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Paclobutrazol substrate drenches at 0, 1, 2, 3, or 4 ppm were compared to a 2,500 ppm daminozide foliar spray standard in two finishing seasons (fall 2015 and spring 2016) and at two application stages for plant size control and improved market quality of ‘Bright Red with Light Eye' Gerbera daisy (Gerbera jamesonii Hook. f. ‘Bright Red with Light Eye') in 12.7cm (5 in) pots. Stage 1 was when the majority of plants had roots to the bottom of the substrate, and stage 2 was 2 weeks later. A consumer preference survey assessed purchasing preference when plants had two or three open flowers. Plant size index, foliage height, peduncle length, flower diameter, and quality rating at first flower decreased linearly while days to first flower increased quadratically with increasing paclobutrazol concentration, regardless of stage or season. Paclobutrazol applications delayed flowering, and decreased flower diameter and flower and bud counts, but these differences were small and not considered of practical importance. Based on quality rating at first flower and survey results, a 1 or 2 ppm paclobutrazol drench produced the most marketable plants in fall, and 0, 1, 2, or 3 ppm produced the most marketable plants in spring.Index words: plant growth retardant, B-Nine, Bonzi, greenhouse productionChemicals used in this study: B-Nine (daminozide) [butanedioic acid mono (2,2- dimethylhydrazide)] and Bonzi (paclobutrazol) [(±)-(R*,R*)-β-[(4-Chlorophenyl)methyl]-α-(1,1- dimethylethyl)-lH-1,2,4-triazole-1-ethanol]Species used in this study: ‘Bright Red with Light Eye' Gerbera daisy (Gerbera jamesonii Hook. f. ‘Bright Red with Light Eye')

A study was conducted to determine how seedling development stage at transplanting from plug flats into small pots affected growth and flowering of two commonly grown bedding plants. Seeds of Showstar® medallion flower and ‘Las Vegas Pink’ globe amaranth were sown in 392-cell flats on five dates for each of two experimental runs before transplanting into 8.9 cm (3.5 in) cubic pots. At transplanting of both species, plant height, node count and shoot dry weight increased as days from sowing to transplanting increased and there was no visible cessation in shoot growth due to root restriction. Time to first flower from transplanting decreased linearly with both species in both runs, except with medallion flower in the second run, as time from sowing to transplanting increased. In contrast, time to flower of both species from sowing increased linearly as time from sowing to transplanting increased. However, the magnitude of the increase or decrease in time to flower differed between the two runs indicating that other factors, most likely light intensity and duration, besides node counts were affecting time to flower. Globe amaranth height and growth index and medallion flower growth index at first flower decreased as time from sowing to transplanting increased, whereas medallion flower height was not affected by time from sowing to transplanting.

A study was conducted to evaluate dikegulac sodium (dikegulac) and benzyladenine (BA) as branching agents on landscape trees during production. Common among the six species in this two-year study was an increase in new shoot development following the application of dikegulac. Relative to shoot counts of nontreated plants, trees treated with a single foliar application of 800 to 3200 ppm of dikegulac had an increase in shoot numbers of 29 to 107% in Japanese maple, 75 to 158% in red maple, 67% in redbud, 50 to 65% in bald cypress, and 56 to 103% in black gum. Nontreated plants of green ash formed only one or two lateral shoots in 2011, whereas dikegulac-treated green ash had 10 to 12 new shoots. In 2012, green ash treated with 200 to 800 ppm of dikegulac developed 100 to 150% more new shoots than nontreated green ash. Foliage of all species, except Japanese maple, was injured to varying degrees by dikegulac, but the injury dissipated over the growing season. BA promoted increased shoot development only in bald cypress, and canopies of that species were visually fuller and more compact than those of bald cypress treated with dikegulac.

Herbaceous perennials were screened for increased branching and flowering in response to foliar sprays of cyclanilide (CYC), a plant growth regulator with cytokinin-like activity. Coreopsis verticillata ‘Creme Brulee’ (‘Creme Brulee’ coreopsis) and Rudbeckia fulgida ‘Goldsturm’ (‘Goldsturm’ coneflower), the only two species that responded positively to CYC, were used in subsequent experiments evaluating CYC concentration, method of application, and stage of plant development at application. Foliar sprays of 25 to 100 ppm CYC promoted increased shoot development, flowering, and plant width of coreopsis and coneflower, although flowering was delayed. Applying foliar sprays to both species when they were vegetative resulted in similar or more new shoots and flowers than an application when plants exhibited early signs of approaching flowering or at both stages. Increases in shoot counts from the application of substrate drenches of CYC to coreopsis and coneflower generally were less than from foliar sprays, while flower counts either decreased with increasing CYC concentration (coreopsis) or were unaffected (coneflower). Species used in this study: Coreopsis verticillata L. ‘Creme Brulee’ (‘Creme Brulee’ coreopsis), Lantana ×hybrida hort. ‘New Gold’ (‘New Gold’ lantana), Pennisetum setaceum (Forssk.) Chiov. ‘Rubrum’ (purple fountain grass), Perovskia atriplicifolia Benth. (Russian sage), and Rudbeckia fulgida Aiton ‘Goldsturm’ (‘Goldsturm’ coneflower).

A study was conducted to determine if there were synergistic effects from applying two plant growth regulators (PGRs), cyclanilide (CYC) and benzyladenine (BA), with cytokinin properties on Rhaphiolepis sp. (L.) Lindl. ‘Conor’ and ‘Snow White’ (Indian hawthorn), Rhododendron L. ‘North Lake Beauty’ (azalea), and Ilex crenata Thunb. ‘Sky Pencil’ (Japanese holly) during nursery production. Foliar applications of 100 or 200 ppm CYC promoted new shoot development in all species, whereas 2500 ppm BA either had no effect or suppressed shoot development, except in one of two experiments when shoot development was promoted in holly. With no species was there a synergistic effect on shoot development from combining the two PGRs, even when both PGRs individually promoted new shoot development in holly. Indian hawthorn and holly developed transient symptoms of toxicity in response to CYC, BA, and CYC + BA combinations that had dissipated by the end of the growing season and had no lasting effects on plant quality.

Cyclanilide (CYC) is a bioregulator that promotes the development of lateral shoots in ornamental and fruit tree crops, potentially reducing the need for mechanical pruning during nursery production. In 2006, three foliar applications of 200 ppm CYC applied at a 1, 2, or 3 week application interval increased shoot counts of ‘Diana’ sasanqua camellia, ‘Sky Pencil’ holly, and ‘Snow White’ Indian hawthorn when compared to pruned and unpruned controls. However, application interval had no effect on shoots counts in holly or camellia and minimal effect in Indian hawthorn. Foliar injury to Indian hawthorn was severe, regardless of application interval. In 2007, three applications of 50 or 100 ppm CYC were applied at a 1, 3, or 6 week interval to ‘Sky Pencil’ holly and ‘Snow White’ Indian hawthorn. At 120 to 150 days after initial treatment (DAIT), shoot counts in both species increased with application interval, and all CYC-treated plants formed more new shoots than controls. Transitory injury to new growth of Indian hawthorn, although not quantified, appeared to increase as application interval decreased. At 120 DAIT foliar injury was no longer evident in Indian hawthorn. At 180 DAIT quality rating of both cultivars increased with CYC application interval and was greater than that of controls, and CYC-treated plants were visibly more dense and compact.

Cyclanilide (CYC), a plant growth regulator with cytokinin-like properties, was applied as a substrate drench to containerized woody ornamentals to determine its effects on plant growth. At 70 days after treatment (DAT) in 2005, drench applications of 50 to 1,000 ppm CYC had increased shoot development 7 to 74% for ‘Alabama Beauty’ sasanqua camellia (Camellia sasanqua ‘Alabama Beauty’), 63 to 205% for small anisetree (Illicium parviflorum), 21 to 74% for ‘Snow White’ Indian hawthorn (Rhaphiolepis indica ‘Snow White’), and 266 to 626% for ‘Sky Pencil’ holly (Ilex crenata ‘Sky Pencil’), when compared to control plants. Shoot counts the following spring, 270 DAT, increased from 16 to 101% for sasanqua camellia, 42 to 158% for small anisetree, 121 to 241% for Indian hawthorn, and 33 to 167% for ‘Firepower’ nandina, when compared to control plants. At 30 DAT foliar injury to sasanqua camellia, Indian hawthorn, and small anisetree increased with CYC concentration, and application of 500 or 1,000 ppm CYC resulted in severe injury or death of small anisetree and ‘Snow White’ Indian hawthorn. At 75 DAT in 2006, drench application of 25 to 100 ppm CYC had increased shoot counts of Eleanor Taber™ Indian hawthorn from 100 to 218%, when compared to controls, and quality ratings were highest at 130 DAT in plants drenched with 50 ppm CYC, although foliar injury ratings increased with CYC concentration at 75 and 130 DAT. At 60 DAT in 2007, application of 10 to 40 ppm CYC had increased shoot counts for ‘Snow White’ Indian hawthorn and ‘Sky Pencil’ holly 100 to 182% and 22 to 78%, respectively, and 96 to 171% and 30 to 63%, respectively at 90 to 110 DAT. In both species, quality ratings at 160 DAT increased with increasing CYC concentration. Single CYC drench applications were more persistent than previously reported single spray applications, effective at lower concentrations, and promoted shoot production in a species not responsive to single or multiple spray applications (Nandina domestica).

A study was conducted to determine the effects of pruning on plant response to cyclanilide (CYC), a bioregulator that promotes lateral branching of fruit trees and selected woody nursery crops. In April 2004, non-pruned ‘Elizabeth Ann’ Japanese camellia (Camellia japonica L.) and small anisetree (Illicium parviflorum Michx. ex Vent.) received a single foliar application of 0, 25, 50, 100 or 200 ppm CYC, while the same species received a foliar spray of 0, 50 or 100 ppm CYC following uniform pruning. In June 2006, a single foliar application of 0, 100 or 200 ppm CYC was made to plants of ternstroemia (Ternstroemia gymnanthera Thunb.), ‘Sky Pencil’ holly (Ilex crenata Thunb.) and ‘Jennifer’ azalea (Rhododendron L.) that were either not pruned or uniformly pruned before CYC treatment. At 30 and 60 days after treatment (DAT), non-pruned, CYC-treated plants formed more shoots than pruned CYC-treated plants, however quality ratings at 120 DAT were generally higher in plants pruned prior to CYC treatment. In a third experiment, the effects of 200 ppm CYC on branching of ternstroemia, ‘Sky Pencil’ holly, ‘Jennifer’ azalea and ‘Snow White’ Indian hawthorn were ascertained when applied at three stages of lateral shoot development following pruning: immediately after pruning [developmental stage 1 (DS 1)], when new shoots were 1.3 to 2.6 cm (0.5 to 1 in) in length (DS 2), or when new shoots were 2.6 to 5.1 cm (1.0 to 2.0 in) in length (DS 3). At 60 days after pruning (DAP), shoot counts in ternstroemia and ‘Sky Pencil’ holly treated at DS 3 and ‘Snow White’ Indian hawthorn treated at DS 2 were greater than those of pruned controls. Shoot counts in ‘Jennifer’ azalea were not affected by plant developmental stage at the time of CYC application. Relatively minor injury was evident at 60 and 120 DAP in all species except ‘Jennifer’ azalea, and was most pronounced in ternstroemia and ‘Sky Pencil’ holly treated at DS 3 and in ‘Snow White’ Indian hawthorn treated at DS 2. Quality ratings were similarly high for plants of all species and treatments, except in ‘Sky Pencil’ holly in which quality ratings of plants treated with CYC at DS 1 or DS 3 were higher than those of pruned controls.

Foliar sprays of 10, 15, or 20 ppm paclobutrazol followed by a second application of 50 ppm were applied to ‘Bravo Lavender’ and ‘Celebrity Blue’ petunias and ‘Salvador Red’ and ‘Vista Red’ salvia during production to determine their effects on plant growth, flowering and market quality during production, simulated shipping, and while in a simulated retail environment. Paclobutrazol effectively suppressed shoot growth and enhanced market quality of all cultivars during production, while minimally or not affecting time to first flower. Growth suppression and enhanced market quality continued through simulated shipping and the period plants were in the retail environment. While in the simulated retail environment, plants were exposed to six or seven wilt/hydration cycles. The % wilted plants of all four cultivars previously treated with paclobutrazol during production was much less than that of the controls: ‘Bravo Lavender’ petunia, 21 vs. 67%; ‘Celebrity Blue’ petunia, 10 vs. 88%; ‘Salvador Red’ salvia, 15 vs. 69%; and ‘Vista Red’ salvia; 13 vs. 74%.

An experiment was conducted to determine the effects of several widely used plant growth retardants on plant size and flowering of Achillea × ‘Coronation Gold’. Plants in 10 cm (4 in) pots were grown in a greenhouse and treated with B-Nine at 0, 2550, 5100, or 7650 ppm; Cycocel at 0, 767, 1534, or 2301 ppm; B-Nine/Cycocel at 0, 1275/1534, 2550/1534, or 3825/1534 ppm; Sumagic at 0, 11, 22, 33, 44, or 55 ppm; Bonzi at 0, 32, 64, 96, 128, or 160 ppm; or Cutless at 0, 40, 80, or 120 ppm as a spray 1 week after vernalization. B-Nine, Cycocel, B-Nine/Cycocel, Sumagic, Bonzi, and Cutless reduced shoot height and growth index by 36 and 26%, 39 and 27%, 61 and 41%, 75 and 52%, 52 and 36%, and 75 and 51%, respectively, with the highest rate of each. B-Nine, Cycocel, B-Nine/Cycocel, and Sumagic, but not Bonzi or Cutless, increased the number of days to open inflorescence by 3-5 days with increasing rate. Sumagic, Bonzi, and Cutless reduced inflorescence diameter by up to 15, 18, and 14%, respectively but not B-Nine, Cycocel, or B-Nine/Cycocel. The highest quality ratings of 2.8 to 3.0 were found with B-Nine/Cycocel at 3825/1534 ppm, Sumagic at 22 and 33 ppm, and Bonzi at 64 ppm. Differences between the results in this study and earlier studies implicate the possible impact of differences in experimental environments, container size, or stage of development when the plant growth retardant treatments were applied.

Multiple weekly or biweekly applications of 0, 100, 200 or 300 ppm cyclanilide (CYC), a bioregulator effective in stimulating branching of apple and cherry trees and select woody ornamental shrubs, were applied foliarly to eight species or cultivars of woody landscape shrubs, five of which showed increased branching in response to treatment. Shoot number increases were concentration and species dependent, and compared to untreated controls, branching at 60 days after first treatment (DAFT) with three weekly applications of 100 to 300 ppm CYC in 2005 increased from 1400 to 1900% in ‘Brandy's Temper’ sasanqua camellia, 114 to 175% in ‘Sky Pencil’ holly, 385 to 458% in ‘Foster’ holly, 166 to 335% in Eleanor Taber™ Indian hawthorn, and 1885 to 2230% in ‘Olivia’™ Indian hawthorn. In 2006, branching 60 DAFT with three biweekly applications of 100 to 300 ppm CYC increased 34 to 73% in ‘Foster’ holly, 268 to 413% in Eleanor Taber™ Indian hawthorn, and 2540 to 4440% in Olivia™ Indian hawthorn. Plant size often decreased with increasing CYC concentration, but not in all species or cultivars. Injury to new foliage of ‘Brandy's Temper’ camellia and ‘Sky Pencil’ and ‘Foster’ holly occurred in 2005, and to new foliage of Eleanor Taber™ and Olivia™ Indian hawthorn in both 2005 and 2006, however symptoms were transient and no longer evident by 120 DAFT. Quality of treated responsive plants at 120 DAFT was usually higher than that of untreated plants, and CYC-induced treatment effects generally persisted until the end of the growing season.

This investigation was conducted to determine the plant growth retardant type, application method, and rate required to produce a marketable greenhouse pot plant of Coreopsis verticillata L. ‘Moonbeam’. Pruned plants in 10 cm (4 in) pots received growth retardant treatments in two experiments consisting of one application of ancymidol or paclobutrazol medium drenches at 0, 2, 4, or 6 ppm; daminozide spray at 0, 2550, 5100, or 7650 ppm; paclobutrazol spray at 0, 12, 24, 36, 48, or 60 ppm; flurprimidol spray at 0, 25, 50, 75, 100, 150, or 200 ppm; or maleic hydrazide at 0, 360, 720, 1080, 1440, or 1800 ppm in the first experiment and sprays of daminozide at 0, 2550, 5100, or 7650 ppm; paclobutrazol at 0, 60, or 120 ppm; daminozide/paclobutrazol combinations at 0, 2550/16, 2550/32, 2550/48, or 2550/64 ppm, chloromequat at 0, 767, 1534, or 2301 ppm; or daminozide/chloromequat combinations at 0, 1275/1534, 2550/1534, 3825/1534, or 5100/1534 ppm in the second experiment. In the first experiment, there was a linear decrease in shoot height, growth index, and lateral shoot length with increasing rates of ancymidol and paclobutrazol drenches and flurprimidol sprays while daminozide decreased growth quadratically. There was a linear increase in shoot height and lateral shoot length with increasing rates of maleic hydrazide but no effect on growth index. Only daminozide and maleic hydrazide increased the number of days from treatment to flower with increasing rates. Quality ratings increased with increasing rates of ancymidol, daminozide, and flurprimidol with the highest ratings found at the two highest rates of daminozide and flurprimidol. Paclobutrazol spray did not affect the parameters measured. In the second experiment, chloromequat spray did not affect the parameters measured but when combined with increasing rates of daminozide, linearly decreased shoot height, growth index, and lateral shoot length while increasing the number of days to flower. Daminozide alone resulted in a quadratic change in growth index and lateral shoot length while linearly increasing the number of days to flower but with no effect on quality rating. The higher rates of paclobutrazol than were used in the first experiment decreased shoot height and lateral shoot length with no effect on growth index, the number of days to flower, or quality rating. Overall, the best quality ratings and the most compact plants resulted from spray applications of daminozide at 5100 ppm or 7650 ppm and flurprimidol at 150 ppm or 200 ppm, however flurprimidol is not currently registered for application to greenhouse crops but a newer product, Topflor, has the same active ingredient and greenhouse crop labeling.

Inconsistencies have been reported in the role of vernalization and photoperiod on growth and flowering of Leucanthemum x superbum Bergmans ex J. Ingram cultivars. Five cultivars were used to determine the effects of vernalization and photoperiod on days to flower, shoot height, growth index, flower shoot number, and quality rating. Plants received 0, 3, 6, 9, or 12 weeks of vernalization time (VER) at 4.4C (40F) and afterward were placed under either natural short days (SD) or night-interrupted lighting (NIL) in a greenhouse. ‘Becky’ showed an obligate requirement for NIL to flower with 100% of plants flowering under NIL and 0% of plants flowering under SD regardless of VER. Vernalization for 6 weeks before NIL increased shoot height, growth index, flower shoot number, and quality rating but the fewest days to flower occurred after 12 weeks of VER. ‘Silver Princess’, ‘Snow Cap’, ‘Snow Lady’, and ‘Summer Snowball’ showed a facultative requirement for NIL to flower. Plants under NIL flowered earlier, were larger, had more flower shoots, and had a higher overall quality rating than plants under SD. Shoot height and growth index were highest under NIL after 3 and 6 weeks of VER, flower shoot number was highest after 3 to 9 weeks of VER, but days to flower was least after 12 weeks of VER. Therefore, NIL after 3 or 6 weeks of VER would maximize plant size and quality for practical application in the cultivars studied but result in more DTF when compared to 12 weeks of VER.

In 2000 and 2004, cultivars of Hemerocallis were treated with foliar applications of 2500 or 5000 ppm benzyladenine (BA) for 1, 2, 3, 4 or 5 consecutive weeks. In both years, BA increased ramet production of all cultivars although treatment response was cultivar dependent. In 2000, an increasing number of BA applications resulted in ‘Lavinia Love’ and ‘Beguine’ forming 1.6 to 3.2 and 0.7 to 1.1 more ramets, respectively, than control plants at 9 weeks after initial treatment (WAT), regardless of concentration. Increasing BA concentration increased ramet formation by up to one ramet in ‘Beguine’ and up to 3 ramets in ‘Lavinia Love’ at 9 WAT, regardless of the number of applications. At 9 WAT in 2004, increasing weekly applications of BA increased ramet formation in ‘Dainty Deb’ from a mean of 1.3 ramets with one application to a mean of 3.0 ramets with five applications, and in ‘Sarah Sikes hybrid’ from 0.5 ramets with one application to 2.1 ramets with five applications, regardless of concentration. Compared to control plants, ‘Dainty Deb’ increased ramet production by 1.9 ramets and 2.3 ramets at 9 WAT in 2004 when treated with 2500 ppm and 5000 ppm BA, respectively, regardless of the number of applications. Compared to untreated controls, ‘Sarah Sikes hybrid’ formed 1.1 and 1.3 more ramets when treated with 2500 ppm and 5000 ppm BA, respectively.

Coreopsis verticillata ‘Moonbeam’ and Rudbeckia fulgida ‘Goldsturm’ were sprayed with tank mixes of B-Nine and Cycocel in all combinations of 0, 2500, 5000 or 7500 ppm B-Nine and 0, 1000, 1500 or 2000 ppm Cycocel. B-Nine was more effective in controlling height of both cultivars than Cycocel or B-Nine/Cycocel tank mixes. B-Nine alone suppressed height of coreopsis 26-52% (over all concentrations and all data collection dates), in contrast to a 17–41% height suppression when B-Nine was combined with Cycocel. Cycocel alone suppressed height of coreopsis 6–16% over all concentrations and data collection dates. B-Nine suppressed height of rudbeckia 20–40% over all data collection dates, while Cycocel suppressed height of rudbeckia only in the last two weeks of data collection (10 and 12% at weeks 8 and 9, respectively). Tank mixes applied to rudbeckia were not as effective as B-Nine alone for height suppression. Flowering of coreopsis was delayed 6 days by B-Nine and 12–14 days by tank mixes of B-Nine and Cycocel; Cycocel accelerated flowering up to 5 days when used alone. Flowering of rudbeckia was delayed up to 9 days with increasing B-Nine concentrations but was unaffected by Cycocel alone or tank mixes of B-Nine/Cycocel. No phytotoxicity was observed at the concentrations used.

Studies were conducted in 1999 and 2000 to determine effects of Atrimmec (dikegulac-sodium) applied at 0, 2340 or 4680 ppm and pruning just prior to Atrimmec application (1999 only) on shoot length and shoot number of Lonicera × heckrottii ‘Goldflame’ (Goldflame honeysuckle). When Atrimmec was applied in June 1999, shoot lengths were suppressed in non-pruned plants 21–24% 2 weeks after treatment (WAT), 16–19% 4 WAT, 16–17% 8 WAT, and 15–16% 10 WAT compared to control plants. Shoot length was suppressed 933% in pruned plants from 2 through 10 WAT, with increased suppression from concurrent pruning evident in control plants 2 WAT, and for plants treated with the higher Atrimmec rate 2 through 10 WAT. Following 10 WAT, increasing Atrimmec rate suppressed shoot length linearly and independent of pruning, 15–21% 12 WAT and 14–21% 14 WAT. When Atrimmec was applied in April 2000, shoot length of non-pruned plants was suppressed quadratically by increasing Atrimmec rate with suppression at the highest rate (4680 ppm) of 17% 2 WAT, 24% 4 WAT, 21% 6 WAT, 22% 8 WAT, and 20% 10 WAT. In 1999, Atrimmec and pruning affected shoot number independently. There was a linear and later a quadratic increase in shoot number with increasing Atrimmec rate of 44–122% 6 WAT, 18–68% 8 WAT, and up to 24% 10 WAT. Shoot number of non-pruned plants was greater than pruned with mean increases of 8 shoots 6 and 8 WAT and 5 shoots 10 WAT. Increasing rates of Atrimmec increased shoot number in the 2000 study up to 62% 2 WAT, 47–106% 4 WAT, 57–67% 6 WAT, and 9-27% 8 WAT.

A study conducted in 2000 determined effects of two rates of Cutless and B-Nine/Cycocel tank mix and initial plant height on vegetative growth and flowering of Canna x generalis ‘Florence Vaughan’. Canna lily responded independently to plant growth retardant (PGR) treatment and initial plant height. Cutless suppressed vegetative height consistently up to 34% at the lower rate (25 ppm) and up to 41% at the higher rate (50 ppm) throughout the study, regardless of initial plant height. At first and second flower, increasing rates of Cutless suppressed vegetative height about 36% and 35–40%, respectively, and first and second flowering heights, 39–52% and 36–47%, respectively, with minimal effect on time to flower. Height suppression from B-Nine/Cycocel treatments was less than from Cutless with the greatest suppression, 12%, occurring at first flower. Differences in vegetative height among short, intermediate, and tall plants were most significant at treatment, decreased thereafter, and were not present 60 days after treatment (DAT). The number of days to first and second flower was affected by initial plant height with shorter plants flowering 10 to 15 days later than taller plants. At first flower, vegetative height of the initially tall plants was greatest, followed in succession by plants intermediate and short at treatment. However, by second flower, vegetative heights of plants, which were initially short and intermediate in height, were greatest, followed by tall plants. At first flower, flowering heights of all plants were similar and at second flower, flowering heights of the initially tall plants were slightly less [5–6 cm (1.9–2.3 in)] than those of intermediate and short plants.

A study conducted in 1999 and 2000 determined the effects of B-Nine/Cycocel (daminozide/chlormequat chloride) tank mixes at 2500/1500, 5000/1500 (1999 only), and 7500/1500 parts per million (ppm) and Cutless (flurprimidol) at 50, 100, and 150 ppm on shoot length and shoot number of pruned and non-pruned Lonicera × heckrottii ‘Goldflame’ (Goldflame honeysuckle). In 1999, B-Nine/Cycocel suppressed shoot lengths of pruned plants linearly throughout the study 18–30% 2 weeks after treatment (WAT), 16–28% 4 WAT, 24–35% 6 WAT, 24–34% 10 WAT, and 19–33% 14 WAT compared to untreated controls. Similar shoot length suppression was observed in non-pruned plants from B-Nine/Cycocel treatments in 2000 with shoots 8–24% (2 WAT), 7–24% (4 WAT), 7–20% (6 WAT), 5–19% (10 WAT), and 5–20% (14 WAT) shorter than those of untreated controls. Cutless was ineffective in suppressing shoot length of Goldflame honeysuckle in either experiment, but did increase shoot number compared to controls 6 through 14 WAT in 1999. B-Nine/Cycocel treatments did not consistently increase shoot number in either study.

The effects of 15 to 45 ppm Cutless (flurprimidol), 2500/1500 to 7500/1500 ppm B-Nine/Cycocel tank mixes (daminozide/chlormequatchloride), and 20 to 60 ppm Sumagic (uniconazole) on the vegetative growth and flowering of Canna x generalis ‘Florence Vaughan’ were determined during container nursery production and landscape establishment. Vegetative heights 30 and 60 days after treatment (DAT) and vegetative and inflorescence heights at first and second flower were suppressed by all plant growth retardants (PGRs). There was no delay in flowering of the first inflorescence from any PGR treatment, and a three to seven day delay in flowering of the second inflorescence with only Sumagic. Vegetative height was suppressed quadratically 14–28% (30 DAT) and linearly 19–40% (60 DAT) by increasing Cutless rates. Inflorescence heights of plants treated with 15 or 30 ppm Cutless were suppressed proportionally to foliage heights without any detrimental effect on floral display. Heights of plants treated with Cutless and transplanted into the landscape at 60 DAT were similar to those remaining in containers at 90 DAT, and 7 cm (3 in) and 11 cm (3.5 in) taller at 120 and 150 DAT, respectively. Vegetative heights of plants in both locations were suppressed linearly by Cutless, 15–33% (90 DAT) and 7–12% (120 DAT) with height suppression effects dissipating by 150 DAT. Vegetative height was suppressed quadratically by B-Nine/Cycocel, 5–14% and 16–28% at 30 and 60 DAT, respectively. However, response was inconsistent with rate at all sampling dates both in containers and in the landscape. B-Nine/Cycocel treated plants were suppressed quadratically up to 33% (90 DAT) and up to 17% (120 DAT). Plants transplanted and treated with B-Nine/Cycocel were suppressed linearly 14–23% (90 DAT) and 6–16% (120 DAT). At 150 DAT, BNine/Cycocel treated plants were similar in height to control plants, with transplanted plants around 10 cm (4 in) taller than those remaining in containers. Sumagic suppressed vegetative height quadratically 28–33% (30 DAT) and 50–52% (60 DAT). At 60 DAT, the height suppression was excessive and leaf orientation was altered to a less upright position. Inflorescence height suppression by Sumagic was considered excessive with first and second flower occurring below the surrounding foliage. Compared to those transplanted into the landscape at 60 DAT, plants treated with Sumagic and remaining in containers were 12% (90 DAT), 36% (120 DAT), and 37% (150 DAT) shorter. In both locations, Sumagic suppressed vegetative height quadratically 46% (90 DAT) and 29% (120 DAT) compared to control plants. Compared to control plants, at 150 DAT, treated plants remaining in containers were suppressed to a greater extent (32–43%) than those transplanted into the landscape (11–14%).

Growth response of Perovskia atriplicifolia (Russian sage) treated with several plant growth retardants (PGRs) was determined under three production regimes: 1) small plants in 10 cm (4 in) pots grown in a greenhouse and half transplanted into the landscape at 6 weeks after treatment (WAT), and 2) large plants grown in 3.8 liter (#1) pots in a greenhouse or 3) in an outdoor nursery. Plants in 3.8 liter (#1) pots were not transplanted into the landscape. Treatments included Cutless at 50, 100 and 150 ppm; Sumagic at 20, 40 and 60 ppm; B-Nine/Cycocel tank mixes at 2,500/1,500, 5,000/1,500 and 7,500/1,500 ppm; Pistill at 500 and 1,000 ppm; and a non-treated control. All PGRs controlled plant growth through 6 WAT in the greenhouse and 2 weeks after planting. At this time (8 WAT), plants treated with the most effective rate of Cutless (150 ppm), Sumagic (20, 40, or 60 ppm), B-Nine/Cycocel tank mixes (5,000 ppm/1,500 ppm), and Pistill (500 or 1,000 ppm) were 32%, 32%, 25%, and 32% smaller in 10 cm (4 in) pots and 21%, 22%, 22%, and 16% smaller in 3.8 liter (#1) pots, respectively, compared to non-treated controls. Treatment effects were non-significant by 4 weeks after plants grown in the greenhouse in 10 cm (4 in) pots for 6 weeks were transplanted into the landscape (10 WAT). Plants in 3.8 liter (#1) pots in the greenhouse were significantly smaller, excluding those treated with Pistill, than non-treated controls at 12 WAT; at this time, the most effective rate of Cutless (150 ppm), Sumagic (40 ppm), and B-Nine/Cycocel tank mixes (5,000 ppm/1,500 ppm) suppressed growth 21%, 23%, and 26%, respectively. For 3.8 liter (#1) pots in the nursery, Cutless suppressed growth 5–11% at 2 WAT only, and the most effective rate of Sumagic (60 ppm) reduced growth 7% at 4 WAT, but not thereafter. The most effective rates of B-Nine/Cycocel (7,500 ppm/1,500 ppm) and Pistill (1,000 ppm) suppressed growth 13% and 10%, respectively, at 8 WAT. Results suggest that PGR effectiveness is less outdoors under nursery conditions than in the greenhouse, particularly for Cutless and Sumagic. The duration and magnitude of B-Nine/Cycocel treatment effects suggest that this PGR combination may provide the most effective growth control of Russian sage under nursery conditions.

Salvia leucantha (Mexican sage) and Verbena canadensis ‘Homestead Purple’ were treated with the plant growth retardants (PGRs), Cutless, Sumagic, B-Nine/Cycocel tank mixes, or Pistill under both greenhouse and nursery conditions. Increasing rates of all PGRs applied to both species reduced plant size in the greenhouse for 6 weeks after treatment (WAT). Growth reduction of Mexican sage with the most effective rate (providing greatest growth control) of each PGR over this period averaged 11% with Cutless, 15% with Sumagic, 23% with B-Nine/Cycocel tank mixes, and 25% with Pistill. For verbena, size control with the most effective rate of each PGR averaged 15% with Cutless, 18% with Sumagic, 27% with B-Nine/Cycocel tank mixes, and 29% with Pistill. After transplanting greenhouse-grown plants into outdoor ground beds, only Mexican sage treated with B-Nine/Cycocel were significantly smaller 4 weeks after planting (WAP). Greenhouse-grown verbena treated with Sumagic, B-Nine/Cycocel tank mixes, and Pistill and planted in the landscape were 15—23%, 18–25%, and 0–20% smaller, respectively, than control plants at 2 WAP, but by 4 WAP, all PGR-treated verbena were similar in size to control plants. Under nursery conditions, Cutless and B-Nine/Cycocel tank mix reduced Mexican sage size up to 4 WAT. None of the PGRs affected plant size at 6 WAT. The most effective rate of each PGR (averaged over the duration that a PGR was significant) suppressed shoot growth 16% for Cutless, 12% with Sumagic, 20% for B-Nine/Cycocel tank mixes, and 29% for Pistill. For verbena only, Sumagic suppressed growth up to 10% at 2 WAT, and no PGR effectively controlled growth under nursery conditions 4 WAT.

A study conducted in 1998 and 1999 determined the effects of B-Nine (daminozide) at rates of 2500 to 7500 ppm, Pistill (ethephon) at rates of 125 to 1000 ppm, Bonzi (paclobutrazol) at rates of 33 to 99 ppm, and Cutless (flurprimidol) at rates of 50 to 150 ppm on vegetative growth and flowering of Canna x generalis ‘Florence Vaughan’ during nursery container production and landscape establishment. Vegetative height 30 and 60 days after treatment (DAT), vegetative and inflorescence heights at first flower, and vegetative height at 30 days after planting (DAP) in the landscape were reduced by Cutless in 1998 and 1999. Vegetative height was suppressed quadratically by increasing rates of Cutless, an average of 46% and 42% (1998) and 19.5% and 30% (1999) at 30 and 60 DAT, respectively. In 1998, Cutless delayed flowering one to six days, while in 1999 flowering was accelerated one to eleven days compared to untreated plants. At 30 DAP, height suppression from the lowest rate of Cutless was 5% in 1998 and 14% in 1999; however the effect was not significant at 60 DAP. With increasing rates of Bonzi, vegetative heights at 30 DAT and at first flower were suppressed 16% to 29% and 12% to 25% in 1998, respectively, but not at all in 1999. In 1998, inflorescence height at first flower decreased linearly to a maximum of 20% as Bonzi rate increased, with no effect in 1999. B-Nine did not affect vegetative or inflorescence height or flowering in 1998 or 1999, except for a three-to eight-day delay in flowering in 1998 and an one-to six-day acceleration in flowering in 1999. The only observed treatment effect of Pistill was a 9% to 17% linear height reduction at 30 DAT in 1999. B-Nine and Pistill did not exhibit effective, consistent height suppression in the 1998 or 1999 experiment and do not appear useful in controlling canna lily height.

In one experiment conducted in 1998 and two in 1999, Coreopsis rosea ‘American Dream’, or pink coreopsis, were treated with four plant growth retardants (PGRs): B-Nine from 2500 to 7,500 ppm, Cutless from 25 to 150 ppm, Sumagic from 10 to 40 ppm, and Bonzi from 25 to 100 ppm. The study was conducted to determine whether PGRs could be used to suppress growth of pink coreopsis without delaying flowering or causing phytotoxicity. Application of B-Nine, Cutless, or Sumagic suppressed plant growth 13–31% at first flower and when plants were marketable (one-third of flowers open) in all experiments and improved plant quality compared to controls. Plants treated with B-Nine, Cutless, or Sumagic had quality ratings 52–67% higher than those of control plants when marketable; treated plants appeared denser and more floriferous. Time to first flower and to a marketable stage were minimally affected by PGR application, and no phytotoxicity was observed. Bonzi did not significantly control growth or affect flowering of pink coreopsis in any of the three experiments.

An all ion-implanted monolithic broadband balanced mixer fabricated on a GaAs substrate for operation at W-band frequencies is described. A deep implanted buried n+ layer was used to minimize the diode series resistance. Ohmic contacts were formed by standard alloying of planar eutectic AuGe metallization into the n+ layer. The mixer diode structure is completely compatible with GaAs MESFET-based monolithic integrated circuit processing techniques. A conversion loss from 6.8 to 10 dB has been measured over an RF range of 75 to 88 GHz, with a LO drive of 10 dBm at 92 GHz.

In the summer of 1995 and 1996, 245 and 400 annual plant cultivars were evaluated for heat tolerance and landscape performance. Nine transplants of each cultivar were installed in raised beds amended with controlled-release fertilizer as per soil analysis recommendations, under full-sun and overhead irrigation, at the E.V. Smith Research Center in Shorter, Ala. (lat. 32° 30′ N, long. 85° 40′ W). No mainte-nance, with the exception of one midseason pruning of petunia, was performed on any of the cultivars. Catharanthus roseus 'Blush Cooler' was the best performer in 1995 with a mean rating of 4.1 (of 5.0). Salvia farinacea `Victoria Blue' and Petunia ×milliflora `Fantasy Pink' performed well, with a mean rating of 3.5. In 1996, the cultivar with the highest mean rating was Gomphrena globosa `Lavender Lady' (4.1). Second highest was G. globosa `Strawberry Fields' (4.0). Other cultivars that performed well in 1996 and had high mean ratings were Verbena × speciosa `Imagination' (3.6) and Melampodium paludosium `Derby' and `Medallion' (3.5 and 3.5).

Several monolithic integrated circuits have been developed to make a 30-GHz receiver. The receiver components include a low-noise amplifier, an IF amplifier, a mixer, and a phase shifter. The LNA has a 7-dB noise figure with over 17 dB of associated gain. The IF amplifier has a 13-dB gain with a 30-dB control range. The mixer has a conversion loss of 10.5 dB. The phase shifter has a 180° phase shift control and a minimum insertion loss of 1.6 dB.

This paper presents a chemical dynamic space power system which used storable propellants as fuels. The propellants currently being used are nitrogen tetroxide and a 50-50 blend of hydrazine and unsymmetrical dimethylhydrazine. The system prime mover is a reciprocating internal combustion engine which operates at approximately 4500 to 6000 rpm and delivers up to 4 1/2 hp with a nominal design power level of approximately 1 np. Development effort to date has indicated a promising space power capability of this concept. Analysis of the engine cycle, propellant 0/F ratio effects, and heat loss has provided a basis for system optimization and trade off studies. Application considerations of the major subsystems including the prime mover, lubrication, control and cooling for optimum performance is discussed.

This paper presents a chemical dynamic space power system which used storable propellants as fuels. The propellants currently being used are nitrogen tetroxide and a 50-50 blend of hydrazine and unsymmetrical dimethylhydrazine. The system prime mover is a reciprocating internal combustion engine which operates at approximately 4500 to 6000 rpm and delivers up to 4 1/2 hp with a nominal design power level of approximately 1 np. Development effort to date has indicated a promising space power capability of this concept. Analysis of the engine cycle, propellant 0/F ratio effects, and heat loss has provided a basis for system optimization and trade off studies. Application considerations of the major subsystems including the prime mover, lubrication, control and cooling for optimum performance is discussed.