اثر رژیم‌های آبیاری تنظیم‌شده بر ویژگی‌های رویشی، پومولوژیکی و عملکردی زیتون کنسروالیا در شرایط مزرعه

این پژوهش به ‌منظورشناخت مراحل حساس رشدی زیتون دربرابرتنش خشکی و ارزیابی اثر تنش کم‌آبی بر ویژگی‌های درخت زیتون رقم کنسروالیا در شرایط مزرعه در ایستگاه تحقیقات زیتون دالاهو طی سال زراعی 1395-1394 اجرا گردید. درختان 16 ساله زیتون رقم کنسروالیا تحت شش رژیم آبیاری قرار گرفتند.آزمایش در قالب طرح بلوک‌های کامل تصادفی با سه تکرار به انجام رسید. تیمارها شامل: آبیاری به میزان100 درصد نیاز آبی درختان (شاهد)، آبیاری 25 درصد در طول مدت سخت شدن هسته و 100 درصد در سایر مراحل رشد میوه، آبیاری به میزان 75 درصد از سخت شدن هسته تا برداشت محصول و 100 درصد در سایر مراحل رشد میوه، آبیاری فقط در سه مرحله قبل گل‌دهی، شروع سخت شدن هسته و یک هفته قبل از برداشت محصول، آبیاری به میزان 60 درصد نیاز آبی درختان زیتون طی کل فصل و شرایط دیم، بودند. پس از انجام تیمارها خصوصیات رویشی از جمله رشد و قطر شاخه سال جاری، خصوصیات میوه مانند وزن میوه، طول میوه، قطر میوه، وزن تر و خشک گوشت، درصد ماده خشک، درصد رطوبت میوه، درصد گوشت و نیز عملکرد و کارآیی مصرف آب اندازه‌گیری شد. نتایج نشان داد که آبیاری به میزان 25 درصد در طول مدت سخت شدن هسته باعث افزایش عملکرد میوه و روغن، ابعاد میوه و درصد گوشت شد و آبیاری در سه مرحله رشدی میوه و تیمار 60 درصد آبیاری از نظر ابعاد میوه، وزن تر گوشت، عملکرد میوه و روغن در هکتار برابر بودند.بازده مصرف آب در تیمار آبیاری در سه مرحله رشدی میوه و نیز کسر آبیاری در طول مدت سخت شدن هسته بالاتر از آبیاری کامل و دیگر تیمارها بود به‌طوری‌که میزان آن به‌ترتیب 14.30 و 4.29 کیلوگرم بر متر مکعب بود. به طور کلی نتایج نشان داد که کم آبیاری در مرحله سخت شدن هسته بدون تاثیر منفی بر عملکرد کل، سبب افزایش کارایی مصرف آب در زیتون رقم کنسروالیا می‌شود.

Effects of Regulated Deficit Irrigation Regime on Vegetative and Pomological Characteristics and Yield of Table Olive Konservolia Cultivar in Field Condition

Abstract   Background and Objectives Olive (Olea europaea L.) is one of the every green trees that tolerance to Drought. Olive is an economically important species of the Mediterranean area, so understanding the mechanisms by which olive plants face drought stress under environmental conditions is essential for the improvement of olive yield and oil quality. Olive (Olea europaea L.) is one of the fruit trees which become important in the Iranian fruit industry at the near future. It seems that olive tree has potential for resistance to drought conditions of semiarid regions of Iran. There is a high production potential for olive tree in many regions of Iran. Regulated deficit irrigation is an optimizing strategy under which crops are allowed to sustain some degree of water deficit and yield reduction. During regulated deficit irrigation the crop is exposed to certain level of water stress either during a particular period or throughout the growing season. The main objective deficit irrigation of is to increase water use efficiency (WUE) of the crop by eliminating irrigations that have little impact on yield, and to improve control of vegetative growth (improve fruit size and quality). The resulting yield reduction may be small compared with the benefits gained through diverting the saved water to irrigate other crops for which water would normally be insufficient under conventional irrigation practices. This study was aimed to investigate the effect of regulated deficit irrigation regime on vegetative and pomological characteristics and yield of table olive konservolia cultivar in field condition.   Materials and Methods This experiment was conducted in Dallaho Olive Research Station (Geographical characters was longitude of 45˚, 51΄ E and latitude of 34˚, 30΄ N and the height of sea level 581m) located in Kermanshah province. An experiment was used based on a randomized complete block design with three replications. Adult table olive Konservolia cultivar was uesd. Each experiment unit consists of Three trees. Vegetative and reproductive traits were evaluated according to I.O.O.C. descriptors. Six irrigation regimes including of full irrigation (as control), regulated deficit irrigation (100% of full irrigation during growing season plus 25% irrigation during pit hardening, regulated deficit irrigation (100% of full irrigation during growing season plus 75% irrigation from Start pit hardening to harvesting), irrigation in three stage (before flowering, pit hardening and before Harvesting , 60% of full irrigation (continuous deficit irrigation) and no irrigation (Rainfed). To elevate the effect of irrigation regimes, some growth vegetative traits measured at the end of growth season including currentseason shoot growth and currentseason shoot diameter as well as some fruit traits including fruit and oil yield, fruit weight, fruit length and diameter, pulp fresh and dry weight, fruit moisture percent, pulp percent were measured. Collected data were analyzed with SAS program.   Results Obtained results showed that the highest fruit yield, oil yield, fruit weight, fruit diameter, pulp fresh and dry weight, pulp percent were observed at full irrigation and regulated deficit irrigation (100% of full irrigation during growing season plus 25% irrigation during pit hardening, but the lowest one found at Rainfed. There was no significant difference between deficit irrigation in three stage and 60% of full irrigation (continuous deficit irrigation) in fruit yield, oil yield, fruit weight, fruit diameter, pulp fresh and dry weight. The water use efficiency of fruit yield of T4 and T2 was higher than 100ETc and other treatments. Overall, the results showed that RDI during fruit pit hardening could increased water use efficiency, whitout reduce fruit yield, oil yield, fruit weight, fruit diameter and pulp fresh and dry weight.   Discussion In the arid and semi arid as well as subtropical regions, water shortage is a normal phenomenon and seriously limits the agricultural potential.Therefore, under irrigation or rainfed conditions, it is important for the available water to be used in the most efficient way. Regulated deficit irrigation is an optimizing strategy under which crops are allowed to sustain some degree of water deficit and yield reduction. During regulated deficit irrigation the crop is exposed to certain level of water stress either during a particular period or throughout the growing season. The main objective deficit irrigation of is to increase water use efficiency (WUE) of the crop by eliminating irrigations that have little impact on yield, and to improve control of vegetative growth (improve fruit size and quality). According to the results of this research, it can be concluded thatthat RDI during fruit pit hardening could increased water use efficiency, whitout reduce fruit yield, oil yield, fruit weight, fruit diameter, pulp fresh and dry weight.