University of Tabriz Journal of Plant Physiology and Breeding 2008-5168 10 1 2020 06 01 Optimization of plant growth regulators for in vitro shoot proliferation of apple cv. ʽAbbasiʼ using response surface method کاربرد روش سطح پاسخ به‌منظور بهینه‌سازی غلظت تنظیم‌کننده‌های رشد برای پرآوری شاخساره سیب رقم ʼعباسیʽ در شرایط درون‌شیشه‌ای 111 125 12563 10.22034/jppb.2020.12563 EN Sajede Karimpour Department of Horticulture, Faculty of Agriculture, Ferdowsi University of Mashhad, Mashhad, Islamic Republic of Iran. Gholamhossein Davarynejad Department of Horticulture, Faculty of Agriculture, Ferdowsi University of Mashhad, Mashhad, Islamic Republic of Iran. Mohammad ZakiAghl Department of Plant Protection, Faculty of Agriculture, Ferdowsi University of Mashhad, Mashhad, Islamic Republic of Iran. Mohammad Reza Safarnejad Department of Plant viruses, Iranian Research Institute of Plant Protection, Agricultural Research Education and Extension Organization (AREEO), Tehran, Iran. Journal Article 2020 04 12 Optimization of medium components in <em>in vitro </em>cultures is very difficult because of having multifactor nature. To optimize the plant growth regulator concentrations (BA, IBA, GA₃) for shoot proliferation of apple cv. ‘Abbasi’ a three-factor experiment was designed and performed in 20 points (20 treatments) using Design Expert software based on the response surface method. A completely randomized design using eight auxin combinations (IBA+NAA) was also carried out for <em>in vitro</em> rooting of microcuttings. Proliferated shoot number was linearly and positively affected by the BA factor, while the response of the leaf number was linearly and negatively affected by BA. The effect of GA₃ on proliferated shoot length was negative and linear. The abnormal shoot percentage in a quadratic model was influenced by all three types of PGRs, i.e. BA, IBA and GA₃; positively and linear by BA, positively and quadratic by IBA and negatively and quadratic by GA₃. According to the results of this experiment, the optimum concentrations for BA, IBA and GA₃ combination were 1.5, 0.1 and 0.02 mg L^-1, respectively, which resulted in the proliferated shoots with a rate of 2.5 shoots per explant, with 0.9 cm in length, 4.3 leaves per shoot and 4% abnormal shoots. The percentage of shoot-tip necrosis was not affected by the evaluated factors. NAA was more effective than IBA for rooting microcutings. The medium supplemented by 1 mg L^-1 IBA or 0.5 mg L^-1 NAA can be used successfully for rooting of apple cv. ʽAbbasiʼ shoots <em>in vitro</em>. https://breeding.tabrizu.ac.ir/article_12563_9b51f61682a35b5d9d38f0fc13b3fa6b.pdf