تأثير انبارداري پيوندك و زمان انجام پيوند بر گيرايي پيوند در ريزپيوندي برون شيشه‌اي پسته

Effect of scion storage and grafting time on graft unio‎n of Pistachio minigrafting under in-vivo condition

ريز پيوندي يكي از روش‌هاي نسبتاً جديد براي تكثير گياهان مي‌باشد. اين روش در گياهان چوبي به‌منظور توليد گياهان بدون بيماري، بازجوان‌سازي، بررسي موثر سازگاري پايه و پيوندك و افزايش غيرجنسي همسانه‌ها استفاده شده است. به‌منظور ارزيابي تأثير انبارداري پيوندك و زمان انجام پيوند بر گيرايي پيوند در ريزپيوندي برون‌شيشه‌اي پسته، آزمايش گلخانه‌اي با دو فاكتور شامل عامل زمان پيوند (بهمن، اسفند و ارديبهشت) و انبارداري پيوندك (صفر و 30 روز) با ده تكرار در قالب طرح كاملاً تصادفي طي سال‌هاي 1396 و 1397 و در گلخانه دانشگاه ولي عصر(عج) رفسنجان انجام شد. در اين آزمايش ميزان موفقيت ريزپيوندي پسته رقم "احمدآقايي" بر روي پايه‌هاي 14 روزه بادامي ريز زرند مورد آزمون قرار گرفت. پيوندك‌هاي "احمدآقايي" از سرشاخه‌هاي درختان بالغ در سه زمان مختلف (بهمن، اسفند و ارديبهشت) تهيه و بلافاصله يا پس از يك ماه انبارداري در دماي 4 درجه‌‌سلسيوس با روش اسكنه معكوس پيوند شدند. 21 روز پس از انجام عمل پيوند صفاتي همچون درصد گيرايي پيوند، رشد پيوندك، زمان لازم براي گيرايي، تعداد برگ پيوندك و ميزان قندهاي محلول كل پيوندك اندازه‌گيري شد. نتايج نشان داد كه بيشترين درصدگيرايي (100 درصد) و قندهاي محلول مربوط به زمان پيوند بهمن و با پيوندك‌هايي بود كه به‌صورت تازه برداشت و بلافاصله پيوند شدند. نتايج همچنين نشان داد بيشترين زمان لازم (18 روز) براي گيرايي پيوند در ارديبهشت با پيوندك‌هاي انبارشده به‌دست آمد. در مجموع نتايج اين پژوهش نشان مي‌دهدكه بهترين زمان براي انجام پيوند در بهمن ماه و با پيوندكي بود كه در همان زمان برداشت شده بود.

Background and Objectives Micrografting is a relatively new technique for propagation of plants. This technique has been used on woody species to produce viruses-free plants, rejuvenation, and reinvigoration, analysis of grafting compatibility and incompatibility and clone's propagation. Pistachio (Pistacia vera L.) is one of the most important commercial trees grown in arid and semi-arid regions of Iran where it is of vital importance to the permanent farming. Increase of pistachio cultivation areas during last three decades caused a continuous growing demand for pistachio planting materials in Iran. The benefits of applying in vivo and in vitro micrografting to the pistachio are obvious, especially when considering the need to improve the genetic quality of the planting stock of this slow-growing species while increasing crop potential. The objectives of this study were to determine the influence of scion storage and grafting time on clonal propagation of pistachio from elite-mature trees. Materials and methods In order to evaluate the effect of scion storage and grafting time on grafting success of in-vivo micrografting of Pistachio, an experiment was achieved an factorial based on compeletly randomized design (CRD) during 2017-2018 under greenhouse condition. In the experiment, the success of micrografting in "Ahmad aghaiee " Pistachio on 14-days "Badami-Riz-Zar@n" rootstocks were examined. The scion of "Ahmad aghaiee" were prepared from shoot tips of mature trees at three different times (February, march and may) and grafted immediately or after one month storage at 4 °C using inverted cleft grafting method. 21 days after grafting, some traits such as graft unio‎n percentage, scion growth, time to graft unio‎n, scion leaf number and total soluble sugar were recorded. Results The results showed that the highest graft unio‎n percentage (100%) was observed on the grafted plants of February, immediately after grafting. Based on the results, soluble sugars were significantly increased in freshly harvested scions in February and March. The results also showed that the maximum time (18 days) for time graft unio‎n was obtained in April with the stored scion whereas the lowest time graft unio‎n (11 days) was observed in February with scion taken at the same time. In addition, we found that the highest scion growth rate was due to freshly harvested scions and grafts in February. Discussion It was found that February was the best time of micrografting with scion taken at the same time because in this period carbohydrate content of the scions was higher than other months. Also, pistachio contain high amount of phenolic compounds. Exudation of phenolic compounds from the cut surfaces and their oxidation by polyphenoloxidase and peroxidase enzymes cause discoloration of the tissues which results in poor micrografting.