تأثير همزيستي با گونه‌هاي قارچ ميكوريزا بر عملكرد، اجزاي عملكرد و كارايي مصرف آب كنجد (Sesamum indicum L.) تحت تأثير رژيم‌هاي مختلف آبياري در شرايط مشهد

Effect of Mycorrhiza Symbiosis on Yield, Yield Components and Water Use Efficiency of Sesame (Sesamum indicum L.) Affected by Different Irrigation Regimes in Mashhad Condition

به‌منظور بررسی تأثیر تلقیح با دو گونه قارچ میكوریزا بر عملكرد، اجزای عملكرد و كارایی مصرف آب گیاه دانه كنجد (Sesamum indicum L.)، آزمایشی در مزرعه تحقیقاتی دانشكده كشاورزی دانشگاه فردوسی مشهد در دو سال زراعی 89-1388 و 90-1389 به‌صورت اسپلیت پلات در قالب طرح بلوك‌های كامل تصادفی با سه تكرار انجام شد. كرت اصلی سه سطح آبیاری شامل 2000، 3000 و 4000 متر مكعب آبیاری در هكتار و كرت‌های فرعی تلقیح با دو گونه قارچ میكوریزا شامل Glomus mosseae و G. intraradices و شاهد بود. نتایج نشان داد كه اثر سطوح آبیاری بر تمام اجزای عملكرد به‌جز وزن هزار دانه، عملكرد بیولوژیك و دانه، شاخص برداشت و كارایی مصرف آب براساس عملكرد بیولوژیك و دانه معنی‌دار (05/0p≤) بود. با افزایش مقدار آبیاری از 2000 به 4000 متر مكعب در هكتار عملكرد بیولوژیك و دانه به‌ترتیب برابر با 52 و 118 درصد بهبود یافت. افزایش مقدار آبیاری از 2000 به 4000 متر مكعب در هكتار بهبود 22 درصدی كارایی مصرف آب كنجد براساس عملكرد دانه را موجب شد. تلقیح با گونه‌های میكوریزا اجزای عملكرد، عملكرد بیولوژیك و دانه، شاخص برداشت و كارایی مصرف آب كنجد براساس عملكرد بیولوژیك و دانه را به‌طور معنی‌داری تحت تأثیر قرار داد (05/0p≤). تلقیح باG. mosseae عملكرد دانه را به‌ترتیب برابر با 7 و 12 درصد در مقایسه با G. intraradices و شاهد بهبود بخشید. میزان این بهبود برای كارایی مصرف آب براساس عملكرد دانه به‌ترتیب برابر با 7 و 24 درصد بود. تلقیح با میكوریزا با بهبود توسعه سیستم ریشه‌ای و در نتیجه افزایش فراهمی رطوبت و دسترسی به عناصر غذایی موجب بهبود كارایی مصرف آب گردیده است كه این تأثیر برای گونه G. mosseae بالاتر از گونه G. intraradices بود.

Introduction Plant association with mycorrhiza has been considered as one of the options to improve input efficiency particularly for water and nutrient - (Allen and Musik, 1993; Bolan, 1991). This has been due to kncreasing the absorbing area of the root and therefore better contact with water and nutrients. Inoculation with mycorrhiza enhances nutrient uptake with low immobility such as phosphorus and solphur-, improve association and could be an option to drought and other environmental abnormalities such as salinity (Rice et al., 2002). Moreover, higher water use efficiency (WUE) for crops -has been reported in the literatures (Sekhara and Reddy, 1993).The sustainable use of scarce water resources in Iran is a priority for agricultural development. The pressure of using water in agriculture sector is increasing, so creating ways to improve water-use efficiency and taking a full advantage of available water are crucial. Water stress reduce crop yield by impairing the growth of crop canopy and biomass. Scheduling water application is very crucial for efficient use of drip irrigation system, as excessive irrigation reduces yield, while inadequate irrigation causes water stress and reduces production. The aim of present study was to evaluate the symbiotic effect of mycorrhiza on yield, yield components and water use efficiency of sesame under different irrigation regimes in Mashhad. Material and Methods In order to investigate the impact of inoculation with two species of Arbuscular mycorrhiza fungi on yield, yield components and water use efficiency (WUE) of sesame (Sesamum indicum L.) under different irrigation regimes, an experiment was conducted as split plot based on a randomized complete block design with three replications during two growing seasons 2009-2010 and 2010-2011 at the Agricultural Research Station, College of Agriculture, Ferdowsi University of Mashhad.. The experimental factors were three irrigation regimes include 2000, 3000 and 4000 m3 ha-1, inoculation with two species of mycorrhiza fungi (Glomus mosseae and G. intraradices) and control allocated to the main and sub plots, respectively. Results and Discussion Results showed that the effect of irrigation regimes were significant (p≤0.05) on yield components except 1000-seed weight, biological yield, seed yield, harvest index (HI) and WUE based on biological yield and seed yield. By increasing the irrigation level from 2000 to 4000 m3 ha-1 biological and seed yield enhanced up to 52% and 118%, respectively. Increasing the irrigation level from 2000 to 4000 m3 ha-1 also improved WUE based on seed yield up to 22%. Inoculation with mycorrhiza species had significant effect on yield components, biological yield, seed yield, HI and WUE based on biological yield and seed yield P ≤ 0.05). Inoculation with G. mosseae improved seed yield compared to G. intraradices and control with 7 and 12%, respectively. These improvement of WUE based on seed yield were 7% and 24%, respectively. In general, mycorrhiza inoculation enhanced WUE through root system development and nutrient availability as this effect for G. mosseae was higher than G. intraradices. Conclusions Yield and yield components of sesame were generally more responsive to irrigation level under mycorhiza inoculation. Sesame yield and its components were significantly affected by irrigation treatments. Increase the irrigation level enhanced biological and seed yield- and also improved WUE. The water was used more efficiently in the deficit irrigation treatments where WUE increased with lower amounts of water. Inoculation with G. mosseae improved seed yield compared to G. intraradices and control. Mycorrhiza inoculation enhanced WUE due to root system development and nutrient availability. These results highlight the importance of determining the interaction effects between water level and mycorrhiza inoculation on yield of sesame to formulate proper management practices for sustainable production.