تولید گیاهان خودریشه گلابی رقم ʼنطنزʽ (pyrus communis l. cv. natanz) در شرایط درون‌شیشه‌ای

به منظور تولید درختان خودریشه گلابی رقم ʼنطنزʽ (pyrus communis cv. natanz) در شرایط درون شیشه‌ای سه آزمایش جداگانه برای بهبود پرآوری شاخه (تاثیرات bap و fe-naeddha)، استقرار مریستم (تاثیرات bap و ga3) و ریشه‌دهی ریزشاخه‌ها (تاثیرات iba و naa) در قالب طرح کاملاً تصادفی به اجرا در آمد. شاخه‌ها در محیط کشت pmi(ms ×1.5 cacl2. 2h2o, kh2po4 and mgso4. 7h2o) حاوی 1.5 میلی‌گرم بر لیتر bap و صفر میلی‌گرم بر لیتر fe-naeddha پرآوری شدند (5.50 شاخه/ریزنمونه) و رشد طولی خوبی داشتند در صورتی‌که غلظت‌های پایین bap و fe-naeddha برگ‌های بالغ بیشتری را تولید کرد. محیط کشت pmi غنی شده با 1 میلی‌گرم بر لیتر bap بعلاوه 150 میلی‌گرم بر لیتر fe-naeddha برای پرآوری شاخه نطنز بدلیل بالاترین میزان در رشد رویشی و بالاترین کیفیت شاخه‌های پرآوری شده پیشنهاد می‌شود. محیط کشت ms حاوی 0.5 میلی‌گرم بر لیتر bap و 0.5 میلی‌گرم بر لیتر ga3 و یا 1 میلی‌گرم بر لیتر bap (81 درصد) و 0.1 میلی‌گرم بر لیتر ga3 (63 درصد) به ترتیب بالاترین درصد استقرار مریستم را داشتند. ریزشاخه‌های درون شیشه‌ای نطنز از طریق فروبری سریع در محلول iba+naa (1000+1000 میلی‌گرم بر لیتر) و سپس قرار دادن در محیط کشت pmi ریشه‌دار شدند.

In Vitro Production of Own-Root Pyrus communis L. cv. Natanz

Introduction: Pyrus communis L. cv. Natanz is a popular pear cultivar in Iran because of its customerfriendly attribute due to its excellent characteristics. Pear ownrooted plants has better traits such as high vigorous in growth, low levels on tree losses and damaging by insects rather than grafted plants. Meristem culture widely used for micropropagation, in vitro germplasm preservation, and virus eradication purposes in pear. As pear is belonged to difficulttoroot fruit tree cultivars perhaps the rooting stage is the most important stage in propagation process, yet most difficult phase during the in vitro propagation procedure. In vitro rooting of microcuts was varied by genotypes (cultivars), type and concentration of auxin, the method of root induction and formation, different additional materials such as PVP, polyamines, and so on. This study was aimed to investigate the effect of different levels of BAP and FeEDDHA on shoot proliferation, BAP and GA3 on meristem establishment, and IBA and NAA on microcut rooting of pear cv. Natanz in in vitro condition.Materials and Methods: Vegetative buds were taken from current growth shoots of Pyrus communis cv. Natanz from Pear collection orchard (25.36 E, 58.54 N, and ASL altitude 1380 m) of Agricultural and Natural Resources Research and Education Centre of Semnan Province (Shahrood city). In the first experiment, new shoots of active buds after 4 weeks grown in PMI  medium (MS ×1.5 CaCl2. 2H2O, KH2PO4 and MgSO4. 7H2O) + 1 mg.l1 BAP were transferred to PMI  medium containing different levels of BAP (0.5, 1, 1.5 mg.l1) and FeEDDHA (0, 100, 150 and 200 mg.l1). In the second experiment, meristems (containing two newest leaf primordia) was excited from in vitro shoots and incubation on MS media containing BAP (0.5, 1, and 1.5 mg.l1) and GA3 (0.1 and 0.5 mg.l1) + 0.1 mg.l1 IBA. Meristems were kept in dark for 4 days then were transferred to growth chamber with photoperiod 16/8 hrs. light/dark. Different concentrations and combinations of two auxins were used for root induction of microcuts in third experiment. 1000, 2000, 3000, and 4000 mg.l1 of IBA or NAA and two combination solutions of them (1000 IBA+1000 NAA, and 2000 IBA+2000 NAA, mg.l1). Shoots were immersing dip in solutions for 5 seconds then transfer to PGRsfree PMI medium and kept them to growth chamber. Data of all experiments were analyzed according by completely randomized design (CRD) with five replications. BAP (3 levels) and FeEDDHA (4 levels) for experiment 1; BAP (3 levels) and GA3 (2 levels) for experiment 2 were considered as factorial. SAS (v. 9.1) was used for analysis and means were compared with LSD test at 5% of probability level.Results and Discussion: Proliferated shoot number was affected by BAP (p≤0.01) and FeEDDHA (p≤0.05) concentrations and also interaction of them (p≤0.05), while BAP (p≤0.01) was caused elongation of proliferated shoots and FeEDDHA had no effect. BAP (p≤0.05), FeEDDHA (p≤0.01) concentrations and BAP×FeEDDHA (p≤0.01) interaction had significant effect on leaf production. Shoot tip necrosis was shown in shoots grown in all media based on BAP concentration with different intensities (p≤0.05). Vegetative growth was counted as a power index of medium that in our experiment was under influence of BAP concentrations (p≤0.01), FeEDDHA (p≤0.05) and BAP×FeEDDHA interaction (p≤0.05). Shoots were proliferated (5.50 shoot.explant1) and elongated in PMI medium containing 1.5 mg.l1 BAP with no FeNaEDDHA while the lower concentrations of both BAP and FeNaEDDHA caused the higher mature leaf production. PMI media containing 1 mg.l1 BAP + 150 mg.l1 FeNaEDDHA is recommended for Natanz shoot proliferation because of the highest vegetative growth and highest quality in proliferated shoots. MS medium with 0.5 mg.l1 BAP+ 0.5 mg.l1 GA3 (81%) and 1 mg.l1 BAP + 0.1 mg.l1 GA3 (63%) had the highest meristem establishment, respectively. The established meristems naturally grown in medium supplement with 0.5 mg.l1 BAP + 0.5 mg.l1 GA3+0.1 mg.l1 IBA. Different types of auxin and their concentrations had significantly effect on Natanz pear cultivar microcut rooting (p≤0.05). NAA induced rooting in lower concentrations while IBA had positive effect on rooting with concentration increasing. Microcuts were rooted via quick dip in 1000+1000 mg.l1 (IBA+NAA) solution followed by incubation in PMI medium. The rooted shoots well adapted to environmental condition.Conclusion: Important steps of in vitro propagation of pear is optimized in this experiment. MS medium containing 0.5 mg.l1 BAP+0.5 mg.l1 GA3+0.1 mg.l1 IBA had suitable for meristem establishment. To produce in vitro healthy proliferated shoots of pear cv. Natanz using PMI medium supplement with 1 mg.l1 BAP+150 mg.l1 FeNaEDDHA is recommended. Microcuts were rooted easily by quick immersion of the end of microcuts in 1000+1000 mg.l1 (IBA+NAA) solution for 5 seconds then incubation in PGRsfree medium.