigation starting at 2 to 3 weeks after planting. For begonia, a one-time subirrigation application of 0.01 mg·liter–1 paclobutrazol resulted in 30% size reduction, while 0.003 mg·liter–1 applied continuously resulted in 20% size reduction. For impatiens, a one-time subirrigation application of 0.1 mg·liter–1 paclobutrazol resulted in 31% size reduction while 0.03 mg·liter–1 applied continuously resulted in 40% size reduction.

Ethylene-regulated gene expression is being studied in several plant systems, but the exact mechanism of ethylene action during plant development and senescence is poorly understood. When geranium (Pelargonium Xhortorum) flowers are exposed to 1 μ1/L of ethylene gas for 1 hour, petals begin to abscise within 60-90 minutes from the start of treatment, The rapidity of the response implies that it must be very direct. We now demonstrate that ethylene acts at the level of message accumulation. We have constructed a cDNA library from mRNA isolated from ethylene-treated geranium gynoecia. Ethylene-induced clones have been isolated by differential screening of this library with cDNA probes synthesized from ethylene-treated and untreated geranium gynoecia mRNA. Identification and characterization of these clones will be discussed.