SNA Research Conference Vol Floriculture. Joseph P. Albano Section Editor and Moderator. Floriculture Section 400

Transcription

1 Floriculture Joseph P. Alno Section Editor nd Modertor Floriculture Section 400

2 The Light Weight Aggregte HydRocks s Perlite Sustitute Jeremy M. Pickens, Jeff L. Siley, Glenn B. Fin, Chrles H. Gillim, nd John W. Olive Auurn University, Dept of Horticulture, Auurn, AL pickejm@uurn.edu Index of words: Prticle size, floriculture, porosity Significnce to the Industry: Perlite used in greenhouse production is expensive nd contins gret del of dust which is nuisnce nd potentilly hzrdous concern for workers. Lrge percentges of dust of fine ggregtes in perlite cn reduce the porosity expected form corse prticles. The results of this study suggest tht HydRocks lightweight cly ggregte could e used in plce of perlite to increse porosity without degrdtion in pet sed mixes. HydRocks is locl product of the southest nd is ville redily throughout the region. Nture of Work: Lightweight, pet-sed mixes re commonly mended with expnded perlite in order to increse porosity. Totl porosity influences wter retention nd ertion, oth of which re determined y the prticle size distriution nd pcking density t potting (2). In pet mixes, perlite is known to increse irspce nd decrese ville wter s the frction of perlite to pet increses (3). erlite s lightweight nture llows it to e ville redily in g or ulk shipments. Perlite, however, is expensive nd contins gret del of dust tht is nuisnce to workers nd hs rised helth concerns mong growers (personl communiction). The effectiveness of perlite s influence on porosity will depend upon the grde or qulity of the mteril used. The increse in dust nd smll prticles cn potentilly decrese porosity y filling in lredy ville pore spce. Dust nd fine ggregtes hve dul effect on sustrtes cost effectiveness nd physicl effectiveness. Physicl effectiveness is reduced, s mentioned, due to the reduced porosity from dust filling in the pore spce nd reducing the mount of corse (useful) ggregtes on volumetric sis. The cost effectiveness of the product is lso volumetric y replcing corse ggregtes in the g. Reduced utility nd expense contriute to need for perlite lterntive. HydRocks is light expnded cly ggregte mrketed for horticulture pplictions ville from Big River Industries (Alphrett, GA). HydRocks is formed y fully clcining cly t tempertures reching 2000 F in rotry kiln nd is redily ville from severl qurries in the southest. HydRocks is generlly inert nd ph neutrl when compred to most sustrte components. HydRocks hs ction exchnge cpcity (CEC) of 8 meq/100g. The ojective of the following experiments ws to evlute HydRocks s perlite sustitute in pet sed sustrtes. Mterils nd Methods: Six perlite (1 liter) smples were collected nd were ech sieved for 3 minutes using Ro-Tp (Ro-Tp RX-29; W.S. Tyler, Mentor, OH) sieve shker. Percentge of prticles retined on screens is reported on Tle 1. Floriculture Section 401

3 Aggregtes greter thn 2.36 mm (#8 U.S. Stndrd Sieves) were considered corse. Aztec Red Velvet nd New Guine Celerette Red (donted y Bll Horticulture, Chicgo IL) were used to evlute HydRocks effectiveness s perlite sustitute in hnging skets. Three plugs were potted seprtely into 8 hnging skets (8.0 ESL HB Dillen, Middlefield, OH ) filled with pet moss (Conrd Ffrd Inc. Agwm, MA) mended with the following mendment tretments: 15 % perlite, 15% course perlite ( 2.36mm ) 15 % course HydRocks, 7% reduced course perlite, nd 7% reduced course HydRocks (reduction sed on 45% of perlite smples eing 2.36; reduction equls 55% reduction in the mended percent (Tle 1)). Plnts were grown s suggested y Bll Horticulture Culture Sheets (1) for 13 weeks t the Ornmentl Horticulture Reserch Sttion, Moile, Alm in complete rndomized design nd hnd wtered s needed. Physicl properties of sustrte tretments were nlyzed using the NC Stte Porometers. Results nd Discussion: Perlite smpled contined 55% of wht ws considered medium nd fine ggregtes (< 2.36 mm) nd 45 % of wht ws considered corse ggregtes. Hnging skets were evluted on mrketility, root ll density, nd shoot fresh weight 13 weeks fter potting. No lock effect ws detected nd dt ws nlyzes s complete rndomized design using Duncn s Multiple Rnge Test. Mrketility ws sed on 5 point scle (1=not sellle, 5= high qulity). Imptient hnging skets hd no differences cross tretment in mrketility. Veren hnging skets mrketility ws highly dependent on tretment. Pet mended with 15% HydRocks hd the highest mrketility rting (4.6) nd ws similr to 7% HydRocks mendment (4.2). Pet mended with 7% corse perlite hd the lowest slility rting (1.6). Root density ws rted on 5 point scle with 5 hving the densest root system nd 1 eing the lest dense. Imptient hnging skets contining perlite were not different nd oth tretments contining HydRocks were not different. HydRocks tretments were different thn perlite tretments. HydRocks tretments hd lmost 3 times the density of perlite tretments. Veren skets hd similr results to the imptient skets in root density. Veren skets contining perlite were not different from ech other ut were different thn veren grown with HydRocks. Plnts grown in pet mended with 15% HydRocks hd the gretest density of roots cross tretments, with s gret s three times s mny roots s plnts s plnts in ny perlite tretment. Plnts in ech HydRocks tretment outperformed plnts grown in perlite tretments for oth species with regrds to mrketility, root density, nd shoot weight. Fresh weight ws tken for ech sket for oth species. Imptiens, cross tretments, were similr in shoot fresh weight. Veren hnging skets contining corse perlite tretments hd the lowest fresh weights for ll tretments. Pet mended with 15% perlite (61.5g) nd pet mended with 7% HydRocks (74.6g) were not different in fresh weight. Pet mended with 15% HydRocks hd the highest shoot weight cross tretments (101.6 g). Similr results were found with preliminry study (dt not shown) in which no plnt growth differences were seen etween perlite nd HydRocks. Shoot dry weights nd Floriculture Section 402

4 shoot qulity were not different etween perlite nd HydRocks ut immense differences were oserved in root density. HydRocks tretments outperformed perlite tretments y 3 fold in most situtions. The sitution in which these plnts were grown would e considered wet y most growers. No differences in mrketility were seen when oserving inptients ( wet tolerting plnt). However, veren (moisture sensitive) plnts were mrkedly different in mrketility nd overll qulity. No differences were found in porosity mong sustrtes using the NC Stte Porometer method (dt not shown), ut oservtions of the root systems indicted extreme differences in porosity. Perlite tretments hd no roots elow 3 of the continer surfce suggesting tht the continer styed to wet for dequte root growth. HydRocks grown plnts hd roots throughout the pot nd numer t the ottom of the root ll indicting tht moisture ws more prevlent t the ottom of the continer. Overll results cross ll oservtions suggest HydRocks s eing suitle perlite replcement in floriculture sustrtes. HydRocks ulk density (0.54 g/cm 3 ) is considerle higher thn tht of perlite (0.18 g/cm 3 ). The weight difference etween HydRocks nd perlite is more of concern in nursery continer production when crgo weight lod cpcity is plusile issue, however the crgo spce required for floriculture crops is greter thn nursery crops due to the deliccy of mterils. High spce requirements of floriculture crops dictte the lod insted of weight, therefore n increse in sustrte ulk density is not of gret concern with regrds to shipping. HydRocks is more uniform in size thn perlite nd it does not rek down over time or during hndling. HydRocks hs reltively low CEC (8 meq/100g) nd it is unlikely tht results were influenced y CEC, however further testing is wrrnted. It is currently unknown how HydRocks ggregtes ehve in different mechnicl mixing equipment nd cution should e tken when using HydRocks in mixers nd on conveyer elts. Literture Cited 1. Bll Bll Quick Culure. 18 Dec Bunt, A.C Medi nd Mixes for Continer Grown Plnts. Unwin Hymn, London, Englnd. 3. White, J.W. nd, J.W. Mstlerz Soil moisture s relted to continer cpcity. Proc. Am. Soc. Hort. Sci. 89: Floriculture Section 403

5 Tle 1. Anlysis of prticle size distriution of Perlite US stndrd Sieve opening Perlite sieve # (mm) Volume Z Weight Y 1/ / / Pn Z Men percent volume of perlite retined on ech screen from 1000 ml smple Y Men percent weight of mteril retined on ech screen from 100 g smple. Tle 2. Comprison of course HydRocks to perlite when mended in pet sed sustrte. Species Tretment Slility Z Root Density Y Fresh Weight Imptiens 85:15 (v:v) pet moss:perlite 4.8 A X 2.0 B A 85:15 (v:v) pet course:course perlite V 4.5 A 1.5 B AB 85:15 (v:v) pet moss:hydrocks 4.5 A 4.2 A AB 93:7 (v:v) pet moss:course perlite (reduced) U 4.5 A 1.5 B B 93:7 (v:v) pet moss:hydrocks (reduced) 4.8 A 4.2 A A Veren 85:15 (v:v) pet moss:perlite 3.4 BC 1.0 C 61.5 B 85:15 (v:v) pet course:course perlite 2.4 CD 1.0 C 36.2 C 85:15 (v:v) pet moss:hydrocks 4.6 A 4.2 A A 93:7 (v:v) pet moss:course perlite (reduced) 1.6 D 1.0 C 25.2 C 93:7 (v:v) pet moss:hydrocks (reduced) 4.2 AB 2.5 B 74.5 B Z Slility ws sed on scle on of 1 to 5 (1eing not slle; 5 eing high qulity). Y Root density ws sed on 5 point scle (1 eing poor with very few roots; 5 eing good full coverge). X Mens with different letters within columns re significntly different, seprted y Duncn's multiple rnge test (α = 0.05). W Perlite mm were considered course V Reduced mendments were sed on 55% of the perlite smpled eing < 2.36 mm; 7% is 55% reduction in 15% mendment rte. Floriculture Section 404

6 Slt Tolernce of Ten Bedding Plnts Genhu Niu nd Denise S. Rodriguez Texs AgriLife Reserch Center t El Pso, Texs A&M System 1380 A&M Circle, El Pso, TX gniu@g.tmu.edu Index Words: lndscpe irrigtion, slinity tolernce, wter reuse Significnce to Industry: Bedding plnts re extensively used in lndscpes in the United Sttes. As high qulity wter supply ecomes limited in mny prts of the world, recycled wter is eing encourged to irrigte lndscpes. Therefore, informtion on slt tolernce of edding plnts is of incresing importnce. This study quntified the reltive slt tolernce of ten edding plnts irrigted with wter t vrious slinity levels. The results indicted tht the selected edding plnts my e irrigted with wter t moderte slinity level without ny visul dmge, lthough growth my e reduced, depending on species. Nture of Work: Seeds of ten edding species (Tle 1) were sown on 20 Mrch 2008 in 72-cell trys filled with germintion mix (Sunshine Mix No. 5, SunGro Hort., Bellevue, WA). Seedlings were grown in 500-mL pots filled with similr potting mix with more nd corse perlite (Sunshine Mix No. 4, SunGro Hort.) in the greenhouse. On 23 My 2008, seedlings were trnsplnted to 2.6-L for the three ngeloni cultivrs, licorice plnt, nd plumgo or 10-L pots contining Sunshine Mix No. 4 for the other species. Slow relesed fertilizer 14N 6P 12K (Osmocote , Scotts-Sierr Hort. Products, Mrysville, OH) ws pplied t 5.0 g L -1 nd Micromx (Scotts-Sierr Hort. Products) t 0.5 g L -1. On 2 June 2008, ll plnts were moved to shde house with shde cloth of 25% light exclusion. Solutions of five slinity levels were prepred y dding pproprite mounts of sodium chloride (NCl), mgnesium sulfte (MgSO 4 7H 2 O), nd clcium chloride (CCl 2 ) t 87:8:5 (y weight) to tp wter, creting electricl conductivity (EC) of 1.5, 2.5, 3.5, 5.0, nd 7.0 ds m -1. The mjor ions in the tp wter were N +, C 2+, Mg 2+, Cl, nd SO 4 2 t 184, 52.0, 7.5, 223.6, nd mg L -1, respectively. The composition of the creted sline solutions ws similr to tht of the reclimed wter of locl wter utilities. A 100- L tnk of sline solution ws prepred ech time with confirmed EC for ech tretment. Sline wter irrigtion ws initited on 5 June nd terminted on 5 Sept Plnts were irrigted with 1 L or 2 L solutions per pot for 2.6 L or 10 L pots. Irrigtion intervls were determined ccording to plnt species, tretment nd wether conditions. Plnt height nd two perpendiculr cnopy widths were recorded monthly to clculte the growth index: (height + (width 1 + width 2)/2)/2. Upon termintion of the experiment, shoot dry weight (DW) ws determined fter oven-dried t 70 C to constnt weight. Dt were nlyzed seprtely y species. The experiment ws split-plot design with Floriculture Section 405

7 irrigtion wter s the min plot nd species s suplots with 6 replictions. To determine the threshold of slinity level, Student-Newmn-Keuls multiple comprison t P = 0.05 were conducted, in ddition to regression nlysis using SAS softwre (Version 9.1.3, SAS Institute Inc., Cry, NC). Results nd Discussion: All plnts survived, regrdless of tretment, except for ornmentl pepper Purple Flsh. The mortlity rte of Purple Flsh ws 17%, 17%, 33%, 50% nd 100%, respectively, when plnts were irrigted with solutions of 1.5, 2.5, 3.5, 5.0, nd 7.0 ds m -1. Since mortlity occurred t the eginning of the study, elevted slinity my not e the sole cuse. Further investigtion is needed on why Purple Flsh did not survive. No visul folir dmge ws oserved in ny species, regrdless of slinity tretment. Shoot DW of ngeloni White nd Lvender Pink decresed linerly s the EC of irrigtion wter incresed (Fig. 1). Shoot DW of ngeloni Purple decresed s EC incresed in qudrtic fshion. Generlly, there were no differences in shoot DW of ngeloni cultivrs t EC of 1.5, 2.5, nd 3.5 ds m -1. The EC of 5.0 nd 7.0 ds m -1 decresed shoot DW y 25% to 50% compred to those t EC of 2.5 ds m -1. Shoot DW of Blck Perl nd Clico decresed linerly s EC of irrigtion wter incresed nd the mgnitude of growth reduction ws lrger in Blck Perl thn in Clico. For exmple, per unit increse of EC, shoot DW decresed g nd 6.49 g in Blck Perl nd Clico, respectively. No differences in shoot DW of Purple Flsh were found. Among the three cultivrs of ornmentl peppers, Blck Perl ws the most sensitive to elevted slinity sed on its shoot DW reduction t every incresed level of EC of irrigtion wter. For vinc nd helenium, shoot DW lso decresed linerly s EC of irrigtion wter incresed. The shoot DW of licorice plnt t 7.0 ds m -1 ws lower thn those in other tretments nd shoot DW of plumgo t EC of 7.0 ds m -1 ws lower thn those t EC of 1.5 ds m -1 nd 2.5 ds m -1. Growth index of ngeloni White ws not ffected y the tretment (Fig. 2). For ngeloni Purple nd Lvender Pink, growth index ws generlly lrger t EC of 2.5 ds m -1 nd 3.5 ds m -1 compred to other tretments. In ornmentl peppers, growth index of Blck Perl decresed linerly s EC of irrigtion wter incresed, while those of Clico nd Purple Flsh were not ffected. Growth index of helenium nd vinc lso decresed linerly s EC incresed. No differences in growth index of licorice plnt nd plumgo were found mong the tretments. In summry, the threshold EC for minimizing growth reduction ws 3.5 ds m -1 for ngeloni nd ornmentl pepper Clico nd etween 3.5 to 5.0 ds m -1 for helenium, licorice plnt nd plumgo. Ornmentl pepper Blck Perl nd vinc tended to hve greter growth reduction s EC of irrigtion incresed. Although EC of recycled wter vry with loction nd wter source, EC of recycled wter is generlly elow 2 ds m -1. A wide rnge of slinity tolernce for herceous nnuls nd perennils hs een reported, nd some of them re sensitive slinity with folir injury (2, 3, 4). Since no folir injury ws oserved on ny species, these plnts my e considered moderte tolernt to slinity stress. Further confirmtion is needed for these edding plnts on Floriculture Section 406

8 their slinity tolernce ecuse the results of study were otined from single growing seson. Recommended slt tolernce or threshold of slinity for lndscpe plnts should e sed primrily on their estheticl ppernce, insted of mximizing growth (1), especilly for rpidly growing plnt species. For exmple, lthough significnt reduction of growth in ornmentl peppers Blck Perl nd Clico ws oserved under elevted slinity conditions, their compct ppernce my not hve significnt effect on their esthetic vlue, especilly when they re used s nnul ornmentl plnts. Literture Cited 1. Fox, L.J., J. N. Grose, B.L. Appleton, nd S.J. Donohue Evlution of treted effluent s n irrigtion source for lndscpe plnts. J. Environ. Hort. 23: Niu, G. nd D.S. Rodriguez Reltive slt tolernce of five herceous perennils. HortScience 41: Niu, G. nd D.S. Rodriguez Reltive slt tolernce of selected herceous perennils nd groundcovers. Scienti Hort. 110: Zollinger, N., R. Koenig, T. Cerny-Koenig, nd R. Kjelgren Reltive slinity tolernce of intermountin western United Sttes ntive herceous perennils. HortScience 42: Floriculture Section 407

9 Tle 1. A list of plnt species used in the experiment Botnicl nme Common nme Cultivr Angeloni ngustifoli Benth Angeloni Lvender Pink A. ngustifoli Benth Angeloni Purple A. ngustifoli Benth Angeloni White Cpsicum nnuum L. Ornmentl pepper Blck Perl C. nnuum L. Ornmentl pepper Clico C. nnuum L. Ornmentl pepper Purple Flsh Cthrnthus roseus (L.) G. Don Vinc Titn Helenium mrum (Rf.) H. Rock Helenium Dkot Gold Helichrysum petioltum (L.) DC. Licorice Plnt Silver Mist Plumgo uricult Lm. Plumgo Escpde Blue Seeds were provided y Bll Horticulturl Compny (Chicgo, IL). Floriculture Section 408

10 Shoot DW (g) Shoot DW (g) Shoot DW (g) Shoot DW (g) Angeloni 'Purple' Angeloni 'White' Angeloni 'Lvender Pink' DW= EC-0.38EC^2 (r 2 =0.94) Orn. pepper 'Blck Perl' Orn. pepper 'Clico' Orn. pepper 'Purple Flsh' c DW= EC (r 2 =0.95) DW= EC (r 2 =0.60) Helenium Licorice plnt DW= EC-0.86EC^2 (r 2 =0.98) d e DW= EC (r 2 =0.84) DW= EC (r 2 =0.99) DW= EC (r 2 =0.86) DW= EC (r 2 =0.98) Vinc Plumgo c c DW= EC (r 2 =0.70) NS EC of irrigtion wter (ds m -1 ) EC of irrigtion wter (ds m -1 ) EC of irrigtion wter (ds m -1 ) Fig. 1. Shoot dry weight (DW) of ngeloni (Angeloni ngustifoli) Purple, White, nd Lvender Pink, ornmentl pepper (Cpsicum nnuum) Blck Perl, Clico, nd Purple Flsh, helenium (Helenium mrum), vinc (Cthrnthus roseus), licorice plnt (Helichrysum petioltum), nd plumgo (Plumgo uricult) irrigted with wter t EC of 1.5, 2.5, 3.5, 5.0, or 7.0 ds m -1. Verticl rs represent stndrd errors. NS indictes nonsignificnce. Floriculture Section 409

11 40 Growth index (cm) Angeloni 'Purple' GI== EC-0.48EC^2 (r 2 =0.41) c c NS Angeloni 'White' GI= EC-0.49EC^2 (r 2 =0.61) Angeloni 'Lvender Pink' GI= EC (r 2 =0.21) Growth index (cm) Orn. pepper 'Blck Perl' Orn. pepper 'Clico' Orn. pepper 'Purple Flsh' c GI= EC (r 2 =0.79) c c NS NS Growth index (cm) GI= EC (r 2 =0.60) Helenium c c GI= EC (r 2 =0.85) c Vinc c EC of irrigtion wter (ds m -1 ) 0 50 Licorice plnt Plumgo Growth index (cm) NS GI= EC-0.41EC^2 (r 2 =0.96) NS EC of irrigtion wter (ds m -1 ) EC of irrigtion wter (ds m -1 ) Fig. 2. Growth index (GI) of ngeloni (Angeloni ngustifoli) Purple, White, nd Lvender Pink, ornmentl pepper (Cpsicum nnuum) Blck Perl, Clico, nd Purple Flsh, helenium (Helenium mrum), vinc (Cthrnthus roseus), licorice plnt (Helichrysum petioltum), nd plumgo (Plumgo uricult) irrigted with wter t EC of 1.5, 2.5, 3.5, 5.0, or 7.0 ds m -1. Verticl rs represent stndrd errors. NS indictes nonsignificnce. Floriculture Section 410

12 The Effect of Rootstocks on the Slinity Tolernce of Greenhouse Roses Alm R. Solís-Pérez nd Rúl I. Crer Deprtment of Horticulturl Sciences, Texs A&M University Coit Rod, Dlls, TX Index Words: slinity, irrigtion, wter qulity, dry weights, cut flower production Significnce to Industry: The production of greenhouse (cut flower) nd grden (lndscpe) roses is lrgely sed on cultivrs udded/grfted on rootstocks. Most rootstocks hve een historiclly selected to del with soil-orne diseses nd chllenging soil textures/structures, nd hve in generl enhnced the growth nd flowering performnce of the rose vrieties grfted on them. This study evluted the slinity tolernce of two widely used greenhouse rose rootstocks, Mnetti nd Ntl Brir. The results indicte tht Mnetti, used extensively in the US for over eight decdes, ws more tolernt to moderte NCl-CCl 2 slinities (0-24 mm rnge) thn the recently nd widely dopted Ntl Brir rootstock. As growers fce wter qulityrelted issues like use of nturlly sline irrigtion wters nd the need to recycle slty nd chemiclly-chllenging dringe effluents, the use of slt-tolernt rootstocks like Mnetti will ecome n importnt tool in the irrigtion-nutrition mngement of their rose crops. Nture of Work: The production of rose for oth cut flowers (greenhouse) nd grdens/lndscpes is lrgely sed on cultivrs udded/grfted on clonlly propgted rootstocks (8). The literture indictes tht rose growth nd flowering performnce is higher in grfted plnts thn in plnts growing on their own roots (5). Also, roses hve historiclly een reported to e sensitive to slinity, with significnt yield losses when the electricl conductivity (EC) in sturted soil/medi pste extrcts exceeds 3 ds/m nd/or sodium (N + ) nd chloride (Cl - ) concentrtions exceed 2-4 mm (1, 2, 6). Such EC levels re esily reched ecuse rose crops re typiclly irrigted with nutrient solutions (fertigtion) tht commonly rnge etween 1.5 nd 2 ds/m (2, 8). In recent yers, reduced vilility of good qulity irrigtion wter nd environmentl pressures re forcing growers to use poor qulity wters nd recycle/reuse leched nd run-off solutions, ll of which contriute to higher slt stress levels. Recent studies suggest tht greenhouse roses could tolerte incresing NCl-sed slinity levels (up to 30 mm), nd contend tht rootstock selection ws key fctor involved in this slt tolernce (3). Most slinity studies re sed on NCl, wheres the ion composition in irrigtion wters is often dominted long with- or y other ions like C 2+, Mg 2+, SO 4-2 nd HCO 3 - (4). The use of NCl s the min or only slinizing slt thus seriously limits the extent to which the results cn e interpreted nd extrpolted for prcticl ppliction (4). The min ojectives of this study were to evlute the Floriculture Section 411

13 interctive effects of slinity (mixed NCl-CCl 2 ) nd rootstock selection in greenhouse rose yield, qulity nd ion uptke responses. Rose plnts of the cv. Red Frnce grfted on the rootstocks R. Mnetti nd R. Ntl Brir, were trnsplnted into 20-L continers with pet: pine rk: snd sustrte (3:1:1 v/v) mended with 5 nd 1.3 l/yd 3 of dolomitic limestone nd Micromx micronutrient fertilizer, respectively. The pots were plced on grvel-lined eds within climte-controlled greenhouse (85 F dy/ 65 F night). A modified 0.5X Hoglnd No. 1 formultion (Hoglnd nd Arnon, 1950) ws used s the se (control) nutrient solution, which ws slinized with six NCl-CCl 2 (2:1 molr rtio) slt mixture concentrtions: 0, 1.5, 3, 6, 12 nd 24 mm. The plnts were irrigted sed on grvimetriclly-sed evpotrnspirtion mesurements nd enough solution ws pplied t ech irrigtion event to produce n verge leching frction of 25%. Crop mngement, flower hrvesting nd tissue smple collection over the 38-week experimentl period (there were six flushes of growth nd flowering) were done ccording to Lnghns (7). Dried nd ground lef tissue smples from flower shoots were nlyzed for essentil nutrient concentrtions, including N nd Cl. The experimentl design ws RCBD with fctoril (2 6) rrngement of rootstock (RS) y slt mixture concentrtions (SC), for totl of 12 tretments with 7 replictions (one plnt/continer s single repliction). Dt were nlyzed using SAS for Windows 9.1. Results nd Discussion: Leching frctions were similr etween rootstock selections nd mong slinity levels verging 25.1 ± 2.6%. There were no differences etween rootstocks for lechte EC nd Cl concentrtion [Cl], nd these two vriles were highly correlted (r=0.96, P<0.0001) nd positively ffected y incresing slt levels. The EC nd [Cl] throughout the experiment exceeded significntly the mximum thresholds recommended for roses (1, 2, 3, 6, 8), verging 3.0, 3.6, 6.4 nd 7.2 ds/m nd 177, 463, 1,473 nd 1,960 mg/l for the 0, 3, 12 nd 24 mm slt levels, respectively. Yield nd flower qulity: Totl verge flowering stem length, totl cumultive dry weight nd totl cumultive numer of flowering shoots hrvested per plnt (sum of ll hrvests) were ffected y the rootstock, with Mnetti plnts hving lrger vlues for ll vriles (Tle 1). Lef chlorophyll index (SPAD) ws the sme for oth rootstocks (Tle 1). Incresing concentrtions of the slt mixture in the nutrient solution hd detrimentl effect on totl cumultive dry weight, numer of flowering shoots hrvested per plnt, totl verge flower stem length, nd lef chlorophyll index (Tle 1; Fig. 1). Slt urn in folige. Since these rtings were sed on ctegoricl scle, they were nlyzed y Chi-squre test. The extent of slt injury on the lower folige of the plnts fter removing flowering shoots (older leves) ws different etween rootstock selections cross slt concentrtion levels (X 2 =35.2; P<0.0001). Folige of Mnetti plnts ws less ffected y slinity since pproximtely 83.3% of the plnts presented slt dmge on only 0-20% of the folige, 14.2% hd slt dmge on 21-60%, nd only 2.5% of the plnts hd slt dmge on % of the folige (Fig. 2). On the other hnd, in Ntl Brir 19% of the plnts hd dmge on 1-20% of the folige, 33.3% Floriculture Section 412

14 etween 21-40%, nd 47.7% hd slt urn dmge on % of the folige. Slt injury (s ronzing nd scorching of lef edges) on the lower leves of flowering shoots of oth rootstocks strted to pper y the hrvest event IV (144 DAT), in Mnetti plnts only for the highest SC (24 mm) while in Ntl Brir plnts slt dmge ws present on plnts exposed to the 3 to 24 mm SC (dt not shown). Tissue chloride concentrtion: There were interctions etween rootstocks (RS) nd DAT (P<0.0001), slt concentrtion levels (SC) nd DAT (P<0.0001), nd etween RS nd SC (P=0.0368). Lef [Cl] ws positively ffected y the slinity level (P<0.0001) similrly for oth rootstock selections (Fig. 3). Lef [Cl] incresed from one hrvest to the next in oth RS nd in ll SC (dt not shown), lthough their rte of chnge ws not the sme. Plnts on Mnetti hd higher lef [Cl] increse rtes over time for ll SC, except for the 24 mm. Across slt tretments lef [Cl] in Mnetti plnts verged 2.32, 4.28, 7.42, 7.62 nd 8.82 g/kg, t 31, 67, 144, 192 nd 265 DAT, respectively, with n verge increse of ~ 280% over the experimentl period. For Ntl Brir lef [Cl] vlues were 8.02, 9.25, 9.96, nd g/kg t 31, 67, 144, 192 nd 265 DAT, respectively, with n increse of ~53% over the experimentl period. Nevertheless, cross SC nd hrvest events, flower shoots of plnts grfted on Ntl Brir hd on verge 73% higher lef [Cl] thn those on Mnetti (overll verges of 5.9 vs g/kg, respectively). In oth rootstocks lef [Cl] hd negtive correltions with dry weight nd # of flower shoots hrvested per plnt (P< for oth RS nd vriles; r=-0.65 nd in Mnetti, respectively; nd, r=-0.36, nd in Ntl Brir, respectively). Tissue sodium concentrtion: For lef [N] there ws n interction mong RS, SC nd hrvest events (P=0.0103). Lef [N] In Mnetti plnts were similr etween hrvest events nd mong SC, verging 43.4 mg/kg. In Ntl Brir, on the other hnd, DAT nd SC hd interctive effects (P=0.0148), with verge lef [N] of 41 mg/kg for ll SC in hrvest II (67 DAT) incresing significntly ll the wy up to 70 mg/kg in the 24 mm SC level y hrvest V (192 DAT; dt not shown). No correltions etween lef [N] nd productivity nd qulity vriles were found in Mnetti plnts. The lef [N] in Ntl Brir plnts showed negtive correltions with dry weights nd numer nd length of flower stems, nd lef SPAD (P=0.0004, , , nd <0.0001; nd, r=-0.49, -0.45, -0.27,-0.54, respectively). Tissue clcium concentrtion: For lef [C] RS nd DAT hd interctive effects (P=0.0010). In Mnetti plnts lef [C] ws similr etween hrvests (vg g/kg), while in Ntl Brir they decresed y 17% from hrvest II to hrvest V (19.9 nd 16.6 g/kg). Slt stress hd liner positive effect on lef [C] (Fig. 3). In Ntl Brir plnts lef [C] ws correlted with stem length (P=0.0323; r=0.31) nd lef chlorophyll index (P=0.0277; r=-0.32), wheres no ssocitions were found etween C nd productivity/qulity vriles in Mnetti plnts. Conclusions: Across ll slinity tretments the rose plnts grfted on Mnetti were more vigorous, produced more nd longer flowering shoots per plnt, nd their folir slt urn injury ws considerly less compred plnts grfted on the Ntl Brir rootstock. These results confirm previous oservtions of Mnetti eing rootstock Floriculture Section 413

15 tht is reltively more tolernt to iotic stresses like wterlogging, slinity nd soil compction (2, 3, 5, 6, 8). These findings re significnt to the greenhouse rose industry, which hs widely dopted Ntl Brir s the primry rootstock due to its ese of propgtion grfting nd vigor under non-stressful greenhouse environments. As growers fce wter qulity-relted issues like use of nturlly sline irrigtion wters nd the need to recycle slty nd chemiclly-chllenging dringe effluents, the use of slt-tolernt rootstocks like Mnetti will ecome n importnt tool in the irrigtionnutrition mngement of their rose crops. Literture Cited 1. Bernstein, L., L.E. Frncois nd R.A. Clrk Slt tolernce of ornmentl shrus nd ground covers. J. Amer. Soc. Hort. Sci. 97: Crer, R.I Minerl nutrition. p In: A. Roerts, S. Gudin nd T. Deener (Eds.). Encyclopedi of Rose Science. Acdemic Press, London, UK. 3. Crer, R. I. nd P. Perdomo Ressessing the slinity tolernce of greenhouse roses under soiless production conditions. HortScience 38: Grttn, S.R. nd C.M. Grieve Slinity-minerl nutrient reltions in horticulturl crops. Sci. Hort. 78: Hnn, J. J. nd K.L. Grueer Understocks. p In: R.W. Lnghns (ed.). Roses. Roses Incorported. Hslett, MI. 6. Hughes, H. nd J. Hnn Effect of slinity in wter supplies on greenhouse rose production. J. Am. Soc. Hort. Sci. 103: Lnghns, R.W Building young plnts. p In: R.W. Lnghns (ed.). Roses. Roses Incorported. Hslett, MI (USA). 8. White, J.W Fertiliztion. p In: R.W. Lnghns (ed.). Roses. Roses Incorported. Hslett, MI (USA). Floriculture Section 414

16 Tle 1. Totl cumultive dry weight, numer of flowering shoots hrvested per plnt, verge stem length nd lef chlorophyll index in Red Frnce roses grfted on Mnetti nd Ntl Brir rootstocks, nd sujected to incresing NCl-CCl 2 slinity. The mens vlues per rootstock selection nd slt concentrtion level re verges of 42 nd 14 plnts, respectively. Min Effect Dry weight (g/plnt) Numer of Flowers Avg. Stem Length (cm) Chlorophyll Index (SPAD) Rootstock Mnetti Ntl Brir Difference Significnce z 22 ** 4 * 1.0 ** 0.0 ns NCl-CCl 2 (mm) EC (ds/m) z Significnce x L*** L*** L** Q* z Significnce ccording to GLM: ns, *, **, *** non significnt, nd significnt t P 0.05, P 0.01, P 0.001, respectively. y EC= estimted EC of pplied solutions (nutrient solution plus NCl-CCl 2 slts). Regression: L=liner, Q=qudrtic. x Floriculture Section 415

17 Figure 1. Totl verge flowering stem length (FSL) nd verge lef greenness (LCl), totl cumultive dry weight (TDW) nd numer of flower shoots hrvested (TFS) in Red Frnce roses sujected to incrementing NCl-CCl 2 slinity. Symols represent the men ± s.e. of 14 plnts. Significnce ccording to GLM: ns, *,**,*** non significnt, nd significnt t P 0.05, P 0.01, nd P 0.001, respectively. SC= slt concentrtion; EC= electricl conductivity. Figure 2. Slt dmge rtings in folige of Red Frnce roses grfted on Mnetti nd Ntl Brir rootstocks sujected to incresing NCl-CCl 2 slinity (n=42). Floriculture Section 416

18 Figure 3. Lef chloride (A), sodium (B) sodium nd clcium (C) concentrtions in flower shoots of Red Frnce roses grfted on Mnetti nd Ntl Brir rootstocks nd sujected to incresing NCl-CCl 2 slt stress. Symols represent the men ± s.e. of 7, 4 nd 8 plnts for plots A, B nd C, respectively. Symols oscure the error rs tht re not pprent. Significnce ccording to GLM: ns, *,**,*** non significnt, nd significnt t P 0.05, P 0.01, nd P 0.001, respectively. Floriculture Section 417

19 Horticulture s Therpy Christine Coker Mississippi Stte University Costl Reserch nd Extension Center 1815 Popps Ferry Rod, Biloxi, MS ccoker@r.msstte.edu Index Words: Horticulture, therpy, mentl helth Significnce to Industry: In time when mrketing is so importnt to the green industry, it is impertive tht the mny enefits of horticulture e recognized. Horticulture therpy is one venue in which the industry touches people s lives in qulittive mnner. It is well documented tht green spces, plnts, nd florl rrngements oost mood. Horticulture therpy tkes tht notion step frther y providing opportunity for people-plnt interction. Nture of Work: Horticulture hs trditionlly een defined s the production of specific, high-vlue plnts for the commercil mrket nd the susequent services relted to the instlltion nd mintennce of lndscpe plnts (2). The process of comining plnts nd people is t the core of horticulture therpy. As tretment used in psychitric settings horticulture therpy progrms strive to crete environments tht promote nd llow for growth (3). A therpeutic grden or nture-sed setting provides stress-reducing, mood-enhncing qulities setting the stge for soothing therpeutic interction, while group or individul work in the setting cn foster ehviorl nd socil lerning to help reduce mldptive ehvior (1) The Mentl Helth Assocition of Mississippi ws estlished in 1963 s grssroots orgniztion to serve the mentl helth needs of the citizens of Hrrison County, MS. As n dvoccy gency giving voice to the mentl helth needs of the community, the Assocition now serves clientele in 3 costl counties. One of the Assocition s services is the Opl Smith Dy Support Center which provides recretionl, socil, nd work skills trining opportunities for persons with mentl illness or experiencing homelessness. Discussion: Wht egn s one-time invittion to help the Center s clientele plnt flowers in continers hs grown to ecome qurterly progrmming opportunity. Progrms now include continer grdening, vegetle identifiction, preprtion, nd nutrition, s well s food hygiene. With this incresed prticiption comes severl opportunities for outrech nd study. The gol of this work is not only to educte those citizens with mentl helth concerns, ut lso to promote cognitive, physicl, psychologicl, nd socil functioning through the use of horticulture. Floriculture Section 418

20 Feedck from prticipnts hs een overwhelmingly positive. In some instnces, the clients hve never even plnted seed efore. The experience of nurturing living thing throughout the seson instills sense of wonder nd pride in the ptients. Throughout the exercises, clients re encourged to sk questions nd prticipte in discussion. Often questions rise out the prticulrs of the plnts nd the hndling of the mteril. On mny occsions, clients simply shre their own grdening experiences with the group. While the sessions re optionl for the clients, most present prticipte. Severl people choose to oserve without ctully tking prt in the ctivity. Those clients usully contriute to the discussion or choose to prticipte in the next session. While the field of horticulture therpy is rpidly growing, there is still gret need for pplied reserch. Such reserch will ensure tht horticulture therpy ecomes universlly nd unequivoclly recognized therpy option for the mentlly ill (4). The field of horticulture therpy is lso one more identifile component of the enefits tht the green industry provides the pulic. Literture Cited 1. DeBevois, K Green thum therpy: plnting the seeds of utonomy through horticulture therpy. Therpy Times 17 Apr (Accessed 17 Dec 2008). 2. Relf, P.D Humn issues in horticulture. HortTechnology 2(2): Shpiro, B.A. nd M.J. Kpln Mentl illness nd horticulturl therpy prctice. In: S.P. Simson nd M.C. Strus (Eds.) Horticulture s Therpy: principles nd prctices. New York, Food Products Press. pp Willims. P.N. nd P.M. Willims Applied reserch for horticulturl therpy prctice. In: S.P. Simson nd M.C. Strus (Eds.) Horticulture s Therpy: principles nd prctices. New York, Food Products Press. pp Floriculture Section 419

21 Effects of Wter Stress nd Plnt Growth Regultors on Flowering nd Growth of Bouginville Rsperry Ice Shen M, Mengmeng Gu, Brin W. Trder Deprtment of Plnt nd Soil Sciences, Mississippi Stte University, MS Index words: Chlormequt chloride, dminozide, ethephone Significnce to Industry: Bouginville is very populr tropicl nd sutropicl evergreen lndscpe plnt with showy, virntly colorful petloid rcts. However, the vigorous grow hit mkes ouginville lor intensive plnt s continer plnt. It is necessry to do regulr pruning ecuse the shoots often grow too vigorously. The ojective of this study ws to investigte the fesiility of plnt growth regultors (PGR) nd wter stress s lterntives to prune ouginville s potted plnts. Nture of Work: Experiment ws conducted in Mississippi Stte University greenhouse. One rooted cutting of Rsperry Ice ouginville ws trnsplnted in 6 pot with Sunshine Mix #1 (SunGro Hort., Bellevue, WA) on 16 Jn Plnts were fertilized with 200 ppm 20N 4P 16K (Peters , Scotts Professionl, Allentown, PA). All plnts were pruned to pproximtely 6 on 9 My. This experiment ws strted on 13 My nd finished on 8 Aug Plnts treted with chlormequt chloride (Cycocel, OHP, Inc., Minlnd, PA) nd ethephone (Florel, Southern Agriculturl Insecticides, Inc., Boone, NC) were folir spryed with 0.43 ounces PGR solution with surfctnt (Spreder sticker, Voluntry Purchsing Group, Inc., Bonhm, TX) with trigger spryer. Plnts treted with dminozide (Dzide TM, Fine Americs Inc., Wlnut Creek, CA) nd tretments with dminozide were drenched y pplying 3.4 ounce PGR solution per pot. Sustrtes in pot were kept reltive dry efore drenching to minimize leching from the pot. PGRs tretments were conducted on 13 My nd 26 My. Wter stress ws withholding wter from 13 My to 24 My until mild wilt occurred. Supplementry wtering strted on 24 My y giving 50ml fertilizer solution per pot every other dy for 3 weeks. Dminozide nd chlormequt chloride were tnk mixed nd were pplied y drench to the medi, nd the pplictions were conducted on 6 June nd 20 June. Experiment ws in completely rndomized experimentl design with eight replictions per tretment. During the experiment, nturl dylength ecme longer from 13 My t 13.8 h to 22 June t 14.3 h, nd then declined to 13.5 h on 8 Aug The temperture in the greenhouse ws set up s 35 C/25 C (dy/night). The numer of structurl rnches (rnch>1 inch long) per plnt were counted efore nd 4 weeks fter the experiment strted. The numer of inflorescences (rcteole >0.8 Floriculture Section 420

22 inch) for ech plnt ws counted every week. Plnt height ws recorded every other week. Results nd Discussion: Of ll tretments pplied in the experiment (Tle 1), 1,000 ppm nd 1,500 ppm ethephone nd the comintion of wter stress nd 1,000 ppm ethephone hd significnt lower increse in height compred to control. Although not sttisticlly significnt, seven other tretments tht induced 40% less increse in height thn control included 1,800 ppm chlormequt chloride, wter stress ppm chlormequt chloride, wter stress + 1,250 ppm dminozide, wter stress ppm dminozide + 1,000 ppm chlormequt chloride, 500 ppm ethephone, wter stress ppm ethephone, nd wter stress + 1,500 ppm ethephone. Wter stress, 600 ppm chlormequt chloride, wter stress + 2,500 ppm dminozide + 2,500 ppm chlormequt chloride significntly induced more inflorescences thn control. Although not sttisticlly significnt, six other tretments tht induced pproximtely 3 inflorescences more thn control included wter stress ppm chlormequt chloride, wter stress + 1,200 ppm chlormequt chloride, wter stress + 1,800 ppm chlormequt chloride, wter stress + 2,500 ppm dminozide, wter stress ppm dminozide + 1,000 ppm chlormequt chloride, nd wter stress + 1,250 ppm dminozide + 1,250 ppm chlormequt chloride. Tretments including 1,000 ppm nd 1,500 ppm ethephone produced significntly less rnches compred to control. Although not significntly, ll the other tretments except 1,250 ppm dminozide produced less rnches thn control 4 weeks fter experiment strted. Although ethephone ws very effective in controlling growth in height in ouginville t two high concentrtions pplied in the experiment, significnt defolition ws oserved with ppliction of ethephone (Figure 1). There ws liner reltionship etween ethephone concentrtion nd percentge of defolition with two high concentrtions of ethephone induced close to 100% or 100% defolition in ouginville. When eing used for controlling growth in ouginville, ethephone should not e pplied t high concentrtion (>1,000ppm) due to possiility of reduced esthetic vlue from defolition. Previous reserches indicted tht dikegulc (Atrimmec, Gordon s, Knss City, MI) did reduce the height of Rsperry Ice nd Sn Diego Red ouginville under short dys without enhncing flowering (Dierking nd Snderson, 1985). While 1600 mg dikegulc/liter ws reported stimulted profuse flowering on Brr Krst nd Rinow Gold ouginville during midspring to erly summer (Norcini et l., 1993). 1 ounce/gllon of dikegulc ws recommended to induce rnching. Besides, enzyldenine t ppm ws reported to induce lterl rnching s well s retrd growth. chlormequt chloride, ncymidol (A-Rest TM, SePRO, Crmel, IN), nd pcloutrzol (Bonzi, Syngent Crop Protection, Inc., Greensoro, NC) were reported effective to retrd ouginville growth (Koyshi et l., 2007; Sho et l., 2006; Tng et l., 2006). Bsed on the results in this experiment, three-week wter stress nd wter stress + 2,500 ppm dminozide + 2,500 ppm chlormequt chloride cn e conducted to promote Floriculture Section 421

23 flowering nd my hve slight effect on producing compct plnts. Chlormequt chloride t low concentrtion could promote flowering in ouginville while higher concentrtions produced more compct ouginville plnts in the experiment. Dminozide lone did not show significnt effect on ouginville flowering or controlling growth in this experiment. Ethephone lone or comined with wter stress could control height in ouginville, however defolition induced t high concentrtion might not e ppeling to growers due to reduced esthetic vlue of plnts. Literture Cited: Cuevs, J., M.L. Cnete, V. Pinillos, A. J. Zpt, M. D. Fernndez, M. Gonzlez, nd J. J. Hueso Optiml dtes for regulted deficit irrigtion in Algerie loqut (Eriootry jponic Lindl.) cultivted in Southest Spin. Agriculturl Wter Mngement 89: Dierking, C.M. nd K.C. Snderson Effect of vrious chemicl spry tretments on Bouginville spectilis Wild. Proc. Southern Nurserymen s Assn. Res. Conf.30: Koyshi, K.D., J. McConnel, nd J. Griggis University of Hwii t Mno Ornmentl nd Flowers, Coopertive Extention Service OF-38. Norcini, J.G., J.M. McDowell, nd J.H. Aldrich Dikegulr improves ouginville flowering during two production sesons. HortScience 28: Sho, Z., Y. Yng, S. Qiu The study of dvnce of flowering time regultor of Bouginville glr. Chinese Agriculturl Science Bul. 22: Tng, Y., J. Zhu, Y. Hung, nd Z. Liu Flower period control techniques on Bouginville spp. Journl of West Chin Forestry Science 35: Floriculture Section 422

24 Tle 1. Effects of wter stress nd plnt growth regultors pplied on growth nd flowering of Rsperry Ice ouginville trnsplnted on 16 Jn Tretment (ppm) Increse in height z (cm) No. of inflorescences/ plnt y Increse No. of rnches x /plnt Control 5.8 w 0.4d 3.6 Three-week wter stress 3.6cde c CCC v (600) c 2.5c CCC (1,200) 4.6c 1.1cd 3.3 CCC (1,800) 2.6cde 1.8cd 1.9c Wter stress + CCC (600) 2.9cde 4.1cd 2.0c Wter stress + CCC (1,200) 4.9c 3.0cd 2.4c Wter stress + CCC (1,800) 3.6cde 3.4cd 2.5c Dzide u (1,250) 5.0c 0.1d 3.4 Dzide (2,500) 4.9c 2.0cd 3.0 Dzide (3,750) 3.6cde 0.7cd 3.0 Wter stress + Dzide (1,250) 3.4cde 1.8cd 2.9 Wter stress + Dzide (2,500) cd 2.4c Wter stress +Dzide (3,750) 4.8c 0.5cd 2.9 Wter stress +Dzide (800) + CCC (1,000) 3.5cde 3.3cd 1.1cd Wter stress +Dzide(1,250) + CCC (1,250) 4.8c 3.5cd 1.1cd Wter stress +Dzide(2,500) + CCC (2,500) 4.0cd c Ethephone (500) 3.4cde 0.0d 2.1c Ethephone (1,000) 0.8de 0.0d 1.9c Ethephone (1,500) 0.4e 1.0cd 0.7cd Wter stress + Ethephone (500) 2.9cde 0.9cd 2.3c Wter stress + Ethephone (1,000) 1.6cde 0.0d 0.0d Wter stress + Ethephone (1,500) 2.8cde 0.0d 0.0d z Increse in height ws recorded on 8 Aug y Numer of inflorescences (rcteole>0.8 inch) ws recorded on 17 July x Increse numer of rnches dt were only recorded on rnch>1 inch on 11 June2008. w Mens followed y sme letters re not significntly different y LSD multiple comprison (P=0.05). v Chlormequt chloride u Dminozide Floriculture Section 423

25 Figure 1. The correltion etween folir spry concentrtion of ethephone nd visul rting of defolition for Rsperry Ice ouginville on 18 My 2008 Floriculture Section 424

26 Effects of Plstic Mulch Color on Cut Flower Size in Snpdrgons Grown in High Tunnel Willim G. Sherrer, J. Rymond Kessler, Jr., Wheeler G. Foshee, nd Jmes E. Brown Auurn University, Deprtment of Horticulture, Auurn, AL Index words: Antirrhinum mjus, cut flowers, high tunnels, colored plstic mulch Nture of work: High tunnels re simplified growing systems tht enhnce crop growth, yield, nd qulity (Wells, 1998). They re nonpermnent, infield structures, lcking electricl service, utomted ventiltion, nd permnent heting systems, though temporry heters my e used during frosts, tht resemle trditionl polyethylene covered greenhouses, ut re completely different technology (White et l., 2003; Wells, 1998). High tunnels re used for growing seson extension in the spring nd fll. They produce excellent flower qulity nd mke it possile to hrvest cut flowers erlier in the spring nd lter in the fll thn in n open ir, field environment. High tunnels enefit cut flower production y offering mny production options rnging from herceous perennils, eing over-wintered for spring cut flower production, to summer nnuls, nd nturl fll seson mums (Lmont et l., 2003). Most cut flowers sold in the U.S. re imported from Columi nd the Netherlnds (USDA APHIS, 1996). Despite the high volume of cut flower imports, the U.S. mrket hs demnd for domesticlly grown cut flowers. Loclly grown cut flowers cn e delivered fresh to the florist eliminting prolems ssocited with shipping nd the extr cost. Snpdrgons (Antirrhinum mjus) must e stored nd shipped upright ecuse the stems end upwrds if they re not (Armitge nd Lushmn, 2003). This nd their need to e refrigerted cn cuse prolems with importtion into the U.S. The wrm tempertures tht snpdrgons cn e exposed to t irport loding docks cn gretly decrese their usle florl life. Seedlings from plug flts of Potomc Apple Blossom, Yellow, Ornge, nd Pink nd Supreme Gold Yellow snpdrgons (Antirrhinum mjus) were plnted 18 seedlings per plot, 3 plnts cross row with the rows spced 6 inches (15.24cm) prt nd 6 per row with 4 inches (10.16cm) etween seedlings in the row on July 30 th, 2007 in 2.5 foot (0.762m) wide rised eds covered with red, white, or lue plstic mulch in high tunnel (21ft (6.4m) wide x 48ft (14.63m) long x 10.5ft (3.2m) high) t E.V. Smith Reserch Center in Shorter, AL. They were irrigted with T-Tpe (0.45 gpm/100ft) (T- Systems Interntionl, Sn Diego, CA) nd fertigted using Dostron (Dostron, Clerwter, FL) injector t 150ppm N using Jck s Professionl Wter-Solule Fertilizer (J.R. Peters, Inc., Allentown, PA) every wtering. Once the snpdrgons were tll enough to need support, 4ft (1.22m) Fi-Shock (Woodstrem Corportion, Lititz, PA) Step-In Fence Posts set on either side of the ed to hold 2 ft (0.61m) wide MxiGrid Wrning Brrier Fencing (Esy Grdener Products, Inc., Wco, TX) over the eds nd prllel to the ground to support the snpdrgons. The support ws moved up s the snpdrgons grew tller. The snpdrgons were hrvested whenever 75% of plot Floriculture Section 425

27 hd open flowers. Hrvests occurred on Septemer 24 th nd 29 th nd Octoer 2 nd nd 8 th, Inflorescence length, stem length, nd stem dimeter 12in from the se were mesured for ech plnt. The dt were nlyzed using completely rndomized split plot design with mulch color s the min plot, cultivr s the su-plot, nd three replictions of ech mulch tretment. Results nd Discussion: Blue mulch produced the longest stems nd red mulch produced the shortest stems for ll snpdrgon cultivrs except Supreme Gold Yellow. Of the cultivrs tht responded, stem length of plnts on lue mulch were 3.5% to 10.6% longer thn on red mulch. Supreme Gold Yellow nd Potomc Ornge produced the longest stems of the cultivrs in ll of the mulch tretments. White nd lue mulch produced the lrgest stem dimeters of the mulch tretments. Potomc Yellow hd the lrgest nd Potomc Apple Blossom nd Supreme Gold Yellow hd the smllest dimeters of the cultivrs. The white nd lue mulch produced the longest inflorescences of the mulch tretments nd the red mulch produced the shortest inflorescences, ut red ws not different from lue mulch. As with stem length, Supreme Gold Yellow nd Potomc Ornge inflorescence lengths were longer thn other cultivrs. Bsed on the results of this study, lue mulch is the est choice for summer-fll production of snpdrgons in high tunnel ecuse it yielded the longest stem lengths, which is n importnt criterion for cut flower qulity. In mny cses, white mulch performed s well s lue mulch, ut red mulch performed poorly. Literture Cited Armitge, A.M. nd J.M. Lushmn Specilty Cut Flowers Second Edition. Timer Press, Portlnd, OR. Lmont, W.J., M.D. Orzolek, E.J. Holcom, K. Demchk, E. Burkhrt, L. White, nd B. Dye Production System for Horticulturl Crops Grown in the Penn Stte High Tunnel. HortTechnology 13(2) pp USDA Animl nd Plnt Helth Inspection Service Importing cut flowers. June (Lst ccessed Octoer 2007) Wells, O.S Rowcovers nd High Tunnels Growth-enhncing Technology. Vegetle Production Using Plsticulture. A.S.H.S. Press, Alexndri, VA. pp White, L., E. Burkhrt, W. J. Lmont, nd M. D. Orzolek High Tunnel Production Mnul. The Pennsylvni Stte University College of Agriculture Deprtment of Horticulture Center for Plsticulture. Floriculture Section 426