فهرست مطالب

  • سال هفدهم شماره 2 (1398)
  • تاریخ انتشار: 1398/03/27
  • تعداد عناوین: 12
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  • حامد جوادی، پرویز رضوانی مقدم*، محمد حسن راشد محصل، محمد جواد ثقه الاسلامی صفحات 187-205

    به منظور بررسی مدیریت کود بر برخی خصوصیات شیمیایی خاک و جذب عناصر نیتروژن و فسفر توسط خرفه، دو آزمایش جداگانه در دو سال زراعی 94-1393 و 95-1394 در مزرعه تحقیقاتی دانشگاه بیرجند با سه تکرار انجام شد. در آزمایش اول که به صورت کرت های خردشده در قالب طرح بلوک های کامل تصادفی اجرا شد، چهار کود سبز شامل: شاهد (بدون کود سبز)، ماشک گل خوشه ای (Vicia villosa L.)، منداب (Eruca sativa L.) و مخلوط منداب و ماشک گل خوشه ای به عنوان عامل اصلی و سه سطح کود نیتروژن به صورت خالص شامل: صفر (شاهد)، 50 و 100 کیلوگرم در هکتار به عنوان عامل فرعی بودند. در آزمایش دوم که به صورت فاکتوریل در قالب طرح بلوک های کامل تصادفی انجام شد، تیمارهای آزمایش بر اساس ترکیبی از چهار منبع تامین کننده نیتروژن شامل: کود گاوی، ورمی کمپوست، کود شیمیایی (NPK) و شاهد (بدون اعمال هیچ گونه کودی) و نیز چهار نوع کود زیستی شامل: نیتروکسین (شامل ازتوباکتر و آزوسپیریلوم)، میکوریزا (Glomus intraradices)، بیوسولفور (شامل تیوباسیلوس همراه با گوگرد) و شاهد (بدون هیچ گونه کودی) بودند. صفات مورد مطالعه در این آزمایش شامل: درصد کربن آلی و نیتروژن خاک، میزان فسفر قابل جذب خاک، pH و EC خاک و درصد نیتروژن و فسفر زیست توده بودند. نتایج نشان داد که استفاده از کود سبز باعث افزایش درصد کربن آلی، نیتروژن خاک و میزان فسفر قابل جذب خاک و کاهش pH خاک شد. از بین تیمارهای کود سبز مورد مطالعه ماشک گل خوشه ای نسبت به سایرین برتر بود. همچنین، استفاده از کود نیتروژن باعث افزایش میزان فسفر قابل جذب، هدایت الکتریکی خاک و عملکرد دانه و کاهش pH خاک شد. در بین منابع تامین کننده نیتروژن، تیمار کود گاوی بیشترین تاثیر را بر درصد کربن آلی، درصد نیتروژن و میزان فسفر قابل جذب خاک داشت. استفاده از کود شیمیایی (NPK) و کود گاوی نسبت به شاهد باعث افزایش 04/16 و 37/10 درصدی عملکرد دانه شد. اما نقش کاربرد کودهای زیستی به افزایش میزان فسفر قابل جذب خاک محدود شد. با توجه به اثر مثبت کودهای آلی و زیستی بر برخی خصوصیات شیمیایی خاک، بیشترین درصد نیتروژن زیست توده خرفه از تیمار مخلوط منداب و ماشک گل خوشه ای و تیمار تلفیق کود گاوی و میکوریزا حاصل شد. همچنین، بیشترین درصد فسفر زیست توده خرفه متعلق به تیمار تلفیق کود گاوی و میکوریزا بود.

    کلیدواژگان: بیوسولفور، کود گاوی، میکوریزا، نیتروکسین، ورمی کمپوست
  • محسن جهان*، مهدی نصیری محلاتی صفحات 207-220

    پژوهش حاضر با هدف فراتحلیل نتایج پژوهش های صورت گرفته در کشور و پاسخ به این سوال کلی که آیا کاربرد این مواد به طور کلی موفقیت آمیز بوده یا خیر و اگر موفق بوده چه مقدار از آن قابل توصیه است، صورت گرفت. برای انجام این پژوهش، مقاله های منتشرشده با موضوع تاثیر مقادیر مختلف سوپرجاذب رطوبت بر عملکرد و اجزای عملکرد گیاهان زراعی (شامل غلات، حبوبات، گیاهان دارویی و مرتعی) مورد بررسی قرار گرفتند. نتیجه فراتحلیل نشان داد که میانگین مصرف سوپرجاذب برای غلات، گیاهان دارویی، حبوبات و گیاهان مرتعی به ترتیب، 83، 322، 1031 و 210 کیلوگرم در هکتار بود و با مصرف این مقدار سوپرجاذب، میانگین عملکرد دانه در غلات، گیاهان دارویی و حبوبات در مقایسه با تیمار شاهد، به ترتیب 2/13، 2/11 و 5/27 درصد (معادل 1059، 345 و 452 کیلوگرم در هکتار) افزایش یافت. به طورکلی، نتایج نشان داد که تاثیر سوپرجاذب بر عملکرد دانه و ماده خشک معنی دار و بر شاخص برداشت ناچیز است. اندازه اثر کاربرد سطوح مختلف سوپرجاذب بر عملکرد ماده خشک در تمام سطوح بیشتر از اندازه اثر آن بر عملکرد دانه بود. بیشترین اندازه اثر بر عملکرد دانه، مربوط به مصرف 100 کیلوگرم سوپرجاذب در هکتار بود و مقادیر بیشتر از 200 کیلوگرم در هکتار، بر خلاف عملکرد ماده خشک، تاثیر قابل توجهی بر عملکرد دانه نداشت. با توجه به نتایج، به نظر می رسد که کاربرد 100 کیلوگرم سوپرجاذب در هکتار از نظر میزان تاثیر بر افزایش عملکرد دانه و ماده خشک و جنبه اقتصادی، مناسب ترین مقدار باشد.

    کلیدواژگان: حبوبات، غلات، گیاهان دارویی، متاآنالیز
  • ولی فیضی اصل*، امیر فتوت، علی رضا آستارایی، امیر لکزیان، جعفر جعفرزاده صفحات 221-240

    امروزه تشخیص گیاه مبنا یکی از مهم ترین روش های تعیین وضعیت نیتروژن در گیاه می باشد. به منظور برقراری ارتباط بین داده های حاصل از کلروفیل متر و وضعیت نیتروژن در ژنوتیپ های گندم دیم در مدیریت های مختلف مصرف نیتروژن به عنوان ابزاری جهت دستیابی به عملکردهای مطلوب، آزمایشی به صورت کرت های دوبارخردشده در قالب طرح بلوک های کامل تصادفی در سه تکرار در سال زراعی 90-1389 در موسسه تحقیقات کشاورزی دیم مراغه به اجرا درآمد. آزمایش شامل زمان مصرف نیتروژن (کل نیتروژن مصرفی در پاییز و مصرف تقسیطی آن به صورت  در پاییز و  در بهار در مرحله ZGS32) به عنوان عامل اصلی، چهار سطح نیتروژن (صفر، 30، 60 و 90 کیلوگرم نیتروژن در هکتار) به عنوان عامل فرعی اول و 7 ژنوتیپ گندم دیم به عنوان عامل فرعی دوم بود. در مراحل شروع پنجه (GS22)، پنجه کامل (GS29)، طویل شدن ساقه (GS32)، ظهور برگ پرچم (GS39) و گلدهی (GS60)، شاخص نسبی کلروفیل با استفاده از دستگاه SPAD قرائت و با اجزای کلروفیل کل، کلروفیل a، کلروفیل b، کلروفیل c و کاراتنوئیدهای اندازه گیری شده در شرایط آزمایشگاهی برازش داده شد. نتایج نشان داد، شاخص کلروفیل همبستگی مثبت و معنی داری با کلروفیل کل، کلروفیل a، کلروفیل b، کلروفیل c و کاراتنوئیدها داشت. مصرف تقسیطی نیتروژن توانست شاخص کلروفیل (3/8 درصد) و اجزای کلروفیل (کلروفیل کل، a، b و c به ترتیب 0/15، 1/11، 9/10 و 0/27 درصد) و پروتئین دانه (5/8 درصد) را به استثنای کاراتنوئیدها به طور معنی داری افزایش دهد. مصرف نیتروژن توانست تمامی شاخص های کلروفیل را در گیاه تحت تاثیر قرار داده و به طور معنی داری آنها را تغییر دهد. ایده آل ترین شرایط از لحاظ شاخص های کلروفیل در گیاه با مصرف 72 کیلوگرم نیتروژن در هکتار به دست آمد. ژنوتیپ 1 مطلوب ترین و آذر 2 نامناسب ترین وضعیت را از لحاظ شاخص های کلروفیل و نسبت کلروفیل کل به کاراتنوئیدها (مطلوب 70-40) در گیاه به عنوان شاخص مقاومت به تنش به خود اختصاص دادند.

    کلیدواژگان: اجزای کلروفیل، تنش رطوبتی، روش بای پلات، مراحل رشد، مصرف اقتصادی نیتروژن
  • شیوا محمدنیا، علی اصغری*، داوود حسن پناه، رحمت الله کریمی زاده، علی اکبر شکوهیان صفحات 241-253

    این پژوهش به منظور دستیابی به هیبریدهای مناسب از نظر صفات زراعی با شرایط اقلیمی مناطق تولید سیب زمینی کشور اجرا شد. تعداد 20 هیبرید سیب زمینی همراه با پنج رقم تجاری (ساوالان، آگریا، کایزر، لوتا و ساتینا)، در آزمایشی بر اساس طرح بلوک های کامل تصادفی با سه تکرار در ایستگاه های تحقیقات کشاورزی و منابع طبیعی اردبیل، خراسان رضوی، کرج، اصفهان و همدان در سال 94-1395 ارزیابی گردیدند. در طول دوره ی رشد و پس از برداشت محصول برخی از صفات از جمله ارتفاع بوته، تعداد روز تا غده زایی، تعداد ساقه اصلی در بوته، تعداد و وزن غده در بوته، عملکرد غده کل و درصد ماده خشک غده اندازه گیری شدند. نتایج تجزیه واریانس مرکب صفات مورد ارزیابی نشان داد که بین هیبریدهای سیب زمینی از لحاظ تمام صفات اختلاف معنی دار وجود دارد و اثر متقابل هیبرید × محیط در صفات ارتفاع بوته، تعداد روز تا غده زایی، تعداد و وزن غده در بوته، عملکرد غده کل و درصد ماده خشک غده معنی دار بود. هیبریدهای 5، 9، 17 و 19 بیشترین عملکرد غده کل و هیبرید 20 و رقم ساتینا دارای کمترین وزن غده در بوته بودند. در تجزیه عامل ها، 3 عامل مستقل از هم 74/75 درصد از تنوع را توجیه نمودند. عامل اول, عامل عملکرد عامل دوم، عامل غده زایی و عامل سوم عامل ساختاری بوته نام گذاری شد. سه عامل اول برای گروه بندی هیبریدها مورد استفاده قرار گرفتند. هیبریدهای 5، 17 و 19 به عنوان هیبرید برتر انتخاب گردید. هیبریدهای 1، 3 و 20 با دارا بودن بیشترین درصد ماده خشک برای فرآوری (چیپس) قابل توصیه می باشد. صفت وزن غده در بوته و تعداد غده در بوته دارای بیشترین شاخص پیشرفت ژنتیکی، وراثت پذیری، ضریب تغییرات ژنتیکی و فنوتیپی بودند. لذا، می توان این صفات را در برنامه های اصلاحی از طریق گزینش بهبود داد.

    کلیدواژگان: پارامترهای ژنتیکی، پیشرفت ژنتیکی، سیب زمینی، عملکرد، هیبرید، وراثت پذیری
  • ناصر مجنون حسینی، محمدحسین نعیمی، مصطفی اویسی* صفحات 255-264

    گیاه دارویی گل سازویی (Scrophularia striata) با نام محلی تشنه داری، گیاهی خودرو، چندساله و بومی ایران می باشد. یک مطالعه مزرعه ای به منظور شناخت بهترین بستر و تاریخ کاشت برای این گیاه و بررسی تاثیر این دو فاکتور روی تقویم رشد (فنولوژی) این گیاه به صورت طرح کرت های خردشده در قالب بلوک کامل تصادفی با سه تکرار انجام شد. کرت‎های اصلی شامل تیمارهای تاریخ کاشت در پنج سطح]پانزدهم ماه های خرداد (D1)، شهریور (D2)، مهر (D3)، آبان (D4) و اسفند (D5)[و کرت‎های فرعی شامل بسترهای مختلف کاشت]پیت ماس، پیت ماس+ پرلیت (1:1) و کوکوپیت + پیت ماس+ پرلیت (1:1:2)[در نظر گرفته شدند. نتایج حاصل از بررسی میزان درجه روز رشد (GDD) مورد نیاز برای رسیدن به مراحل مختلف فنولوژیک گل سازویی (گره اول و دوم ساقه، گل دهی، کپسول دهی، دانه بندی و رسیدگی) نشان دادند که در تیمار تاریخ کاشت خردادماه،گیاهان کمترین مقدار GDD را در بستر کاشت پیت ماس داشتند. با تاخیر تاریخ کاشت به سمت آبان ماه، گیاهان به GDD بیشتری برای مراحل مختلف فنولوژیک نیاز داشتند. در تاریخ کاشت اسفندماه نیز گیاهان درمرحله رویشی باقی ماندند و نتوانستند وارد مرحله زایشی شوند، که نشانگر نیاز گل سازویی به سرما برای ورود به فاز زایشی می باشد. بر اساس نتایج این تحقیق، خرداد ماه به عنوان مناسب ترین زمان برای کاشت گل سازویی تعیین شد. این نتایج می تواند در راستای اهلی سازی و کشت زراعی این گیاه اطلاعات مناسبی در اختیار بهره برداران قرار دهد.

    کلیدواژگان: اهلی سازی، درجه روز رشد، گیاه بومی
  • سیاوش برده جی*، محمد بنایان، قربان علی اسدی صفحات 265-273

    به منظور بررسی تاثیر سطوح مختلف آبیاری و مالچ پلاستیکی بر عملکرد و اجزای عملکرد کدو پوست کاغذی و تاثیر مالچ پلاستیکی بر تعدیل اثر تنش خشکی، آزمایشی درسال زراعی 1394 به صورت اسپلیت پلات در قالب طرح بلوک های کامل تصادفی در سه تکرار در مزرعه تحقیقاتی دانشکده کشاورزی دانشگاه فردوسی مشهد انجام شد. عوامل آزمایش شامل سه سطح آبیاری (50، 75 و 100 درصد نیاز آبی) به عنوان کرت اصلی و دو سطح مالچ پلاستیکی تیره رنگ (وجود و عدم وجود مالچ) به عنوان کرت فرعی در نظر گرفته شدند. نتایج نشان داد که تغییرات آبیاری در تمام صفات مورد مطالعه به تغییر معنی دار(P <0.01)  منجر شد. همچنین کاهش 50 درصدی در میزان آبیاری باعث کاهش 68 درصدی عملکرد میوه در مقایسه با شاهد شد. تیمار مالچ تاثیر معنی داری بر ماده خشک کل، شاخص سطح برگ، عملکرد میوه، عملکرد دانه، شاخص برداشت و وزن هزار دانه نشان داد. برهمکنش آبیاری و مالچ پلاستیکی نیز اثر معنی داری بر ماده خشک، شاخص سطح برگ، شاخص برداشت و عملکرد میوه و دانه داشت. استفاده از مالچ باعث افزایش 7/14، 2/97 و 1/314 درصدی عملکرد دانه به ترتیب در آبیاری نرمال، 75 و 50 درصد نیاز آبی گیاه شد. به طورکلی، نتایج نشان داد که انجام آبیاری بر اساس نیاز آبی گیاه می تواند نقش مهمی در افزایش عملکرد و اجزای عملکرد کدو پوست کاغذی داشته باشد و با توجه به اینکه بین تیمار 75 درصد نیاز آبی و تیمار آبیاری نرمال تفاوت معنی داری وجود نداشت، اعمال آبیاری به میزان 75 درصد نیاز آبی گیاه و کاربرد مالچ می تواند راهکار مناسبی در شرایط کم آبی باشد.

    کلیدواژگان: خاک پوش، عملکرد دانه، عملکرد میوه، کم آبی
  • روژین قبادی، مختار قبادی*، سعید جلالی هنرمند، بهمن فرهادی، فرزاد مندنی صفحات 275-289

    به منظور بررسی همبستگی و روابط علت و معلولی بین برخی از صفات با عملکرد ذرت دانه ای سینگل کراس 704 در شرایط مختلف آبیاری و نیتروژن، آزمایشی به صورت کرت های یک بار خرد شده طی دو سال در دانشگاه رازی اجرا شد. فاکتور اصلی، آبیاری (تامین 60، 80، 100 و 120 درصد نیاز آبی) و فاکتور فرعی، نیتروژن (تامین 40، 70، 100 و 140 درصد نیاز گیاه) بود. نتایج همبستگی، رگرسیون گام به گام و تجزیه علیت تا حدی موید یکدیگر بودند و نشان دادند که روابط صفات با عملکرد دانه تحت تاثیر وضعیت دسترسی به آب و نیتروژن قرار می گیرد. در تمام شرایط محیطی، صفات وارد شده به مدل های رگرسیونی بیش از 95 درصد از تغییرات عملکرد دانه را توجیه کردند. بر اساس نتایج تجزیه علیت، در شرایط بیش آبیاری و آبیاری کامل، وزن صد دانه و تعداد دانه در ردیف، در تنش ملایم کم آبی، وزن صد دانه و ارتفاع بوته و در تنش شدید کم آبی، عمق دانه و فاصله گرده افشانی تا کاکلدهی به دلیل اثرات مستقیم و غیر مستقیم قابل توجه بر عملکرد، به عنوان شاخص های مناسبی جهت بهبود عملکرد دانه معرفی شدند. در تمام سطوح نیتروژن، انتخاب بر اساس وزن خشک کل و شاخص برداشت مفید خواهد بود. تعداد دانه در ردیف و وزن صد دانه نیز به دلیل اثرات غیر مستقیم بالا بر عملکرد دانه در برخی از سطوح نیتروژن باید مورد توجه قرار گیرند.

    کلیدواژگان: رگرسیون گام به گام، عملکرد دانه، کم آبی، متغیر مستقل
  • سید عطااله سیادت، ابوالفضل درخشان* صفحات 291-303

    زیست توده گیاهی بالای سطح زمین را می توان به صورت حاصل ضرب تابش تجمعی دریافت شده (IPAR) توسط سایه انداز گیاهی و کارایی استفاده از تابش (RUE) بیان نمود. در این مطالعه تاثیر تیمارهای مصرف نیتروژن (N) بر IPAR و RUE دو رقم کلزای بهاره (Hyola 401 و دلگان) بررسی شد. آزمایش مزرعه ای در سال زراعی 96-1395 به صورت کرت های خردشده در قالب طرح پایه بلوک های کامل تصادفی با سه تکرار در مزرعه پژوهشی دانشگاه علوم کشاورزی و منابع طبیعی خوزستان اجرا شد. میزان مصرف N در هفت سطح صفر، 50، 100، 150، 200، 250 و 300 کیلوگرم در هکتار به عنوان عامل اصلی و نوع رقم کلزا در دو سطح به عنوان عامل فرعی در نظر گرفته شد. نتایج نشان داد که پاسخ زیست توده بالای سطح زمین به فراهمی N در هر دو رقم کلزای مطالعه شده به تغییر هردوی IPAR و RUE مربوط بود. کل IPAR تجمعی در طی دوره رشد در دو رقم Hyola 401 و دلگان در شرایط مصرف 200 کیلوگرم N در هکتار به ترتیب در حدود 27 و 35 درصد بیشتر از تیمار شاهد بود. در هر دو رقم کلزا، IPAR به شدت به LAI و LAD وابسته بود. به این معنی که، مصرف N با افزایش LAI و LAD منجر به افزایش IPAR شد. مصرف N تاثیری بر ضریب استهلاک نوری (K) سایه انداز گیاهی نداشت و این ضریب برای رقم Hyola 401 معادل 65/0 (± 02/0) و برای رقم دلگان معادل 73/0 (± 02/0) برآورد شد. بسته به فراهمی N، برآورد RUE برای رقم دلگان بین 02/2 (تیمار شاهد) تا 25/3 گرم بر مگاژول (200 کیلوگرم N در هکتار) و برای رقم Hyola 401 بین 86/1 (تیمار شاهد) تا 62/3 گرم بر مگاژول (300 کیلوگرم N در هکتار) متغیر بود.

    کلیدواژگان: دوام سطح برگ، سرعت رشد محصول، شاخص سطح برگ، ضریب استهلاک نور، کسر تابش دریافت شده
  • عبداله ساجدی*، نورعلی ساجدی صفحات 305-316

    به منظور بررسی تاثیر بیوچار و پرایمینگ بذر با آب و سالیسیلیک اسید توام با محلول پاشی بر عملکرد، اجزای عملکرد و درصد روغن گلرنگ در شرایط دیم، آزمایشی به صورت اسپلیت- اسپلیت پلات در قالب طرح بلوک های کامل تصادفی در سه تکرار در سال 96-1395 در مزرعه تحقیقاتی دانشگاه آزاد اسلامی اراک انجام شد. عوامل آزمایشی شامل بیوچار در سه سطح (عدم مصرف، 5 و10 تن در هکتار)، پرایمینگ بذر در سه سطح (بدون پرایمینگ، پرایمینگ بذر با آب مقطر و پرایمینگ بذر با محلول 5/0 میلی مولار سالیسیلیک اسید) و محلول پاشی در دو سطح (با آب و محلول 1 میلی مولار سالیسیلیک اسید) بودند. نتایج نشان داد با مصرف 5 و 10 تن در هکتار بیوچار، درصد ظهور گیاهچه نسبت به شاهد به ترتیب 7/23 و 4/40 درصد افزایش یافت. پرایمینگ بذر همراه محلول پاشی با آب تعداد طبق بارور در بوته را نسبت به شاهد 9/13 درصد افزایش داد. بیشترین تعداد دانه در طبق از مصرف 5 تن در هکتار بیوچار و پرایمینگ با آب مقطر حاصل شد. با مصرف 5 تن در هکتار بیوچار همراه پرایمینگ با آب یا سالیسیلیک اسید، عملکرد دانه به ترتیب 4/22 و 7/8 درصد نسبت به شاهد (عدم پرایمینگ و عدم مصرف بیوچار) افزایش یافت. بیشترین درصد روغن از مصرف 5 تن در هکتار بیوچار و پرایمینگ با آب توام با محلول پاشی با سالیسیلیک اسید حاصل شد. به طور کلی نتایج نشان داد که با مصرف 5 تن در هکتار بیوچار و پرایمینگ با آب توام با محلول پاشی می توان به عملکرد کمی و کیفی مطلوب گلرنگ در شرایط دیم دست یافت.

    کلیدواژگان: اجزای عملکرد، پیش تیمار بذر، درصد روغن، دانه روغنی، کشت دیم
  • منوچهر شیری*، مرتضی کامرانی، اصغر مهربان صفحات 317-326

    به منظور بررسی نقش کودهای نانو کلات آهن و روی بر عملکرد و غلضت عناصر دانه ارقام دیم گندم نان، آزمایشی در سال زراعی 95-1394 در مزرعه مرکز تحقیقات کشاورزی و منابع طبیعی مغان به صورت فاکتوریل بر پایه طرح بلوک های کامل تصادفی با 3 تکرار به اجرا درآمد. عامل اول محلول پاشی در چهار سطح شامل شاهد و محلول پاشی با آهن، روی و آهن + روی بودند و عامل دوم ارقام در چهار سطح شامل دو رقم آفتاب (G1)، کریم (G2) و دو ژنوتیپ جدید (G3 و G4) بودند. غلظت محلول پاشی آهن و روی به ترتیب با نسبت 2 و 5/1 در هزار در سه مرحله پنجه دهی، اوایل سنبله دهی و شیری بودن دانه ها صورت گرفت. ویژگی های مورد مطالعه شامل تعداد سنبلچه در سنبله، تعداد دانه در سنبله، تعداد دانه در سنبلچه، و وزن هزار دانه در سنبله اصلی، عملکرد دانه در متر مربع، غلظت روی، غلظت آهن، مقدار اسید فیتیک و نسبت مولی اسید فیتیک به روی و آهن دانه بودند. نتایج نشان داد که رقم G3 به همراه ژنوتیپ G2 و G4 نسبت به رقم G1 به طور معنی داری عملکرد بیشتر تولید کردند. این افزایش عملکرد عمدتا به علت تعداد سنبلچه بیشتر، تعداد دانه در سنبلچه بیشتر و یا هر دو بود. ارقام G1 و G2 غلظت روی دانه بیشتری در مقایسه با ژنوتیپ های جدید داشتند. کمترین مقدار اسید فیتیک و نسبت مولی اسید فیتیک به روی و آهن در رقم G1 و بیشترین مقدار آنها در ژنوتیپ G4 حاصل شد. بیشترین عملکرد دانه در متر مربع (7/400 گرم)، غلظت روی دانه (4/33 میلی گرم در کیلوگرم) و غلطت آهن دانه (4/87 میلی گرم در کیلوگرم) به ترتیب با کاربرد برگی آهن + روی، روی و آهن حاصل شد. کاربرد روی در مقایسه با سایر سطوح محلول پاشی کمترین مقدار اسید فیتیک (5/6443 میلی گرم در کیلوگرم) و نسبت مولی اسید فیتیک به روی (1/19 میلی گرم در کیلوگرم) را داشت. بنابراین، کاربرد عنصر آهن و به خصوص روی در مناطق دیم با بهبود قابلیت فراهمی زیستی آهن و روی و عملکرد گندم می تواند نقش زیادی در فراهمی عناصر روی و آهن مورد نیاز داشته باشد.

    کلیدواژگان: اسید فیتیک، غلظت آهن، غلظت روی، محلول پاشی، نسبت مولی
  • علی استادی، عبدالله جوانمرد*، محمدرضا مرشدلو، سارا ملاعلی عباسیان صفحات 327-345

    به منظور بررسی اثر کودهای مختلف بر ویژگی های کمی و کیفی نعناع فلفلی (Mentha piperita L.)، آزمایشی به صورت اسپلیت پلات در زمان بر پایه طرح بلوک کامل تصادفی با هفت تیمار و سه تکرار و در دو چین در دانشکده کشاورزی دانشگاه مراغه در سال زراعی 1396 اجرا شد. عامل اصلی تیمارهای مختلف کودی شامل 100 درصد کود شیمیایی NPK، قارچ مایکوریزا (Glomus mosseae)، قارچ مایکوریزا+50 درصد کود شیمیایی، نانو کود (ماکرو+ میکرو)، 50 درصد نانو کود+50 درصد کود شیمیایی و نانو کود+ مایکوریزا و عدم مصرف کود (شاهد) و عامل فرعی زمان برداشت (چین اول و دوم) بودند. صفات مورد مطالعه شامل ارتفاع بوته، تعداد شاخه ی جانبی در بوته، شاخص کلروفیل، وزن خشک برگ، وزن خشک ساقه، وزن کل ماده خشک، درصد اسانس، عملکرد اسانس و صفات کیفی اسانس بودند. نتایج نشان دادند که صفات ارتفاع بوته، شاخص کلروفیل، وزن خشک برگ، وزن خشک ساقه، وزن کل ماده خشک و درصد اسانس تحت تاثیر معنی دار اثر متقابل نوع کود و چین در سطح احتمال یک درصد قرار گرفتند. علاوه بر این، اثر تیمارهای مختلف کوددهی و چین بر تعداد شاخه ی جانبی و عملکرد اسانس به ترتیب در سطح احتمال پنج و یک درصد معنی دار بودند. بیشترین عملکرد کل ماده خشک (6/382 گرم در مترمربع) به تیمار 100 درصد کود شیمیایی و به دنبال آن در تیمارهای 50 درصد کود شیمیایی+ مایکوریزا و 50 درصد کود شیمیایی+ 50 درصد نانو کود در چین دوم به دست آمد. از سوی دیگر، بیشترین (1/6 گرم در مترمربع) و کمترین (9/2 گرم در متر مربع) عملکرد اسانس نیز به ترتیب در تیمارهای 50 درصد کود شیمیایی+ مایکوریزا و شاهد به دست آمد. تجزیه شیمیایی اسانس نشان داد که در تمامی تیمارها منتول، منتون، 1،8 سینئول، نئو ایزومنتول، نئو منتول، منتوفوران و پی-منس-یک-این-9- ال جزء ترکیب های غالب اسانس بودند. بیشترین میزان منتول در تیمار نانو کود و در چین دوم به دست آمد. علاوه براین، در هر دو چین مونوترپن های هیدروکربنه جزء اصلی اسانس بودند. به طور کلی نتایج حاصل از این تحقیق نشان داد که کاربرد تلفیقی 50 درصد کود شیمیایی+ 50 درصد نانو کود و 50 درصد کود شیمیایی+ قارچ مایکوریزا می تواند در بهبود کمیت و کیفیت اسانس نعناع فلفلی و کاهش کودهای شیمیایی موثر باشد.

    کلیدواژگان: چین، کاربرد تلفیقی کود، کشاورزی پایدار، منتول، منتون
  • فرزانه ریگی، مهدی دهمرده*، عیسی خمری، رضا باقری صفحات 347-357

    استفاده موثر از کود نیتروژن و بهینه نمودن مدیریت مصرف آن در تولید گیاهان به خصوص در مناطق خشک و نیمه خشک از اهمیت به سزایی برخوردار می باشد، در این راستا به منظور ارزیابی تاثیر تقسیط کود نیتروژن و جهت های کاشت بر عملکرد و صفات فیتوشیمیایی چای ترش، آزمایشی به صورت اسپلیت پلات در قالب طرح بلوک های کامل تصادفی در سه تکرار در مزرعه تحقیقاتی دانشگاه زابل در سال زراعی 1396-1395 اجرا شد. تیمارهای آزمایش شامل جهت های کاشت در دو سطح شمالی-جنوبی و شرقی-غربی به عنوان عامل اصلی و تقسیط کود نیتروژن از منبع اوره در4 سطح یک سوم قبل از کاشت، یک سوم مرحله چهار برگی، یک سوم مرحله ساقه رفتن؛ یک دوم قبل از کاشت، یک دوم مرحله چهار برگی؛ یک دوم مرحله چهار برگی، یک دوم مرحله ساقه رفتن؛ یک سوم مرحله چهار برگی، یک سوم مرحله ساقه رفتن، یک سوم مرحله گلدهی به عنوان عامل فرعی بودند. نتایج نشان داد که اثر متقابل جهت کشت و تقسیط کود نیتروژن برای تمامی صفات اندازه گیری شده در آزمایش معنی دار (1 درصد) بود. بیشترین عملکرد کاسبرگ (784 کیلو گرم در هکتار) از جهت شمالی- جنوبی و استفاده از یک سوم کود نیتروژن در مرحله چهار برگی، یک سوم در مرحله ساقه رفتن و یک سوم در مرحله گلدهی و بیشترین مقدار آنتوسیانین کاسبرگ (98/2 میلی گرم در گرم کاسبرگ) با کاربرد یک سوم قبل از کاشت، یک سوم مرحله چهار برگی و یک سوم در مرحله ساقه رفتن از جهت کاشت شمالی- جنوبی حاصل شد. زمان بندی صحیح مصرف کود مهم تر از کل مقدار کود به کار رفته می باشد، تقسیط زمانی مصرف کود نیتروژن به صورت کاربرد یک سوم مرحله چهار برگی، یک سوم مرحله ساقه رفتن، یک سوم مرحله گلدهی، باعث افزایش ویژگی های کیفی و عملکردی چای ترش شد که در نتیجه می تواند کاهش هزینه های کودی و آلودگی محیط زیست را به دنبال داشته باشد.

    کلیدواژگان: گیاه دارویی، متابولیت ثانویه، عملکرد کاسبرگ
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  • Parviz Rezvani Pages 187-205
    Introduction

    Legumes are widely used in agricultural systems as green manure due to their ability to stabilize nitrogen in the soil, as well as providing conditions for beneficial soil microorganisms. Organic fertilizers such as vermicompost and manure have high capacity for water absorption and the maintenance of water and nutrients, high porosity, ventilation and appropriate drainage in the soil. Recently, bio-fertilizers have also been used to improve nutrient uptake and root development of plants along with chemical fertilizers. Lack of organic matter in most soils of Iran and its calcite properties will double the need to replace chemical fertilizers with organic fertilizers. Due to the lack of information on nutritional management of medicinal plants, and in order to increase soil fertility and the need to reduce the application of chemical fertilizers, this study was done to investigate the effect of different fertilizers on some soil chemical properties and the absorption of N and P elements in Birjand.

    Materials and Methods

    This research was carried out in two separate experiments during two growing years from 2014 to 2016 at the research farm of Birjand University with 3 replications. During the first experiment, the effect of four levels of green manures, including control, Eruca sativa, Vicia villosa, mix Eruca sativa + Vicia villosa and three levels of nitrogen (0, 50 and 100 kg.ha-1) on Purslane was studied. Furthermore, during the second experiment, the treatments were combination of four sources of nitrogen supply, including cow manure, vermicompost, chemical fertilizers (NPK) and control, as well as four types of biofertilizers, including Azotobacter and Azospirilum, Glomus intraradices, Thiobacillus with sulfur and control on Purslane was studied. The studied traits were included grain yield and soil chemical properties such as organic carbon, the percentage of nitrogen, absorbable phosphorus, pH, EC and nitrogen and phosphorus content of biomass. The percentage of nitrogen in plant tissue was measured by Kjeldahl method and the percentage of phosphorus was measured by Morphy and Riley method. Furthermore, the organic carbon in soil was determined by Walkley- Black method, total nitrogen and available phosphorus were measured using the Kjeldahl and Olsen methods, respectively. The soil acidity was determined on the saturated water through pH meter and electrical conductivity of the soil saturation extract was determined through EC meter. After collecting data, statistical analysis was performed using Minitab 17 software. LSD test was used at the 5% probability level to compare the averages.

    Results and Discussion

    The results showed that the application of green manure increased the organic carbon and nitrogen content of soil, the amount of phosphorus absorbed by soil and decreased soil pH. Among green manure treatments, Vicia villosa was superior to the others. Also, using nitrogen fertilizer increased grain yield and the amount of absorbed phosphorus, soil electrical conductivity and reduced soil pH. Among nitrogen supply sources, cow manure had the greatest impact on grain yield and soil chemical properties, but the role of biofertilizer application was limited to increasing the amount of available phosphorus in the soil. Therefore, the role of cow manure in improving the chemical status of soil was superior to the others. Due to the low soil organic matter in most arid and semi-arid regions of Iran, especially South Khorasan, it seems that proper usage of organic resources can improve soil conditions of these areas for the growth and yield of medicinal plants such as Purslane.

    Conclusions

    In this study, in order to reduce the use of chemical fertilizers and to absorb the maximum amount of nitrogen and phosphorus, the Purslane biomass was treated with mix Eruca sativa + Vicia villosa without using nitrogen fertilizer and combined treatment of cow manure and mycorrhiza.  The results recommended that combination of cow manure and mycorrhiza is suitable approach under Birjand condition.

    Keywords: Biosulfur, Cow manure, Mycorrhiza, Nitroxin, Vermicompost
  • Mohsen Jahan Pages 207-220
    Introduction

    The most fundamental agricultural obstacle particularly in arid and semi-arid regions is water shortage. To mitigate this problem, application of some soil amendments such as water super absorbent polymers (SAP) for increasing water-holding capacity in the soil has been under attention at commercial level in recent years.
    Despite numerous studies in Iran and the apparent positive and various functions have been mentioned for SAP and their advantageous in agriculture, there has not been a precise conclusion about these studies. On the other hand, variations in consumption rate, conditions and experimental treatments, makes an impossibility or hardiness to receive a conclusive result for the researchers studying one or few numbers of relevant articles.Meta-analysis is the statistical procedure for combining data from multiple studies. When the treatment effect (or effect size) is consistent from one study to the next, meta-analysis can be used to identify this common effect. When the effect varies from one study to the next, meta-analysis may be used to identify the reason for the variation. Decisions about the utility of an intervention or the validity of a hypothesis cannot be based on the results of a single study, because results typically vary from one study to the next. Rather, a mechanism is needed to synthesize data across studies (Rosenthal, 2001). Narrative reviews had been used for this purpose, but the narrative review is largely subjective (different experts can come to different conclusions) and becomes impossibly difficult when there are more than a few studies involved. Meta-analysis, by contrast, applies objective formulas (much as one would apply statistics to data within a single study), and can be used with any number of studies.
    Therefore, this study was conducted with the aim of doing meta-analysis on the results of conducted researches in Iran and to answer a general question that whether the application of SAP has been successful or not, and if yes, how much of SAP is recommended.

    Materials and Methods

    To conduct this research, articles were published during 2006-2016 with the subject of the effect of different rates of SAP on yield and yield components of crops (including cereals, legumes, medicinal and rangeland plants) were investigated. Amongst 32 articles were checked, 13 articles have enough data to conduct the meta-analysis for seed yield, dry matter yield and harvest index.

    Results and Discussion

    The result of meta-analysis showed that the mean consumption rate of SAP for cereals, legumes, medicinal and rangeland plants were 83, 322, 1031 and 210 kg ha-1, respectively, and with this consumption rate of SAP, the mean seed yield in cereals, medicinal plants and legumes increased by 13.2, 11.2 and 27.5% (equal to 1059, 345 and 452 kg ha-1), respectively, compared with control.
    Generally, the results showed that the effect of SAP on seed yield and dry matter was significant but was not significant for harvest index. The effect size of the application of different SAP rates on dry matter yield and at the whole levels was greater than its effect size on seed yield. The most effect size on seed yield was considered for the application of 100 kg ha-1 SAP and the application rates greater than 200 kg ha-1, unlike the dry matter yield, had no significant effect on seed yield.

    Conclusions

    According to the results, it seems that application of 100 kg ha-1 SAP is the most appropriate rate on seed yield and dry matter increment and economical aspects. Design and implementation of the researches focused on estimation and comparison of economic benefits about water consumption as the result of SAP application can justify the relatively high cost of this ecological input and provide the necessary ground for its widespread use by farmers and producers involved in agronomy and horticultural sections.

    Keywords: Cereals, Medicinal plants, Meta-analysis, Pulses
  • Vali Feiziasl Pages 221-240
    Introduction

    Nitrogen is the most important limiting factor, after water deficit for biomass production in natural ecosystems. Efficient use of nitrogen fertilizer is important to economical dryland wheat production and to the quality of ground and surface waters. Researchers have been looking for ways to increase the efficiency of N fertilizer use. Soil and in-season plant tissue testing for nitrogen status are a time consuming and expensive process. Chlorophyll concentration in a leaf is closely correlated with leaf N concentration so the Soil Plant Analysis Development (SPAD) chlorophyll meter is one of the most commonly used diagnostic tools to measure crop nitrogen status. The SPAD chlorophyll meter is a simple, portable, diagnostic and nondestructive light weight device used to estimate leaf chlorophyll content. Chlorophyll meter techniques provide a substantial saving in time and resources and offer a new strategy for synchronizing nitrogen application with actual crop demand. The objective of this study was to establish and analyze the relationships between measurements from a SPAD instrument and the leaf pigments, as extracted at different stages. The study also seeks to evaluate the utility of a chlorophyll meter to inform nitrogen fertilization rates of wheat (Triticum aestivum L.) genotypes in dryland condition.

    Materials and Methods

    This experiment was carried out in split split plot based on RCBD design with three replications. Treatment included: N application time (whole fertilization of N in fall, and its split fertilization as 2/3 in fall and 1/3 in spring), N rates (0, 30, 60 and 90 kg N ha-1) as urea and 7 genotypes (Azar2, Rasad, Ohadi, HN7/OROFEN//BGN8/3/SERI/4/.., SARA-BW-F6-06-85-86-29-1, TEVEE'S'//CROW/VEE'S' and DH-2049-3. A chlorophyll meter (SPAD-Hansatech Cl-01) was used to read leaf chlorophyll content (SPAD value) at tillering (GS22), shooting (29), stem elongation (GS32), flag leaf (GS39) and anthesis stages. Fresh plant leaf samples were collected from each plot for the estimation of chlorophyll a (Chla), chlorophyll b (Chlb), carotenoids (Ct), total chlorophyll (Chlt) and concentrations. The chlorophylls and carotenoids were determined by spectrophotometric analysis of chemically extracted pigments. To examine the relationship between pigments chlorophyll and SPAD values, 30 wheat leaves were sampled. Average Chla, Chlb, Chlt, carotenoids and SPAD values were computed, and linear regression analysis was performed by least-squares method with Excel.

    Results and Discussion

    The results showed a strong positive and statistically significant (p<0.01) relationship between SPAD values and total chlorophyll (R2 = 0.93), chlorophyll a (R2 = 0.95), chlorophyll b (R2 = 0.78) and carotenoids content (R2 = 0.79). We demonstrated that the SPAD readings and plant photosynthetic pigment content per-leaf are profoundly affected by nitrogen rate and timing of application. Nitrogen split application increased significantly (p<0.01) the SPAD values (8.3%), Chla (11.1%), Chlb (10.9%), Chlc (27%), Chlt (15%), (exception of carotenoids) and seed protein content (8.5%). Nitrogen application could affect significantly (p <0.01) all chlorophyll indices in plant. The ideal conditions for the chlorophyll indices in the plant were obtained using 72 kg N ha-1. Nitrogen requirement for maximum and optimum economical dryland wheat production is about 20 and 10 kg ha-1 less than nitrogen requirement for creation the ideal conditions for chlorophyll status and its components in dryland wheat. Using chlorophyll meter, chlorophyll a (16.6 mg g-1), chlorophyll b (5.9 mg g-1), chlorophyll c (0.077 mg g-1), total chlorophyll (23.9 mg g-1) and chlorophyll a per Chlorophyll b ratio (2.78), chlorophyll index (9.4) and chlorophyll relative index (1.0) were determined in economical optimum N rate (NRD = 0). Genotype1 was most suitable and Azar2 was the most inappropriate condition in terms of chlorophyll index and total chlorophyll ratio per carotenoids (optimum range 40-70) in the plant as a stress resistance index.

    Conclusions

    It can be concluded that, the actual chlorophyll content and its components can be estimated using chlorophyll meter (SPAD) in dryland wheat genotypes at different growth stages. Chlorophyll components and seed protein can be improved by nitrogen fertilizer application time and rates in dryland wheat.

    Keywords: Chlorophyll components, Economical optimum N rate, Biplot method, Growth stages, Water stress
  • Ali Asghari Pages 241-253
    Introduction

    Potato (Solanum tuberosum L.) is an important food and cash crop ranking fourth after maize, wheat and rice annual production in the world. It is a high biological value crop that gives an exceptionally high yield with more nutritious content per unit area per unit time than any other major crops. Thus, it can play a remarkable role in human diet as a supplement to other food crops such as wheat and rice. The main objective of the breeding program is to increase yield production. One of the major factors contributing to potato yield reduction is limited number of cultivars with wide range of adaptability and stability in tuber yield. Thus, evaluating genotypes across various environments for their stability of performance and range of adaptation is crucial and is an important component of the research activity of the national as well as regional research program.

    Materials and Methods

    20 potato hybrids along with five commercial cultivars (Savalan, Agria, Caesar, Luta and Satina) were evaluated in randomized complete block design with three replications at Agricultural and Natural Resources Research Station of Ardebil, Khorasan razavi, Karaj, Isfahan and Hamedan in 2016.  In this investigation each of the hybrids and control cultivars were planted in 2 rows of six meters. Row spacing of 75 cm and plant spacing of 25 cm was considered. There were 25 tubers in each row. Pest control was performed using 250 ml of Ha-1 Confidor. During growing period and after harvest the traits such as: plant height, day of tuberization, main stem number per plant, tuber number and weight per plant, total tuber yield and percentage of tuber dry matter were measured. Combined analysis of variances was done and comparison of means was done by LSD at five percent probability level. The linear correlation between traits was also calculated. In order to understand the inter-relationships of attributes and determine the variables with the highest correlation, factor analysis with Varimax rotation of factors was used. Grouping of the hybrids was performed based on the first three factors. In order to study the genetic diversity and heritability of traits, some genetic parameters of the traits in potato cultivars and hybrids were calculated. All analyses were carried out using the SAS9 and SPSS16 softwares.

    Results and Discussion

    Combined analysis of variance for traits showed significant differences among potato hybrids for all traits. The hybrids and environment interaction was significant for plant height, day of tuberization, tuber number and weight per plant, total tuber yield and tuber dry matter percent. Hybrids with number of 5, 9, 17 and 19 had the highest total tuber yield and the hybrid 20 and Satina cultivar had the lowest total tuber yield. The hybrids number 1, 3 and 20 had the highest amount of dry matter percentage compared to other hybrids suggesting that these hybrids are suitable for chips production. In factor analysis, three independent factors totally explained 75.744 percent of the variations. According to the results of factor analysis the following factors were nomenclature: the first factor as yield, the second factor as tuberization and third factor as plant. The weight per plant and tuber number per plant had the highest heritability, genetic gain, genotypic and phenotypic coefficient of variation. These traits can be improved through selection in breeding programs.

    Conclusions

    In general, the results of the mean comparison and grouping of hybrids based on the first three factors showed that hybrids 5, 17 and 19 were better than the other hybrids. Hybrids 1, 3 and 20 with the highest percentage of dry matter are recommended for processing as chips. The weight per plant and the number of tubers per plant had the highest genetic gain and heritability rates, and these two traits could be improved through selection in breeding programs.

    Keywords: Genetic advance, Genetic parameters, Heritability, Hybrid, Potato, Yield
  • Mostafa Oveysi Pages 255-264
    Introduction

    Scrophularia striata is an originally Iranian wild perennial plant. This plant has many medicinal properties including treatment of some diseases like cold, digestive disorders, inflammation and infection. Although S. striata has been reported from various regions of the country with different climatic conditions, however there is no information about phenological growth, suitable time and seedbed of S. striata. There are variety of environmental factors that affect phenology growth. Among them temperature is considered as the most effective one. To generalize prediction of phenological growth in different locations, standard measurement is required. Growth degree day (GDD) or thermal time can be a consistent predictor of phenology development in contrasting climates. Determining required thermal time for plant phenological development would provide information for decision making on the time of management practices including planting date, timely irrigation and efficient pest and weed management. To the best of our knowledge there is no information about plant establishment, growth and phenological stages of S. striata. Because of its high demands for medicinal products, information about the S. striata cultivation is necessary. Therefore the objective of this study was to determining the effect of planting time and seedbed on phenological growth.

    Materials and Methods

    Field experiment was conducted in experimental farm of agricultural and natural resources college, university of Tehran, Karaj during 2016-2017. Seeds were preconditioned at temperature of 3ºc for one week to break dormancy. For seedling establishment, seeds were transferred to the greenhouse and cultivated in three different seedbeds. Seedlings were transferred to the farm at stages of four to six leaves. The experiment was a split plot with three replications. Planting dates comprised Early June (D1), September (D2), October (D3) and November (D4) of 2016 and Early March (D5) of 2017 were the main plots and seed beds of peat moss, peat moss+ perlite (1:1) and coco peat+ peat moss+ perlite (2:1:1) were the sub plots. Growth Degree Days (GDD) for phenological stages of S.striata including first and second node, flowering, capsule formation, seed formation and maturity were calculated. Data were subjected to ANOVA using SAS 9.1, and standard error of means was calculated.

    Results and Discussion

    Results showed significant main effects and interactions between seed bed and planting date at 1% probability level on phenological growth of S. striata. Peat moss seed bed with June planting had lowest GDD to first node (39.5 GDD), second node (50.1 GDD), flowering (307.4 GDD), capsule formation (610.8 GDD), seed formation (697.8 GDD) and maturity (1242.0 GDD). With delay in planting time to September, October and November, GDD requirements for phenological growth increased. Between our planting dates, June planting time was the most suitable time for planting. Changes in temperature, day light and precipitation are significant in successful plant establishment and growth. Our results showed that there is a critical time for planting S. striata in farm. Very early planting like March planting time was not good and plants did not enter the reproductive stage. Plants of June planting time were entered flowering stage on April 15 in the next year. With delay in planting time to November, plants entered flowering stage on May 10 in the next year. High organic matters percentage and capacity of cation exchange provides increasing potential for water absorption and keeping nourishing elements and water for a longer time. This causes improved conditions for root growth. In addition, vermicompost and peat moss includes regulator hormones such as humic acid that benefits early growth of plant.

    Conclusions

    To conclude, 1) peat moss was recognized as a successful bed for initial growing of S. striata. To the best of our knowledge, no practical recommendation was formerly provided on the subject. 2) June planting time was determine as the best time for plant establishment that led to acceleration in flowering time and more seed production.

    Keywords: Domestication, Endemic plant, GDD
  • Siavash Bardehji Pages 265-273
    Introduction

    Medicinal Pumpkin (Cucurbit apepo convar. pepo var. styriaca) is a valuable medicinal plant in pharmaceutical industry. Iran has a semi-arid climate and located in areas suffer from water stress which can be considered as the biggest problem in crop production. Therefore, to achieve the highest yield of products in times of stress, the crop should be under full irrigation or proper management to make better use of the water in critical phases of crop growth. One of these managements is to reduce soil evaporation by using mulch .Mulching, reduces the amount of sunlight and preventing water evaporation effects on microclimate and provides a favorable environment for plant growth and development. The water resources in the country are limited and it needs to be efficiently used. Then an experiment was carried out aiming to investigate the effects of different levels of irrigation and plastic mulch on yield and yield components of medicinal pumpkins in weather conditions of Mashhad.

    Materials and Methods

    This study was conducted in split plot design based on randomized complete blocks with three replications at the Agricultural Research Station, Ferdowsi University of Mashhad during growing season of 2014-2015.The main plots were irrigation including 50, 75 and 100% crop water requirement and two black plastic mulch surface (presence and absence of mulch) arranged as subplot. The distance between rows of 200 cm and distance between two plants was 30 cm. There were three rows of cultivars in each plot with a density of 34.3 plants.m-2. Based on soil test results and fertilizer requirements, 180 kg.ha-1 of urea and 100 kg kg.ha-1 of P2O5 were given to the land. The planting was carried out two weeks after irrigation and according to the air temperature. Irrigation of plots was done every seven days by polyethylene pipes and the volume of water entering the plots was measured. Yield and its components were measured at the end of growing season.

    Results and Discussion

    The results showed that irrigation reduction resulted in a significant (p<0.01) change in all studied traits. For example, 50 percent reduction in irrigation reduced fruit yield by 68 percent compared to control. Reduction in fruit yield under water stress conditions can be related to a reduction in flower production in plant. Mulch had also significant effect (p<0.01) on total dry weight, leaf area index, fruit yield, seed yield, harvest index, and also on 1000-seed weight (p<0.05). Use of mulch increased fruit and seed yield and harvest index by 38.4%, 38.4% and 30.6% compared to the lack of mulch, respectively through reduced soil evaporation and increases available water of plant. Irrigation× mulch affected significantly (p<0.01) on total dry weight, leaf area index, harvest index fruit and seed yield, and seed weight per plant. Plant yield reduction under drought stress could be could be attributed to decrease in plant photosynthesis, leaves aging, and decrease in gas exchange due to stomatal closure. In general, irrigation of 75% of the plant's water requirement and the use of plastic mulch is the best condition for planting Medicinal Pumpkin. Because it greatly saves water consumption and also had the highest rate of production.

    Conclusions

    The results of this study indicated that irrigation based on plant need can play an important role in increasing yield and yield components of pumpkin plant in drought conditions Also, the plastic mulch by preventing water loss, increases the amount of water available to the plant and reduces the effect of stress and improves plant yield.
    Acknowledgement: This study has been funded by the University of Mashhad faculty of Agriculture and we would like to thank you in this regard.

    Keywords: Deficit irrigation, Fruit yield, Mulch, Seed weight, Seed yield
  • Mokhtar Ghobadi Pages 275-289
    Introduction

    Grain yield depends on genetic potential of plant. Environmental factors play an important role to achieve this potential. Inappropriate management of irrigation and nitrogen are main factors to reduce the maize yield. Better control of environmental effects in breeding programs can be achieved through indirect selection for traits that in addition to high heritability have a good correlation with yield and be less affected by environmental changes. This study was conducted to investigate the correlation and cause and effect relationships between some traits with yield of maize in different irrigation and nitrogen conditions.

    Materials and Methods

    This experiment was done during 2014-15 at Razi University, Kermanshah, Iran. The experiment was conducted as split plot. Main plot factor was four irrigation levels included supplying 120, 100, 80 and 60% water requirement (I120%, I100%, I80% and I60%, respectively), and sub-plot factor included four nitrogen levels 40, 70, 100 and 140% (N40%, N70%, N100% and N140%, respectively) of recommended amount based on the soil test. During growth period, the time of occurrence of growth stages were recorded and at harvest stage, yield, its components, ear size and grain dimensions were measured. Pearson correlation coefficients and stepwise regression analysis were determined using SPSS software. Direct and indirect effects of traits on grain yield were determined by path analysis using PATH2 software.

    Results and Discussion

    Results of correlation analysis in all irrigation conditions showed that the higher total dry weight and less interval of anthesis until silking are desirable. In addition, selection for 100 grain weight, number of days from planting until physiological maturity and harvest index in I120%, I100% and I80% would improve grain yield. Under I60%, negative selection for grain depth and number rows per ear can improve grain yield. Positive correlation between ear size, yield components, plant height, grain length, number of days from planting until physiological maturity and harvest index with grain yield and negative selection for cob percent, grain thickness and interval of anthesis until silking in all nitrogen levels would improve grain yield. Results of regression analysis under I120%, I100% and I80% showed that 100 grain weight explained a high percentage of grain yield changes. Under I60%, grain depth had the highest contribution to explaining grain yield changes. Under N70%, N100% and N140%, harvest index and total dry weight that explain a significant percentage of total grain yield changes. In N40%, number of grain per row will be effective on grain yield. In I120% and I100%, 100 grain weight and number grains per row, in addition to high direct effects on grain yield, had a significant indirect effect on grain yield through each other. In I80%direct effect of 100 grain weight and indirect effect of plant height through it on grain yield were observed. In I60% selection for grain depth, interval of anthesis until silking and days from planting until anthesis would be more appropriate. Due to negative correlation between grain number per row with grain yield and positive direct effect of it in I60%, the indirect effects of grain number per row should be considered. Regarding nitrogen levels, in N40%, grain number per row had a direct effect on grain yield. In N70%, N100% and N140%, total dry weight and harvest index in addition to relatively high direct effects on grain yield, had an indirect effect on each other.

    Conclusions

    In all environmental conditions, traits entered to regression models explained more than 95% of grain yield changes. Based on the results of path analysis, under I120% and I100% conditions, 100 grain weight and number of grains per row, in I80%, 100 grain weight and plant height, under severe deficit irrigation, grain depth and interval of anthesis until silking due to considerable direct and indirect effects on yield introduced as proper indices to improve grain yield. At all nitrogen levels, selection based on total dry weight and harvest index will be helpful. Number of grains per row and 100 grain weight should also be considered due to high indirect effects on grain yield at some nitrogen levels.

    Keywords: Grain yield, Independent variable, Stepwise regression, Water deficit
  • Abolfazl Derakhshan Pages 291-303
    Introduction

    Crop biomass accumulation is directly related to the amount of photosynthetically active intercepted radiation by the canopy during the crop’s cycle. The slope of this relationship represents the radiation use efficiency (RUE), defined as crop biomass produced per unit of total solar or photosynthetically active intercepted radiation (IPAR). Therefore, above-ground biomass (g m−2) can be expressed as a product of the cumulative IPAR (MJ m−2) during the crop cycle and RUE (g MJ−1). The amount of IPAR depends on the length of the crop cycle over which radiation is accumulated, the fraction of intercepted radiation (FIR) by the canopy each day and the total incident solar radiation. The length of crop cycle is affected by the genotype and/or environmental factors mainly temperature and photoperiod. Indeed, soil constraints such as nutritional deficiencies have shown minor impacts on the crop cycle. FIR depends on the leaf area index (LAI) and the canopy light extinction coefficient (k). Several studies on different crops have shown that IPAR is negatively affected by nitrogen (N) deficiency. RUE is affected by the crop species, environmental conditions and also by management factors such as crop nutritional status. Over the past few decades, one of the aspects of improving crop productivity has been increasing N fertilizer utilization. Nitrogen application is one of the key inputs for crop production that determines the potential of total crops dry matter production through its effect on IPAR, RUE, and/or both. The aim of the present study was to comparatively evaluate in two rapeseed cultivars their responses on IPAR, RUE and related traits under different N availabilities at field conditions.

    Materials and Methods

    In this study, the effects of N utilization on IPAR and RUE of two spring rapeseed cultivars (Hyola 401 and Dalgan) were investigated. Field experiment was conducted as a split plot in a randomized complete block design with three replications at Agricultural Sciences and Natural Resources University of Khuzestan. N consumption in seven levels of 0, 50, 100, 150, 200, 250 and 300 kg ha-1 was considered as the main factor and the type of rapeseed cultivar in two levels as the sub-factor.

    Results and Discussion

    The results showed that the response of the above-ground biomass to N supply in both of the studied rapeseed cultivars was related to the change in both IPAR and RUE. The total accumulated IPAR during the growing season under of consumption of 200 kg N ha-1 was about 27 and 35% higher than those of the control treatments in the cultivars Hyola 401 and Dalgan, respectively. In both rapeseed cultivars, IPAR was strongly dependent on LAI and LAD. This means that N utilization with increasing LAI and LAD resulted in an increase in IPAR. Reduction of LAI in response to N deficiency can be explained by (1) changing the phyllochron, (2) decreasing leaf blade area, and (3) the higher rate of loss of old leaves. Utilization of N had no effect on the light extinction coefficient (K) of crop canopy, and this coefficient was estimated to be 0.65 (± 0.02) in the cultivar Hyola 401 and 0.73 (± 0.02) in the cultivar Dalgan. Depending on N level, the above-ground biomass varied from 932 to 2192 g m-2 in the cultivar Hyola 401 and between 853 and 1811 g m-2 in the cultivar Dalgan. Depending on the availability of N, the RUE varied between 2.02 (control treatment) and 3.25 g MJ-1 (200 kg N ha-1) for the cultivar Dalgan and between 1.86 (control treatment) and 3.62 g MJ-1 (300 kg N ha-1) for the cultivar Hyola 401. Reducing RUE in N-limit treatments may be due to reduced leaves nitrogen content, which reduces their photosynthetic capacity.

    Conclusions

    The results of this study showed that the above-ground biomass production by two rapeseed cultivars was related to differences in their growth rates in response to the applying different amounts of N. The physiological traits that explained above-ground biomass responses of both cultivars were the cumulative intercepted radiation during the crop cycle and radiations use efficiency. In both rapeseed cultivars, the K coefficient was not affected by N utilization, which indicates that IPAR responses were the result of changes in LAI and LAD during the crop cycle affecting the fraction of intercepted radiation by the crop.

    Keywords: Fraction of intercepted radiation, Light extinction coefficient, CGR, LAD, LAI
  • Abdollah Sajedi Pages 305-316
    Introduction

    Safflower (Carthamus tinctorius L.) is one of the oldest seed oil crops cultivated and is known for drought tolerance due to partially xerophytes nature, as well as deep and extensive root system making efficient use of reserved soil moisture. Seed germination depends on environmental factors especially temperature and humidity. Seed priming is one of the current methods for increasing the rate, percentage, germination uniformity and seed emergence under environmental undesirable. Seed priming with plant growth regulators especially salicylic acid improved quality and seed yield. Salicylic acid acts as anti-transpiration and inhibited from open stomata. Salicylic acid plays an important role in plant consistency to osmotic stress, high salinity, oxidative stress, high temperature, and freezing stress. Biochar is created by pyrolysis of natural materials. Biochar increased the soil porosity and therefore improved water retention capacity in soil. It was reported that application of 2.5, 5, 10, 20, 30 and 40 t/ha biochar increased canola yield by 16.21, 21.15, 27.99, 24.60, 33.20 and 36.02% compared with control, respectively.

    Materials and Methods

    To evaluate the effect of biochar and seed priming with salicylic acid and water along with foliar application on yield, yield components and oil percentage of safflower in rain fed condition, an experiment was performed as split- split plot based on randomized complete blocks design in three replications, at the Research Station of Islamic Azad University, Arak Branch, Iran, during 2016-2017. Experiment factors were included biochar in three levels of 0, 5 and 10 t/ha; seed priming in three levels of zero priming, priming with water distillation and seed priming with 0.5mM salicylic acid and foliar application in two levels of foliar application with water and 1 mM salicylic acid. Seeds primed for 12 hr at distilled water and salicylic acid solutions then dried at shade. Biochar was applied at 15 cm depth and under the seed, before sowing. Each experimental plot included 30cm spacing rows with 15cm spacing between plants in rows. The safflower cultivar was ‘Esfahan native’. The seeds were sown at 3-4 cm depth in middle of March 2016. The assay for agronomic traits, yield and yield components was determined from 10 plants.  Data were subjected to analysis of variance using SAS. The Duncan's multiple range test at 5% the confidence level were used to compare means.

    Results and Discussion

    Results showed that the application of 5 and 10 t/ha biochar increased seedling emergence percentage by 23.7 and 40.4% compared to control. Increasing of seedling emergence percentage by seed priming can be due to repair of deteriorated seed, improve DNA representation and decrease of germination base temperature. Application of 5 t/ha biochar increased the number of heads per plant by 15.9% compared to control. Seed priming with distilled water increased the number of heads per plant by 7% compared to control. Seed priming with water distilled along with the foliar application by water increased number of fertile heads per plant by 13.9 percentages as compared with control. The highest number of seeds per head was recorded by the application of 5 t/ha biochar and seed priming with water distillate. Application of 10 t/ha biochar combined with foliar application of salicylic acid, 5 t/ha biochar combined  with foliar application of water and application of 10 t/ha biochar combined with foliar application of water increased the number of seeds per head by 13.4, 9.8 and 2.9 compared with control, respectively. The maximum of the 100-grain weight obtained from the application of 10 t/ha biochar combined with seed priming by distilled water that increased the 100-grain weight by 17.4% as compared with control. Application of 5 t/ha biochar along with seed priming with water or salicylic acid increased seed yield by 22.4  and 8.7% compared to control, respectively. Application of 5 t/ha biochar  combined with a spray of water or 10 t/ha biochar along with the foliar application of salicylic acid increased grain yield by 18.7 and 21.9% compared with control, respectively. Increasing grain yield in rice and sorghum by biochar was reported. The highest oil percentage was obtained from the application of 5 t/ha biochar and seed priming with water along with the foliar application of salicylic acid.

    Conclusions

    In general, it is concluded that seed priming by water or salicylic acid along with the application of 5 t/ha biochar combined with foliar application of water  in two stages in the duration of growth improved agronomic traits and grain yield of safflower in Rain-fed Condition.

    Keywords: Dryland farming, Oil percentage, Oil seed, Seed pre-treatment, Yield components
  • Manochehr Shiri Pages 317-326
    Introduction

    Wheat is one of the most important foods for the people in the world. For many Central Asia and Middle Eastern nations, wheat provides ≈50% of the daily energy consumption and the proportion can exceed 70% in rural areas. The production of high-yielding modern cultivars may provide the amount of energy needed by humans, but these cultivars, due to the low concentration of micronutrients such as iron (Fe) and zinc (Zn), are usually deficient and cause health problems. This shortage is intensified in dryland areas due to dryness, alkalinity, and so on. Two-thirds of the total area under wheat cultivation in Iran belongs to rainfed wheat. Declines in the concentration of micronutrients such as Fe and Zn in cereal grain which are often important sources of micronutrients for humans cause several diseases. Agronomic fortification (e.g., fertilizer application) is imperative and necessary for improving micronutrient concentrations in grains in a short period. Phytic acid has a high potential for binding Zn and Fe, making them less bioavailable for humans. If the amount of phytic acid in the wheat grain is high, the absorption of small elements in the intestine decreases. The use of micronutrient fertilizers, such as zinc reduces the amount of phytic acid and enhance grain zinc concentration. Therefore, the purpose of this research was to investigate the role of zinc and iron fertilizers on the performance and quality of modern and local cultivars of bread wheat.

    Materials and Methods

    To investigate the role of iron and zinc Nano-chelate fertilizers on the improvement of grain yield and elemental composition of bread wheat cultivars, a factorial experiment based on randomized complete block design with three replications arranged in Moghan Agricultural and Natural Resources Research Center, 2015-2016. The first factor was control and spraying with iron, zinc, and iron + zinc. The cultivars included Aftab (G1), Karim (G2) and two new genotypes (G3 and G4). Foliar application of Khazra iron and zinc Nano-chelate fertilizers was carried out at tillering, early of heading and milky stages with a ratio of 2 and 1.5 per thousand, respectively. Iron, zinc, and iron + zinc Nano fertilizers at the rate of 2 kg ha-1, 1.5 kg ha-1 and 2 + 1.5 kg ha-1 were sprayed at every stage. Ammonium phosphate and urea fertilizers at a rate of 50 kg ha-1 from each one of them were applied before planting. Measurement of Fe and Zn elements was carried out at wavelengths of 233.28 and 2333 nm, respectively with the use of the atomic absorption device Shimadzu, AA-6300. Measured traits included a number of spikelets per spike, number of grains per spike, number of seeds per spike, and 1000 grain weight per the main spike, grain yield m2, zinc concentration, iron concentration, phytic acid, and phytic acid molar ratio to zinc and iron.

    Results and Discussion

    The results showed that cultivar G1, G2, and G3 produced significantly higher seed yield than G1. This was mainly due to an increase in spikelet number, the number of seeds per spikelet, and/or both. The G1 and G2 cultivars had a higher concentration of zinc in comparison with the new genotypes. Cultivar G1 had the highest Phytic acid and phytic acid to zinc and iron molar ratio, and genotype G4 had the lowest values. Maximum grain yield, Zn and Fe concentrations were obtained at the foliar application of Fe + Zn, Zn, and Fe, respectively. Zinc application had the lowest amounts of phytic acid and phytic acid to Zn molar ratio in comparison with the other spraying levels.

    Conclusions

    As a result, the foliar application of iron and especially zinc in dryland farms, by improving the bioavailability of iron and zinc and increasing wheat yield, can play a significant role in providing daily energy intake and reducing health risks.

    Keywords: Iron concentration, Molar ratio, Phytic acid, Spraying, Zinc concentration
  • Abdollah Javanmard Pages 327-345
    Introduction

         In order to protect biodiversity, especially medicinal herb, and crude herbal drugs from the wild origin, Biological Diversity Act (2002) and Rule (2004) were enforced which compelled the herbal industries and medicinal plant growers for conventional cultivation of medicinal herbs. However, intensive cultivation of these medicinal herbs and herbal drugs to meet the global demand has led to aggravated use of chemical fertilizers and pesticides and consequently questioning their safety and integrity. Moreover, total fertilizer nutrient (N+P2O5+K2O) consumption was estimated at 170.7 and 175.7 million tons in 2010 and 2011, respectively which estimated consumption of N, P, and K fertilizers is expected to increase from current consumption levels by 172%, 175%, and 150%, respectively by 2050. Excessive using of chemical fertilizers caused serious environmental issues globally such as reduction of plant diversity, instability of economic yield, an increase of pest and disease damages, intensification of soil erosion. These increasing concerns regarding the negative impacts of these systems on the environment and human health suggest that more effort is needed to develop sustainable agricultural systems with higher productivity and improved efficiency. Application of nano-fertilizers and biofertilizers such as arbuscular mycorrhizal fungi (AM) is regarded as one of the promising approaches to increasing crop productivity. Nano-materials (NMs) are defined as materials that with at least one dimension less than 100 which can improve one or more nutrients absorption for plants and enhance their growth and yields. The AM fungi are a fundamental group of soil micro-organisms, symbiotically associated with nearly 80% of plant species.
    Peppermint (Mentha piperita L.), which is a hybrid between Mentha spicata and Mentha Aquatica belonging to a family, Lamiaceae, is one of the most important essential oil-bearing plants. The objective of this experiment was an evaluation of the quantity and quality traits of peppermint under the integrated application of chemical and nano-fertilizers and arbuscular mycorrhizal fungi.

    Materials and Methods

    In order to investigate the effects of different fertilizers on the quantity and quality of peppermint at the first and second cuttings, a field experiment study was carried out as split-plot in time based on a randomized complete block design (RCBD) with seven treatments and three replications and two cutting times at the faculty of Agriculture, University of Maragheh, Iran, in 2017. The main factor was different fertilizer treatments included no fertilizer (control), chemical fertilizer (CF), arbuscular mycorrhiza fungi (AMF) (Glomus mussels), 50% CF+ AMF, Nano-fertilizers (NF), 50% NF+ 50% CF, NF+ AMF and the sub-factor was cutting time (first and second cutting). In AM fungi treatments, 80 g of the soil containing mycorrhizal fungi hyphae and the remains of the root and spores (1000 g spore.10-1 g soil) was added to soil in planting times. Also, Nitrogen Nano-fertilizer used with 2 ml/L concentration. Moreover, phosphorus, potassium, iron and zinc Nano-fertilizers applied with 1 g.L-1 concentration. Furthermore, manganese Nano-fertilizer used in 0.5 g/L concentration. Additionally, the foliar application of Nano-fertilizers was carried out in two-stage (One month after the cultivation and one month after first cutting).

    Results and Discussion

    The results demonstrated that the highest total dry matter yield (382.6 g.m-2) was achieved under 100% CF followed by 50% CF+ AMF and 50% NF+ 50% CF treatments, respectively. On the other hand, the highest (6.1 g.m-2) and lowest (2.9 g.m-2) essential oil yield were obtained under 50% CF+ AMF and control, respectively. Chemical analysis of the essential oil demonstrated that in all treatments, menthol, menthone, 1, 8 cineole, neo-iso menthol, neo-menthol, Menthofuran, and p-Menth-1-en-9-ol were the main dominant components. The highest amount of menthol was obtained in nano-fertilizer treatment and at the second cutting. Furthermore, monoterpene hydrocarbons were the major fraction of the essential oil in both harvests.

    Conclusions

    Based on the results, integrative application of 50% CF+ AMF and 50% CF+ 50% NF had a higher significant impact on the morphological traits compared with other treatments. The highest dry matter yield was achieved in the second cutting with the application of CF that was not significantly impacted with 50% CF+ AMF and 50% CF+ 50% NF treatments. Also, the highest essential oil content was obtained the integrative application of 50% CF+ 50% NF that was 7.1% higher than CF in the first cutting. In addition, the essential oil yield productivity increased 198% with application of 50% CF+ AMF and 50% CF+ 50% NF compared with control. Based on the essential oil compounds, the highest (46.31%) and the lowest (26.73%) content of menthol was recorded in the second cutting fertilized with NF and first cutting fertilized with CF. Generally, based on the obtained results, integrative application of AMF and NF with 50% CF increased the quality and quantity productivity of peppermint compared with 100% CF.

    Keywords: Cutting, Integrated fertilizers application, Menthol, Menthone, Sustainable agriculture
  • Mahdi Dahmardeh Pages 347-357
    Introduction

    Roselle (Hibiscus sabdariffa L.) is one of the important medicinal and industrial herbs in tropical and semi-tropical regions, which, in addition to multiple drugs use. The quality and quantity of the active ingredient of medicinal plants are affected by the applied crop. Light is recognized as one of the most important factors in competition in ecosystems. Nitrogen is the first element that has a shortage in arid and semi-arid areas due to lack of soil organic matter.  Since the use of maximum environmental capacity and the most suitable growing conditions in order to increase the quantitative and qualitative yield and maximize productivity, it is important for agricultural management. The aim of this research was to investigate different cultivars to determine the most suitable culture for planting, optimum use of chemical fertilizers and determine their best time for increasing the quantitative and qualitative yield under Zabol climatic conditions.

    Materials and Methods

    A split-plot experiment was conducted in a randomized complete block design with three replications at the Research Institute of Zabol University during the growing season of 2016-2017. Treatments experiment included two levels of planting directions (North-South, East-West) as the main plot and the split of nitrogen fertilizer from the source of urea in four levels (1/3 per planting, 1/3 four-leaf stage, 1/3 stem elongation; 1/2 post planting, 1/2 four-leaf stage; 1/2 four-leaf stage, 1/2 stem elongation; 1/3 four-leaf stage, 1/3 stem elongation, 1/3 flowering stage) as a sub-plot. Ecological parameters such as light, at the end of the flowering stage, Biochemical characteristics and yield were measured at the end of the growing season. Analysis of variance done by software SAS ver. 9.1 and comparison of means treatment by Duncan test at 0.05 level. 

    Results and Discussion

    The results of the analysis of variance showed that the interaction of planting directions and nitrogen fertilizer split exception for the traits vitamin c, for all traits measured is very significant. Based on the results of the comparison of means treatments showed that all traits had the highest amount in the planting directions (north-south). The highest dry sepal yield (784 kg.ha-1) and anthocyanin (2.98 mg.g-1) were obtained from north-south planting. The correct timing of fertilizer use is more important than the total amount of fertilizer used. Split timing of nitrogen application for the use of 1/3 four-leaf stage, 1/3 stem elongation stage, 1/3 flowering stage, increased the qualitative and functional characteristics of roselle. The effect of Interaction planting direction and splitting of fertilizer was significant on carotenoid, the highest of carotenoid was obtained at north-south with an application nitrogen fertilizer at 1/3 four-leaf stage, 1/3 stem elongation, 1/3 Flowering stage (0.36 mg.g-1).  

    Conclusions

    In general, the results of this research showed that for planting directions North-South, using better ecological factors such as light, temperature, nutrients, and followed by application of nitrogen fertilizer, split in four-leaf stage, stem elongation, flowering Improvement of growth, an increase of yield and quality of sepal in the Roselle plant. Since nitrogen is one of the most effective elements in increasing the quality yield of medicinal plants, optimum management of nitrogen as a split application at times that are more adapted to the critical stages of the plant's needs. It is recommended to achieve sustainable agriculture and environmental protection.

    Keywords: Medicinal plant, Secondary metabolite, Sepal yield