فهرست مطالب

  • سال هفدهم شماره 3 (1398)
  • تاریخ انتشار: 1398/06/10
  • تعداد عناوین: 12
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  • فاطمه قریشی، امیر لکزیان*، امیر فتوت، حمید ذبیحی صفحات 359-372
    روش های مدیریتی بقایای گیاهی با تاثیر بر ویژگی های خاک، می تواند نقش موثری در بهبود باروری و کیفیت خاک و همچنین افزایش عملکرد محصول داشته باشند. به منظور بررسی تاثیر مدیریت های مختلف بقایای گیاهی گندم و چغندرقند بر برخی ویژگی های شیمیایی و زیستی خاک، دو طرح آزمایشی مجزا در قالب طرح پایه کاملا تصادفی با سه تکرار به اجرا درآمد. نتایج نشان داد که مدیریت های مختلف بقایای گیاهی گندم و چغندرقند موجب تغییرات معنی داری بر ویژگی های شیمیایی (غیر از اسیدیته) و زیستی مورد مطالعه شدند. تمام روش های مدیریتی نظیر سوزاندن بقایا، مخلوط کردن بقایا، مخلوط کردن بقایا همراه با کود شیمیایی به جز رهاسازی بقایا در سطح خاک موجب افزایش مقدار کربن آلی، نیتروژن کل، فسفر قابل دسترس و پتاسیم قابل دسترس خاک نسبت به تیمار شاهد شدند. به طور کلی در هر دو بقایای گیاهی بیشترین مقدار کربن آلی، نیتروژن کل و پتاسیم قابل دسترس مربوط به تیمار بقایای گیاهی به همراه کود اوره و شخم بود. در مورد تنفس میکروبی پایه و کربن زیست توده میکروبی خاک موثرترین روش های مدیریتی تیمار بقایای گیاهی به همراه شخم بود. همچنین در این پژوهش اگرچه تیمارهای سوزاندن بقایای گیاهی موجب بهبود وضعیت عناصر غذایی، تنفس میکروبی پایه و کربن زیست توده میکروبی نسبت به تیمار شاهد شدند ولی کارایی کمتری نسبت به تیمارهای شخم و افزودن کود به بقایا داشتند. براساس نتایج می توان گفت مناسب ترین روش از نظر ارتقای شاخص های کیفی خاک در هر دو بقایای گندم و چغندرقند مخلوط کردن بقایا به وسیله شخم با خاک به همراه کود اوره و همچنین مخلوط کردن بقایا به وسیله شخم با خاک بوده است.
    کلیدواژگان: سوزاندن بقایا، شخم بقایا، عناصر غذایی
  • اشکان عسگری، علی رضا کوچکی، پرویز رضوانی * صفحات 373-387
    این مطالعه با هدف تعیین مناسب ترین سن نشاء و تراکم از نظر عملکرد و اجزای عملکرد عروسک پشت پرده در مزرعه تحقیقاتی دانشکده کشاورزی دانشگاه فردوسی مشهد در سال زراعی 95-1394 انجام شد. آزمایش به صورت فاکتوریل در قالب طرح بلوک های کامل تصادفی با سه تکرار بود. فاکتورهای آزمایش شامل سه سن نشاء (5، 8 و 11 هفته) و چهار تراکم بوته (5، 7/6، 10 و 20 بوته در متر مربع) بود. نتایج نشان داد بیشترین وزن میوه (92 گرم) در بوته مربوط به تیمار سن نشاء 11 هفته با تراکم 5 بوته بود. بیشترین عملکرد بیولوژیک در تیمارهای سن نشاء 11 و 8 هفته در تراکم 20 بوته به میزان 16 تن در هکتار به دست آمد. بیشترین عملکرد میوه (1/7 تن) در تیمار سن نشاء 11 هفته با تراکم 10 بوته در متر مربع بالاترین مقدار بود. همچنین بیشترین تعداد میوه با میانگین 109 عدد در سن نشاء 11 هفته با تراکم 5 بوته در متر مربع حاصل شد. ارتفاع بوته در تراکم 20 بوته (61 سانتی متر) بیشتر از تراکم های دیگر بود و همچنین ارتفاع در سن نشاء 11 و 8 هفته (به ترتیب 52 و 54 سانتی متر) بیشتر از سن 5 هفته بود. شاخص برداشت در تراکم های 5، 7/6 و 10 بوته در سن 11 و 8 هفته بیشترین و در تراکم 20 بوته کمترین مقدار را داشت. به طور کلی نشاهای با سن 5 هفته از نظر بیشتر صفات وضعیت مناسبی نداشتند و همچنین تراکم 20 بوته در متر مربع نیز در تمامی صفات به جز عملکرد بیولوژیک و ارتفاع بوته مناسب نبودند.
    کلیدواژگان: ارتفاع بوته، شاخص برداشت، عملکرد بیولوژیک، عملکرد میوه، وزن هزار دانه
  • هانیه همافر، محمود خرمی وفا*، فرزاد مندنی، حیدر ذوالنوریان صفحات 389-401
    اختلافات فیزیولوژیک و مورفولوژیک دو محصول اقتصادی و ارزشمند سیب زمینی و ذرت شیرین و همچنین عدم تداخل در برداشت، دلایل کافی و منطقی برای کشت مخلوط آن هاست. بااین حال، برای یافتن بهترین ترکیب مناسب کشت این دو گیاه، اطلاعاتی چون کارایی در مصرف منابع تولید اهمیت دارد. از این رو به منظوربررسی جذب و کارایی مصرف نور در کشت مخلوط ذرت شیرین و سیب زمینی، آزمایشی در قالب طرح بلوک های کامل تصادفی با 3 تکرار در مزرعه تحقیقاتی پردیس کشاورزی و منابع طبیعی دانشگاه رازی کرمانشاه در سال زراعی 1392 اجرا شد. تیمارهای آزمایشی در شش سطح، عبارت از الگوهای کشت مخلوط 1:1، 2:2، 2:1 و 1:2 (به ترتیب نشان دهنده ردیف های کاشت ذرت شیرین و سیب زمینی) به همراه کشت خالص آن ها بودند. نتایج نشان داد که شاخص سطح برگ و کارایی مصرف نور برای هر دو گیاه و در تمام الگوهای کشت مخلوط نسبت به تک کشتی بالاتر بود. در بین الگوهای مختلف کشت مخلوط، بیشترین کارایی مصرف نور برای هردو گیاه ذرت شیرین و سیب زمینی، به الگوی 1:2 به ترتیب معادل 2/18 و 1/86 گرم بر مگاژول، مربوط بود، درحالی که بیشترین عملکرد قابل کنسرو ذرت شیرین (3300 کیلوگرم در هکتار) و سیب زمینی (9460 کیلوگرم در هکتار) به ترتیب از الگوهای 2:1 و 2:2 به دست آمد. به طورکلی نتایج این بررسی نشان داد که کشت مخلوط ذرت شیرین و سیب زمینی جذب نور کارآمدتری نسبت به تک کشتی آن ها دارد، و از نظر اقتصادی، کشت دو ردیف سیب زمینی همراه با دو ردیف ذرت (LER=1/41) توصیه می شود.
    کلیدواژگان: بهره وری، کارایی مصرف منابع، الگوی کاشت
  • زین العابدین جویبان، محمد کافی*، احمد نظامی، سید غلام رضا موسوی صفحات 403-414
    استفاده بهینه از منابع آب موجود، به همراه بهبود کارایی عناصر غذایی در شرایط تنش خشکی، ضمن کمک به تحقق اهداف کشاورزی پایدار، سبب افزایش و یا ثبات عملکرد گیاهان زراعی نیز می شود. این مطالعه با هدف بررسی اثرات تنش خشکی و عناصر نیتروژن و پتاسیم بر عملکرد و برخی خصوصیات فیزیولوژیک گیاه ارزن پادزهری (Panicum antidotale Retz.) در شرایط آب و هوایی بیرجند در خراسان جنوبی انجام شد. آزمایش به صورت اسپلیت فاکتوریل در قالب طرح بلوک های کامل تصادفی در سه تکرار در مزرعه تحقیقاتی دانشگاه آزاد اسلامی بیرجند انجام شد. فاکتورهای آزمایش شامل آبیاری بر اساس تبخیر تجمعی از تشتک تبخیر در سه سطح (70، 140 و 210 میلی متر)، نیتروژن بر اساس آزمون خاک در سه سطح صفر، مصرف به میزان نصف مقدار قابل توصیه آزمون خاک (100 کیلوگرم در هکتار) و مصرف بر اساس مقدار قابل توصیه آزمون خاک (200 کیلوگرم در هکتار) و پتاسیم در دو سطح (صفر و 100 کیلوگرم در هکتار) بود. نتایج نشان داد که با افزایش تبخیر تجمعی رطوبت از تشتک تبخیر و یا کاهش آب مصرفی، کارایی مصرف تشعشع کاهش و کارایی مصرف آب افزایش یافت. همچنین با افزایش نیتروژن مصرفی، کارایی مصرف نیتروژن کاهش یافت. در صفت عملکرد ماده خشک در مجموع چین ها، اثر متقابل سه گانه رژیم آبیاری و کودهای نیتروژن و پتاسیم معنی دار بود و کاربرد این عناصر در زمان افزایش شدت تنش، صفت فوق را بهبود داد. در مجموع به نظر می رسد که کاربرد عناصر نیتروژن و پتاسیم در شرایط تنش خشکی، می تواند در کاهش اثرات مخرب تنش و افزایش تحمل ارزن پادزهری به خشکی موثر باشد.
    کلیدواژگان: تنش خشکی، کارایی مصرف آب، عناصر غذایی
  • زهرا تقی پور*، رسول اصغری صفحات 415-425
    به منظور مطالعه اثر تنش خشکی در شرایط آبیاری کامل و تنش رطوبتی انتهای فصل (قطع آبیاری در مرحله تورم غلاف برگ پرچم و قطع آبیاری در مرحله 50% ظهور سنبله) روی صفات مختلف هشت اکوتیپ triuncialis Aegilops و تعیین صفات موثر بر عملکرد دانه، آزمایشی به صورت فاکتوریل بر پایه طرح کاملا تصادفی با سه تکرار اجرا شد. تنش رطوبتی موجب کاهش مقادیر کلیه صفات مورد ارزیابی مخصوصا عملکرد دانه به میزان 89% نسبت به شاهد شد. شرایط تنش رطوبتی با آسیب بر دستگاه فتوسنتزی باعث کاهش کارآیی فتوشیمیایی فتوسیستم II و شاخص کلروفیل گردید. میزان هدایت روزنه ای در شرایط تنش در مرحله تورم سنبله 46 درصد و در مرحله 50 درصد ظهور سنبله 55 درصد کاهش یافته و همچنین موجب کاهش26 درصدی محتوی نسبی آب برگ نسبت به شرایط نرمال گردید. اگرچه اعمال تنش رطوبتی در این آزمایش باعث کاهش عملکرد دانه در اکوتیپ ها نسبت به شرایط بدون تنش شد ولی بعضی از اکوتیپ ها مانند هشترود، هوراند و ماکو شرایط تنش را تحمل نموده و کاهش عملکرد کمتری نسبت به سایرین نشان دادند. اکوتیپ های هشترود، مرند، هوراند، البرز و مشکین توانستند در زمان خشکی، با افزیش طول ریشه رطوبت مورد نیاز را از اعماق خاک فراهم کنند.
    کلیدواژگان: تنش رطوبتی، فلورسانس کلروفیل، عملکرد دانه، هدایت روزنه ای
  • هدا لطیفی، سرور خرم دل*، جواد وفابخش، عبداله ملافیلابی، مهدی نصیری صفحات 427-439
    بهینه سازی نیتروژن و تراکم یکی از راهکارهای مدیریتی برای حفاظت از منابع و کاهش آلودگی های زیست محیطی محسوب می شود. مدل سطح پاسخ (RSM) مجموعه ای از تکنیک های آماری مورد استفاده برای بهینه سازی نهاده های تولید به شمار می آید. در این مطالعه، اثر کود نیتروژن و تراکم بوته کنجد با استفاده از طرح مرکب مرکزی (CCD) برای مدل سطح پاسخ بررسی شد. این آزمایش با 13 تیمار و دو تکرار در مزرعه تحقیقاتی دانشکده کشاورزی دانشگاه فردوسی مشهد در سال زراعی 95-1394 انجام شد. تیمارها بر اساس سطح پایین و بالای تراکم بوته (به ترتیب با 10 و 40 بوته در متر مربع) و نیتروژن (به ترتیب با صفر و 100 کیلوگرم اوره در هکتار) تعیین شدند. ارتفاع بوته، اجزای عملکرد (شامل تعداد کپسول در بوته، تعداد دانه در کپسول و وزن هزار دانه)، عملکرد دانه، عملکرد بیولوژیک، شاخص برداشت، درصد روغن، عملکرد روغن، درصد پروتئین و عملکرد پروتئین به عنوان متغیر وابسته مورد اندازه گیری قرار گرفتند و تغییرات این متغیرها با استفاده از مدل رگرسیونی ارزیابی شد. به منظور ارزیابی کیفیت مدل برازش شده از آزمون عدم برازش استفاده شد. بسندگی مدل با استفاده از آنالیز واریانس مورد ارزیابی قرار گرفت. به طور کلی، معادله چند جمله ای درجه دوم کامل برای تعیین معنی داری مدل و اجزای مدل (خطی، درجه دو و اثر متقابل) مورد بررسی قرار گرفت.کیفیت مدل برازش شده با استفاده از ضریب تبیین (R2) ارزیابی شد. نتایج نشان داد که اثر جزء خطی بر تمام صفات مورد مطالعه معنی دار بود. اثر جزء درجه دو کامل تمام صفات به جز شاخص برداشت، تعداد دانه در کپسول و وزن هزار دانه را به طور معنی داری تحت تاثیر قرار داد. اثر متقابل دو عامل نیتروژن و تراکم بوته تنها بر کارایی مصرف نیتروژن، ارتفاع بوته و تعداد کپسول در بوته و درصد پروتئین معنی دار بود. آزمون عدم برازش در مورد هیچ کدام از صفات معنی دار نشدکه این امر نشان دهنده برازش مطلوب مدل رگرسیون درجه دوکامل بود. بیشترین عملکرد دانه مشاهده شده و برازش شده به ترتیب برای تراکم 25 بوته در متر مربع و 50 کیلوگرم کود اوره در هکتار و تراکم 25 بوته در متر مربع و 100 کیلوگرم کود اوره در هکتار با 1320/52و 1272/45کیلوگرم در هکتار به ترتیب به دست آمد. بیشترین درصد روغن و درصد پروتئین مشاهده شده به ترتیب از تراکم 10 بوته در متر مربع و عدم مصرف اوره (46/67درصد) و 40 بوته در متر مربع و 100 کیلوگرم اوره در هکتار (25/31درصد) حاصل شد و بالاترین مقادیر مشاهده شده این صفات به ترتیب مربوط به تراکم 10 بوته در متر مربع و عدم مصرف اوره (49/46 درصد) و 40 بوته در متر مربع و 100 کیلوگرم اوره در هکتار (25/01درصد) بود. به طور کلی، اثر تراکم بوته بر افزایش عملکرد در سطوح بالای کود نیتروژن افزایش یافت که به طور آشکار نشان ‎دهنده اهمیت نیتروژن در بهبود عملکرد دانه کنجد می باشد. بهینه سازی میزان مصرف منابع با استفاده از طرح مرکب مرکزی می تواند به عنوان راهکاری مطلوب در تولید پایدار کنجد مد نظر قرار گیرد.
    کلیدواژگان: آزمون عدم برازش، تولید پایدار، مدل سطح پاسخ
  • حسین کمائی، حمیدرضا عیسوند*، ماشاالله دانشور، فرهاد نظریان صفحات 441-455
    به‏ منظور بررسی اثر محلول ‏پاشی پتاسیم و روی بر شاخص ‏های فیزیولوژیک رشد، پارامترهای فلئورسانس کلروفیل و عملکرد دو رقم گندم نان تحت تاریخ کاشت تاخیری، آزمایشی به ‏صورت کرت‏ های دو بار خرد شده در قالب طرح پایه بلوک‏ های کامل تصادفی با سه تکرار در شهرستان رامهرمز اجرا گردید. عامل‏ های آزمایشی شامل تاریخ کاشت در دو سطح مناسب (30 آبان) و تاخیری (15 دی) به‏عنوان عامل اصلی، محلول ‏پاشی در چهار سطح با آب (شاهد)، پتاسیم، روی و پتاسیم + روی به‏ عنوان عامل فرعی و دو رقم گندم نان پیشتاز و چمران 2 به‏عنوان عامل فرعی فرعی بودند. نتایج نشان داد که تاریخ کاشت تاخیری به ‏دلیل تنش گرمای انتهایی شاخص سطح برگ (LAI) (25/95درصد)، دوام سطح برگ (LAD) (48/44درصد)، سرعت رشد محصول (CGR) (21/76درصد)، سرعت رشد نسبی (RGR) (13/72 درصد)، سرعت جذب خالص (NAR) (22/43درصد)، حداکثر عملکرد کوانتومی فتوسیستم II در شرایط سازگار شده با تاریکی (Fv/Fm) (3/25 درصد)، عملکرد کوانتومی موثر فتوسیستم  II(ΦPSII) (4/37 درصد)، حداکثر عملکرد کوانتومی فتوسیستم  IIدر شرایط سازگار شده با روشنایی (Fv'/Fm') (3/24 درصد) و عملکرد دانه (27/02درصد) ارقام گندم نان را به ‏طور معنی‏ داری کاهش داد، اما موجب افزایش معنی ‏دار خاموشی غیرفتوشیمیایی (NPQ) (22/73درصد) گردید. محلول‏ پاشی پتاسیم و روی غیر از NPQ صفات LAI (17/50درصد)، LAD (17/62درصد)، CGR (33/49درصد)، RGR (12/00درصد)، NAR (37/62درصد)، Fv/Fm (3/12درصد)، ΦPSII (7/37درصد)،Fv'/Fm' (6/65 درصد) و عملکرد دانه (17/30درصد) ارقام گندم نان را تحت تاریخ کاشت تاخیری به طور معنی‏ داری بهبود بخشید. به‏ طور کلی، استفاده از محلول‏پاشی روی و روی + پتاسیم در رقم چمران 2 به ‏عنوان بهترین ترکیبات تیماری در بهبود صفات فیزیولوژیک و عملکرد دانه در هر دو تاریخ کاشت مناسب و تاخیری توصیه می‏شود.
    کلیدواژگان: تنش گرمای انتهایی، عناصر غذایی، غلات
  • وحید محصلی*، فرزاد فربود صفحات 457-465
    کمبود آهن در گیاهان عمدتا در خاک های آهکی و قلیایی مشاهده می شود. با توجه به این که شرایط شیمیایی این خاک ها علت اصلی بروز کلروزآهن می باشد و از طرفی به دلیل گران بودن کودهای آلی حاوی آهن لذا استفاده از ترکیبات آلی طبیعی و غنی شده از آهن مانند پودر خون نیز می تواند در برطرف نمودن کلروز آهن موثر باشد. بنابراین هدف از پژوهش حاضر، بررسی توان پودر خون در تامین آهن مورد نیاز گیاه بادرنجبویه بود. آزمایش فوق با سه سطح آهن (صفر، 2/5 و 5 میلی گرم آهن در کیلوگرم خاک) از منبع سکسترین آهن و چهار سطح پودر خون (صفر، 0/75، 1/5 و 3 گرم پودر خون در کیلوگرم خاک) بر روی گیاه دارویی بادرنجبویه (Melissa Officinalis L.) اجرا گردید. پس از اتمام دوره رشد رویشی، وزن ماده خشک، غلظت آهن، کلروفیل a و b، کاروتنوئیدها و میزان اسانس گیاه اندازه گیری شد. نتایج نشان داد که کاربرد کود آهن و پودر خون سبب افزایش معنی داری در وزن خشک، غلظت آهن، کلروفیل، کاروتنوئیدها و عملکرد اسانس در گیاه بادرنجبویه گردید. حداکثر وزن خشک گیاه 141/4گرم در گلدان در شرایط مصرف کود آهن و پودر خون به ترتیب به میزان 2/5 میلی گرم و 1/5 گرم در کیلوگرم به دست آمد. مصرف پودر خون در سطوح اول، دوم و سوم آهن به ترتیب سبب 13/8، 6/8 و 11/7 درصد افزایش در غلظت آهن گیاه شد. کاربرد آهن و پودر خون به ترتیب به میزان 5 میلی گرم و 3 گرم در کیلوگرم سبب افزایشی معادل 241/7 درصد در میزان اسانس گیاه نسبت به شاهد گردید. همچنین مصرف همین میزان آهن و پودر خون باعث تولید حداکثری عملکرد اسانس (308/5درصد افزایش نسبت به شاهد) شد.
    کلیدواژگان: آهن، ترکیبات آلی، میزان و عملکرد اسانس، وزن خشک
  • نفیسه اسدی نسب، مجید نبی پور*، حبیب الله روشنفکر، افراسیاب راهنما صفحات 467-476
    این پژوهش به منظور مطالعه تاثیر محلول پاشی اسیدسالیسیلیک و اسیدآبسزیک بر کاهش اثرات سوء تنش گرمای دوره زایشی بر رشد، عملکرد و اجزای عملکرد گندم (رقم فونگ و چمران)، طی سال زراعی 1395-1396، به صورت کرت های دو بار خردشده در قالب طرح پایه بلوک کامل تصادفی با سه تکرار در مزرعه آزمایشی دانشگاه شهید چمران اهواز اجرا شد. تنش گرما با توجه به برآورد 30 ساله دمای محیط و بر اساس تاریخ کاشت لحاظ گردید. در این آزمایش سه عامل محلول پاشی شامل شاهد (عدم محلول پاشی)، اسید آبسزیک (30 میلی گرم در لیتر) و اسید سالیسیلیک (69 میلی گرم در لیتر) و زمان کاربرد ترکیبات شیمیایی مختلف شامل 15 روز قبل از گلدهی، گلدهی، 15 روز پس از گلدهی و محلول پاشی در سه زمان 15 روز قبل از گلدهی، گلدهی و 15 روز پس از گلدهی و ارقام گندم فونگ و چمران، مورد بررسی قرار گرفتند. نتایج نشان داد که محلول پاشی سبب افزایش تعداد دانه در بوته (اسید سالیسیلیک با متوسط 94/5و اسید آبسزیک با متوسط 4/86 دانه در بوته) در مقایسه با تیمار شاهد (با متوسط 75 دانه در بوته) شد که افزایش وزن دانه را به دنبال داشت. با توجه به نتایج صفات وزن دانه در بوته (4/0گرم در بوته)، وزن هزار دانه (41/2 گرم) و شاخص برداشت (49/6 درصد) به نظر می رسد که محلول پاشی اسید سالیسیلیک 69 میلی گرم بر لیتر در زمان گلدهی و دو هفته قبل و پس از آن در رقم چمران در استان خوزستان و مناطقی با شرایط مشابه، مناسب باشد.
    کلیدواژگان: اسید آبسزیک، اسید سالیسیلیک، شاخص برداشت، وزن دانه در بوته
  • محمد یزدان دوست، مختار قبادی*، محمداقبال قبادی، سعید جلالی، محسن سعیدی صفحات 477-489
    این مطالعه با هدف بررسی اثر محلول‏پاشی برخی ترکیبات شیمیایی و رژیم های آبیاری بر تبادلات گازی، خصوصیات فتوسنتزی و روابط آبی آفتابگردان انجام گرفت. آزمایش به صورت کرت های خرد شده بر پایه بلوک های کامل تصادفی در سه تکرار در مرکز تحقیقات و آموزش کشاورزی و منابع طبیعی همدان به مدت دو سال اجرا شد. تیمارهای آبیاری شامل 100، 80 و 60 درصد نیاز آبی گیاه و تیمارهای محلول پاشی شامل: آبسیزیک اسید، سلنیوم، سالیسیلیک اسید، سدیم نیتروپروساید، گلیسین بتائین و شاهد بودند. نتایج نشان داد که با کاهش میزان آبیاری، ویژگی‏های هدایت روزنه ای، سرعت تعرق، محتوای نسبی آب برگ و سرعت فتوسنتز کاهش یافتند، اما دمای برگ افزایش یافت. غلظت CO2 زیر روزنه در ابتدا کاهش و در ادامه با تشدید کم آبی افزایش یافت، با این حال، کارآیی مصرف آب فتوسنتزی به طور یکنواخت روند افزایشی داشت. محلول پاشی با ترکیبات شیمیایی، تبادلات گازی و خصوصیات فتوسنتزی آفتابگردان را تحت تاثیر قرار داد. کمترین میزان هدایت روزنه ای و تعرق و بیشترین میزان محتوای نسبی آب برگ در نتیجه محلول پاشی با آبسیزیک اسید و سدیم نیتروپروساید به دست آمد و بیشترین دمای برگ ناشی از کاربرد آبسیزیک اسید بود. اثر متقابل آبیاری × محلول پاشی بر سرعت فتوسنتز و غلظت CO2 زیر روزنه معنی دار بود. در شرایط کم آبیاری، کاربرد ترکیبات شیمیایی مورد نظر، سرعت فتوسنتز را نسبت به تیمار شاهد افزایش و غلظت CO2 زیر روزنه را کاهش داد. در این مورد، سالیسیلیک اسید نسبت به سایر ترکیبات، اثر بیشتری داشت و در شرایط کم آبی شدید (60 درصد نیاز آبی)، باعث افزایش 19/6 درصد در سرعت فتوسنتز گردید.
    کلیدواژگان: آبسیزیک اسید، سالیسیلیک اسید، سدیم نیتروپروساید، سلنیوم، گلیسین بتائین
  • فرشاد صالحی، افراسیاب راهنما *، موسی مسکرباشی، خسرو مهدی خانلو صفحات 491-502
    تنش گرما یکی از تنش های غیرزیستی مهم در مناطق گرمسیری و نیمه گرمسیری است که به شدت، رشد و عملکرد گیاهان زراعی را کاهش می دهد. به منظور بررسی واکنش رشدی و عملکردی ارقام گلرنگ زراعی به تنش گرمای آخر فصل، پژوهشی به صورت کرت های یک بار خردشده در قالب طرح بلوک های کامل تصادفی با سه تکرار در سال زراعی 97- 1396 در مزرعه آزمایشی دانشگاه شهید چمران اهواز، اجرا شد. تنش گرما به صورت تاخیر در تاریخ کاشت و هم زمانی مراحل رشد زایشی با تنش گرمای آخر فصل در نظر گرفته شد. کرت های اصلی این آزمایش شامل سه تاریخ کاشت 20 آذر، 10 دی و 30 دی (به ترتیب تاریخ کاشت به هنگام، تاخیری و دیرهنگام) و کرت های فرعی شامل چهار رقم گلرنگ زراعی (گلدشت، پرنیان، صفه و فرامان) بود. تنش گرما سبب کاهش معنی دار عملکرد زیست توده، عملکرد دانه و فعالیت آنزیمی کاتالاز و افزایش شاخص برداشت، غلظت کلروفیل کل برگ و فعالیت آنزیم پراکسیداز شد، اگرچه واکنش ارقام متفاوت بود. بیشترین میزان عملکرد دانه و زیست توده مربوط به رقم فرامان در شرایط شاهد به ترتیب با میانگین 4151 و 23352 کیلوگرم در هکتار بود. وقوع تنش گرمای آخر فصل منجر به کاهش معنی دار عملکرد دانه ارقام صفه، پرنیان، فرامان و گلدشت به ترتیب به میزان 53، 44، 60 و 47 درصد در تاریخ کاشت 30 دی نسبت به تاریخ کاشت 20 آذر شد که این میزان به ترتیب برابر با 1/32، 1/1، 1/5 و 1/17 درصد به ازای هر روز تاخیر در تاریخ کاشت بود. براساس شاخص حساسیت به تنش (SSI)، ارقام پرنیان و گلدشت با مقادیر 0/85 و 0/92 از تحمل بالایی برخوردار بودند؛ در حالی که ارقام فرامان و صفه با شاخص 1/16 و 1/03 حساسیت زیادی نسبت به تنش داشتند. به طور کلی نتایج این پژوهش نشان داد که در صورت تاخیر در تاریخ کاشت، توصیه می شود که از رقم گلدشت استفاده شود، چرا که عملکرد دانه و روغن آن نسبت به سایر ارقام برتری قابل توجهی در تاریخ های مختلف کاشت داشت.
    کلیدواژگان: آنزیم های آنتی اکسیدان، تنش گرمایی، درصد روغن، عملکرد دانه
  • حمیدرضا مبصر، بنیامین ترابی، حسین عجم، نورالله خیری* صفحات 503-515
    به منظور بررسی اثر سیلیس و روی به دو فرم محلول پاشی (منبع نانوذرات) و خاک -مصرف (منبع معمولی) در قالب تیمارهای انفرادی یا ترکیبی بر صفات زراعی و فیزیولوژیکی برنج (Oryza sativa L.)، آزمایش مزرعه ای به صورت طرح بلوک های کامل تصادفی با 16 تیمار و سه تکرار در دو منطقه از استان مازندران (آمل و نور) در سال 1395 اجرا شد. نتایج نشان داد که اجزای عملکرد، عملکرد و هم چنین غلظت و جذب سیلیس و روی در دانه برنج با کاربرد سیلیس و روی به هر دو روش محلول پاشی نانو ذرات و خاک- مصرف به طور معنی داری در مقایسه با شاهد افزایش یافت. کاربرد ترکیبی سیلیس و روی به صورت خاک-مصرف برتری معنی داری نسبت به مصرف جداگانه هر دو عنصر مورد استفاده در آزمایش از نظر تعداد پنجه بارور در کپه در منطقه آمل و تعداد دانه های پر در خوشه در منطقه نور داشت. از نظر محلول پاشی نانوذرات، کاربرد ترکیبی سیلیس و روی برتر از استفاده جداگانه سیلیس از نظر تعداد پنجه بارور در هر دو مکان آزمایش و میزان غلظت و جذب روی در دانه برنج بود. بنابراین با توجه به نتایج تحقیق حاضر، استفاده از سیلیس و روی به هر دو روش محلول پاشی نانوذرات و خاک- مصرف جهت افزایش غلظت و جذب این عناصر و هم چنین بهبود عملکرد دانه برنج در خاک هایی که قابلیت دسترسی پایینی به این دو عنصر غذایی دارند موثر می باشد.
    کلیدواژگان: روش مصرف، عملکرد دانه، منبع مصرف، نانوکود، جذب عناصر
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  • Amir Lakzian* Pages 359-372
    Introduction
    Excessive application of chemical fertilizers can lead to poor soil and groundwater quality and severe nutritional disturbances on the land and environmental damage. In recent years, increasing concern about the production of healthy food and the emphasis on maintaining fertility and soil quality have led to more attention to maintaining and increasing soil organic matter through appropriate management practices. Management of crop residues can play pivotal role in improving soil productivity and quality as well as crop yield through its effects on soil physical, chemical and biological properties. Soil quality, generally, indicates the ability of the soil to function as an ecosystem by preserving fertility, environmental quality and enhancing the health of plants and creatures which is always under the influence of management operations. Hence, soil quality assessment methods allow quantitative biological, chemical and physical responses of soil to be compared to different management practices. Soil quality assessment is a very complicated process due to the different soil properties in different management conditions.
    Materials and Methods
    To investigate the effect of various managements of wheat and sugar beet residues on some chemical and biological properties of soil, two distinct experiments were carried out in a completely randomized design with three replications. Treatments of first experiment included control (CW), wheat residues retained on soil surface (W), wheat residues incorporated into soil with plowing (PW), wheat residues incorporated into soil with plowing plus urea fertilizer (PFW), wheat residues burnt (BW) and wheat residues burnt is followed by incorporating into soil with plowing (PBW). Treatments of second experiment were including control (CS), sugar beet residues retained on soil surface (S), sugar beet residues incorporated into soil with plowing (PS) and sugar beet residues incorporated into soil with plowing plus urea fertilizer (PFS). In W and S treatments, the remained plants were distributed uniformly throughout the plot. In PW and PS treatments, the remained plants were mixed with soil by plowing to a depth of 30 cm. In PFW and PFS treatments, plant residues with urea fertilizer (4 tons per hectare) were added to soil surface and then plowed. In BW treatment, wheat plant residues were distributed uniformly in plot and then the burning was performed manually. In BPW treatment, plant residues were mixed with soil after burning by plowing. After applying the experimental treatments, all plots were irrigated in the same way. Irrigation intervals were applied to the plots similar to the adjacent plots and were irrigated regularly during the experiment period. After 6 months of application of the treatments, sampling of the treatments was carried out using a systematic method, consisting of plowing depth (0 to 25 centimeters of soil).
    Results and Discussion
    Results showed that various managements of wheat and sugar beet residues caused significant changes in studied chemical (except pH) and biological properties. All management methods, except retention of residues on soil surface (C and S treatments), increased organic carbon, total nitrogen, available phosphorus and potassium compared with the control treatment. Generally, in both crop residues, the greatest content of organic carbon, total nitrogen and available potassium were related to incorporating residues into soil with plowing plus urea fertilizer (PFW and PFS treatments). Also, the highest content of available phosphorus was related to PBW and PFS treatments in wheat and sugar beet residues management, respectively. In the case of basal microbial respiration and microbial biomass carbon, the most effective managements were residues incorporation into soil with plowing (PW and PS treatments) and then residues incorporation into soil with plowing plus urea fertilizer (PFW and PFS treatments). In this study, although residues burning (BW and PBW treatments) improved nutrient content, microbial respiration and microbial biomass carbon compared with the control treatment, they were less effective than PW and PFW treatments. According to the results, in both wheat and sugar beet residues, the most appropriate managements to improve the soil quality indicators were to incorporate the residues into soil with plowing plus urea fertilizer, as well as only incorporating the residues into soil with plowing. The results showed that the use of a minimum set of properties affecting soil quality or MDS can determine the soil quality with reasonable accuracy and cost and time less in the studied soil.
    Keywords: Nutrient elements, Residue burning, Residues incorporation
  • Parviz Rezvani* Pages 373-387
    Introduction
    Nowadays, need for medicinal plants are increasing to the extent that it has become a very important in terms of trade. Chinese lantern belongs to Solanaceae family and it is indigenous to the American continent. There are many benefits to Chinese lantern such as anticancer activities against hepatitis and Diabetes. The optimum planting date of Chinese lantern is one the most important factors for a successful cultivation. Interactions between environmental and plant factors cause planting date, transplanting date and the age of the transplants vary from one location to another, even among different genotypes. Moreover, the optimum plant density is an essential factor to reach a high yield. In fact, low plant density leads sources to waste; on the other side, high plant density causes yield reduction due to intense competition. The present study aims to investigate the effects of different plant densities and age of transplants on yield and yield components of Chinese lantern in Mashhad, Iran.
    Materials and Methods
    A field study in a factorial experiment based on a randomized complete block design was carried out with three replications at the research field of faculty of agriculture, Ferdowsi University of Mashhad, Iran in 2016. The experimental treatments were the combination of transplants age (5, 8 and 11 weeks) and four levels of the plant density (5, 6.7, 10 and 20 plants per square meter). All the transplants were transferred in the field on May 5. Plots were designed with 3 m long and 2 m width, 0.5 m apart from each other. The first irrigation was done three days before transplanting date; and further irrigation was done immediately after transplanting. At the maturity stage, five plants in each plot were selected randomly to measure plant height, fruit number, fruit weight per plant, single fruit weight, the number of seeds per fruit and 1000 seeds weight. Final fruit yield, biological yields and harvest index were measured by harvesting 1 m2 of the central part of each plot. All data were subjected to analysis of variance (ANOVA) using SAS 9.1 software (SAS, 2011). When F test indicated statistical significance at p<0.01 or p<0.05, the least significant difference (LSD) was used to separate the means.
    Results and Discussion
    The highest fruit weight per plant was acquired by the density of 5 plants per m2 and transplant age of 8 and 11 weeks. Increasing plant density from 5 to 20 per m2 led to decrease fruit weight in plant. In the low density, plants can access to the sufficient amount of recourses, so, yield rises; while in the high density, plant competition causes assimilation to reduce. The highest biological yield (16 tons per hectare) was obtained in the 8- and 11-week transplants, and density of 20 plants per m2. The highest fruit yield was achieved at 10 plants per m2 and 11-week-old transplant which was significantly different from the other treatments. The highest fruit yield was obtained by the density of 10 plants per m2 followed by 6.7 plants per m2 when 8-weeks transplant was used. The 11-week-old transplant and the density of 5 plants per m2 produced the highest fruit number (109). In general, with increasing age of transplants, the number of seeds per fruit increased. The results showed that increasing age of transplants from 5 to 11 weeks led to increase seeds weight from 2.14 g to 2.87 g. Plant height increased significantly by increasing plant density. The density of 5, 6.7 and 10 plants per m2, and 8 and 11 weeks old transplants had the highest harvest index. The lowest harvest index was seen at 20 plants per m2. Overall, 5-week-old transplants could not produce proper mature plants; also, the density of 20 plants per m2 was not favorite for most of the traits except for biological mass and plant height.
    Conclusions
    The results showed that plant density and the age of transplants had significant effects on the studied traits. All the traits were superior when 8- and 11-week old transplants were used. It seems that 5-week-old seedlings were not enough strong to grow well and did not have a normal plant size to provide successful mature plants in the field. Plant height and biological mass increased when plant density increased.
    Keywords: Biological yield, Fruit yield, Harvest index, Plant height, 1000 seeds weight
  • Mahmoud Khorramivafa* Pages 389-401
    Introduction
    Intercropping is one of the suitable management methods in crops production that improves absorption and use efficiency of resources by plants. Higher production in intercropping systems compared to sole cropping systems is attributed to morphological differences and different needs of the plants to utilize of environmental resources such as light, water and nutrients. There are the adequate logical and reasonable grounds to intercropping of potato and sweet corn because of their economic importance and physiological and morphological differences. Furthermore, harvesting of these crops had not any disorder. While, access to information such as resources use efficiency is need to find the best intercropping combination. Then the objective of this study was evaluation of radiation absorption and use efficiency (RUE) of sweet corn (Zea mays. Var. saccharata) intercropped with potato (Solanum tuberosum) under Kermanshah climate condition.
    Materials and Methods
    The experiment was conducted based on a randomized complete block design with three replications in the research farm of campus of agriculture and natural resources, Razi University, Kermanshah, Iran during the growing season of 2013. Treatments were included the intercropping of sweet corn (Chase) and potato (Agria) with 1:1, 2:2, 2:1, 1:2 ratios (that shows the sweet corn and potato rows, respectively) along with sole cropping of sweet corn and potatoes. Planting intra rows spacing were 13 and 25 cm for sweet corn and potato respectively. Planting inter rows were 75 cm with 7 m long for both crops. The destruction sampling was done at two weeks after emergence. In every stage, three plants were selected from each plot randomly. Absorbed radiation was calculated by simulated entrance radiation and absorbed radiation percent multiply: and cumulative total absorbed radiation was obtained by simulated entrance radiation× integral of absorbed daily radiation to time ratio. Ultimately, RUE of sweet corn and potato was evaluated as g MJ-1 by linear regression slope between total accumulative dry mater (g m-2) and accumulative daily radiation (MJ m-2) for each plot individually.
    Results and Discussion
    Results showed that leaf area index (LAI) was higher in all intercropping treatments than sole cropping. Among intercropping patterns, the highest and lowest LAI were observed in 2 rows sweet corn + 1 row potato (4.12) and 1 row sweet corn + 2 rows potato (3.4), respectively. Also dry mater accumulation trend was affected by intercropping patterns and radiation absorption increased by sweet corn and potato canopy appropriate to LAI rising. RUE of sweet corn and potato in intercropping was higher than of sole cropping. Among different intercropping patterns, the highest amount of sweet corn RUE were 2.18 and 1.86 g MJ-1 ,respectively that obtained in intercropping of 1 row sweet corn +2 rows potato. The highest sweet corn shelled kernel for conserving (3300 kg ha-1) and potato yield (9460 k ha-1) were obtained in 2 row sweet corn + 1 rows potato and 2 row sweet corn + 2 rows potato, respectively. On the contrary, increasing the number of potato rows resulted in higher RUE. Results also showed that land equivalent ratios were bigger than 1 in all intercropping patterns. Pattern of 2 rows sweet corn + 1 row potato, was recommended with the highest LER (1.41) economically. The additional obtained yield can attribute to better radiation use because of the morphological and physiological differences between sweet corn and potato. There was no considerable dissimilarity in dry matter accumulation trend between intercropping of sweet corn with potato and their sole cropping because of little plants in early growth season. However, the dry mater trend continued as linear stage at 30 days after sowing date as the differences were appeared between intercropping and sole cropping plots.
    Conclusions
    Compared to sole cropping, results of present study showed that the intercropping of sweet corn and potato resulted in LAI improvement, dry matter rising, more efficiency in radiation absorption and increasing of radiation use efficiency. Also this intercropping is recommended economically based on obtained LERs. Therefore, this study suggests the intercropping of 2 rows sweet corn + 2 rows potato economically. However, the water consumption and water use efficiency must be investigated to choose the best intercropping pattern.
    Keywords: Cultivation pattern, Productivity, Resources use efficiency
  • Mohammad Kafi* Pages 403-414
    Introduction
    Severe water shortage is one of the major challenges of agricultural sector in arid and semi-arid region. Optimal use of water resources, along with improving the efficiency of nutrient elements under drought conditions, will increase or stabilize crop yield. Forage production using plant species with low water requirement and adapted to low quality waters is a sustainable strategy for fodder production in dry areas. Blue panic grass (Panicum antidotale Retz.) is a halophytic crop plant, which is water productive and adapted to tropical conditions. This study was carried out to investigate the effects of drought stress, nitrogen and potassium on some physiological characteristics and dry matter yield of blue panic grass in Birjand, South-Khorasan province of Iran.
     
    Materials and Methods
    This study was conducted as a split-factorial experiment with three replications using a randomized complete block design at the Research Field of Islamic Azad University of Birjand. Irrigation was considered as the main factor at three levels based on cumulative evaporation from evaporation pan class A (70, 140 and 210 mm), nitrogen fertilizer was applied in three levels based on soil test including zero, 50% (100 kg ha-1) and 100% (200 kg ha-1) of recommended N. Potassium was applied in two levels (zero and 100 kg ha-1). Blue panic grass is perennial and in the first year, most of the photosynthetic assimilate are being used for the establishment of the plant; Hence, treatments were imposed in the second year of the experiment. During the growing season, radiation use efficiency and water use efficiency calculated three times during the growing season. Dry matter accumulation was measured at the final harvest. In addition, nitrogen use efficiency and agronomic nitrogen efficiency were calculated based on the consumed nitrogen fertilizer during the growing season and total dry matter harvested during the growing season.
     
    Results and Discussion
    Results showed that under water stress conditions the radiation use efficiency decreased, while, water use efficiency increased. We concluded that providing enough water and nutrients can increase dry matter production and radiation use efficiency. Application of nitrogen and potassium fertilizers under severe water stress conditions led to an increasing water use efficiency. Application of higher levels of nitrogen reduced nitrogen use efficiency.
     
    Conclusions
    Blue panic grass showed good performance under water stress conditions. Results indicated that application of nitrogen and potassium fertilizers under water stress conditions could mitigate the adverse effects of drought stress and increase nitrogen and water use efficiency.
    Keywords: Drought stress, Nutrient elements, Water use efficiency
  • Zahra Taghipour* Pages 415-425
    Introduction
    Drought stress is the most important and common environmental stress that annually bring huge damage to crops in the world and especially in Iran, which is considered as an arid and semi-arid country. Nowadays, most plants breeding plans for resistance against drought and preparing resistant species are to achieve favorable yield in arid environments and are based on recognizing morpho-physiological and biochemical traits and involved genes and transforming them to cultivars. There is a genetic diversity regarding resistance against aridity among Aegilops species that can be used to improve resistance against aridity in wheat during different stages of reproduction and plant growth.
    Materials and Methods
    This investigation was performed in green house of Agricultural Faculty in University of Mohaghegh Ardabili on 2011 in order to survey the effects of aridity stress and study the traits related to resistance in eight ecotypes of Aegilops triuncialis (ecotypes of Maku, Marand, Hashtrud, Namin, Hurand, Karaj, Meshkin and Ahar). The experiment was performed in three replications as factorial and based on completely randomized design. Different stages of irrigation including full irrigation as control, cutting of irrigation from booting (T1), (zadoks stage 45) and from 50% spike emergence (T2) (zadoks stage 55) to maturity were considered as water stress levels. Studied morphological traits include plant height (cm), plant dry weight (g), peduncle length (cm), spike length (cm), number of grains in spike, weight of grains per spike (g), 100 grain weight (g), spike dry weigh (g), root length and root mass. Chlorophyll content was measured by SPAD-502 machine. In order to measure fluorescence content of chlorophyll, OSI 30 machine of ADC Bioscietific Company and to measure stomatal conductance leaf porometer (SC-1 model) were used. Data analysis was performed by SAS ver.9.1 software and cutting was done in case of significant interactive effect. Mean comparison was done by Lsmeans test at probability level of 5%.
    Results and Discussion
    Water stress decreased all evaluated traits especially grain yield (89%). Water stress condition, by damaging photosynthesis system, reduced photochemical efficiency of PS II and chlorophyll index. Stomatal conductance rate reduced by 46% at booting stage and 55% at spike emergence and also decreased relative water content by 26% compared to normal circumstances. Although drought stress application in the experiment decreased grain yield in ecotypes compared to no stress conditions, some ecotypes like Hashtrud, Hurand and Maku could resist stress conditions and showed less grain yield decrease in comparison to the others. Ecotypes of Hashtrud, Marand, Meshkin could supply their necessary moisture from deep soil by increasing their root length. Ecotypes with higher ratio of Fv/Fm and less chlorophyll index decrease under stress condition could have less grain yield decrease. It seems that superiority of Hashtrud, Hurand and Maku ecotypes in stress conditions compared to other ecotypes could be due to these characteristics.
    Conclusions
    Terminal drought results in reduced growth period, length, peduncle length, main panicle length and also reduced grain yield. Drought stress by damaging photosynthesis system and decreased photosynthesis and chlorophyll and limiting photosynthesis allocations of grains under stress condition decreases their weight and finally their yield.
    Keywords: Drought stress, Fluorescence chlorophyll, Grain yield, stomatal conductance
  • Sarvar Khoramdel* Pages 427-439
    Introduction
    Sesame (Sesamum indicum L.) is known as the king of oil seeds due to the high oil content (50-60%) of its seed. Nitrogen (N) is one of the most important nutrients in crop production systems. Excessive use of N in crop production causes a declining trend in nitrogen use efficiency (NUE). It has been reported that not more than 33% of N applied is used by the plant, while the remainder is lost and causes environmental pollution as well as emission of greenhouse. Optimization of nitrogen and plant density is a management approach to conserve resources and decline environmental pollutions. Response surface methodology (RSM) is defined as a set of mathematical and statistical techniques that are used to develop, to improve or to optimize a product. RSM is a statistical method for optimization of multiple factors which determine optimum process conditions by combining experimental designs. In this work, optimization of nitrogen fertilizer and plant density of sesame using central composite design for Response surface methodology was done.
     
    Materials and Methods
    This research was conducted using central composite design with 13 treatments and two replications at the Research Field of Ferdowsi University of Mashhad during the growing season of 2015-2016. The treatments were allocated based on low and high levels of plant density (10 and 40 plants.m-2, respectively) and nitrogen (0 and 100 kg Urea ha-1, respectively). Plant height, yield components, seed yield, biological yield, harvest index, oil percentage, oil yield, protein percentage and, protein yield were calculated as dependent variables and changes of these variables were evaluated by a regression model. Lack-of-fit test was used to evaluate the quality of the fitted model. The adequacy of the model was tested by analysis of variance. In general, the full quadratic polynomial equation was tested to determine the significance of the model and the component of the model (linear, squared, first-order interaction terms). The quality of the fitted model was judged using the determination coefficient (R2).
     
    Results and Discussion
    The results showed that effect of linear component was significant on all studied characteristics. Effect of square component was significant on all studied criteria except harvest index, seed No. per capsule and 1000-seed weight. Interaction effect of full quadratic was significant on plant height, seed No. per plant and protein percentage. Lack of fit test had no significant effect on the studied traits. The full square model for the response variables gave insignificant lack-of-fit indicating that the data of experimental were satisfactorily explained. The highest estimated and observed values of seed yield were obtained for 25 plants.m-2 and 50 kg Urea ha-1 and 25 plants.m-2 and 100 kg Urea ha-1 with 1320.5 and 1272.4 kg.ha-1, respectively. The highest estimated values of oil percentage and protein percentage were obtained for 10 plants.m-2 and without Urea application (46. 7%) and 40 plants.m-2 and 100 kg Urea ha-1 kg Urea ha-1 (25.3%) and these maximum observed amounts were recorded in 10 plants.m-2 and without Urea application (46.5%) and 40 plants.m-2 and 100 kg Urea ha-1 kg Urea ha-1 (25.0%), respectively.
     
    Conclusions
    The slope of seed yield increased by an increase in density up to 25 plants.m-2 and was higher under high levels of N fertilizer (optimum level= 50 kg Urea ha-1) than under low levels, because the plant growth was improved in high amount of N fertilizer and resulted in high yield components and seed yield. Therefore, the effect of plant density on yield improvement could be increased at high levels of N fertilizer which clearly suggest the importance of N for higher seed production in sesame. In general, it seems that resource use optimization based on the central composite design may be suitable cropping approach for sustainable production of sesame.
     Acknowledgement

    This research was funded by Vice Chancellor for Research of Ferdowsi University of Mashhad, which is hereby acknowledged.
    Keywords: Lack-of-fit test, Response surface methodology, Sustainable production
  • Hamidreza Esvand* Pages 441-455
    Introduction
    Wheat (Triticum aestivum L.) is one of the most important sources of plant food for human among the main crops globally. High temperature resulting from delay in planting is one major environmental factor limiting growth and production of wheat, especially in tropical regions. Most of the Iranian soils have high pH and calcareous nature, so absorption of nutrients is limited in these soils. Mineral nutrition of plants plays a critical role in increasing plant resistance to environmental stresses. Among the mineral nutrients, potassium plays a crucial role in the survival of crop plants under environmental stress conditions. Potassium is essential for many physiological processes, such as photosynthesis, maintenance of turgidity and activation of enzymes under stress conditions. Zinc is a ubiquitous micronutrient. It is required as a structural and functional component of many enzymes and proteins.
    Materials and Methods
    To study the effect of potassium and zinc foliar application on growth physiological indices, chlorophyll fluorescence parameters and yield of two bread wheat cultivars under late planting date, an experiment was conducted as split-split plot based on randomized complete blocks design with 16 treatments and three replications in Ramhormoz city during 2015-2016. The experimental factors were included planting date in two levels optimum (November 21) and late (January 5) as the main factor, nutrients foliar application in four levels (water as a control, potassium, zinc and combination potassium + zinc (each 3 l.ha-1)) as the sub factor and two cultivars of bread wheat Pishtaz and Chamran 2 as the sub-sub factor. Solutions for foliar application were prepared by using potassium (21%) and zinc-chelate (7.5%). Traits measured were included leaf area index (LAI), leaf area duration (LAD), crop growth rate (CGR), relative growth rate (RGR), net assimilation ratio (NAR), maximal quantum yield of PSII in the dark-adapted state (Fv/Fm), effective quantum yield of PSII photochemistry (ΦPSII), maximal quantum yield of PSII in the light-adapted state (Fv'/Fm'), nonphotochemical quenching (NPQ) and grain yield. To determine LAI, LAD, CGR, RGR, NAR, Fv/Fm, ΦPSII, Fv'/Fm' and NPQ were used from equations 1-9, respectively.
     LAI= Pla×den /10000
     LAD= 1/2 (LA2+LA1) (T2-T1) 
     CGR= [(W2 – W1)/(T2 – T1)] × (1/GA) × 100
     RGR= [(lnW2 – lnW1)/( T2 – T1)] × 100
     NAR= CGR/LAI
     Fv/Fm= (Fm – F0)/Fm
     ΦPSII= (Fm – Ft)/Fm'
     Fv'/Fm'= (Fm' –F0')/Fm'
     NPQ= (Fm – Fm')/Fm'
    where, Pla is average leaf area per plant (cm2); den is real density (plant m-2); LA1 is primary leaf area (cm2); LA2 is secondary leaf area (cm2); T1 is first sampling time (day); T2 is second sampling time (day); W1 is primary dry weight (g); W2 is secondary dry weight (g); GA is ground area (m2); lnW2 – lnW1 is natural logarithm difference of dry weight; Fm is maximal fluorescence yield of the dark-adapted state; F0 is minimal fluorescence yield of the dark-adapted state; Fv is variable fluorescence (dark) (Fm-F0); Ft is fluorescence emitted by the leaves adapted to lighting; Fm' is maximal fluorescence yield of the light-adapted state; F0'is minimal fluorescence yield of the light-adapted state, and Fv' is variable fluorescence (light) (Fm'-F0'). The grain yield was determined at maturity stage and through the harvest of all spikes from the level of 1 m2 per plot and after removing 0.5 m from the beginning and end respective planting rows (rows 5 and 6).Analysis of variance was performed using general linear model (GLM) procedure of statistical analysis system (SAS version: 9.3). The means were analyzed using the least significant difference (LSD) method at P=0.05 (LSD 0.05).
    Results and Discussion
    The results showed that late planting date due to terminal heat stress significantly decreased LAI (30.0%), LAD (48.4%), CGR (21.8%), RGR (13.7%), NAR (22.4%), Fv/Fm (3.2%), ΦPSII (4.4%), Fv'/Fm' (3.2%) and grain yield (27.0%) of two cultivars of bread wheat Pishtaz and Chamran 2, but increased significantly the NPQ (22.7%). Potassium and zinc foliar application improved significantly traits the LAI (17.5%), LAD (17.62%), CGR (33.5%), RGR (12.0%), NAR (37.6%), Fv/Fm (3.1%), ΦPSII (7.4%), Fv'/Fm' (6.6%) and grain yield (17.30%) of two cultivars of bread wheat Pishtaz and Chamran 2 under late planting date except for the NPQ. Among the interactions of nutrients foliar application and bread wheat cultivars, the response of Pishtaz and Chamran 2 cultivars were more suitable to potassium foliar application, and zinc and zinc + potassium foliar application, respectively. As well as, among wheat cultivars cultivated under the conditions of non-application of potassium and zinc (control), Chamran 2 cultivar had a comparative advantage in all measured traits under both optimum and late planting dates compared to Pishtaz cultivar.
    Conclusions
    In general, it can be used from timely planting date, potassium and zinc foliar application and suitable wheat cultivar such as Chamran 2 as three management strategies to reduce the harmful effects of terminal heat stress caused by late planting date in Ramhormoz city.
    Keywords: Cereals, Nutrients, Terminal heat stress
  • Vahid Mohasseli* Pages 457-465
    Introduction
    Iron deficiency is found mainly in plants in calcareous and alkaline soils. Regarding the fact that chemical conditions of the soils are main cause of iron chlorosis, and because of chalet fertilizers are expensive therefore, use of organic and iron-rich organic compounds such as blood powder can be effective in removal of iron chlorosis. Blood can have a beneficial effect on more dissolution of iron compounds. One kg of blood contains 20-30 g iron in ferrous form (Fe2+) in hemoglobin molecule. Therefore, it can use as an effective source of iron. Blood powder is only organic fertilizers containing nitrogen, iron, phosphorus, organic complexes and amino acids useful hormones in plants growth. The process of iron liberation from Blood powder is carried out more rapidly in calcareous soils. Further, decomposition of it reduces soil reaction. Iron is chalet form in Blood which it makes to protect Fe from chemical reactions and conversation into non available forms. Therefore, the purpose of this study was to investigate potential of blood powder in supplying iron of Melissa Officinalis L.
    Materials and Methods
    The experiment was performed as factorial in a completely randomized design with three levels of Fe-EDDHA (Zero , 2.5 and 5 mg Fe kg-1 soil) and 4 levels of Blood powder (Zero, 0.75, 1.5 and 3 g blood powder kg-1 soil) in Three replication on Melissa Officinalis L. medicinal plant. There were measured dry weight, concentration of Fe, chlorophyll a and b, carotenoids and essential oil content after the end of vegetative growth period. 
    Results and Discussions
    The results showed that application of Fe-EDDHA and Blood powder increased significantly shoot dry weight, concentration of Fe, chlorophyll, carotenoids and essential oil yield in plant. The maximum of plant dry weight was 141.4 g.pot-1 under conditions of Fe EDDHA and Blood powder intake of 2.5 mg and 1.5 g kg-1 respectively, which it was equal to 22.5% higher than control. Consumption of 5 mg Fe and 3 g.kg-1 blood powder caused 35.1% increase in Fe concentration compared to control. Blood powder consumption increased 13.8, 6.8 and 11.7% in the first, second and third levels of iron, respectively. Chlorophyll b concentration was increased 17.2 and 23.0% by application of mg Fe and 3 g blood powder kg-1 soil, respectively. Concentration averages of carotenoids were 0.31, 0.32 and 0.35 mg.g-1 in the first, second and third levels of iron, respectively. But the averages were 0.31, 0.31, 0.35 and 33.3 mg.g-1 in the first to fourth levels of blood powder, respectively. The amount of essential oil was increased at all levels of iron and blood powder compared to control, which it was obtained 241. 7% increasing with compared to control by application of iron and blood powder of 5 mg and 3 g.kg-1, respectively. The same amount of iron and blood powder produced the maximum essential oil yield (304.5% higher compared to control).
    Conclusions
    In general, the results of the study showed that application of Fe-EDDHA and blood powder increased plant dry matter, iron, chlorophyll and carotenoids concentration and essential oil content of Melissa Officinalis L. However, at higher levels of these treatments, it caused a lower growth in growth and essential oil yield. Regarding the positive effect of iron intake on essential oil yield of Melissa Officinalis L. and on the other hand, considering the cost of iron organic fertilizers, the use of blood powder is recommended in the cultivation of the medicinal plant. Also, due to the lack of apparent symptoms of toxicity at high levels of iron thus, cultivation of Melissa plant is suggested in soils with a medium of Fe pollution. Although it seems more research is needed in this regard.
    Keywords: Amount, yield of essential oil, Dry weight, Iron, Organic compounds
  • Majid Nabipour* Pages 467-476
    Introduction
    Wheat is one of the most widely cultivated cereals in the world. Thermal stress is effective on photosynthesis, cellular and subcellular compounds, protein levels and antioxidant activity. The role of abscisic acid as an anti-stress hormone is easily proved. Abscisic acids cause stomatal closure and improve the plant's water relations. Salicylic acid, as a cell signal, increases the amount of defense compounds such as proline. Also, the use of salicylic acid increases the amount of polyphenols, spermidine and spermine in the plant, which can help stabilize the membrane under stress conditions. The present experiment was conducted to investigate the effect of foliar application with salicylic acid and abscisic acid on reducing the effects of terminal heat stress on the growth, yield and yield components of wheat (Fung and Chamran cultivars) in Ahvaz.
    Materials and Methods
    This experiment was conducted in a split split plot based on a randomized complete block design with three replications at the experimental farm of Shahid Chamran University of Ahvaz in 2016-2017. The experiment was directed in a potted (in field conditions) and heat stress was considered based on the planting date according to the 30-year estimate of ambient temperature and it’s higher than the threshold of thermal tolerance of the wheat plant. In this experiment, three factors were investigated: foliar application (control (no foliar application), foliar application with abscisic acid (30 mg.l-1), and foliar application with salicylic acid (69 mg.l-1)), time of foliar application (15 days before flowering (A), flowering (B), 15 days after flowering (C) and 15 days before flowering, flowering and 15 days after flowering (ABC)) and wheat cultivars (Fung and Chamran).
    Results and Discussion
    According to the results, with increasing number of spikelets per spike, the number of grains per spikelet increased and thus, the number of grains per spike increased. Foliar application increased the number of seeds per plant compared to control treatment, which increased the seed weight. The lowest plant height was obtained to treatment of foliar application of salicylic acid at flowering time on Fung cultivar. The highest and lowest spike length were observed in the control of Fong and foliar application of salicylic acid at flowering time and two weeks before and after than on Fung cultivar. The results of mean comparison of the traits showed that the highest mean spikelet number per spike belonged to foliar application of salicylic acid at two weeks after flowering in Chamran cultivar. The highest dry weight of shoot was observed in foliar application of salicylic acid at two weeks after flowering on Chamran cultivar.
    Conclusions
    According to the results, for traits such as dry weight of shoot, grain weight per plant and 1000 grain weight, foliar application at flowering and two weeks before and after that (regardless of cultivars and type of solution) was better compared to the other foliar application times. Foliar application at flowering and two weeks before and after that, improved the photosynthesis potential after spike emergence, improvement of meiosis of pollen mothers cells and increasing the fertility of spikes, reducing the abortion of the claws and increasing the number of seeds per spike under heat stress conditions. Chamran cultivar was recognized as superior to shoot dry weight and number of seeds per plant, in comparison to Fung cultivar (regardless of the time of foliar application and solution type). Salicylic acid with the highest number of seeds per plant, seed weight per plant, 1000 seed weight, dry weight of shoot and harvest index were determined as the best solution (regardless of the foliar application time and cultivar). Therefore it seems that in order to reduce the effects of terminal heat stress, using the salicylic acid (30 mg L-1) at flowering and two weeks before and after that on Chamran cultivar is appropriate in Khuzestan province and regions with similar conditions.
    Keywords: Abscisic acid, Salicylic acid, Harvest index, Grain weight per plant
  • Mokhtar Ghobadi* Pages 477-489
    Introduction
    Many solutions have been introduced to enhance drought tolerance. Exogenous applications of various chemicals such as compatible solutes, growth regulators and stress-messenger molecules have been considered during recent years. Glycine betaine (GB) is one of the most effective osmoprotectants. The physiological and antioxidant properties of selenium (SE) have become of higher importance for biologists. Salicylic acid (SA) plays an important role in the abiotic stresses tolerant. Nitric oxide plays an important role in many physiological and vegetative processes such as seed germination, stomatal closure, root development, aging and adaptation to several stress types. Sodium nitroprusside (SNP) is commonly used as a nitric oxide releasing agent in plants. Abscisic acid (ABA), as a messenger, plays a role in responding to drought and other environmental stresses, as well as in many physiological processes such as photosynthesis and regulation of stomatal opening and closure. The aim of this study was to compare the influence of some chemicals as foliar application in order to reduce the adverse effects of drought stress in sunflower.
    Materials and Methods
    This experiment was conducted at the Agricultural Research Center of Hamedan, Iran, during 2015-2016. Three irrigation and six foliar application treatments were evaluated in a split plot experiment. Irrigation treatments consisted of 60%, 80% and 100% of crop water requirement and foliar application treatments included: abscisic acid 40 M, Selenium 20 mg L-1, Salicylic acid 500 M, SNP 100 μM, Glycine betaine 100 mM, and control. An infrared gas analyzer (IRGA, Lci, ADC Biosientific Ltd, Hoddeston, UK) was used in order to measure the photosynthesis rate, stomatal conductance, transpiration rate, leaf temperature and sub-stomatal CO2 concentration. Photosynthetic water use efficiency was calculated from photosynthesis rate divided by transpiration rate. The leaf relative water content (RWC) was calculated as the follows:RWC (%) = [(FW - DW.) / (TW – DW)] × 100
    Where FW is the leaf fresh weight, DW is the leaf dry weight and TW indicates the leaf turgid weight.
    Combined analysis of variance of two years data was done using SAS statistical software. The comparison of means was carried out by Duncan's multiple range test at 5% of probability level.
    Results and Discussion
    Effects of irrigation and foliar application on stomatal conductivity and transpiration rate were significant. Stomatal conductivity and transpiration rate were decreased by decreasing irrigation amount. The lowest rate of stomatal conductivity and transpiration rate in all irrigation conditions were resulted from ABA. Leaf temperature and RWC were affected by irrigation and foliar application. The lowest leaf temperature was obtained under normal irrigation. The highest RWC (90.8%) was attributed to normal irrigation. Applying 80% and 60% of crop water requirement reduced RWC about 10% and 28.5%, respectively. Foliar application of chemicals increased RWC. The effects of irrigation and irrigation × foliar application on photosynthesis rate were significant. The photosynthesis rate decreased with decreasing the irrigation amount. Sub-stomatal CO2 concentration decreased under 80% of crop water requirement and it increased in 60% of crop water requirement. Under normal irrigation conditions, photosynthetic water use efficiency enhanced by foliar application of SA, but under water deficit conditions, foliar application with all compounds promoted photosynthetic water use efficiency.
    Conclusions
    Decreasing of irrigation water had significant effects on gas exchange and photosynthetic properties of sunflower and caused a sharp decline in stomatal conductance and transpiration rate. Furthermore, RWC and photosynthesis rate were decreased, but leaf temperature were increased simultaneously. By decreasing irrigation, the sub-stomatal CO2 concentration initially reduced and continued to increase with more water limitation, while the photosynthetic water use efficiency was increasing gradually. Foliar application with chemicals affected on gas exchange and photosynthetic properties of sunflower. The lowest stomatal conductance and transpiration rate, and the highest amount of RWC were obtained by foliar application of ABA and SNP. In normal irrigation, SA improved photosynthesis rate, but ABA, SNP and SE reduced the sub-stomatal CO2 concentration and photosynthetic rate. Under low irrigation, foliar application of all chemicals increased photosynthesis rate and reduced the sub-stomatal CO2 concentration. SA had a more positive impact rather than other compounds.
    Keywords: Abscisic acid, Glycine betaine, Salicylic acid, Selenium, Sodium nitroprusside
  • Afrasiab Rahnama Pages 491-502
    Introduction
    Terminal heat stress is a major abiotic stress especially in tropical and sub-tropical regions that severely reduces crop growth and yield. Safflower (Carthamus tinctorius L.) is an oilseed crop grown mainly for the production of high quality edible oil rich in polyunsaturated acids. This annual crop is native to a climate with a long dry season and a limited rainy season and compares to other annual crops has more resistance to drought stress. In addition, it's resistant to some diseases and susceptible to humidity. Since, to obtain the maximum yield of a crop, it is necessary to escape the development stages of (the/a) plant from unfavorable environmental factors and the full utilization of plant from favorable environmental conditions. Since the length of development stages more affected by temperature and day length, hence sowing date can be selected so that the different stages of plant growth were adapt with optimal temperature and day length. Yau (2006) indicated that later sowing of spring safflower in semi-arid and high elevation Mediterranean environment resulted in lower seed yield and later flowering does not allow an escape from the terminal drought and heat. Yau (2006) indicated that later sowing of spring safflower in semi-arid and high elevation Mediterranean environment resulted in lower seed yield and later flowering does not allow an escape from the terminal drought and heat. The aim of this study was to investigate the yield and yield components of safflower cultivars in response to different sowing data in Ahvaz.
    Materials and Methods
    In order to study the effect of sowing date on yield and yield components of safflower cultivars, this experiment was carried out as split plot layout based on randomized complete blocks design with three replications in at the research farm of Shahid Chamran University of Ahvaz in 2017-2018. The main factor included three levels of sowing date (11 Dec, 31 Dec and 20 Jan), and a sub factor including four cultivars of safflower (Goldasht, Parnian, Faraman and Sofeh). Data collected on all parameters were analyzed statistically using SAS software and mean comparison was carried out using Duncan test at the 5% of probability level. The studied traits included grain yield, biological yield, harvest index, oil yield, total chlorophyll concentration, catalase and peroxidase enzyme activity and stress susceptibility index.
    Results and Discussion
    A significant interaction was observed between the levels of sowing date and the cultivars in terms of plant height, weight of plant, biological yield and grain yield. Among the safflower cultivars, the highest weight per plant (143.3 g plant-1), biological yield (23352 kg ha-1), grain yield (4151.1 kg ha-1) and the lowest plant high (128.8 cm), was recorded in Faraman cultivar in sowing date of 11 December. In contrast, grain yield severely decreased in the 20 January sowing date with compared to the 11 December. So that, studied cultivars of Sofeh, Parnian, Faraman and Goldasht cultivar were decreased 53% (1277.3 kg ha-1), 44% (1668.9), 60% (1650.8) and 47% (1887.3), respectively. Under the heat stress, due to delayed planting date and decreased enzymatic activity of catalase, enzyme activity changed and the cultivars exposed to the terminal heat stress, but enzymatic activity of peroxidase increased. Stress susceptibility index (SSI), Parnian and Goldscht cultivars had a high tolerance with mean 0.85 and 0.92, while Faraman and Sofeh cultivars with an index of 1.16 and 1.03 had a high sensitivity to stress.
    Conclusions
    This research appears the delay in optimal planting date leads to synchronize the plant's reproductive stages with a high temperature at the end of the season. As a result, shorter plants, lower biological yield, lower grain and oil yield will be observed, however, the response of the cultivars from each other was different depend on their enzymatic capacity and the ability to maintain chlorophylls. Planting date should be selected such a way that this process does not a coincidence with terminal heat season. So, under hot weather conditions in Khuzestan, selecting the optimum planting date can be an appropriate solution to reduce the negative aspects of the terminal heat stress on the grain yield and component yield of different cultivars of safflower.
    Keywords: Antioxidant enzymes, Grain yield, Heat stress, Oil percentage
  • Norollah Kheyri* Pages 503-515
    Introduction
    Among the nutrients, silicon (Si) and zinc (Zn) play a key role in improving plant nutrition and increasing rice (Oryza sativa L.) growth, because their deficiency reduces growth and yield. Si, as one of the most abundant soil elements, helps to increase the amount of photosynthesis, improve performance, prevent lodging, and reduce pests and diseases. Zn is one of the most important micronutrients involved in protein synthesis and carbohydrate metabolism. One of the most important uses of nanotechnology in various aspects of agriculture in the water and soil section is the application of nano-fertilizers for plant nutrition. Nano-fertilizers can increase the nutrients use efficiency, improve plant growth and reduce environmental impacts compared to traditional methods. The purpose of this research was to evaluate the effect of Si and Zn by two forms of nanoparticles (NPs) foliar application and soil application in order to increasing the nutrient uptake efficiency and improving the rice grain yield.
     
    Materials and Methods
    This experiment was conducted as a randomized complete block design (RCBD) with 16 treatments and three replications in two locations of Mazandaran province (Amol and Nour) in 2016. The treatments included two forms of Si and Zn application: foliar application (nanoparticles source) and soil application (common source) as individually or mixtures treatments. For soil application, Si fertilizer was applied at the rate of 400 kg Ca2SiO4 ha-1 and Zn fertilizer at the rate of 40 kg ZnSO4 ha-1 as basal in experimental plots. Foliar application of nano-SiO2 and nano-ZnO in the concentration of 50 mg L-1 was applied at four plant growth stages (early tillering, middle tillering, panicle initiation and full heading stage) in plots. At the end of season, some yield components, grain yield as well as the concentrations and uptake of Si and Zn in grain were determined. The combined analysis of experimental data were done by using MSTAT-C software. The means were compared using the LSD test at 5% of probability level.
     
    Results and Discussion
    The results revealed that yield components, yield and concentration and uptake of experimental elements in rice grain were significantly increased by Si and Zn application in both methods of NPs foliar application and soil application compared to the control. In the case of soil application of the elements, combined use of Si and Zn was never statistically superior to use of only Zn in terms of yield, concentrations and uptake of test elements, but there was a significant difference in the sole application of Si in terms of panicle length and Zn concentration and uptake in rice grain. The combined application of Si and Zn as soil was statistically superior to the separate application of both elements in terms of fertile tillers per hill at Amol and filled grains per panicle at Nour site. In the case of NPs foliar application, combined use of Si and Zn was not statistically superior to use of only Zn in terms of yield and all other studied parameters, but superior to the separately use of Si for fertile tillers number in both experimental sites and Zn concentration and uptake in rice grains.
     
    Conclusions
    The Zn application had a better effect on Zn concentration and uptake in grain compared with Si, but there was no significant difference between Si and Zn application in terms of grain yield. There was no significant difference between the methods used in this experiment in terms of grain yield and concentration and uptake of Si and Zn in grain. Therefore, according to the results of this research, NPs foliar spray and soil application of Si and Zn is effective way for increasing concentration and uptake of test elements and as well as improving rice grain yield in soils having low-availability of these two nutrients.
    Keywords: Application method, Application source, Grain yield, Nanofertilizer, Elements uptake