فهرست مطالب

  • سال هفدهم شماره 1 (پیاپی 63، 1398)
  • تاریخ انتشار: 1397/12/26
  • تعداد عناوین: 12
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  • علیرضا برجسته، احمد نظامی، حمیدرضا خزاعی، اسکندر زند صفحات 1-14
    با توجه به محدودیت منابع آب و تاثیر منفی کمبود آب و رقابت علف های هرز بر عملکرد گندم، بررسی خصوصیات گیاه گندم تحت تاثیر کمبود آب و رقابت علف هرز از اهمیت خاصی برخوردار است. آزمایش مزرعه ای به صورت کرت های خرد شده در قالب طرح بلوک کامل تصادفی به منظور بررسی تاثیر کم آبیاری (سه رژیم آبیاری مشتمل بر تامین 100، 80 و 60 درصد نیاز آبی گندم به عنوان عامل اصلی) و تراکم علف هرز یولاف وحشی (چهار تراکم یولاف شامل تراکم صفر، 20، 40 و 80 بوته در متر مربع به عنوان عامل فرعی) در مرکز تحقیقات کشاورزی استان سمنان (شاهرود) انجام شد. نتایج نشان داد که اثر کم آبیاری و افزایش تراکم یولاف بر تعداد سنبله، تعداد دانه در سنبله، وزن هزار دانه، طول سنبله، ارتفاع بوته، عملکرد دانه، عملکرد بیولوژیک، شاخص برداشت و بهره وری آب معنی دار بود. کاهش میزان آب مصرفی به 60 درصد نیاز آبی به ترتیب کاهش 59/38 و 64/11 درصدی عملکرد دانه و بیولوژیک گندم در تراکم 80 بوته یولاف در متر مربع را به دنبال داشت. افزایش تراکم یولاف تا 20 بوته در متر مربع تاثیر معنی داری بر عملکرد دانه و بیولوژیک گندم نداشت در حالی که افزایش تراکم به 80 بوته در متر مربع در رژیم کم آبیاری تامین 60 درصد نیاز آبی موجب کاهش 3/52 و 2/26 درصدی عملکرد دانه و بیولوژیک نسبت به شاهد (100% نیاز آبی) و تراکم صفر یولاف شد. تعداد سنبله در واحد سطح همبستگی مثبت و معنی داری (r=0.97 **) با عملکرد داشت. همچنین نتایج نشان داد که کم آبیاری به میزان تامین 80 درصد نیازآبی گندم علی رغم کاهش 9 درصدی عملکرد دانه با صرفه جویی 12 درصدی آب موجب افزایش 6/4 درصدی بهره وری آب (نسبت عملکرد دانه به آب مصرفی) نسبت به شرایط مطلوب رطوبتی شد در حالی که با کاهش میزان آب آبیاری به 60 درصد نیاز آبی، بهره وری آب نسبت به شرایط مطلوب رطوبتی 6/13 درصد کاهش یافت. آزمایش حاضر نشان داد که امکان دارد کاهش میزان آب به 80 درصد نیاز آبی در شرایط محدودیت منابع آبی بتواند ضمن صرفه جویی در مصرف آب به ثبات تولید نیز در این شرایط کمک نماید.
    کلیدواژگان: ارتفاع، بهره وری آب، تعداد سنبله، تنش خشکی، علف هرز
  • علیرضا کوچکی، مهدی نصیری محلاتی صفحات 15-38
    در این تحقیق عملکرد پتانسیل و خلاء عملکرد گندم آبی و چغندرقند در استان خراسان رضوی طی دوره ای 10 ساله (1393-1384) مورد بررسی قرار گرفته است. به این منظور بر اساس داده های درازمدت هواشناسی 17 شهرستان و با استفاده از آنالیز خوشه ایسه ناحیه اقلیمی کشاورزی در استان خراسان رضوی از یکدیگر تفکیک شدند. پیش بینی عملکرد پتانسیل با استفاده از مدل شبیه سازی LINTUL1 انجام شد و پیش از استفاده از آن بر مبنای داده های عملکرد در معرض تعیین اعتبار متقابل قرار گرفت. بر اساس نتایج شبیه سازی، عملکرد پتانسیل (YP) گندم آبی در نواحی اقلیمی کشاورزی 1 (نیمه خشک و معتدل)، 2 (خشک و گرم) و 3 (نیمه خشک و گرم) به ترتیب 7248، 6478 و 7852 و درکل استان 6936 کیلوگرم در هکتار برآورد شد. در حدود 74 درصد از تغییرات سالانه YP گندم آبی ناشی از تغییر در طول دوره پر شدن دانه به دلیل افزایش درجه حرارت می باشد. خلاء عملکرد گندم آبی در هر سه ناحیه در طی 5 سال ابتدای دوره به طور نسبی افزایش یافته و به حدود 4 تن در هکتار رسید ولی از سال 1390 خلاء عملکرد در حال کاهش بوده به طوری که میزان خلاء قابل مهار آن در سال 93 بین 50/0-48/0 عملکرد پتانسیل بوده است. میانگین عملکرد پتانسیل گندم دیم در نواحی اقلیمی بین 2800-2000 کیلوگرم در هکتار برآورد شد و بر این اساس میانگین خلاء نسبی استان در محدوده 8/0-75/0 به دست آمد. میانگین 10 ساله عملکرد پتانسیل چغندرقند در نواحی اقلیمی استان خراسان رضوی بین t ha-1 88-78 پیش بینی شد.
    کلیدواژگان: اطلس جهانی خلاء عملکرد، عملکرد پتانسیل، خلاء قابل مهار، تعیین اعتبار متقابل
  • فاطمه عباس پور، حمیدرضا اصغری، پرویز رضوانی مقدم، حمید عباسدخت، جواد شباهنگ، عادل بیگ بابایی صفحات 39-52
    به منظور بررسی تاثیر بیوچار بر حاصلخیزی خاک و کارایی مصرف آب در سیاه دانه (Nigella sativa L.) در شرایط تنش خشکی، آزمایشی به صورت اسپلیت پلات فاکتوریل در قالب طرح بلوک های کامل تصادفی با سه تکرار در سال زراعی 95-1394در مزرعه تحقیقاتی دانشکده کشاورزی دانشگاه فردوسی مشهد اجرا گردید. تیمارها شامل آبیاری به عنوان عامل اصلی در سه سطح 100درصد، 70 و 40درصد نیاز آبی و کرت های فرعی شامل فاکتور بیوچار در سه سطح شامل بدون بیوچار، 10 تن در هکتار بیوچار و 20 تن در هکتار بیوچار و کود شیمیایی در دو سطح شامل بدون مصرف کود و مصرف کود بود. نتایج نشان داد که مصرف20 تن در هکتار بیوچار بیشترین تاثیر را بر درصد نیتروژن خاک، میزان پتاسیم، درصد مواد آلی و کربن زیست توده میکروبی خاک داشت ولی اثر بیوچار بر میزان فسفر قابل دسترس خاک معنی دار نبود. نتایج مرتبط با گیاه سیاه دانه نشان داد که با وجود معنی دار نبودن اثر ساده بیوچار بر صفات گیاه، اثر متقابل آن با کود شیمیایی و نیاز آبی معنی دار شد. بیشترین کارایی مصرف آب بر اساس عملکرد دانه در تیمارهای آبیاری بر اساس 70 درصد نیاز آبی به همراه مصرف کود شیمیایی (I2F2) و 10 تن در هکتار بیوچار به همراه مصرف کود شیمیایی (B2F2) مشاهده شد. اثرات متقابل آبیاری، بیوچار و کود شیمیایی تاثیر معنی داری بر عملکرد دانه و عملکرد کاه و کلش در سیاه دانه داشت و بیشترین تاثیر مربوط به تیمار آبیاری بر اساس 70 درصد نیاز آبی به همراه 10 تن در هکتار بیوچار و کودشیمیایی (I2B2F2) بود. به طور کلی، استفاده از بیوچار در مناطق خشک و نیمه خشک علاوه بر بهبود خصوصیات خاک، جذب آب و عناصر غذایی توسط گیاه را افزایش داده و با تاثیر بهینه بر عملکرد، میزان آب مصرفی در سیاه دانه را کاهش داده و باعث صرفه جویی در مصرف آب می شود.
    کلیدواژگان: کربن زیست توده میکروبی، کود شیمیایی، عملکرد دانه، مواد آلی خاک
  • عباس فروغی آینه ده، عباس بیابانی، علی راحمی کاریزکی، قربانعلی رسام صفحات 53-73
    به منظور مطالعه تغییرات خصوصیات فیزیولوژیک ارقام و لاین های کلزا و اثرات این تغییرات بر بهبود پتانسیل عملکرد، آزمایشی طی سال های زراعی 94-1393 و 95-1394 در مجتمع آموزش عالی شیروان، خراسان شمالی انجام شد. در این آزمایش 20 رقم و لاین کلزا در قالب طرح بلوک های کامل تصادفی با چهار تکرار آزمایش شدند. به منظور بررسی شاخص های رشد، ارقام بر اساس تجزیه کلاستر به سه گروه با عملکرد بالا (Bilbao)، متوسط (کرج 3) و پایین (ساری گل) تقسیم شدند و از هر گروه یک نماینده انتخاب شد. ارقام از لحاظ خصوصیات فنولوژیک متنوع بودند به طوری که ارقامی نظیر ساری گل، طلایه، شیرالی، ظفر و زرفام زودتر از سایر ارقام به مرحله رسیدگی فیزیولوژیک رسیدند. همبستگی مثبت و معنی دار دوام گل دهی با عملکرد (**66/0=r) و تعداد خورجین در بوته (**88/0=r) از اهمیت این دوره در تعیین عملکرد دانه دارد.از نظر شاخص سطح برگ، رقم Bilbao نسبت به دو رقم کرج 3 و ساری گل برتری داشت. همچنین رقم ساری گل زودتر از دو رقم دیگر به حداکثر شاخص سطح برگ رسید. همبستگی قوی بین حداکثر تجمع ماده ی خشک و عملکرد دانه وجود داشت (**81/0=r). شاخص های رشد از جمله CGR و RGR در سال اول به طور معنی داری از سال دوم بیش تر بودند. مقدار ضریب خاموشی (K) در سال اول از 65/0 (شیرالی) تا 77/0 (ظفر و ساری گل) و در سال دوم از 63/0 (کرج 3) تا 80/0 (ظفر) متغیر بود. متوسط کارایی مصرف نور به ترتیب در دو سال آزمایش 80/3 و 63/3 گرم بر مگاژول در متر مربع برآورد گردید. به طور کلی عملکرد دانه در سال اول بیش تر از سال دوم انجام آزمایش بود. میانگین عملکرد ارقام در سال اول 80/453 گرم در متر مربع و در سال دوم 84/401 گرم در متر مربع بود. بیش ترین عملکرد در سال نخست انجام آزمایش متعلق به ارقام Bilbao، Kodiak، SW102، GKH-305 و Traviata با میانگین عملکرد 55/495 گرم در متر مربع و کم ترین عملکرد متعلق به ارقام زرفام، ساری گل، طلایه، شیرالی و Modena با میانگین عملکرد 48/370 گرم در متر مربع بود. بیش ترین عملکرد در سال دوم انجام آزمایش متعلق به ارقام Bilbao، GKH-305، Slm046، L72، SW102، Kodiak و Traviata با میانگین عملکرد 31/450 گرم در متر مربع و کم ترین میزان عملکرد متعلق به ارقام طلایه، Opera، کرج3، Okapi، Modena، GKH-2005 و کرج 1 با میانگین عملکرد 66/349 گرم در متر مربع بود. به طور کلی ارقامی که شاخص سطح برگ بالاتری داشتند و نیز زمان رسیدن به شاخص سطح برگ حداکثر، همزمان با تشعشع دریافتی بیش تر بود و هم چنین از تشعشع دریافتی با کارایی بالاتر بهره مند شدند، عملکرد بالاتری داشتند.
    کلیدواژگان: خصوصیات فنولوژی، شاخص سطح برگ، ضریب خاموشی، کارایی مصرف نور
  • داود صادق زاده اهری صفحات 75-82
    در این مطالعه تحمل به یخ زدگی 33 ژنوتیپ نخود موجود در آزمایش های مقایسه عملکرد پیشرفته مناطق سردسیر دیم و سه ژنوتیپ شاهد (سارال، ILC 533 و جم) در اتاقک سرما و در قالب طرح لاتیس مربع با دو تکرار بررسی شد. کشت در هفتم مهر ماه انجام و تا مرحله شش هفتگی در بیرون از گلخانه نگهداری و تعداد بذرهای سبز شده آنها یادداشت گردید. گیاهچه ها به مدت یک ساعت در معرض سرمای 15- درجه سانتی گراد قرار گرفته و سپس به مدت سه روز به اطاقک رشد (دمای 4+ درجه سانتی گراد) منتقل شدند. گیاهان در شرایط گلخانه به مدت دو هفته و در دمای 3±20 درجه سانتی گراد نگهداری و تعداد گیاه چه های باقیمانده ژنوتیپ ها ثبت شد. نتایج نشان داد که تفاوت معنی داری بین ژنوتیپ ها از نظر نسبت مقاومت به یخ زدگی وجود داشت. لاین های شماره 14( (Flip98-138C*SEL99TER85074)*SEL99TH15039)، 28(FLIP 00-84 C) و رقم سارال به ترتیب با 100، 98 و 89 درصد بقاء دارای بیشترین تحمل به یخ زدگی بودند. رقم نخود کاکا و لاین شماره 12((Flip 98-28C*Flip 98-22C)* ICCV2) با میزان بقای پنج درصد دارای کمترین تحمل در برابر یخ زدگی بودند. جمع بندی نتایج ضمن تایید وجود منابع ژنتیکی متحمل به سرما در ژرم پلاسم مورد مطالعه، نشان داد که امکان دسترسی به ژنوتیپ هایی با تحمل به سرمای بیشتر از رقم سارال به عنوان اولین رقم متحمل به یخبندان، جهت کشت پاییزه در مناطق سردسیر دیم وجود دارد.
    کلیدواژگان: رقم سارال، دیم، گیاه چه، لاین، نسبت مقاومت به یخ زدگی
  • رحیم ناصری، مهرشاد براری، محمد جواد زارع، کاظم خاوازی، زهرا طهماسبی صفحات 83-98
    به منظور بررسی اثر تلقیح با باکتری سودوموناس و قارچ میکوریزا بر سیستم ریشه دهی و عملکرد دانه ارقام گندم در شرایط دیم، آزمایشی مزرعه ای به صورت فاکتوریل در قالب طرح بلوک های کامل تصادفی با سه تکرار در دو مزرعه در دانشکده کشاورزی، دانشگاه ایلام و ایستگاه تحقیقات کشاورزی سرابله در سال زراعی 93-1392 اجرا شد. تیمارهای آزمایشی شامل عامل رقم گندم در دو سطح (کراس سبلان و ساجی) و تیمار منابع کودی در هشت سطح شامل: 1- شاهد (عدم مصرف هیچ منبع کودی)، 2- 50 کیلوگرم در هکتار کود شیمیایی فسفر، 3- باکتری سودوموناس پوتیدا،
    4- قارچ گلوموس موسه آ، 5- باکتری سودوموناس پوتیدا+ قارچ گلوموس موسه آ، 6- باکتری سودوموناس پوتیدا+ قارچ گلوموس موسه آ+25 کیلوگرم در هکتار کود شیمیایی فسفر، 7- باکتری سودوموناس پوتیدا+25 کیلوگرم در هکتار کود شیمیایی فسفر و 8- قارچ گلوموس موسه آ+25 کیلوگرم در هکتار کود شیمیایی فسفر بودند. نتایج این پژوهش نشان داد که برهمکنش رقم×منابع کودی بر عملکرد، اجزای عملکرد دانه و همچنین خصوصیات ریشه ای گندم دیم معنی دار بود. به طوری که بیشترین تعداد سنبله در مترمربع (افزایش 7/16 درصدی)، تعداد دانه در سنبله (افزایش 2/67 درصدی)، وزن هزار دانه (افزایش 3/19 درصدی)، عملکرد دانه (افزایش 72 درصدی)، عملکرد زیست توده (افزایش 57 درصدی)، حجم ریشه (افزایش 6/53 درصدی)، سطح ریشه (افزایش 3/69 درصدی)، تراکم طول ریشه (افزایش 5/76 درصدی) و چگالی سطح ریشه (افزایش 69 درصدی) در رقم ساجی× قارچ گلوموس موسه آ+25 کیلوگرم در هکتار کود شیمیایی فسفر نسبت به شاهد (عدم مصرف هیچ منبع کودی) به دست آمد. نتایج این تحقیق نشان داد که در شرایط کشت گندم دیم در ایلام که گیاه با تنش های آخر فصلی (خشکی و دما) مواجه می گردد، گندم دوروم دیم رقم ساجی و تلقیح با قارچ میکوریزا به دلیل بهبود سیستم ریشه دهی در شرایط دیم نتیجه مطلوب تری از خود نشان داده و موجب افزایش عملکرد دانه می گردد.
    کلیدواژگان: حجم ریشه، سطح ریشه، سیستم ریشه، عملکرد دانه، منابع کودی
  • بهرام مسعودی صفحات 99-110
    جهت مشخص کردن روابط بین عملکرد دانه و درصد روغن با برخی از صفات مهم زراعی و پیدا کردن اثرات مستقیم و غیر مستقیم آنها روی عملکرد دانه و درصد روغن و نیز انتخاب بهترین ارقام از نظر صفات مختلف، 91 ژنوتیپ کنجد در یک طرح آگمنت در موسسه اصلاح و تهیه نهال و بذر کرج در سال 1395 مطالعه شدند. در این مطالعه 17 صفت کمی از جمله تعداد روز از جوانه زنی تا شروع گلدهی، تعداد روز از جوانه زنی تا شروع رسیدگی، ارتفاع اولین کپسول از سطح زمین، ارتفاع بوته، تعداد شاخه فرعی، تعداد کپسول در شاخه های فرعی، تعداد کپسول در شاخه اصلی، تعداد کپسول های یک بوته، تعداد دانه در یک کپسول، وزن دانه یک کپسول، وزن صد دانه، وزن یک کپسول، طول کپسول، قطر کپسول، درصد روغن، عملکرد بیولوژیک و عملکرد دانه مورد ارزیابی قرار گرفت. ضرایب همبستگی ساده محاسبه گردید و معلوم شد که تعداد کپسول ها در گیاه، تعداد کپسول در شاخه های فرعی، عملکرد بیولوژیک، تعداد کپسول در شاخه اصلی و ارتفاع گیاه بالاترین ضرایب همبستگی را با عملکرد دانه دارا هستند. همچنین وزن صد دانه، عملکرد دانه تک بوته، تعداد کپسول در شاخه اصلی، تعداد کپسول در تک بوته و وزن دانه های یک کپسول بالاترین همبستگی را با درصد روغن داشتند. تجزیه علیت نشان داد که تعداد کپسول ها در بوته، تعداد کپسول ها در شاخه فرعی، عملکرد بیولوژیک و طول کپسول بیشترین اثر مستقیم مثبت را روی عملکرد دانه دارا بودند و پیشنهاد می شود که به عنوان شاخص های انتخاب برای پیشرفت عملکرد دانه به کار روند. همچنین وزن دانه های یک کپسول، طول کپسول، عملکرد دانه و تعداد کپسول در شاخه اصلی به ترتیب دارای بالاترین اثرات مستقیم مثبت روی درصد روغن دانه بودند. نتایج تجزیه به مولفه های اصلی نشان داد که 6 مولفه مجموعا 77/82 درصد از تغییرات داده ها را توجیه کردند. از لحاظ عملکرد به ترتیب ژنوتیپ های Lao hong zhi ma، Black c-2-c، Dulce 101/87 و Bukbak دارای بالاترین عملکرد دانه در بین ژنوتیپ های مورد بررسی در بای پلات حاصل از مولفه اول و دوم بودند. ژنوتیپ شماره 79 با نام White c323-2 دارای عملکرد نسبی خوب و همچنین مقدار روغن دانه نسبتا خوب است. علاوه بر این، ژنوتیپ های شماره 79 و 51، با نام های White c323-2 و Local 123 دارای عملکرد نسبی خوب و نیز نسبتا زودرس است. در نهایت، ژنوتیپ شماره 49 با نام Lao hong zhi ma، دارای عملکرد نسبی بالا و تعداد دانه در هر کپسول بالا می باشد. با توجه به نتایج می توان نتیجه گیری کرد که در اصلاح برای هر مولفه باید به صفات مرتبط با آن مولفه توجه شود به این دلیل که ژن یا ژن هایی که تعداد کپسول در یک بوته را کنترل می کنند، وزن یک بوته، وزن یک کپسول و صفات دیگر معنی دار در این مولفه را نیز به احتمال خیلی زیاد کنترل می کنند و مولفه یا ژنی که این صفات را کنترل می کند، مولفه یا ژن مشترک می باشد.
    کلیدواژگان: تجزیه به مولفه ها، تجزیه علیت، درصد روغن، عملکرد دانه
  • وحید بحرینی ویجویه، محمدرضا داداشی، سیدمحمود ناظری صفحات 111-121
    این بررسی به منظور تعیین حدود حساسیت و تحمل به تنش کمبود رطوبتی ژنوتیپ های گندم به شرایط آبیاری کامل و کمبود رطوبتی در دوره زایشی اجرا شد. تعداد هشت ژنوتیپ حاصل از برنامه به نژادی اقلیم سرد کشور که دارای تیپ رشد زمستانه در مقایسه با ارقام اروم، میهن و زارع به عنوان شاهد بر پایه طرح بلوک کامل تصادفی با سه تکرار طی دو سال زراعی 1395-1393 در دو شرایط آبیاری کامل و کمبود رطوبتی در دوره زایشی در ایستگاه تحقیقات کشاورزی طرق مشهد مورد مقایسه قرار گرفتند. در این تحقیق از 14 شاخص ارزیابی تنش به ترتیب شاخص حساسیت به تنش (SSI)، شاخص تحمل به تنش (STI)، شاخص تحمل (TOL)، شاخص بهره وری متوسط (MP)، شاخص میانگین هندسی بهره وری (GMP)، میانگین هارمونیک (HM)، شاخص تحمل به تنش تعدیل یافته (MSTI)، شاخص پایداری عملکرد (YSI)، شاخص عملکرد (YI)، شاخص خشکی (DI)، شاخص تحمل غیرزیستی، (ATI) شاخص درصد حساسیت به تنش (SSPI)، شاخص محصول در تنش و بدون تنش (SNPI) و درصد کاهش عملکرد (RE) استفاده گردید. در مجموع شاخص ها پنج شاخص میانگین هندسی بهره وری (GMP)، تحمل به تنش (STI)، میانگین بهره وری (MP)، میانگین هارمونیک (HM) و شاخص تحمل به تنش تعدیل یافته (MSTI) با احتمال 99 درصد بیشترین همبستگی را با عملکرد دانه در شرایط بدون تنش و تنش نشان دادند و به عنوان برترین شاخص های متحمل به خشکی در این بررسی مشخص شدند. ژنوتیپ هشت که بالاترین مقدار را در این پنج شاخص داشت به عنوان متحمل ترین ژنوتیپ در شرایط تنش شناسایی گردید. ارقام شاهد به لحاظ عملکرد و تحمل به تنش خشکی در قیاس با ژنوتیپ هشت جایگاه مناسبی نداشتند. در شرایط تنش خشکی ژنوتیپ هشت بیشترین عملکرد را با 5176 کیلوگرم در هکتار به خود اختصاص داده و در رتبه میانگین شاخص های این تحقیق رتبه اول را داشت. ژنوتیپ 9 نیز از لحاظ عملکرد دانه در شرایط تنش خشکی با 5079 کیلوگرم در هکتار و رتبه دوم در میانگین شاخص های این تحقیق به عنوان بهترین ژنوتیپ متحمل به خشکی بعد از ژنوتیپ 8 قرار گرفت.
    کلیدواژگان: بهره وری، پایداری، شاخص عملکرد، کمبود رطوبت
  • خدیجه علیزاده، اسماعیل رضایی چیانه، رضا امیرنیا، محسن برین صفحات 123-140
    به منظور بررسی اثر کودهای زیستی بر برخی ویژگی های زراعی بزرک (Linum usitatissimum L.) و باقلا (Vicia faba L.) در کشت مخلوط، آزمایشی به صورت فاکتوریل در قالب طرح بلوک های کامل تصادفی با سه تکرار در مزرعه تحقیقاتی دانشکده کشاورزی دانشگاه ارومیه در سال زراعی 96-1395 به اجرا درآمد. عامل اول شامل الگوی کشت در پنج سطح شامل کشت خالص بزرک، کشت خالص باقلا، کشت مخلوط یک ردیف بزرک + یک ردیف باقلا، دو ردیف بزرک + دو ردیف باقلا و سه ردیف بزرک + سه ردیف باقلا و عامل دوم شامل عدم مصرف و مصرف کود زیستی (ترکیب قارچ میکوریزا+ باکتری های تامین کننده نیتروژن، فسفر، پتاسیم و گوگرد) بود. صفات مورد مطالعه برای بزرک شامل ارتفاع بوته، تعداد شاخه های جانبی، تعداد کپسول در بوته، تعداد دانه در کپسول، وزن هزار دانه، عملکرد دانه، عملکرد بیولوژیک و درصد روغن و برای باقلا شامل ارتفاع بوته، تعداد شاخه های جانبی، طول نیام، تعداد نیام در بوته، تعداد دانه در نیام، وزن هزار دانه، عملکرد بیولوژیک و عملکرد دانه بودند. نتایج نشان داد که الگوی کشت بر کلیه صفات مورد بررسی باقلا و بزرک اثر معنی دار داشت. حداکثر عملکرد دانه و عملکرد بیولوژیک باقلا به ترتیب از کشت خالص (به ترتیب با 280/4 و 300/13 تن در هکتار) و کمترین مقادیر آنها از کشت مخلوط با نسبت یک ردیف بزرک و یک ردیف باقلا خالص (به ترتیب با 590/2 و 240/10 تن در هکتار) به دست آمد. حداکثر عملکرد دانه و عملکرد بیولوژیک بزرک از کشت خالص بزرک (به ترتیب با 230/2 و 153/7 تن در هکتار) و کمترین میزان عملکرد از کشت مخلوط سه ردیف بزرک و سه ردیف باقلا (به ترتیب با 040/1 و 992/4 تن در هکتار) حاصل شد. درصد روغن بزرک در تمامی الگوهای کشت مخلوط بیشتر از کشت خالص بود. همچنین، بالاترین عملکرد دانه و عملکرد بیولوژیک هر دو گونه در شرایط کاربرد کود زیستی و کمترین مقادیر عملکرد دانه و عملکرد بیولوژیک از عدم مصرف کاربرد کود زیستی به دست آمد. بالاترین نسبت برابری زمین نیز در شرایط کاربرد کود زیستی در کشت مخلوط دو ردیف بزرک + دو ردیف باقلا برابر با 53/1 به دست آمد که معادل 53 درصد افزایش در بهره وری استفاده از زمین نسبت به کشت خالص دو گونه بود و این نشان دهنده برتری کشت مخلوط در مقایسه با کشت خالص است.
    کلیدواژگان: ازتوباکتر، الگوی کشت، باکتری های حل کننده فسفات، روغن، نسبت برابری زمین
  • امیرعباس رستمی اجیرلو، محمدرضا اصغری پور، احمد قنبری، مهدی جودی، محمود خرمی وفا صفحات 141-155
    در این پژوهش با استفاده از مدل AquaCrop عملکرد دانه، زیست توده و طول دوره رشد سه هیبرید ذرت تحت شرایط اقلیم آینده، در تیمارهای مختلف آبیاری شبیه سازی شد. به این منظور، از داده های بارش، دمای کمینه، دمای بیشینه و ساعت آفتابی مدل ریز مقیاس نمایی LARS-WG با استفاده از مدل گردش عمومی جوHadCM3 برای سه سناریو گزارش چهارم هیات تغییر اقلیم (A1B، A2 و B1) پیش بینی و برای دشت مغان در دوره های 2010-1970، 2030-2011 و 2065-2046 مورد بررسی قرار گرفت. مدل AquaCrop قبل از استفاده، توسط داده های مزرعه ای (سال های 1394 و 1395) واسنجی و تعیین اعتبار شد. سپس طول دوره رشد هیبریدها، مقادیر عملکرد دانه و زیست توده در دوره های آینده، برای تیمارهای متفاوت آبیاری (I1= آبیاری نرمال، I2= قطع آبیاری در مرحله رشد رویشی، I3= قطع آبیاری در مرحله گل دهی و I4= قطع آبیاری در مرحله پر شدن دانه) و هیبریدهای متفاوت ذرت (C1= SC704، C2= SC703 و C3= SC705) شبیه سازی شد. با توجه به نتایج، در دوره آماری 2030-2011 میلادی در مقایسه با دوره 2010-1970 (پایه) میانگین ماهانه دمای به مقدار 41/1، 35/1 و 56/1 درجه سانتی گراد به ترتیب در سناریوهای A1B، A2 و B1 افزایش، میانگین ماهانه بارش به مقدار 6، 11 و 15 میلی متر به ترتیب در سناریوهای A1B، A2 و B1 کاهش خواهد یافت و در دوره آماری 2065-2046 میلادی در مقایسه با دوره پایه میانگین ماهانه دمای به مقدار 9/2، 69/2 و 32/2 درجه سانتی گراد، به ترتیب در سناریوهای A1B، A2 و B1 افزایش خواهد یافت. همچنین در طی این دوره، مقدار کاهش بارندگی به مقدار 18، 15 و 14میلی متر به ترتیب در سناریوهای A1B، A2 و B1 پیش بینی شد. نتایج شبیه سازی عملکرد دانه و زیست توده کل ارقام ذرت تحت تاثیر مدیریت های آبیاری با استفاده از مدل AquaCrop، نشان داد که متغیرهای آماری ریشه میانگین مربعات خطای عملکرد دانه و ماده خشک در سال های 1394 و 1395، به ترتیب 413 و 891 کیلوگرم در هکتار بود. مقدار ریشه میانگین مربعات خطای نرمال شده عملکرد دانه و ماده خشک، به ترتیب 11 و 10 درصد به دست آمد. به علاوه، استفاده از داده های هواشناسی آینده تحت سناریوهای مختلف تغییر اقلیم نشان از کاهش طول دوره رشد، عملکرد دانه و عملکرد زیست توده در دوره های 2030-2011 و 2065-2046 در سناریوهای A1B، A2 و B1 دارد. در بین ارقام مورد مطالعه در این تحقیق مشاهده شد که هیبرید سینگل کراس 704 نسبت به سایر هیبریدهای ذرت دارای کاهش رشد و عملکرد کمتری می باشد. بنابراین این رقم می تواند برای تغییر اقلیم آینده در دشت مغان مناسب باشد.
    کلیدواژگان: آب و هوا، بحران آب، تنش خشکی، مدل AquaCrop
  • عباس ابهری، اسماعیل قلی نژاد صفحات 157-167
    به منظور بررسی تاثیر سالیسیلیک اسید بر کارآیی مصرف آب و برخی خصوصیات فیزیولوژیکی جو در شرایط تنش خشکی، آزمایشی در سال زراعی 1396 به صورت فاکتوریل در قالب طرح پایه بلوک های کامل تصادفی با سه تکرار در مزارع کیذور واقع در شهرستان سبزوار انجام شد. تیمارها شامل آبیاری در دو سطح قطع آبیاری (قطع آبیاری از مرحله آبستنی (کد 49 زادوکس) تا برداشت) و آبیاری کامل و تیمار محلول پاشی سالیسیلیک اسید در چهار سطح صفر (شاهد)، دو، چهار و شش میلی مولار در مرحله ساقه دهی (کد 39 زادوکس) روی جو اجرا شد. نتایج نشان داد که در هر دو شرایط آبیاری کامل و قطع آبیاری بیشترین تعداد سنبله، تعداد دانه در سنبله، عملکرد دانه و عملکرد بیولوژیکی در متر مربع به ترتیب در تیمار محلول پاشی دو تا شش میلی مولار سالسیلیک اسید و کمترین آن مربوط به تیمار شاهد بود. کمترین کارایی مصرف آب (38/0) در شرایط قطع آبیاری و بدون مصرف سالیسیلیک اسید حاصل شد و با مصرف سالیسیلیک اسید تا شش میلی مولار کارایی مصرف آب افزایش یافت. همچنین با افزایش مصرف سالیسیلیک اسید در شرایط قطع آبیاری در مقایسه با آبیاری کامل، کارایی مصرف آب افزایش بیشتری یافت. کمبود آب از یک طرف با تاثیر بر ساختار غشای سلول سبب افزایش نفوذپذیری غشا نسبت به یون ها و ماکرو مولکول ها شد (نشت الکترولیت برگ در شرایط آبیاری کامل و قطع آبیاری به‎ترتیب 45/0 و 58/0 بود) و از طرف دیگر، با افت شاخص کلروفیل، فتوسنتز را کاهش داد که در نهایت کاهش عملکرد و اجزای آن را به همراه داشت. از طرفی، اسید سالیسیلیک موجب تعدیل تنش خشکی از طریق کاهش نشت یونی (عدم مصرف و مصرف سالسیلیک اسید شش میلی مولار در شرایط قطع آبیاری به ‎ترتیب 61/0 و 38/0 بود)، افزایش غلظت پرولین و شاخص کلروفیل در نتیجه بهبود عملکرد دانه گندم در شرایط قطع آبیاری در مقایسه با آبیاری کامل گردید.
    کلیدواژگان: پرولین، شاخص کلروفیل، عملکرد دانه، قطع آبیاری، نشت الکترولیت
  • سید فرهاد صابرعلی، حسین نستری نصرآبادی، محمد دوستخواه احمدی صفحات 169-186
    کشاورزی، که عامل تامین نیاز غذایی و ثبات اقتصادی و امنیتی هر جامعه ای است، می تواند تحت تاثیر نوسانات اقلیمی هر منطقه قرار گیرد. بررسی تاثیر اقلیم بر تولید محصولات زراعی همچون گندم که یک محصول راهبردی در تامین امنیت غذایی جامعه ایرانی است از اهمیت دوچندانی برخوردار است. هدف از این مطالعه پیش بینی اثرات تغیر اقلیم در آینده نزدیک بر عملکرد گندم آبی در منطقه تربت جام با بیشترین سطح زیر کشت در استان خراسان رضوی بود. در این تحقیق از برنامه MarkSim تحت چهار سناریوی انتشار RCP2.6، RCP4.5، RCP6 و RCP8.5 برای تولید داده های اقلیمی در دوره آینده نزدیک (2047-2018) استفاده شد. در نهایت داده های اقلیمی خروجی از برنامه MarkSim به عنوان داده های آب و هوایی ورودی برای اجرای مدل شبیه سازی رشد گیاهان زراعی DSSAT مورد استفاده قرار گرفت. نتایج شبیه سازی رشد گندم آبی در دوره پایه نشان داد که این گیاه کاهش دوره رشد و افزایش تولید ماده خشک و عملکرد را در دوره 20 ساله اخیر تجربه کرده است. افزایش بارش های بهاری و همچنین افزایش دما در طول فصول سرد سال ازجمله دلایل این افزایش بوده است. همچنین افزایش دما در طول فصل سرد سال و افزایش غلظت دی اکسید کربن در آینده نزدیک تحت سناریوهای مختلف تغییر اقلیم افزایش حدود 20 تا 25 درصدی تولید دانه گندم را باعث خواهند شد. اگرچه میزان این افزایش تولید در خاک های سبک تر کمتر از خاک های سنگین تر منطقه بود. همچنین مشخص گردید، با وجود احتمال کاهش حداقل 300 متر مکعب آب آبیاری در هر هکتار در طول دوره رشد گندم در 30 سال آینده، در نهایت با به کار گیری سیستم های آبیاری با راندمان بالاتر احتمالا افزایش تولید با تغییرات چندانی روبه رو نخواهد شد.
    کلیدواژگان: افزایش دما، سناریوی انتشار، شبیه سازی، DSSAT، MarkSim
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  • A. R. Barjasteh, A. Nezami*, H. R. Khazaei, E. Zand Pages 1-14
    Introduction
    Water stress is one of the most important abiotic factors that restrict the growth and production of plants in the world, especially in arid and semi-arid regions. In Iran, a majority of wheat are located in arid and semi-arid regions. In these regions, drought stress occurs due to the lack of water which causes a considerable decrease in the yield of wheat. A suitable strategy to achieve satisfactory production in these areas is to apply deficient irrigation systems with the aim of improving water use efficiency and acceptable yield. Weed competition is another factor which decreases the wheat yield. Wild oat, due to its high compatibility and different ecological conditions, is one of the most important weed in wheat in most areas of Iran. Therefore, it is necessary to understand their behavior in the field, if we plan to apply appropriate weed management methods. Because any management change in the field may change weed behavior, and since the drip irrigation is spreading and the merits of deficit irrigation is known, it is necessary to evaluate their behavior at these conditions. Thus, the aim of this study was to study the wheat response to the interference of wild oat under deficit irrigation conditions.
    Materials and Methods
    An experiment as split plot in randomized complete block design was conducted to evaluate the effects of deficit irrigation in three levels (supply of 100, 80 and 60 percent of crop water requirement as main plot) and wild oat density in four levels (0, 20, 40 and 80 plant m-2) on wheat yield in Shahrood agricultural research center. Wild oat seed was collected from wheat field around Shahrood and was planted with wheat. Crop water requirements calculated by Penman-Monteith equation amended by FAO. Irrigation treatments was applied at the beginning of jointing stage and continued during the growing season. At the end of experiment, two square meters of each plot harvested to measure the grain yield and biological yield. At this time 0.25 square meters of each plot harvested and yield components were measured. Data were analyzed in SAS software (version 9.1). Slicing method was used for interaction mean comparison.
    Results and Discussion
    The effects of irrigation regime and wild oat density were significant on the number of spikes, the number of grains at spike, infertile tiller ratio, spike length, plant height, biological yield, grain yield, harvest index and water productivity. Decreasing the water usage to 60% of the water requirement decreased the grain yield and biological yield of wheat by 38.59 and 11.64%, respectively at the density of 80 bushes m2. Increasing the wild oat density up to 20 plants per m2 had no significant effect on the grain and biological yield of wheat, while increasing it up to 80 plants in the deficient irrigation regime with 60% of water requirement, decreased the grain and biological yield of wheat to 52.3 and 26.2%, respectively, compared with the control (100% of the water requirement) and zero density of wild oat treatment. Spike numbers per unit area showed a significant and positive correlation (r=0.97**) with yield. Moreover, the results showed that deficient irrigation regime with supplying 80% of the water requirement reduced the grain yield and water usage by 9 and 12%, respectively and it improved the water productivity by 4.6% compared with the optimum water conditions. Whereas, reducing the amount of irrigation water to 60% of the required water, decreased the water productivity by 13.6% compared with the optimum water conditions.
    Conclusions
    Results showed that the deficit irrigation decreases the yield and yield components. Reducing water usage to 80% of water requirement reduced the water usage to 12%, consequently, although the water productivity increased, the yield decreased by 9%. Thus, it could be a suitable approach for regions with low water reservoirs. In the other words, in low water regions, the best choice to manage optimum irrigation to achieve constant production and increasing usable water is “the lower water-the higher productivity” strategy. Increasing wild oat density up to 20 plants m-2 had no significant effect on the grain and biological yield of wheat. However, increasing wild oat density up to 80 plants m2 decreased these properties under all irrigation regimes. The insensitivity of wheat to wild oat competition in lower densities is due to the growth characteristics and competitive ability of Alvand variety.
    Keywords: Drought stress, Height, Number of spike, Water productivity, Weed
  • A Koocheki, M Nassiri Mahallati Pages 15-38
    Introduction
    To realize global food demand by 2050 world cereal production should be increased up to 49% compared to 2006. This level of production could be achieved by annual yield increment of 1.16%. However, the current rates are much lower. At the same time, there is a very restricted area to increase cultivated lands because of resource limitation, provided that increase in crop yields is the main option to sustain food security. Potential yield (YP) could be achieved when limiting and reducing factors are completely absent during crop growth. YP is an indicator for the yielding capacity of a given environment and management system and estimating the difference between YP and actual yield, known as yield gap, is crucial for improvement of crop production systems at regional or national scale. In this study yield gap and its temporal trend for sugar beet, irrigated and rainfed wheat are estimated over Khorasan Razavi province based on the method developed by Global Yield Gap Atlas.
    Materials and Methods
    Following the protocol provided by Global Yield Gap Atlas, Khorasan province was clustered into agroclimatic zones using the proposed indices (cumulative degree days above 0 ºC, aridity index and temperature seasonality) based on 10 years (1384-1393) weather data. YP of sugar beet and irrigated wheat for the study period in the climatic regions was first estimated for selected cities within each region using LINTUL model and finally the simulation results were up scaled from cities to region and from regions to the whole province. The model was cross-validated against measured data using leave-one-out (LOO) method to increase accuracy of predictions. Potential yield of rainfed wheat (YW) was estimated from frontier production function which was fitted to yield data over a wide range of annual precipitation. Yield gap (YG) of the studied crops was estimated as the difference between potential (YP) and actual yields (YA) for each region and over the 10-year period. In addition exploitable gap (YG85%=85%YP-YA) was also calculated.
    Results and Discussion
    The accuracy of LINTUL model for simulation of sugar beet and irrigated wheat yields was considerably increased after cross validation and the prediction error was reduced by 6.5 - 7.8%. Mean YP of irrigated wheat in the climatic region 1 (temperate, semi-dry), 2 (hot, dry) and 3 (temperate, dry) was respectively, 7248, 6478 and 7852 and for the whole province 6936 kg ha-1. Time trend of YP for irrigated wheat was not significant in 3 climatic regions however, high annual variation of YP was found over the studied period. Results indicated that up to 74% of this variation was accounted for by changes in the effective grain filling period in response to temperature. YG85% of irrigated wheat in all climatic regions was increased up to 4 t ha-1 during 1384-1388 but decreased later on so that relative gap was 0.48-0.50 of YP in 1993. Average YW of rainfed wheat in the climatic regions of the province was estimated as 2000-2800 kg ha-1 with a negative trend due to decreased precipitation, the highest negative slope in YW (59 kg ha-1 y-1) was found in the hot dry region. Rainfed wheat showed an extremely high yield gap in all climatic regions and mean relative yield gap (YG/YW) was estimated as 0.75-0.80 over the province. Mean YP of sugar beet in different climatic regions of the province was estimated from 78 to 88 t ha-1 with the lowest potential in hot-dry region. However, declining trend was found in the yield gap of sugar beet in all studied regions with the highest gap filling rate of 1.44 t ha-1 y-1 in temperate-dry region.
    Conclusions
    Simulated YP of sugar beet and irrigated wheat were higher in temperate-semi arid regions of the province and lower in hot-dry regions. However, cold-semi arid regions had the highest YW of rainfed wheat. When up-scaled over the province, YG85% was about 50% of YP for irrigated wheat and sugar beet and 25% for rainfed wheat. It was concluded that closing yield gap of sugar beet and irrigated wheat would be possible mainly by improving management practices however, for rainfed wheat breeding strategies should be considered as the first priority.
    Keywords: Cross validation, Exploitable yield gap, Global yield gap atlas, Potential yield
  • F AbbaspourShahrood, H. R AsghariShahrood, P Rezvani Moghaddam, H AbbasdokhtShahrood, J Shabahang, A Baig Babaei Pages 39-52
    Introduction
    Application of chemical fertilizers since green revolution, make the crop production doubled or even tripled in some crops. However, long-term overuse of these fertilizers decreased soil quality. Thus to obtain the same yield, the rate of inorganic fertilizer application steadily increases from year to year. Recent studies revealed that in order to increase the chemical fertilizer efficiency, it needed to integrate organic resources with chemical fertilizers to soil. However, using organic manure in the soil will be decomposed very rapidly. Biochar is a source of high organic carbon which highly resistant to decomposition. It has a porous quality and large surface area which reduces leaching of nutrients. Biochar addition to soils can change microbial biomass, adsorb toxic compounds and improved soil water and pH status. The internal porosity of biochars may help soil microorganisms avoid grazers. Globally demands for plant- based medicines are growing. Black seed (Nigella sativa L.) is annual plant to Ranunculaceae family, is grown in arid and semi-arid regions of the world. Black seed considered as a spice, medicinal plant and used as seasoning in cooking and foodstuffs. Recently, there has been an increasing interest in integrated approaches in improving crop production to resist conditions of nutrient-poor soil, drought, and salinization. Since, a few attempt has been made to investigate the effects of biochar amendment on medicinal plants in semi-arid agricultural systems, the present study was initiated in agro ecological condition of Mashhad.
    Materials and Methods
    A field experiment was conducted as split plots factorial layout based on a randomized complete block design with three factors and three replications at the Research Station, Faculty of Agriculture, Ferdowsi University of Mashhad, Iran during growing season of 2016. Three levels of irrigation (100, 70, and 40 percent of water irrigation requirement) were assigned as main plots and the combination of three levels of biochar (0, 10, and 20 ton ha-1) and two levels of chemical fertilizers (without and with chemical fertilizer) were allocated as sub plots. Recommended dose for nitrogen, phosphorus, and potassium was 150 kg ha-1, 75 kg ha-1 and 100 kg ha-1, respectively. The size of each experimental unit was 3×2 m2. Black seed thinning was performed after emergence to get a plant population density of 200 plants m-2. Post experimental soil which was amended with biochar and fertilizer were analyzed for total nitrogen, available phosphorus, potassium, soil organic matter, and microbial biomass carbon. Plant criteria which studied were such as grain yield (kg ha-1), straw yield (kg.ha-1) and water use efficiency (base of grain yield). Analysis of Variance (ANOVA) and Duncan multiple range test were used to compare the recoded data.
    Results and Discussion
    Soil N, K, SOM, and Microbial biomass carbon were significantly affected by biochar application. Phosphorus was not affected by biochar. The highest biochar effect on soil characteristics was found under 20 ton ha-1 biochar application treatment. The results showed that application of 10 and 20 ton ha-1 of biochar improved soil nitrogen compared with control treatment. Soil organic matter was increased by 1.56% compared with 1.33% in control when 20 ton ha-1 biochar was used. It has been reported that the biochar may increase the organic matter of the poor soils. The soil microbial biomass carbon was increased by biochar and fertilizer application. It seems that the reason for increasing soil microbial biomass by adding biochar to the soil is enhancing available soil nutrients, adsorption of toxic compounds and improved soil water and pH status. The internal porosity of biochars may help soil microorganisms avoid grazers. Combine use of fertilizer and biochar were more affected on plants growth than biochar or fertilizer alone. The interaction between biochar, chemical fertilizer and water requirements significantly affected the seed and straw yield. The significant increase of grain yield, straw yield observed in I2B2F2 (70% water requirement+10 ton ha-1 biochar+ with chemical fertilizer) and I2B3F2 (70% water requirement+20 t.ha-1 biochar+ with chemical fertilizer) treatments. Biochar significantly increased water use efficiency which shows that under water deficiency, biochar can increase the uptake of water and nutrients. As a result, plants tolerance against water deficiency increase and more yields will be produced for a specific value of water. This means the water use efficiency can increase and the use of water will decrease.  
    Conclusions
    This study confirmed that biochar application can help in increasing of black seed production through the improving some physical and chemical properties of the soil such as soil pH, soil nutrient availability, soil nutrient holding capacity, and soil microorganism conditions. Although the application of 20 ton ha-1 biochar improved soil properties compared with 10 ton ha-1, the difference was not significant.  Application of biochar with chemical fertilizers had better effects on seed and straw yield, compared with solely application of biochar and chemical fertilizers.  It may belong to the biochar ability to decrease nitrate and other elements leaching due to its high porosity and high water retention capacity which increased water use efficiency in the plant. This is important in particular, in arid and semi-arid areas, where reduces the amount of water consumed and increases water yields for plants that are under water stress. The seed production of black seed was not affected by reducing water requirements up to 70 % of its total water requirements when biochar was applied. This means that, by using the biochar in soil, only 70% water irrigation required. These results may use for water saving in agriculture in arid and semi-arid conditions.
    Keywords: Chemical fertilizer, Seed yield, Soil microbial biomass carbon, Soil organic matter
  • A Foroughi, A Biabani, A Rahemi Karizaki, Gh. A Rassam Pages 53-73
    Introduction
    Canola (Brassica napus L.) is one of the most important oil crops in the world. It has placed in third rank after soybean and palm and has the fastest of growth rate among oil seed in recent decades too. Canola yield was 1592 and 1567 kg.ha-1 in Iran and the world in 2003, respectively, however it has increased to 2125 and 2043 kg.ha-1 in Iran and the world in 2014, respectively. Crop physiologist should investigate the important physiological parameters which in the past have increased yield and can help to increase the quality and quantity of crop yield in the future. Therefore, the current study was carried out to evaluate the physiological traits associated with canola (Brassica napus L.) genotypes yield improvement.
    Materials and Methods
    Experiment was conducted as randomized complete block design with four replications at Higher Education Complex of Shirvan during growing seasons 2014-2015 and 2015-2016. Treatments were included 20 cultivars and lines of rapeseed. The record of phonological stages was done based on Sylvester-Bradley (1984)’s method. Before the plants showed elongation. Aboveground biomass and leaf area index (LAI) were measured from destructive sampling and it has been continuing at intervals of 6 to 10 d until physiological maturity. The ratio intercepted photosynthetic active radiation (PAR) was obtained by measuring of radiation at the top and bottom of the canopy with a Ceptometer (ACCUPAR model LP-80). Light was measured just before each destructive sampling between the hours of 12 to 14 on clear days. To calculate the daily cumulative solar active radiation we used RLY- calc program (Soltani, 2011). In order to investigation of growth indices, we have divided the varieties to three group based on cluster analysis and is select a variety as group representative. The groups are included high yield (Bilbao), medium yield (Karaje 3) and low yield (Sarigol).
    Results and Discussion
    Results indicated that there were significant differences among studied varieties in terms of phenological traits. So that Sarigol, Talayee, Shirali, Zafar and Zarfam were achieved earlier than others to physiological maturity. Positive and significant correlation of flowering duration with yield and the number of pod plant-1 has showed its importance in determination of yield. Positive and significant correlation among flowering duration with yield (r=0.66**) and the number of pod per plant (r=0.88**) showed its importance in determination of yield. Also, the most important of stage at making yield was affected by environmental conditions such as temperature, radiation and rainfall. LAI for Bilbao was higher than Sarigol and Karaje 3. Also, Sarigol was achieved maximum LAI earlier than two other varieties. There was strong correlation between yield and maximum dry matter accumulation (r=0.81**). The synchronization of maximum LAI with more solar radiation was much more important to achieve maximum yield. In the first year of experiment, crop growth rate (CGR) and relative growth rate (RGR) were higher than second. There was more solar radiation in first year that it was increased growth indices. The average extinction coefficient of light (KPAR) is estimated 0.70 and 0.72 in the first and second year of experiment respectively. In the first year of experiment, KPAR was varied between 0.65 (Shirali) to 0.76 (Modena and GKH-2005). In the second year, the highest and lowest extinction coefficient was belonged to the varieties Zafar (0.80) and Karaje 3 (0.63) respectively. The average of radiation use efficiency (RUE) is estimated between 3.8 and 3.6g MJ .m-2 in the first and second year respectively. Reducing light use efficiency in the second year can be probably because of obvious difference of weather between two years especially decreased of radiation. In other words, more scattered radiation in the second year than first year can be a major reason for this difference. In general, grain yield in the first was more than the second year of the experiment. The average yield of cultivars in the first and second year was 453.8 g.m-2 and 401.8 g.m-2 respectively. The highest yield in the first year belonged for Bilbao, Kodiak, SW102, GKH-305 and Traviata with the mean 495.5 g.m-2 and the lowest yield related to Zarfam, Sarigol, Talaei, Shiraly and Modena with the average amount of 370.5 g.m-2. The highest yield in the second year belonged to Bilbao, GKH-305, Slm046, L72, SW102, Kodiak and Traviata with the average amount of 450.3 g.m-2 and the lowest yield belonged to cultivars Talayeh, Opera, Karaj 3, Okapi, Modena, GKH-2005 and Karaj 1 with an average yield of 349.7 g.m-2. In general, cultivars with a higher LAI, as well as whose their maximum LAI coincided with higher radiation input had higher yield.
    Conclusions
    It can be concluded the importance of the synchronization maximum leaf area index with more solar radiation. For canola if the maximum LAI is less than four can say that growth and yield will be limited due to lack of leaf area because LAI about four is sufficient to obtain about 90 % of solar radiation. Therefore in spite of second year, in the first year LAI was not limiting factor to achieve maximum biomass. Since maximum LAI of canola occurs in flowering stage, so higher leaf area index at this time was caused the cultivars use more solar radiation. In addition to maximum LAI, the coincidence maximum LAI with higher radiation input was important factor to achieve a higher yield as a result more dry matter accumulation.
    Keywords: Extinction coefficient, Leaf area index, Phonological characteristics, Radiation use efficiency
  • D Sadeghzadeh, Ahari Pages 75-82
    Introduction
    Chickpea is the most important field crop among food legumes in Iran. According to the published statistic by agricultural ministry of Iran, cultivation area of chickpea varies between 550– 900 thousand hectares that more than of 90% them cultivated under dryland condition. More than 63% of country has cold and higher cold climates and more than 60% of drylands in Iran located in cold and highlands where temperature declines to -25°C in some years, with continues cold duration (more than 100 days per year). Reports show that the yield of chickpea is low in cold areas (about 500 kg.ha-1) because of the spring planting and lack cold tolerant cultivars suitable for autumn planting. In cold regions that absolute minimum temperature in winter reaches under -6°C till -12°C, studies showed that it may be complete damage occurrence if chickpea planted in autumn. Studies showed that planting of cold tolerance varieties increased the yield of chickpea almost twice. Hence, screening chickpea germplasms for cold tolerance will help to release new cold tolerant cultivars. The literature review suggests that most studies related to the evaluation and screening of chickpea cold tolerance were done under natural conditions (field), but the spatial and temporal variation in the weather under such circumstances may lead to different results. Researchers reported that using from controlled condition for screening cold tolerance genotypes in chickpea germplasm would prevent seasonal restrictions, saving time and increasing the accuracy of studies while eliminating unwanted factors.
    Materials and Methods
    In order to study on cold tolerance of 33 Kabuli chickpea genotypes along with three controls (Saral, ILC 533 and Jam), this study carried out in square lattice design (6×6) with two replications under controlled condition (cold room) at Maragheh Dryland Agricultural Research Station, during growing season 2014-2015 . Ten seeds of each genotype after surface sterilized with fungicide (Benomile with 0.015%) planted in five cm depth in planting boxes (100×80×25 cm) at early autumn (29 September). In order to simulation of natural growth condition in autumn and acclimation of seedlings, planted boxes incubated outside of green house. Number of germinated seeds was recorded and seedling of genotypes at six-week stage, incubated in cold room. The temperature of cold room decreased two degrees in each hour up to minus 15°C and seedlings remained for one hour at this temperature. A thin layer of ice nucleation active bacteria sprayed on the surface of seedlings at -2°C in order to establish ice nucleation and prevent ultra-freezing of seedlings. Then temperature increased up to 4°C for three days and boxes transferred to green house for two weeks under 20±3°C. Frost resistance ratios (FRR) of genotypes calculated and analyzed. According to other studies and reports the genotypes with 0.91-1 and 0.81-0.90 FRR classified in highly resistance and resistance groups, respectively.
    Results and Discussion
    Results showed that there was significant (p ≤ 0.01) differences in frost resistance ratio (FRR) among the investigated genotypes. Lines 14 (Flip98-138C* SEL99TER85074)*Sel.99th.15039, 28 (FLIP 00-84 C) and Saral cultivar had the highest FRR (100, 98 and 89 survived percentage, respectively) among the genotypes. Also Kaka cultivar and line 12 (Flip 98-28C*Flip 98-22C)* ICCV2 had the lowest frost tolerance among the studied genotypes. About 30% of genotypes could tolerate the frost damage, for example, genotypes 14 and 28 had between 0.9-1.0 ratio, whereas, the FRR of susceptible check (ILC533) was 0.13. 
    Conclusions
    The existence of wide range of diversity for frost resistance among the studied germplasm would be useful to introduce new tolerant chickpea cultivars with autumn-sown potential. Moreover, the tolerance of Saral cultivar to frost stress, its cultivation under cold dryland regions could be recommended as the first frost tolerant variety in the country.
    Keywords: Dryland, Frost resistance ratio, Line, Saral cultivar, Seedling
  • R Naseri, M Barary, M. J Zarea, K Khavazi, Z Tahmasebi Pages 83-98
    Introduction
    Current estimates indicate that 25% of the world agricultural lands are affected by water stress. Iran, with an annual 228 mm of rainfall, is classified as a dry region in the word. Wheat is one of the main cereal crops, cultivated for human feeding. In order to increase crop yield per unit area, largely chemical fertilizers are used. The result of these activities in recent years has been the crisis of environmental pollution, especially water and soil pollution that threatens human society. Phosphorus is one of the limiting elements for crop production. It is essential for energy transfer, photosynthesis and other biochemical and genetic activities of plant. Biofertilizers have been used as source to improve plant nutrients in sustainable agriculture. Phosphorus Solubilizing Bacteria (PSB) plays an important role in phosphorus nutrition by enhancing its availability to plants through release from inorganic and organic soils phosphorus pools by solubilizing and mineralization. Mycorrhizal crops often have greater tolerance to drought than nonmycorrhizal crops. The use of arbuscular mycorrhizal fungi capable of forming symbiotic associations with most agricultural crops and has potential under such systems due to its higher binding capabilities and mineral nutrition. Therefore, the main of this study was to study the effect of phosphate solubilizing bacteria and mycorrhizal fungi on root characteristics and grain yield in dryland wheat cultivars.
    Materials and Methods
    This experiment was carried out as factorial arrangement based on a randomized complete block design with three replications at the Agricultural Research Station of Ilam University (46*28' N, 33*37 E; elevation 1174 m) and Sarableh Agricultural Research, Recources Center (34*46 N, 33*45 E; elevation 975 m) during growing season 2013-2014. Experiment factors consisted of two dry land cultivars (Keras Sablan and Saji) and fertilizer sources including of 1: without application of phosphorious chemical fertilizer, 2: 50 kg.ha-1 phosphorous chemical fertilizer, 3: pseudomonas putida (PSB), 4: Glomus mosseae (GM), 5: PSB+GM, 6:PSB+GM+25 kg.ha-1phosphorous chemical fertilizer, 7: PSB+ 25 kg.ha-1 phosphorous chemical fertilizer and 8: GM+25 kg.ha-1phosphorous chemical fertilizer. At flowering stage root traits such as root volume, root area, root diameter, root length density and root surface area density were studied and measured. At full maturity, agronomic traits such as spikes.m-2, grains.spike-1, 1000-grain weight, grain yield and biomass yield were recorded using a sample of ten random guarded plants from the middle ridges of each plot. The data were analyzed statistically by SAS program and the data means were compared by Duncan's multiple range test (DMRT).
    Results and Discussion
    Results indicated that interaction effect between cultivar× fertilizer sources had significant effect on root length total, root volume, root area, root diameter, root length density, root surface area density, spike.m-2, grains.spike-1, 1000-grain weight, grain yield and biomass yield. Using fertilizer sources had  positive and significant effect on root traits and grain yield in two dryland wheat under dry land condition, so that Saji cultivar ×GM+25 kg.ha-1 had the highest root volume (4.6 cm3), root area (70.9 cm-2), root length density (0.158 cm root length.cm-3 soil), root surface area density (84.3 cm2.cm-3), spike.m-2 (257.5 spikes), grains.spike-1 (42.7 grains), 1000-grain weight (39.7 g), grain yield (3571.6 kg.ha-1) and biomass yield (7840.6 kg.ha-1) and the lowest root traits and grain yield belonged to Keras Sabalan×check treatment. There was significant different between cultivars to response of Using of phosphate solubilizing bacteria and mycorrhizal fungi, so that Saji cultivars had the best response to mycorrhizal fungi. Therefore with regard to cultivation of wheat is facing to drought and heat stress indicated that Saji cultivar and using of mycorrhizal fungi can be the best result under dry land conditions.
    Conclusions
    The results indicated phosphate solubilizing bacteria (PSB) and mycorrhizal fungi (GM) had positive effect on root system and grain yield, so that root traits and grain yield had the better status in presence of inoculation with GM. In fact PSB and GM could alleviate the partial of grain yield in presence of dry land farming. Recent studies indicated that symbiosis bio-fertilizers also improved soil physical and chemical traits and increaced organic matters content, root system and P available to coexistent plant.
    Keywords: Fertilizer sources, Grain yield, Root area, Root volume, Root system
  • B Masoudi Pages 99-110
    Introduction
    Sesame (Sesamum indicum L.) is considered as the queen of oilseeds for its high oil quality. Sesame oil is rich in micronutrients, antioxidants and essential amino acids as well as polyunsaturated fatty acids. Proper understanding of the relationship between grain yield and its components can significantly improve the performance of the breeding program through the proper use of selection indicators.
    Materials and Methods
    In order to determine the relationship between the seed yield and oil percentage with some important agronomic traits, and to find the direct and indirect effects of important agronomic traits on both seed yield and oil percentage and also select best genotypes in terms of different traits, 91 sesame genotypes (received from botanical gene banks of Germany, Canada and Australia) were studied based on an augmented design with 3 checks (Oltan, Yellow white, Naz tak shakheh) at seed and plant improvement institute, Karaj, Iran in 2016. 17 agronomic traits including flowering date, maturity date, first capsule height from surface of earth, height of plant, number of branches, number of capsule per branches, number of capsule per main stem, number of total capsule per plant, seed number per capsule, seed weight per capsule, 100-seed weight, capsule weight, capsule diameter, capsule length, oil percentage, biological yield and seed yield were studied.
    Results and Discussion
    The results of simple correlation indicated that seed yield per plant had a high correlation with total number of capsules per plant, number of capsules in branches, biological yield, number of capsules per main stem and plant height. Also 100 seed weight, seed yield per plant, number of capsules per main stem, number of capsules per plant and seeds weight per capsules were in a high correlation with oil percentage. The result of path analysis showed that the number of capsules per plant, number of capsules per branch, biological yield and capsule length exerted the greatest positive effects on seed yield and therefore suggest that they can used as selection criteria in seed yield improvement. Also seeds weight per capsule, capsule length, seed yield and number of capsules per main stem exerted the greatest positive effects on oil percentage. The results of principal component analysis showed that 6 components comprised 82.77 % of the total variations in genotypes. In the first components of this study biological yield, seed yield, capsule weight, number of capsules in the branches and number of capsules per plant had high positive coefficients. The number of seeds per capsule, the seed weight of a capsule and the weight of a capsule had the highest coefficients in the second component. In the third component, the traits of the day to the beginning of flowering and the day to the beginning of the maturity had the highest positive coefficients and the height of the plant had a high negative coefficient. In the fourth component, the weight of 100 seeds, oil percent and seed weight per capsule had the highest positive coefficients and the height of the first capsule from the ground surface had the highest negative coefficient. The fifth component, including oil percent, capsule length and height of the first capsule from the ground had positive coefficients and the numbers of capsules in the main branch were negative. Finally, the sixth component included the number of seeds per capsule and the number of capsules in the main branch with positive and 100-seed weight and the height of the first capsule from the surface with negative coefficients. Lao hong zhi ma and Black c-2-c, Dulce 101/87 and Bukbak had the highest yield in component 1 and 2 biplot. The genotype number 79, with the name of White c323-2, had a good relative yield and also a good relative seed oil content. In addition, genotypes number 79 and 51, with the names of White c323-2 and Local 123, have a good relative yield and also relatively early. Finally, genotype number 49, with the name of Lao hong zhi ma, had the highest relative yield and seed number per capsule.
    Conclusions
    For improvement of each component, we must pay attention to the related traits because gene or genes which control number of capsules per plant, probability control biological yield, capsule weight and other significant traits in this component too, and the component or gene which control this traits is similar gene or factor. By identifying these phenological and morphological patterns that effective in the structure of sesame and determining the relationships between them, breeders can use them in future programs.
    Keywords: Oil percentage, Path analysis, Principal component analysis, Seed yield
  • V Bahraini Vijuyeh, M. R Dadashi, S. M Nazeri Pages 111-121
    Introduction
    Wheat is important plant in the economy of the world. Between wheat cultivars, bread wheat (Triticum aestivum L.) is the best cultivar for nutrition. Drought stress led to decrease production, therefore, it causes problems for nutrition and agriculture. Iran is located in dry belt of the earth and its annual rain average is 250 mm. In dry land, grain filling phase is faced with a warm season when the air temperature is high and soil water storage is reduced. For screen best drought tolerant genotypes must use from drought tolerance and susceptibility indices. The purpose of this research was to identify and determine drought tolerant and high yield lines for introduction in drought stress conditions during reproductive phase and to determine the indices with a desirable efficiency for evaluating reaction of genotypes to stress conditions.
    Materials and Methods: An experiment based on randomized complete bock design with three replications was conducted Torogh Mashhad Agricultural Research Stations, Iran, during 2014-2016 growing seasons. In this research eight genotypes of winter wheat with three control cultivars of Mihan, Orum, zare were compared under two conditions of full irrigation and water stress during reproductive phase. Statistical analysis was performed by using SAS and SPSS software. After harvesting, yield and indices drought tolerance indices including SSI (Stress Susceptibility Index), STI (Stress Tolerance Index), GMP (Geometric Mean Productivity), HARM (Harmonic Index), MP (Mean Productivity), YSI (Yield Stability Index), YI (Yield Index), DI (Drought Index), MSTI (Modified Stress Tolerance Index), ATI (Abiotic Tolerance Index), SSPI (Stress Susceptibility Percentage Index), RE% (Reduction Percentage), SNPI (Stress non-Stress Production Index), TOL (Tolerance).
    Results and Discussion
     Results showed that the effect of year, genotype and irrigation and interaction effect between year and genotype were significant on all of studied traits. Drought stress decreased yield of genotypes about 32% and 30% in the first and second year, respectively. Other investigation showed that drought stress at the reproductive phase led to reduce current photosynthesis and high respiration. According to Fernandez, indices that have a significant correlation with grain yield in both stress and non-stress conditions are superior indices because they are able to distinguish high-yield genotypes in both conditions. In our research there was a significant and positive correlation between GMP, MSTI, HM, STI, MP with grain yield in both non-stress and stress conditions. In drought stress conditions genotype 8 and 9 ranked had the highest yield (5176 and 5079 kg ha-1), and were selected as the most tolerant genotype.
    Conclusions
    This research showed that drought stress at the reproductive phase reduced grain yield. GMP, MSTI, HM, STI and MP showed significant and positive correlation with grain yield in both non-stress and stress conditions. Genotype 8 had the highest rank in all of the mentioned indices, it could be considered as tolerant genotype to the drought stress at the reproductive phase due to the proper grain yield in both stress and non-stress conditions. 
    Keywords: Lake moisture, Productivity, Sustainability, Yield index
  • Kh Alizadeh, E Rezaei, Chiyaneh, R Amirnia, M Barin Pages 123-140
    Introduction
    Intercropping is defined as the growing of two or more crops at the same time in the same piece of land. Intercropping of legume with non-legume compared with monoculture has many advantages such as reducing the risk of crop failure, making efficient use of available land, improving productivity and income, more efficient use of resources (water, nitrogen, and radiation) and increasing food security in vulnerable production systems. Biofertilizers are important not only for the reduction of quality of chemical fertilizers but also for getting better yield in sustainable agriculture. Application of biofertilizers and no use of chemical fertilizers are rapidly gaining favor. Arbuscular mycorrhizal fungi (AMF) has been well documented to be a bio-fertilizers that have a symbiotic relationship with many crops and by increasing the uptake of nutrients mainly phosphorus, and enhancing the water absorption and resistance to pathogens, improves growth and yield of host plants in sustainable agricultural systems. The main objective of the present study was to determine the effect of biofertilizers (nitrogen, phosphorus, potassium and sulfur solubilizing bacteria+ Arbuscular mycorrhizal fungi) and intercropping on seed yield and yield components of linseed and faba bean.
    Materials and Methods
    This experiment was conducted as factorial layout based on randomized complete block design with three replications at the Research Farm of the Faculty of Agriculture, Urmia University, Iran, during growing season of 2017. The first factor was five intercropping patterns including 1 row linseed + 1 row faba bean, 2 row linseed + 2 row faba bean, 3 row linseed + 3 row faba bean, and monocropping of each crop and the second factor was included control (no fertilizer), and biofertilizers (nitrogen, phosphorus, potassium and sulfur supplier bacteria+ arbuscular mycorrhiza fungi). Before the sowing, the related biofertilizers were shaked completely to cover the whole seeds surface after which the seeds were shadow-dried and planted, irrigation was done immediately after seed sowing. No fertilizer was used during the growing season. In addition, the land equivalent ratio (LER) was calculated to determine the advantages of intercropping. The Analysis of variance was performed using SAS 9.4 software; means were compared by using Duncan's multiple test at 0.05 probability level.
    Results and Discussion
    The results showed that the effect of cropping pattern on all measured traits was significant on height, number of lateral branch, number of capsule per plant, number of seed per capsule, 1000-seed weight, biological yield, seed yield, oil percentage of linseed and on height, number of lateral branch, number of pod per plant, number of seed per pod, 1000-seed weight, biological yield, seed yield of faba bean. The highest seed yield of faba bean (4.280 t ha-1) and linseed (2.230 t ha-1) were obtained in monocropping treatments, respectively. The higher production in linseed and faba bean monocropping may be due to the less disturbance in the habitat in homogeneous environment under monocropping systems. The results showed that biofertilizer had a significant effect on all traits, in linseed and faba bean. The highest yield and yield componenet of both plants were achieved in use of biofertilizers. In linseed, the highest oil percentage of all treatments was higher than solecropping. Also, total LER was more than 1 and the highest values were observed in all treatments. The maximum LER values (1.50) were obtained for intercropping 2 row of linseed + 2 row of fababean with using biofertilizers. It seems that better utilize of the growth resource in the intercropping led to reach this result.
    Conclusions
    In general, the results of this experiment showed that the faba bean and linseed yield were influenced by different intercropping patterns and biofertilizer. The highest seed yield for both plants (faba bean and linseed) were achieved in monocropping. In the present study, application of biofertilizers could improve the yield and some characteristics of faba bean and linseed. In addition, with application of biofertilizer the seed yield of linseed and faba bean about 38% and 31% compared with control (non-consumption), respectively. It seems that the use of biofertilizers in intercropping is one of the suitable strategies for achieving optimal yields with minimum inputs, which in the long run can reduce the need of crop systems to chemical inputs.
    Keywords: Azotobacter, Land equivalent ratio, Oil, Planting pattern, Pseudomonas
  • A. A Rostami Ajirloo, M. R Asgharipour, A Ganbari, M Joudi, M Khoramivafa Pages 141-155
    Introduction
    According to the present state of climate science, the increase in greenhouse gas concentrations will result in changes of the climate parameters; particularly, an increase of the global temperature and changes in precipitation are expected. These changes in climate, which are likely to occur during future decades, may have significant consequences (positive or negative) on the development, growth, and crops yield. Climate change and its impacts on water recourses is known as one of the most important challenges which human would be faced with it in future century. Future climate change in each region can be predicted through the models of the Globa Circulation Model (GCM). It is also possible to investigate the effect of climate change on the yield and the water requirement of plants using performance predictive models as Aquacrop model. The main objective of this study is to assess the effect of climate change on the future climate of Moghan plain and also, simulation three corn hybrids parameters such as grain yield, biomass yield and growth period of corn, under different irrigation treatments.
    Materials and Methods
    In this study, AquaCrop model was used to simulate grain yield and biomass of different maize hybrids under the future climate in different irrigation treatments. For this purpose, rainfall data, minimum temperature, maximum temperature and sunshine model of the LARS-WG fine-scale model with using six general circulation models (ADCM3, HadCM3, IPCM4, GFCM2, NCCCSM INCM3), for which three scenarios the fourth report of the Climate Change Board (A1B, A2, and B1) was predicted and reviewed for the Moghan region during 1970-2010, 2011-2030 and 2046-2065. AquaCrop model was calibrated and validated by field data (2015 and 2016 year), corn plants collected in the area. Then, the grain and biomass yield values in the upcoming periods for different irrigation treatments (I1 = normal irrigation, I2 = irrigation cut off at vegetative growth stage, I3 = irrigation cut during flowering stage and I4 = irrigation cut off at the seed filling stage) different maize hybrids (C1 = SC704, C2 = SC703 and C3 = SC705).
    Results and Discussion
    According to the results, in the statistical period of 2011-2030 compared base periods (1970-1999), the average monthly temperature was 1.41, 1.35, and 1.66 ° C, respectively for scenarios A1B, A2, and B1. Also, the average monthly rainfall will be reduced to of 6, 11 and 15 mm, respectively, for scenarios A1B, A2 and B1, and during 2046-2065 periods, compared to period of 1979-2010. Furthermore, the monthly average of the temperature will be increased to 2.9, 2.69 and 2.32 ° C respectively, for scenarios A1B, A2 and B1. During this period, the amount of rain reduction was estimated at 18, 15 and 14 millimeters, respectively, in scenarios A1B, A2, and B1. The results of simulation of grain yield and total biomass of maize cultivars under the influence of irrigation administrations using AquaCrop model showed that the root mean square variables of seed and dry matter yield errors in years 2015 and 2016 were 413 and 891 kg.ha-1. The root mean square mean of normalized error of seed and dry matter yield was 11 and 10%, respectively. Also, with using future meteorological data under different scenarios was observed that growth period, grain yield and biomass yield during 2011-2030 and 2046-2065 periods for three scenarios A2, B1 A1B were decreased. Among the cultivars studied, Hybrid SC704 corn had more growth and yield than other corn hybrids, and this figure could be recommended for future climate change for Moghan area.
    Conclusions
    Future meteorological data under different scenarios of climate change will decrease growth period, grain yield and biomass yield during 2011-2030 for scenarios A1B, A2 and B1, respectively, 7 %, 16 % and 9%, and during period 2045-2065 for scenarios A1B, A2 and B1, respectively, 13 %, 14 % and 12 percent. Among the cultivars studied, the growth period of SC 704 hybrid was higher for all three scenarios than other hybrids and it has more growth and yield, therefore can recommended to change future climate for Moghan region.
    Keywords: AquaCrop model, Climate, Drought stress, Water crisis
  • A Abhari, E Gholinezhad Pages 157-167
    Introduction
    Drought stress has osmotic and physiological effects on plants, resulting in reduced growth, metabolic disorders and oxidative stress in plants. Different plants use several strategies to cope with drought stress. External application of different compounds such as organic solvents and minerals is a solution to increase drought tolerance in plants. Salicylic acid is recognized as a plant hormone and its role in defense mechanisms against biological and non-biological stressors is well defined. The purpose of this experiment was to evaluate the effect of salicylic acid on reducing the effects of drought stress on yield, water use efficiency and some physiological characteristics of the barely.
    Materials and Methods
    This experiment was carried out as factorial experiment based on randomized complete block design with three replications in the Kizor fields located in the city of Sabzevar in 2017. The altitude of this area is 1195 m above sea level and is 36° 5 N latitude and 44° 3' E longitude. The treatments included irrigation at two levels of cut-off irrigation (irrigation cut from booting to harvesting stage) (Z39) and non-cut-off irrigation and salicylic acid spraying treatment at four levels of zero (control), two, four and six mM at stage of shoots on barley. Data were analyzed with the SAS software ver 9.1 and the means were compared with LSD test.
    Results and Discussion
    The results showed that in both conditions of non-cut-off irrigation and cut-off irrigation, the highest number of spikes, number of seeds, seed yield and biological yield per m2 were obtained in two to six mM of salicylic acid, respectively, and the lowest was related to control treatment. The lowest water use efficiency (0.38) was obtained under non-cut-off irrigation conditions without salicylic acid and with the consumption of salicylic acid up to six mM, water use efficiency increased. Also, salicylic acid spraying in cut-off irrigation conditions compared to non-cut-off irrigation led to increase water use efficiency. In both conditions, non-cut-off irrigation and cut-off irrigation, the highest and lowest grain yields were obtained from 6 mM salicylic acid and control treatments (without salicylic acid spraying), respectively. Under non-cut-off irrigation and cut-off irrigation, spraying with 6 mM of salicylic acid increased the grain yield by 44% and 48% compared to control (without salicylic acid spraying). It seems that the effect of salicylic acid spraying in cut-off irrigation conditions was more effective than non-cut-off irrigation conditions. The cause of higher water use efficiency in cut-off irrigation conditions in comparison with non-cut-off irrigation was high waste of water due to evapotranspiration and deep penetration in non-cut-off irrigation treatments. Spraying with salicylic acid by stimulating the growth of hair and sub-roots plays an effective role in increasing water use efficiency. In cut-off irrigation conditions, salicylic acid consumption has reduced the amount of electrolyte leakage so that the spray at a concentration of 6 mM of salicylic acid compared to the control (without salicylic acid spraying) decreased electrolyte leakage about 38 %. The reduction of membrane damage due to the use of salicylic acid is related to the production of antioxidants. Spraying with salicylic acid increases the stability of the membrane against oxidative stresses.
    Conclusions
    Water deficit at first affecting the structure of the cell membrane, increased the permeability of the membrane relative to the ions and macromolecules and at second stage decreased the photosynthesis by decreasing the chlorophyll index, which finally reduced the yield and its components. Also, salicylic acid alleviate drought stress by reducing ion leakage, increasing proline concentration and chlorophyll index resulting to improved wheat grain yield under cut-off irrigation conditions compared to non-cut-off irrigation.
    Keywords: Chlorophyll index, Cut-off irrigation, Grain Yield, Ion leakage, Porolin
  • S. F Saberali, H Nastari, Nasrabadi, M Dostkhah, Ahmadi Pages 169-186
    Introduction
    Wheat production is an important component for national food security. Studying the impact of future climate change on crop production is crucial to manage crop productivity. Improving our understanding of potential responses of the wheat plant to these changes while taking into consideration agricultural management is required for identifying best adaptation strategies. In Khorasan Razavi province, over 12% of the total cultivated wheat area is belong to Torbat-e Jam region. The current study aimed to quantify the potential impacts of climate change on irrigated wheat yield in the next 30 years for this region.
    Materials and Methods
    In this study, information on regional cropping systems and meteorological data to study the effects of climate change were collected and finally, the impact of climate change on irrigated wheat yield was studied using simulation approaches under different climatic scenarios. Long-term daily weather data for future was generated using MarkSim weather generator software and the past meteorological data was gathered from regional weather station. Daily weather data generated by four scenarios RCP2.6, RCP4.5, RCP6, and RCP8.5 for a 30-year period. The generated and measured daily weather data was used for running CERES-Wheat model. Finally, crop model outputs were used to interpret climate change impacts on wheat growth and production.
    Results and Discussion
    The average air temperature during the wheat growth period showed that temperature increased about 1.6% in the last five years compared to the first five years of the baseline 30-years period. Furthermore, the average annual precipitation for the last 5 years was 51 mm less than the first 5 years of the baseline period. The air temperature will increase about 1.1, 1.6, 1.2 and 1.8 °C during the wheat growth period for the near future (30 years) under the RCP2.6, RCP4.5, RCP6, and RCP8.5 scenarios, respectively. The precipitation over the wheat growth period will reduce by 9 and 8% under RCP4.5 and RCP8.5 scenarios, respectively. Furthermore, the precipitation over the growth period would increase by 11 and 17% under RCP2.6 and RCP6 scenarios, respectively. The simulated wheat yield by the CEREC-Wheat model showed that the grain yield increased by 5% in the first 5 years compared to the last 5 years of the baseline period (1998-2017). The biomass production and harvest index (HI) also increased by 2.3 and 1%, respectively. The increased dry matter production and HI can be due to temperature increase during the cold seasons, and more amount of precipitation during the reproductive growth. The simulated wheat growth during the near future period (2018-2047) showed that wheat growth cycle will reduce from 5 to 7 days under different emission scenarios. In the different soil textures, wheat yield under RCP2.6, RCP4.5, RCP6, and RCP8.5 scenarios will increase by 24.4, 19.9, 24.9 and 25.2%, respectively. Furthermore, the highest and the lowest yield were obtained from clay and sandy clay loam soils, respectively. Under the different emission scenarios, the mean incident light and light use efficiency during the growth period would be increased by 20.8-24.6% and 5.5-8.3%, respectively, in projected climate change as compare to baseline period. Reducing irrigation water as amount of 300 m3 ha-1 and simultaneous increase in irrigation water use efficiency are possible incident scenarios for the near future. Based on these scenarios, simulations showed that grain yield increased 26.3, 19.6, 27.2 and 25.6 % under RCP2.6, RCP4.5, RCP6, and RCP8.5 emission scenarios, respectively. 
    Conclusions
    The increased temperature and atmospheric CO2 concentration during the next 30 years will decrease wheat growth cycle, but increase the potential biomass and grain wheat yield under the different emission scenarios. The results showed that the increased yield production will occur under climate change conditions, even if the available irrigation water would decrease by 300 m3 ha-1.
    Keywords: Diffusion scenario, DSSAT, MarkSim, Simulation, Temperature rise