Dwarfing in ornamentals

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Dwarfing in ornamentals

  1. 1. Indian Agricultural Research Institute, New Delhi (use of shrubs as potted plants) Pratiksha Kumari 20306 Division of Floriculture and Landscaping
  2. 2. IMPORTANCE OF DWARFINGControl of plant growth imp in modern plant production.Short, homogenous plants, more robustEasy to harvest, transport and sell.Compact growth desirable, difficult to obtain by traditionalbreeding.Cereals, grasses, fruit trees and ornamentals, areregularly treated chemically to control their stature andflowering time. Indian Agricultural Research Institute, New Delhi
  3. 3. IMPORTANCE OF DWARFING FORORNAMENTAL SHRUBS•Dwarf ornamental shrubs, used as permanentlandscaping, pot plants.•Require little care compared to seasonal bedding plantsor large ornamental shrubs.•Same foliage and flowers as large shrubs.•Typically 1-3 feet tall, use lesser water and fertilizer. Indian Agricultural Research Institute, New Delhi
  4. 4. DWARFING TECHNIQUES:Synthetic Growth regulatorsPhotopeiodic controlThermoperiodic controlWater StressBreeding approaches Indian Agricultural Research Institute, New Delhi
  5. 5. Indian Agricultural Research Institute, New Delhi
  6. 6. Effects of Water Stress and SelectedPlant Growth Retardants on Growth and Flowering of ‘Raspberry Ice’ Bougainvillea (S. Ma and M. Gu ) Acta Horticulture ;2012. 937, 237-242. Indian Agricultural Research Institute, New Delhi
  7. 7. Needs a lot of labor-intensivepruning (as potted plant).PGRs alternatives to frequentprunningDaminozide, paclobutrazol andchlormequat reported to be effectivein controlling plant height.to examine the effects ofWS, daminozide and chlormequat ongrowth and flowering of „RaspberryIce‟ bougainvillea. Indian Agricultural Research Institute, New Delhi
  8. 8. MATERIALS AND METHODS Plant Materials and Culture195 12-cm tall ‘Raspberry Ice’ bougainvilleacuttings usedEvery 3 cutting were potted up in 20 cm potsPlants irrigated as necessary with water-solublefertilizer 200 mg (20−4−6)Prunned to 15cm in height . Indian Agricultural Research Institute, New Delhi
  9. 9. Water Stress Application• Plants treated with 2-week, 3-week and 4- week WS• Tap water (150 ml) provided to each WS plant after that .• Saucers placed under pots to ensure the 150 ml water was fully absorbed Indian Agricultural Research Institute, New Delhi
  10. 10. PGR Application-Daminozide (1,250, 2,500, and 3,750 ppm)Chlormequat (300, 600, 900 ppm)Daminozide/chlormequat (800/1,000, 1,250/1,250, and2,500/ 1,500 ppm)Foliar sprayed with a trigger sprayer at 20 mL PGRsolution/pot .Control plants were not subject to PGR or WS treatment. Indian Agricultural Research Institute, New Delhi
  11. 11. RESULTS :Growth• Water stress showed significant impact on both plant height and width• PGR treatments did notFlowering• All treatments show higher %age of flowering (33.3% to 60%).• Daminozide as foliar spray, more flowers/pot than other treatments . Indian Agricultural Research Institute, New Delhi
  12. 12. Table of WS and PGR applied to growth of “Raspberry Ice” Bougainvillea in 2009 Treatments Height (cm) Width (cm) Control 30.8 84.9 WS 22.5 66.5 Daminozide 27.9 87.0 Chlormequat 33.0 87.0 Daminozide/Chlor 30.7 92.9 mequatWS (2 week, 3 week, 4 week water stress combined)Daminozide (1,250,2500, and 3750mg/L treatments combined)Chlormequat (300, 600, and 900 mg/L treatments combined)Daminozide/Chlormequat (800/1000,1250/1250,2500/1500 mg/L treatments combined)
  13. 13. CASE STUDY-IIIndian Agricultural Research Institute, New Delhi
  14. 14. Use of uniconazole to control height of Hibiscus rosa sinensis (Steven E. Newman et.al) HortScience; 1989 24(6):1041 Indian Agricultural Research Institute, New Delhi
  15. 15.  For growing in pots and forlandscaping dwarf plants preferred.Chloromequat chloride induceshortened internodes & darkengreen leaves (Wilkins and Kotecki,1985).Research evaluates theeffectiveness of Uniconazole forcontrol of plant height, width, leafdistortion and no of breaks/ plant Indian Agricultural Research Institute, New Delhi
  16. 16. METHOD: Rooted cuttings of hibiscus rosa sinensis l. Cv „brilliant‟ selectedPlants fertilized weekly with 200 mg n/ Litre (20N-8.6P-16.6K) at each irrigation. Plants pinched and flower buds were removed Plants sprayed with uniconazole at 0, 10, 15, or 20 mg a.i./ Litre. Ten plants treated at each of the given rates. Indian Agricultural Research Institute, New Delhi
  17. 17. RECORDING OF OBSERVATIONS:Data collected 77 days after treatments wereapplied, when all hibiscus plants were in full flower.plant height (from the potting mediun surface) width (the average of two measurements takenperpendicular to each other ), stem length, leaf distortion, number of breaks, anddays to flower. Indian Agricultural Research Institute, New Delhi
  18. 18. RESULTS :Plant heightHeight were reduced by all application rates of uniconazole, with themain effect on height occurring at rates <15 mg./litre 80 60 40 plant height(cm) 20 Uniconazole(mg a.i./litre) 0 0 5 10 15 20 Indian Agricultural Research Institute, New Delhi
  19. 19. Width plant width was reduced linearly foreach unit increase in concentration 45 40 35 30 25 plant width(cm) 20 15 10 5 0 0 5 10 15 20 Indian Agricultural Research Institute, New Delhi
  20. 20. Leaf distortion significantly increased with increasedapplication rates of uniconazole . where 1=no distortion to 10=severe 10 9 8 7 6 leaf distortion 5 4 3 2 1 Uniconazole (mg a.i./liter) 0 0 5 10 15 20 Indian Agricultural Research Institute, New Delhi
  21. 21. Number of breaks It is increased with increased uniconazole application 25 20 15 no of breaks 10 5 0 0 5 10 15 20 Indian Agricultural Research Institute, New Delhi
  22. 22. INFERENCES :Maximum reduction in plant height with Uniconazole application at15 mg/litre. Leaf distortion maximum at 15 mg/L. plants treated with 10 mg/Lwere of high quality with minimal levels of distortion and curling15 - 20 mg/L severe distortion and of poor quality.Uniconazole @ 10 mg a.i./L controlled heightpromising method for height control and plant quality improvement. Indian Agricultural Research Institute, New Delhi
  23. 23. Indian Agricultural Research Institute, New Delhi
  24. 24. Application of growth regulators toOrnamental shrubs for use as interior decoration ( Joustra M. K. et.al) Acta Horticulturae ;1989 251:359-369.Indian Agricultural Research Institute, New Delhi
  25. 25. Screening of shrubs for indoorperformance have startedThe need for regulation of growthand / or flowering have becomeevident.Aspects of such experiments onClematis , Hydrangeamacrophylla, Rhododendron (azalea), Skimmia sps, Hibiscus rosasinensis, Choisya ternata, Viburnumtinus, Vaccinium vitis, briefly discussedhere. Indian Agricultural Research Institute, New Delhi
  26. 26. CLEMATIS• Branching of clematis „Capitan Thuilleaux‟ can be improved with dikegulac-Na and promalin (1:1 6-BAP+GA4+7)• 14 mL promalin/L spray solution is sufficient to get good branching .• For compact growth of clematis cvs paclobutrazol gives good results .HYDRANGEA MACROPHYLLA• Plant height of hydrangea macrophylla Cv was effectively controlled by daminozide , ancymidol, or by paclobutrazol• Not by chlormequat.• Gibberelin together with lightning speeded up flowering .• Only ancymidol and paclobutrazol stimulated inflorescence initiation of plants. Indian Agricultural Research Institute, New Delhi
  27. 27. RHODODENDRON (AZALEAS )• Retardation of growth by daminozide, chlormequat, or by paclobutrazol.• Branching induced by spray application of mefluidide.• Application of acifluorfen as a soil drench promote more shoot.SKIMMIA SPECIES• Skimmia plants perform very well indoor .• So studies have been conducted on the effect of GA and CT on growth and• branching of the second flush of this plant. Indian Agricultural Research Institute, New Delhi
  28. 28. CHOISYA TERNATA• Growth can be retarded by the use of paclobutrazol, but not with other GRs.• Since flowering than is also delayed with this application means other than use of GRs have to be worked on.VIBURNUM TINUS• Heavy growth retardation was observed in treatment with paclobutrazol and high conc of daminozide or ethephon.• Initiation of flowering during early stage of growth can also be achieved by the use of paclobutrazol Indian Agricultural Research Institute, New Delhi
  29. 29. HIBISCUS ROSA SINENSIS• Application of growth retardant chlormequat immediately after topping• And a second spray when the plants reach 5cm height VACCINIUM VITIS• Treating of plants with a combination of daminozide and ethephon ,together with a cold treatment just before forcing to flowering resulted in compact growth of the plants.• This method offers good possiblity of using vaccinium as pot plant. Indian Agricultural Research Institute, New Delhi
  30. 30. •Use of growth regulators in dwarfing of ornamental shrubs for use as potplants can be undertaken.•There are many side-effects associated with use of GRs, so before their useproper study must be conducted.•There are many GRs which along with suppressing growth also promote theformation of flower buds.•Study on interaction of climatic factors and GRs treatment still needsattention.•Breeding on dwarfing can also sometimes overcome the use of GRs. Indian Agricultural Research Institute, New Delhi

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