www.scholarsresearchlibrary.com t Available online a Scholars Research Library Annals of Biological Research, 2012, 3 (10):4663-4667 (http://scholarsresearchlibrary.com/archive.html) ISSN 0976-1233 CODEN (USA): ABRNBW 4663 Scholars Research Library Effect of Paclobutrazol and Salinity on Vegetative and Sexual Growth and Fruit Quality of Strawberry (Fragaria × Ananassa Duch. cv. Selva) Abolfazl Lolaei 1 , Behzad Kaviani 2* , Mojtaba Korrami Raad 3 , Mohammad Ali Rezaei 4 and Matin Maghsoudi 3 1 Young Researchers Club, Gorgon Branch, Islamic Azad University, Gorgon, Iran 2 Department of Horticultural Science, Rasht Branch, Islamic Azad University, Rasht, Iran 3 Department of Tissue Culture, Branch of North Region of Iran (Rasht), Agricultural Biotechnology Research Institute of Iran (ABRII) 4 Department of Biology, Gorgan Branch, Islamic Azad University, Gorgan, Iran _____________________________________________________________________________________________ ABSTRACT Paclobutrazol (PBZ) and sodium chloride (NaCl) were sprayed on strawberry (Fragaria × Ananassa Duch. cv. Selva). The experiment was carried out in a factorial randomized complete block design with three replications in greenhouse conditions. Plants were treated with two levels of NaCl (0 and 20 mg L -1 ) and four levels of PBZ (0, 30, 60 and 90 mg L -1 ). Results showed that PBZ is an important factor for increasing the generative traits and fruit quality, but not on vegetative traits. The highest leaf number, leaf area, petiole length, and total soluble solid (T.S.S.) percent were observed in control plants, while highest fruit number, fruit weight, fruit set, flower number and yield of strawberry were obtained in plants treated with 90 mg L -1 PBZ. Foliar application of PBZ prior to flowering is recommended to increase the yield of strawberry. Key words: fruit set, salinity, strawberry, paclobutrazol, yield _____________________________________________________________________________________________ INTRODUCTION The cultivated strawberry is a hybrid plant crossed between two species, Fragaria chiloensis and Fragaria virginiana. The botanical name of the common cultivated strawberry is Fragaria × ananassa. Since 1850 hundreds varieties have been selected and named. Several cultivated forms of strawberry can be grouped as June bearing, overbearing and day-neutral [21]. Triazole compounds are new synthetic plant growth regulators that act as anti gibberellins and known to inhibit shoot growth in plants [12]. Include the increased antioxidant potentials, inhibition of plant growth, decreased inter- node elongation, increased chlorophyll levels, thicker leaf tissue and increased root to shoot ratio [37]. Triazoles affect the isoprenoid pathway and alter the levels of certain plant hormones by inhibiting gibberellins synthesis, increasing cytokinin levels and reducing ethylene evolution [25]. Paclobutrazol (PBZ) is a potent inhibitor of gibberellins biosynthesis by inhibiting the oxidation of ent-kaurene to ent-kaurenoic acid through inactivating cytochrome P450-dependent oxygenases [19]. Triazoles, also stimulate the accumulation of ABA in the leaves [2]. PBZ can be applied as an overall spray, as a soil drench or by way of trunk painting; better results have been