The Effect of Cultural Practices on Growth, Flowering and Rooting of Adenium obseum

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Title:
The Effect of Cultural Practices on Growth, Flowering and Rooting of Adenium obseum
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1 online resource (116 p.)
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english
Creator:
Mcbride, Kaitlyn M
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University of Florida
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Gainesville, Fla.
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Thesis/Dissertation Information

Degree:
Master's ( M.S.)
Degree Grantor:
University of Florida
Degree Disciplines:
Horticultural Science, Environmental Horticulture
Committee Chair:
Henny, Richard J
Committee Co-Chair:
Chen, Jianjun
Committee Members:
Norman, David J
Guy, Charles L

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Subjects / Keywords:
adenium -- fertilizer -- growth -- light -- propagation
Environmental Horticulture -- Dissertations, Academic -- UF
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Horticultural Science thesis, M.S.
bibliography   ( marcgt )
theses   ( marcgt )
government publication (state, provincial, terriorial, dependent)   ( marcgt )
born-digital   ( sobekcm )
Electronic Thesis or Dissertation

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Abstract:
Light and nutritional levels affected growth, flowering and visual quality of containerized Adenium obesum ‘Ice Pink’ and ‘Red’. Plants were grown in full sun, 30% or 50% shade in 1.25 L pots and top-dressed with slow release fertilizer at 2, 4 or 6 grams of fertilizer per liter of soil volume. After 16 weeks, both cultivars produced the best growth, flowering and quality when fertilized with 6 grams/L rate under 30% shade. A second experiment with cultivar Red confirmed the previous results. Greenhouse studies with ‘Red’ grown in 1.25 L and 3.0 L pots with four fertilizer rates (2, 4, 6, or 8 grams/L) showed the largest, most floriferous and best quality plants after 20 weeks when fertilizer rate was 6 or 8 grams/L for plants in both 1.25 L and 3.0 L pots. Plants in 3.0 L pots produced significantly higher top and root dry weights than those in 1.25 L pots. Propagation tests using Adenium obesum ‘Ice Pink’ and ‘Red’ vegetative tip cuttings showed best rooting occurred in cuttings treated with 8000 mg/L IBA or a combination of 8000 mg/L IBA plus 4000 mg/L NAA.
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In the series University of Florida Digital Collections.
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Includes vita.
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by Kaitlyn M Mcbride.
Thesis:
Thesis (M.S.)--University of Florida, 2012.
Local:
Adviser: Henny, Richard J.
Local:
Co-adviser: Chen, Jianjun.
Electronic Access:
RESTRICTED TO UF STUDENTS, STAFF, FACULTY, AND ON-CAMPUS USE UNTIL 2014-08-31

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UFE0044697:00001


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1 THE EFFECT OF CULTURAL PRACTICES ON GROWTH, FLOWERING, AND ROOTING OF ADENIUM OBESUM By KAITLYN M ARIE MCBRIDE A THESIS PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIREMENT S FOR THE DEGREE OF MASTER OF SCIENCE UNIVERSITY OF FLORIDA 2012

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2 2012 Kaitlyn M arie McBride

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3 To Dr. Henny, Mrs. Henny, and Terri Mellich. Thank you all so much, for everything, I would not be here if not for you.

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4 ACKNOWLEDGMENTS I would like to thank Dr. Henny, Terri Mellich, Dr. Chen, Dr, G uy, Dr. Norman, and Mrs. Henny for all of their help during the whole process. Ogle sby Plants International thank you for the generous donation of plant material. Finally, I would like to thank Jesse and my parents for all of thei r love and support.

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5 TABLE OF CONTENTS page ACKNOWLEDGMENTS ................................ ................................ ................................ .. 4 LIST OF TABLES ................................ ................................ ................................ ............ 7 LIST OF FIGURES ................................ ................................ ................................ .......... 9 LIST OF ABBREVIATIONS ................................ ................................ ........................... 11 ABSTRACT ................................ ................................ ................................ ................... 13 CHAPTER 1 INTRODUCTION ................................ ................................ ................................ .... 14 2 EFFECTS OF NUTRITION AND LIGHT LEVELS ON GROWTH AND FLOWERING OF ADENIUM OBESUM .............................. 23 Materials and Methods Experiment 1 1 ................................ ................................ .. 23 Results and Discussion Experiment 1 1 ................................ ................................ 24 ................................ ................................ ................................ ........... 24 ................................ ................................ ................................ ................. 25 Data Experiment 1 1 ................................ ................................ ............................... 26 Materials and Methods Experiment 1 2 ................................ ................................ .. 37 Results and Discussion Experiment 1 2 ................................ ................................ 38 Data Experiment 1 2 ................................ ................................ ............................... 41 Material s and Methods Experiment 1 3 ................................ ................................ .. 48 Results Experiment 1 3 ................................ ................................ ........................... 50 Soluble Salts and pH ................................ ................................ ........................ 52 Mineral Nutrient Analysis Results ................................ ................................ ..... 52 Data Experiment 1 3 ................................ ................................ ............................... 56 3 PROPAGATION OF ADENIUM OBESUM VEGETATIVE TIP CUTTINGS ................................ ................................ ............... 69 Introduction ................................ ................................ ................................ ............. 69 Materials and Methods ................................ ................................ ............................ 72 Experiment 1 ................................ ................................ ................................ .......... 74 Experiment 2. ................................ ................................ ................................ .......... 74 Experiment 3. ................................ ................................ ................................ .......... 75 Experiment 4. ................................ ................................ ................................ .......... 76 Experiment 5. ................................ ................................ ................................ .......... 76 Experiment 6. ................................ ................................ ................................ .......... 77 Experimen t 7. ................................ ................................ ................................ .......... 77 Experiment 8. ................................ ................................ ................................ .......... 78

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6 Experiment 9. ................................ ................................ ................................ .......... 79 Experiment 10. ................................ ................................ ................................ ........ 79 Experiment 11. ................................ ................................ ................................ ........ 80 Discussion ................................ ................................ ................................ .............. 81 4 CONCLUSION ................................ ................................ ................................ ........ 93 APPENDIX: EXTRA DATA TABLES AND FIGURES ................................ .................... 96 LIST OF REFERENCES ................................ ................................ ............................. 113 BIOGRAPHICAL SKETC H ................................ ................................ .......................... 116

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7 LIST OF TABLES Table page 1 1 Adenium obesum quality. ................................ ................................ ................................ ................ 26 1 2 Effect of shade and fertilizer level on growth of Adenium obesum ..... 27 1 3 Adenium obesum and visual quality. ...... 30 1 4 Effect of shade and fertilizer level on growth of Adenium obesum ........... 31 1 5 Effect of three shade and fertilizer levels on Adenium obesum ................ 41 1 6 Effect of shade and fertilizer level on Adenium obesum ............................ 42 1 7 Effect of four fertilizer levels on Adenium obesum ................................ ..... 56 1 8 Effect of four fertilizer levels on Adenium obesum ................................ .... 57 1 9 Effects of four fertilizer rates on the soluble salt concentration and pH balance of Adenium obesum ................................ ................................ .............. 62 1 10 Effect of four fertilizer levels on ele mental values of Adenium obesum flowers ................................ ................................ ................................ ................ 63 1 11 Effect of four fertilizer levels on elemental values of Adenium obesum leaves ................................ ................................ ................................ ................ 64 1 12 Effect of four fertilizer levels on elemental values of Adenium obesum stems. ................................ ................................ ................................ ................. 65 1 13 Effect of four fertilizer levels on elemental values of Aden ium obesum roots. ................................ ................................ ................................ .................. 66 2 1 A list of rooting compounds and the active ingredients used for cutting propagation experiments with Adenium obesum ................ 84 2 2 Effects of four rooting compounds on Adenium obesum ............. 84 2 3 Effects of four rooting compounds on Adenium obe sum ....... 84 2 4 Effects of four rooting hormones on Adenium obesum .......... 85 2 5 Effe cts of four rooting hormones on Adenium obesum ......... 85 2 6 Effects of four rooting compounds on Adenium obesum ........ 85

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8 2 7 Effects of f our rooting compound on Adenium. obesum ....... 86 2 8 Effects of four rooting compounds on Adenium. obesum ...... 86 2 9 Effects of four ro oting hormones on Adenium obesum .. 86 2 10 Effects of four r ooting compounds on Adenium obesum ............. 87 2 11 Effects of four rooting compounds on Adenium obesum .................... 87 2 12 Ef fects of four rates of IBA +NAA on Adenium obesum ........................... 87

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9 LIST OF FIGURE S Figure page 1 1 Interaction of three fertilizer levels and three light levels on Adenium obesum ................................ ................................ ................................ ............ 28 1 2 Interaction of three fertilizer levels and three light levels on Adenium obesum ................................ ................................ ................................ ............ 29 1 3 Interaction of three fertilizer and light levels on Adenium obesum ............. 32 1 4 Interaction of three fertilizer levels and three light levels on Adenium obesum ................................ ................................ ................................ ................... 33 1 5 Adenium obesum t) of growth .............. 34 1 6 Adenium obesum .............. 34 1 7 Adenium obesum th. ............. 35 1 8 Adenium obesum ................... 35 1 9 Adenium obesum August ) of growth .................... 36 1 10 Adenium obesum to August) .................... 36 1 11 Light levels of 0%, 30% or 50 % shade from July to December 2011. ................ 43 1 12 The effects of increasing fertilizer rates on average weekly flower number of Adenium obesum ................................ ................................ ...................... 43 1 13 The effects of increasing fertilizer rates on the average weekly flower number of Adenium obesum ................................ ................................ .................. 44 1 14 The effects of increasing fertilizer rate on the average w eekly flower number of Adenium obesum ................................ ................................ .................. 45 1 15 Experimental Design was 3 shade levels and 3 fertilizer levels with 6 replications of Adenium obesum ................................ .............................. 45 1 16 Adenium obesum ........ 46 1 17 Adenium obesum shade ................................ ................................ ................................ .................. 46 1 18 Adenium obesum s of growth under 50% shade ................................ ................................ ................................ .................. 47

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10 1 19 Interaction of fertilizer rat e and pot size on top dry weight of Adenium obesum ................................ ................................ ................................ ...... 57 1 20 Interaction of fertili zer rate and pot size on average weekly flower number of Adenium obesum ................................ ................................ ...................... 58 1 21 Interaction of fertilizer rate and pot size on visual plant quality of Adenium obesum ................................ ................................ ................................ ..... 59 1 22 Effect of 4 fertilizer levels on average weekl y flower number of Adenium obesum ................................ ................................ ................................ ...... 60 1 23 Effect of 4 fertilizer levels on average weekly flower number of Adenium obesum ................................ ................................ ................................ ...... 61 1 24 Adenium obesum ........... 67 1 25 Adenium obesum ........................ 67 1 26 Adenium obesum .......................... 68 2 1 Light levels in the greenhouse and under mist from May 2011 to May 2012. ..... 88 2 2 Terminal stem cuttings (tip cuttings) 8 to 10 cm in length. ................................ .. 89 2 3 Adenium cuttings in the mist area ................................ ................................ ..... 89 2 4 The effect of rooting compounds Hormodin 1, 2 and water c ontrol on rooting of Adenium obesum ................................ ................ 90 2 5 The effect of rooting compo 1:9 1:4, 2:3 4:1 and a water control on the rooting of Adenium obesum ................................ ................ 91 2 6 1:9 1:4 2:3 4:1 and a water control on the rooting of Adenium obesum ................................ ......... 92

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11 LIST OF ABBREVIATION S B boron C A calcium CAM crassulacean acid metabolism CO 2 carbon dioxide C U copper D S/ CM deci s eimens per centimeter EC electrical conductivity F E iron IAA indole 3 acetic acid IBA indole 3 butyric acid K + potassium K 2 O potassium oxide K 2 PO 4 phosphoric acid KG M 3 kilogram per cubic meter M G magnesium MG /L milligram per liter M M millimolar MMOL M 2 S 1 millimole per meter square per second MMOL /L millimole p er lier M N manganese M S/ CM millis eimens per centimeter N nitrogen N A sodium NAA naphthalene acetic acid

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12 NH 4 + ammonium NO 3 nitrate O 2 oxygen P phosphorus PAR photosynthetically active radiation S sulphur Z N zinc MOL M 2 S 1 micromole per meter square per second S/ CM microseimens per centimeter

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13 Abstract of Thesis Presented to the Graduate School of the University of Florida in Partial Fulfillment of the Requirements for the Degree of Master of Science THE EFFECT OF CULTURAL PRACTICES ON GROWTH, FLOWERING, AND ROOTING OF ADENIUM OBESUM By Kaitlyn Marie McBride August 2012 Chair: Richard J. Henny Cochair: Jianjun Chen Major: Horticulture Science Light and nutritional levels affected growth, flowering and visual quality of containeriz ed Adenium obesum or 50% shade in 1.25 L pots and top dressed with slow release fertilizer at 2, 4 or 6 grams of fertilizer per liter of soil volume. After 16 weeks, both cultivars produced the best growth, flowering and quality when fertilized with 6 grams/L rate under 30% shade. A second experiment with cultivar Red confirmed the previous results. Greenhouse 1.25 L and 3.0 L pots with four fertilizer rates (2, 4, 6, or 8 grams/L) showed the largest, most floriferous and best quality plants after 20 weeks when fertilizer rate was 6 or 8 g rams /L for plants in both 1.25 L and 3.0 L pots. Plants in 3.0 L pots produced significantly higher top and root dry weights than those in 1.25 L pots. Propagation tests using Adenium obesum cuttings showed best rooting occurred in cuttings treated with 8000 mg/L IBA or a combination of 8000 mg/L IBA plus 4000 mg/L NAA.

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14 CHAPTER 1 INTRODUCTION Literature review. Adenium spp. (Fosskal) Roemer & Schultes commonly referred to as Desert Rose, has become a successful new flowering tropical plant introduction over the past few years ( Dimmitt et al. 2009 ). The genus Adenium is a member of the plant family Apocyn aceae which includes other highly valued ornamental genera such as Allamanda cathartica (Allamanda) Catharanthus roseus L. (Vinca), Dipladenia sanderi L.(Dipladenia), Mandevilla Nerium oleander (Oleander) Plumeria sp. (Plume ria) and Tabernaemontana pachysiphon (Crape Jasmine). Adenium originates from Africa, south of the Sahara, from Senegal to Sudan and Kenya ( Plaizier 1980; Rowley undated) Adenium also grows as a native in Saudi Arabia, Oman and Yemen (Oyen, 2008). Despite confusion in its taxonomy, most Adenium are commonly referred to by species names. The most commonly recognized in the nursery trade inclu de: Adenium obesum, A. arabicum A. somalense A. multiflorum and A. swazicum Dimmitt et. al. (2009) indicates there are one species and 11 taxa. However, other authors limit the number of taxa to 5 or 6 (Rowley, 1999, Hargreaves, 2002, Brown, 2012, Plaizier, 1980) Das et al. (1999) studied the somatic chromosome number in six species of Adenium, specifically Adenium arabicum, A. o besum, A. multiflorum, A. somal ense, A. speciosum, and A. swazicum The somatic chromosome number of 2n = 22 was documented by Das et. al. (1999) in all species except A. swazicum which had 2n = 44 chromosomes. Similarly, Hastuti et. al. (2009) reviewed the morphology, karyotype and protein band pattern of six varieties including a species Adenium obesum plus Adenium

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15 obesum named cultivars Red L ucas Red F anta Cery H arry P otter, and White Bigben. They reported that all varieties tested had the same chromosome number 2n = 22. In the ir natural setting, Adenium vary in size from small shrubs up to tr ees more than 4.5 m tall ( Dimmitt et. al. 2009) Adenium hybrids have become very popular due to their bright and colorful flow ers, dark green leaves and uniquely sculptured caud ices T he Adenium caudex is a water storage organ that can have a unique and beautiful sculptural form. Caudex is defi ned as the axis of a plant, consistin g of stem and root (Rowley, 1987) and can be above or below g round (Dimmit t et. al. 2009) Most caudices have a distinct irregular swo llen base, (a swollen intersection of the trunk base and root), much of which is underground. Above ground the caudex can be globular to conical. Mat ure c aud ices can develop into large swollen trunk s and taper gradually upwards. T he branches are smooth, grayish green to brown, upright and irregularly spaced (Brown, 2012) Common Adenium flowers are usually pale pink to deep red on the petal margins, always fading to near white toward the throat (Dimmitt et. al., 2009) The white throat sometimes exhibits faint red nectar guides. The anther appendages ar e long, equaling or exceeding the throat. Flower siz e averages about 6 to 7 cm (2 inches) in diameter, but this is quite variable among clones (Dimmitt and Hanson, 1991) Recently, however, due to extensive worldwide breeding efforts, Adenium flo wer colors available now include all possible color combinations of white, pink, red, yellow and diameters exceeding 10 cm. In addition to flowers being striped, outlined in lavender or black, new double and triple flowered fo rms have been developed.

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16 Adenium leaf sizes are quite variable among and within species and shape ranges from narrow linear to quite broad Color varies from bright, shiny green to light, dull green (Dimmitt and Hanson, 1991) Six varieties of Adenium o besum studied had variable leaf lengths ranging from 6.4 cm to 8.7 cm and leaf widths were 1.6 cm to 2.9 cm (Hastuti et al., 2009) Many drought r esistant plants, such as cacti and succulents store water within their leaves and photosynthesize via crassulacean acid metabolism (CA M) Their stomata only open at night to fix CO 2 and then close during the day to reduce transpiration. Adenium leaves have a C3 photosynthetic metabolism and do not store water since t he presence of the caudex as the water storage organ precludes the neces sity of water storage in Adenium leaves and makes C3 metabolism possible (Rowley, 1987). T herefore t he stomata of Adenium are open during the day, which means with increasing temperatures CO 2 O 2 and water can flow out (Taiz and Zeiger, 2006, Raven et al., 2005) I n hot dry conditions photorespiration is increased often forcing lea f drop. Adenium require full sun for optimal growth and for flo wering according to McLaughlin and Garofalo ( 2002). Dimmitt et. al. (1998, 2009) suggests that mature specimens flower best in full sun for half of the day or filtered sun all day I nsufficient light intensity will cause the plant t o stretch and flower poo rly. He recommended cultivating plants in an area where the y will receive a minimum photosynthetically active radiation (PAR) of 185 mol m 2 s 1 light intensity and be maintaine d in a temperature range of 30 to 35 C (85 to 95 F) and high humidity during the growing season ( Dimmitt et. al. 2009). When grown in these conditions Adenium obesum are evergreen, and selected clones will flo wer throughout the winter in Arizona ( Dimmitt et. al. 2009 ). Adenium flowering habit is extremely variable and is influenced by both cultural and genetic factors. When grown under ample PAR light intensity ( 1 85 to 1480 m 2 s 1 )

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17 and with sufficient wa ter, some Adenium cultivars will flower for two to four months while some are nearly everblooming. Currently there is no scientific literature regarding Adenium cultural requirements in which plant studies have been conducted examining different rates of fertilizer or light intensity in controlled environmental conditions. While it is reported that Adenium respond well to regular fertilizing using a balanced fertilizer such as 20 20 20 plus micronutrien ts at a concentration of 200 mg/L nitrogen ( Dimmitt et al. 1998), data are not published. For more mature plants, it has been recommended to reduce or eliminate liquid fertilizer, but to continue slow release fertilizer (McLaughlin and Garofalo, 2002) but again this was not data based A limited number of nutritional studies on other genera within the family Apocynaceae have been published Plumeria rubra grown in pure silica sand in 35 cm x 12 cm containers (4L volume) were treated with a low and high nutrient level (2.4 g and 24.0 g, respectively, of 14 1 4 14 NPK of Osmocote ) in a glasshouse for 60 days during August and September (Huante et al., 1995) Results state more biomass was produced under high nutrient sup ply, while more biomass was allocated to the roots in low nutrient supply. There was no significant difference between root weights and root:shoot ratio be tween high and low treatments. Criley (2005) states that Plumeria sp. grew well in the full sun and r equired fertilizer ever y three to four months with 10N 30P 2 O 5 10K 2 O at about one pound per inch of trunk diameter and distributed around the plant to two feet beyond the foliage line. Mart (2012) reported that Mandevilla Vogue varieties are moderate feeders, responding best to a balanced fer tilizer at a rate of 100 to 200 mg/L and that f or large

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18 cont ainers a low to medium rate of a standard slow release fertilizer should be added at planting time. Deneke et. al. (1992) chose 8.3 kg of Osmocote (18 6 12) per cubic meter of potting medium in a study testing the effects of Sumagic (uniconazole) on the growth and flowering of Mandevilla Plants were also liquid fertilized weekly with 300 mg/L N from 20N 4.3P 16.6K (20 10 20). In an exp eriment conducted with Dipladenia sanderi L. (Plaza et al., 2009) fertigation was applied in a nutrient solution containing 6.0 mmol/L NO 3 4.0 mmol/L NH 4 + 0.8 mmol/L H 2 PO 4 3.0 mmol/L K + with a pH of 7.2 and an EC (electri cal conducti vity) of 1.2 dS/m. The experimental data indicated that Dipladenia sanderi L. fertigation should be adjusted to levels where NH 4 + is reduced and NO 3 H 2 PO 4 and K + concentrations are increased during January when maximum growth rate during gr eenhouse production occurred. Established landscape plants of Allamanda cathartica in an experiment testing four different fertilizers on growth and quality (Broschat et al., 2008) The fertilizer treatments consisted of no fertilizer, turf fertilizer 24 2 11 plus micronutrients, palm fertilizer (8 2 12 4 Mg) or controlled release palm (12 2 12 4 Mg) fertilizer plus micronutrients. Applications were made every three months. Results indicated that Allamanda did not benefit from the routine fertilization after being establi shed, even on infertile soils. The authors concluded that Allamanda in th e landscape may not benefit greatly from increasing fertilization Newly planted Nerium oleander required up to three applications of complete fertilizer per year at a rate of one pound of nitrogen per 1000 square feet (Popenoe, 2008) Well established plants of Nerium oleander similar to studies reported for

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19 Allamanda did not need additional inputs of fertilizer and absorb sufficient nutrients from lawn fertilizers in the landscape (Popenoe, 2008) Research with V inca ( Catharanthus roseus L.) showed that s eedlings can benefit from high concentrations of N (up to 32 mM) in the fertilizer while only low concentrations of P and K (0.25 mM) are needed (van Ierse et al., 1999) Ke ssler (1998) indicated that plug grown Vinca seedlings should be fertilized once or twice a week with 50 to 75 mg/L N, using 15 0 15 or calcium nitrate and potassium nitrate, and increased to 100 to 150 mg/L N when true leaves develop. Tabernaemontana pachysiphon Stapf was treated with three levels of Osmocote (no fertilizer, 3 kg /m 3 and 6 kg/m 3 ), two water regimes (regularly watering or waiting until wilt) and two light intensities, day light (low light) or addi tional illumination with Mercury Hg lamps (high light) where photon flux density varied between 1.2 and 1.4 mmol m 2 s 1 under high light and 0.3 and 0.7 mmol m 2 s 1 under low light (Hoft et al., 1996) Results indicated increasing nutrient supply had a positive effect on growth, drought stunted growth and high light intensity increased growth. Adenium are tropical and will not tolerate freezing temperatures. Stem tips can be damaged in temperatures be low 4 C (40 F), and if low temperature persists, it can cause severe damage and even plant death (McLaughlin and Garofalo, 2002 ). The same authors stated that if temp eratures routinely fall below 1 to 4 C (35 to 40 F) plants should be grown in containers s o they can be moved into pr otected areas during cold spells. In contrast, when temperatures exceed 37 C (100 F) most Adenium plants slow their growth and stop flowering ( Dimmitt and Hanson, in press).

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20 Propagation of Adenium can be accomplished by seed grafting, air layering, stem cuttings, and micropropagation. Seed propagation is most commonly used and is the least expensive method. Selected seed can be dusted with fungicide and sow ed in a sterile, free draining soil with a high percentage of sharp s and McLaughlin and Garfalo (2002) Brown (2012) states seeds should be placed on the surface of the soil mixture for germination and lightly covered Seeds will germinate within 1 to 2 weeks if kept at a soil temperature of 29 C (85 F). A month after germi nation seedlings can be ready for transplanting. Under proper conditions s eed grown plants can fl ower in as little as 12 months. Grafting is one of the most common methods of asexual propagation of Adenium ( Dimmitt et. al., 2009 ) When grafting, the scion and stock should be of similar size and vigor so that when the graft union heals the scion and the rootstock will stay in balance. In some cases a highly vigorous scion can overgrow the rootstock and the graph union will be disfigured ( Dimmitt et. al. 2009 ). Air layering is used to produce a few plants of relatively large size for special purposes (Hartmann et al., 2002) .The stem of the plant is cut to remove the phlo em and cambium to avoid premature healing. A layer of moistened sphagnum peat moss is wrapped around the stem and indole 3 butyric acid (IBA) can be added to the wound for stimulation of root initiation. Polyethylene film is then wrapped around the sphagnu m peat moss and th e branch and the ends sealed. Aluminum foil can be wrapped over the film to moderate temperatures. Adenium roots will form by this method after about 1 to 2 months. Once secondary roots are apparent the new plant can be removed and plante d. Air layering of Adenium is more likely to be successful during hot, humid

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21 weather ( Dimmitt et. al., 2009 McLaughlin and Garofalo, 2002) A review of the literature revealed little experimental based data regarding vegetative propagation via cutting s According to Brown (2012) Adenium plants can be started from cuttings. Dimmitt et al. (2009) stated that the optimum rooting medium temperature for Adenium cuttings is 27 to 32 o C (80 to 90F) however no data was presented. McLaughl in and Garofalo (2002) state t he easiest method of propagation is cuttings. Tip cuttings, preferably leafless, of about 5 inches long are dipped into rooting hormone with fungicide and rooted in a 1:3 mix of damp Canadian peat:perlite. In contrast, Brown ( 2012) and Dimmitt et. al. (2009) suggest s that cuttings should have leaves, because leaves promote faster rooting and g rowth once cuttings are rooted. Vegetative stem cuttings need to be mist ed frequently, have a heated mist bench, and be provided 30 % to 5 0% shade. Light intensity is an important factor affecting the growth and development of a cutting. With too much or too little light, rooting percentage can decline (Joiner et al., 1981) In order to stimulate adventitious root growth in cu ttings, auxins can be utilized. The most common auxins used are indole 3 acetic acid (IAA), indole 3 butyric acid (IBA) and naphthalene acet ic acid (NAA). Combinations of IBA and NAA are effective with many plant materials. The more difficult to root material should be treated with higher concentrations of the compounds than less difficult to root species (Joiner et al., 1981) Micropropagation (tissue culture) can produce true to type explants, with rapid multiplication in vitro and with lower space requirements and production costs. Experiments in micropropagation of Adenium obesum showed significant improvement in the frequency of rooting (Xiaomei et al., 2003) significant multiplication of shoots at a

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22 high frequency (Kanchanapoom et al., 2010) and induced callus (Liu et al., 2004) in Adenium obesum cultures under in vitro conditions These results point to auxins having a significantly positive effect on rooting Adenium obesum cuttings To our knowledge, micropropagation of Adenium is not a widely est ablished commercial technique at this time. A range of architectural forms, growth habit s and flower colors on Adenium plants are available for sale globally via the internet; however, there is little documentation or research for cultural practices that m ight make Adenium more adap table for commercial production Because of this lack of information in the scientific literature t he following study was conducted to determine effects of light an d nutritional levels on growth and flowering of Adenium obesum that are in commercial production in Florida. In addition, studies of factors affecting vegetative cutting propagation were also conducted.

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23 CHAPTER 2 EFFECTS OF NUTRITION AND LIGHT LEVELS ON GROWTH AND FLOWERING OF ADEN IUM OBESUM Materials and Methods Experiment 1 1 One hundred eighty established Adenium obesum liners in 72 cell trays were obtained April 20, 2010 from Oglesby Plants International, Inc. (Altha, FL 32421). Ninety plants of two culti rooted in Oasis Rootcubes media ( Smithers Oasis North America Kent, OH 44240) ; 13 weeks old. O n a rrival, all plants were 10 to 15 cm in height and some had second ary shoots. The plants were potted in 1.25 L (15.2 cm or 6 inch diameter) azalea pots, with Fafard Promix 52 media (60% pine bark, 24% Canadian sphagnum peat, 8% perlite, and 8% vermiculite; Conrad Fafard Inc., Agawam, MA 01001) on April 22, 2010. After potting, all plants were tipped to 5.0 to 7.5 cm in h eight and Nutricote Plus (18N 2.6P 6.6K) controlled release fertilizer (Chisso Asahi Fertilizer Co., LTD Tokyo, Japan) was applied at 2, 4, 6 grams/L of soil volume per pot. Pots were placed onto ground cover outdoors under natural day length and temperature conditions at MREC Apopka, FL. Light treatments consisted of 0% (full sun), 30 % or 50% (light intensity: 1850, 1202, or 351 m 2 s 1 respectively ) shade provided by black woven polypropylene shade cloth. Plants were placed in a completely randomized design under each light level on April 23, 2010. Flower buds were removed for one month after planting to promote root and sho ot growth

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24 Data collected throughout the experiment included bi weekly light levels recorded at canopy height with a Li Cor Quantum Radiometer Photometer (Model No. LI 185B, Lincoln, Nebraska 68504) plant canopy height and width, leaf length and width, days to fi rst open flower, total weekly flower cou nts, and overall plant quality. Plant canopy height and width and leaf length and width were recorded after 16 weeks. Plant quality was taken at termination (Augu st 23, 2010) of the experiment. Visual q uality rating was based on form, foliage and flowers : 1 = poor ; 2 = fair; 3 = s aleable; 4 = good; 5 = excellent The experimental design was a factorial analysis with two cultivars, three fertilizer levels and three light levels with ten replications per treatment. Da ta were analyzed using ANOVA procedures of the SAS program (SAS Institute Inc., Cary, NC 27513). Parameters with means showing significant differences were subjected to regression analysis. Results and Discussion Experiment 1 1 Canopy height o fertilizer levels increased (Table 1 1). Fertilizer had a signif icant effect on canopy height, and canopy width, while s hade level affect ed canopy h eight, width, leaf length and leaf Ice (Table 1 2 ). Leaf length and width increased significantly as shade increased but showed no significant difference in response to change in fertilizer levels. There was a significant interaction of fertilizer rate and light level on average week ly flower number (Figure1 1) and visual plant quality ( Figure 1 2 ) Flower number declined as shade levels increased, h owever, higher fertilizer levels resulted in more flowers. Visual p lant quality was the highest under 30% shade an d decreased under 0 %

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25 ( F igure 1 6 ) and 50% shade ( Figure 1 8 ) Visual p lant quality increased as fertilizer rates increased. The best quality plants were produced under 30% shade at fertilizer rates of 4 or 6 grams/L per pot (Table 1 1; Figure 1 7 ). Canopy height and width of Adenium obesum fertilizer and shade levels increased ; whereas leaf length and width increased significantly as shade levels increased but did not respond to fertilizer level ( Table 1 3 ). Tabernaemontana pachysiphon Sta pf. grown under high light intensity ( photon flux density varied between 1.2 and 1.4 m mol m 2 s 1 ) and ample water supply increased in height increment by approximately 20% (Hoft,1996). Our data showed that the best growth and flowering of Adenium obesum Red' and 'Ice Pink' oc curred between 740 1480 m 2 s 1 This is in contrast to Dimmitt et. al. (2009 ) who suggested a minimum of 185 m 2 s 1 was adequate for Adenium growth. There was a significant interaction on average weekly flower number ( Figure 1 2 ) and visual quality ( Figure 1 4 ). Flowe r number was greater at the highest fertilizer rate and slightly better under 30% shade compared to 0% and 50% shade levels Visual p lant quality was greatest with 6 grams/L of fertilizer and steadily decreased from 0% ( Figure 1 8 ) to 50% shade ( Figure 1 1 0 ). Overall, visual plant quality was highest under 30% shade and 6 gr ams/L of fertilizer ( Figure 1 9 ).

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26 Data Experiment 1 1 Table 1 1. Adenium obesum three l ig ht levels after 16 weeks (April to August 2010). Shade (%) Canopy Height (cm) Canopy Width (cm) Leaf Length (cm) Leaf Width (cm) Average Flower Number z Visual Quality (1 5) y 0 20.4 18.0 5.2 1.8 2.8 2.6 30 23.9 21.0 5.6 2.0 3. 0 3.3 50 26.2 24.5 5.6 2.3 1.2 2.0 Fertilizer (grams/L) 2 19.2 15.6 5.5 2.0 1.4 2.2 4 24.2 21.4 5.4 2.0 2.3 2.8 6 26.6 25.8 5.6 2.0 3.4 3.0 Significance x Shade ** ** ** ** ** ** Fertilizer ** ** NS NS ** ** Shade*Fertilizer NS NS NS NS ** z Average weekly flower count. y Visual quality where 1 = unsalable, 3 = saleable, 5 = excellent quality. x NS, **, indicate non significant or significance at the P 0.01 or 0.05, respectively.

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27 Table 1 2 Effect of shade and fertilizer level on growth of Adenium obesum August 2010). Fertilizer (grams/L) Shade (%) Canopy Height (cm) Canopy Width (cm) Leaf Length (cm) Leaf Width (cm) 2 0 16.2 13.1 5.2 1.8 2 30 20.2 16.4 5.8 2.0 2 50 21.9 17.8 5.5 2 4 0 21.4 17.8 5.2 1.8 4 30 24.6 21.7 5.2 2.0 4 50 26.8 25.0 5.7 2.3 6 0 23.8 23.0 5.4 1.8 6 30 27.0 24.8 5.9 2.0 6 50 29.3 30.0 5.8 2.2 Significance z L** L** L** L** z Regression analysis where L** indicate: Linear significance at the 0.01 level.

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28 Figure 1 1. Interaction of three fertilizer levels and three light levels on average weekly flower number of Adenium obesum Interaction Significance at P = 0.0003 0 0.5 1 1.5 2 2.5 3 3.5 2 4 6 Average Weekly Flower Number Fertilizer Rate (grams/L) Full Sun (0%) 30% 50%

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29 Figure 1 2 Interaction of three fertilizer levels and three light levels on visual quality rating of Adenium obesum after 16 weeks. Interaction Significance at P = 0.0316 1 1.5 2 2.5 3 3.5 4 4.5 2 4 6 Visual Quality Rating Fertilizer Rate (grams/L) Full Sun (0%) 30% 50%

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30 Table 1 3 Adenium obesum and visual quality as affected by three fertilizer and three lig ht levels after 16 weeks (April to August 2010). Shade (%) Canopy Height (cm) Canopy Width (cm) Leaf Length (cm) Leaf Width (cm) Average Flower Number z Visual Quality (1 5) y 0 20.3 22.8 7.0 1.6 1.1 2.9 30 22.1 27.4 7.7 1.8 1.6 3.2 50 25.2 34.4 7.6 1.8 0.6 2.4 Fertilizer (grams/L) 2 20.4 23.1 7.4 1.7 0.3 2.3 4 23.0 28.0 7.4 1.8 1.1 2.8 6 24.1 33.0 7.6 1.6 1.9 3.3 Significance x Shade ** ** ** ** ** ** F ertilizer ** ** NS NS ** ** Shade*Fertilizer NS NS NS NS ** ** z Average weekly flower count y Visual quality where 1 = unsalable, 3 = saleable, 5 = excellent quality. x NS, **, indicate non significant or significance at the P 0.01 or 0.05, respectively.

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31 Table 1 4 Effect of shade an d fertilizer level on growth of Adenium obesum August 2010). Fertilizer (grams/L) Shade (%) Canopy Height (cm) Canopy Width (cm) Leaf Length (cm) Leaf Width (cm) 2 0 16.3 18.1 7.1 1.6 2 30 19.5 21.3 7.8 1.8 2 50 25.3 30.0 7.4 1.8 4 0 21.2 22.4 7.0 1.6 4 30 23.0 28.5 7.7 1.8 4 50 25.1 34.6 7.7 1.9 6 0 23.4 27.9 7.2 1.5 6 30 23.8 32.5 7.7 1.8 6 50 25.2 39.2 7.9 1.8 Significance z L** L** L** L** z Regression analysis where L** indicates: Linear significance at the 0.01 level.

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32 Figure 1 3 Interaction of three fertilizer and light levels on average weekly flower number of Adenium obesum 16 weeks. Interaction Significance at P = 0.0003 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 2 4 6 Average Wekly Flower Number Fertilizer Rate (grams/L) Full Sun (0%) 30% 50%

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33 Figure 1 4 Interaction of three fertilizer levels and three light levels on visual quality rating of Adenium obesum 16 weeks. Interaction Significance at P = 0.0001 1 1.5 2 2.5 3 3.5 4 2 4 6 Visual Quality Rating Fertilizer Rate (grams/L) Full Sun (0%) 30% 50%

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34 Figure 1 5 Adenium obesum after 16 weeks (April to August) of gro wth under full sun at three different fertilizer rates Figure 1 6 Adenium obesum after 16 weeks (April to August) of growth under 30% shade at three different fertilizer rates.

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35 Figure 1 7 Adenium obesum after 16 weeks (April to August) of growth under 50% shade at three different fertilizer rates. Figure 1 8 Adenium obesum (April to August) of growth under full sun at three different fertilizer rates

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36 Figure 1 9 Adenium obesum (April to August) of growth under 30% shade at three different fertilizer rates Figure 1 10 Adenium obesum (April to August) under 50% s hade at three different fertilizer rates 6 g/L

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37 Materials and Methods Experiment 1 2 Fifty four uniform well rooted stem cuttings of Adenium obesum approximately 7 to 9 cm in length with several developing bud s were potted into 1.25 L (15.2 cm or 6 inch diameter) containers filled with Fafard 2 mix (65% Peat, 20% Perlite, 15% Vermiculite by volume; Conrad F afard Inc., Agawam MA 01001 ) on July 29, 2011. Nutricote Plus (18 6 8; Chisso Asahi Fertilizer Co., LTD Tokyo, Japan) was applied at rates equivalent t o 2.0, 4.0, or 6.0 grams per liter of soil volume and placed on ground cover beds outdoors under natural day length and temperature conditions at MREC Apopka, FL. The fertilizer treatments were reapplied 12 weeks after initiation. Light treatments consiste d of 0 % 30% or 50% shade provided by black woven polypropylene shade cloth which provided light levels equivalent to 1480, 1017, 555 mol m 2 s 1 (Figure 1 11 ) respectively at the beginning of the experiment, as measured by a Li Cor Quantum Radiometer Pho tometer (Model No. LI 185B Lincoln, Nebraska 68504) Light levels measured as photosynthetically active radiation ( PAR ) were recorded every two weeks at canopy height throughout the course of the experiment To increase lateral branching, terminal buds were removed from all plants on August 22, 2011 and any escaped branches were tipped weekly until September 19, 2011. Twelve weeks after initiation of the experiment, open flowers were first observed and weekly flower counts began (October 21, 2011) and en ded eight weeks later at termination. The experiment was terminated December 12, 2011 and measurements of canopy height and width, leaf length and width and flower count were made. Stem caliper was measured at the soil line using a Vernier Caliper (General Tools Mfg, New York, NY 10013) and plants were rated for visual quality on a scale of 1 through 5, wh ere 1 = poor; 2 = fair; 3 = saleable ; 4 = good; 5 = excellent Tops of plants were then removed at the soil line

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38 and weighed on a Scout Pro scale (Model N o. SPE2001, Ohaus Corporation, Pine Brook, NJ 07054). Soil remaining on roots was washed away; roots were allowed to dry and then wer e weighed using the same scale. The tops and roots were bagged separately in brown paper bags and dried in a TD Vac Dryer ( Heat Pipe Technology, Gainesville, FL 32609) at 73C (165F) for two weeks. Dry weights were recorded using a Scout Pro scale. Plants were placed in a 3x3 factorial design with 6 replications (each pot was an experimental unit) ( Figure 1 15 ) Data were an alyzed using ANOVA procedures of the SAS program (SAS Institute Inc., Cary, NC 27513). Parameters with means showing significant differences were subjected to regression analysis. Results and Discussion Experiment 1 2 After 20 weeks of growth, canopy heigh t and width of Adenium increased significantly in response to higher ferti lizer and shade levels ( Table 1 5 ). Plants were slightly spreading in growth habit with a canopy height to width rati o that ranged from 0.9 to 0.96 to 1.0. Plants gr own under 50% shade ( Figure 1 18 ) were somewhat leggy (long internodes) and grew in a more spreading fashion while those in full sun ( Figure 1 16 ) were more compact. The tallest plants (25.7 cm) were under 50% shade and 6 grams/L of fertilizer ; whereas t h e smallest canopy height (14.2 cm) occurred at 2 grams/L fertilizer and 0% shade ( Table 1 6 ) Similarly, the smallest canopy width was 16.2 cm at 2 grams/L of fertilizer at 0% shade, while the largest canopy width was 29.8 cm at 6 grams/L of fertilizer at 50% shade. Leaf size was not affected by fertilizer or shade level. Average leaf width was a uniform 1.8 cm and leaf length ranged from 7.4 to 7.9 cm (Table 1 2). Stem caliper ranged from 1.9 to 2.3 cm and was significantly greater at higher fertilizer l evels but was

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39 not affected by shade level. Increase in top dry weight was associated with higher fertilizer and/or shade levels (Table 1 2). Plants fertilized with 2 grams/L of fertilizer significantly increased in top dry weight as shade levels increase d from 0 to 50% ( Table 1 6 ). Those fertilized with 4 grams/L of fertilizer increased in top dry weight from 0 % to 30% shade but showed a slight decrease from 30 % to 50% shade ( Table 1 6 ). Plants treated with 6 grams/L showed almost identical top dry weigh ts regardless of shade level. At all three shade levels top dry weights increased as fertilizer levels increased, but shade level did not have a significant effect (Appendix A ; Figure 1 13 ). Root dry weight was greatest in the full sun and highest fer tili zer treatments (Table 1 2). Plants grown at the same light level showed increasing root dry weights as fertilizer level increased ( Table 1 6 ). As shade levels increased root dry weight decreased at all fertilizer levels ( Table 1 6 ). Top dry weight exceede d root dry weight in all treatments ( Table 1 6 ). Overall, the top to root weight ratio was 1.8, 2.2 and 3.2 to 1.0 at 0 % 30 % and 50% shade levels; and, 1.7, 2.3 and 2.5 to 1.0 at the 2, 4, or 6 gram/L fertilizer rates respectively. The smallest difference in shoot to root ratio was 1.4 at the 2 grams/L fertilizer rate at either 0 % or 30% shade while the largest shoot to r oot ratio was 3.8 recorded at 6 grams/L and 50% shade. Weekly flower counts increased significantly with higher fertilizer rates but flow er number decreased as shade level increased. The highest average weekly flower counts observed were 4.5 and 4.9 flowers at 6 grams/L of fertilizer at 0 % ( Figure 1 12 ) and 30% shade ( Figure 1 13 ) respectively ( Table 1 6 ). In contrast, plants grown at the

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40 2 grams/L fertilizer rate produced the lowest average weekly flower count of 0.3 at 50% shade ( Figure 1 14 ) while the second lowest was 1.3 flowers at 4 grams/L of fertilizer at 50% shade. Plants with the highest number of flowers ha d the appearance similar of an a zalea in that the canopy was covered with flowers and the leaves were mostly hidden. Plants fertilized with 6 grams/L of fertilizer in 30% shade or in the full sun had higher flower numbers than those under 50% shade. Overall best plant quality w as at the 6 gram/L fertilizer rate under 30% shade ( Figure 1 17 ). At these conditions plants had a visual quality rating of 4.4 which was between good and excellent quality. All of the three poorest quality ratings occurred at the lowest fertilizer level r egardless of shade level. The plants in these treatm ents were not considered to be of salable quality.

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41 Data Experiment 1 2 Ta ble 1 5 Effect of three shade and fertilizer levels on growth, flowering and visual quality of Adenium obesum 20 we eks (July to December 2011). Shade (%) Canopy Height (cm) Canopy Width (cm) Leaf Length (cm) Leaf Width (cm) Caliper (cm) Top Dry Wt. (g) Root Dry Wt. (g) Average Flower Number z Visual Quality (1 5) y 0 18.1 20.5 7.4 1.8 2.0 15.0 8.5 3.4 3 .1 30 20.8 22.3 7.5 1.8 2.1 17.2 8.0 3.0 3.6 50 24.3 25.3 7.9 1.8 2.1 17.9 5.6 1.2 3.1 Fertilizer (grams/L) 2 17.8 17.7 7.4 1.8 1.9 9.4 5.5 1.5 2.4 4 22.2 23.1 7.6 1.8 2.0 16.9 7.2 2.1 3.2 6 23.2 27.2 7.8 1.8 2.2 23.6 9.3 3.8 4.0 Significance x Shade ** ** NS NS NS ** ** ** Fertilizer ** ** NS NS ** ** ** ** Shade x Fertilizer NS NS NS NS NS NS NS NS NS z Average weekly flower count y Visual quality rating where 1 = unsalable, 3 = s aleable, 5 = excellent quality. x NS, **, indicate non significant or significance at the P 0.01 or 0.05, respectively.

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42 Table 1 6 Effect of shade and fertilizer level on plant growth, flowering and visual quality of Adenium obesum 20 weeks (July to December 2011). Fertilizer (grams/L) Shade (%) Canopy Height (cm) Canopy Width (cm) Leaf Length (cm) Leaf Width (cm) Caliper (cm) Top Dry Wt. (g) Root Dry Wt. (g) Average Flower Number z Visual Quality (1 5) y 2 0 14.2 16.2 7.1 2.0 2.0 7.9 5.7 2.6 2.4 2 30 17.2 17.0 7.0 1.6 2.0 8.8 6.4 1.7 2.4 2 50 22.2 20.0 8.0 1.8 1.9 11.7 4.4 0. 3 2.5 4 0 19.0 19.4 7.5 1.8 1.9 13.6 7.9 2.6 2.9 4 30 22.5 23.8 7.7 1.9 2.2 18.9 7.8 2.5 3.8 4 50 25.2 26.2 7.7 1.8 2.1 18.2 6.0 1.3 2.9 6 0 21.0 25.8 7.5 1.8 2.3 23.3 11.9 4.5 3.9 6 30 22.8 26.0 7.8 1.9 2.2 23.8 9.8 4.9 4.4 6 50 25.7 29.8 7.9 1.8 2.2 23.7 6.3 2.0 3.8 Significance x L** L** NS NS L** L** L** L* L** z Average weekly flower count. y Visual quality rating where 1 = unsalable, 3 = saleable, 5 = excellent quality. x Regression analysis where NS, L** and L* indicates: Not significant, linear significance at the 0.01 level, and linear significance at the 0.05 level, respectively.

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43 Figure 1 11 Light levels of 0 % 30 % or 50% shade from July to December 2011. Figure 1 12 The effects of increasing fe rtilizer rates on average weekly flower number of Adenium obesum grown under 0% shade, from first open flower to termination. 0 500 1000 1500 2000 2500 20-Jul 20-Aug 20-Sep 20-Oct 20-Nov 2s 1 Experimental Time Frame Full Sun 30% 50% 0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0 Average Weekly Flower Number 2 grams/L 4 grams/L 6 grams/L

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44 Figure 1 13 The effects of increasing fertilizer rates on the average weekly flower number of Adenium obesum grown under 30% shade, from first open flower to termination. 0.0 2.0 4.0 6.0 8.0 10.0 12.0 Average Weekly Flower Number 2 grams/L 4 grams/L 6 grams/L

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45 Figure 1 14 The effects of increasing fertilizer rate on the average weekly flower number of Adenium obesum grown under 50% shade, from first open bloom to termination. Figure 1 15 Experimental Design was 3 shade levels and 3 fertilizer levels with 6 replications of Adenium obesum 0 1 2 3 4 5 6 7 8 Average Weekly Flower Number 2 grams/L 4 grams/L 6 grams/L

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46 Figure 1 16 Adenium obesum 1.25 L pots after 20 weeks of growth in full sun at three different fertilizer rates. Figure 1 17 Adenium obesum Red in 1.25 L pots after 20 weeks of growth under 30% shade at three different fertilizer rates.

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47 Figure 1 18 Adenium obesum Red in 1.25 L pots after 20 weeks of growth under 50% s hade at three different fertilizer rates.

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48 Materials and Methods Experiment 1 3 Ninety six Adenium obesum stem cuttings grown in 50 cell trays for 11 weeks were transfe rred to forty eight 1.25 L (15.2 cm) and forty eight 3.0 L (20.3 cm) azalea pots ( F igure 1 24 ) filled with Fafard 2 mix (65% Peat, 20% perlite, and 15% vermiculite by volume; Conrad Fafard Inc., Agawam, MA 01001). The fertilizer rates for both the pot sizes were equivalent to 2.0, 4.0, 6.0, or 8.0 grams of Nutricote per liter of soil vol ume regardless of pot size. Therefore, the 1.25 L pots were fertilized by top dressing with 2.5, 5.0, 7.5, or 10.0 grams of Nutricote Plus (18N 6P 8K; Chisso Asahi Fertilizer Co., LTD Tokyo, Japan) while the 3.0 L pots were treated with 6.0, 12.0, 18.0, or 24.0 grams per pot. At the time of potting on July 25, 2011, terminal shoot tips and any developing flower buds on each liner were removed to promote branching. The plants were placed in a complete randomized block design in a greenhouse covered with a cl ear double polyethylene roof w ith a PAR light intensity of 1017 mol m 2 s 1 and natural photoperiod. Light levels were recorded at canopy height bi weekly with a Li Cor Quantum Radiometer Photometer (Model No. LI 185B, Lincoln, Nebraska 68504) throughout the 20 week duration of this experiment. The first flowers opened 11 weeks after initiation of the experiment (September 19, 2011) at which time weekly flower counts were started and continued for 10 weeks until the experiment was t erminated on December 15, 2011. Final data collected consisted of canopy height and width, leaf length and width, stem caliper at the soil line, final weekly flower number, top dry weight, and root dry weight and visual plant quality rating. Visual quality rating was based on: 1 = poor; 2 = fair; 3 = saleable; 4 = good; 5 = excellent Stem caliper was measured with a Vernier Caliper (General Tools Manufacturing, New York, NY 10013) after which the plant top was cut off at the soil

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49 line. Each plant top was then manually divided into its leaf, flower and stem components which were then placed separately into brown paper bags for oven drying. Both top and root tissue was dried in a TD Vac Dryer (Heat Pipe Technology, Gainesville, FL 32609) at 73C (165F) for two weeks. Roots were removed from the pots and the soil was washed off. Cleaned root s were allowed to air dry for 1 to 2 hours before being placed into brown paper bags Root d ry weight was then recorded using a Scout Pro scale (Model No. SPE2001, Ohaus Corporation, Pine Brook NJ 07054). Final top dry weight was determined by combining the weights of leaves, flowers, and stems. For mineral analysis of dried plant tissue, three random samples of dried leaves, stems, flowers, and roots were taken from each at fertilizer rate an d each pot size resulting in a total of 96 samples that included 48 from 1.25 L and 48 from 3.0 L pots. Dried tissue was ground in a stainless steel Wiley Mill Grinder (Arthur H Thomas Co. Philadelphia, PA 08085) to pass through a 60 mesh screen. Tissue wa s then analyzed for macro and micronutrients at Midwest Laboratories Inc., (Omaha Nebraska 68144) on March 16, 2012. Mineral elements of nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), sulfur (S), iron (Fe), manganese (Mn), coppe r (Cu), zinc (Zn), and sodium (Na) in the flowers, leaves, roots, and stems of Adenium obesum Every three weeks during the experiment, soi l soluble salts and pH were record ed by randomly selecting 3 pots from each fertilizer level and from each pot size (24 samples). For analysis, sample s were collected by pouring 100 to 120 ml of deionized water into 1.25 L pots or 200 to 250 ml into 3.0 L pots. Fifty milliliters of solution was collected from the runoff from each sample p ot. Soluble salts were then

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50 record ed using a Corning Conductivity Meter (Corning Inc. Corning, NY 14831) U nits of EC milliseimens per centimeter (mS/cm) or microseimens per centimeter (S/cm) were recorded. The pH of the same s olution was determined using an Accumet Basic pH Meter (Model No. AB15, Fisher Scientific Hanover Park, IL 60133 ). The experimental design was a factorial analysis with two pot sizes and four fertilizer levels with 12 replications per treatment. Data were analyzed using ANOVA procedures of the SAS program (SAS I nstitute Inc., Cary, NC 27513). Parameters with means showing significant differences were subjected to regression analysis. Results Experiment 1 3 Pot size had a significant effect on canopy height and width, leaf length and width, calip er, top dry weight, root dry weight, average weekly flower number and final plant quality of data collected while fertilizer level had a significant effect on all data types except leaf length and width ( Table 1 7 ). Canopy height, canopy width and stem cal iper were significantly larger in 3.0 L pots versus 1.25 L pots regardless of fertilizer rate. Canopy height, canopy width and leaf width increased in a significant linear manner at increasing fertilizer levels regard less of pot size ( Table 1 8 ). The bigge st difference in height occurred at treatment 2 grams/L where 3.0 L potted plants were 30% larger than 1.25 L potted plants. Canopy width was always larger than canopy height as plants showed a spreading growth habit ( Table 1 8 ). Stem caliper was larger i n 3.0 L pots compared to 1.25 L pots regardless of fertilizer level. Caliper increased with each higher fertilizer level in 1.25 L pots, but for plants grown in 3.0 L pots the largest caliper (3.4 cm) resulted from application of 4 grams/L of fertilizer an d was smaller at the 2, 6 and 8 grams/L of fertilizer ( Table 1 8 ). The largest stem caliper (2.6 cm) in 1.25 L pots was at the 8 grams/L fertilizer rate.

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51 Leaf length and width were affected by pot size but not by fertilizer rate ( Table 1 7 ) Plants in 3.0 L pots had leaf lengths comparable to plants in 1.25 L pots but leaf widths were significantly narrower in 3.0 L pots. Leaves were longer than wide as the leaf length to width ratio was in the range of 4.2 to 4.4 across all treatments. Root dry weight si gnificantly increased at higher fertilizer rates regardless of pot size. The larger dry weights were produced in 3.0 L pots compared to 1.25 L pots at all fertilizer levels ( Table 1 8 ). Interaction of pot size and fertilizer level significantly affected t op dry weight ( Figure 1 19 ), average weekly flower number ( Figure 1 20 ) and plant visual quality ratings ( Table 1 7 ; Figure 1 21 ). Top dry weight increased as fertilizer level increased but the rate of increase slowed between the 6 and 8 grams/L levels ( Fi gure 1 19 ). Final top dry weight of p lants in 3.0 L pots was double that measured in 1.25 L pots. Average weekly flower count increased with higher fertilizer rates ( Figure 1 22 1 3e) Average weekly flower number in 3.0 L pots was more than double that of 1.25 L pots and flower number increased with fertilizer levels ( Table 1 7 ) Maximum flower counts were achieved from plants grown at higher fertilizer rates in bo th 1.25 L and 3.0 L pots. The great est increase in average flower number observed was betwe en the 2 and 4 grams/L fertilizer rates. Visual quality for plants in 1.25 L pots was best at the 6 grams/L ( Figure 1 25 ) treatment and for 3.0 L pots it was best for 4 and 6 grams/L fertilizer rates (Figure 1 2h). For both pot sizes the lowest visual qua lity was at the 2 grams/L fertilizer rate Plant visual quality was higher in 3.0 L pots than 1.25 L and increased as fertilizer rate increased from 2 grams/L to 6 grams/L rate but the rate of increase decreased

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52 somewhat at the higher fertilizer rate. Best overall plant quality rating was at 6 grams/L fertilizer rate for 1.25 L pots and at 4 and 6 grams/L for 3.0 L pots. Soluble Salts and pH There was a significant interaction of fertilizer rate and pot size on soluble salt concentration (Appendix A: A 10 ) and pH balance (Appendix A; A 11 ) As fertilizer rates increased for Adenium alt levels increased ( Table 1 9 ). The total s oluble salt levels of 700 to 18 5 0 S /cm are within the normal range for production. Based on our data, good quality Adenium plants can be prod uced at a soluble salts reading of 1500 to 20 00 S /cm. The pH decreased with increasing fertilizer levels, indicating that there was an acidic respo nse to the fertilizer used. Soluble salt concentration was higher at 3.0 L pot size Mineral Nutrient Analysis Results Analysis of flowers showed N a uniform 1.5%, Mg ranged from 0.24 to 0.25%, Ca from 0.32 to 0.35%, S from 0.15 to 0.16%, Fe from 20.2 t o 31.0 mg/L, B from 21.2 to 23.0 mg/L, and Zn from 17.3 to 19.7 mg/L ( Table 1 10 ). The levels of each of these nutrients in flowers were not significantly different regardless of fertilizer or pot size treatments. Differences in P concentrations ranged fro m 0.19 to 0.22%, K from 2.2 to 2.4%, Na from 0.7 to 0.13%, and Cu ranged from 6.9 to 9.3 mg/L across pot sizes ( Table 1 10 ). P and K levels increased as pot size increased, while Na and Cu significantly d ecreased as pot size increased. At higher fertilizer levels Na concentration in flowers decreased from 0.13% to 0.07%. There was a significant interaction of pot size and fertilizer rate effect for Mn concentration; flower Mn concentration increased with pot size and fertilizer rate (Appendix A; A 15 )

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53 In leaf tissue analysis, the concentrations of N, P, K, S, Na, Fe, Mn, Cu, and Zn were significantly different ( Table 1 11 ). The concentrations ranged from 1.9 to 2 .4% for N, 0.09 to 0.12% P, 0.45 to 0.65% K, 0.23 to 0.25% S, 0.35 to 0.67% Na, 35.7 to 48.2 m g/L Fe, 86.0 to 1 17.0 mg/L Mn, 39.0 to 44.7 mg/L B, 4.8 to 5.6 mg/L Cu, and 9.0 to 10.4 mg/L Zn ( Table 1 11 ). Concentrations of N, P, K, Na, Fe, Cu, and Zn were significantly affected by pot size. In the larger pot sizes the concentration of N, P, K, and Fe increased, while leve ls of Na, Cu and Zn decreased. At increasing fertilizer rates concentrations of N, P, S, Fe, and Mn significantly increased whereas K and Na levels decreased. Concentrations of Ca, Mg, and B in leaf tissue did not differ significant ly among the treatments There was a significant interaction between pot size and fertilizer rate for S concentration in which the concentration of S in the leaves increased at larger pot size and higher fertilizer level (Appendix A; Figure 1 3l) Stem tissue mineral analysis showed significant differences for N, P, K, Mg, Ca, S, Na, and B concentrations ( Table 1 12 ). Concentrations of N in stem tissue ranged from 1.5 to 2.1%, 0.10 to 0.14% P, 0.89 to1.34% K, 0.53 to 0.78% Mg, 0.82 to 1.06% Ca, 0.19 to 0 .25% S, 0.36 to 0.54% Na, 28.8 to 36.8 mg/L Fe, 24.7 to 25.7 mg/L Mn, 26.3 to 28.7 mg/L B, 8.1 to 8.4 m g/L Cu, and 25.0 to 34.5 mg/L Zn. Concentration of P, K, and S in stem tissue was significantly higher for plants grown in larger pots whereas Ca, Na, an d B content decreased significantly as pot size increased ( Table 1 12 ). Analysis of stem tissue also showed that as fertilizer rates increased, N, P, K, and S concentrations increased significantly, while Mg, Ca, and Na content decreased significantly

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54 A nalysis of root mineral concentration s showed that N ranged from 1.5 to 2.5%, 0.13 to 0.21% P, 1.6 to 2.8% K, 0.7 to 0.98% Mg, 0.34 to 0.46% Ca, 0.18 to 0.27% S, 0.10 to 1.08% Na, 202.0 to 353.0 mg/L Fe 18.0 to 29.2 mg/L Mn, 15.0 to 19.3 mg/L B, 7.8 to 10 .7 mg/L Cu, and 21.7 to 24.0 mg/L Zn. As pot size increased N, P, K, Mg, and S levels in root tissue increased significantly ( Table 1 13 ). At increasing fertilizer levels the concentration of N, P, K, Mg, S, and B significantly increased. However, Ca conce ntration was higher at the 2 grams/L and 8 grams/L fertilizer rates and lower at the 4 and 6 grams/L fertilizer rates ( Table 1 13 ). There was a significant interaction for pot size and fertilizer rate on B content (Appendix A ; Figure 1 3 m ). As fertilizer a nd pot size increased the concentration of B also increased. Roots had higher Fe concentration than the other tissues, but Fe concentrations in the stem, leaves and flowers were similar indicating there was sufficient Fe in the potting media. The almost equal amount of Fe in stem, leaves, and flowers suggests that Adenium requirement for Fe is in range of 30 to 40 mg/L. Comparing Mn and S concentrations in root tissue with those in leaf tissue, leaves had much higher concentrations of both elements. Con sidering that both Mn and B are less mobile in plants, the higher concentrations of both nutrients suggest Adenium require relatively h igh levels of Mn and S for growth. This is the first report of nutrient concentrations in Adenium flowers, leaves, stems, and roots. The combined tissue analysis mineral content of N, P, K, and Ca of Adenium was comparable with mineral tissue analysis of 27 tropical foliage plants in a study conducted by Poole and Conover (1976). Although more research is needed in

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55 this area the information generated in this study should be a valuable guideline for growers and nurserymen in manag ing nutrient requirements of Adenium

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56 Data Experiment 1 3 Table 1 7 Effect of four fertilizer levels on growth, flowering and quality of Adenium obesum 1.25 L and 3.0 L pots after 20 weeks (July to December 2011). Pot Size (L) Canopy Height (cm) Canopy Width (cm) Leaf Length (cm) Leaf Width (cm) Caliper (cm) Top Dry Wt. (g) Root Dry Wt. (g) Average Flower Number z Visual Quality (1 5) y 1.25 23.5 34.4 8.8 2.1 2.4 29.7 12.8 8.4 4.0 3.0 27.5 45.2 8.6 2.0 3.1 60.4 19.0 19.2 4.4 Fertilizer (grams/L) 2 22.7 30.3 8.5 2.0 2.4 27.1 11.8 7.4 3.6 4 25.2 39.9 8.5 2.2 2.8 44.3 15.8 13.2 4.3 6 27.2 42.6 8.6 2.0 2.8 51.4 17.0 1 6.5 4.6 8 27.0 46.4 8.8 2.1 2.9 57.5 18.8 18.0 4.2 Significance x Pot Size ** ** ** ** ** ** ** ** ** Fertilizer ** ** NS NS ** ** ** ** ** Pot Size*Fertilizer NS NS NS NS NS ** NS ** ** z Average weekly flower coun t y Visual quality where 1 = unsalable, 3 = saleable, 5 = excellent quality. x NS, ** indicate non significant or significance at the P 0.01, respectively.

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57 Table 1 8 Effect of four fertilizer levels on growth, flowering and quality of Adenium obe sum 1.25 L and 3.0 L pots after 20 weeks (July to December 2011). Pot Size (L) Fertilizer (grams/L) Canopy Height (cm) Canopy Width (cm) Caliper (cm) Leaf Length (cm) Leaf Width (cm) Root Dry Wt. (g) 1.25 2 19.8 24.8 2.1 8.9 2.0 8.2 1.25 4 23.5 34.5 2.3 9.0 2.2 12.5 1.25 6 25.0 37.7 2.4 8.5 2.0 13.4 1.25 8 25.8 40.5 2.6 9.0 2.1 17.2 3.0 2 25.6 35.8 2.6 8.2 1.8 15.4 3.0 4 27.0 43.4 3.4 8.7 2.0 19.2 3.0 6 29.2 47.4 3.2 8.6 2.0 20.7 3.0 8 28.2 52.4 3.2 8.8 2.0 20.5 Significanc e z L** L** L** NS L* L** z Regression analysis where NS, L*, and L** indicates: Not significant, linear significance at the 0.05 level and linear significance at the 0.01 level, respectively. Figure 1 19 Interaction of fertilizer rate (2, 4, 6, or 8 grams/L) and pot size ( 1.25 L or 3.0 L ) on top dry weight of Adenium obesum grown for 20 weeks from July 25, 2011 to December 15, 2011. Interaction Significance at P=0.0053 0 10 20 30 40 50 60 70 80 2 4 6 8 Top Dry Weight (grams) Fertilizer Rate (grams/L) 1.25 L 3.0 L

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58 Figure 1 20 Interaction of fertilizer rate (2, 4, 6, or 8 grams/L) and pot size ( 1.25 L or 3.0 L ) on average weekly flower number of Adenium obesum 20 weeks from July 25, 2011 to December 15, 2011. Interaction Significance at P=0.0222 0 5 10 15 20 25 30 2 4 6 8 Average Weekly Flower Number Fertilizer Rate (grams/L) 1.25 L 3.0 L

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59 Figure 1 21 Interaction of fertilizer rate (2, 4, 6, o r 8 grams/L) and pot size ( 1.25 L or 3.0 L ) on visual plant quality of Adenium obesum from July 25, 2011 to December 15, 2011. Interaction Significance at P=0.0033 1 2 3 4 5 6 2 4 6 8 Visual Plant Quality Rating Fertilizer Rate (grams/L) 1.25 L 3.0 L

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60 Figure 1 22 Effect of 4 fertilizer levels on average w eekly flower number of Adenium obesum 1.25 L pots. Flower number was recorded for 10 weeks starting when the first open flower was observed. 0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0 40.0 Average Weekly Flower Number 2 grams/L 4 grams/L 6 grams/L 8 grams/L

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61 Figure 1 23 Effect of 4 fertilizer levels on average weekly flower number of Adeni um obesum 3.0 L pots. Flower number was recorded for 10 weeks starting when the first open flower was observed 0.0 10.0 20.0 30.0 40.0 50.0 60.0 70.0 80.0 Average Weekly Flowr Number 2 grams/L 4 grams/L 6 grams/L 8 grams/L

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62 Table 1 9 Effects of four fertilizer rates on the soluble salt concentration and pH balance of Adenium obesum grown in 1.25 L an d 3.0 L pots after 20 weeks. (July to December 2011). Fertilizer (mg/L) Soluble Salts ( S /cm) pH 2 392.7 7.2 4 743.3 7.1 6 1783 .0 6.6 8 1853.9 6.5 Pot Size (L) 1.25 829.9 7.0 3.0 1556.6 6.7 Significance z Fertilizer ** ** Pot Size ** Fertilizer*Pot Size z Regression analysis where L** indicates: Linear significance at the 0.01 level

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63 Table 1 10 Effect of four fertilizer levels on elemental values of Adenium obesum 1.25 L and 3.0 L pots after 20 weeks of growth (July to December 2011). Pot Size (L) N P K Mg Ca S Na Fe Mn B Cu Zn Percent (%) mg/L (ppm) 1.25 1.5 0 .20 2.2 0 .24 0 .34 0 .15 0 .11 31.0 22.9 21.9 9.3 18.9 3.0 1.5 0 .22 2.4 0 .25 0 .32 0 .16 0 .08 30.4 23.9 22.2 6.9 18.1 Fertilizer (grams/L) 2 1.5 0 .19 2.3 0 .25 0 .35 0 .15 0 .13 31.8 22.8 23.0 9.2 18.0 4 1.5 0 .20 2.2 0 .24 0 .34 0 .15 0 .10 20.2 24.0 21.2 8.3 19.0 6 1.5 0 .22 2.3 0 .24 0 .32 0 .15 0 .07 30.0 23.5 22.0 8.0 19.7 8 1.5 0 .21 2.4 0 .25 0 32 0 .16 0 .07 30.8 23.3 22.0 7.0 17.3 Significance z Pot Size NS NS NS NS NS NS NS NS Fertilizer NS NS NS NS NS NS NS NS NS NS NS Pot Size*Fertilizer NS NS NS NS NS NS NS NS NS NS NS z Regression ana lysis where NS, indicates non significance, and significance at the 0.05 level, respectively.

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64 Table 1 11 Effect of four fertilizer levels on elemental values of Adenium obesum 1.25 L and 3.0 L pots after 20 weeks of growth (July t o December 2011). Pot Size (L) N P K Mg Ca S Na Fe Mn B Cu Zn Percent (%) mg/L (ppm) 1.25 2.1 0.10 0.50 0.87 1.5 0.24 0.51 36.7 96.6 43.5 5.6 10.4 3.0 2.2 0.11 0.60 0.87 1.6 0.25 0.42 43.7 112.1 41.5 4.7 9.0 Fertilizer (grams/L) 2 1.9 0.09 0.65 0.88 1.5 0.23 0.67 35.7 86.0 42.0 5.0 10.2 4 2.1 0.10 0.45 0.84 1.5 0.24 0.44 38.8 97.0 39.0 5.3 9.8 6 2.2 0.11 0.53 0.88 1.6 0.24 0.41 38.0 117.3 44.7 4.8 9.5 8 2.4 0.12 0.58 0.87 1.6 0.25 0.35 48.2 117.0 44.3 5.5 9.3 Significance z Pot Size NS NS NS NS NS Fertilizer ** ** NS NS NS NS NS Pot Size*Fertilizer NS NS NS NS NS NS NS NS NS NS NS z Regression analysis where NS, *, ** indicates: Not sign ificant, significance at the 0.05 level, and significance at the 0.01 level, respectively.

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65 Table 1 12 Effect of four fertilizer levels on elemental values of Adenium obesum 1.25 L and 3.0 L pots after 20 weeks of growth (July to Dec ember 2011). Pot Size (L) N P K Mg Ca S Na Fe Mn B Cu Zn Percent (%) mg/L (ppm) 1.25 1.7 0.11 0.91 0.61 1.0 0.19 0.46 34.5 24.7 28.7 8.4 31.7 3.0 1.8 0.13 1.31 0.61 0.82 0.24 0.38 31.4 25.7 26.3 8.1 27.1 Fertilizer (grams/L) 2 1.5 0.10 1.08 0.78 1.06 0.20 0.54 36.8 23.2 28.7 8.3 34.5 4 1.6 0.11 0.89 0.58 0.94 0.20 0.41 34.8 26.3 26.8 8.2 32.3 6 1.8 0.13 1.12 0.53 0.82 0.21 0.36 28.8 24.3 26.3 8.2 25.7 8 2.1 0.14 1.34 0.54 0.82 0.25 0.36 31.3 26.8 28.0 8.3 25.0 Significance z Pot Size NS ** NS NS NS NS NS Fertilizer ** NS NS NS NS NS Pot Size*Fertilizer NS NS NS NS NS NS NS NS NS NS NS NS z Regression analysis where NS, *, and ** indicates: Not signif icant, significance at the 0.05 level, and significance at the 0.01 level, respectively.

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66 Table 1 13 Effect of four fertilizer levels on elemental values of Adenium obesum 1.25 L and 3.0 L pots after 20 weeks of growth (July to Dec ember 2011). Pot Size (L) N P K Mg Ca S Na Fe Mn B Cu Zn Percent (%) mg/L (ppm) 1.25 1.8 0.15 1.9 0.71 0.43 0.21 0.10 302.8 23.8 17.2 9.8 22.8 3.0 2.2 0.20 2.6 0.91 0.40 0.25 0.85 236.0 23.9 17.3 9.3 22.5 Fertilizer (grams/L) 2 1.5 0.13 1.6 0.70 0.46 0.18 1.08 353.0 29.2 17.0 10.7 24.0 4 1.8 0.16 2.3 0.78 0.34 0.22 0.86 202.0 18.0 15.0 7.8 21.7 6 2.2 0.20 2.3 0.77 0.41 0.24 0.85 241.7 20.5 17.7 9.3 21.8 8 2.5 0.21 2.8 0.98 0.45 0.27 0.89 280.8 27.7 19.3 10.2 23.7 Significance z Pot Size NS NS NS NS NS NS NS Fertilizer ** NS NS NS NS NS Pot Size*Fertilizer NS NS NS NS NS NS NS NS NS NS NS z Regression analysis where NS, *, and ** indicates: Not signi ficant, significance at the 0.05 level, and significance at the 0.01 level, respectively.

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67 Figure 1 24 Adenium obesu m 3.0 L and 1.25 L pots at experiment initiation with four fertilizer rat es The experimental design was a factorial analys is with two pot sizes and four fertilizer levels with 12 replications per treatment. Figure 1 25 Adenium obesum 1.25 L pots after 20 weeks (July to December 2011 ) of gro wth with four different rates of fertilizer 1.25 L 6g/L 4g/L 2g/L 8g/L

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68 Figure 1 26 Adenium obesum 3.0 L pots after 20 weeks of growth (July to December 2011 ) at f our different rates of fertilizer 3.0 L 6g/L 4g/L 2g/L 8g/L

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69 CHAPTER 3 PROPAGATION OF ADENIUM OBESUM UTILIZING VEGETATIVE TIP CUTTI NGS Introduction New varieties of Adenium obesum are becoming available for consumers and collectors from international breeders at a rapid rate. Adenium grown from seed propagation are highly variable, which aids in the increase in new plant varieties, but seedling variability is not des irable for scientific experimental work. Adenium plants obtained via vegetative propagation would be most desirable for experimental purposes because test plants would be genetically identical. A review of the literature revealed general guidelines for Adenium propagation but there was little experimental based data regarding vegetative cutting propagation. Dimmitt et al. (2009) stated that the optimum rooting medium temperature for Adenium is 27 to 32 o C (80 90F) however no d ata was presented. Accordi ng to Brown (2012) Adenium plants can be started from cuttings, seeds or by grafting. Cuttings, 6 inches or longer, could be taken from the tip of the stems, allowed to callus over then dipped into a fungicide before placement in pots, but no specific data were given. Treating cuttings with auxin can increase rooting percentage, hasten root formation, and incr ease uniformity of rooting (Davis et al., 1988). The naturally occurring auxin, indole 3 acetic acid (IAA), is found in plants and its involvement in nearly every aspect of plant growth and d evelopment has been documented (Hartmann et. al 2002 Taiz and Zeiger, 2006, Raven et. al. 2005 ). Plant processes regulated by IAA are important to plant propagation and include: induction of cell division, apical dominance, stem elongation and induction of rooting (Srivastava, 2002). Synthetic

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70 forms of auxin are com mercially available in the form of indole 3 butyric acid (IBA) and naphthalene acetic acid (NAA). Preference for these synthetic compounds compared to IAA, is indicated by the high number of rooting products containing IBA, NAA, or in combination (Blazich, 1988). Several studies on effects of rooting hormones during propagation of other genera within the family Apocynaceae have been published. Hartmann et al. (2002) recommended propagating Mandevilla splendens cultivar Alice DuPont stem cuttings by dippin g them in 2500 mg/L IBA and rooting them in summer. A recent propagation study (Cerveny, 2006) with Mandevilla splendens generally not useful during the warm season (August/September). However, application of rooti or KIBA (a water soluble rooting hormone containing indole 3 butyric acid and potassium salt) at 1500 mg/L during the cool season (November /December) produced bett er rooting quality values when compared to the control. KIBA at 6000 mg/L was consistent in improving rooting quality throughout the entire study when compared to other treatments. Allamanda schottii Pohl were reported to be propagated easily by semi hardwood cuttings in summer and fall with up to 2000 mg/L IBA applied to the base of the cuttings (Hartmann et al., 2002). Cerveny (2006) reported that KIBA at 3000 mg/L was the most consistent treatment for increased visual rooting quality, higher number of primary roots, increased total cutting dry weight, and highest root:s hoot ratio of Allamanda cuttings. Propagation of Nerium oleander L. has been successful from cuttings taken from hardwood or softwood during the summer and treated with quick dip applications of 3000 mg/L IBA (McCulla, 1973; Hartmann et al., 2002). Cerven y (2006) found that the

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71 cutting root:shoot ratio of Nerium oleander was enhanced with at 1500 mg/L. Propagation experiments conducted on Vinca minor L. found that rooting percentages a nd root numbers were increased with application of IBA+NAA at 1000 + 500 mg/L but higher concentrations (3000 mg/L+1500 mg/L) tended to reduce rooting percentages (Landon and Banko, 2005) Plumeria o C for 10 minutes) + IBA (8000 mg/L) or treated with IBA (8000 mg/L) alone had a significantly higher rooting p ercentage and more roots compared with hot water alone or control treatments (Hata et al., 1994) Criley (1998) recommended treatment of the base of Plumeria sp. cuttings with 3000 mg/L IBA Micropropagation (tissue culture) can produce true to type explants, with rapid multiplication in vitro and with lower space requirements and production costs. Experiments in micropropagation of Adenium obesum showed that the addition of 0.5 (Xiaomei et al., 2003) A recent report by (Kanchanapoom et al., 2010) grew Adenium obesum explants in vitro with success using d ifferent combinati ons of NAA (0 to 5.4 M) and benzyladenine (BA) (0 to 22.2 M). Another study by (Liu et al., 2004) found that using NAA (0.2 to 0.4 mg/L) + BA (1 to 2mg/L) induced callus in Ad enium obesum cultures Although stem cuttings were not utilized in these studies, these results also point to auxins having a significantly positive effect on rooting Adenium obesum cuttings To our knowledge, micropropagation of Adenium is not a widely es tablished commercial technique at this time. Based on the literature the following experiments

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72 were conducted to develop information on vegetative propagation of Adenium obesum using stem tip cuttings. Materials and Methods The first four rooting experim ents to test the effects of commercial rooting compounds were initiated May 4, August 1, September 2 and September 27, 2011. During these months, temperatures of the propagation media were between 32 and 35 C (90 and 95 F). In order to continue the work du ring winter 2012, bottom heat was supplied by an electric heating pad ( PM 9A Mat 55.8 cm x 152.4 cm; Pro Grow San Marcos, Ca 92069 ) placed under the propagation bed and covered by 4 mil black plastic. The pad temperature was controlled by a thermostat (Pro Grow GC 1 Gro Control Thermostat; San Marcos, Ca 92069 ) to main tain the soil temperature at 25 to 32 C (77 to 80 F). Seven propagation rooting experiments were initiated February 13, March 26 (3 experiments), March 29 (2 experiments) and April 3, 2012. T he following procedures were standard in each of the eleven propagation experiments: Terminal stem cuttings (tip cuttings) 8 to 10 cm in length were taken from sufficiently mature new growth ( Figure 2 2 ) Lower leaves and any visible flower buds were remov ed. Cuttings were held in containers of tap water to keep them turgid before hormone treatments and placement into rooting trays. In all eleven experiments, cuttings were removed fr om the containers of water, placed onto terry cloth towels and blotted dry. Hormodin 1, Hormodin 2, and Hormodin 3 rooting powders ( E. C. Geiger, Inc. Harleysville, PA 19438 liquid rooting Inc., Clackamas, Oregon 97015) containing IBA and NAA were tested. Concentrations and active ingredients of auxin hormones used in these studies are listed in Table 2 1 The base of each cutting was dipped approximately 1 cm

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73 into the rooting powder and cuttings were stuck into preformed holes in the pre moistened rooting medium or they liquid solution for 5 seconds at a 1 cm depth and then stuck. In all experiments, treated cu ttings were stuck into 50 cell trays (25.4 cm x 50.8 cm) filled with pre moistened Fafard 2 mix (65% Canadian sphagnum peat, 20% perlite, and 15% vermiculite by volume; Conrad Fafard Inc, Agawam, MA 01001). In all experiments cuttings were placed in a completely randomized design within the propagation tray with each cutting considered a single replication. Propagation trays ( Figur e 2 3 ) were placed under overhead mist irrigat ing six seconds every ten minutes from 9:00 am to 5:00 pm in a greenhouse covered with a clear double polyethylene roof that pr ovided a photosynthetically active radiation (PAR) light intensity of 1480 m 2 s 1 A single layer of 30% shade cloth was suspended over the mist bench which resulted in a canopy level light intensity of 740 m 2 s 1 In all eleven experiments cuttings were removed from the mist bench after 4 weeks and rooting data was c ollected. Data included, number of roots per cutting, length of the longest root and percent rooting. Rooting data were analyzed using ANOVA procedures of the SAS program (SAS Institute Inc., Cary, NC), and mean ultiple range test at 5% level.

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74 Experiment 1 On May 4, 2011, one hundred uniform tip cuttings of Adenium obesum were taken from stock plants maintained in 1.25 L (15.2 cm diameter) pots in a greenhouse at MREC Apopka covered with double polye thylene with a maximum PAR light intensity of 1017 m 2 s 1 Cuttings were div ided into five treatments: 1000 mg/L IBA (Hormodin 1), 3000 mg/L IBA (Hormodin 2), 8000 mg/L IBA (Hormodin 1:9) and water con trol (no hormone). Cuttings were placed under mist from May 4, 2011 until June 1, 2011 at which time cuttings were removed from mist and final data was taken. Results After four weeks there were no differences in root number between treatments (Table 2 2 ). 1:9 and the water control had significantly longer roots while those treated with Hormodin 2 and Hormodin 3 had the shortest. The rooting percentage was 100% for cuttings treated with Hormodin Grow 1:9 and the water control. Experiment 2. On August 1, 2011, one hundred fifty uniform tip cuttings of Adenium were taken from stock plants maintained in 3.0 L (20.3 cm diameter) pots under full sun conditions (1831 m 2 s 1 ). Cutti ngs were divided into five treatments: 1000 mg/L IBA (Hormodin 1), 3000 mg/L IBA (Hormodin 2), 8000 mg/L IBA (Hormodin 3), 1000 1:9 ) and water control (no hormone). The cuttings were under mist August 1 to August 29 2011 at which time cuttings were removed from mist and final data was taken. Results After four weeks under mist, cuttings treated with Hormodin 2 and Hormodin 3 had the highest root number compared to Hormodin

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75 (1:9) (Table 2 3 ). R oot number of the water control cuttings was not statistically different from Hormodin 1, Hormodin 2, or Hormodin (1:9). Root length was (1:9), Hormodin 1 and the water control treatments, and shorter root length was seen in Hormodin 2 and even shorter with Hormodin 3 treatment. The rooting percentage of the treatments was the greatest with Hormodin 1, (1:9) and water control and decreased with Hormodin 2 and Hormodin 3. Hormodin 1 and Dip (1:9) and the water control were statistically the same, while the results of Hormodin 2 and Hormodin 3 showed an increase in root number, shorter root lengths but lower rooting percentage. Experiment 3. On September 2, 2011, fifty uniform ti p cuttings of Adenium were taken from stock plants maintained in 3.0 L (20.3 cm diameter) pots in a greenhouse covered with a clear double polyethylene roo f with a PAR light intensity of 1295 m 2 s 1 Cuttings were divided into five treatments: 1000 mg/L IBA (Hormodin 1), 3000 mg/L IBA (Hormodin 2), 8000 mg/L IBA (Hormodin 3), 1000 (1:9) and water control (no hormone). Cuttings were under mist from S eptember 2 to September 30, 2011 at which time cuttings were removed from mist and final data was taken. Results Hormodin 3 treatment resulted in a significantly larger number of roots compared to all other treatments (Table 2 4 ). Root number for the Hor modin 3 treated cuttings more than doubled that recorded for all the other treatments. There was no significant difference in root length between treatments and 100% of cuttings rooted.

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76 Experiment 4. On September 27, 2011 one hundred uniform tip cuttin gs of Adenium cuttings were taken from stock plants maintained in 3.0 L (20.3 cm diameter) pots in a greenhouse covered with double polyethylene which pr ovided a PAR light intensity of 1295 m 2 s 1 Cuttings were divided into five treatment s: 1000 mg/L IBA (Hormodin 1), 3000 mg/L IBA (Hormodin 2), 8000 mg/L IBA (Hormodin 3), 1000 1:9) and water control (no hormone). The cuttings were under mist from September 27 to October 25, 2011 at which time cuttin gs were removed from mist and final data was taken. Results Root number was significantly greater for cuttings treated with Hormodin 3 (Table 2 5 ). There was no significant difference in root length regardless of treatment. Rooting percentage was 100% fo 1:9 treatments and 95% for all other treatments. Experiment 5. On February 13, 2012, fifty uniform tip cuttings of Adenium obesum were taken from stock plants maintained in 3.0 L (20.3 cm diameter) pots in a gre enhouse covered with double polyethylene that pr ovided a PAR light intensity of 1202 m 2 s 1 Cuttings were divided into five treatments:1000 mg/L IBA (Hormodin 1), 3000 mg/L IBA (Hormodin 2), 8000 mg/L IBA (Hormodin 3), 1000 1:9) and water control (no hormone). Cuttings were under mist from Feb ruary 13 to March 13 2012 at which time cuttings were removed from mist and final data was taken.

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77 Results Treatments Hormodin 2 and Hormodin 3 resulted in a significant ly higher root number (Table 2 6 ). There was no significant difference in root lengt h regardless of treatment and rooting percentage was 100% for all except Hormodin 1. Experiment 6. On March 26, 2012, fifty uniform tip cuttings of Adenium obesum were taken from stock plants maintained in 3.0 L (20.3 cm diameter) pots in a greenhouse covered with double polyethylene that pr ovided a PAR light intensity of 1202 m 2 s 1 Cuttings were divided into five treatments: 1000 mg/L IBA (Hormodin 1), 3000 mg/L IBA (Hormodin 2), 8000 mg/L IBA (Hormodin 3), 1000 mg/L IBA 1:9) and water control (no hormone). The cuttings were under mist from March 26 to April 23, 2012 at which time cuttings were removed from mist and final data was taken. Results Hormodin 2 and Hormodin 3 treated cuttings ave raged significantly more roots that any other treat ments (Table 2 7 ). Root length was statistically the same and rooting was 100% for all treatments. Experiment 7. On March 26, 2012, fifty uniform tip cuttings of Adenium obesum taken from stock plants maintained in 3.0 L (20.3 cm diameter) pots in a greenhouse covered with double polyethylene that pr ovided a PAR light intensity of 1202 m 2 s 1 Cuttings were divided into five treatments: 1000 mg/L IBA + 500 1:9 ( ), 2000 mg/L IBA ), 4000 mg/L 2:3 (40% active ingredient of Grow 4:1 (80% active ingredient

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78 ) and a water control (no hormone). The cuttings were under mist from March 26 to April 23, 2012 at which time cuttings were removed from mist and final data was taken. Results Root number increased in a significant l inear manner as IBA + NAA rooting hormone co ncentration increased (Table 2 8 at 4:1 rate had almost 10 times the root number compared to the water contr ol cuttings. The concentration (2:3) had the longest root lengths which almost doubled the lengths of the next best treatment. Experiment 8. On March 26, 2012, fifty uniform tip cuttings of Adenium obesum taken from stock plants maintained in 3.0 L (20.3 cm diameter) pots in a greenhouse covered with dou ble polyethylene that provided a maximum PAR light intensity of 1202 m 2 s 1 Cuttings were divided into five treatm ents: 1000mg/L IBA + 500 mg/L ), 2000 mg/L IBA + 1000 ), 4000 mg/L Gr ow 4:1 (80% active ingredient of ) and a water control (no hormone). The cuttings were under mist from March 26 to April 23, 2012 at which time cuttings were removed from mist and final data was taken

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79 Results (4:1) produced the highest root number and root length, and als o had 100% rooting (Table 2 9 ). at the 2:3 rate produced double the number of roots compared to the control as well as the low rate (1:9). Experiment 9. On March 29, 2012, fifty uniform tip cuttings of Adenium obesum were taken from stock plants maintained in 3.0 L (20.3 cm diameter) pots in a greenhouse covered in a clear double polyethylene that p rovided a PAR light intensity of 12 0 2 m 2 s 1 Cuttings were divided into five treatments: 1000 mg/L IBA (Hormodin 1), 3000 mg/L IBA (Hormodin 2), 8000 mg/L IBA (Hormodin 3), 1000 1:9) and water control (no hormone). Th e cuttings were under mist from March 29 to April 26, 2012 at which time cuttings were removed from mist and final data was taken. Results Cuttings treated with Hormodin 2 or Hormodin 3 produced significantly more roots and the longest roots in this tes t compared to the control and the lowest Hormodin rate (Table 2 10 ). Percent rooting was greatest for Hormodin 2 and the water control, while the second best was Hormodin 3. Experiment 10. On March 29, 2012, fifty uniform tip cuttings of Adenium obesu m taken from new growth of stock plants maintained in 3.0 L (20.3 cm diameter) pots respectively in a clear double polyethylene covered greenhouse that pr ovided a PAR light intensity of 1202 m 2 s 1 Cuttings were divided into five tre atments: 1000 mg/L IBA (Hormodin 1), 3000 mg/L IBA (Hormodin 2), 8000 mg/L IBA (Hormodin 3), 1000 1:9) and water control (no hormone). The

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80 cuttings were under mist from March 29 to April 26, 2012 at which time cuttin gs were removed from mist and final data was taken. Results Hormodin 3 treatment resulted in a significantly higher root number and root length although the root length was not significantly different from Hormodin 2 and (1:9) (Table 2 11 ). Root number was more than triple the control and five times that of Hormodin 1. Percent rooting was also the greatest with Hormodin 3 as 1:9 and the water control. Experiment 11. On April 3, 2012, one hundred uniform tip cuttings of Adenium from stock plants maintained in 3.0 L (20.3 cm diameter) pots in a greenhouse covered with clear double polyethylene that p rovided a PAR light intensity of 1295 m 2 s 1 Grow ), 4000 mg/L IBA + 2000 mg/L NA A ), 8000 mg/L IBA + 4000 mg/L ) and a water control (no hormone). The cuttings were under mist from April 3 to May 1, 2012 at which time cuttings were removed from mist and final data was taken. Results Root number and root length increased in a significant linear manner as conc entrations increased (Table 2 12 ). Root number for the highest concentration was ten times th at of the control, and four times the concentrations. Percent rooting was rates.

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81 Discussion Data from 100 control cuttings of Adenium obesum ate experiments showed a 100% rooting success. Across the same seven experiments, when rooting compound treatments were applied, 500 Adenium obesum cuttings rooted at a 97% success rate. In the four separate experiments with Adenium obesum the 60 untreated control cuttings had a mean rooting percent of 85%. The average rooting percentage of 300 Adenium obesum individual rooting compound experiments reg ardless of treatment was 87.2%. Overall, Adenium obesum Adenium obesum The time frames for the rooting experiments included late summer, early fall, late winter and early spring. Joiner et. al. (1981) stated that time of year can be one factor influencing efficacy of hormone response in plant propagation. Combined results show 85 % to 100% overall rooting percentage indicating that ti me of year was not a factor in rooting Adenium obesum Mandevilla cuttings in the fall (August/September) were ineffective. Adenium should root well when pro vided proper conditions. In this work conditi ons included a mist setting (6 seconds every 10 minutes) from 9:00 am to 5:00 pm, a propagation bench w ith a PAR m 2 s 1 well aerated commercial propagation mix and bottom heat in the winter to provide a minimum soil temperature of 25 to 32C. Data showed that Adenium obesum Adenium obesum produced the most roots at the highest IBA levels teste d which were treatments at 8000 mg/L IBA (Hormodin

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82 at 4:1). Plumeria in which we found reports of cutting s treated successfully with such a high rate of IBA. In that study, Plumeria cuttings treated with 8000 mg/L IBA had a significantly higher rooting percentage and more roots compared to the water controls (Hata et al., 1994). In six experiments with Ade nium obesum Hormodin (1:9) the highest root number was from Hormodin 3 treatments. In three of the six experiments Hormodin 2 was equal to Hormodin 3 and in one experiment the water control was equal to both. Root length was not affected by Hormodin 3 or Hormodin 2 treatment, except in one experiment (1:9) and water produced significantly longer roots. Typical rooting results are shown in Figure 2 4 Two experim ents on Adenium obesum rates (4:1), produced the most roots, the longest roots and 100% rooting. In the first experiment (4:1) treatment more than doubled root (3:2) rate. In the (4:1) produced 25% more roots (2:3). Typical rooting results are shown in Figure 2 5 For Adeni um obesum (4:1) both root Grow (2:3). Both treatments had more than double the number of control roots. Typical rooting results a re shown in Figure 2 6

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83 It is apparent from these experiments that rooting cuttings of Adenium obesum benefits significantly by the usage of high IBA (Hormodin 3) or 4:1). Our results are similar to studie s with Mandevilla splendens eatment of cuttings at 6000 mg/L IBA gave the most consistent rooting quality (Cerveny, 2006). Most reports for members of the Apocynaceae family recommend lower rooting hormone rates including Mandevi lla x Alice DuPont at 2500 mg/L IBA (Har t mann et al. 2002); Allamanda schottii Pohl at 2000 mg/L IBA (Hartmann et al. 2002); Nerium oleander L at 3000 mg/L IBA (McCulla, 1973) and Plumeria sp. at 3000 mg/L IBA (Criley 1998, 2005). Our results with hig h indicate more research in this area is warranted.

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84 Table 2 1 A list of rooting compounds and the active ingredients used for cutting propagation experiments with Adenium obesum Root ing Compound IBA (mg/L) NAA (mg/L) Hormone form Hormodin 1 1000 0 powder Hormodin 2 3000 0 powder Hormodin 3 8000 0 powder (1:9) z 1000 500 liquid (1:4) 2000 1000 liquid (2:3) 4000 2000 liquid (4:1) 8000 4000 liquid Water (control) 0 0 z were to 9 parts water; resulting to 10% active ingredient), 1 to 4 to 3 parts water; resulting to to 1 part water; resulting to 80% active ingredient). Table 2 2 Effe cts of four rooting compounds on root number, root length and rooting percentage of Adenium obesum our weeks under mist (5/4/2011 to 6/1/2011). Rooting Compound Root Number z Root Length (cm) Rooting % Hormodin 1 15.3 a 6.7 b 100 Hormodin 2 19.3 a 3.8 c 70 Hormodin 3 23.5 a 2.6 c 95 (1:9) 17.6 a 8.1 a 100 Water (control) 21.8 a y 7.2 ab 100 z 20 replications per treatment. y Means within the same column followed by the same letters are not signific antly different (P 0.05) as Table 2 3 Effects of four rooting compounds on root number, root length and rooting percentage of Adenium obesum r 4 weeks under mist (8/1/2011 to 8/29/2011). Rooting Compound Root Number z Root Length (cm) Rooting % Hormodin 1 15.5 b 6.8 a 100 Hormodin 2 24.6 a 4.8 b 80 Hormodin 3 24.4 a 3.0 c 93 (1:9) 16.9 b 7.8 a 100 Water (control) 20.7 ab y 7.3 a 100 z 30 replications per treatment y Means within the same column followed by the same letters are not significantly different (P 0.05) as

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85 Table 2 4 Effects of four rooting hormones on root number, root length and rooting percentage of Adenium obesum r 4 weeks under mist (9/2/2011 to 9/30/2011). Rooting Compound Root Number z Root Length (cm) Rooting % Hormodin 1 6.5 b 6.8 a 100 Hormodin 2 8.4 b 6.3 a 100 Hormodin 3 21.0 a 6.6 a 100 (1:9) 9.5 b 5.3 a 100 Water (control) 6.6 b y 6.9 a 100 z 10 replications per treatment. y Means within the same column followed by the same letters are not significantly different (P 0.05) as Table 2 5 Effects of four rooting hormones on root number, root length and rooting percentage of Adenium obesum r 4 weeks under mist (9/27/2011 to 10/25/2011). Rooting Compound Root Number z Root Length (cm) Rooting % Hormodin 1 7.1 b 1.4 a 95 Hormodin 2 10.7 b 1.9 a 95 Hormodin 3 17.6 a 1.4 a 95 (1:9) 9.1 b 1.5 a 100 Water (control) 8.5 b y 1.8 a 100 z 20 replications per treatment. y Me ans within the same column followed by the same letters are not significantly different (P 0.05) as Table 2 6 Effects of four rooting compounds on root number, root length and rooting percentage of Adenium obesum 4 weeks under mist (2/13/2012 to 3/13/2012). Rooting Compound Root Number z Root Length (cm) Rooting % Hormodin 1 5.3 b 2.5 a 90 Hormodin 2 12.8 ab 3.2 a 100 Hormodin 3 19.8 a 3.6 a 100 (1:9) 10.2 b 3.7 a 100 Water (control) 7.3 b y 2.6 a 100 z 10 replications per treatment. y Mea ns within the same column followed by the same letters are not significantly different (P 0.05) as

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86 Table 2 7 Effects of four rooting compound on root number, root length, and rooting percentage of Adenium. obesum r 4 weeks under mist (3/26/2012 to 4/23/2012). Rooting Compoun d Root Number z Root Length(cm) %Rooting Hormodin 1 10.2b 2.6a 100 Hormodin 2 23.8a 2.8a 100 Hormodin 3 28.3a 4.1a 100 (1:9) 10.8b 3.4a 100 Water (control) 12.3b y 2.5a 100 z 10 replications per treatment. y Means within the sam e column followed by the same letters are not significantly different (P 0.05) as Table 2 8 Effects of four rooting compounds on root number, root length, and rooting percentage of Adenium. obesum 4 weeks under mist (3/26/2012 to 4/23/2012). Rooting Compoun d Root Number z Root Length (cm) %Rooting (1:9) 7.7 1.5 90 (1:4) 6.6 2.4 100 (2:3) 25.1 4.6 90 (4:1) 33.6 4.5 100 Water (control) 3.5 0.6 70 Significance y **L **L*Q -z 10 replications per treatment. y Regression analysis where **, indicates: Significance at the 0.01 level and significance at the 0.05 level, respectively. L = Linear Q = Quadratic. Table 2 9. Effects of four rooting hormones on root number, root length, and rooting percentage of Adenium obesum 4 weeks under mist (3/26/2012 to 4/23/2012). Rooting Compound Root Number z Root Length (cm) %Rooting (1:9) 13.5 3.4 100 (1:4) 12.9 2.9 100 ow (2:3) 28.5 4.9 100 (4:1) 34.7 5.6 100 Water (control) 12.3 3.1 100 Significance y **L*C **L -z 10 replications per treatment. y Regression analysis where **, indicates: Significance at the 0.01 level and significance at the 0.05 level, respectively. L = Linear, C = Cubic.

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87 Table 2 10 Effects of four rooting compounds on root number, root length, and rooting percentage of Adenium obesum 4 weeks under mist (3/29/2012 to 4/26/2012). Rooting Compound Root N umber z Root Length (cm) %Rooting Hormodin 1 1.2c 0.6b 40 Hormodin 2 10.5ab 2.9a 100 Hormodin 3 14.1a 3.0a 90 (1:9) 4.8bc 1.0b 70 Water (control) 4.0bc y 1.0b 100 z 10 replications per treatment. y Means withi n the same column followed by the same letters are not significantly different (P 0.05) as Table 2 11 Effects of four rooting compounds on root number, root length, and rooting percentage of Adenium obesum 4 weeks under mist (3/29/2012 to 4/26/2012). Rooting Compound Root Number z Root Length (cm) %Rooting Hormodin 1 7.9b 1.6b 90 Hormodin 2 13.4b 2.9ab 90 Hormodin 3 40.8a 4.2a 100 (1:9) 15.9b 3.0ab 100 Water (control) 11.5b y 1.6b 100 z 10 replications per treatment. y Means within the same column followed by the same letters are not significantly different (P 0.05) as Table 2 12 Effects of four rates of IBA +NAA on root number, root length, and rooting percentage of Adenium obesum r 4 weeks under mist (4/3/2012 to 5/1/2012). Rooting Compound Root Number z Root Length (cm) %Rooting (1:9) 5.2 1.4 75 (1:4) 5.6 1.5 85 (2:3) 9.4 1.9 100 (4:1) 24.7 3.3 100 Water (control) 2.2 y 0.9 70 Significance y **L **L -z 20 replicat ions per treatment. y Means within the same column followed by the same letters are not significantly different (P 0.05) as

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88 Figure 2 1. Light levels in the greenhouse and under mist from May 2011 to May 2012. 0 1000 2000 3000 4000 5000 6000 7000 8000 9000 5/10/11 6/10/11 7/10/11 8/10/11 9/10/11 10/10/11 11/10/11 12/10/11 1/10/12 2/10/12 3/10/12 4/10/12 5/10/12 Light levels uE m 2s 1 Experimental Time Frame Greenhouse Mist Area

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89 Figure 2 2 Terminal stem cuttings (tip cuttings) 8 to 10 cm in length were taken from sufficiently mature n ew growth. Lower leaves and any visible flower buds were removed. Figure 2 3 Adenium cuttings in the mist area that irrigated six seconds every ten minutes from 9:00 am to 5:00 pm in the greenhouse under 30% shade cov er and a light intensity of 740 l m 2 s 1

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90 A B C D E Figure 2 4 The effect of rooting compounds on rooting of Adenium obesum after 4 weeks under mist: A) water control B) Hormodin 1 C) Hormodin 2 D) Hormodin 3 E) Grow (1:9)

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91 A B C D E F igure 2 5 The effect of rooting compounds on the rooting of Adenium obesum after 4 weeks under mist: A) water control, B) 1000mg/L IBA + 500 mg/L NAA ), C) 2000 mg/L IBA + ), D) 2:3 (40% active ingredient of ), E) 4:1 (80% )

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92 A B C D E Figure 2 6 The effect of rooting compounds on the rooting of Adenium obesum 1000mg/L IBA + 500 mg/L ), C) 2000 mg/L 1:4 Grow ), D) 2:3 (40% active ), E) )

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93 CHAPTER 4 CONCLUSION Field and green house growth experiments conducted in 2010 through 2012 studied effect of light and nutritional levels on the growth, flowering and quality of containerized Adenium obesum vegetatively propagated liner plants in 1.25 L pots were top dressed with slow release fertilizer at 2, 4 or 6 grams of fertilizer per liter of soil volume and grown for 16 weeks (April to August) in full sun 30 % or 50% shade. Best growth, flowering and quality for both cultivars were plants fertilized with the 6 grams/L fertilizer rate and grown under 30% shade. Increasing fertilizer rate and decreasing shade levels improved flower number and visual quality of Adenium obesum length and leaf wi dth of Adenium obesum increased. Canopy height and canopy width significantly increased as fertilizer levels increased ( Table 1 3 ) Flower number and visual plant quality was greatest with plants grown under 30 % shade at the highest fertilizer level. O ptimal flowering of Adenium obesum ved at PAR light levels between 740 to 1480 m 2 s 1 which corresponded to the 30% shade level In a second field experiment, Adenium obesum plants were grown for 20 weeks (July to December 2011 ). C anopy height and width increased significantly in response to higher fertilizer and shade levels L eaf length and width was not significantly affected by fertilizer level or shade level in this test Weekly flower counts increased significantly with higher fertilizer rates but decreased as shade level increased. The highest average weekly flow er counts observed were 4.5 and 4.9 flowers per plant at 6 grams fertilizer rate per liter of soil volume at full sun and 30%

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94 shade respectively Top dry weight of plants increased significantly at higher fertilizer and shade levels. Root dry weight was gr eatest under the full sun and at the highest fertilizer treatment Root dry weight increased as fertilizer rate increased regardless of light level Root dry weight of full sun grown plants was almost doubled that of plants at 50% shade level. Top dry weig ht s exceeded root dry weight s in all treatments The smallest difference in shoot to root ratio was 1.4 at the 2 grams/L fertilizer rate at either 0 % or 30% shade while the largest shoot to root ratio was 3.8 recorded at 6 grams/L and 50% shade. A greenho use study wa s conducted for 20 weeks (July to December 2011 ) with Adenium obesum 1.25 L and 3.0 L pots with four fertilizer rates (2, 4, 6, or 8 grams/L) The greenhouse study showed the optimal fertilizer rate was 6 g rams per liter of soil. Th is treatment produced the largest, most floriferous and best quality plants after 20 weeks Plants in 3.0 L pots produced significantly higher top and root dry weights than those in 1.25 L pots. Top dry weight and flower number of plants grown in 3.0 L pots more than doubled the top dry weight and flower number of plants grown in 1.25 L pots. Root dry weight of plants grown in 3.0 L pots was 33% greater than plants in 1.25 L pots. Analysis of nutrient content of leaves, stems, roots and flowers showed t hat Adenium seems to require similar amounts of N, P, K and Ca as other tropical foliage plants. Based on our data good quality Adenium plants were produced at a total soluble salts reading in the range of 1000 to 18 00 S/cm with a soil pH between 6.5 to 7.2

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95 Propagation tests using Adenium obesum cuttings showed best rooting occurred in cuttings treated with 8000 mg/L IBA or a combination of 8000 mg/L IBA plus 4000 mg/L NAA.

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96 AP PENDIX EXTRA DATA TABLES AN D FIGURES Table A 1 Effect of shade and fertilizer level on the growth of Adenium obesum August 2010). Fertilizer (g/L) Shade % Canopy Height (cm) Canopy Width (cm) Leaf Length (cm) Leaf Width (cm) 2 0 16.2 13.1 5.2 1.8 2 30 20.1 16.4 5.8 2.0 2 50 21.9 17.8 5.5 2.5 4 0 21.4 17.8 5.2 1.8 4 30 24.6 21.7 5.2 2.0 4 50 26.9 25.0 5.7 2.3 6 0 23.8 23.0 5.4 1.8 6 30 27.0 24.8 5.9 2.0 6 50 29.3 30.0 5.8 2.2 Significance NS NS NS NS z Average weekly flower count. y Visual quality where 1 = unsalable, 3 = saleable, 5 = excellent quality. x Regression analysis where NS, **L, *L, **Q indicate: not significant, linear significance at the 0.01 level, and linear signi ficance at the 0.05 level, and quadratic significance at the 0.01 level, respectively.

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97 Table A 2 Effect of shade and fertilizer level on growth and flowering of Adenium obesum August 2010). Fertilizer (g/L) Shade % Canopy Height (cm) Canopy Width (cm) Leaf Length (cm) Leaf Width (cm) 2 0 16.3 18.1 7.1 1.6 2 30 19.5 21.3 7.8 1.8 2 50 25.3 30.0 7.4 1.8 4 0 21.2 22.4 7.0 1.6 4 30 23.0 28.5 7.7 1.8 4 50 25.1 34.6 7.7 1.9 6 0 23.4 27.9 7.2 1.5 6 30 23.8 32.5 7.7 1 .8 6 50 25.2 39.2 7.9 1.8 Significance x NS NS NS NS z Average weekly flower count. y Visual quality where 1 = unsalable, 3 = saleable, 5 = excellent quality. x Regression analysis where NS, **L, **Q, *Q indicates: Not significant, linear significa nce at the 0.01 level, quadratic significance at the 0.01 level, and quadratic significance at the 0.05 level, respectively.

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98 Table A 3 Effect of fertilizer and shade level on growth, flowering and quality of Adenium obesum (July December 2011). Shade % Fertilizer (g/L) Canopy Height (cm) Canopy Width (cm) Leaf Length (cm) Leaf Width (cm) Caliper (cm) Top Dry Wt (g) Root Dry Wt (g) 0 2 14.2 16.2 7.1 2.0 2.0 7.9 5.7 0 4 19.0 19.4 7.5 1.8 1.9 13.1 7.9 0 6 21.0 21. 0 7.5 1.8 2.3 23.3 11.9 30 2 17.2 17.0 7.0 1.6 2.0 8.8 6.4 30 4 22.5 23.8 7.7 1.9 2.2 18.9 7.9 30 6 22.8 22.8 7.8 1.9 2.2 23.9 9.8 50 2 22.2 20.0 8.0 1.8 1.9 11.7 4.4 50 4 25.2 26.2 7.7 1.8 2.1 18.2 6.0 50 6 25.7 29.8 7.9 1.8 2.2 23 .7 6.3 Significance x **L *L NS NS NS NS *L z Average weekly flower count. y Visual quality where 1 = unsalable, 3 = saleable, 5 = excellent quality. x Regression analysis where NS, **L, *L indicates: Not significant, linear significance at the 0 .001 level, and linear significance at the 0.05 level, respectively.

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99 Table A 4 Effect of four fertilizer levels on growth, flowering and quality of Adenium obesum after 20 weeks (July December 2011). Fertilizer (g /L ) P ot Size Canopy Height (cm) Canopy Width (cm) Calip er (cm) Leaf Length (cm) Leaf Width (cm) Top Dry Wt. (g) Root Dry Wt (g) 2 6 19.8 24.8 2.1 8.9 2.1 15.5 8.2 2 8 25.6 35.8 2.6 8.2 1.9 38.7 15.4 4 6 23.5 34.5 2.3 9.0 2.3 28.1 12.5 4 8 27.1 43.4 3.4 8.7 2.0 60.6 19.3 6 6 25.1 37.7 2.4 8.5 2.0 35.3 13.4 6 8 29.3 47.5 3.2 8.6 2.0 67.4 20.7 8 6 25.8 40.5 2.7 9.0 2.1 39.8 17.3 8 8 28.3 52.4 3.2 8.8 2.1 75.2 20.5 Significance z **L **L *L NS NS **L **L z Regression analysis where NS, *L, and**L indicates: Not significant, linear significance at the 0.05 level and linear signifi cance at the 0.001 level, respectively.

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100 Table A 5 Effect of four fertilizer levels on mineral nutrient concentration s of Adenium obesum inch pots after 20 weeks (July December 2011). Fertilizer (g/L) Pot Size N P K Mg Ca S Na Fe Mn B Cu Zn 2 1.25 1.4 0.19 2.20 0.24 0.36 0.15 0.17 31.7 18.3 20.7 9.7 20.0 2 3.0 1.5 0.20 2.40 0.25 0.35 0.16 0.10 32.0 27.3 25.3 8.7 16.0 4 1.25 1.6 0.19 2.09 0.24 0.36 0.15 0.12 32.0 24.3 22.7 10.0 20.0 4 3.0 1.5 0.21 2.27 0.24 0.32 0.15 0.76 28.3 23.7 20.7 6.67 18.0 6 1.25 1.6 0.20 2.21 0.23 0.33 0.16 0.86 28.0 23.7 22.7 9.33 17.7 6 3.0 1.5 0.23 2.33 0.24 0.31 0.15 0.60 32.0 23.3 21.3 6.67 21.7 8 1.25 1.6 0.21 2.35 0.24 0.33 0.16 0.74 32.3 25.3 22.7 8.33 18.0 8 3.0 1.5 0.22 2.54 0.26 0.31 0.16 0.71 29.3 21.3 21.3 5.67 16.7 Significance z NS NS NS NS NS NS NS NS NS NS NS z Regression analysis where NS, *L,: Not significant, and linear significance at the 0.05 level, respectively

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101 Table A 6 Effect of four fertilizer levels on mineral nutrient concentrations of Adenium obesum inch pots after 20 weeks (July December 2011). Pot Size (L) Fertilizer (g/L) N P K Mg Ca S Na Fe Mn B Cu Zn 1.25 2 1.4 0.19 2.20 0.24 0.36 0.15 0.17 31.7 18.3 20.7 9.7 20.0 1.25 4 1.6 0.19 2.09 0.24 0.36 0.15 0.12 32.0 24.3 22.7 10.0 20.0 1.25 6 1.6 0.20 2.21 0.23 0.33 0.16 0.86 28.0 23.7 22.7 9.3 17.7 1.25 8 1.6 0.21 2.35 0.24 0.33 0.16 0.74 32.3 25.3 22.7 8.3 18.0 3.0 2 1.5 0.20 2.40 0.25 0.35 0.16 0.10 32.0 27.3 25.3 8.7 16.0 3.0 4 1.5 0.21 2.27 0.24 0.32 0.15 0.76 28.3 23.7 20.7 6.7 18.0 3.0 6 1.5 0.23 2.33 0.24 0.31 0.15 0.60 32.0 23.3 21.3 6.7 21.7 3.0 8 1.5 0.22 2.54 0.26 0.31 0.16 0.71 29.3 21.3 21.3 5.7 16.7 Significance z NS *L *L NS NS NS *L NS NS NS *L NS z Regression an alysis where NS and *L indicates: Not significant and linear significance at the 0.05 level, respectively.

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102 Table A 7 Effect of four fertilizer levels on mineral nutrient concentrations of Adenium obesum inch pots a fter 20 weeks (July December 2011). Fertilizer (g/L) Pot Size N P K Mg Ca S Na Fe Mn B Cu Zn 2 1.25 1.7 0.09 0.69 0.85 1.4 0.21 0.78 29.0 70.0 43.3 5.0 11.0 2 3.0 2.1 0.10 0.61 0.91 1.7 0.24 0.55 42.3 102.0 40.7 5.0 9.3 4 1. 25 2.1 0.09 0.40 0.80 1.5 0.24 0.47 39.0 91.3 40.3 6.0 11.0 4 3.0 2.2 0.10 0.50 0.87 1.5 0.23 0.41 38.7 102.7 37.7 4.7 8.7 6 1.25 2.1 0.10 0.47 0.91 1.5 0.23 0.46 33.3 104.0 45.0 5.3 10.0 6 3.0 2.3 0.12 0.60 0.86 1.6 0.26 0.35 42.7 130.7 4 4.3 4.3 9.0 8 1.25 2.3 0.11 0.46 0.91 1.7 0.26 0.35 45.3 121.0 45.3 6.0 9.7 8 3.0 2.4 0.12 0.70 0.84 1.5 0.25 0.36 51.0 113.0 43.3 5.0 9.0 Significance z **L **L *Q NS NS *L **L *L *L NS NS NS z Regression analysis where NS, *L, *Q and **L: Not significant, linear significance at the 0.05 level, quadratic significance at the 0.05 level, and linear significance at the 0.001 level, respectively.

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103 Table A 8 Effect of four fertilizer levels on mineral nutrient concentrations of Adenium obesum inch pots after 20 weeks (July December 2011). Pot Size (L) Fertilizer (g/L) N P K Mg Ca S Na Fe Mn B Cu Zn 1.25 2 1.7 0.09 0.69 0.85 1.4 0.21 0.78 29.0 70.0 43.3 5.0 11.0 1.25 4 2.1 0.09 0.40 0.80 1.5 0.24 0.47 39.0 91.3 40.3 6.0 11.0 1.25 6 2.1 0.10 0.47 0.91 1.5 0.23 0.46 33.3 104.0 45.0 5.3 10.0 1.25 8 2.3 0.11 0.46 0.91 1.7 0.26 0.35 45.3 121.0 45.3 6.0 9.7 3 .0 2 2.1 0.10 0.61 0.91 1.7 0.24 0.55 42.3 102.0 40.7 5.0 9.3 3.0 4 2.2 0.10 0.50 0.87 1.5 0.23 0.41 38.7 102.7 37.7 4.7 8.7 3.0 6 2.3 0.12 0.60 0.86 1.6 0.26 0.35 42.7 130.7 44.3 4.3 9.0 3.0 8 2.4 0.12 0.70 0.84 1.5 0.25 0.36 51.0 113.0 43.3 5.0 9.0 Significance z NS *L NS NS NS NS NS NS NS NS *L *L z Regression analysis where NS and *L indicates: Not significant and linear significance at the 0.05 level, respectively.

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104 Table A 9 Effect of four fertilizer levels on minera l nutrient concentrations of Adenium obesum pots after 20 weeks (July December 2011). Pot Size (L) Fertilizer (g/L) N P K Mg Ca S Na Fe Mn B Cu Zn 1.25 2 1.3 0.10 1.2 0.80 1.1 0.17 0.62 44.7 18.7 31.0 8.7 39.3 1 .25 4 1.6 0.10 0.68 0.59 1.1 0.17 0.62 44.7 25.0 27.7 8.3 32.7 1.25 6 1.8 0.11 0.93 0.52 0.93 0.19 0.39 32.3 27.0 27.7 8.3 27.3 1.25 8 2.0 0.13 1.0 0.53 0.89 0.23 0.37 29.7 28.0 28.3 8.3 27.3 3.0 2 1.6 0.11 1.0 0.77 1.0 0.23 0.46 29.0 27.7 26.3 8.0 29.7 3.0 4 1.7 0.11 1.1 0.57 0.81 0.22 0.38 38.3 27.7 26.0 8.0 32.0 3.0 6 1.9 0.15 1.3 0.56 0.71 0.25 0.34 25.3 21.7 25.0 8.0 24.0 3.0 8 2.2 0.15 1.6 0.56 0.75 0.27 0.35 33.0 25.7 27.7 8.3 22.7 Significance z NS *L *L NS *L *L NS NS NS *L NS NS z Regression analysis where NS and *L indicates: Not significant and linear significance at the 0.05 level, respectively.

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105 Figure A 10 Interaction of fertilizer and pot size on the soluble salt concentration of Adenium o 0 500 1000 1500 2000 2500 3000 2 4 6 8 Soluble Salt Concentration Fertilizer Rate (g/L) 1.25 L 3.0 L

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106 Figure A 11 5.6 5.8 6 6.2 6.4 6.6 6.8 7 7.2 7.4 2 4 6 8 pH Fertilizer Rate (g/L) 1.25 L 3.0 L

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107 Table A 12 Effect of four fertilizer levels on mineral nutrient concentrations of Adenium obesum 1. 25 L and 3.0 L pots after 20 weeks (July December 2011). Pot Size (L ) Fertilizer (g rams/L ) N P K Mg Ca S Na Fe Mn B Cu Zn 1.25 2 1.3 0.10 1. 2 0.80 1.1 0.17 0.62 44.7 18.7 31.0 8.7 39.3 1.25 4 1. 6 0.10 0.7 0.59 1. 1 0.17 0.62 44.7 25.0 27.7 8.3 32.7 1.25 6 1. 8 0.11 0.9 0.52 0.9 0.19 0.39 32.3 27.0 27.7 8.3 27.3 1.25 8 2. 0 0.13 1.0 0.53 0. 9 0.23 0.37 29.7 28.0 28.3 8.3 27.3 3.0 2 1.6 0.11 1.0 0.77 1.0 0.23 0.46 29.0 27.7 26.3 8.0 29.7 3.0 4 1.7 0.11 1.1 0.57 0.8 0.22 0.38 38. 3 27.7 26.0 8.0 32.0 3.0 6 1.9 0.15 1.3 0.56 0.7 0.25 0.34 25.3 21.7 25.0 8.0 24.0 3.0 8 2.2 0.15 1.6 0.56 0.7 0.27 0.35 33.0 25.7 27.7 8.3 22.7 Significance z NS L* L* NS L* L* NS NS NS L* NS NS z Regression analysis where NS and L* indicates: Not significant and linear significance at the 0.05 level, respectively.

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108 Table A 13 Effect of four fertilizer levels on mineral nutrient concentrations of Adenium obesum inch pots after 20 weeks ( July December 2011). Fertilizer (g/L) Pot Size N P K Mg Ca S Na Fe Mn B Cu Zn 2 1.25 1.3 0.12 1.4 0.66 0.45 0.16 1.2 310.3 24.7 18.0 10.3 24.0 2 3.0 1.7 0.14 1.9 0.75 0.47 0.19 1.0 395.7 33.7 16.0 11.0 24.0 4 1.25 1.7 0.14 1 .8 0.66 0.39 0.19 0.93 264.3 21.7 16.0 8.7 19.7 4 3.0 1.9 0.19 2.7 0.89 0.29 0.25 0.79 139.7 14.3 14.0 7.0 23.7 6 1.25 2.1 0.16 2.1 0.68 0.39 0.22 1.0 222.7 20.3 16.7 9.0 22.7 6 3.0 2.3 0.23 2.5 0.86 0.42 0.25 0.74 260.7 20.7 18.7 9.7 21.0 8 1.25 2.2 0.16 2.2 0.84 0.48 0.25 0.90 413.7 28.3 18.0 11.0 25.0 8 3.0 2.8 0.26 3.3 1.12 0.43 0.30 0.90 148.0 27.0 20.7 9.3 21.3 Significance z **L *L *L *L *Q *L NS NS NS *L* Q NS NS z Regression analysis where NS, *L, *Q a nd **L: Not significant, linear significance at the 0.05 level, quadratic significance at the 0.05 level, and linear significance at the 0.001 level, respectively.

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109 Table A 14 Effect of four fertilizer levels on mineral nutrient concentratio ns of Adenium obesum inch pots after 20 weeks (July December 2011). Pot Size (L) Fertilizer (g/L) N P K Mg Ca S Na Fe Mn B Cu Zn 1.25 2 1.3 0.12 1.4 0.66 0.45 0.16 1.2 310.3 24.7 18.0 10.3 24.0 1.25 4 1.7 0.14 1.8 0. 66 0.39 0.19 0.93 264.3 21.7 16.0 8.7 19.7 1.25 6 2.1 0.16 2.1 0.68 0.39 0.22 1.0 222.7 20.3 16.7 9.0 22.7 1.25 8 2.2 0.16 2.2 0.84 0.48 0.25 0.90 413.7 28.3 18.0 11.0 25.0 3.0 2 1.7 0.14 1.9 0.75 0.47 0.19 1.0 395.7 33.7 16.0 11.0 24.0 3 .0 4 1.9 0.19 2.7 0.89 0.29 0.25 0.79 139.7 14.3 14.0 7.0 23.7 3.0 6 2.3 0.23 2.5 0.86 0.42 0.25 0.74 260.7 20.7 18.7 9.7 21.0 3.0 8 2.8 0.26 3.3 1.12 0.43 0.30 0.90 148.0 27.0 20.7 9.3 21.3 Significance z *L *L *L *L NS *L NS NS NS NS NS N S z Regression analysis where NS and *L indicates: Not significant and linear significance at the 0.05 level, respectively.

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110 Figure A 15 10.0 20.0 30.0 40.0 50.0 60.0 70.0 80.0 2 4 6 8 Fertilizer Rate grams/L 1.25L 3.0L

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111 Figure A 16 0.4 0.5 0.5 0.6 0.6 0.7 2 4 6 8 Fertilizer Rate grams/L 1.25L 3.0L

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112 Figure A 17 10 15 20 25 30 35 40 45 50 2 4 6 8 Fertilier Rate grams/L 1.25L 3.0L

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113 LIST OF REF ERENCES Blazich, F.A. 1988. Adventitious root formation of cuttings, p. 61 69. In: Davis, T.D., Haissig, B.E., and Sankhla, N. (eds.). Mineral nutrition and adventitious rooting. Dioscorides Press, Portland, OR. Broschat, T.K., D.R. Sa ndrock, M.L. Elliott, and E.F. Gilman. 2008. Effects of fertilizer type on quality and nutrient content of established landscape plants in Florida. Hort. Technology. 18: 278 285. Brown, S. H. 2012. Adenium obesum A report. Institute of Food and Agricultu ral Science, Lee County Extension. Cerveny, C. 2006. Stock plant management of tropical perennials. University of Florida. . College of Tropical Agricult ure and Human Resources, Ornamentals and Flowers 24 : 1 2 < www.ctahr. hawaii .edu/oc/freepubs/pdf/OF 31.pdf >. Das, A.B., S. M ohanty, and P. Das. 1999. Chromosome number, karyotype, and nuclear DNA content in some Adenium species of the family Apocynaceae. Cytobios. 98:95 104. Davis, T.D., B.E. Haissig, and N. Sankhla. 1988. Adventitious root formation in cuttings. Discorides Pre ss. Portland, OR. 39. Dimmitt, M.G. and C. Hanson. In Press. A horticultural evaluation of the genus Aden ium Desert Plants. Dimmitt, M.G. and C. Hanson. 1991. The genus Adenium in cultivation. Part 1: A. obesum and A. multiflorum Cactus and Succulent J. 63: 223 225. Dimmitt, M.G. 1998. Adenium culture, growing large specimens, quickly. Cactus and Succulent J. 20: 59 64. Dimmitt, M.G., G. Joseph, and D. Palzkill. 2009. Adenium : sculptural elegance, floral extravagance. Scathingly Brilliant Idea. Tucson, AZ. Hargreaves, B.J. 2002. How many species of Adenium are there? Asklepios. 85: 23. Hartmann, H.T., D.E. Kester, F.T. Davies, and R.L. Geneve. 2002. Hartmann and 880.

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114 Hastuti, D., Suranto, and P. Setyono. 2009. Variation of morphology, karyotype, and protein band pattern of Adenium ( Adenium obesum ) varieties. Nusantara Biosci. 1: 78 83. Hata, T.Y., A.H. Hara, M.A. Nagao, and B.K.S. Hu. 1994. Hort. Technology. 4: 159 162. Hoft, M., R. Verpoorte, and E. Beck. 1996. Growth and alkaloid content in leaves of Tabernaemontana pachysiphon Sta pf (Apocynaceae) as influenced by light intensity, water, and nutrient supply. Oecologia. 107: 160 169. Huante, P., E. Rincon, and I. Acosta. 1995. Nutrient availability and growth rate of 34 woody species from a tropical deciduous forest in Mexico. Functi onal Ecology. 9: 849 858. Joiner, J.N., C.A. Conover, R.T. Poole. 1981. Nutrition and Fertilization, p.229 265. In: Joiner, J.N. (eds.) Foliage Plant Production. Prentice Hall, Inc. Englewood Cliffs, NJ. Kanchanapoom, K., S. Sunheem, and K. Kanchanapoom. 2010. In vitro propagation of Adenium obesum (Forssk.) Roem. and Schult. Not. Bot. Hort. Agro. Cluji Napoca. 38: 209 213. Kessler, J.R. 1998. Greenhouse production of annual Vinca. Alabama Cooperative Extention System. < www.aces.edu/pubs/docs/A/ANR 1119/ANR 1119.pdf > Landon, A.L. and T.J. Banko. 2005. Propagation of Vinca minor by single node cutting. J. Environ. Hort. 23: 1 3. Liu, T., B. Chen, and X. Chan. 2004. The effect of hormone o n callus culture of Desert Rose Adenium obesum Economic Forest Researches. Mart, M. 2012. Strike a pose: Mandevilla vogue. Grower Talks. 76: 1 8. McCulla, F.A.C. 1973. Oleander ( Nerium oleander culture). J. Hort. 50: 26 27. McLaughlin, J. and J. Garofalo 2002. Desert Rose, Adenium obesum : nursery production. University of Florida Cooperative Extension Service. Miami Dade County Extension. 66: 1 2. < http://miam i dade.ifas.ufl.edu/old/programs/commorn/publications/desert rose.PDF > Oyen, L.P.A. 2008. Schmelzer Gh. In: Gurib Fakim (eds.) Plant resources of tropical Africa. Wageningen. Backhuys. Plaizier, A.C. 1980. A revision of Adenium Roem. And Schult. and of D iplorhynchus Welw. Ex Fic. and Hiern (Apocynaceae). Mededelingen Landbouwhogeschool. 80: 1 40.

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115 Plaza, B.M., S. Jimenez, M. Sebastian, M. Lao, J. Contreras, and M. Segura. 2009. Growth and nutrient evolution of Dipladenia sanderi L. (Apocyanaceae) crop in Mediterranean climate. Acta Hort. 1: 571. Poole, R.T. and C.A. Conover. 1976. Chemical composition of good quality tropical plants. Proc. Fl. State Hort. Soc. 89: 307 308. Popenoe, Juanita. 2008. Oleander Nerium oleander University of Florida IFAS. < cfex tension. ifas .ufl.edu/documents/ Oleander .pdf >. Raven, P.H., R.F. Evert, and S.E. Eichhorn. 2005. Biology of plants. W.H. Freeman and company publishers. Rowley, G.D. 1987. Caudiceform and Pachycaul Succulents. Strawberry Press. Mill Valley, CA. Rowley, G.D 1999. Adenium and Pachypodium Cactus File Handbook No. 5. UK. Srivastava, L.M. 2002. Plant growth and development: hormones and environment. Academic Press. Amsterdam. Taiz, L. and E. Zeiger. 2006. Plant physiology. Sinauer Associates, Inc. Sunderland, MA. van Ierse, M.W. R.B. Beverly, P.A. Thomas, J. G. and H.A. Mills. 1999. Nitrogen, phosphorus, and potassium effects on pre and post transplant growth of salvia and Vinca seedlings. J. Plant Nutrition. 22: 1403 1413. Xiaomei, L., X. Chen, and B. Chen. 2003. Studies on rooting conditions of Adenium obesum J. Hubei Agr. College. 23: 91 94.

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116 BIOGRAPHICAL SKETCH Kaitly n McBride obtained her Bachelor of Science degree in landscape and nursery horticulture from the University of Florida in 2010 Her nursery experience includes 2 years at a garden center in Orlando Florida Currently, Kaitlyn is a graduate research assistant at the University of Florida where her influences to the art and science of horticulture continue to increase.