تاثير رژيم آبياري بر برخي ويژگيهاي رويشي نهالهاي توليدي گونه تادار در مبداهاي جغرافيايي متفاوت

The effect of irrigation regime on vegetative characteristics of Caucasian hackberry (Celtis caucasica) seedlings in diverse provenance

سابقه و هدف: هدف از اين تحقيق، تاثير رژيم آبياري بر رشد نهال هاي توليدي تادار (Celtis caucasica willd.) در مبدأهاي جغرافيايي كرج، همدان، خرم آباد، و شيراز است. مواد و روش‌ها: بعد از جمع آوري بذور جهت مطالعه ي اثر تيمارهاي آبياري و مبدأ بذر، اقدام به كاشت بذور در گلدان‌هاي پلي‌اتيلن شد. تا قبل از جوانه زني بذور، همه ي گلدان ها داراي شرايط يكسان بودند. پس از آن، به مدت شش ماه از اوايل خرداد تا اواخر آبان ماه تحت چهار تيمار آبياري شاهد، سه روزه، پنج روزه و هشت روزه در سه تكرار 30 تايي قرار گرفتند. در انتهاي فصل رويش، ارتفاع نهال، قطر يقه، سطح برگ، طول ريشه، طول ساقه و درصد زنده‌ماني نهال ها اندازه گيري شد. يافته‌ها: نتايج آزمون توكي نشان داد اثر مبدأ بذر بر تمام صفات اندازه گيري شده معني دار مي‌باشد (P<0.05). تيمار آبياري به طور معني داري بر ارتفاع نهال، قطر يقه و مساحت برگ تاثير داشت(P<0.05). به طور ميانگين، بيش ترين مقدار پارامترهاي اندازه گيري شده در مبدأ بذر كرج و كم ترين، در مبدأ همدان بود. به طور متوسط، درصد زنده ماني نهال ها در تمام رژيم هاي آبياري 70 درصد به دست آمد و بيش ترين درصد زنده ماني متعلق به تيمار شاهد بود. بيش ترين مقدار رويش نهال ها در تيمار شاهد و كم ترين در تيمار پنج و هشت روزه مشاهده شد. نتيجه‌گيري: پيشنهاد مي شود براي جنگل كاري در كرج، از بذرهاي مبدأ كرج استفاده شود. همچنين، با توجه به اين كه تفاوت چشمگيري در رويش نهال ها در تيمارهاي آبياري مشاهده نشد، از تيمار آبياري هشت روزه با توجه به مقرون به صرفه تر بودن اين رژيم، استفاده شود.

Background and Objectives: One of the issues that plays an important role in selecting the suitable seeds for plantation projects is the seed provenance effect test. Production of suitable seedlings in terms of quantitative and qualitative values mostly depends on edaphic and climatic conditions of seed origin place and planting location. The purpose of this research was to examine the effect of irrigation regime on the characteristics of Celtis caucasica seedlings collected from Karaj, Hamedan, Khorramabad, and Shiraz provenance. Materials and Methods: In order to find the most suitable irrigation treatment and to investigate different provenances of Celtis caucasica seedlings the needed seeds were collected from forests and mountains of Alborz, Fars, Hamedan and Lorestan. After collecting the seeds were planted in the polyethylene pots. All the pots had the same circumstances before seeds germination. Finally, 30 seedlings were used in four irrigation treatments including 1, 3, 5 and 8-day irrigation in three replicates for six months from early June to late November. The seedlings height, collar diameter, leaf area, root length, stem length, and seedling survival percentage at the end of the growing season were measured. Results: Tukey test results showed that the effect of seed provenance on all measured traits was significant (P<0.05). Irrigation treatments significantly affected seedling height, collar diameter, root length, leaf area and survival on various provenance (P<0.05). On average, the highest amount of measured parameters was for the Karaj provenance while the lowest was for Hamadan provenance. Also, the highest leaf area was related to irrigation treatment of Karaj and Khorramabad provenance. Commonly, the seedling survival in all irrigation regimes were 66.25% but the highest survival rate was related to control treatment (71%). The highest seedling growth was observed in control treatment, while the least in 5-days treatment. Conclusion: based on the results, the seeds of dry regions were able to withstand drought stress in 8-day irrigation and had more growth than other regions. Using Karaj seeds for afforestation in Karaj is highly recommended. Since no significant difference was found among different irrigation treatments therefore it is suggested to apply an 8-day irrigation period for reducing the seedlings production cost in the nursery.