and chemical pinching OFA Bul. 896 21 24 Garner, J.M. Jones, S.A. Armitage, A.M. 1997 Pinch treatment and photoperiod influence flowering of Delphinium cultivars HortScience 32 61 63 Hunt, M.A. 1893 How to grow cut flowers. Moore and Langen, Terra
Jeffrey G. Norcini, William G. Hudson, Melvin P. Garber, Ronald K. Jones, Ann R. Chase, and Kane Bondari
Growers in the American Association of Nurserymen and the Society of American Florists were queried as to their use of plant growth regulators (PGRs) and nonchemical alternative practices during 1993. Daminozide (B-Nine SP) and chlormequat chloride (Cycocel) accounted for 78% of the total pounds active ingredient and were used by 20% and 17% of the respondents, respectively. In contrast, the rooting compounds indolebutyric acid (Dip `N Grow, Rootone, and Hormoroot) and naphthaleneacetic acid (Dip `N Grow, and Hormodin I, II, and III) were used by 53% and 24% of the respondents, respectively, but combined accounted for less than 3% of total pounds active ingredient. Pruning/pinching was used by the greatest number of respondents (82%) and was the only alternative to PGRs rated as very effective by more than 60% of the respondents. Use of chemical PGRs and nonchemical alternative practices was influenced by region and firm size. In the northeastern United States, growers reported relatively low use of PGRs (frequency and total pounds) and the lowest use of mechanical brushing as an alternative practice. In contrast, mechanical brushing was used most in the western United States. Large firms (more than $2 million in annual sales) reported the greatest use of chemical and nonchemical means of regulating growth.
Amir Rezazadeh, Richard L. Harkess, and Guihong Bi
et al., 2013 ), thereby chemical pinching has been used to enhance lateral branching. Application of PGRs is generally less labor intensive than hand pinching; however, PGRs may cause phytotoxicity ( Meijón et al., 2009 ). Plant growth regulators with
Amir Rezazadeh and Richard L. Harkess
is necessary to provide desirable marketable products. Numerous techniques have been used to control height and produce marketable plants. Pinching is the removal of the apical bud to overcome apical dominance and promote lateral branch development
Songul Sever Mutlu and Ece Agan
cultivation in Hokkaido Hokkaido Prefectural Agr. Expt. Sta. Res. Bul. 77 39 43 Vasudevan, S.N. Sudarshan, J.S. Kurdikerl, M.B. 2008 Influence of pinching of apical bud and chemical sprays on seed yield and quality of fenugreek Karnataka J. Agr. Sci. 21 26 29
Yin-Tung Wang and Thomas M. Blessington
Uniconazole and paclobutrazol were tested for their effects on greenhouse production of four foliage species. Soil drenches of uniconazole retarded shoot and petiole elongation of Brassaia actinophylla Endl. Paclobutrazol reduced shoot elongation, but required higher doses than uniconazole and did not reduce petiole growth. Foliar sprays with either retardant at 12.5 mg·liter-1 resulted in short stems on lateral shoots of Codiaeum variegatum (L.) Blume `Karen' after pinching, but soil drenches at low rates were less effective. Soil drenches of uniconazole or paclobutrazol were equally effective in reducing stem growth of Syngonium podophyllum Schott `White Butterfly' and increasing leaf width, but had no effect on the rate of leaf production or blade length. Both retardants induced short petioles in this species. Severe growth reduction occured on Plectranthus australis R. Br. even at the lowest rates of uniconazole and paclobutrazol (0.025 and 0.20 mg/pot, respectively) as soil drenches. Production of lateral shoots was inhibited for P. australis by both retardants. Chemical names used: (E)-1-(p-chlorophenyl)-4,4-dimethy1-2-(1,2,4-triazol-1-yl)-1-penten-3-ol (uniconazole); (2RS,3RS)-1-(4-chlorophenyl)-2-(1,1-dimethylethyl)-(H-1,2,4-triazol-l-Yl-)Dentan-3-ol (paclobutrazol).
Neil O. Anderson, Esther Gesick, Peter D. Ascher, Steven Poppe, Shengrui Yao, David Wildung, Patricia Johnson, Vincent Fritz, Charlie Rohwer, Lee Klossner, Neal Eash, Barbara E. Liedl, and Judith Reith-Rozelle
.7 to 17.8 cm with one/node initiated without removal of the apical meristem (pinching). Older stems have coloration of RHS yellow–green group 148A ( Anderson et al., 2003 ). Table 1. Comparative plant characteristics of Chrysanthemum × hybrida
A.P. Kamoutsis, A.G. Chronopoulou-Sereli, and E.A. Paspatis
The effects of several shading materials on the response of Gardenia jasminoides Ellis to paclobutrazol were investigated under greenhouse conditions. The three main plot treatments were shading (0%, 67%, 98%), and paclobutrazol (0.0, 0.5, 1.0, and 2 mg/pot) was applied as a soil drench in each main plot after pinching the plants. Both plant size and the number of flower buds per plant decreased as the rate of paclobutrazol increased at all levels of shading. The efficacy of paclobutrazol, however, was generally less under heavy shade, as both translocation of the growth retardant and photosynthesis were reduced. Moderate shading (67%) did not affect the size of plants receiving 0.0 or 0.5 mg of paclobutrazol per pot, but plants grown under heavy shade (98%) were 74% as large as similarly treated nonshaded plants. Medium shade reduced the size of plants receiving 1 and 2 mg paclobutrazol 4% and 6%, respectively, relative to that of similarly treated nonshaded plants, whereas heavy shade reduced plant size 11%. The number of flower buds per plant was reduced 30% by moderate shading, 90% by heavy shading. Significant quadratic relationships were observed between the rate of paclobutrazol applied and (1) plant size, and (2) the number of flower buds per plant. Chemical name used: ±-(R * ,R *)-β–[(4-chlorophenyl)methyl]-α-(1,1-dimethyl)-1H-(1,2,4-triazol)-1-ethanol (paclobutrazol).
Aristidis S. Matsoukis, Ioannis Tsiros, and Athanasios Kamoutsis
The effect of various plant growth regulators on leaf area development of Lantana camara L. subsp. camara was investigated under three photosynthetic photon flux (PPF) conditions (100%, 72%, and 34% light transmittance). The triazole compounds paclobutrazol (0, 50, 100, 200, and 500 mg·L-1) and triapenthenol (175, 350, 700, and 1400 mg·L-1), as well as the onium-type compounds mepiquat chloride (125, 250, 500, and 1000 mg·L-1) and chlormequat chloride (750, 1500, 3000, and 6000 mg·L-1), were applied as foliar spray solutions in each PPF level after pinching the plants. Leaf area, in general, decreased logarithmically as the concentrations of paclobutrazol and triapenthenol increased at all PPF levels. On the other hand, PPF reduction was found to increase leaf area of lantana plants treated with all concentrations of each regulator. Leaf area reduction of the paclobutrazol and triapenthenol treated plants at all PPF levels exceeded 60% compared with that of nontreated plants. However, the corresponding reduction was 22%, up to 51% for the plants treated with mepiquat chloride and chlormequat chloride. These results indicate that the triazole compounds have a greater effect on the reduction of lantana leaf area than the onium-type compounds. Chemical names used: (2RS, 3RS)-1-(4-chlorophenyl)-4, 4-dimethyl-2-(1H-1, 2, 4-triazol-1-yl) pentan-3-ol (paclobutrazol); (E)-(RS)-1-cyclohexyl-4,4-dimethyl-2-(1H-1, 2, 4-triazol-1-yl) pent-1-en-1-ol (triapenthenol); 1,1-dimethyl-piperidinium chloride (mepiquat chloride); (2-chloroethyl) trimethylammonium chloride (chlormequat chloride).
Bruce L. Dunn, Stephen Stanphill, and Carla Goad
included pinching (leaving seven nodes), no pinching, no pinching plus Atrimmec (PBI-Gordon Corporation, KS City, MO) with rates of 3.9, 7.8, 11.7, and 23.4 mL⋅L −1 using tap water, and pinching with similar rates and conditions mentioned. Chemical