During the early spring in the woodlands of eastern North America, Phlox drummondii emerges as a perennial plant adorned with a profusion of blooms in shades of blue, purple, pink, or white. Its evergreen nature adds to its charm. To manage the growth of plants or specific plant parts, plant growth regulators (PGRs) are synthesized and employed, serving as valuable tools for controlling and directing the development of various plant species. A diverse range of ornamental plants, such as Phlox drummondii, have been documented to receive exogenous applications of plant growth regulators (PGRs). Among these regulators, gibberellins (GA) play a vital role by delaying senescence in flowers and promoting the breaking of dormancy in seeds, bulbs, and corms of ornamental plants. The experiment aimed to assess the performance and determine the optimal growth medium for Phlox. Five distinct growth media were employed as treatments during the study, which took place in the Horticulture Department of Gomal University. Collected data underwent analysis through ANOVA and Tuckey HSD tests. The study’s findings revealed that the highest plant height (16 cm) was observed in the control treatment with PGR 1, closely followed by PGR 2 (11.5 cm). The treatment labeled as T5, composed of a mixture of 1/3 sand, 1/3 poultry manure, and 1/3 soil, demonstrated the most favorable results across multiple parameters such as bud initiation (BI), first flower emergence (FFE), flowers per plant (FPP), branches per plant (BPP), leaves per plant (LPP), number of roots (NR), field life of flowers (FLF), and flower diameter (FD). T4, T3, T2, and T1 treatments also exhibited similar positive outcomes, aligning with the promising performance of T5.

1. Landis JB, Bell CD, Hernandez M, et al. Evolution of floral traits and impact of reproductive mode on diversification in the Phlox family (Polemoniaceae). Molecular Phylogenetics and Evolution 2018; 127: 878–890. doi: 10.1016/j.ympev.2018.06.035.

2. Munir M, Alhajhoj MR. Plant height control of obligate long day herbaceous annuals using plant growth retardants and light. Journal of Applied Horticulture 2017; 19(3): 241–244. doi: 10.37855/jah.2017.v19i03.41.

3. Zale PJ, Robarts DWH, Jourdan P. Genome size and ploidy levels of creeping phlox and related germplasm of mat-forming taxa from eastern and western North America. Scientia Horticulturae 2016; 203: 53–61. doi: 10.1016/j.scienta.2016.02.039.

4. Lee‐Yaw JA, Kharouba HM, Bontrager M, et al. A synthesis of transplant experiments and ecological niche models suggests that range limits are often niche limits. Ecology Letters 2016; 19(6): 710–722. doi: 10.1111/ele.12604.

5. Khipla N, Kaur J, Gosal SK, et al. Integrated nutrient management to improve soil health, nutrient uptake and growth of Poplar (Populus deltoides) seedlings in nursery conditions. Indian Journal of Agroforestry 2021; 23(2): 45–52.

6. Jarvis DE, Maughan PJ, DeTemple J, et al. Chromosome-scale genome assembly of Gilia yorkii enables genetic mapping of floral traits in an interspecies cross. Genome Biology and Evolution 2022; 14(3): evac017. doi: 10.1093/gbe/evac017.

7. Fatima S, Aslam N, Khalid S. Effects of copper toxicity on different growth attributes of Phlox drummondii. Environment & Ecosystem Science 2021; 5(1): 58–63. doi: 10.26480/ees.01.2021.58.63.

8. Majetic CJ, Levin DA, Raguso RA. Divergence in floral scent profiles among and within cultivated species of Phlox. Scientia Horticulturae 2014; 172: 285–291. doi: 10.1016/j.scienta.2014.04.024.

9. Karnawat M, Trivedi SK, Meena RK, Nagar D. A review on haploid and double haploids in ornamental plants. Current Research in Agriculture and Farming 2021; 2(3): 1–7. doi: 10.18782/2582-7146.138.

10. Sumalan RL, Croitor L, Petric M, et al. P-aminobenzoate organic salts as potential plant growth regulators for tomatoes. Molecules 2020; 25(7): 1635. doi: 10.3390/molecules25071635.

11. Shah SH, Islam S, Parrey ZA, Mohammad F. Role of exogenously applied plant growth regulators in growth and development of edible oilseed crops under variable environmental conditions: A review. Journal of Soil Science and Plant Nutrition 2021; 21(4): 3284–3308. doi: 10.1007/s42729-021-00606-w.

12. Sajjad Y, Jaskani MJ, Qasim M, et al. Pre-plant soaking of corms in growth regulators influences the multiple sprouting, floral and corm associated traits in Gladiolus grandiflorus L. Journal of Agricultural Science 2015; 7(9): 173–181. doi: 10.5539/jas.v7n9p173.

13. Krug BA, Whipker BE, McCall I. Hyacinth height control using preplant bulb soaks of flurprimidol. HortTechnology 2006; 16(2): 370–375. doi: 10.21273/HORTTECH.16.2.0370.

14. Mahgoub M, El-Aziz NAA, Mazhar A. Response of Dahlia psinnata L. plant to foliar spray with putrescine and thiamine on growth, flowering and photosynthetic pigments. American-Eurasian Journal of Agricultural & Environmental Sciences 2011; 10(5): 769–775.

15. Ramzan F, Younis A, Riaz A, et al. Pre-planting exogenous application of gibberellic acid influences sprouting, vegetative growth, flowering, and subsequent bulb characteristics of ‘Ad-Rem’ tulip. Horticulture, Environment, and Biotechnology 2014; 55(6): 479–488. doi: 10.1007/s13580-014-0113-7.

16. Carey DJ, Fair BA, Buhler W, et al. Growth control and flower promotion of Salvia with benzyladenine foliar sprays. Journal of Applied Horticulture 2013; 15(2): 87–89. doi: 10.37855/jah.2013.v15i02.15.

17. Sajjad Y, Jaskani MJ, Ashraf MY, et al. Response of morphological and physiological growth attributes to foliar application of plant growth regulators in gladiolus ‘white prosperity’. Pakistan Journal of Agricultural Sciences 2014; 51(1): 123–129.

18. Darras AI, Joyce DC, Terry LA. Methyl jasmonate and acibenzolar-S-methyl protect cut Freesia hybrida inflorescences against Botrytis cinerea, but do not act synergistically. The Journal of Horticultural Science and Biotechnology 2011; 86(1): 74–78. doi: 10.1080/14620316.2011.11512728.

19. Iqbal D, Habib U, Abbasi NA, Chaudhry AN. Improvement in postharvest attributes of Zinnia (Zinnia elegans cv. Benarys Giant) cut flowers by the application of various growth regulators. Pakistan Journal of Botany 2012; 44(3): 1091–1094.

20. Tütüncü M, Tolga I, Sevindik B, Mendi YY. In vitro haploidy techniques in ornamental plants. Tarım Bilimleri Araştırma Dergisi 2017; 10(1): 1–6.

21. Visioni A, Gyawali S, Selvakumar R, et al. Genome wide association mapping of seedling and adult plant resistance to barley stripe rust (Puccinia striiformis f.sp. hordei) in India. Frontiers in Plant Science 2018; 9: 520. doi: 10.3389/fpls.2018.00520.

22. Tiku AR, Razdan MK, Raina SN. Production of triploid plants from endosperm cultures of Phlox drummondii. Biologia Plantarum 2014; 58(1): 153–158. doi: 10.1007/s10535-013-0372-7.

23. Gonçalves AN, Matsumoto SN, Ramos PAS, et al. Inhibitor of gibberellin biosynthesis in ornamental peppers. Horticultura Brasileira 2022; 40(1): 48–55. doi: 10.1590/s0102-0536-20220106.

24. Głąb T, Szewczyk W, Gondek K, et al. Effect of plant growth regulators on visual quality of turfgrass. Scientia Horticulturae 2020; 267: 109314. doi: 10.1016/j.scienta.2020.109314.

25. Dar TH, Raina SN, Goel S. Cytogenetic and molecular evidences revealing genomic changes after autopolyploidization: A case study of synthetic autotetraploid Phlox drummondii hook. Physiology and Molecular Biology of Plants 2017; 23(3): 641–650. doi: 10.1007/s12298-017-0445-8.

26. Wang X, Cheng ZM, Zhi S, Xu F. Breeding triploid plants: A review. Czech Journal of Genetics and Plant Breeding 2016; 52(2): 41–54. doi: 10.17221/151/2015-CJGPB.

27. Shavrukov S, Kurishbayev A, Jatayev S, et al. Early flowering as a drought escape mechanism in plants: How can it aid wheat production? Frontiers in Plant Science 2017; 8: 1950. doi: 10.3389/fpls.2017.01950.

28. Bhattarai B, Maitra S, Thokchom R. Assessment of height, earliness and biomass production in selected winter flowering ornamental annuals for better utilization in landscaping. The Pharma Innovation Journal 2019; 8(4): 59–64.

29. Wu W, Liao T, Du K, et al. Transcriptome comparison of different ploidy reveals the mechanism of photosynthetic efficiency superiority of triploid poplar. Genomics 2021; 113(4): 2211–2220. doi: 10.1016/j.ygeno.2021.05.009.

30. Hopkins R, Rausher MD. The cost of reinforcement: Selection on flower color in allopatric populations of Phlox drummondii. The American Naturalist 2014; 183(5): 693–710. doi: 10.1086/675495.

31. Bunn E, Turner SR, Dixon KW. Biotechnology for saving rare and threatened flora in a biodiversity hotspot. In Vitro Cellular & Developmental Biology-Plant 2011; 47: 188–200. doi: 10.1007/s11627-011-9340-0.

32. Purohit SS (editor). Hormonal regulation of plant growth and development. 1st ed. Dordrecht: Springer Dordrecht; 2012. p. 234. doi: 10.1007/978-94-015-3950-0.

33. Mikovski AI, Silva NT, Silva LAS, et al. From endosperm to triploid plants: A stepwise characterization of the de novo shoot organogenesis and morpho-agronomic aspects of an ornamental passion fruit (Passiflora foetida L.). Plant Cell, Tissue and Organ Culture 2021; 147(2): 239–253. doi: 10.1007/s11240-021-02120-4.

34. Münzbergová Z. Colchicine application significantly affects plant performance in the second generation of synthetic polyploids and its effects vary between populations. Annals of Botany 2017; 120(2): 329–339. doi: 10.1093/aob/mcx070.

35. Hopkins R. The evolution and genetics of reinforcement in Phlox drummondii [PhD thesis]. Durham: Duke University; 2010.

36. García-Fortea E, García-Pérez A, Gimeno-Páez E, et al. Ploidy modification for plant breeding using in vitro organogenesis: A case in eggplant. Methods in Molecular Biology 2021; 2264: 197–206. doi: 10.1007/978-1-0716-1201-9_14.

37. Xue H, Zhang B, Tian JR, et al. Comparison of the morphology, growth and development of diploid and autotetraploid ‘Hanfu’ apple trees. Scientia Horticulturae 2017; 225: 277–285. doi: 10.1016/j.scienta.2017.06.059.

38. Farinas C, Jourdan PS, Hand FP. Flaming Phlox and the ubiquitous powdery mildew disease. Plant Health Progress 2020; 22(1): 11–20. doi: 10.1094/PHP-08-20-0070-RV.

39. Weng JK, Ye M, Li B, Noel JP. Co-evolution of hormone metabolism and signaling networks expands plant adaptive plasticity. Cell 2016; 166(4): 881–893. doi: 10.1016/j.cell.2016.06.027.

40. Farinas C. Understanding the powdery mildew disease of the ornamental plant Phlox: Combining applied and basic research [PhD thesis]. Columbus: The Ohio State University; 2020.

41. Matiska P, Vejsadová H. Polyploidy induction in Phlox paniculata L. under in vitro conditions. Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis 2010; 58(1): 101–106. doi: 10.11118/actaun201058010101.

42. Roda F, Hopkins R. Correlated evolution of self and interspecific incompatibility across the range of a Texas wildflower. New Phytologist 2019; 221(1): 553–564. doi: 10.1111/nph.15340.