Document Type : Research paper


1 Crops and Horticultural Science Research Department, Kermanshah Agricultural and Natural Resources Research and Education Center, AREEO, Kermanshah, Iran.

2 Higher Education Institute of Jahad University of Kermanshah, Kermanshah, Iran.

3 Management of Agricultur jahad of Ravansar, Iran.


In order to evaluate the effect of plant growth regulators on sex determination and yield, an experiment was conducted by spraying different hormonal combinations on medicinal pumpkin. Experimental treatments were included different concentrations of NAA (25, 75, 100, 125 mg/l), paclobutrazol (50, 100, 200 and 300 mg/l) and combination of growth regulators (NAA 25 mg/l + PBZ 50 mg/l), (NAA 75 mg/l + PBZ 100 mg/l), (NAA 100 mg/l + PBZ 200 mg/l), (NAA 125 mg/l + PBZ 300 mg/l), and control (no application of growth regulators). Growth regulators were applied on the plants by spraying at the –two-leaf and four-leaf stages. Results showed that spraying paclobutrazol and NAA caused increase in number of female flowers, fruits per plant, seeds per fruits, 1000 seed weight and seed yield per hectare, but the number of male flowers and ratio of male to female flowers were decreased compared to their values in control plants. The highest fresh and dried seed yield of pumpkin seed was obtained with 50 mg/l paclobutrazol.


Abdollahi M, Eshghi S, Tafazzoli E, Moosavi N. 2012. Effects of Paclobutrazol, Boric Acid and Zinc Sulfate on Vegetative and Reproductive Growth of Strawberry cv. Selva. Journal of Agricultural Science and Technology 14, 357-363.
Al-Khassawaneh N.M, Karam N.S, Shibli R.A. 2006. Growth and flowering of black iris (Iris nigricans Dinsm.) following treatment with plant growth regulators. Scientia Horticulturae 107, 187-193.
Asin L, Alegre S, Montserrat R. 2007. Effect of paclobutrazol, prohexadione-Ca, deficit irrigation, summer pruning and root pruning on shoot growth, yield, and return bloom, in a ‘Blanquilla’ pear orchard. Scientia Horticulturae 113, 142-148.
Babadaei Samani R. 2014. Effects of paclobutrazol on vegetative and reproductive characteristics of peach (Prunus persica L.) cv. ‘Kardi’. Agricultural Communications 2(1), 37-42.
Bai D.I.S, Abraham A.T, Mercy S.T. 1987. Hormonal influence of crop performance in green gram. Legume Research 10(1), 49-52.
Banon S.A, Gonzalez E.A, Cano J.A, Franco J.A. 2002. Growth, development and color response of potted Dianthus caryophyllus cv. Mondriaan to paclobutrazol treatment. Scientia Horticulturae 94, 371-177.
Blaikie S.J, Kulkarni V.J, Muller W.J. 2004. Effects of morphactin and paclobutrazol flowering treatments on shoot and root phenology in mango cv. Kensington Pride. Scientia Horticulturae 101, 51-68.
Chibu H, Shibayama H, Mitsutomi M, Arima S. 2000. Effects of Chitosan application on growth and chitinase activity in several crops. Marine and Highland Bioscience Center Report 12, 27-35.
Cho M.H, No H.K, Prinyawiwatkul W. 2008. Chitosan treatments affect growth and selected quality of sunflower sprouts. Journal of Food Science 73, 570-577.
Dakua M.F. 2002. Effect of CI-IAA, TNZ-303 and GABA on growth, yield and yield contributing characters of lentil. M.S. Thesis, Department of Crop Botany, Bangladesh Agricultural University, Mymensingh.
.El-Zawily A.I, Arafa A.E.  1981. Effect of ethephon and indole-3-acetic acid on growth, flowering and fruiting of summer squash (Cucurbita pepo L.). Zagazig University, Research Bulletin 240, 1-2.
Gedam V.M, Patil R.B, Suryawanshi Y.B, Mate S.N. 1998. Effect of plant growth regulators and boron on flowering, fruiting and seed yield in bitter gourd. Seed Research 26, 97-100.
Ghosh A, Chikara J, Chaudhary D.R, Prakash A.R, Boricha G, Zala A. 2010. Paclobutrazol arrests vegetative growth and unveils unexpressed yield potential of Jatropha curcas. Journal of Plant Growth Regulation 29, 307-315.
Girek Z,  Prodanovic S, Zdravkovic J,  Zivanovic T, Ugrinovic M, Zdravkovic M. 2013. The effect of growth regulators on sex expression in melon (Cucumis melo L.).  Crop Breeding and Applied Biotechnology 13, 165-171.
Graebe J.E. 1987. The Annual Review of Plant Biology 38, 419-465.
Hayashi T.R, Cameron D.H, Carlson A.C. 2001. Ethephon influences flowering, height and branching of several herbaceous perennials. Scientia Horticulturae (91), 305-324.
Islam M.M. 2007. Effect of GABA on growth, yield and yield contributing characters of sesame. M.S. Thesis, Department of Crop Botany, Bangladesh Agricultural University, Mymensingh.
Jaleel C.A, Gopi R, Manivannan P, Sankar B, Kishorekumar A, Panneerselvam R. 2007. Antioxidant potentials and ajmalicine accumulation in Catharanthus roseus after treatment with gibberellic acid. Colloids and Surfaces B: Biointerfaces 60, 195-200.
Karaguzel O. 1999. The effects of paclobutrazole on growth and flowering of Bougainvillea spectabilis WİLLD. Turkish Journal of Agriculture and Forestry 23 (Supplement 2), 527- 532.
Kamountsis A.P, Chronopoulon-Sereli A.G. 1999. Horticultural Science 34, 674-675.
Khanzada A, Jamal M, Baloch M.S, Nawab K. 2002. Effect of naphthalein acetic acid (NAA) on yield of soybean. Pakistan Journal of Biological Sciences 3(5), 856-857.
Lee H.S. 1990. Effect of pre-sowing seed treatment with GA3 and IAA on flowering and yield components of groundnut. Korean Journal of Crop Science 35(1), 1-9.
Lerner R. 2003. Senior study vegetables—Squash. Horticulture and Landscape Architecture Department, Purdue University http://www.hort.purdue. edu/ext/senior/vegetabl/squash6..
Li S. (1979). Sex expression and chemical control in cucumber and pepo. Journal of Plant Physiology 15(1), 83-91.
Lolaei L, Mobasheri S, Bemana R,  Teymori1 N. 2013. Role of Paclobutrazol on Vegetative and Sexual Growth of Plants. International Journal of Agriculture and Crop Sciences 5 (9), 958-961.
Lolaei A, Rezaei M.A, Khorrami Raad M, Kaviani B. 2012. Effect of Paclobutrazol and Sulfate Zinc on Vegetative Growth, Yield and Fruit Quality of Strawberry (Fragaria × ananassa Duch. cv. Camarosa). Annals of Biological Research 3(10), 4657-4662.
Mancini L, Calabrese N. 1999. Effect of growth regulators on flower differentiation and yield in zucchini (Cucurbita pepo L.) grown in protected cultivation. Proceedings of the First International Symposium on Cucurbits 265.
Nasr M.N. 1995. Effects of methods of application and concentrations of paclobutrazol on Pelargonium zonale (L) as a pot plant. Alaxandria Journal of Agricultural Research 40(3), 261-279.
Ntui V.O, Uyoh E.A, Udensi O, Enok L.N. 2007. Response of pumpkin (Cucurbita ficifolia L.) to some growth regulators. Journal of Food, Agriculture and Environment 5(2), 211-214.
O’Donnell P.J, Calvert C, Atzorn R, Wasternack C, Leyser H.M.O, Bowles D.J. 1996. Ethylene as a signal mediating the wound Response of tomato plants. Science 274, 1914-1917.
O’Donnell P.J, Schmelz E, Block A, Miersch O, Wasternack C, Jones J.B, Klee H.J. 2003. Multiple hormones act sequentially to mediate a susceptible tomato pathogen defense response. Plant Physiology 133, 1181-1189.
Ouzounidou G, Papadopoulou P, Giannakoula A, Ilias I. 2008. Plant growth regulators treatments modulate growth, physiology and quality characteristics of Cucumis melo L. plants. Pakistan Journal of Botany 40(3), 1185-1193.
Papadopoulou E, Little H.A, Hammar S.A, Grumet R. 2005. Effect of modified endogenous ethylene production on sex expression, bisexual flower development and fruit production in melon (Cucumis melo L.). Sexual Plant Reprod. (18), 131-142.
Pen˜aranda A, Payan M.C, Garrido D, Go´mez P, Jamilena M. 2007. Production of fruits with attached flowers in zucchini squash is correlated with the arrest of maturation of female flowers. The Journal of Horticultural Science and Biotechnology 82(4), 579-584.
Pgrsa. 2007. Plant growth regulation handbook of the plant growth regulation Society of America. 4th Edition. The Plant Growth Regulation Society of America, Athens, GE, USA.
Rahman. 2006. Effect of gibberellic acid (GA3) on flowering and fruit development of bitter gourd. International Journal of Botany 2, 329-332.
Raoofi M.M, Dehghan S, Keighobadi M, poodineh O. 2014. Effect of naphthalene acetic acid in agriculture and the role of increase yield. International Journal of Agriculture and Crop Sciences 7 (14), 1378-1380.
Sedighi A, Davarinezhad GH, Azizi M, Arvin M.J. 2008. Effects of paclobutrazol application on vegetative and generative growth of ‘Lasjerdy’. Iranian Journal of Horticultural Science and Technology 9(3), 231-240.
Sedghi M, Gholipouri A, SHARIFI R.S. 2008. γ-Tocopherol Accumulation and Floral Differentiation of Medicinal Pumpkin (Cucurbıta pepo L.) in Response to Plant Growth Regulators. Notulae Botanicae Horti Agrobotanici Cluj-Napoca 36 (1), 80-84.
Senoo S, Isoda A. 2003. Effects of paclobutrazol on dry matter distribution and yield in peanut. Plant Production Science 6, 90-94.
Stepleton S.C, Wien H.C, Morse R.A. 2000. Flowering and fruit set of pumpkin cultivars under field conditions. HortScinece 35, 1074-1077.
Stevenson D.G, Eller F.J, Wang L, Jane J L, Wang T, Inglett G.E. 2007. Oil and tocopherol content and composition of pumpkin seed oil in 12 cultivars. Journal of Agricultural and Food Chemistry 55(10), 4005-4013.
Suty L. 1984.Growth regulator and potential of faba bean Cultivar 171, 71-73.
Tafazoli E, Beyl C. 1993. Changes in endogenous abscisic acid and cold hardiness in actinidia treated with triazole growth retardants. Plant Growth Regulation 12, 79-83.
Teppner H. 2000. Cucurbita pepo (cucurbitaceae)-history, seed coat types, thin coated seeds and their genetics. Phyton 40, 1-42.
Thappa M, Kumar S, Rafiq R. 2011. Influence of plant growth regulators on morphological, floral and yield traits of cucumber (cucumis sativus L.). Kasetsart Journal (Natural Science) (45), 177-188
Trebitsh T, Rudich J, Riov J. 1987. Auxin, biosynthesis of ethylene and sex expression in cucumber (Cucumis sativus). Plant Growth Regulation 5(2), 105-113.
Wang Q.M, Zeng G.W. 1997. Morphological and histochemical study on sex differentiation on Momordica charantia. Journal of Zhejiang Agriculture University, 23, 149-153.
Wang Q. 1997. Effect of chemical regulator and polyamine on sex differentiation in cucumber. Journal of Horticultur, 21(1), 48-52.
Watson G, Jacobs K. 2012. Control of apple scab and cytospora canker with paclobutrazol. Arboriculture & Urban Forestry 38(3), 112-116.
Ying Z. 1990. Relationship among sex expression, endogenous ethylene and activity of oxidizing enzyme in cucumber and pepo. Journal of Horticulture 17(1), 51-57.
Yu Y.B, Yang S. 1979. Auxin-induced ethylene production and its inhibition by aminoethoxy vinyiglycine and cobalt ion. Plant physiology 64, 1074-1077.