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مطالعات حفاظت گیاهان - سال سی و یکم شماره 4 (زمستان 1396)

فصلنامه مطالعات حفاظت گیاهان
سال سی و یکم شماره 4 (زمستان 1396)

  • تاریخ انتشار: 1396/12/08
  • تعداد عناوین: 16
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  • علمی - پژوهشی
  • عباس عباسیان، محمدحسن راشد محصل، احمد نظامی، ابراهیم ایزدی دربندی صفحات 548-557
    علف های هرز از عوامل عمده کاهش ارزش کمی و کیفی نخود می باشند. به همین منظور آزمایشی جهت کنترل علف های هرز نخود به صورت بلوک های نواری5 بر مبنای طرح بلوک کامل تصادفی با سه تکرار انجام شد. فاکتورهای مورد بررسی در آزمایش شامل سیستم خاک ورزی در سه سطح (خاک ورزی در شب، روز و شخم در روز با محافظ نوری) به عنوان عامل اصلی و مقادیر علف کش تریفلورالین (480، 960 و 1440 گرم ماده موثره در هکتار) و ایمازتاپیر (50، 100 و 150 گرم ماده موثره در هکتار) و شاهد عاری از علف های هرز در تمام فصل رشد و شاهد بدون وجین و کاربرد علف-کش عامل فرعی بود. تراکم علف های هرز در تیمار عملیات خاک ورزی در روز با محافظ نوری نسبت به عملیات خاک ورزی در روز و شب بیشتر بوده و بین عملیات خاک ورزی در روز و عملیات خاک ورزی در شب نیز اختلاف معنی داری (P≤ 0.05) وجود نداشت. زیست توده علف های هرز درتیمار مقادیر کاهش یافته علف کش ها در انتهای فصل رشد تفاوت معنی داری با یکدیگر نداشتند. کمترین عملکرد دانه مربوط به تیمار شاهد بدون کنترل (1151 کیلوگرم در هکتار) و بیشترین آن مربوط به تیمار شاهد کنترل (1977 کیلوگرم در هکتار) بود و همچنین در بین مقادیر کاربرد این علف کش ها از لحاظ آماری اختلاف معنی داری از این لحاظ وجود نداشت. نتایج نشان داد مقادیر کاهش یافته علف کش ها می تواند موجب کنترل کافی علف های هرز شوند بدون اینکه تاثیر منفی بر عملکرد نخود داشته باشند.
    کلیدواژگان: پرسویت، ترفلان، شخم شب
  • سبحان محضری محمد علی باغستانی صفحات 558-567
    به منظور بررسی تاثیر مدیریت شیمیایی بر جمعیت علف های هرز و خصوصیات زراعی گیاه سیر، آزمایشی در قالب طرح بلوک های کامل تصادفی با سه تکرار در سال 1391- 1392 انجام پذیرفت. تیمارهای مورد بررسی شامل کاربرد تری فلورالین 5/1، 2 و 5/2 لیتر در هکتار، اکسی فلورفن 5/1، 2 و 5/2 لیتر در هکتار در یک مرحله، اکسی فلورفن 5/1 لیتر در هکتار در دو مرحله، شاهد تداخل علف های هرز (تعداد دو تکرار در هر بلوک) و شاهد عاری از علف هرز بود. نتایج نشان داد که مصرف علف کش های مختلف تاثیر معنی دار بر تراکم و زیست توده علف های هرز مزارع سیر داشت. بالاترین درصد کنترل زیست توده علف های هرز در تیمارهای مصرف 5/1، 2، 5/2 لیتر اکسی فلورفن، تقسیط 5/1 لیتر اکسی فلورفن در دو مرحله و وجین دستی به ترتیب با %3/96، %09/99، %64/99، %52/97 و %83/99 حاصل شد. مصرف 2 و 5/2 لیتر اکسی فلورفن موجب خسارت متوسط و کمی پایدار بر گیاه سیر شد. مصرف مقادیر مختلف علف کش های مختلف سبب تاثیر معنی دار بر ارتفاع بوته، تعداد حبه در سوخ3، وزن 100 حبه، عملکرد اقتصادی و بیولوژیک و شاخص برداشت سیر شد. کمترین عملکرد اقتصادی در تیمار عدم کنترل علف های هرز (g.m-2 540) و بیشترین آن تحت سه تیمار مصرف 5/1 لیتر اکسی فلورفن (g.m-2 67/1661)، وجین دستی (g.m-2 67/1686) و تقسیط 5/1 لیتر اکسی فلورفن در دو مرحله (g.m-2 1670) توزین شد. نهایتا تیمار مصرف 5/1 لیتر اکسی فلورفن در 3 الی 4 برگی علف های هرز به عنوان مناسب ترین تیمار معرفی شد.
    کلیدواژگان: اکسی فلورفن، تری فلورالین، زیست توده، سیر، علف هرز، عملکرد اقتصادی
  • افروز حسنی بوساری، جواد ترکمن، مهرداد قدس خواه دریایی صفحات 568-575
    هدف از این پژوهش مقایسه اندازه قطر آوندهای چوبی بهاره و تابستانه و برخی خصوصیات بافت شناسی مرتبط با آن در گونه های سالم و بیمار شاه بلوط بود. در این مطالعه به منظور بررسی تاثیر قارچ Cryphonectria parasitica نمونه ها از چوب و پوست درختان بیمار و سالم در سه طبقه قطری (قطور، متوسط و کم قطر) برداشت شده و پس از تهیه برش های بسیار نازک با دستگاه میکروتوم و انجام مراحل رنگ بری و رنگ آمیزی از نمونه ها اسلاید های میکروسکوپی تهیه شد. در این پژوهش طول، عرض و تعداد اشعه چوبی، قطر مماسی آوندهای تابستانه، قطر شعاعی آوندهای بهاره و مساحت حفره آوندهای تابستانه محاسبه شد. نتایج تجزیه و تحلیل داده ها نشان داد که تفاوت معنی داری در سطح احتمال 5 درصد بین قطر مماسی آوندهای تابستانه سالم و بیمار و طول اشعه چوبی در سه طبقه قطری (قطور، متوسط و کم قطر) وجود دارد. اما بین قطر شعاعی و مماسی آوند بهاره در دو طبقه قطری متوسط و کم قطر تفاوت معنی داری دیده نشد. همین طور در طول اشعه چوبی و تعداد سلول ها در مقطع مماسی گونه های سالم و بیمار تفاوت چندانی مشاهده نشد. در اثر نفوذ قارچ در ساختار الیاف چوب درخت شاه بلوط، بی نظمی هایی در مقطع عرضی مشاهده می شود، قارچ، فیبر را بیشتر از اندام های دیگر بافت چوبی مورد حمله قرار می دهد.
    کلیدواژگان: آوندهای چوبی بهاره و تابستانه، اشعه چوبی، فیبر، میکروتوم
  • علی نصرآبادی، محسن مهرور، محمد زکی عقل صفحات 576-580
    ویروس موزائیک کدو (SqMV) یکی از مهم ترین ویروس های آلوده کننده گیاهان خانواده کدو در جهان می باشد. این ویروس متعلق به خانواده Sequviridae و جنس Comovirus بوده، ژنوم آن شامل دو قطعه RNA تک رشته ای مثبت می باشد. در طی ماه های فروردین تا مرداد ماه سال 1393، از گیاهان دارای علائم موزائیک، زردی و پیچیدگی سطح برگ در مزارع کدو، خربزه و هندوانه استان های خراسان رضوی، جنوبی و مازندران نمونه برداری صورت گرفت. آلودگی نمونه های مورد نظر توسط روش RT-PCR با استفاده از آغازگرهای اختصاصی مورد بررسی قرار گرفت، از میان176 نمونه گیاهی جمع آوری شده 10 نمونه آلوده به ویروس موزاییک کدو تشخیص داده شدند، نمونه های آلوده پس از همسانه سازی تعیین ترادف گردیدند. جهت تعیین جایگاه تکاملی این جدایه ها در مقایسه با سایر جدایه های موجود، درخت فیلوژنتیکی توسط نرم افزار MEGA6 رسم گردید. نتایج حاصله بیانگر آن بود که براساس مقایسه ترادف نوکلئوتیدی و آمینو اسیدی، جدایه های ایرانی در دو گروه جداگانه قرار می گیرند.
    کلیدواژگان: ایران، واکنش زنجیره ای پلی مراز، ویروس موزائیک کدو
  • فاطمه عبداللهی، حمیدرضا محمددوست جمن آباد، علی اصغری صفحات 581-591
    به منظور بررسی واکنش رقابتی 18 رقم گندم در رقابت با علف هرز خردل وحشی در سال 93-1392 در دانشکده علوم کشاورزی، دانشگاه محقق اردبیلی انجام شد. تیمارهای آزمایش شامل 18 رقم گندم (البرز، الوند، کرج3، مغان3، MS-81-14، فلات، قدس، نیک نژاد، شاه پسند، سپاهان، روشن، گلستان، آزادی، کرخه، بم، شهریار، یارواروس و سرخ تخم) در شرایط حضور و عدم حضور علف هرز خردل وحشی رشد کردند. آزمایش بصورت فاکتوریل در قالب طرح کاملا تصادفی با سه تکرار به صورت گلدانی اجرا شد. نتایج نشان داد که شاخص سطح برگ در ارقام گندم بین 84/0 تا 09/1 متغیر بود. ارقام الوند و بم بیشترین و ارقام البرز، سپاهان، فلات و روشن کمترین شاخص سطح برگ را داشتند. تداخل علف هرز خردل وحشی درصد پوشش گندم را در مرحله ساقه دهی از 46/42 درصد به 28 درصد کاهش داد. تداخل خردل وحشی عملکرد بیولوژیک را 5/13 درصد و عملکرد اقتصادی را 26 درصد کاهش داد. میزان افت عملکرد دانه در ارقام گندم متفاوت بود. در رقم روشن افت عملکرد بیش از 40 درصد و در ارقام بم، MS-81-14 و یارواروس کمتر از 15 درصد بود. نتایج این آزمایش می تواند در برنامه های مدیریت غیرشیمیایی علف های هرز مورد استفاده قرار گیرد.
    کلیدواژگان: آلودگی محیط زیست، ارقام رقیب، تولید پایدار، مدیریت علف های هرز
  • فریبا میقانی، محمدرضا کرمی نژاد صفحات 592-604
    این آزمایش با هدف بررسی کارایی تعدادی علف کش در کنترل علف های هرز پهن برگ با 12 تیمار و 4 تکرار در یونجه تازه‏کاشت و مستقر طی سال های 93-92 در کرج اجرا شد. تیمارهای اعمال شده در یونجه تازه‏کاشت عبارت بودند از ای پی تی سی 5 لیتر در هکتار، متری بیوزین 750 گرم در هکتار، توفوردی بی 3 و 5/3 لیتر در هکتار، بنتازون 3 لیتر در هکتار، ایمازتاپیر 5/0 و 1 لیتر در هکتار و شاهد بدون کنترل علف هرز. در یونجه مستقر از علف کش متری بیوزین و ای پی تی سی استفاده نشد. بر اساس نتایج آزمایش یونجه تازه‏کاشت، متری بیوزین 750 گرم در هکتار، بنتازون 3 لیتر در هکتار و ایمازتاپیر 1 لیتر در هکتار، در کاهش تراکم خاکشیر ایرانی (Sisymbrium irio)، خاکشیر تلخ (Descurania sophia) و درشتوک (Malcolmia africana) موفق بودند. بهترین تیمارها برای کاهش زیست توده خاکشیر ایرانی، بنتازون 3 لیتر در هکتار و ایمازتاپیر 5/0 و 1 لیتر در هکتار، خاکشیر تلخ (علاوه بر آنها) متری بیوزین 750 گرم در هکتار و درشتوک (علاوه بر تیمارهای ذکر شده) توفوردی بی 3 و 5/3 لیتر در هکتار بودند. مناسب ترین تیمار برای افزایش عملکرد یونجه تازه کاشت در چین اول، ایمازتاپیر 1 لیتر در هکتار، در چین دوم، ایمازتاپیر 5/0 و 1 لیتر در هکتار، بنتازون 3 لیتر در هکتار و توفوردی‏بی 3 لیتر در هکتار و در چین سوم، ایمازتاپیر 5/0 و 1 لیتر در هکتار، توفوردی‏بی 3 و 5/3 لیتر در هکتار و بنتازون 3 لیتر در هکتار بودند. متری‏بیوزین باعث کاهش عملکرد یونجه تازه کاشت شد. در یونجه مستقر، بهترین تیمار برای کاهش تراکم کاهوی وحشی، توفوردی‏بی 5/3 لیتر در هکتار و بهترین تیمار برای کاهش زیست توده آن، توفوردی‏بی 5/3 لیتر در هکتار و ایمازتاپیر 5/0 و 1 لیتر در هکتار بود. بهترین تیمار برای افزایش عملکرد یونجه مستقر در چین اول، ایمازتاپیر 5/0 و 1 لیتر در هکتار و در چین دوم، ایمازتاپیر 1 لیتر در هکتار، بنتازون 3 لیتر در هکتار و توفوردی‏بی 5/3 لیتر در هکتار و در چین سوم، تمام تیمارها بجز توفوردی‏بی 3 لیتر در هکتار و متری‏بیوزین 750 گرم در هکتار بود. در مجموع کاربرد دز مناسب علف-کش های ایمازتاپیر، بنتازون و توفوردی بی بر حسب نوع علف هرز می تواند علاوه بر کنترل مطلوب علف های هرز، در افزایش عملکرد علوفه یونجه موثر باشد.
    کلیدواژگان: تراکم، زیست توده، علف کش، علف هرز پهن برگ، عملکرد
  • سحر جنتی عطایی، همت الله پیردشتی، حسین کاظمی، معصومه یونس آبادی صفحات 605-616
    به منظور شناسایی گیاگان و تهیه نقشه پراکنش علف های هرز مزارع کلزا در شهرستان گرگان، تعداد 58 مزرعه این شهرستان در سال 1394 انتخاب و گونه های علف های هرز، براساس الگوی W در این مزارع نمونه برداری و شناسایی شدند. با استفاده از روابط موجود، تراکم، فراوانی، یکنواختی و غالبیت هرگونه بدست آمد. در هر مزرعه طول و عرض جغرافیایی و ارتفاع از سطح دریای مکان مورد نمونه برداری توسط دستگاه GPS ثبت شد. اطلاعات بدست آمده با استفاده از نرم افزار Arc GIS نسخه 3/9 پردازش و نقشه پراکنش کلیه علف های هرز مزارع کلزا تهیه شد. نتایج نشان داد که در مزارع کلزای شهرستان گرگان 35 گونه علف هرز وجود دارد که متعلق به 18 خانواده گیاهی می باشد. 1/17 درصد گونه ها متعلق به تیره گندمیان (Poaceae) و 4/11 درصد متعلق به تیره کاسنی (Asteraceae) و بقیه به 16 خانواده گیاهی دیگر تعلق داشتند. در مجموع 2/77 درصد گونه ها یک ساله، 8/22 درصد گونه ها چندساله، 80 درصد دولپه و 20 درصد تک لپه بودند. با توجه به شاخص غالبیت، مهم ترین رستنی های مزاحم در مزارع کلزای شهرستان گرگان به ترتیب اهمیت، شامل: علف خونی (Phalaris minor) با غالبیت نسبی 5/45 درصد، یونجه زرد (Melilotus officinalis) با غالبیت نسبی 4/29 درصد، شلمی (Rapistrum rugosum) با غالبیت نسبی 9/28 درصد و یولاف وحشی (Avena ludoviciana) با غالبیت نسبی 5/23 درصد بودند. شناخت علف های هرز مهم کلزا و نحوه پراکنش آن ها با استفاده از رهیافت های جدید، امری مهم در پیشبرد راه کارهای مدیریتی می باشد.
    کلیدواژگان: سامانه اطلاعات جغرافیایی، شاخص غالبیت، فراوانی، نقشه پراکنش، یکنواختی
  • احسان الله زیدعلی، روح الله مرادی، فرشته دارابی، زینب رستمی صفحات 617-627
    جوانه زنی گیاهان واکنش متفاوتی به نانو ذرات نشان می دهد. کاربرد نانو ذره‏ای که تاثیر مثبت بر جوانه زنی و رشد گیاه زراعی و تاثیر منفی بر علف هرز داشته باشد، می تواند در کنترل علف هرز مفید باشد. جهت بررسی تاثیر غلظت‏های مختلف نانو اکسید روی بر خصوصیات جوانه‏زنی یولاف وحشی و دو ژنوتیپ گندم، آزمایشی به صورت فاکتوریل در قالب طرح کاملا تصادفی با چهار تکرار در آزمایشگاه دانشکده کشاورزی دانشگاه ایلام در سال 1395 انجام شد. فاکتورهای آزمایش شامل ژنوتیپ گیاهی در سه سطح (ارقام بهرنگ و سیوند گندم و یولاف وحشی) و نانو اکسید روی در چهار سطح (صفر (شاهد)، 10، 100 و 500 پی‏پی‏ام) بود. نتایج نشان داد که نانو ذرات اکسید روی و ژنوتیپ و اثر متقابل آنها تاثیر معنی‏داری (01/0P≤) بر تمامی ‏صفات مورد بررسی داشتند. طول ساقه‏چه هر دو رقم گندم تا سطح 100 پی‏پی‏ام نانو ذره افزایش و پس از آن کاهش یافت. درحالی که افزایش هر کدام از سطوح نانو ذره باعث کاهش معنی‏دار طول ساقه‏چه یولاف وحشی شد. افزایش سطوح نانو ذره تا سطح 10 پی‏پی‏ام منجر به افزایش معنی‏دار طول ریشه‏چه یولاف وحشی و رقم سیوند گندم شد و از این غلظت به بعد این صفت کاهش یافت. طول ریشه چه رقم بهرنگ گندم با افزایش غلظت نانو ذره حدود 71 درصد کاهش نشان داد. غلظت‏های مختلف نانو اکسید روی تاثیر معنی‏داری بر وزن خشک رقم سیوند گندم نشان نداد ولی باعث کاهش این صفت در رقم بهرنگ و افزایش در یولاف وحشی شد. تاثیر غلظت نانو ذره بر وزن خشک ساقه یولاف و رقم بهرنگ منفی و بر رقم سیوند مثبت بود. سرعت و درصد جوانه‏زنی ارقام گندم تحت تاثیر نانو ذره قرار نگرفت ولی غلظت 500 پی‏پی‏ام نانو اکسید روی باعث افزایش حدود 63 درصدی این صفات در یولاف وحشی شد. بطور کلی، نتایج نشان داد که استفاده از نانو ذرات اکسید روی در زراعت گندم می‏تواند منجر به جوانه‏زنی و رشد بیشتر علف هرز یولاف وحشی نسبت به گندم و درنتیجه نیاز به هزینه و تلاش بیشتر جهت کنترل علف‏هرز گردد و توصیه نمی‏شود.
    کلیدواژگان: ریشه چه، ژنوتیپ، ساقه چه، سرعت جوانه زنی، شاخص جوانه زنی
  • حشمت الله زرین جوب، محمدحسین قرینه، جاوید قرخلو، الهام الهی فرد صفحات 628-638
    تاثیر دزهای علف کش بر رقابت گندم با علف هرز خردل وحشی به منظور توسعه یک مدل ترکیبی برای برآورد دز بهینه علف کش برای مهار تراکم معینی از علف هرز مورد بررسی قرار گرفت. آزمایش مزرعه ای در سال زراعی 95-94 بصورت کرت های خرد شده فاکتوریل در قالب طرح پایه بلوک های کامل تصادفی در دانشگاه کشاورزی و منابع طبیعی رامین خوزستان انجام شد. دو رقم گندم چمران و وریناک به عنوان فاکتور اصلی در نظر گرفته شدند. دز علف کش «یدوسولفورون متیل سدیم + مزوسولفورون متیل+ مفن پایر دی اتیل» در پنج سطح شامل 2/0، 4/0، 6/0، 8/0 و 1 برابر دز توصیه شده (5/1 لیتر در هکتار) و تراکم علف هرز خردل وحشی شامل 0، 12، 24 و 36 بوته در متر مربع بصورت فاکتوریل در داخل کرت های اصلی اجرا شدند. ترکیبی از مدل هذلولی راست گوشه و منحنی دز-پاسخ استاندارد بخوبی تاثیر دز علف کش و رقابت علف هرز خردل وحشی بر تولید زیست توده گندم را توصیف کرد. زیست توده خردل وحشی در تراکم 36 بوته در متر مربع با مصرف نیمی از دز توصیه شده علف کش «یدوسولفورون متیل سدیم + مزوسولفورون متیل + مفن پایر دی اتیل» در رقم گندم وریناک معادل 74/82 گرم در متر مربع و در رقم گندم چمران معادل 91/39 گرم در متر مربع پیش بینی شد. همچنین، تولید زیست توده گندم با مصرف تنها نیمی از دز توصیه شده از علف کش در بیشترین تراکم مورد ارزیابی خردل وحشی برای رقم وریناک معادل 31/569 گرم در متر مربع و برای رقم چمران معادل 49/720 گرم در متر مربع پیش بینی شد.
    کلیدواژگان: دز-پاسخ، رقابت، مدل سازی، یدوسولفورون متیل سدیم + مزوسولفورون متیل + مفن پایر دی اتیل
  • صدیقه اشتری صفحات 639-644
    این آفت در برابر سموم شیمیایی به شدت از خود مقاومت نشان داده و از نظر کمی و کیفی عملکرد پنبه را کاهش می‏دهد. حشره‏کش های مانوس با محیط زیست به دلیل داشتن خصوصیات ویژه از جمله کمتر بر هم زدن محیط زیست حشره‏کش های مطلوبی هستند، در این تحقیق حساسیت مراحل مختلف زیستی سفید بالک پنبه Bemisia tabaci نسبت به پایری‏پروکسی‏فن، روغن سیتوویت و مخلوط آنها ارزیابی گردید. از روغن سیتوویت و پایری‏پروکسی‏فن در پنج غلظت و تیمار شاهد استفاده شد. مقدار LC50 حشره کش پایری‏پروکسی‏فن برای حشره‏ کامل، تخم، مراحل نابالغ به ترتیب 1086، 0451/45 و4716/11 پی‏پی‏ام تعیین گردید. LC50 روغن سیتوویت برای حشره‏ کامل، تخم، مراحل نابالغ به ترتیب 1554، 7920/884 و 7002/684 پی‏پی‏ام برآورد شد. به منظور ارزیابی نقش سینرژیستی روغن سیتوویت LC25 سم پا یری پروکسی‏فن در هر مرحله زیستی با LC25 روغن سیتوویت مخلوط گردید که در نتیجه میزان تلفات در حشره ‏کامل، تخم و مراحل نابالغ به ترتیب 36/52% ،32/62% و 19/69% بدست آمد. و معلوم گردید که روغن سیتوویت اثر پایری‏پروکسی‏فن را تشدید می‏کند.
    کلیدواژگان: پایری پروکسی فن، روغن، زیست سنجی، سینرژیسم
  • مجید محمودی، حسین پژمان، مجید میراب بالو صفحات 645-652
    تریپس غربی گل Frankliniella occidentalis (Pergande) یکی از مهم ترین آفات درختان میوه در فصل گل دهی در دنیا به شمار می آید. استفاده از تله های رنگی و حشره کش ها در مدیریت کنترل این حشره بسیار متداول است. در این پژوهش میزان جلب حشرات کامل توسط سه نوع تله رنگی (زرد، آبی و سفید) و کارآیی پنج ترکیب آفت کش (دلتامترین + ایمیداکلوپراید، استامی پراید، آنتی فیدنت، آزادیراختین و اکسی دیمتون متیل) علیه این آفت در قالب دو طرح بلوک کامل تصادفی مجزا در یک باغ سیب در حومه شهر شیراز بررسی شد. نتایج به صورت میانگین تراکم تریپس غربی گل در 25 سانتی متر سرشاخه و درصد کاهش جمعیت بر اساس فرمول هندرسون-تیلتون برآورد شد. نتایج مربوط به تله های رنگی نشان داد در همه تاریخ های نمونه برداری تله های آبی رنگ نسبت به دیگر تله ها به طور معنی داری تعداد بیشتری تریپس گل را جلب کردند. به طور میانگین تله های آبی رنگ 85/13 ± 31/34، تله های زرد 78/4 ± 56/12 و تله های سفید 83/1 ± 87/4 تریپس غربی گل جلب کردند. نتایج تجزیه واریانس داده های مربوط به 14 روز پس از کاربرد آفت کش ها حاکی از تاثیر معنی دار تیمارها بر تراکم جمعیت تریپس غربی گل بود و مقایسه میانگین ها نشان داد تیمار دلتامترین+ایمیداکلوپراید، استامی پراید و آنتی فیدنت با شاهد اختلاف معنی داری دارند. میانگین درصد تلفات آفت در تیمارهای دلتامترین + ایمیداکلوپراید، استامی پراید، آنتی فیدنت، آزادیراختین و اکسی دیمتون متیل 14 روز پس از کاربرد آفتکش ها به ترتیب 7/77، 3/83، 1/70، 6/25 و 9/29 درصد تعیین شد. در مجموع، کاربرد تله های چسبی آبی رنگ و مخلوط حشره کش دلتامترین+ ایمیداکلوپراید، استامی پراید و آنتی فیدنت در برنامه مدیریت کنترل تریپس غربی گل مناسب به نظر می رسد.
    کلیدواژگان: استامی پراید، ایمیداکلوپراید، دلتامترین، کارت چسبنده آبی
  • امین رادمرد تیتکانلو، سعید نصرالله نژاد، رحیم احمدوند، عباس رضایی اصل، فروه سادات مصطفوی نیشابوری صفحات 653-661
    ویروس ایکس سیب زمینی (Potato virus X; (PVX)) یکی از مخرب ترین ویروس های توتون در مزارع می باشد، که با توجه به تلاش های صورت گرفته برای کنترل این ویروس، تاکنون روش مناسبی برای کنترل این ویروس ارائه نشده است. در مطالعه حاضر به منظور بررسی اثر میدان الکترومغناطیسی روی کنترل این ویروس، آزمایشی در قالب طرح کاملا تصادفی در یازده تیمار (10، 50 و 90 میلی تسلا در مدت زمان های 60، 90 و 120 دقیقه روی گیاهچه های توتون آلوده به ویروس و دو تیمار شاهد، یکی آلوده و دیگری عاری از آلوگی به ویروس) و در شش تکرار بر روی نهال توتون به اجرا درآمد. پس از مایه زنی گیاهچه ها در مرحله چهار برگی، آنالیز نتایج حاصل از آزمون الایزا دوطرفه با آنتی سرم چندهمسانه ای PVX نمونه ها بررسی شد. همچنین میزان اسیدسالیسیلیک و آنزیم فنیل آلانین آمونیالیاز که در مقاومت سیستمیک اکتسابی و مکانیسم دفاعی گیاه دخالت دارند، در تیمارهای مورد بررسی اندازه گیری شد، به طوری که برای ارزیابی اسید سالیسیلیک از HPLC و برای سنجش فنیل آلانین آمونیالیاز براساس تشکیل ترانس سینامیک اسید استفاده گردید. نتایج نشان داد که میدان الکترومغناطیس میزان کدورت سنجی ویروس را در گیاه توتون کاهش داده و میزان اسید سالیسیلیک و آنزیم فنیل آلانین آمونیالیاز را افزایش می دهد. بر این اساس، برای میزان کدورت سنجی ویروس تیمار 8 (100 میلی تسلا و 120 دقیقه) و برای فعال کردن مکانسیم دفاعی گیاه تیمار 7 (50 میلی تسلا و 60 دقیقه) بهترین تیمار تشخیص داده شد. با توجه به نتایج می توان استفاده از الکترومغناطیس را بعنوان یک روش مناسب و جدید برای کنترل PVX در نهال های توتون در خزانه پیشنهاد کرد.
    کلیدواژگان: کنترل ویروس، مقاومت اکتسابی سیستمیک، میدان های ضعیف مغناطیسی
  • سارا پرنده، سید وحید اسلامی، مجید جامی الاحمدی صفحات 662-675
    به منظور بررسی توان رقابتی علف هرز تاج خروس سفید در مزرعه ارزن و واکنش رشد و عملکرد این گیاهان به برهم کنش مقادیر مختلف تشعشع و نیتروژن، دو آزمایش مجزا بصورت کرت های خرد شده در قالب طرح بلوک های کامل تصادفی با سه تکرار در سال 1394 در مزرعه تحقیقاتی دانشکده کشاورزی دانشگاه بیرجند انجام گرفت. تشعشع به عنوان عامل اصلی در سه سطح (عدم سایه دهی، 41 و 75 درصد سایه دهی) و تراکم تاج خروس سفید به عنوان عامل فرعی در سه سطح (0، 12 و 24 بوته در متر مربع) در دو آزمایش مجزا، یکی در شرایط کاربرد 150 کیلوگرم در هکتار کود نیتروژن و دیگری در شرایط عدم کاربرد نیتروژن بررسی گردید. کاربرد نیتروژن باعث افزایش معنی دار ارتفاع، درصد ورس، تعداد برگ، طول پانیکول، زیست توده و عملکرد دانه ارزن و همچنین ارتفاع تاج خروس سفید گردید. سایه دهی در سطح 75 درصد منجر به افزایش درصد ورس ارزن و کاهش زیست توده و عملکرد دانه آن گردید و در عین حال ارتفاع بوته تاج خروس را افزایش و تعداد شاخه و بذر آن را کاهش داد. تاثیر تراکم تاج خروس سفید نیز بر ارتفاع، قطر ساقه و عملکرد دانه ارزن و همچنین ارتفاع، تعداد شاخه های فرعی و تعداد بذر در بوته تاج خروس سفید معنی دار بود و در بالاترین سطح منجر به کاهش 21 درصدی عملکرد دانه ارزن در مقایسه با شاهد گردید. بر اساس نتایج، سایه می تواند باعث کاهش تعداد شاخه های فرعی و کاهش تولید بذر در تاج خروس شود. همچنین به نظر می رسد کمبود نیتروژن، کاهش قدرت رقابت علف هرز و از طرف دیگر کاهش تولید بذر و ایجاد آلودگی کمتری را به دنبال دارد.
    کلیدواژگان: تداخل، سایه دهی، صفات مورفولوژیک، عملکرد
  • اعظم حاتمی همپا، عبدالله جوانمرد، محمد تقی آل ابراهیم، امید سفالیان صفحات 676-689
    به منظور ارزیابی اثرات آللوپاتیک عصاره سورگوم و تلخه بر شاخص های جوانه زنی گندم، چغندرقند، سلمه تره و تاج خروس، آزمایشی به صورت فاکتوریل بر پایه طرح کاملا تصادفی با سه تکرار در دانشکده کشاورزی دانشگاه مراغه در سال 1395 اجرا شد. فاکتورها شامل عصاره آبی اندام هوایی تلخه و سورگوم و غلظت عصاره آبی (0، 5، 10 و 20 درصد حجمی) بودند. نتایج نشان داد که درصد و میزان جوانه زنی، طول ریشه چه و ساقه چه، وزن خشک ریشه چه، ساقه چه و وزن خشک گیاهچه گیاهان مورد مطالعه با افزایش غلظت عصاره سورگوم و تلخه کاهش معنی داری پیدا کردند. درصد جوانه زنی با عصاره تلخه 62/12 درصد بیشتر از عصاره سورگوم بود. علاوه بر این، اثر بازدارندگی عصاره سورگوم بر کاهش سرعت جوانه زنی علف های هرز بیشتر از تلخه بود. کاهش طول ریشه چه تاج خروس با کاربرد عصاره تلخه بیشتر از عصاره سورگوم بود. به طوری که، طول ریشه چه تاج خروس با کاربرد 20 درصد عصاره تلخه 13/73 درصد کاهش یافت. در میان گیاهان زراعی نیز طول ریشه چه چغندرقند با کاربرد عصاره تلخه 88/81 درصد نسبت به شاهد کاهش نشان داد. همچنین کاهش بنیه بذر در تمامی غلظت های سورگوم بیشتر از تلخه بود. با افزایش غلظت عصاره سورگوم، شاخص بنیه بذر سلمه تره و تاج خروس به ترتیب 36/83 و 15/87 درصد نسبت به شاهد کاهش نشان داد. علاوه بر این، کمترین طول ساقه چه و گیاهچه در علف های هرز سلمه تره و تاج خروس با کاربرد 20 درصد عصاره سورگوم و تلخه مشاهده شد. همچنین با افزایش غلظت عصاره تلخه و سورگوم، میزان فعالیت آنزیم های پراکسیداز و پلی فنل اکسیداز 65/53 و 78/10 درصد به ترتیب افزایش و کاهش یافتند. شاخص تحمل مشخص کرد که تاج خروس و سلمه تره حساسیت بیشتری به عصاره آبی سورگوم و تلخه دارند. بنابراین با توجه به اثر بازدارندگی عصاره آبی تلخه و سورگوم بر میزان جوانه زنی و قدرت گیاهچه، می توان از آن ها بهعنوان علف کش های طبیعی در کنترل علف های هرز استفاده کرد.
    کلیدواژگان: بنیه بذر، تاج خروس، پلی فنل اکسیداز، سلمه تره، شاخص تحمل علف هرز
  • مرجان دیانت صفحات 690-699
    جوانه زنی بذر در مدیریت علف های هرز فرآیندی کلیدی است بطوری که می تواند بر تعداد علف های هرز سبز شده و زمان سبز شدن آنها تعیین کننده باشد. تاج خروس خزنده و خوابیده از جمله علف های هرز مهم سبزیجات و گیاهان زراعی تابستانه در ایران هستند. به منظور ارزیابی اثر دما بر جوانه زنی این دو علف هرز، آزمایشی در قالب طرح کاملا تصادفی و با 4 تکرار در دانشگاه آزاد اسلامی- واحد علوم و تحقیقات در سال 1394 انجام شد. بذور با دماهای 5، 10، 15، 20، 25، 30، 35، 40 و 45 درجه سانتی گراد تیمار شدند. با توجه به مدل خطوط متقاطع دماهای پایه، بهینه و بیشینه به ترتیب در تاج خروس خزنده 37/14، 21/34 و 50/44 و در تاج خروس خوابیده 24/14، 65/31 و 20/44 درجه سانتی گراد به دست آمدند. در آزمایشی دیگر 7 سطح پتانسیل اسمزی (0، 2/0-، 4/0-، 6/0-، 8/0- و 1- مگاپاسکال) مورد بررسی قرار گرفتند. به منظور ارزیابی پتانسیل سطوح مختلف تنش خشکی در کاهش درصد جوانه زنی بذر از مدل سیگموئید سه پارامتری استفاده شد. به طور کلی مقادیر x50 (پتاسیل لازم برای کاهش 50 درصدی جوانه زنی) به دست آمده برای تاج خروس خوابیده نسبت به تاج خروس خزنده کمتر بود. تاج خروس خزنده در پتانسیل 1- مگاپاسکال توانست 25/9 درصد جوانه زند ولی در این پتانسیل تاج خروس خوابیده جوانه نزد که نشان دهنده تحمل بالاتر تنش خشکی توسط این گونه بود. با توجه به داده های به دست آمده هر دو گونه می توانند در اقلیم های نیمه گرم و گرم جوانه زنند. تحمل هر دو گونه نسبت به تنش خشکی بالا بود اما تاج خروس خزنده تحمل بالاتری داشته و بنابراین پتانسیل تهاجم بیشتری به مناطق خشک دارد.
    کلیدواژگان: دمای بهینه جوانه زنی، علف هرز، مدل خطوط متقاطع، مدل سیگموئیدی
  • یعقوب محمد علیان، سیده نجمه بنی هاشمیان، مرتضی گل محمدی، سید مهدی بنی هاشمیان، سمانه بشیری صفحات 700-705
    نماتد مرکبات (Tylenchulus semipenetrans) یکی از مهمترین نماتدهای پارازیت درختان مرکبات است که به طور وسیعی در باغ های مرکبات دنیا گسترش داشته و باعث زوال تدریجی درختان و کاهش محصول می شود. این تحقیق با هدف بررسی تحمل پایه های رایج مرکبات کشور نسبت به نماتد مرکبات انجام شد و در آن واکنش پایه های مرکبات شامل سیتروملو (Citrus paradisi (M.) × Poncirus trifoliata (L.) Raf.)، پونسیروس (P. trifoliata (L.) R.)، نارنج (C. aurantium L.)، بکرایی (Citrus sp.)، راف لمون (C. Jambhiri Lush) و آف تایپ نارنج (Citrus aurantiam CV. Offtype) نسبت به نماتد مرکبات، تحت شرایط کنترل شده در گلخانه به مدت دو سال متوالی بررسی شد. نهال های سه ماهه این پایه ها در قالب طرح کاملا تصادفی با پنج تکرار در گلدان هایی با جمعیت 40 عدد لارو سن دوم نماتد در هر سانتیمتر مکعب خاک کاشته شد و بعد از گذشت شش ماه میزان آلودگی ریشه ها بررسی شد. نتایج آزمایش براساس آزمون LSD در هر دو سال متوالی نشان داد که سیتروملو و پونسیروس با کمترین میزان جمعیت نماتد ماده بالغ در روی ریشه، اختلاف آماری معنی داری با سایر تیمارها دارند.
    کلیدواژگان: پونسیروس، راف لمون، سیتروملو، نارنج، نماتد
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  • Abbas Abbasian, Mohammad Hassan Rashed Mohassel, Ahmad Nezami, Ebrahim Izadi Darbandi Pages 548-557
    Introduction
    Weed cause enormous loss of chickpea yield and its quality. Photocontrol of weeds (soil cultivation in darkness) is a preventive weed control method, the basic aim of which is to reduce the germination of light sensitive weed seeds by excluding light during soil disturbance, in order to reduce the emergence of weeds in the crop. Considerable research has examined the potential use of lower-than-labeled herbicide doses. There are reasons for the potential successful use of reduced herbicide doses: (i) registered doses are set to ensure adequate control over a wide spectrum of weed species, weed densities, growth stages, and environmental conditions; (ii) maximum weed control is not always necessary for optimal crop yields; and (iii) combining reduced doses of herbicides with other management practices, such as tillage or competitive crops, can markedly increase the odds of successful weed control. This study was conducted to evaluate the photocontrol of weeds and application of reduced dosage of Imazethapyr and trifluralin herbicides on weed control and yield of chickpea.
    Materials And Methods
    The experiment was designed as a strip plot based on a complete randomized block with three replications. The experiment had 3 factors: main plot consisted of tillage method at 3 levels (night tillage, day tillage, light-proof cover tillage), subplot consisted of Trifuralin (480, 960 and 1440 grams of active ingredient per hectare) Imazethapyr (50, 100 and 150 grams of active ingredient per hectare), weed infestation and weed free were considered as control. During the growing season, six sampling steps (28 days after planting (410 Growth Degree Day (GDD)), (45 days after planting (715 GDD)), (57 days after planting (975 GDD)), (70 days after planting (1280 GDD), (75 days after planting (1620 GDD)), (90 days after planting (2025 GGD)) were carried out. For statistical analysis the data normality of the distribution were analyzed with Sigma plot software, and if necessary, the data transforming and then ANOVA was performed using MSTATC. The means were compared using Duncan's multiple range test and graphs were drawn using Excel and Sigma plot software.
    Result and
    Discussion
    In the growing season, the application of herbicide had significant effect (P≤ 0.05) on weed density. In all stages of sampling, weed density was higher in light-proof cover tillage treatments than day and night tillage operations. According to the results based on the type of tillage, night tillage and light-proof cover tillage treatments did not reduce weed density compared to day tillage. In the reduced Imazethapyr application, there was significant difference at 1620 GDD with others, but this amount of application did not effectively control weeds. In treatment of 1280 GDD, the amount of reduced application of Trifuralin was significantly different with other amounts but could not control weeds. However, there was no significant difference between the amounts of Trifuralin from this stage until the end of the growth season. By examining the biomass of chickpea during the growing season in the applied amounts of herbicides, it was determined that the growth of all treatments was the same order of 1200 GDD. From this stage, the difference between treatments increased until the end of the growing season, in the end of the growing season, control of weed control was the highest and control without chickpea was the least biomass. The effect of herbicide application dosage on the density of the weeds was significant (P≤ 0.05). Chickpea grain yield in light -proof cover tillage was 45 percentage lower than night-time tillage and day time tillage treatment and there were no significant differences between night-time tillage and day-time tillage treatment. The lowest and the highest yield was respectively in weed infestation (1151 Kg/ha) and weed control (1977 Kg/ha) and yield in the dosage of herbicides. Did not differ significantly. The results of this experiment show that reduced dosage of herbicides can control weed without negative effects on chickpea yield.
    Conclusion
    The results showed that weed density and weed biomass was more than in light-proof cover tillage treatment compared to night and day tillage and there were no significant differences (P≤ 0.05) between night and day tillage. Weed biomass showed no significant differences between herbicide treatments. The reduced dosage of herbicide in Imazethapyr treatment did not have enough control but there were no significant differences between herbicide treatments. Chickpea yield had no significant difference (P≤ 0.05) between reduced, recommended and increased dosage herbicides
    Keywords: Night tillage, Pursuit, Treflan
  • Sobhan Mahzari, Mohammad Ali Baghestani Pages 558-567
    Introduction
    Garlic (Allium sativum L.) is an important winter crop in northern of Iran with a total of 9580 ha which produces approximately 90, 197 tons per year. It is the second most widely cultivated species of the genus, Allium after onion (Allium cepa). Also, Garlic along with onions and leeks are three major cultivated species in Alliaceae family. This plant because of high economic and medicinal values is cultivated in 2610 hectares of agricultural lands of Mazandaran Province, Iran. Slow growth rate, low height, and a thin canopy that does not cover the soil enough to sup-press weeds make garlic a poor competitor against the latter until the beginning of spring. According results, reported 71% yield losses in garlic crop if weeds are allowed to grow during the crop season. Weed interference is affected by the time of weed emergence relative to the crop’s phenological development. The weeds, which emerge early or simultaneously with the crop, are highly competitive and should be managed by farmers. Most weed management strategies in cereals target seedlings, as they are the most sensitive stage of the weed. However, emergence of weed seedlings varies every year in timing, extent and intensity. Therefore in this study, the effect of chemical management on reducing the density and biomass of weeds, yield and agronomic characteristics of garlic were studied in Mazandaran Province, Iran.
    Materials And Methods
    After the selection of location test, in order to determine the physical and chemical properties before the preparation of soil for planting, sampling from the soil was carried out from the depth of 0 to 30 cm at some point. The farm was plowed using a moldboard plow, then the used fertilizers in this study were added to the soil twice before planting and then the fertilizers were incorporated with the soil using a Disc. The amount of used fertilizers in this study according to soil test were including: 200 kg Urea per hectare that 100 kg as the base and 50 kg in two foliage stage and 50 kg in 4 foliage stage of garlic, 200 kg superphosphate triple per hectare, and 100 kg potassium sulfate. The research was performed in a land with area of 300 m2 containing 30 plots with dimensions of 3×3 m2. The planting process was done after disinfection of garlic seed varieties of Mazand for 24 hours in a solution of 2% carboxin thiram with the distance of 30×15 cm and the density of 23 plants per m2on 23/10/2012. After about two weeks from planting of garlic, germination was fully performed. The studied factors in 10 dosages of herbicide are including: 1.5, 2 and 2.5 liters per hectare of Trifluralin (Terflan) via formulations (EC 48%), 1.5, 2 and 2.5 liters per hectare of Oxyfluorfen, 1.5 liters per hectare of Oxyfluorfen in two stages (the half in first stage and the rest 18 days later) via formulations (EC 24%), hand weeding control and lack of weeding control (the number of replications of these two treatments were two folds of others (2 replications in each block and 6 replications in total)). Two weeks before planting Trifluralin herbicides were incorporated with the soil and Oxyfluorfen herbicides as post-emergently were applied in the 3 to 4 foliage stages of weeds using a backpack sprayer pump from the side of the nozzle sag (T-Jet). After 145 days from planting, 10 plants per plot were selected and plant heights measured. After maturity of garlics, 10 plants of garlic were eradicated and the number of cloves per bulb was counted and weight of 100 cloves of garlic was weighed. After full maturity of garlic, a square meter of each plot was harvested on 7.5.2013 and the harvested plants was placed for 48 hours in the farm and then bulb yield and biological yield were weighed and harvest index was also calculated. Statistical analysis software SAS (version 9.1) was used for analysis and the obtained averages were compared by means of the Duncan least significant difference test.
    Results And Discussion
    Results showed that the use of different doses of various herbicides had a significant difference on the plant height, weight of 100 cloves, economical and biological yield and harvest index of garlic. In contrast, under treatments of the usage of 1.5 liter of Oxyfluorfen in two stages and hand weeding treatment, plant height of garlic was increased due to lack of competition with weed species and no significant difference was observed between the above treatments with the usage of 1.5, 2 and 2.5 liters of Oxyfluorfen. The adverse effect and phytotoxicity of garlic under the use of different doses of 2 and 2.5 liters of Oxyfluorfen caused disturbances in the production of cloves per bulb of garlic and the plant spent their photosynthetic products in the reclamation of its shoots. In contrast, the highest number of cloves per bulb were counted under the treatments of using 1.5 liter of Oxyfluorfen, hand weeding and 1.5 liter of Oxyfluorfen in two stages. The results showed that the highest economical yield of garlic was obtained in the treatment of using 1.5 liter of Oxyfluorfen, hand weeding treatment and splitting of 1.5 liter of Oxyfluorfen in two stages, and there were no significant differences between the above treatments. The plant used the best from the resulted ecological niche in normal conditions, and it could transfer more photosynthetic materials to the reproductive organs and it could increase the bulb yield with more producing of cloves per bulb with higher weight.
    Conclusion
    The results obtained from experimental trials on plant height, cloves number in the bulb, cloves weight and ultimately economic yield of garlic (bulb) showed that the treatment of using 1.5 liters of Oxyfluorfen in 3 to 4 foliage stages of weed species was the best treatment.
    Keywords: Biomass, Economic yield, Garlic, Oxyfluorfen, Trifluralin, Weed
  • Afrooz Hasani Boosari, Javad Torkaman, Mehrdad Ghodskhah Daryaei Pages 568-575
    Introduction
    Chestnut (Castanea sativa) trees are generally distributed in the northern part of Iran. Chestnut trees provide eaten fruit and good-quality timber in many countries. Dried chestnut wood has a high resistance to decay due to extractive compounds, such as tannins. Chestnut wood is used for many applications, such as the construction of buildings and wooden furniture, shipbuilding, timbers, and musical instruments. This important tree species was used extensively until the occurence of the fatal disease chestnut blight (CBD) caused by Cryphonectria parasitica, which is a tree pathogen notable for the disease commonly known as chestnut blight, which primarily affects species of sweet chestnut including the American sweet chestnut (Castanea dentata) and European sweet chestnut (C. sativa). The pathogen has been referred to as the chestnut blight fungus. Castanea sativa has a ring-porous wood with larger early wood vessels formed in the spring. The aim of this study was to determine and compare the anatomy and the xylem vessels diameter and some ray attributes of diseased chestnut wood and healthy chestnut wood in the north of Iran.
    Material and
    Methods
    The sample tree was 20 m in height and 15-40 cm in diameter. The tests specimens were taken at 1.30 m height above the ground in the form of a disc that includes the infected area. In this study the effect of the Cryphonectria parasitica was investigated in wooden and bark samples from healthy and diseased trees in three diameter classes (small medium and large). Both diseased and healthy wood samples with dimensions of 2 x 2 x 2 cm were taken from a diseased chestnut tree to determine the anatomical features of thin (8-15 μm) transverse, radial, and tangential sections. This was done by using a microtome (Leica 820, Germany) for the light microscopical study of wood anatomy. All of the anatomical sections were prepared as recommended by Parsa pajouh and Schweingruber (1988). Then, some thin transversal section were prepared and after different stages of staining, microscope slides were prepared. To achieve statistically reliable results, the guidance provided by The International Association of Wood Anatomists Committee - IAWA Committee (1989) was used to determine the Tangential and Radial diameter of the Spring and summer vessels, and the width, height and number of rays in both healthy and diseased wood .To analysis of data used Anova and t-student tests and for compare mean Duncan test by Spss software.
    Results And Discussion
    Table 2 and 3 provide the average values of the radial and tangential diameter of the healthy and diseased wood vessels and frequency of the rays with their average of width and height. In both of the healthy and diseased parts of the chestnut wood, ring porosity was present, and the annual rings were distinct. The porosity and distinctness of the annual rings were not changed in the diseased wood. However, the tangential diameter of the vessels was 71.93 μm in the summer wood of the diseased part and 65.04 μm in the summer wood of the healthy part. These diameters for the spring wood were determined 457.25 μm and 337.21 μm, respectively. The tangential and radial diameters of the vessels were smaller in the healthy wood than in the diseased wood. The average vessel frequency in the springwood of the diseased and healthy parts were 6 and 6.2, respectively. The vessel frequency values in the summer wood were determined to be 44 and 29, respectively. The results showed that there was significant difference between summer vessel diameter in the three classes of diameter (large, medium and small diameter) at probability level of 5%, in diseased and healthy wood. Whereas the diameter of the radial and tangential spring vessels in diameter classes had no significant difference between medium and low diameter. The irregularities were observed in cross-section due to influence of fungi on structure of wooden fiber in chestnut, the fungi attacks wooden fiber more than other organs of trees. The irregular cell structure of the vessels and fibers of the diseased wood showed (Fig.5) some similarity with cancer in animals and humans.
    Conclusion
    This is the first detailed study that has been conducted on Cryphonectria parasitica diseased Iranian Chestnut trees. One way to prevent the spread of the disease in forests is to remove the diseased trees. These logs can be used in making furniture, shipbuilding, wooden building construction, and musical instruments. Heat treatment can be suggested for more dimensional stability and especially for sterilization of the timber obtained from the diseased trees.
    Keywords: Fiber, Microtome, Ray, Summer, spring vessels
  • Ali Nasrabadi, Mohsen Mehrvar, Mohammad Zakiaghl Pages 576-580
    Introduction
    Squash mosaic virus (SqMV) is a seed-borne, beetle transmitted Comovirus, infecting a wide range of cucurbits. This virus has a bipartite positive-strand RNA genome consisting of RNA1 and RNA2, which are separately encapsidated in isometric particles of 28 nm in diameter. The RNA-1-encoded polyprotein yields the viral polymerase, a helicase and a protease, as well as a protease cofactor and the genome-linked viral protein (VPg), while the RNA-2-encoded polyproteins yield the movement protein, large capsid protein and small capsid protein. In this virus, the gene for the LCP (41 kDa) and SCP (22 kDa) was mapped by in vitro translation studies to RNA-2 (contained within the M component), which is in concordance with established information on CPMV and the other comoviruses. While the nucleotide sequence encoding the CP genes in one SqMV isolate (designated here as H-SqMV) has been determined, the nature and extent of sequence divergence between isolates have not been examined.
    Material and
    Methods
    Samples, RT-PCR, cloning and sequencing: In order to identify Squash mosaic virus in squash, melon and watermelon fields in Khorasan Razavi, Southern Khorasan and Mazandaran provinces, 176 plant samples were collected from different areas during 2013 and 2014 growing seasons. The obtained sequences were compared with another source of SqMV in the GenBank. Using DNAMAN version 8 software, a phylogenetic tree was drawn and the nucleotide and amino acid sequence similarity percentages were determined. Total RNA was extracted from fresh leaves using Total RNA Isolation Kit (Denazist, Iran) following the manufacturer’s instructions. The First cDNA strand was synthesized using antisense primer (SqMV-CPR) and Moloney murine leukemia virus (MMuLV) reverse transcriptase (Parstoos, Iran). 3-5 microliters of purified RNA was mixed with reverse transcription mixture (50 mM Tris-HCl pH 8.3, 50 mM KCl, 4 mM MgCl2, 10 mM dithiothreitol, 1 mM of each dNTP, 200 units of MMuLV reverse transcriptase) and incubated at 42 C for 60. The complete length of the coat proteins (CPL, CPS) gene was amplified using specific primers SqMV-CPF by Taq master mix red (Amplicon, Denmark). These primers amplify the complete CPL and CPS genes of SqMV with 1900 bp length. PCR products were run on 1% agarose gel, purified from the gel using the Denazist Gel Extraction Kit (Denazist, Iran). The purified products were ligated into a pTg19 vector (Vivantis, Malaysia) according to the manufacturer's protocol. Plasmids were transformed into Escherichia coli strain DH5a, then Recombinant plasmids were purified from bacterial cells using Plasmid DNA isolation Kit (Denazist, Iran). Finally, the purified recombinant plasmids were subjected to sequencing bidirectional using pUC-M13 universal primers by Macrogen Inc. (Seoul, South Korea). Consensus sequences were verified using the BLAST program in NCBI database.
    Results And Discussion
    Squash mosaic virus (SqMV) is a member of the genus Comovirus in the family Secoviridae. It is a seed-borne and beetle-transmitted virus infecting most plants in the genera Cucurbita and Cucumis. In order to study and determine the distribution of Squash mosaic virus in cucurbit fields of three Iranian provinces (Khorasan Razavi, Southern Khorasan and Mazandaran) a number of 176 samples were collected from these provinces during 2013 and 2014 growing seasons. Ten out of 176 samples were infected by the virus which is indicating that distribution of the virus in Iran is low. Most samples showed symptoms of Squash mosaic virus and the virus was mostly isolated from melons. As cucurbitaceous seeds have been imported from other countries it can be assumed that possibly the virus come alongside infected seeds and then spread by other means such as vectors (Beetle). According to our findings in this study, all Squash mosaic virus isolates divided into two main groups (I and II). Group I is also subdivided into two subgroups A and B. In Group IA, Japanese, melon and Kimble isolates of SqMV are classified with Iranian Jovein and Boshrouyeh 1, 2, 3 isolates. Group IB includes Chinese (CH99 / 211), Arizona, Czech Republic (Tas-1) and one Iranian SqMV isolates (Tabas). In Group II, Iranian SqMV isolates of Khoosf, Birjand and Qayen are located with Spanish isolate (RZ). Based on the comparison of the coat protein gene sequences the highest similarities were 98% and 99.8% between Iranian SqMV isolates and Spanish and Japanese isolates respectively. The lowest similarities were 84.1% and 94% between Iranian Birjand and Boshrouyeh-3 SqMV isolates and Chinese isolates respectively.
    Keywords: Iran, PCR, Squash mosaic virus
  • Fatemeh Abdolahi, Hamid Reza Mohammaddoust¬Chamanabad, Ali Asghari Pages 581-591
    Introduction
    The crop competitive ability is an important and profitable factor for increment impact on the weeds, and decreasing their yield loss. Characteristics such as height, leaf area, growth rate and tillering ability could be effective on competitive ability of cultivar ability. Primary growth rate is important on competitiveness, and any other factors that provides fast establishment of crops growth can be effective too. Thus, utilization of cultivars with height competitiveness ability is one of the considerable strategies for integrated weed managements. Many studies had shown that there are high correlation between crop height and its competitiveness ability. Asef et al (2) reported that tall cultivars reduced weed biomass more than dwarf cultivars due to light intercept and shading. Safahani- langrodi et al (32) in competition condition tall cultivars had high weed tolerance and cause to decrease weed biomass and set seed. There are an important relationship between LAI and weed competition. Hiffle et al. (13) showed cultivars with higher leaf area index had a greater yield stability. Dianat et al. (10) reported that in weed competitive conditions, there are significant difference in the number of tillers among wheat cultivars, while competitor and non-competitor cultivars have most and lowest tiller numbers respectively. Nadery and Ghadiri (25) showed that increasing wild mustard density decreased tiller number and more yield loss in weed competition have caused by decreased number of tillers.
    Materials And Methods
    Experiment was conducted in order to study morphological characteristics and yield of wheat (T. aestivum) cultivars in wild mustard (Sinapis arvensis L.) competition in greenhouse, University of Mohaghegh Ardabili, during 2013-2014. Treatments were 18 wheat cultivars [Karkheh, Alborz, Azadi, Shahpasand, Sepahan, Flat, Ghods, Roshan, Sorkh¬tokhm, Moghan3, Alvand, MS-81-14, Yarvarus, Shahriyar, Golestn, Bam, Niknajad, Karaj3] with and without competition. Treatments were arranged in a factorial experiment based on randomized complete block design with three replications. Each pot was filled with almost 5 kg soil mixture of sand and manure. In each pot 15 wheat seeds along or with wild mustard seeds had sown. In the spring after establishment of wheat seedlings, pots were thinned and 6 wheat seedling in each pots and only one established wild mustard was remained. At tillering stage, tillering numbers in 3 wheat plants were counted. Leaf area was calculated by Ross (28) and Pearcy et al. (27) method at heading stage then leaf area index was estimated by following equation.
    Leaf area= K× (leaf length × maximum leaf width)
    In which: K is constant coefficient (K = 0.75).
    Light penetration within canopy and soil surface was measured by Lux meter version (LX-101). Wheat and wild mustard coverage were assessed visually (34, 23). All trails that involving yield such as (spike number, seeds number per spike and thousand seeds weight), at ripening stage of all wheat in the pots measured and weighted. Data were subjected to ANOVA, and means were separated using Fisher’s Protected LSD test at 0.05 probability (P ≤ 0.05).
    Results
    Analysis showed that wheat cultivars had a significant effect on tillers number, but wild mustard competition had no significant effect (P ≤ 0.05). Means comparison showed that Alvand, Alborz, and Bam cultivars have 8 tillers and Flat only 2 tillers. Also, wheat cultivars at the stem elongation had significant difference on the leaf area but, wild mustard competition effects and interaction effects were did not a significant effects on the mentioned factor (P ≤ 0.05). Between wheat cultivars Alvand had maximum (1.09) and Alborz, Sepahan, Roshan and Flat had minimum leaf area. Wheat coverage at both tillering and stem elongation was different between wheat cultivars. At tillering stage, wheat coverage ranged 7.16 – 53.3, so Alvand and Bam had maximum and Flat and Ghods had lowest amount. Results revealed that, there was significant difference between cultivars light penetration percentage within canopy and soil surface. Wheat yield was influenced under wheat cultivars and wild mustard competition and interaction effects (P ≤ 0.05).
    Conclusion
    It has been hypothesized that increased crop density and spatial distribution and uniformity can increase weed suppression and thereby play an important role in weed management. This study results showed that, the means of light penetration percentage into soil surface on wild mustard competition were %9.82 in weed free and %13.69 in weedy treatments, also biological and economic yield reduced by %13.5 and %26, respectively. Although cultivars recommendation for each specific local area requires too long term studies (in time and site), but results of this study, well documented canopy architecture in view of more tillering potency for Alvand, Bam and Albors cultivars and %50 light penetration reached up to canopy middle for other cultivars such as Karkh, Alborz, Golestn and MS-81-14, which appear to be implemented in integrated weed managements design options.
    Keywords: Environmental pollution, Competitive cultivars, Sustainable production, Weed management
  • Fariba Miaghani, Mohammad Reza Karaminejad Pages 592-604
    Introduction
    This experiment was conducted during 2015-2016 in Karaj to evaluate the performance of some herbicides in view of broad leaf weeds control in new- seeded and established alfalfa. The efficacy of 2,4-DB (Butress( in weed control of alfalfa was compared with commonly used herbicides in alfalfa.
    Materials And Methods
    The experiment was performed in randomized complete-block design with 4 replications and 12 treatments. In new-seeded alfalfa, the treatments were included EPTC (Eradican) 5 L/ha, Metribuzine (Sencor) 750 g/ha, 2,4-DB (Butress) 3 and 3.5 L/ha, Bentazon (Bazagran) 3 L/ha, Imazethapyr (Persuite) 0.5 and 1 L/ha, and without herbicide control treatment. In established alfalfa, the herbicide treatments was the same, but metribuzine and EPTC were not used.
    Results And Discussion
    In new-seeded alfalfa, the best treatments for density decrease of Sisymbrium irio, Descurania sophia and Malcolmia africana were Metribuzine 750 g/ha, Bentazone 3 L/ha, and Imazethapyr 1 L/ha. The best treatments for biomass decrease of Sisymbrium irio were Bentazon (Bazagran) 3 L/ha and Imazethapyr (Persuite) 0.5 and 1 L/h, The best treatments for biomass decrease of Descurania sophia were Bentazon (Bazagran) 3 L/ha, Imazethapyr (Persuite) 0.5 and 1 L/h, and Metribuzine (Sencor) 750 g/h. The best treatments for biomass decrease of Malcolmia africana were Bentazon (Bazagran) 3 L/ha, Imazethapyr (Persuite) 0.5 and 1 L/h, Metribuzine (Sencor) 750 g/h, and 2,4-DB (Butress) 3 and 3.5 L/ha. The best treatments for increasing yield in new-seeded alfalfa during first harvest was Imazethapyr 1 L/ha, during second harvest were Imazethapyr 0.5 and 1 L/ha and during the third harvest were Imazethapyr 0.5 and 1 L/ha, 2,4-DB 3 and 3.5 L/ha, and Bentazon 3 L/ha. Metribuzine 750 g/ha caused phytotoxicity in new-seeded alfalfa during all of the cuttings. In established alfalfa, 2,4-DB 3.5 L/ha was the best herbicide in density reduction of Lactuca, and the best treatment for decrease in Lactuca biomass were 2,4-DB 3.5 L/ha, Imazethapyr (Persuite) 0.5, and 1 L/h. The best treatment for increase in established alfalfa yield at first harvest was Imazethapyr 0.5 and 1 L/ha, at the second harvest were Imazethapyr 1 L/ha, Bentazon 3 L/ha, and 2,4-DB 3.5 L/ha, and at the third harvest were all herbicide treatments except for Metribuzine 750 g/ha and 2,4-DB 3 L/ha.
    Conclusions
    In new-seeded alfalfa, Metribuzine (Sencor) 750 g/ha, Bentazon (Bazagran) 3 L/ha, and Imazethapyr (Persuite) 1 L/ha were the best treatments in decrease of Sisymbrium irio, Descurania sophia and Malcolmia africana density. 2,4-DB (Butress) 3 and 3.5 L/ha was successful only in decrease of density of Malcolmia africana. The efficacy of Bentazon (Bazagran) 3 L/ha and Imazethapyr (Persuite) 1 L/ha was significant in decrease of Sisymbrium irio, Descurania sophia and Malcolmia africana biomass. Alfalfa yield loss was observed in response to Metribuzine 750 g/ha during all three harvests. In established alfalfa, 2,4-DB 3.5 L/ha with the highest ability in Lactuca density decrease and Metribuzine 750 g/ha with complete control of Sonchus were the best treatments. 2,4-DB 3.5 L/ha and Imazethapyr (Persuite) 0.5 and 1 L/h with significant decrease in Lactuca biomass and Metribuzine 750 g/ha with complete control of Sonchus were better treatments. Due to phytotoxicity of Metribuzine 750 g/ha, the yield loss of alfalfa was observed in response to that herbicide during all three cuttings. Therefore, efficacy of Bentazon, 2,4-DB and Imazethapyr depends on their dose and weed species. The same herbicides are recommended to increase alfalfa yield. Metribuzine could control weeds, but it is not recommended for weed control, because alfalfa yield decreased under the effect of this herbicide. In this study, Metribuzine was used as post-emergence. If Metribuzine was used as a soil-applied herbicide, better result can be obtained. It is necessary for supplementary studies for exact results.
    Keywords: Biomass, Broad leaf weeds, Density, Herbicide, Yield
  • Sahar Jannati Ataie, Hemmatollah Pirdashty, Hossein Kazemi, Masoumeh Younesabadi Pages 605-616
    Introduction
    Oil seeds are the second world’s food supply after cereals. These crops are grown primarily for the oil contained in the seeds. The major world sources of edible seed oils are soybeans, sunflowers, canola, cotton and peanuts. Canola is one of the most important plants in the world that has great importance. The plant belongs to the Brassica genus, the botanical family that includes cauliflower and cabbages. Weeds are one of the major problems in canola production that reduce yield and its quality. In general, one of the most important factors in development of management plans is information about the weed’s flora and geographic distribution. Knowledge of weed flora enables one to use the required herbicide and formulate other suitable management strategies. It is also useful in exploiting abundant weeds as a cover crop or pasture and for other economic uses. The geographic information system has the proper use in weed science and management of agricultural information and their analysis. In this study, distribution and flora of the weeds in canola fields of Gorgan Township investigated by Geographic Information System.
    Material and
    Methods
    Crop sampling was conducted during May and June 2014, in 58 canola fields in Gorgan Township (Golestan province) and the weed species were sampled and detected using a W method and by specific formula of density, frequency, uniformity, and abundance of each weed species was calculated. Also, geographic coordinates of fields (latitude, altitude and elevation) were determined by using GPS model Garmin map 60. After collecting data, in order to create a database of weed distribution, the data was transferred from GPS to ArcGIS 9/3.1 software. From all information obtained, consistently a database with location was created and after separation of data based on present or absence of weeds on fields, distribution maps were produced.
    Results And Discussion
    The results showed that there are 35 weed species in canola fields of Gorgan Township and these belonged to 18 families. About 17.1 percent of these species belong to Poaceae and 11.4 percent belongs to Asteraceae and other families, respectively. In general, 77.2 and 22.8 percent of species were annual and perennial weeds, respectively. Also, 80 percent of weeds belong to dicotyledonous and 20 percent to monocotyledonous. The most important species of Poaceae family were Phalaris minor, Avena ludoviciana, Alopecuros sp., Poa annua, Lolium temulentum and Bromus sp. Also, the most important species of Asteraceae were Artemisia annua, Cirsium arvense, Sonchus sp. and Senecio vulgaris. 85.7 percent of weeds reported as broad-leaved weeds and 14.3 percent belong to the narrow leaves. Phalaris minor was the most important weed of narrow leaves and Melilotus officinalis was the most important broad leaf out groups. Among the weeds have been identified, 88.5 percent had photosynthetic cycle of C3 and 11.5 percent were C4. The study results also showed that Phalaris minor had the highest relative dominance among the 35 species and then Melilotus officinalis, Rapistrum rugosum and Avena ludoviciana had 29.4, 28.9 and 23.5 of relative dominance, respectively. To view maps of distribution, based on the abundance of weeds, the three categories 50-100 percent, 30-50 percent and lower than 30 percent were classified. Weeds that have had 50-100 percent frequency were considered as the most important weeds in canola fields of Gorgan. These weeds includes: Phalaris minor and Melilotus officinalis. Weeds that have a frequency between 30-50 percent were considered as medium importance weeds that included Sinapis arvensis, Veronica persica, Avena ludoviciana and Rapistrum rugosum. In final, the weeds with a frequency of less than 30 percent, were placed in the third group as small percentage of surveyed fields. The most important weeds in this group recorded as Artemisia annua, Ranunculus sp., Polygonum convolvulus and Alopecuros sp.
    Conclusion
    In general, weed distribution maps showed that Phalaris minor, Melilotus officinalis, Rapistrum rugosum, Avena ludoviciana, Veronica persica and Sinapis arvensis are present in the most of canola fields in Gorgan region. Therefore, we can be conclude that, observation of high diversity and high dominance of weeds in these fields, may because of similar cropping management by farmers. So, it is recommended as a first step to produce the weed and seed banks maps. On the other hand, we should institutionalize strategies based on sustainable management of weeds.
    Keywords: Distribution maps, Dominate index, Frequency, Geographical information system, Uniformity
  • Ehsan Zeidali, Rooholla Moradi, Fereshteh Darabi, Zeynab Rostami Pages 617-627
    Introduction
    These days, researchers are trying to develop an efficient production technology based on the innovative techniques to increase seedling vigour and plant establishment through physical seed treatments. Seed germination is an important phenomenon in modern agriculture because it is a thread of life of plants that guarantees its survival. Nanotechnology has emerged as an innovative technology for the elaboration and use of new nanomaterials in the industry and many fields of research. It opens up a wide array of opportunities in various fields like medicine, pharmaceuticals, electronics and agriculture. Nanotechnology has the potential to protect plants, monitor plant growth, detect plant and animal diseases, increase global food production, enhance food quality, and reduce waste for “sustainable intensification”(Chandra Rath et al, 2017). Zinc (Zn) is an essential nutrient required by all living organisms. It has been considered as an essential micronutrient for metabolic activities in plants and animals. Zinc has important functions in the synthesis of auxin or indole acetic acid (IAA) from tryptophan as well as in biochemical reactions required for formation of chlorophyll and carbohydrates. It also regulates the functions of stomata by retaining potassium content of protective cells. The crop yield and quality of produce can be affected by deficiency of Zn (Pandey et al., 2006). Zinc oxide (nano-ZnO) is commonly used metal oxide engineered nanoparticle. It is used in a range of applications such as sunscreens and other personal care products, electrodes and biosensors, photocatalysis and solar cells. Seed is an important stage of plant life history. Most invasive plants primarily rely on seedling recruitment for population establishment and persistence. Rapid spread of many invasive plants is frequently correlated with special seed traits. Seed trait variations exist not only among species but also within species. Seed traits variations within a species are essential for seedling establishment at different habitats (Grundy et al., 1996). Germination of various plants has a different response to nanoparticles. Application of nanoparticles that have a positive effect on germination and growth of crop and a negative effect on weed can be useful in weed control.
    Materials And Methods
    In order to study the effect of different concentrations of ZnO on germination characteristics of wild oat and two genotypes of wheat, an experiment was conducted with a factorial arrangement based on completely randomized design with four replications in research laboratory of Ilam University. The experimental treatments were plant genotypes (wild oat and Behrang and Sivand genotypes of wheat) and different concentrations of ZnO (0, 10, 100 and 500 ppm). Germination of seeds was determined by placing 30 seed in a 9-cm-diam Petri dish containing two layers of Whatman No. 1 filter paper, moistened with 5 ml of distilled water or a treatment solution. The treatments of ZnO were applied in Agar complex. After treatment, the dishes were sealed with paraffin tape, and placed in the dark in an incubator at 25 °C. The number of seeds germinated was counted every day. Seedling and radicle length, seedling and radicle dry weight and germination rate were measured. Data were subjected to two-way analysis of variance (ANOVA) and the difference between treatment means was separated using Duncan test. A significance level of 95% was applied by SAS 9.2.
    Results And Discussion
    The results showed that the simple and interaction effects of genotype and ZnO had a significant effect (P ≤ 0.01) on all studied traits. The plumule length of both wheat genotypes was increased to 100 ppm ZnO concentration and then was decreased. The plumule length of oat wild was increased by increasing ZnO concentration. Increase in ZnO concentration to 10 ppm caused a significant increment in the radical length of sivand genotype and wild oat, and the trait was reduced after mentioned concentration. The radical length of behrang genotype was declined as ZnO concentration increased. The applied ZnO treatments caused a significant reduction and increase in plumule dry weight of behrang genotype and wild oat, respectively, whereas they had an insignificant effect on plumule dry weight of sivand genotype. Increased ZnO concentration negatively influenced the plumule dry weight of wild oat and behrang genotype and positively affected the plumule dry weight for sivand genotype. Germination rate and percentage of the both wheat genotypes were not affected by nanoparticle, but, increased ZnO concentration caused a significant increment in these traits in wild oat.
    Conclusion
    Overall, the results illustrated that application of ZnO nanoparticle in wheat agroecosystems can lead to a higher germination rate and growth of wild oat compared to wheat, and is not recommended.
    Keywords: Genotype, Germination rate, Germination index, Plumule, Radicle
  • Heshmatollah Zarinjoub, Mohammad Hossain Gharineh, Javid Gherekhloo, Elham Elahi-Fard Pages 628-638
    Introduction
    The effect of weeds on crop yield has been widely studied and models predicting the relationship between weed abundance and crop yield are useful for simulating yield loss and assisting with developing management guidelines. The herbicide doses recommended by manufacturers are selected to give reliable weed control without crop damage. There is a good potential to apply lower herbicide doses within competitive cropping systems. Wild mustard (Sinapis arvensis L.) is one of the most problematic annual weed in wheat fields of Iran. Herbicides especially the sulfonylurea family are widely used for weed control in wheat. “Iodosulfuron-methyl sodium mesosulfuron methyl mefenpyr-diethyl” is a new sulfonylurea herbicide being developed for postemergence application on weeds in wheat fields of Iran. Environmental and economic costs now require the optimisation of herbicide effects. This study was therefore conducted to evaluate S. arvensis competitive ability with wheat under sprayed conditions.
    Materials And Methods
    A field experiment was carried out at Research Station of Ramin Agriculture and Natural Resources University of Khuzestan in 2015-16. The experiment consisted of four replicates of a split-plot factorial design, with two levels of wheat cultivar (Chamran and Verinac) as the main plot treatments. Other two factors including doses of herbicide (“Iodosulfuron-methyl sodium mesosulfuron methyl mefenpyr-diethyl”) in five levels of 0.2, 0.4, 0.6, 0.8 and 1 of recommended doses and densities of S. arvensis in four levels of 0, 12, 24 and 36 Plants m-2 were implemented in subplots. The competitive effect of the different densities of S. arvensis decreased by increasing doses of “Iodosulfuron-methyl sodium mesosulfuron methyl mefenpyr-diethyl”. Further, same interaction was observed in the standard dose–response curve. The combination of the rectangular hyperbolic model and the standard dose–response curve adequately described the complex effects of herbicide dose and weed competition on wheat biomass. Parametric estimates were used with the model to predict wheat biomass and estimate the doses of “Iodosulfuron-methyl sodium mesosulfuron methyl mefenpyr-diethyl” required to restrict wheat yield loss caused by S. arvensis to an acceptable level.
    Results And Discussion
    The results showed that weed competitivity (β) at no-herbicide treatment was smaller in cv. Chamran than in cv. Verinac, indicating that Chamran was more competitive than Verinac. Herbicide performance, as a result of crop competitivity, was also greater in Chamran with smaller LD50 than Verinac. Using the estimated parameters and the combined model, weed biomass was predicted separately in cvs Chamran and Verinac. The predictions showed that S. arvensis grows better in cv. Verinac than in cv. Chamran. For instance, the model predicted that S. arvensis biomass at 36 S. arvensis plants m-2 with no herbicide treatment was equal to 189.19 g m-2 in cv. Verinac and 171.76 g m-2 in cv. Chamran at selected assessment date, whereas at the same weed density but using half of the recommended dose of “Iodosulfuron-methyl sodium mesosulfuron methyl mefenpyr-diethyl” herbicide, weed biomass was predicted to be approximately 82.74 g m-2 in cv. Verinac and 39.91 g m-2 in cv. Chamran. Using the final model and estimated parameters, crop biomass was predicted. Biomass production of wheat with the utilization only half of the recommended dose of herbicide at the highest assessed density of S. arvensis were predicted to be 569.31 g m-2 in cv. Verinac and 720.49 g m-2 in cv. Chamran. . It is speculated that improved crop competitivity may help to minimize herbicide use. Many studies have found that improvement in crop competitivity was achieved by selecting competitive cultivars. A main aim of the modelling approach to crop:weed competition is to predict crop yield production. Incorporating other factors, i.e. herbicide dose, considerably complicates the prediction process. However, the model presented here provides a valuable tool for predicting the effect of these factors.
    Conclusion
    Results indicates that the standard dose-response model can be modified to a combined model by replacing parameter W0 (the weed biomass at no-herbicide treatment) with the rectangular hyperbolic model. The theoretical outputs of the combined model appear robust and indicate that there are opportunities for reduced herbicide use in the field. Increased crop competitivity by selecting competitive cultivars or increasing crop density may achieve better herbicide performance for crop yield.
    Keywords: Crop_Dose-response_Herbicide dose_Iodosulfuron-methyl sodium + mesosulfuron methyl + mefenpyr-diethyl_Modelling_Weed competition
  • Sedighe Ashtari Pages 639-644
    Introduction
    Bemisia tabaci is highly polyphagous herbivore. This is one of the most important cotton pests throughout the world. Bemisia tabaci causes noticeable damage to quality and quantity of cotton yield. Due to its special habitat, the present efforts to control of the pest have focused on the application of chemical insecticides. It is well established that the overuse and misuse of these compounds can lead to environemntal disasters and development of resistance. Therefore, undertakening research for a safe and environment- compatible method of control has been warranted. In our research, the degree of sensitivity of different life stages of B. tabaci to a juvenile hormone analogue compound and citowett oil was evaluated.
    Materials And Methods
    For this purpose, specimens were collected from contaminated tomato and tobacco flowerpots in the greenhouse of the Faculty of Agriculture at Urmia University. After immersion of leaves in the pesticide solutions, the sensitivity of different life stages was evaluated. The purpose of this test is to determine the range of concentrations of insecticides which would cause 25-75 percent death rate. The main concentrations were calculated by the concentration of preliminary experiments.The control mortality was corrected using Abbott's formula.
    Results And Discussion
    At the termination of experiments the following results were obtained: in all of the treatments, nymph, pupa and egg stages were the most sensitive ones to this compound, respectively, because the juvenile hormone analogue affected the egg and the immature stages but did not affect the adult insects. In the citowett oil treatment nymph, pupa and egg were the most sensitive stages and the adult insect was the most resistant one. The LC50 value of pyriproxyfen after 24 hours for the adult, egg, nymph along with pupa stages (immature stages) were 973.1530, 45.045 and 11.4468 ppm, respectively. The LC50 value of citowett oil after 24 hour for the adult, egg, nymph along with pupa stages were 2243.888, 884.5782 and 623.9682 ppm in the same order. When the basic equation y=a was dotained for each life stage including adult, egg, nymph, pupa, LC25 of pyriproxyfen was counted up with LC25 of citowett oil for each life stage separately, then the pyriproxyfen with citowett oil mixture experiment was performed.The results of this experiment showed a 52.36% mortality rate for the adult, 62.32% response for the egg and 69.19% response for the nymph and pupa stages. These experiments revealed that the enhacement of pyriproxyfen toxicity when mixed with citowett oil. It can be argued that citowett oil has a synergistic effect on pyriproxyfen.In similar research the rate of LC50 pyriproxyfen for egg was 51 ppm and for the first instar nymphs was 18 ppm. This researchres also elucidated that first instar nymphs is the most sensitive of development stages and pupae have more tolerance in contrast of nymphs. Egg sensitivity is less than the other stages due to chorion layer. In a similar study Bemisia tabaci immature stages were more sensitive to pyriproxyfen than the other stages and it was concluded that the enfulence of pyriproxyfen even at low levels was effective on the immature stages.The LC50 of Citowett oil for adult, egg and immature stages of whitefly were reported 2580, 1310 and 250 ppm, respectively, that results of this study were different to the current researchdue to differences in insect biotype and historyof pest. To evaluate the effect of pyriproxyfen and oil mixture, LC25 of these compounds in the different stages were mixed.The mortality rate caused by mixing pyriproxyfen and citowett oil was further
    Conclusions
    These experiments demonstrated that because of the cheap price of citowett oil, in contrast to that of pyriproxyfen, a mixture of these compounds led to better control of Bemisia tabaci and is more economical.
    Keywords: Bemisia tabaci, Bioassay, Citowett oil, Synergistic effect
  • Majid Mahmoudi, Hossein Pezhman, Majid Mirab-Balou Pages 645-652
    Introduction
    Western flower thrips, Frankliniella occidentalis (Pergande) is a serious pest of fruit crops in flowering stage worldwide. Many researches have been studied different methods of western flower thrips control. Two control methods including pesticide application and the use of colored sticky traps are commonly used by farmers due to the ease of use and low running costs. Chemical control is known as the main tool in controlling of this pest. In recent decades, mixing several kinds of pesticides by farmers has been become common strategy which seems to be due to their synergistic effects and decreasing of pest resistance one. The current study was done to detect the best color sticky trap in monitoring and to determine the most effective pesticide in controlling western flower thrips.
    Materials And Methods
    In the current study, the pest attraction rate by 3 sticky color traps (Blue, Yellow, White) and efficacy of five pesticides were investigated against western flower thrips in two separately randomized complete block design in the apple orchard around Shiraz city. The treatments included: deltametrin imidacloprid, acetamiprid, antifeedant, azadirachtin and oxydemeton methyl. Mortality percent of insects in different treatments was calculated using the Henderson-Tilton formula. Before conducting the experiment, trees was not treated by any pesticides for one year. Each trap was hung in the middle of the trees´ canopy at about 1.5 meter height from the ground. Sticky cards (10 x 25 cm) were visited weekly to record the number of the captured western flower thrips. Each trap was replaced with new one weekly. Number of western flower thrips was analyzed through one-way analysis of variance (ANOVA) using the SPSS version 9. The significant differences among means were compared using the Duncan's multiple range test at 95% confidence interval whenever treatment effects were significant.
    Results And Discussion
    Analysis of variance showed that there were significant differences among treatments after 14 days post-treatment (F5, 10 = 6.51, P = 0.006). Mean comparisons showed that treatments deltametrin imidacloprid, acetamiprid and antifeedant had significant difference with control. Pesticide efficacies based on Henderson-Tilton formula at 14 days post-treatment showed that acetamiprid provided the best control (83.3%) of F. occidentalis, followed by deltametrin imidacloprid (77.7%) and antifeedant (70.1%). Effectiveness of acetamiprid, which is a systemic pesticide and belongs to neonicotinoids, against a wide range of insect pests has been reported by many researchers. The treatment oxydemeton methyl caused low mortality (less than 30%) in F. occidentalis. The reason of that may be related to resistance of this insect to oxydemeton methyl. This pesticide is older than other tested compounds and has been used by farmers against fruit pests from long time ago. Further studies are needed to confirm these findings like bioassay of this pesticide. In addition, some researchers have shown that inappropriate application of chemical compounds resulted in high level and widespread resistance of thrips to chemicals. Results of color traps showed that blue traps attracted significantly more thrips than other colors in the all sampling dates. On average, the blue, yellow and white traps captured 34.31 ± 13.85, 12.56 ± 4.78 and 4.87 ± 1.83 thrips respectively. In general, there are many studies have been conducted to determine the effect of color traps on thrips. Some studies have reported that thrips are attracted to blue, while the others have reported that yellow is more attractive for them. There are evidences that F. schultzei is also caught by red color. With regard to color preference of western flower thrips, there are many disagreements among researchers. Different researchers have stated different reasons for these contradictions that the most important are the availability of food sources, thrips density, environmental conditions and the duration time of the experiment carrying out.
    Conclusion
    The results of the present study indicated that a remarkable ability of blue traps in catching of the western flower thrip. In addition, results showed that acetamiprid, deltametrin imidacloprid and antifeedant could considerably reduce the population density of F. occidentalis. Although the pesticides acetamiprid, deltametrin and imidacloprid have been recommended in IPM programs, in organic farming, it is approved that application of pesticides are much more limited. It seems that antifeedant is environment-friendly and can be recommended in organic farming. However, more research is needed to explore the impact of this compound on other agricultural systems. In conclusion, blue sticky color and deltametrin imidacloprid, acetamiprid and antifeedant could be useful in IPM planes against western flower thrips.
    Keywords: Blue sticky trap, Confidor, Deltametrin, Mospilan, Western flower thrip
  • Amin Radmard Titkanlo, Saeed Nasrolanejad, Rahim Ahmadvand, Abas Rezai Asl, Farveh Sadat Mostafavie Neyshabori Pages 653-661
    Introduction
    Potato virus x (PVX) is one of the most devastating viruses in the fields of tobacco and no effective method to control the virus has been provided yet. Magnetism is known as one of the environmental stresses that can directly or indirectly affect the plants, especially plants under stress. The magnetic fields can have beneficial affects plants.
    Materials And Methods
    In the present study to investigate the effects of electromagnetic fields on PVX control, an experiment based on completely randomized design with eleven treatments (10, 50 and 90 mT in a period of 60, 90 and 120 minutes on tobacco seedlings infected with the virus and two control, and the other one is free from analog infected with the virus) in tobacco seedlings carried on six repeats.. After inoculation at the four-leaf stage and after 14 days, the amount of turbidity virus infection rate is calculated and then ensure equality of tobacco seedlings, where the electromagnetic device. 30 days after applying an electromagnetic field analysis of the results of ELISA test two samples were tested with antisera Chndhmsanh of PVX. The amount of salicylic acid and the enzyme phenylalanine ammonia in systemic acquired resistance and plant defense mechanisms are involved, the treatments were measured, for evaluation of HPLC as salicylic acid and phenylalanine ammonia-based assessment of trans-cinnamic acid was used.
    Results And Discussion
    Statistical analysis ELISA test results revealed that there is a significant difference between treatments 0/05. So that the treatment was a no pollution treatment and 11 who were infected but had not been exposed to the electromagnetic field had a significant difference compared to other treatments, among the treatments that were exposed to the electromagnetic field treatment 8 (100 mT, 120 minutes) showed the lowest OD in ELISA and later treatment 7 (50 mT and 60 minutes) was the lowest OD, the two treatments were observed in less than two OD. If the treatment number 11, OD (2/85) and in pollution-free treatment that was an OD (0/35) was observed. The OD also in other treatments were not exposed between 2.00 to 2.46 were visible. The results showed that the treatment 11 (infected control) actually infected treatment that has not been exposed, and treatment 8 is the most desirable treatment for a reduction in the OD, the difference in the OD are available 0/98. The results suggest that the electromagnetic field decreases the amount of OD in tobacco seedlings are infected with PVX. Researchers said electromagnetic field growth rate and the number of spores grown in three species are affected. In another study, it was found that the impact on dry and wet mycorrhiza. The electromagnetic field decreases witche's broom disease infected lemon trees that were probably due to the decline phytoplasmas in plant tissues. Another study on the antibacterial effects of electromagnetic fields on Serratia marcescens was conducted, which resulted in the inhibition of bacterial growth. The results of salicylic acid and PAL determine the tobacco crop treatments, there are significant differences in the level of 0/05. So that treatment (7) (50 mT, 60 min) the highest salicylic acid and treatment 1 (control non-infected) showed the lowest rates. Also, reviews PAL treatment and treatment (7) most (1) (see non-polluting) had the lowest. In fact, with the arrival of the pathogen to the host salicylic acid and phenylalanine ammonia will increase. But the electromagnetic stress in some treatments of both traits, from infected plants, should take over. However, some treatments less than 11 treatments (infection control) is (but treatment Salicylic acid (4) was less than healthy plant). Interestingly, in both treatments was the highest for both traits in treatments of 7, 6 and 5, respectively. Pre-plant treatments with salicylic acid caused a significant increase in the PAL activity, which indicates the role of these enzymes in plant defense mechanism, the researchers concluded that electromagnetic frequency is very low, possibly because of the resistance of tobacco to TMV and increased Ca2 signaling pathway involving PAL and ODC hormones in plants.
    Conclusions
    Comparing results of ELISA plants that had been under different electromagnetic fields the survey showed that 11 infected untreated control treatment without exposure possession was the highest infection. While treatment 8 (100 mT and 120 minutes) and 7 (50 mT for 60 minutes) showed the least amount of turbidity virus. Also in measuring hormone salicylic acid and PAL significant difference between treatments in both studies showed that treatment trait No. 7 in both traits were seen as the highest value. These results suggest a positive effect in reducing turbidity electromagnetic virus, an increase of salicylic acid and phenylalanine ammonia enzymes, hormones and enzymes that are involved in plant defense mechanisms as well.
    Keywords: Electromagnetic, Systemic acquired resistance, PVX
  • Sara Parande, Seyed Vahid Eslami, Majid Jamialahmadi Pages 662-675
    Introduction
    Light is a vital component for photosynthesis and plays a significant role in the competitive ability of plants. The nitrogen response of competing plants may be affected by radiation availability and maximum potential growth rate, which determine N requirements. Shading reduces the light intensity, which leads to changes in the morphology, physiology, biomass, grain yield and quality of crops. Finally, shading stress delays flowering and decreases biomass and grain yield. Because photosynthesis is associated with dry matter accumulation, and light is known to limit carbon accumulation and nitrogen content, understanding these processes in weeds may provide insight as to their effects on crop production, help to predict their occurrence, and ultimately provide the needed information for their management.
    Materials And Methods
    In order to evaluate foxtail millet competition with pigweed at different levels of radiation and nitrogen, two separate experiments in split plot arranged in randomized complete block design with three replications were conducted in 2015 at the Research Farm of Birjand University. Texturally, the soil was loam, with 8.16 pH, 0.03% total N, 12 ppm available P and 250 ppm available K. The experiment was laid out in a split-plot design with three replications having three shade levels (0, 41 and 75% shade) in main plot and three pigweed density (0, 12 and 24 plant per meter square) in subplots in two separate experiments, one under nitrogen application and the other without it. In 0% shade treatment, sunlight was allowed to fall over the millet and pigweed without any barrier. In 41% and 75% treatments, the light levels in the form of PAR were reduced using sheds nets. At the end of growth stage millet traits including plant height, spike length, peduncle length, stem diameter, number of leaf, lodging, grain yield and biomass and pigweed traits such as plant height, number of Lateral branches, number of seed per plant and biomass were measured. Data analyses were performed using two-way analysis of variance (ANOVA) by SAS 9.1 software. Means of treatments were compared between nitrogen, shade treatments and pigweed densities according to protected least significance differences (LSD) test at the 5% level.
    Results And Discussion
    Nitrogen had a significant effect on all millet traits except for peduncle length and biomass and also on pigweed height. Nitrogen led to significant increase in plant height, lodging percentage, number of leaf, spike length and grain yield of millet and also pigweed height. Shading had a significant (P
    Conclusions
    This research provides information on how pigweed and foxtail millet respond to reduced radiation and low nitrogen environments. Under low-radiation environments, pigweed produced less seeds that would limit the replenishment of the next year’s seed bank. Therefore, production practices such as narrow rows that reduce radiation availability would be helpful in reducing pigweed infestations. Once a dense canopy is formed, vegetative growth and the reproductive potential of pigweed seedlings are severely restricted. A uniform dense crop canopy is of paramount importance in developing an integrated approach to control this weed because any gaps in the canopy allowing light penetration will result in a rapid weed growth and prolific seed production. Further, nitrogen deficiency seems to decrease weed competition ability and seed production leading to less infestations.
    Keywords: Interference, Morphological traits, Shading, Yield
  • Azam Hatami Hampa, Abdollah Javanmard, Mohammad Taghi Elebrahim, Omid Sofalian Pages 676-689
    Introduction
    The loss of crop yield due to weeds is enormous. Potential yield reductions caused by uncontrolled weed growth throughout a growing season have an estimated range of 45-95%, depending on ecological and climatic conditions. Overusing synthetic herbicides may affect the environmental, human health and food. Furthermore, increasing use of herbicides has resulted in a dramatic increment in the herbicide resistance among weeds, and over 307 weed resistant biotype belonging to 183 species (110 dicots and 73 monocots) have been identified worldwide. Cultivating crops with allelopathic potential can reduce the dependency on synthetic herbicides and increase crop yields. Sorghum (Sorghum bicolor L.) has been reported as one of the most allelopathic crops extensively used as cover and smother crops and also incorporated in the soil for weed suppression. Moreover, Russian knapweed (Acroptilon repens L.) has been shown to produce phytotoxic compounds and plant growth inhibitors, which may contribute to its competitive behavior. The phenomenon of allelopathy has been suggested to be one of the possible alternatives for achieving sustainable weed management.
    Materials And Methods
    In order to evaluate the allelopathic effects of sorghum (Sorghum bicolor L.) and Russian knapweed (Acroptilon repens L.) extract on seed germination indices and enzymatic activity of wheat (Triticum aestivum L.), sugar beet (Beta vulgaris L.), common lambsquarters (Chenopodium album L.) and redroot pigweed (Amaranthus retroflexus L.), an experiment was conducted as factorial experiment based on randomized completely design with three replications in Faculty of Agriculture, University of Maragheh in 2016. The investigated factors were four crops (wheat, sugar beet, common lambsquarters and redroot pigweed), shoot aqueous extract (sorghum and Russian Knapweed) and aqueous extract concentrations at 0 (control), 5, 10 and 20% (m/v). Sorghum and Russian knapweed crops were collected during July 2016. The plants were taken to the laboratory and kept fresh in a refrigerator. In addition, Kato-Noguchi et al., (17) method was followed for extraction. Samples of the above-ground tissues (stems and leaves) of sorghum and Russian knapweed were washed thoroughly with tap water and rinsed with distilled water. They were clipped and then passed through a 1 mm screen before storage in a refrigerator at 2 ℃. Each 50, 100 and 200 g samples was extracted by soaking it in 1 L of distilled water at 24 ℃ during 24 h in a shaker. All extracts were filtered through two layers of cheese cloth to remove fibers. Distilled water was also considered as the control treatment.
    Results And Discussion
    Results indicated that percentage and rate of germination, radicle and plumule length, radicle dry weight, plumule dry weight, seedling dry weight and vigor length index of all crops decreased significantly by increasing aqueous extract concentration of sorghum and knapweed. These results are in agreement with those previously reported that the degree of inhibition increased by increasing extract concentration. Using Russian knapweed aqueous extract, germination percentage was 12.62 percent greater than sorghum aqueous extract. Moreover, inhibitory effect of sorghum aqueous extract on germination rate loss was higher than that of aqueous extract of Russian knapweed. As to field crops, inhibitory effect of sorghum and Russian knapweed extract on sugar beet was higher than wheat. Moreover, the effect of sorghum and knapweed extract on radicle, plumule and seedling fresh weight loss of redroot pigweed and common lambsquarters (weeds) was greater as compared with that on field crops (wheat and sugar beet). Increasing concentration of sorghum extract decreased seed vigor indices of common lambsquarters and redroot pigweed by 83.36 and 87.15% relative to control, respectively. Activity of peroxidase and polyphenoloxidase enzymes was reduced and increased, respectively, as a result of an increment in extract concentration. Batish et al. (7) have demonstrated that parthenin (Parthenium hysterophorus) impairs mung bean growth by affecting respiration, protein content and activities of protease and peroxidase enzymes. The minimum value of plumule and seedling length was observed for redroot pigweed and common lambsquarters weeds with application of 20% aqueous extract of sorghum and Russian knapweed. The values of weed tolerance index (WTI) revealed that redroot pigweed and common lambsquarters were more sensitive to aqueous extract of sorghum and Russian knapweed. The WTI combines several individual measured parameters and ranges between 0 and 1. In this case, a low WTI indicates a high susceptibility to biotic or abiotic stress originated from crop extracts.
    Conclusions
    Our results showed that aqueous extracts of sorghum and Russian knapweed had an inhibitory effect on seed germination indices of wheat, sugar beet, common lambsquarters and redroot pigweed. It can be also concluded that sorghum and Russian knapweed possess weed-suppressing ability and seem to be useful for developing natural herbicides.
    Keywords: Common lambsquarters, Polyphenoloxidase, Redroot pigweed, Seed vigor, Weed tolerance index
  • Marjan Diayanat Pages 690-699
    Introduction
    Slender amaranth (Amaranthus viridis L.) and prostrate pigweed (Amaranthus blitoides S. Watson) are two common weeds in vegetables and summer crop fields of Iran. The two Amaranthus species have all the attributes required by ecologically successful annual weeds: rapid growth, early reproduction and continuous seed production. Knowledge of the germination requirements of these weeds will helps determine the proper conditions for germination and emergence and allow better management of them. Water and temperature are determining factors for seed germination of weed. Both factors can, separately or jointly, affect the germination percentage and germination rate. Water stress is one of the main constraints on plant growth and the most common environmental stresses around the world. Water stress affects the different aspects of plant growth and causes reduction and delay in seed germination. Seed germination of all plant species requires a minimum of water to be absorbed and swelled and that is why osmotic potential should not be less than a certain amount.
    Materials And Methods
    Seeds were harvested from vegetable fields of Karaj. For breaking dormancy, seeds were treated with concentrated sulfuric acid for two minutes. Two experiments were conducted at Islamic Azad University, Science and Research Branch, Ecology lab, in 2016. First experiment was based on completely randomized design with 4 replications .The seeds were treated with different temperatures (5, 10, 15, 20, 25, 30, 35, 40 and 45oC). Germination percentage and germination rate were measured and seed were considered to have germinated with the emergence of the radical. Intersected lines model is used to determine the cardinal temperature. Second experiment was conducted to determine the effects of simulated dry conditions (use PEG) and temperature on seed germination of slender amaranth and prostrate pigweed. Exposure to polyethylene glycol (PEG-6000) solutions has been effectively used to mimic drought stress with limited metabolic interferences as those associated to the use of low molecular weight. Over a 21d period, germination was studied in 5, 10, 15, 20, 25, 30, 35, 40 and 45°C constant temperatures and water potentials of 0, -0.2, -.04, -.06, -0.8 and -1.0 MPa. The number of 25 seeds were placed into petri dishes, then 10 ml of prepared drought solution was added to each petri dishe. Petri dishes, then, were placed in germinator in circadian alternation of 12 h light and 12 h darkness, under 9 temperatures and a relative humidity of 65 %. Data were statistically analyzed using analyses of variance in the SAS 9:1 software. Probabilities of significance were used to indicate significance among treatments and interaction effects. FLSD (p
    Keywords: Cardinal temperature, Intersected-lines Model, Sigmoid model, Weed
  • Y. Mohammad Alian, Seyedeh Najmeh Banihashemian, M. Golmohammadi, S.M. Banihashemian, S. Bashiri Pages 700-705
    Introduction
    Citrus nematode is one of the most important damaging nematodes of citrus trees, spreading widely in most areas under citrus planting causing dieback, the gradual decline of trees and crop decrease in citrus orchards. Eighty citrus cultivars and species are sensitive to this nematode. From other nematode hosts, we can refer to olive, fig, medlar, persimmon, pear and grapevine. Surveys Full filled in Mazandaran province is indicative of the widespread of this nematode in citrus horticulture and the level of infection in some samples is so high, thus it is necessary to use different ways of controlling this parasite.
    Materials And Methods
    This research was carried out for 2 successive years and the reaction of sin citrus rootstocks including Citromelo, Poncirus, Sour Orange, Bakraee, Rough lemon and Off-type to citrus nematode under controlled conditions in the greenhouse was evaluated. Three months years old plants of this rootstock Were planted in completely random design with 5 replications in pots containing the population of 40 larvae per cubic centimeter of soil and after six months, the level of infection of roots was investigated and then the most tolerable rootstock for nematode was introduced on the basis of the least population of young females and adult females injected in one gram of root volume.
    Results And Discussion
    Experiment results on the basis of LSD test in two successive years indicated that there is a meaningful statistical difference between Citrumelo and poncirus Poncirus with the least population of nematode of adult female on the root and other treatments the results show that sour orange and off-type rootstocks are the most sensitive to citrus nematode, poncirus Poncirus and Citrumelo are the most tolerable to nematode Bakraee and Rough lemon are in the biotype group with average tolerance (relatively sensitive) to citrus nematode. Purpose of this research is to assess the sensitivity level of six citrus rootstocks including Citromelo, Poncirus, Sour Orange, Bakraee, Rough lemon and Off-type some of these rootstocks are common citrus rootstocks in the North and south citrus regions of the present time, therefore it is necessary to choose appropriate rootstock. In addition to it, another purpose (aim) of this research is to assess tolerance of new off-type biotype, produced from citrus breeding programs, to citrus nematode under greenhouse conditions in comparison with Citromelo, Poncirus, Sour Orange, Bakraee and Rough lemon which are common citrus rootstock in the North and South provinces of the country. Bakraee is one of the natural types of citrus used in citrus regions of Fars, Hormozgan and Kerman as rootstock of mandarin and orange cultivars for many years. Introductory surveys concerning Bakraee tolerance to coldness, the rot of crown and root, and diseases such as Tristeza, Exocortis and Cachexia were carried out but its tolerance to citrus nematode has not surveyed yet. Recent molecular surveys showed Bakraee relationship with Rough lemon beside, because of appearing unknown disease of citrus trees decline on Bakraee rootstock from the beginning of 1389 in Jiroft mountainous regions, doing etiology studies and investigating its tolerance to disease factors such as citrus nematode is of great importance. Since this nematode is soil parasite and can live in the depth of soil, its chemical control is very difficult. Despite the fact that one of the control methods of it is soil sterilization before citrus planting, but because of increasing environmental risks and bad effects on human health, it is recommended that resistant rootstocks such as Poncirus should be planted in the nematode soil. Also, it is necessary to control plants in selling time from the aspect of infection and, if necessary, to sterilize infected plants in order to prevent infection spread and build healthy orchards. Therefore regarding the fact that rootstocks of Poncirus and Citromelo are resistant to Tristeza and gummosis and identifying their resistance to citrus nematode, so planting of these rootstocks in the North of the country can be effective in managing citrus nematode in infected areas. In fact, investigating resistance of common rootstocks in the region and having access to resistance sources can be regarded as a method for sanitation of plants and as a result for controlling this nematode and increasing yield in the region. Also, the results of this survey can help horticulturists to introduce and produce appropriate rootstocks in the south of the country.
    Keywords: Citromelo, Nematode, Poncirus, Rough lemon, Sour orange