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پژوهشهای زراعی ایران - سال چهاردهم شماره 2 (پیاپی 42، تابستان 1395)

نشریه پژوهشهای زراعی ایران
سال چهاردهم شماره 2 (پیاپی 42، تابستان 1395)

  • تاریخ انتشار: 1395/06/25
  • تعداد عناوین: 15
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  • علمی پژوهشی
  • مریم دباغ زاده، قدرت الله فتحی، عبدالمهدی بخشنده، خلیل عالمی سعید صفحات 215-225
    به منظور بررسی تاثیر تداخل علف های هرز و تراکم باقلا بر کنترل علف های هرز و عملکرد باقلا آزمایشی به صورت کرت های خرد شده در قالب طرح بلوک های کامل تصادفی با چهار تکرار در مزرعه پژوهشی دانشگاه کشاورزی و منابع طبیعی رامین اهواز در سال زراعی 89-1388 به مرحله اجرا درآمد. در این آزمایش تداخل علف های هرز در پنج سطح شامل: مراحل 5، 9 و 13 برگی گیاه باقلا، وجین تمام فصل علف های هرز و تداخل تمام فصل علف های هرز، در کرت های اصلی و تراکم باقلا در سه سطح 8، 11 و 14 بوته در مترمربع در کرت های فرعی مورد بررسی قرار گرفتند. نتایج نشان داد تداخل علف های هرز و تراکم باقلا اثر معنی داری روی تراکم علف های هرز، وزن خشک علف های هرز و عملکرد دانه باقلا داشتند. بیش ترین تراکم کل علف های هرز در تیمارهای تداخل، مربوط به تیمار 9 برگی و در تیمارهای تراکم باقلا مربوط به تیمار تراکم هشت بوته در متر مربع بود. با طولانی شدن دوره ی رقابت علف های هرز از آغاز فصل رشد، وزن زیست توده آن ها افزایش معنی داری به میزان 151 گرم در مترمربع پیدا کرد. در تیمار تداخل تمام فصل بیش ترین وزن خشک کل علف های هرز به دست آمد و تراکم هشت بوته در مترمربع باقلا بالاترین میزان وزن خشک کل علف های هرز را داشت. از نظر عملکرد دانه تیمارهای تداخل تا پنج برگی و تراکم 14 بوته در مترمربع با 27/2010 کیلوگرم در هکتار و تداخل کامل و تراکم هشت بوته در مترمربع با 3/225 کیلوگرم در هکتار به ترتیب بیش ترین و کم ترین عملکرد دانه را داشتند.
    کلیدواژگان: تراکم علف های هرز، ترکیب گونه ای، وزن خشک علف های هرز
  • علیرضا کوچکی، هادی زرقانی، علی نوروزیان صفحات 226-243
    به منظور بررسی و مقایسه ترکیب های مختلف کشت مخلوط سه گونه زراعی آفتابگردان (Helianthus annus L.)، لوبیا قرمز (Phaseolus calcaratus L.) و کنجد (Sesamum indicum L.) بر خصوصیات رشدی، عملکرد و اجزای عملکرد، آزمایشی در مزرعه تحقیقاتی دانشکده کشاورزی دانشگاه فردوسی مشهد در دو سال زراعی 89-1388 و 90-1389 در قالب طرح بلوک های کامل تصادفی با شش تیمار و چهار تکرار انجام شد. ترکیب های مختلف کشت مخلوط شامل مخلوط ردیفی آفتابگردان، کنجد و لوبیا (A)، مخلوط ردیفی آفتابگردان، کنجد و لوبیا قرمز (دو ردیف از هر گونه) (B)، مخلوط نواری آفتابگردان، کنجد و لوبیا قرمز (چهار ردیف از هر گونه) (C) و کشت های خالص آفتابگردان (D)، لوبیا (E) و کنجد (F) (12 ردیف از هر گونه) بود. نتایج نشان داد که اثر ترکیب های مختلف کشت مخلوط بر خصوصیات رویشی، اجزای عملکرد، عملکرد بیولوژیک، عملکرد دانه و شاخص برداشت آفتابگردان، کنجد و لوبیا قرمز معنی دار (01/0p
    کلیدواژگان: کشت مخلوط ردیفی، کشت مخلوط نواری، نسبت برابری زمین
  • عبدالمهدی بخشنده، محمدحسین قرینه، علیرضا ابدالی، محمدرضا مرادی تلاوت، محمد رئیس زاده صفحات 244-254
    به منظور بررسی تاثیر مقادیر مختلف نیتروژن و زئولیت بر خصوصیات کمی و کیفی استویا، آزمایشی به صورت کرت های خرد شده (اسپلیت پلات) بر پایه طرح بلوک های کامل تصادفی در سه تکرار در مزرعه آموزشی- پژوهشی دانشگاه رامین – خوزستان اجرا شد. عوامل مورد بررسی شامل نیتروژن در چهار سطح 50،100،150،200 کیلوگرم در هکتار و زئولیت در سه سطح صفر، سه و شش تن در هکتار بودند. نتایج این تحقیق نشان داد، تحت سطوح کود نیتروژن و تیمارها صفاتی نظیر ارتفاع بوته، تعداد شاخه در بوته، قطر ساقه اصلی و شاخص سطح برگ در سطح یک درصد معنی دار گردیدند. هم چنین برهم کنش تیمارها بر کلروفیل a وb و عدد کلروفیل متر در سطح یک درصد معنی دار گردیدند. عملکرد بیولوژیکی و عملکرد برگ تحت برهم کنش تیمارها در سطح یک درصد معنی دار شدند، که بیش ترین عملکرد بیولوژیک (2253 کیلوگرم برهکتار) و بیش ترین عملکرد برگ (1426 کیلوگرم بر هکتار) در سطوح 200کیلوگرم نیتروژن بر هکتار و شش تن زئولیت بر هکتار به دست آمد. درصد استویوزید برگ نیز تحت سطوح نیتروژن و زئولیت و برهم کنش تیمارها در سطح یک درصد معنی دار شدند، که بیش ترین درصد استویوزید در سطح 150کیلوگرم نیتروژن بر هکتار به همراه سه تن زئولیت بر هکتار (67/10 درصد) به دست آمد.
    کلیدواژگان: استویوزید، عملکرد برگ، عملکرد بیولوژیک
  • ابوطالب منظری توکلی، محمد خواجه حسینی، علی اصغر محمدآبادی صفحات 255-265
    به منظور بررسی تاثیر پیش تیمار بذر و نوع بستر کاشت بر ویژگی های نشاء تولیدی ذرت شیرین آزمایشی به صورت فاکتوریل در قالب طرح کاملا تصادفی با سه تکرار در گلخانه ی تحقیقاتی دانشگاه فردوسی مشهد انجام شد. فاکتورهای آزمایش شامل پیش تیمار بذور در سه سطح: بدون پرایمینگ(p1)، هیدروپرایمینگ (p2) و بیوپرایمینگ (p3) و نوع بستر در هفت سطح: ورمی کمپوست (b1)، پرلیت (b2)، کوکوپیت (b3)، ورمی کمپوست+پرلیت(b4)، ورمی کمپوست+ کوکوپیت(b5)، پرلیت+کوکوپیت (b6) و ورمی کمپوست+کوکوپیت+پرلیت (b7) بودند. نتایج این آزمایش نشان داد که پیش تیمار بذر و نوع بستر بر خصوصیات نشاء ذرت شیرین تاثیر معنی داری داشت. بذور پیش تیمار شده (P2، P3) از لحاظ ویژگی های نشاء نسبت به تیمارهای پپیش تیمار نشده (P1) برتر بودند. تیمار بستر ورمی کمپوست بیش ترین طول اندام هوایی، سطح برگ در بوته، وزن اندام هوایی و وزن ریشه را در بین بسترهای مختلف نشان دادند. بیش ترین سطح برگ در بوته و وزن خشک اندام هوایی به ترتیب با میانگین 111 سانتی متر مربع و 798 میلی گرم در تیمار هیدروپرایمینگ با بستر ورمی کمپوست (P2b1) مشاهده شد. نتایج این تحقیق نشان داد بستر ورمی کمپوست بهترین بستر برای نشاء ذرت شیرین است و هم چنین تیمارهای هیدروپرایمینگ و بیوپرایمینگ نیز باعث بهبود خصوصیات نشاء می شوند.
    کلیدواژگان: خزانه، کود بیولوژیک، گیاه چه، نشاکاری، هیدروپرایمینگ
  • علی ماهرخ، مجید نبی پور، حبیب الله روشنفکر دزفولی، رجب چوکان صفحات 266-278
    کاهش رشد گیاه در شرایط تنش خشکی نتیجه بر هم خوردن تعادل هورمون ها می باشد، بنابراین کاربرد خارجی تنظیم کننده های رشد می تواند عاملی در جهت معکوس کردن تنش های غیر زنده باشد. این مطالعه به منظور ارزیابی کاربرد هورمون های سیتوکینین و اکسین بر عملکرد دانه و اجزای آن در ذرت سینگل کراس 704 در شرایط تنش خشکی اجرا شد. آزمایش در سه محیط جداگانه، شامل محیط بدون تنش خشکی، تنش خشکی در مرحله رشد رویشی و تنش خشکی در مرحله رشد زایشی انجام شد. هورمون های سیتوکینین در سه سطح (شاهد، محلول پاشی در مرحله پنج تا شش برگی و هشت تا ده برگی) و اکسین در سه سطح (شاهد، محلول پاشی در مرحله ظهور ابریشم و 15 روز پس از ظهور ابریشم) در هر محیط در سه تکرار به صورت فاکتوریل در قالب طرح بلوک های کامل تصادفی در مزرعه موسسه تحقیقات اصلاح و تهیه نهال و بذر کرج در سال زراعی 1392 اجرا شد. بیش تر ین عملکرد دانه در محیط بدون تنش و مصرف هورمون اکسین در مرحله ظهور ابریشم به ترتیب با میانگین 80/12 و 24/12 تن در هکتار حاصل شد. اختلاف عملکرد دانه در شرایط تنش زایشی و بدون تنش معنی دار بود و 21/49 درصد نسبت به محیط بدون تنش افت کرد. محلول پاشی هورمون سیتوکینین باعث افزایش تعداد دانه و کاهش وزن دانه شد، ولی محلول پاشی هورمون اکسین باعث افزایش وزن دانه و عملکرد دانه گردید. بر اساس نتایج تجزیه مرکب حاصل از این آزمایش، در شرایط تنش خشکی، محلول پاشی هورمون های سیتوکینین و اکسین به ترتیب در مراحل هشت تا ده برگی و ظهور ابریشم به دلیل برقرای تعادل هورمونی مختل شده، تا حدود 20 درصد مانع از افت عملکرد دانه در شرایط تنش زایشی شدند و به عنوان مراحل حساس در واکنش به این هورمون ها در شرایط تنش خشکی توصیه می شوند.
    کلیدواژگان: تعادل هورمونی، تنش رویشی، تنش زایشی، تنظیم کننده رشد، محلول پاشی هورمون
  • محمود رضا تدین، زینب رئیسی صفحات 279-291
    به منظور بررسی اثر کودهای آلی و شیمیایی بر ویژگی های مورفوفیزیولوژیکی گیاه توتون رقم بارلی، آزمایشی در قالب طرح بلوک های کامل تصادفی با سه تکرار در سال زراعی 92-1391 در مزرعه تحقیقاتی دانشگاه شهرکرد انجام گرفت. تیمارها شامل کود شیمیایی، کمپوست، 50 درصد کمپوست + 50 درصد کود شیمیایی، ورمی کمپوست، 50 درصد ورمی کمپوست + 50 درصد کود شیمیایی و تیمار شاهد بودند. صفات مورد بررسی شامل سطح ویژه برگ، نسبت وزن برگ، ارتفاع بوته، عملکرد لچه برگ ، مجموع عملکرد برگ خشک و محتوای پتاسیم برگ توتون بودند. نتایج نشان داد که بیش ترین مقادیر سطح ویژه برگ و نسبت وزن برگ در کلیه تیمارها در مراحل ابتدایی رشد حاصل شد، و با گذشت زمان مقادیر آن ها کاهش یافت. هم چنین کوددهی، سبب افزایش ارتفاع بوته، عملکرد لچه برگ و مجموع عملکرد برگ خشک توتون گردید. بیش ترین ارتفاع بوته با 162 سانتی متر و عملکرد لچه برگ با 5/216 گرم بر مترمربع از تیمار کود شیمیایی به دست آمد که نسبت به تیمار شاهد، به ترتیب 1/2 و 8/4 برابر افزایش داشتند. بیش ترین عملکرد برگ خشک، به میزان 4/350 گرم بر مترمربع از تیمار کود شیمیایی به دست آمد که تفاوت معنی داری با تیمار کمپوست نداشت اما نسبت به تیمار شاهد به ترتیب 8/2 و 3/2 برابر افزایش داشت. بیش ترین میزان پتاسیم برگ، از تیمار تلفیقی کمپوست به دست آمد که تفاوت معنی داری با تیمار کود شیمیایی نداشت. در مجموع، نتایج نشان دهنده برتری تیمار کود شیمیایی بر عملکرد برگ توتون می باشد که تفاوت معنی داری با تیمار کمپوست نداشت، لذا در راستای تحقق اهداف کشاورزی پایدار و در صورت پذیرش اندکی کاهش در عملکرد برگ، به شرط افزایش کیفیت برگ ها ، استفاده از کمپوست می تواند جایگزین مناسبی برای استفاده از کودهای شیمیایی در مزارع توتون باشد.
    کلیدواژگان: عملکرد برگ، کمپوست، کود شیمیایی، ورمی کمپوست
  • مریم حاجی بابایی، فرهاد عزیزی صفحات 292-303
    به منظور بررسی اثر تنش خشکی بر مراحل رویشی و زایشی بر 14 هیبرید ذرت، آزمایشی به صورت کرت های خردشده در قالب طرح بلوک های کامل تصادفی با سه تکرار در مزرعه پژوهشی موسسه تحقیقات اصلاح و تهیه نهال و بذر کرج طی سال 1388 اجرا گردید. عامل اصلی شامل سه سطح آبیاری نرمال، تنش ملایم و تنش شدید (به ترتیب آبیاری پس از 70، 100 و 130 میلی متر تبخیر تجمعی از تشتک تبخیر کلاسA ) و عامل فرعی نیز شامل 14 هیبرید ذرت شامل 11 هیبرید جدید و سه هیبرید شاهد (KSC704، KSC720، KSC700) بود. در این آزمایش عملکرد دانه در هکتار، عملکرد علوفه خشک در هکتار، تعداد روز تا زمان گرده افشانی، تعداد روز تا ظهور تارهای ابریشمی، فاصله زمانی گرده افشانی تا ظهور کاکل، طول بلال، قطر بلال، تعداد بلال در بوته، تعداد دانه در ردیف و تعداد ردیف دانه در بلال اندازه گیری و محاسبه شد. نتایج نشان داد که تفاوت هیبریدها از نظر تعداد روز تا گرده افشانی، تعداد روز تا ظهور تارهای ابریشمی و فاصله زمانی گرده افشانی تا ظهور کاکل، طول بلال و تعداد ردیف دانه در بلال در سطح احتمال یک درصد و در تعداد ردیف دانه در بلال و عملکرد علوفه خشک در سطح احتمال پنج درصد معنی دار بودند، در حالی که بین هیبریدهای مورد مطالعه اختلاف معنی داری از لحاظ عملکرد دانه، تعداد بلال در بوته و قطر بلال مشاهده نگردید. اثر متقابل هیبرید و رژیم های آبیاری به جز طول بلال برای هیچ یک از صفات دیگر معنی دار نبودند که بیان گر واکنش مشابه هیبریدهای مورد مطالعه نسبت به شرایط رژیم های آبیاری اعم الشده می باشد هم چنین کلیه صفات مورد بررسی به جز تعداد بلال در بوته به تنش خشکی واکنش نشان داده و اختلاف آن ها در سطح احتمال یک درصد معنی دار بود. افزایش دور آبیاری از تیمار آبیاری نرمال به تنش شدید باعث کاهش عملکرد دانه و عملکرد علوفه خشک به میزان 32 درصد و 44 درصد شد. هیبرید شماره 4 (KSC700) با عملکرد دانه (12961 کیلوگرم در هکتار) و عملکرد علوفه خشک (15565 کیلوگرم در هکتار) به عنوان بهترین هیبرید بود که می توان بالا بودن عملکرد در این هیبرید را به طولانی تر بودن دوره رشد آن نسبت داد که زمان بیش تری را برای تولید و تجمع مواد در اختیار گیاه قرار می دهد.
    کلیدواژگان: تعداد روز تا گرده افشانی، رژیم های آبیاری، طول بلال، عملکرد دانه و علوفه
  • سیاوش حشمتی، مجید امینی دهقی، علیرضا رضا زاده، کیوان فتحی امیرخیز صفحات 304-317
    به منظور بررسی اثر کاربرد حاصلخیزکننده های مختلف آلی و شیمیایی فسفر بر میزان رنگدانه های فتوسنتزی رقم گلرنگ بهاره (IL111) در تنش خشکی آزمایشی به صورت اسپلیت- فاکتوریل در قالب طرح بلوک های کامل تصادفی با سه تکرار در مزرعه پژوهشی دانشکده کشاورزی دانشگاه شاهد، در سال زراعی 91-1390 اجرا گردید. عامل اصلی شامل تنش خشکی در سه سطح: آبیاری کامل یا بدون تنش (آبیاری بر اساس تخلیه 50 درصد رطوبت ظرفیت زراعی)، تنش خشکی در مرحله رشد رویشی (آبیاری بر اساس تخلیه 75 درصد رطوبت ظرفیت زراعی) و تنش در مرحله زایشی (آبیاری بر اساس تخلیه 75 درصد رطوبت ظرفیت زراعی) و عامل فرعی به صورت فاکتوریل شامل شش تیمار که سه سطح آن کود شیمیایی فسفر با مقادیر (صفر، 50 و 100 کیلوگرم سوپر فسفات تریپل در هکتار) و کود زیستی فسفر بارور-2، در 2 سطح (تلقیح و بدون تلقیح با بارور2) بود. بررسی صفات مورد مطالعه نشان داد که با اعمال تنش در مرحله رشد رویشی و زایشی، بیش ترین مقدار کلروفیل a، b و کلروفیل کل در تیمار به کارگیری کود زیستی فسفر بارور 2 با مصرف 100 کیلوگرم در هکتار کود شیمیایی فسفر بود. در سطح تنش زایشی، مصرف بالای کود فسفر در تیمار عدم به کارگیری کود زیستی فسفر بارور 2، بیش ترین تاثیر را در افزایش نسبت کلروفیل a به b داشت. اما در تیمار تلقیح کود زیستی، بیش ترین میزان نسبت کلروفیل a به b از کم ترین سطح کودی فسفر به میزان 50کیلوگرم در هکتار فسفر حاصل شد. مقایسه میانگین ها نشان داد که بیش ترین مقدار کاروتنوئیدها، fv/fm، آنتوسیانین، فلاونوئیدها و قندهای محلول در تیمار بدون کود زیستی فسفر بارور 2 از مصرف 50کیلوگرم فسفر در هکتار در شرایط تنش رویشی و زایشی به دست آمد. در سطح تنش در مرحله زایشی، تلقیح کود زیستی همراه با مصرف 50کیلوگرم در هکتار کود فسفر، میزان آنتوسیانین و قندهای محلول برگ را به طور معنی داری افزایش داد. در حالی که مقدار کاروتنوئید و فلاونوئیدها در تیمار به کارگیری کود زیستی بدون استفاده از کود فسفر افزایش داشت. در مجموع نتایج این تحقیق نشان داد که کاربرد کود زیستی به همراه کود فسفر، نقش موثری در افزایش صفات مورد مطالعه گلرنگ در شرایط تنش خشکی داشته است.
    کلیدواژگان: آنتوسیانین، تنش خشکی، کارآیی فتوسیستم 2، کلروفیل، کود زیستی فسفر بارور2
  • احمد رضا بلندی، حسن حمیدی صفحات 318-328
    معرفی ارقام جدید سیب زمینی با عملکرد بالا، زودرس و با کیفیت مطلوب نقش مهمی در امنیت غذایی، کاهش نوسانات قیمت و هزینه های انبارداری و دسترسی به محصول تازه در تمام فصول سال دارد. در این تحقیق، 18 کلون سیب زمینی در ایستگاه تحقیقات کشاورزی جلگه رخ استان خراسان رضوی در قالب طرح بلوک های کامل تصادفی در سه تکرار با سه رقم شاهد اگریا، مارفونا و لیدی رزتا، در سال زراعی 91-1390 از نظر صفات کمی و کیفی مقایسه گردید. نتایج نشان داد که بین ارقام و کلون ها ی مورد مطالعه اختلاف معنی داری از نظر عملکرد کل، عملکرد قابل فروش، درصد ماده خشک، متوسط تعداد و وزن غده در بوته و متوسط وزن تک غده وجود داشت. کلون 16-397007 و رقم مارفونا بیش ترین وزن غده در بوته و کلون9-397097 دارای کم ترین وزن غده در هر بوته بودند. کلون 69 داخلی و 10-397045 به ترتیب بیش ترین و کم ترین تعداد غده در بوته را دارا بودند. در بین کلون ها ی مورد بررسی، بیش ترین درصد ماده خشک مربوط به کلون 69 داخلی بود، که برای تولید چیپس مناسب می باشد. به طور کلی نتایج نشان داد که کلون 16-397007 از نظر وزن غده در بوته و عملکرد کل نسبت به سایر کلون ها برتری داشت.
    کلیدواژگان: تعداد چشم، تعداد غده، درصد ماده خشک، عملکرد قابل فروش، عملکرد کل
  • سمیه حیدری، سید حسن مرعشی، سعید ملک زاده شفارودی، مصطفی قادری زفره ای صفحات 329-342
    کارایی فتوسنتز به میزان زیادی به شرایط محیط زندگی گیاه بستگی دارد. گیاهان در شرایط طبیعی، به سرعت در معرض تغییر شرایط نوری می باشند، برای مقابله با چنین نوساناتی و بهره برداری موثر از انرژی نورانی در دسترس و به طور هم زمان به حداقل رساندن خسارات ناشی از شدت نور بالا به دستگاه فتوسنتزی، مکانیسم های سازگاری در آن ها گسترش یافته است. کاهندگی غیر فتوشیمیایی یک مکانیسم مهم است که انرژی اضافی را به صورت حرارت از گیاه خارج می کند. در این مقاله، مدل ریاضی بسیار ساده ای توسعه داده شده است که توصیف دقیق تری از این فرایند ارائه نموده و قادر به پیش بینی اجزای مختلف و پارامترهای مربوط به آن می باشد. مقایسه نتایج شبیه سازی با داده های تجربی نشان داد که کمپلکس برداشت نوری پروتونه شده و زآزانتین به طور هم زمان در القا و خاموشی فرایند NPQ عمل می کنند. نتایج حاصل می تواند به عنوان پایه تئوری مناسبی برای توسعه مدل های دقیق تر و مطالعه مکانیزم های مولکولی فرایند سازگاری دستگاه فتوسنتز به تغییر شرایط نوری، مورد استفاده قرار گیرد.
    کلیدواژگان: آرابیدوپسیس، فتوسنتز، کاهندگی غیر فتوشیمیایی، مدل سازی
  • عباس رضایی استخروییه، بهاره بابایی صفحات 343-353
    تحقیق حاضر به منظور بررسی اثر سایکوسل بر صفات مورفولوژیک، درصد ازت و پتاسیم گیاه ریحان در شرایط تنش خشکی انجام شد. طرح در سال زراعی 90- 1389 در مزرعه دانشکده کشاورزی دانشگاه شهید باهنرکرمان، به صورت کرت های خرد شده در قالب بلوک های کامل تصادفی با سه تکرار اجرا گردید. کرت اصلی، رژیم آبیاری در سه سطح (100، 75و 50 درصد نیاز آبی گیاه)، کرت فرعی، محلول پاشی با سایکوسل در پنج سطح (صفر (شاهد)، 500، 1000، 1500، 2000 میلی گرم در لیتر) بود. نتایج نشان داد سایکوسل باعث کاهش ارتفاع گیاه شد. کم ترین ارتفاع (با 55/58درصد کاهش نسبت به تیمار شاهد) به تیمار 2000میلی گرم در لیتر سایکوسل تعلق داشت. با افزایش سایکوسل، درصد نیتروژن افزایش یافت. بیش ترین درصد نیتروژن (48/0درصد)، در گیاهان تحت تیمار 50درصد نیاز آبی در 2000میلی گرم در لیتر سایکوسل مشاهده شد. بیش ترین درصد پتاسیم (26/2درصد) مربوط به گیاهان تحت تیمار 100درصد نیاز آبی و 2000میلی گرم در لیتر سایکوسل بود. با زیاد شدن غلظت سایکوسل شاخص سطح برگ گیاه کاهش یافت. کم ترین شاخص سطح برگ مربوط به تنش 50درصد خشکی همراه با غلظت 2000میلی گرم در لیتر سایکوسل بود. در تمام گیاهان تحت تنش، محلول پاشی ، نسبت وزن خشک ریشه به وزن خشک اندام هوایی را افزایش داد. با توجه به نتایج این طرح می توان گفت، استفاده از کند کنند گان رشد به مصرف بهینه آب کمک کرده و می توان در مواجه با بحران کم بود آب در بخش کشاورزی از آن ها کمک گرفت.
    کلیدواژگان: تنش خشکی، ریحان، سایکوسل، صفات مورفولوژیک، مواد معدنی
  • ابراهیم زینلی، افشین سلطانی، محمد خادم پیر صفحات 354-368
    این مطالعه با هدف یافتن روابط آلومتریک بین سطح برگ بوته با تعدادی از صفات رویشی در گیاه ذرت (Zea mays L.) رقم سینگل کراس 704 انجام شد. بدین منظور، در سال 1391 آزمایشی به صورت فاکتوریل در قالب طرح بلوک های کامل تصادفی با سه تکرار در مزرعه تحقیقاتی دانشگاه علوم کشاورزی و منابع طبیعی گرگان اجرا گردید. فاکتورهای آزمایش و سطوح آن ها شامل تراکم بوته (4، 6، 8، 10 و 12 بوته در متر مربع) و تاریخ کاشت (9 خرداد و 9تیر) بودند. نتایج نشان داد که برای توصیف رابطه تعداد برگ در ساقه با واحد دمایی تجمعی، سطح برگ در بوته با وزن خشک برگ در بوته و سطح برگ در بوته با وزن خشک بوته در همه تاریخ های کاشت و تراکم ها می توان از مدل رگرسیون غیرخطی دو تکه ای به ترتیب با ضرایب تبیین 94/0، 98/0 و 95/0 استفاده کرد. هم چنین، یافته های این مطالعه حاکی از آن بود که برای توصیف رابطه سطح برگ در بوته با تعداد برگ (گره) در ساقه در تمام تراکم ها می توان مدل های توانی 36/3y=x (برای تاریخ کاشت 9خرداد) و 286/0y=x (برای تاریخ کاشت 9تیر) با ضریب تبیین 99/0، و برای توصیف رابطه شاخص سطح برگ با ارتفاع بوته در تمام تاریخ های کاشت و تراکم ها مدل توانی 014/0y=x با ضریب تبیین 99/0 را به کار گرفت. با توجه به دقت بالای توابع به دست آمده برای توصیف روابط بین صفات یاد شده با سطح برگ، از این توابع می توان در مدل های شبیه سازی ذرت و هم چنین برای محاسبه سطح برگ استفاده نمود.
    کلیدواژگان: ارتفاع بوته، ذرت، روابط آلومتریک، سطح برگ، وزن خشک برگ
  • ابراهیم ایزدی دربندی، احمد نظامی، روح الله حسن بیگی، مریم جانعلی زاده قزوینی صفحات 369-379
    به منظور بررسی تحمل گیاه دارویی خاکشیر به تنش یخ زدگی آزمایشی در پاییز 1387 به صورت فاکتوریل و در قالب طرح کاملا تصادفی با سه تکرار در دانشکده کشاورزی دانشگاه فردوسی مشهد انجام شد. عوامل آزمایش شامل پنج اکوتیپ خاکشیر ( اقلید، سبزوار، همدان، تربت جام و نیشابور) و 10 دمای یخ زدگی (از صفر تا 18- درجه سیلسیوس با فواصل 2 درجه سیلسیوس) بود. گیاهان تا مرحله پنج-هفت برگی در شرایط آب و هوای طبیعی رشد یافته و با سرما خو گرفتند. سپس برای اعمال دماهای یخ زدگی به فریزر ترموگرادیان منتقل شدند. میزان پایداری غشاء سیتوپلاسمی با استفاده از آزمون نشت الکترولیت ها ارزیابی و سپس دمای کشنده 50 درصد، نمونه ها بر اساس درصد نشت الکترولیت ها (LT50el) تعیین شد. به منظور بررسی میزان هم بستگی بین درصد نشت الکترلیت ها با درصد بقاء، گیاهان باقی مانده به گلخانه منتقل و پس از 21 روز بازیافت، درصد بقاء و سپس دمای کشنده 50 درصد گیاهان بر اساس درصد بقاء (LT50su) محاسبه شد. نتایج نشان داد که بر اساس شاخص های LT50el و LT50su، اکوتیپ های همدان، سبزوار و تربت جام تحمل به یخ زدگی بیش تر ی نسبت به اکوتیپ های نیشابور و اقلید داشتند. بر مبنای شاخص LT50su، اکوتیپ همدان پتانسیل تحمل به یخ زدگی تا دمای 12- درجه سیلسیوس را دارا بود. در این بررسی بین درصد نشت الکترولیت ها و درصد بقاء رابطه منفی و قوی (***72/0-r=) وجود داشت. هم چنین بین LT50el و LT50su هم بستگی مثبت و بالایی (*53/0r=) دیده شد.
    کلیدواژگان: اکوتیپ، بازیافت، درصد بقاء، دمای 50درصد کشندگی
  • قدریه محمودی، علی قنبری، مهدی راستگو، مصطفی قلی زاده، ایرج طهماسبی صفحات 380-391
    به منظور بررسی اثر میدان مغناطیسی بر روی نحوه رشد و تولید ماده خشک کل در نخود، آزمایشی به صورت کرت های نواری با سه تکرار در مزرعه تحقیقاتی دانشکده کشاورزی دانشگاه فردوسی مشهد در سال 1392 اجرا شد. تیمارهای آزمایش شامل: 1- بذر در سه سطح (عادی، تیمار شده در میدان مغناطیس با شدت های 100 و 150میلی تسلا هر یک به مدت 2 ساعت)، 2- آب آبیاری در 2 سطح (عادی و تیمار شده در میدان مغناطیسی با شدت 650 میلی تسلا) بود. نتایج این آزمایش نشان داد که قرار دادن بذر در میدان مغناطیسی موجب افزایش معنی دار ماده خشک به میزان 26 درصد نسبت به بذور عادی شد. شدت میدان مغناطیسی نیز تاثیر معنی داری بر ماده خشک تولیدی داشت و میدان 150 میلی تسلا نسبت به میدان 100 میلی تسلا موجب افزایش 18 درصدی (01/0 P≤) ماده خشک شد. آب مغناطیسی، حدود 25 درصد نسبت به آب معمولی میزان ماده خشک تولیدی نخود را افزایش داد. اختلاف تیمارها با هم در اواخر فصل رشد و در 80 روز و 96 روز بعد از کاشت بیش تر ین مقدار (به ترتیب 201 و 207 گرم بر متر مربع ) بود. هم چنین اعمال میدان مغناطیسی بر روی آب آبیاری و بذر نخود به ترتیب منجر به افزایش 27 و 19 درصد عملکرد دانه شد. اثرات متقابل تیمارها نشان داد که اعمال میدان مغناطیس در آب آبیاری و بذر نخود سبب افزایش 31 درصد عملکرد دانه شد. اما بر روی تولید ماده خشک نخود تاثیر مثبت نداشت.
    کلیدواژگان: آبیاری مغناطیسی، عملکرد دانه، معادله سیگموئیدی
  • امیرهوشنگ جلالی صفحات 392-402
    شرایط انبارداری بر ویژگی های زراعی سیب زمینی در شرایط مزرعه تاثیر گذار است. تاثیر یک دوره سه ماهه انبارداری، شامل دو تیمار 440 درجه روز رشد (تیمارهای T1 و T2 با دمای میان دوره متفاوت)، دو تیمار 880 درجه روز رشد (تیمارهای T3 و T4با دمای میان دوره متفاوت)، یک تیمار 80 درجه روز رشد (T5) و یک تیمار شاهد (T6 بدون دریافت درجه روز رشد) بر ویژگی های زراعی و عملکرد دو رقم سیب زمینی راموس و مارفونا با استفاده از آزمایش فاکتوریل بر پایه طرح بلوک های کامل تصادفی با چهارتکرار در مرکز تحقیقات کشاورزی کبوتر آباد اصفهان بررسی شد. نتایج این پژوهش نشان داد تاثیر دما و برهم کنش تیمارهای دمایی و رقم، بر عملکرد و اجزای عملکرد سیب زمینی معنی دار بود. رقم مارفونا و استفاده از تیمار T3 با 51733کیلوگرم در هکتار غده، بالاترین مقدار عملکرد را تولید کرد، اما بین عملکرد این تیمار و تیمار دمایی T2 و هم چنین عملکرد رقم راموس و تیمارهای T3 و T4 تفاوت معنی دار وجود نداشت. برای هر دو رقم استفاده شده، تیمار T3 حداکثر تعداد ساقه در بوته را تولید نمود. شاخص برداشت در تیمارهای دمایی مختلف در رقم راموس از 5/63 تا 1/76 درصد و در رقم مارفونا از 64 تا 6/79 درصد در نوسان بود. نتایج این پژوهش نشان داد، با مدیریت دمای انبار می توان عملکرد محصول سیب زمینی را به ویژه در مناطقی با طول دوره رشد کوتاه افزایش داد.
    کلیدواژگان: درجه روز رشد (GDD)، سن فیزیولوژیک، شاخص سطح برگ (LAI)
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  • M. Dabaghzadeh, Gh Fathi, A. Bakhshandeh, Kh Almi, Said Pages 215-225
    Introduction
    Broad bean (Vicia faba L.) belongs to the Fabaceae family and is the most important protein plant in the world. Although broad bean used as cover crop is able to deal with weeds, but the evidence show that yield of the plant decreased 32-82% because of competition with weeds. Using crop density is one of the ecological approaches in weed management. Broad bean density can produce biomass, weed competition, seed yield and ultimately influence the economic yield. Many reports show that increasing crop density reduced negative effects of weeds. The aim of this experiment was to evaluate the effect of weeds interference and different densities of broad bean on density and biomass of weeds and broad bean seed yield.
    Materials And Methods
    The experiment was carried out as split plot in randomized complete block, with four replications, during 2009-2010 in a field experiment at Ramin Agricultural and Natural Resources University, Ahwaz. Weeds interference was investigated on 5 levels, including V5, V9, V13 broad-bean phonological stages, full season weeding and full season weeds interference selected as main plots, and broad-bean density on 3 levels: including 8, 11 and 14 plants m-2 as subplots. Density, dry weight and diversity of weeds and seed yield of broad bean were evaluated.
    Results And Discussion
    The results showed that the weeds including wild beet, field bindweed and mallow had the highest occurrence (26.35, 21.17 and 18.46 plants m-2 respectively) in V9 broad-bean phonological stage, where the peak abundance of weeds was observed. The frequency of mallow, clover and yellow alfalfa were high until V5 broad-bean phonological stage, but in the next stages, they were replaced by other weeds and sorrel. It was also observed that the environmental factors can affect composition of weeds, for example, as the temperature increased in the early spring, an increase in the density of field bindweed was recorded. In the treatment of 8 plants m-2 of broad-beans, the highest frequency was recorded for mallow, clover and wild beet (15.2, 14.18 and 13.68 plants m-2). With the increased interference time period, from V9 broad-bean phenological stage on, the weed density was reduced due to "within species"(intra_species) competition of weeds and "between species" (inter_species) competition of weeds and the crop. As the time period of weeds interference increased, the dry weight reached its highest level, so that in full season weeding treatment, it reached 172.99 g m-2. Increasing the density of broad-bean from 8 to -14 plants m-2, decreased the weeds total dry weight from 92.42 to 83.76 g m-2 .Also increasing the weeds interference duration, reduced the seed yield, so that the highest yield, with the average of 2473.5 kg ha-1, was obtained in full season weeding treatments. Among the treatments of broad-bean density, the highest seed yield of 1342 kg ha-1 in average, was obtained from density treatment of 14 plants m-2. Among the treatments of interaction, weeds interference and Broad-bean density, Broad-bean density had a significant effect on the seed yield. The highest seed yield was observed in full season weeding treatment and the density of 14 plants m-2, with an average of 2699.87 kg ha-1, and the lowest seed yield was recorede in the treatment of full season interference and density of 14 plants m-2 with an average of 228.309 kg ha-1.
    Considering the results of this study, where weeding is not to be applied in V13 broad -bean phenological stage and next stages, the minimum density (8 plants m-2) is recommended, because density had no significant effect on broad-bean yield, this would reduce the cost of production.
    Conclusions
    It can be concluded that increasing the duration of weeds interference, reduced the seed yield and weeds density while it increased the weeds dry weight. Increased broad-bean density, also, reduced the density and dry weight of all the weeds. The best time to control weeds for optimum performance of broad-bean, was prior toV13 broad-bean phenological stage.
    Keywords: Species diversity, Weeds density, Weeds dry weight
  • A. Koocheki, H. Zarghani, A. Norooziyan Pages 226-243
    Introduction
    Intercropping is a sustainable practice used in many developed and developing countries and an essential element of agricultural sustainability. Intercropping is simultaneous growing of two or more crops during a given season on same location. Such a method enables the utilization of common limiting resources more efficiently than the species grown separately. Using two species with different growth habits and the least competitive characteristics in intercropping, increases the efficiency of resources (light, water and nutrients) and absorption in comparison with the sole cropping (Fernandez-Aparicio et al., 2008). The study of intercropping of borage (Borago officinalis L.) and bean (Phaseolus vulgaris L.) showed that the highest economic yield was achieved in monoculture and the lowest economic yield was obtained in four rows of borage plus four rows of bean, but the maximum land equivalent ratio was calculated in 2:2 intercropping. The aim of current study was to determine the best combination and efficiency of resource utilization in intercropping of additive series of chickpea and black cumin. The results were compared to respective monoculture and the advantages of intercropping was determined. The effects of planting different ratios of two crops on yield and yield components of sesame (Sesamum indicum L.) and chickpea (Cicer arietinum L.) was also investigated. The results of intercropping of additive series showed that the highest grain and biological yield of chickpea were obtained through monoculture and the lowest grain and biological yield of chickpea achieved by planting ratio of 100% sesame and 10% chickpea.
    Materials And Methods
    To evaluate the effects of different intercropping arrangements of sunflower, sesame and red bean on growth characteristics, yield components and yield, a field experiment was conducted at Agricultural Research Station of Ferdowsi University of Mashhad, Iran during two growing seasons of 2009-2010 and 2010-2011. For this purpose a randomized complete block design with six treatments and four replications was used. Treatments were: (A) one row for each special intercropping, (B) row intercropping (two rows for each species), (C) strip intercropping (four rows for each species) and (D) sole crop of sunflower, (E) sole crop of red bean and (F) sole crop of sesame (twelve rows for each species).
    Land equivalent ratio (LER)
    Land equivalent ratio of sunflower, sesame and red bean was calculated (Sullivan, 2003) as:LER= Y1/L1捯
    Where Y1 and Y2 represent sunflower, sesame and red bean yield in intercropping and L1 and I2 represent sunflower, sesame and red bean yield in mono-culture, respectively.
    Statistical analyses: SAS ver. 9.1 and MSTAT-C softwares were used for statistical analysis. To compare the means, Duncan's multiple range test at 5% probability level was used.
    Results And Discussion
    Results showed that the growth characteristics, yield and yield components of sunflower, sesame and red bean were significantly (p≤0.01) affected by different intercropping arrangements. There was a decreasing trend in these parameters from intercropped towards the sole crop for sesame and red bean and an increasing trend for sunflower. The highest biological and economic yield of sesame (4751 and 2207 kg ha-1, respectively) and red bean (5701 and 2719 kg ha-1, respectively) were observed in monoculture. There was a decreasing trend in land equivalent ratio (LER) from row intercropped toward, strip cropping. Maximum and minimum LER were observed in A and C with 1.38 and 1.02, respectively.
    Conclusions
    According to the results, intercropping of sunflower, sesame and red bean can be beneficial in terms of ecological management. In general the arrangements of sunflower, sesame and red bean could be recommended for achieving high yield in sunflower in this region.
    Keywords: LER, Row intercropping, Strip intercropping
  • A. Bakgshandeh, M. H. Gharineh, A. R. Abdale, M. R. Moraditelavat, M. Reiszadeh Pages 244-254
    Introduction
    Nowadays due to population growth and higher levels of welfare, one of the main social problems is providing appropriate food resources. In this regard, finding the alternative food resources, improvement of existing technologies and providing new technologies seem inevitable. Although sugar is a very important substance and has special place in household’s basket and economy, the harmful effects of excessive consumption of sugar should not be neglected. Stevia is a plant with a widespread root system which has a couple of years lifetime. The stems of Stevia are brittle and small and produce elliptical leaves. At first the leaves will be dried and then they will be powdered or wetted in the water and will be used for sweetening of beverages, sweet drinks, chewing gums, chocolates, cakes, etc. Stevia is one of 950 genera belonging to the family of Asteraceae plant. Stevia leaves are used for sweetening foods. Sweetness of Stevia comes from the d. terpenoides glycosides that exist in different parts of the plant. Glycosides are the result of secondary metabolism in the plants. In different components of the Stevia body, there are about 10 major glycoside compositions which the steviozede and Rbadiozide glycosides have more importance in sweetening property of Stevia compared to other sweet glycosides. Nitrogen is considered as one of the key elements in the nutrition of crops and the most important element in limiting the plant growth. Due to increased cation exchange capacity and a high tendency to absorb and retain ammonium, use of clinoptilolite on agricultural lands can have an effective role in reduction of nutrient washing especially nitrogen from soil.
    Materials And Methods
    In order to investigate the effect of different levels of nitrogen and natural zeolite on qualitative and quantitative yield of Stevia in Ahvaz climate, a trial agricultural research field was selected at the farm of agricultural and natural resources of Ramin Khuzestan in 2012-2013. A split plot experiment in a randomized complete block design with 3 replications was conducted. The levels of nitrogen fertilizer (50, 100, 150 and 200 N kg /ha) were applied in the main plots and based on similar studies, the levels of zeolite (including zero, 3 and 6 tons per hectare) were applied in subsidiary plots. Transplants were cultured in 2013/3/6. Harvest was done after growth and development of plant in 2013/6/10. In order to determine the performance of harvested plants from each plot, after packaging and label-making, the samples were weighted in order to estimate the wet weight. The samples were dried in an oven at 72 °C for 48 hours and reweighted again, and then the dried matter performance was determined. To measure the percentage of steviozide, leaf samples were collected from each plot and dried in an oven at 70 °C for 48 hours, then they were milled, powdered and half a gram of Stevia leaves powder in 50 ml of 70% ethanol was obtained from each sample plot. The Stevia leaf steviozide percentage was measured using a HPLC device. Before the analysis the device was calibrated.
    Results And Discussion
    Results showed that the highest biological performance (2253 kg ha-1), the highest leaf performance (1426 kg ha-1), the maximum stem diameter (1.66 cm), the maximum height (69 cm) and the maximum leaf area index (4.88) were obtained at the treatment of 200 kg nitrogen per hectare and the largest number of branches per plant was obtained in the 150 N kg /ha-1 treated with the use of 6 tons zeolite. Maximum percentage of steviozede (10.67) was related to 150 kg pure nitrogen per hectare with 3 tons of zeolite. LAI as a minor component of plant growth was affected directly by nitrogen fertilizer, by increasing the fertilizer, growth and leaf area of plant per square meter will be added. Leaves of the plant that consist the most part of the plant, were influenced by nitrogen fertilizer, with increasing nitrogen, growth and performance of leaves were also increased. The zeolites reduced the amount of nitrogen leaching in the soil due to frequent watering that plant needs. As a result, the plant uses nitrogen and other elements that all are useful in the vegetative growth, effectively. According to the results, interaction effect of nitrogen fertilizer and zeolite levels on the SPAD reading was significant at one percent level. The presence of nitrogen in chlorophyll causes the significant effect of increasing nitrogen fertilizer on chlorophyll content of leaves. Existence of chlorophyll as a light absorbent and synthesis of materials is vital for plant growth. The use of zeolites increases the soil cation exchange capacity and consequently the efficiency of nitrogen fertilizer in the soil. So the plant can use fertilizers better and subsequently vegetative growth increases. According to the results, there is a close relationship between supplying food components and accumulation of glycosides steviol in Stevia.
    Conclusions
    Stevia is a plant with few years life with several times harvesting each year. This plant was cultivated in 2013/3/6 and harvested in 2013/6/10. Results showed although Stevia was planted for the first time in the study area it had consistency with the regional climate. Use of nitrogen fertilizer and zeolite had a significant effect on chlorophyll components and biological performance of leaves and also on morphological characteristics of plant and nitrogen fertilizer. The zeolites increased cation exchange capacity of the soil which enhanced the efficiency of nitrogen fertilizer in the soil and resulting in the better usage of fertilizers by the plants and increasing the vegetative growth (biological and leaf yield) and percentage of steviozede.
    Keywords: Biological performance, Leaf yield, Steviozede
  • A. Manzari, Tavakkoli, M. Khajeh, Hosseini, A. A. Mohammad Abadi Pages 255-265
    Introduction
    Corn (Zea mays L.) is one of the main cereals in the tropical and temperate regions of the world. Sweet corn obtained from a genetic mutation on chromosome 4 locus SU conventional maize resulting accumulation of sugars and polysaccharides which are soluble in seed endosperm. Unlike other types of corn, sweet corn endosperm contains a lot of sugar to starch, which is called Amylodextrin and it is soluble in water. Producing healthy and uniform plants is one of the requirements of modern agriculture. Considering the unsuitable climatic condition in Iran (arid and semiarid) transplantation is one of the requirements for sustainable agriculture particularly in sweet corn production with high water requirement where transplantation is able to save at least 2-3 times of irrigations. Therefore, producing high quality transplants is an important practice for successful seedling establishment. Hence, the objective of this study was to evaluate the effects of seed priming and substrate types on the characteristics of sweet corn transplants.
    Materials And Methods
    This experiment was conducted as factorial based on a completely randomized design with three replications. Treatments were three levels of seeds pretreatment: no priming (p1), hydropriming (p2) and biopriming (p3), and another factor was seedbeds types in seven levels including: vermicompost (b1), perlite (b2), cocopeat(b3), vermicompostꗪ(b4), vermicompost cocopeat (b5), perlite cocopeat (b6) and vermicompost cocopeat ꗪ (b7). Biopriming using bioaminopalis biological fertilizer applied on the seeds for 24hours in a solution containing micro-organisms such azotobacter and Pseudomonas. Then the non-primed and the primed seeds were sown in the plastic pots and grown in a greenhouse with average temperature of 22-25° C. Samples were taken three weeks after planting.
    Results And Discussion
    Mean emergence time
    Emergence is shoot elongation and growth leading the shoots out of the soil. Shorter mean emergence time indicates the plants emergence more quickly as a desirable characteristic. Results from analysis of variance showed that the mean emergence time was significantly influenced by seed priming treatments (P≤0.01). The type of seedbed and interaction of two factors, seedbed and priming had no significant effect on mean emergence time (Table 1). Non treated seeds (P1) had the longest mean emergence time of 3.06 days compared with treated seeds (P2, P3) (Table 2).
    Shoot length
    The results showed that the type of the seedbed and seed priming pretreatment had a significant effect on the shoot length on the sweet corn transplants. The interaction between these two factors on shoot length was also significant (Table 1). Bioprimed seeds produced transplants with 17.86 cm shoot length superior to the non-primed seeds, while it did not show statistically significant difference with the hydroprimed seeds. Sweet corn seeds inoculation with bacteria resulted a significant increase in the seedling shoot length. Sayed-Sharifi and Khavazi (2011) also found similar results. Seed bed also had a significant effect on sweet corn seedling shoot length. As the vermicompost cocopeat and vermicompost seedbeds produced seedlings with shoot length of 21 and 20.68 cm respectively, while perlite犇 peat and perlite showed the lowest shoot length of 10.98 and 11.08 respectively (table 2). Nicknam et al. (2012) also investigated the influence of different substrates on the growth of two cultivars of lily (Lilium ledebourii) and found that seedbeds containing vremikvlayt and perlite produced transplants with a shorter shoot length. P3b5 treatment where the seeds primed with microorganisms such as pseudomonas and the seedlings grown in the vermicompost resulted in the highest (24 cm) shoot length possibly due to more availability of the nutrients while P1b2 treatments produced the shortest (9.9 cm) shoot length seedlings (Figure 1)
    Leaf area
    The seeds pretreatment (P≤0.05), the kind of seedbed and the interactions between these factors (P≤0.01) have significant effect on the sweet corn leaf area (Table 1). The seedlings of the bioprimed seeds produced a higher leaf area of 60.65 cm2 compared with the control and hydropriming treatments possibly due to more availability of the nutrients. Seed pretreatment with biological fertilizer of bioaminopalis that contained bacteria, azotobacter and pseudomonas had direct and indirect effects on plant growth leading to expansion of the leaf area. The direct effects of these bacteria could be used in producing chemical components needed for plant growth, facilitating nutrients uptake, atmospheric nitrogen fixation and plant hormones production such as auxin and gibberellins, enhancing plant growth in various stages of development, or construction of enzymes involved in the plant growth.
    Conclusions
    Seed priming and vermicompost seedbed improved the quality of the produced transplants. This system was recommended for sweet corn production in Iran using transplants in order to save at least 2-3 times of the irrigation per year where the country is suffering from serious water crises.
    Keywords: Biological biofertilizer, Hydropriming, Nursery, Seedling, Transplanting
  • A. Mahrokh, M. Nabi Pour, H. A. Roshanfekr Dezfuli, R. Choukan Pages 266-278
    Introduction
    Drought is one of the major environmental conditions that adversely affects plant growth and crop yield. In the face of a global scarcity of water resources, water stress has already become a primary factor in limiting crop production worldwide. Drought is the major restriction in maize production. The plant growth reduction under drought stress conditions could be an outcome of altered hormonal balance and hence the exogenous application of growth regulators under stress conditions could be the possible means for reversing the effects of abiotic stress. Phytohormones such as auxine and cytokinine are known to be involved in the regulation of plant response to the adverse effects of stress conditions. Previous studies have shown that endogenous hormones are essential regulators for translocation and partitioning of photoassimilates for grain filling in cereal crops, and therefore could be involved in the regulation of grain weight and yield.
    Materials And Methods
    The experiment was carried out in three separately environments included non-drought stress environment (irrigation after soil moisture reached to 75% field capacity), drought stress in vegetative stage (irrigation after soil moisture reached to 50% field capacity in V4 to tasseling stage, but irrigation after soil moisture reached to 75% field capacity in pollination to physiological maturity stage) and drought stress in reproductive stage (irrigation after soil moisture reached to 75% field capacity in V4 to tasseling stage and irrigation after soil moisture reached to 50% field capacity in pollination to physiological maturity stage). Cytokinin hormone in three levels (control, spraying in V5 –V6 and V8-V10 stages) and auxin hormone in three levels (control, spraying in silk emergence stage and 15 days after that) were laid out as a factorial design based on randomized complete block with three replications in each environment at Seed and Plant Improvement Institute (SPII), Karaj, Iran, in 2013. Indole-3-butyric acid and N6-benzyladenin were used as auxin and cytokinin hormones, respectively. Concentration of auxine and cytokinine hormones were 10 and 50 mg per liter, respectively. Harvesting was done from 4.5 m2 at field maturity stage with 14 % grain moisture for estimating grain yield and yield components. SAS software (version 9.1) was used for statistical analysis. Traits means were compared by Duncan's multiple range tests in 5% probably level.
    Results And Discussion
    Drought stress effect was significant (P≤0.01) for ear number per plant, row/ear, grain number per m2, 1000 kernels weight and grain yield and it wasn’t significant for kernels/row. Spraying cytokinine hormone was significant (P≤0.01) on ear number per plant, row/ear, grain number per m2 and it was also (P≤0.05) significant for 1000 kernels weight but it wasn’t significant for kernels/row and grain yield. Spraying auxine hormone was significant (P≤0.01) for1000 kernels weight and grain yield and it wasn’t significant forother yield components. The maximum yield was obtained 12.80 and 12.24 tons per hectare in non-stress environment and using auxin hormone in silk emergence stage, respectively. Grain yield was decreased 49.21% under reproductive drought stress and grain yield difference between non drought stress and vegetative drought stress was not significant. Spraying cytokinine hormone increased ear number by 10% in V8-V10 stage. The maximum row/ear was 16.16 kernels per row which was obtained by spraying cytokinine hormone in V8-V10 stage. Spraying cytokinine hormone increased grain number per m2 up to 20.75% in V8-V10 stage but it decreased 1000 kernels weight up to 13.76% in the same stage. The maximum 1000 kernels weight was 313.87 gr that was obtained by spraying auxine hormone in silk emergence stage. Spraying auxine hormone increased grain yield up to 23.38% in silk emergence stage.
    Conclusions
    Based on the results of this experiment, maize was tolerant to drought stress up to 50% field capacity in vegetative stage, but grain yield was decreased by 48.04% under drought stress condition in reproductive stage, and spraying cytokinine and auxine hormones in V8-V10 and silk emergence stages respectively, could prevent about 20% of decreasing of grain yield. Therefore, under drought stress condition, spraying cytokinine and auxin hormones in V8 –V10 and silk emergence stage can be recommended as the best time for using these hormones respectively, because they can balance hormones rate disturbs under drought stress condition.
    Keywords: Drought in reproductive stage, Drought in vegetative stage, Growth regulative, Hormonal balance, Spraying hormone
  • M. R. Tadayon, Z. Reisi Pages 279-291
    Introduction
    Tobacco with scientific name of (Nicotiana tabacum L.) belongs to Solanaceae family is one of the important industrial crops in the world that plays a critical role in economy of producing countries and its income from various products had a major share of the national income. Tobacco is an annual, short day length and self pollinated crop that its chromosomal number is 2n=48. The yield of plants depends upon several production factors. Among these proper, balanced nutrition plays a significant role. The main purpose of fertilization in tobacco plants not only the quantity but quality should be considered. Now tobacco farmers apply a large amount of fertilizer to improve yields, but these actions not only decrease tobacco leaf quality, but also cause fertilizer pollution. Organic and chemical fertilizers use has played a significant role in increase of crop yield. The use of compost and vermicompost in the soil, generally in order to maintain and increase aggregate stability and fertility of soils for farming and gardening in the past decade has been of particular importance. Increasing soil organic matter stocks and stability by addition of organic amendment offers a good way to substantially improve soil quality and therefore agricultural sustainability. The objective of this study was evaluate the effect of chemical and organic fertilizer on morpho-physiological and yield of tobacco in field conditions.
    Materials And Methods
    In order to study the effects of organic and chemical fertilizers on morpho-physiological traits of baurley tobacco cultivar, an experiment was counducted as based on a randomized complete block design with three replications during growing season of 2012-2013 at the research field of Shahrekord University located in 50º 49´ E longitude and 32º21´ N latitude.with sea level of 2116 meter. Treatments included chemical fertilizers based on the tobacco needs and soil test results, compost based on the tobacco needs and soil test results, 50 percent compost 50 percent chemical fertilizer, vermicompost based on the tobacco needs and soil test results, 50 percent vermicompost 50 percent chemical fertilizer and control (no use of fertilizer). Sowing in nursery was done in March 2013 and transplanted to field May 2013. After plowing and disking and leveling by rotary, tobacco seedling were transplanted in main field. In current study the space between rows was 80 cm and between plants on rows was 50 cm. Number row planting in each plots were 6 rows. The area of every plot was 5×4 m2. Traits of specific leaf area, leaf weight ratio, plant height, tips yield, total dry leaf yield and potassium content on leaf of tobacco were evaluated. The data were analyzed by using version 9.1 SAS. Least Significant Difference test was used to compare the means at 1% of significant. Also, the figures were draw by Excel 2010 software.
    Results And Discussion
    The results showed the highest specific leaf area and leaf weight ratio in all treatments achieved in the early stages of plant growth, and after that, this values decreased. Maximum specific leaf area and leaf weight ratio in the lastly stages of plant growth, respectively, were obtained from 50 percent compost 50 percent chemical fertilizer treatment and vermicompost treatment. Minimum specific leaf area in the lastly stages of plant growth was obtained from chemical fertilizer and vermicompost treatments. Minimum leaf weight ratio was obtained from chemical fertilizer treatment. Fertilization increased the plant height, tips yield, total dry leaf yield and potassium content on leaf of tobacco. The highest plant height with 162 cm and the tips yield with 216.5 g m-2 were obtained from chemical fertilizer treatment, wich were 2.1 and 4.8 times higher compared to control, respectivly. The highest total dry leaf yield with 350.4 g m-2 obtained from chemical fertilizer treatment and had not difference with compost treatment but showed significant increase with 2.8 and 2.3 times more with control. After that the highest total dry leaf yield, related to vermicompost, 50 percent compost 50 percent chemical fertilizer and 50 percent vermicompost 50 percent chemical fertilizer treatments. Minimum total dry leaf yield with 126.2 g m-2 was obtained from control treatment. Maximum potassium content on leaf was obtained from 50 percent compost 50 percent chemical fertilizer treatment and also chemical fertilizer treatment and control treatment with 2.34 percent had the lowest potassium content on leaf.
    Conclusions
    Therefore, in order to fulfill the objectives of sustainable agriculture and the adoption of a slight decrease in leaf yield, on condition of increasing the quality of the leaves, compost can be a good alternative to the use of chemical fertilizers in the tobacco fields.
    Keywords: Chemical Fertilizer, Compost, Leaves Yield, Vermicompost
  • M. Hajibabaei, F. Azizi Pages 292-303
    Introduction
    Maize is one of the most important cereals which its global production is severely affected by drought in many parts of the world. One of the best ways of water management on field is to choose the proper variety which could be chosen indirectly by the traits affecting the grain yield.
    Materials And Methods
    In order to study the effect of drought stress in vegetative and reproductive stages in 14 corn hybrids, an experiment was conducted at the experimental field of Seed and Plant Improvement Institute of Karaj, in 2009. The Research Station located in 50°, 55´ eastern latitude and 35°, 47´ northern longitude with 1254 height above mean sea level (AMSL). The soil texture of the location was loam-clay with pH= 7.5 and the Electrical Capacity (EC) = 0.7 dsm-1. The experiment was carried out using split-plot in a randomized complete block design (RCBD) with three replications. The main plots consisted of three levels of irrigation regimes (irrigation after 70, 100 and 130 mm cumulative evaporation from evaporation pan class A) and sub-plots included 14 new corn hybrids Includes eleven new hybrids such as (K47/2-2-1-4-1-1-1×MO17¡ K3653/2×K19¡ KLM76004/3-2-1-1-1-1-1-1×K3545/6¡ K3653/2×MO17¡ K74/2-2-1-2-1-1-1-1×K3545/6¡ K47/3-1-2-7-1-1-1×MO17¡ K47/2-2-1-2-2-1-1-1×K3544/1¡ KLM76004/3-2-1-1-1-1-1-1×K3544/1¡ K47/2-2-1-2-1-1-1-1×K3544/1¡ KLM77029/8-1-2-3-2-3×MO17 and KLM76005/2-3-1-1-1-1×MO17) and three hybrid control (KSC704, KSC720, KSC700). Irrigation time was determined using daily evaporation rate of standard class A evaporation pan. To determine the volume of water per irrigation, a sample of each plot from depth of root development was prepared before irrigation. The samples were kept in oven 80°C for 24 hours. The weight of soil moisture content was calculated and the volume of water per irrigation was calculated using equations 1 and 2.
    1: H = ρb (F.C - m) D
    2: V = H × A
    Where H is the water height in the plot, ρb is soil bulk density, F.C is the moisture level at field capacity, m is plot moisture mass desired at irrigation time, D is the root development depth, V is the volume of irrigation water in the plot, and A is the plot area. From each plot 10 plants were randomly selected to determine traits such as dry forage yield per hectare. In this experiment kernel yield per hectare, Dry forage yield per ha, Number of days until to pollination, number of days until silk emergence cords and period of pollination until silk emergence, ear length, ear diameter, number of ear in corn, number of kernels per row and number of rows per ear measured and calculated.
    Results And Discussion
    The results showed that hybrid differences in terms of number of days until the pollination, number of days until silk emergence cords, period of pollination until silk emergence and ear length was significant at 1% probability level. No significance differences were observed between hybrids for kernel yield, total number of kernels per ear, number of ear in corn and ear diameter. Hybrid and irrigation regimes interactions were not significant for any of the traits except for ear length that represent the same reaction of hybrids to the irrigation regimes. Evaluation of dry forage showed significant difference between years (P
    Keywords: Ear Length, Forage, Kernel Yield, Irrigation Regimes, Number of Days Until to Pollination
  • S. Heshmati, M. Amini Dehaghi, A. Rezazadeh, K. Fathi Amirkhiz Pages 304-317
    Introduction
    Drought stress is one of the most important and effective factors in agricultural practices in arid and semi-arid regions of the world. The arid and semi-arid regions comprise more than 70% of the total area of Iran. Reduction in chlorophyll concentrations has been attributed to the increase in chlorophyll degradation in water deficit conditions and impairment in the enzymes activity responsible for the synthesis of photosynthetic pigments. Under drought stress, maintenance of photosynthetic capacities and leaf chlorophyll are physiological parameters which influence drought stress tolerant of crop. Phosphorus is one the most essential elements for plant growth after nitrogen. However, the availability of this nutrient for plants is limited by different chemical reactions especially in arid and semi-arid soils. Plant growth-promoting bacteria (PGPB) are soil and rhizosphere bacteria that can benefit plant growth by different mechanisms. Given the negative environmental impact of chemical fertilizers and their increasing costs, the use of PGPB as natural fertilizers is advantageous for the development of sustainable agriculture. Inoculation of plants with native beneficial microorganisms may increase drought tolerance of plants growing in arid or semi-arid areas.
    Materials And Methods
    In order to study the effect of biologic and chemical phosphorous fertilizer on photosynthetic pigments of safflower cultivar (IL111), under water deficit condition, an experiment was conducted in 2012 at the Research Field of the Faculty of Agriculture, Shahed University. The experimental design was split-factorial arrangement in randomized complete block design with three replicates. The main factors were the three levels of irrigation treatment: full irrigation (irrigation up to 50% soil moisture depletion relative to field capacity), water stress in the vegetative and flowering stages (irrigation up to 75% soil moisture depletion relative to field capacity). The sub-factors were the six treatments resulting from three levels of phosphate chemical fertilizer (0, 50, and 100 kg ha-1 Triple Super Phosphate), each at two levels of Barvar-2 bio-fertilizer (with and without inoculation with Barvar-2). The applied biological fertilizer was in the type of the bacteria which release the phosphorus from soil components and neutralize the soil pH. The commercial name of the biologic fertilizer is Barvar-2. The effective gradients of the biological phosphorus fertilizer is comprised of two bacteria strains of p5 (Bacillus lentus) and p13 (Pseudomonas potida) with 108 cfu (colony forming units) which have been screened from soil bacteria populations. The bacteria strain p5 (Bacillus lentus) dissolves P from soil mineral compounds while p13 (Pseudomonas potida) separates P from soil organic compounds by exerting a variety of phosphatase enzymes.
    Results And Discussion
    The results showed that the highest amount of chlorophyll a, b and total chlorophyll obtained with application of chemical phosphorus by 100 kg ha-1 Triple Super Phosphate followed by inoculation with Barvar-2 under water deficit condition at vegetation and flowering stages. At drought stress in flowering stage, use of high level of phosphorus without inoculation with Barvar-2, had highest effect in terms of increasing amount of chlorophyll a/b ratio, but at treatment of inoculation with Barvar-2, the highest amount of chlorophyll a/ b ratio obtained with low level of chemical phosphorus by 50 kg ha-1 Triple Super Phosphate. The means comparison showed that highest amount of carotenoids, fv/fm, anthocyanin, flavonoids and soluble sugars obtained with application of chemical phosphorus by 50 kg ha-1 Triple Super Phosphate without Barvar-2 under water stress condition at vegetation and flowering stages. The inoculation with Barvar-2 followed by chemical phosphorus by 50 kg ha-1 Triple Super Phosphate significantly increased the amount of anthocyanin and soluble sugars of leaf under drought stress at flowering stage, while the amount of carotenoids and flavonoids, increased with Barvar-2 without using of chemical phosphorus.
    Conclusions
    Our experiment showed that application of chemical phosphorus fertilizer followed by inoculation with Barvar-2 had huge effect on chlorophyll a, chlorophyll b, total chlorophyll, chlorophyll a/ b, carotenoids, fv/fm, anthocyanin, flavonoids and soluble sugars under water stress condition at vegetation and flowering stages. The highest amount of photosynthetic pigment such as anthocyanin, flavonoids, carotenoids and soluble sugars could increases stress tolerance of safflower under water deficit condition. In general, the results of this experiment showed that application of Barvar-2 followed by chemical phosphorus had effective role in improve of qualitative traits of safflower under drought stress condition.
    Keywords: Anthocyanin, Barvar, 2, Chlorophyll, Drought stress, fv, fm
  • A. R. Bolandi, H. Hamidi Pages 318-328
    Introduction
    Introducing potato cultivars with high yield, early maturing and desirable quality have a key role in food security, decreasing the fluctuation of the price and the store costs and also providing fresh crops throughout the year. Potato (Solanum tuberosum L.) plant is one of leading agricultural products in the world with 365 million ton glands in year stands in fourth place after wheat, rice and corn.
    The main objective of the breeding program is yield. Increase in plant yield in the past due to the gradual elimination of defects visible by experts and today the new criteria for selection are based on principles of morphological and functional characteristics associated with the plant. Variety is one of the effective factors on plant growth and development on potato that yields components of potato is heavily dependent on it. Yield increasing in each variety affect the genetic and natural structure of variety.
    Nine clones of Solanum tuberosum L. cv. Kennebec from sources in Victoria, South Australia and Tasmania, and the commercially grown clone, clone 1, which was imported from Vancouver, were multiplied from pathogen-tested seed and compared in 3 Victorian potato districts during 2 seasons. The results showed that differences exist in total and size grade yield and tuber number and appearance between clones of a cultivar. They further highlight the importance of selection work to maintain desirable characteristics of established cultivars and to remove mutants with undesirable characteristics.
    The results of the study, Hassanpanah and Hassanabadi (2012) showed that the clones 397003-7, 396151-27, 397045-100 and Savalan (check) produced higher total and marketable tuber yield, tuber number and weight per plant, plant height, main stem number per plant, tuber size average and stable tuber yield. These clones produced high and mid-uniform tuber, tuber inner crack and tuber inner ring, mid-late maturity and mid and high dry in comparison to those of check. Based on results of this experiment, the clones 397003-7, 396151-27 and 397045-100 could be selected for Ardebil region.
    The objective of this research was to evaluate the quantitative and qualitative traits of cultivars and advanced potato clones in spring cultivation (Jolge-e-Rokh region).
    Materials And Methods
    In this research, 18 potato clones for the quantitative and qualitative traits were compared with three check cultivars including: Agria (suitable for French-fries), Marfona (suitable for boiled eating) and Lady Rosetta (suitable for chips) in Jolge-Rokh Agriculture Research Station, the location 35'¸ 50° north latitude and 59° east longitude and 1721 m above sea level, in crop year 2011. Experimental design was Randomized Complete Block Design (RCBD) with three replications. Treatment consisted of 18 advanced potato clones: 396151-8, 397045-4, 397045-10, TP12-13, TP21-29, TP12-8, 397007-16, 397007-17, 396140-6, 397009-8, 397015-14, 397003-7, 396151-27, 397045-100, 397097-9, 396151-20, 397045-7 and 69 indigenous with three control cultivars (Agria, Marfona and Lady Rosetta). Tubers were planted on two rows with 6 meters length. Distance between row and plants on the row were 75 and 25 cm, respectively. Area of each plot was 9 square meter. The evaluated characters were total yield, marketable yield, eye number, dry matter percentage, tuber number per plant, tuber weight per plant and mean of tuber weight. In order to measure total yield, after maturity, and remove the aerial organs, all of the tubers were harvested and the fresh weight was obtained. After removal of the tumor in bad shape, with soft rot and smaller than 30 mm that cannot be sold as part of the marketable yield, rest of them were used to measure marketable yield. Tuber dry matter percentage (TDM%) was determined from the relationship between fresh and dry weights of sub-sample of 8-10 thinly sliced tubers dried for 48 h at 80° C. Data were analyzed using SAS 9.1 software. The analysis of variance on test data and comparison to the middle of the LSD test was performed at the 5% level.
    Results And Discussion
    The results showed that differences were significant among cultivars and clones in total yield, marketable yield, dry matter percentage, tuber number and weight per plant and mean of tuber weight. Based on the results of the analysis of variance of total tuber yield were observed among the clones, there was significant difference at 1% level. The maximum total yield of tubers related to the 397007-16 clone among the clones and the lowest total yield of tubers, related to the 397097-9 clone. The 397007-16 clone and Marfona cultivar had the highest tuber weight and the 397097-9 clone had the lowest tuber weight. The indigenous 69 and the 397045-10 clones had the highest and lowest number of tuber per plant, respectively. The 69 indigenous clone had the highest amount of dry matter percentage compared to other clones meaning that this clone is suitable for chips production.
    Behjati et al (2013) in their research in order to the evaluation of yield and effective characteristics on yield of promising potato clones, showed a treatment effect on number of tubers per plant, average weight of single tuber per plant, total yield of tubers and marketable tubers yield was significant at 1% level.
    Conclusions
    In general, present results showed that 397007-16 clone was better in tuber weight per plant and total yield compared to other clones.
    Keywords: Dry matter percentage, Eye number, Marketable yield, Total yield, Tuber number
  • S. Heidari, H. Marashi, S. Malekzade Shafaroudi, M. Ghaderi Zafreyi Pages 329-342
    Introduction
    Photosynthetic energy conversion efficiency is characteristic of a system which is determined by interactions between various components of the system. The complex process of photosynthesis has been studied as a whole system which enables in silico examination of a large number of candidate genes for genetic engineering for a higher photosynthetic energy conversion efficiency. One of the most important environmental factors which influence the photosynthesis efficiency is light regime which can cause producing ROS components. To acclimate to such fluctuations, plants have evolved adaptive mechanisms to minimize damage of the photosynthetic apparatus excess light. A fast compatibility response to high light stresses is non-photochemical quenching process (NPQ), dissipating excessive energy to heat. Light harvested state switches into a quenched state by a conformational change of light harvesting complex (LHCII) that regulated by xanthophylls and the PsbS protein within seconds. Low lumen pH activates xanthophyll synthesis via a xanthophyll cycle which consists of the de-epoxidation of violaxanthin to zeaxanthin by violaxanthin de-epoxidase in high light and inversely by zeaxanthin epoxidase in low light which occurs more slowly.
    Materials And Methods
    Thale cress (Arabidopsis thaliana) (Chlombia-0) were grown on soil at 25/22 °C day/night temperature, with a 16/8 h photoperiod, and 40-70% (depend of plant species) relative humidity. The light intensity was 150–200 µE m-2s-1 white light. Intensity of chlorophyll fluorescence was measured with PAM-2000 fluorometer (Heinz Walz, Germany) and the manufacturer’s software (PamWin v.2).
    Results And Discussion
    In the present study, a dynamic kinetics amplified mathematical model was developed based on differential equations in order to predict short-term changes in NPQ in the process of adaptation to different light conditions. We investigated the stationary and dynamic behavior of the model and systematically analyze the dependence of system key characteristic such as rate constant and pool size. For medium and high light intensity, experimental evidence has been predicted with high accuracy by simulation. In low light intensity (100μE m-2s-1) in a few seconds the light phase, a temporary increase in the rate of NPQ was observed after about 60 seconds it reaches to a steady state level. Model simulation of the induction of NPQ relaxation is more accurate than previous predictions, due to the introduction of more stringent quenching agents (xanthophylls cycle and also the light-harvesting complex protonations). The results showed that the pH drop in the transition from darkness to light and high light intensity increases. For low light intensity quenching process occurs with a more gentle slope to the prediction model based on previous experiments is more realistic. In low light conditions, the proton concentration can easily be balanced by ATP synthase activity. This leads to a reduction in current proton-proton feedback gathered during few seconds is balanced. Thus, at high light intensities ATP levels remained stable in the new model is more consistent with reality.
    Conclusions
    A simple mathematical model which has been developed in this paper provides a more detailed description of this process and be able to predict the various components and parameters associated with it. Comparison of simulation results with experimental data revealed that protonated light harvesting complex and Zeaxanthin simultaneously induce NPQ quenching processes. The results can be seen as theoretical basis for developing more accurate models to study molecular mechanisms of acclimation processes of the photosynthetic chain.
    Keywords: Modeling, Non, photochemical Quenching, Photosynthesis
  • A. Rezaei Estakhroeih, B. Babaei Pages 343-353
    Introduction
    Basil (Ocimum basilicum) is an annual plant which belongs to the Lamiaceae family. It used as a drug, spice and fresh vegetable. Drought stress is one of the important limiting factors of plant growth. Water stress has significant effects on morphological and biochemical characteristics of purple Basil. As the soil water content decreases, the plant height, stem diameter, number and area of leaves, leaf area index (LAI), herb yield and leaf chlorophyll contents (a,b and total chlorophyll) decrease, as well. However, the amounts of anthocyanin and proline increase. Cycocel (CCC) which chemically called chlormequat chloride is an alkylating agent and a quaternary ammonium salt.. Cycocel is used as plant growth regulator. Application of Cycocel increases the number of siliques/ plant, seed yield and dry matter produced of oilseed rape. Cycocel application decreases the plant height and increases the yield level and protein percentage of seed in faba bean. This research was performed to investigate the effect of Cycocel on morphological characteristics, the percentage of nitrogen and potassium of basil plants under drought stress conditions
    Materials And Methods
    This research has been conducted in the research station of Shahid Bahonar University of Kerman with 56o 58' E longitude, 30o 15' N latitude, and 1753.8 altitudes. According to the regional information from 1952 to 2005, the average temperature was 17.1 o C, the average rainfall was 154.1 mm, the average annual relative humidity is 32%, and the climate of Kerman according to De Martonne method is semiarid. A split plot experiment based on RCBD with three replications was employed. Three levels of irrigation, including 50 (severe stress) (I3), 75 (mild stress) (I2) and 100 (full irrigation) (I1) percent of crop water requirement were assigned to the main plots while five levels of Cycocel application (zero (control), 500, 1000, 1500, 2000 milligrams per litre) were assigned to the sub-plots. Cultivation was carried out in March and harvested in late June. In this study the plant height, fresh and dry weight of root and shoot, root to shoot dry weight ratio, percentage of nitrogen and potassium, leaf relative water content and leaf area index were measured. For its statistical calculation, SAS (v. 9.1) software and for the comparison of the averages the Duncan’s test was used. The level of possibility used in the analysis was five percent.
    Results And Discussion
    The result of the analysis of variance of measured traits has shown in Table 1. Data analysis of variance (Table 1) shows different levels of irrigation, Cycocel and irrigation with Cycocel interaction were significant at the level of one percent on plant height. Effects of different irrigation treatments and Cycocel concentration on fresh and dry weight of shoot were significant at one and five percent, respectively. However, the effect of irrigation and Cycocel interaction on shoot dry weight was not significant. Root fresh and dry weight were influenced by irrigation levels (Table 1). The effect of irrigation and Cycocel interaction on root dry weight, percent of nitrogen and dry weight of root to shoot ratio was significantat one percent. The effect of irrigation on root to shoot dry weight ratio was not significant. Moreover, the effects of Cycocel treatments on root to shoot dry weight ratio were significant at the five percent level. The effect of irrigation, Cycocel on percent of nitrogen and potassium was significant and potassium decreased with the increasing of water stress.
    The highest percentage of potassium (2.26%) belonged to the full irrigation and the concentration of 2000 milligrams per litre Cycocel and the lowest belonged to the interaction of severe stress and zero, 500 and 1000 milligrams per litre Cycocel. Irrigation and Cycocel had a significant influence on leaf relative water content at the level of one percent.
    Conclusions
    According to the results which obtained through this study, in basil plant, root fresh and dry weight, shoot fresh and dry weight, leaf area index, leaf relative water content and plant height reduced by increasing drought stress. Root-shoot dry weight ratio increased in response to increasing stress in all the plants which treated by Cycocel . Cycocel treatments reduced plant height, root fresh and dry weight, shoot dry weight and LAI. Leaf relative water content and shoot fresh weight increase with increasing the concentrations of Cycocel. The interaction of 2000 milligram Cycocel per litre with irrigation has the greatest effect on the traits.
    Keywords: Basil, Cycocel, Drought stress, Minerals, Morphological traits
  • E. Zeinali, A. Soltani, M. Khadempir Pages 354-368
    Introduction
    Since the leaves are the main source of production of photosynthetic substances in plants, dry matter production and crop yield potential is largely dependent on the leaf surface, and many environmental changes affect growth and yield through changes in leaf area. Hence, green leaf area per plant and leaf area index is measured in almost all studies of crop physiology to understand the mechanism of yield alteration. However, measurement of leaf area compared with the other traits such as plant height and total plant dry weight is very difficult, need to precision instruments and spend more time and cost. Therefore, according to the allometric relationships in plants, extensive studies were done to find the relationship between leaf area and the other plant traits that their measurement is easier, faster and cheaper, and does not require expensive equipment. Using these relationships will be used to estimate plant leaf area with acceptable accuracy without measuring. Plant traits that have high correlation with leaf area and usually use to estimate the plant leaf area are the number of leaves or nodes per main stem, plant height, leaf dry weight and dry weight of vegetative parts of the plant. Allometric equations was used successfully to calculate leaf area for various crops such as cotton, wheat, chickpea, faba bean, peanuts, soybean and sweet sorghum.
    This study was conducted to obtain the allometric relationships between green leaf area (cm2 per plant) with number of leaves or nodes per main stem, plant height, green leaf dry weight and dry weight of vegetative parts of the plant (gram per plant), and investigating the effect of plant density and planting date on these relationships in SC704 corn (Zea mays L.) hybrid.
    Materials And Methods
    This study was conducted at Gorgan University of Agricultural Sciences and Natural Resources farm located at latitude 36 o 51’ N, longitude 54 o27’ E and altitude of 13 meters above sea level in 2012. The experiment was carried out in a randomized complete block design as factorial with three replications. The experimental factors and their levels were, including plant density (4, 6, 8, 10 and 12 plants per square meter) and planting date (May 30 and June 30). Each plot was including 6 rows with 76 cm inter-row spacing and 6 m length. Corn hybrid SC704, a common hybrid in Iran and Gorgan region, was used in this study. Plant sampling was carried out once every 10 days from 15 days after planting to physiological maturity to measure leaf dry weight, plant green leaf area, the leaf (node) number per stem, dry weight of total vegetative plant parts and plant height. Green leaf area was measured using leaf area meter in laboratory. Plant samples were placed in an oven with 70 oC for 48 hours. To obtain allometric relationships various mathematical equations fitted to green leaf area against mentioned traits data. Fitting the functions to data and examining them was carried out in three steps: 1) Fitting function to each of the plant density in each planting date, 2) Fitting a function to all plant densities in each of two planting dates, separately, and 3) Fitting a function to all data. At each step, after fitting the functions and analysis of coefficients, if the differences were not significant, the next step was used. Statistical analysis was done using the software SAS and the graphs drew using Excel software.
    Results And Discussion
    The results showed that a non-linear segmented model can be used to describe the relationships between the number of leaves per stem with cumulative thermal units (R2= 0.94, RMSE =5.59%), and leaf area per plant with leaf dry weight per plant (R2= 0.98, RMSE =6.54%) and plant dry weight (R2= 0.95, RMSE =11.25%) in all plant densities and planting dates. Moreover, the results revealed that the effect of planting date and plant density on the phyllochron, time between the appearance of successive leaves on a shoot was not significant, and mean of the phyllochron was 72.33 thermal units in all treatments. In addition, the findings of this study indicated the significant effect of planting date and non-significant effect of plant densities on the relationship between leaf area per plant and number of leaves (nodes) per stem. Therefore, two individual power equations with R2= 0.99 (Y= X3.36 and Y= X0.286 for the first and second planting date, respectively) applied to describe this relationship in two planting dates. Similarly, a power equation (Y = X0.14, R2= 0.99) can be used to describe the relationship between leaf area index and plant height in all planting dates and densities.
    Conclusions
    Findings of this study showed that the obtained functions to describe the relationship between the leaf area have high accuracy to estimate green leaf area per plant. But among these relationships, relationships between plant green leaf area with plant green leaf dry weight and plant height had higher coefficient of determination, smaller root mean square, and subsequently higher estimation accuracy. Therefore, using these two traits, leaf area can be estimated more accurately. Moreover, since the relationship between green leaf area with green leaf dry weight per plant was more accurate than plant height, using this relationship in corn simulation models and for fast and easy estimating of leaf area, especially when the leaf area meter is not available, is recommended.
    Keywords: Allometric relationships, Corn, Leaf area, Vegetative characteristics
  • E. Izadi, Darbandi, A. Nezami, R. Hassanbeigy, M. Janalizadeh Ghazvini Pages 369-379
    Introduction
    Flixweed (Descurainia sophia L.) is a medicinal plant from Brassicaceae family which also known as a weed for winter cereals and oil seed rape. Low temperatures are one of the most important abiotic stresses that threat Flixweed growth and productivity. Therefore it is important to recognize the freeze tolerance of Flixweed for successful planting and utilization in cold regions such as Mashhad in Khorasan Razavi Province (Iran’s north. east). Among many laboratory methods which have been developed to estimate and to evaluate plants response or their tolerance to freez¬ing temperatures, electrolyte leakage (EL) test is widely used. This test is based on this principle that damage to the cell membranes results in enhanced leakage of solutes into the apoplastic water, hence recording the amount of leakage after stress treatments provides an estimation of tissue injury. Indeed continuing integration of plasma membrane is one important factor for survival of plants under freezing stress and any disturbance in membrane structure can lead to damage and death. So determination of LT50 point or critical temperature for electrolytes leakage and survival of plant is the most reliable, quantitative and simple methods for evaluating the cold tolerance of plants. The aim of this trial was to determine the LT50 according to the EL and SU% for Flixweed ecotypes.
    Materials And Methods
    In order to evaluate freeze tolerance in Flixweed, a factorial experiment based on completely randomized design with three replications was carried out in college of agriculture, Ferdowsi University of Mashhad. Experimental factors included five ecotypes of Flixweed (Eghlid, Sabzewar, Hamedan, Torbat-e-Jam and Neyshabour) and 10 freezing temperature levels (0, -2,-4, -6, -8,-10,-12,-14,-16 and -18°C). Flixweed seeds were cultivated in pots in autumn of 2008 and were grown until 5-7 leaf stage under natural weather conditions for acclimation. Then to apply freezing temperatures, they were transferred to a thermo gradient freezer. The initial temperature of programmable freezer was 5°C; but gradually decreased in a rate of 2°C.h-1 until reached to desired temperatures. When the temperature reached to -2°C, the plants were sprayed with the Ice Nucleation Active Bacteria (INAB) to help the formation of ice nucleus in them. As well this spraying was conducted to prevent from super-cooling of samples and to ensure that mechanism of freeze resistance is tolerance not avoidance as well. After reaching a desired freezing temperature happened, the samples were removed from the freezer and then were thawed slowly during 24 hours in a refrigerator at 5±1°C. Cytoplasmic membrane stability was evaluated by electrolyte leakage (EL) test, afterward lethal temperature was calculated for 50% of plants according to the electrolyte leakage % (LT50el). In order to evaluate correlation between EL% with survival percentage (SU%), remained plants were transferred to greenhouse and after 21 days recovery, SU% and then lethal temperature was determined for 50% of plants according to the SU% (LT50su). Analysis of variance performed by MSTAT-C software and correlation between data carried out by MINITAB 16 program. LT50el was determined by Slide write software. Mean separation was conducted by least significant difference (LSD) test at 1% probability level.
    Results And Discussion
    Results showed that the reduction of temperature to less than -8°C, led to increment of electrolyte leakage % and decline of survival %. Interaction effect of ecotype and temperature on electrolyte leakage and survival percentage was significant at 1% probability level. Enhancement of electrolyte leakage % for Neyshabour ecotype started from -8°C, while the others were affected from lower temperatures. In addition in Eghlid and Neyshabour ecotypes, decline of survival % begun from higher temperatures (-8 °C) compared with the other ecotypes (-10 °C). Cold hardiness is often reported as LT50el, means the temperature at which 50% of the electrolytes leaked from the cells. LT50el often is simply equaled to 50% sample mortality or LT50su. According to the LT50el and LT50su indices, Hamedan, Sabzewar and Torbat-e-Jam ecotypes had better freeze tolerance than Neyshabour and Eghlid ecotypes and according to the LT50su, Hamedan ecotype had potential to freezing tolerance up to -12°C.
    Conclusions
    In this survey, there was strong and negative correlation between EL% and SU% (r= -0.72***). Furthermore, there was high and positive correlation between LT50el and LT50su (r= 0.53*). These results indicate efficiency and alternative likelihood of each index in assessment of Flixweed freeze tolerance. Regarding to more rapid rate of EL method compared to SU evaluation, it seems better to utilize of this index.
    Keywords: Ecotype, LT50, Recovery, Survival percentage
  • Gh Mahmoudi, A. Ghanbari, M. Rastgoo, M. Gholi Zade, I. Tahmasebi Pages 380-391
    Introduction
    Effect of magnetic fields is now the subject of an increasingly large research effort because it is known to induce biochemical changes in plant species. In physic science, it is well established that by passing water through a magnetic device, the water can be influenced. On the other hand, the literature review in physical science in different country indicated also that magnetized water induced a change in water physicochemical properties such as conductivity, surface tension, viscosity, vaporization rate, and pH. The magnetic properties of the cells determine their capability in order to absorb and transfer the magnetic energy to other types of energy, transferring these energies within the plant. Therefore, this technology was used in different countries which all reported the successful use of magnets in treating water for irrigation use. Magnetic fields on seeds lead to better germination rate and plant growth than chemical fertilizers. Magnetic fields have been to apply a stimulus effect on growth and germination and on crop yield.
    Materials And Methods
    In order to study the effect of magnetic field on growth and total dry matter of chickpea (Cicer arietinum L.), an strip plot experiment based on randomized complete block design was conducted at the Agronomy Research Field of Ferdowsi University of Mashhad ( Lat 36˚15' N, Long 59˚28' E; 985 m Altitude) during 2013-2014. The first treatment was the exposure of seed to magnetic field in three levels (normal, 100 and 150 mT magnetic field with 120 minutes durations).The magnetic field exert by a device consists of two magnets and the two opposite poles of two magnets that attract each other. Moreover, the intensity of magnetic field changed by adjusting the distance between the poles. It was measured by using a micrometer Tesla meter Leybold- Heraeus51652. The second treatment consisted of water irrigation types as two levels (normal water and magnetized water with 650 mT). Magnetized water was produced by a commercial magnet namely AQUA CORRECT with (650Gauss magnetic field. All data were analyzed by Sigmaplot and Excel and treatments were separated using Fisher’s protected LSD Test. All statements of significance were based on probability of (P
    Keywords: Magnetic irrigation, Seed yield, Sigmoid equation
  • A. H. Jalali Pages 392-402
    Introduction
    Potato (Solanum tuberosum ssp.) is an autotetraploid (2n=4x=24) species and a key member of the Solanaceae family. Physiological age is usually be determined from potato tuber initiation and afterwards. Potato seed tubers physiological preparedness for growth is an important factor in determining the productive potential of the seed potatoes. Physiological age is considered as an internal biological clock that usually covers all aspects of the production while chronological age is determined only by the length of harvest and planting time (Gregory, 1985). In most cases, the current practice for storing potato tubers is to wound-heal seed-tubers at 10-15º C during the initial l0 days of storage (Curing) and then reduce and maintain the temperature at a holding level of 4 ° C until planting while the technique of physiological aging of seed tubers, was not only one tuber storage temperature (4°C) and then transferred to a higher temperature (similar natural germination conditions), but different thermal treatments during storage conditions is used in order to increase the physiological age. Some researchers argue that thermal storage is essential to obtain quantitative and qualitative performance which its value is higher than 250 GDD. The physiological age of seed tubers 900-600 GDD in some studies to increase performance by 90 percent and was associated uniformity producing tubers..In temperate regions with spring planting date, the short growing season and high summer temperature is considered as limiting factor for potato production. For this purpose the present study was carried out to evaluate the effect of different storage temperatures on the physiological age of seed and its effect on yield and earliness of two potato cultivars.
    Materials And Methods
    The Effects of six different thermal treatments storage in a three-month period, including two treatments of 440 degree- day (T1 and T2), two treatments of 880 degree-day (T3 and T4), one treatment of 80 degree-day (T5), and control treatment (T6) on agronomic characteristics and yield of Marfona and Ramus cultivars was investigated by using a factorial experiment based on randomized complete block design with four replications at Kabootar Abad Agriculture Research Center of Isfahan. Period of 10 days and 12 ° C were found in all treatments. For example, in the treatment of T3, the tissue repair process that is carried out for 10 days at 12 ° C to 80 GDD is received by the tubers (8 × 10, 8 for the reason that, 4 ° C is base temperature and should be minus of 12). Salable and non-salable yield, number of stems produced, emergence rate, the number of tubers per plant, tubers weight and the tubers size were measured in this study.
    Results And Discussion
    The results of this study showed that the effect of temperature treatment and the interaction of temperature treatment and cultivar on yield and yield components were considered statistically significant. Marfona cultivar and use of T3 treatment with 51733 kg ha-1 had the highest tuber yield. However, there was not significant difference between this treatment and use of T2 treatment, and also using of Ramus cultivar and T3 and T4 temperature storage. For both cultivars used in this study, T3 treatment produced maximum number of stems per plant. Harvest index was fluctuated at different temperature treatments from 63.5 to 76.1 percent in the Ramos cultivar, and from 64 to 79.6 percent in Marfona cultivar. In summary, management of storage temperature can increase potato crop yields, especially in areas with short growing seasons. It seems that effects of physiological age differ between cultivars and different varieties of potatoes have different abilities to produce tuber yields in response to different heat treatments. Increasing of total tuber yield, especially as affected by thermal temperature storage application higher than 500 GDD was reported in some studies such as Knowles and Botar (1992) in which plants from 341GDD seed tubers produced 70% of their total yield as marketable, while 64% of the total yield from 900 GDD seed tubers was graded as marketable. The harvest index is a change in potatoes varieties from 9% in the wild up to 81 percent of in new cultivars, respectively. But harvest index is usually considered to be 75% for new potato varieties.
    Conclusions
    The results of this study indicated that compared with younger tubers, the yield increased from older seed tubers but it must stress that the proper seed tuber age depends upon cultivar. With using of “controlled seed-tuber aging” techniques, process of plant development was accelerating and thus tuber set and tuber enlargement faced with optimum environmental conditions. This technique can be used in the following cases: when sowing date delayed and need to quickly grow, when a farmer or a company producing seed tuber for short growing season.
    Keywords: Growth Degree day (GDD), Leaf Area Index (LAI), Physiological Age