Evaluation of defoliation on leaf water relations, chlorophyll content, and grain yield of triticale (x triticosecale wittmack) genotypes under water stress

Document Type: Full Article


1 College of Agriculture and Natural Resources of Darab, Shiraz University, I. R. Iran

2 Department of Crop Production and Plant Breeding, College of Agriculture, Shiraz University, Shiraz, I. R.Iran


Optimizing the source size and its utilization by the sink is one of the main factors enhancing the yield potential and decreasing water demand in crops when exposed to drought. To investigate the effect of defoliation on leaf water relations, chlorophyll content and yield components of five triticale genotypes including Sanabad, Juanillo, ET-83-3, ET-84-5 and ET-84-8 under well-watered (100% FC) and water stress (50% FC) conditions, a controlled experiment was carried out at Shiraz University in 2013. The results showed that ET-84-8 and Sanabad genotypes had higher chlorophyll content (ranged from 49.1 to 54.6 SPAD unit) under water stress. Among the triticale cultivars, water stress caused 21 to 42% decline in rate of water loss (RWL) In all genotypes except ET-83-3 and Juanillo, the excised leaf water retention (ELWR) was slowly decreased under water stress conditions. In all triticale genotypes except ET-84-8, water stress declined main shoot yield 21-22%, while in ET-84-8 was only 9%. Interestingly, in ET-84-8, grain number per spike was not affected by moisture regimes. Sanabad cultivar, with 2.57 g/g had the highest initial water content (IWC) at defoliation of all leaves except the flag leaf and penultimate leaf treatment under water stress. Under defoliation and water stress, ET-84-8 and Sanabad genotypes showed a greater 100-grain weight ranged from 3.60 to 3.74 g. It was concluded that triticale cultivars were more sink-limited especially under water stress, and source restriction by defoliation which had less effects on main shoot yield could be used as a useful tool for lowering water consumption during grain filling.


Main Subjects

Article Title [Persian]

ارزیابی روابط آبی برگ، محتوای کلروفیل و عملکرد دانه ژنوتیپ های تریتیکاله در شرایط کمآبی و برگزدایی

Authors [Persian]

  • احسان بیژن زاده 1
  • یحیی امام 2
1 دانشکده کشاورزی و منابع طبیعی داراب، دانشگاه شیراز، داراب ، ج. ا. ایران
2 گروه زراعت و اصلاح نباتات، دانشکده کشاورزی، دانشگاه شیراز، شیراز، ج. ا. ایران.
Abstract [Persian]

بهینه کردن اندازه مبدا و استفاده مواد پروده آن در مقصد یکی از عوامل مهم در افزایش پتانسیل عملکرد و کاهش تقاضای آب در گیاهان زراعی در شرایط تنش خشکی می باشد. بمنظور بررسی اثرات برگ زدایی بر روابط آبی برگ پنج ژنوتیپ تریتیکاله شامل سناباد، جوانیلو، 3-83ET- ،5-84ET- و 8-84ET- در شرایط آبیاری مطلوب (100 درصد ظرفیت مزرعه) و تنش کم آبی (50 درصد ظرفیت مزرعه)، آزمایشی گلخانه ای در سال 1392 در دانشگاه شیراز به اجرا در آمد. نتایج نشان داد که رقم 8-84ET- و سناباد محتوی کلروفیل بالاتری (در دامنه از 1/49 تا 6/54 واحد اسپد) در شرایط تنش کم آبی داشتند. در بین ارقام تریتیکاله تنش کم آبی باعث کاهش 21 تا 42 درصدی در سرعت از دست دادن آب برگ (RWL) شد. در همه ارقام به غیر از 3-83ET- و جوانیلو مقدار آب نگهداری شده در برگ (ELWR) به آرامی در شرایط تنش کم آبی کاهش یافت. در همه ارقام تریتیکاله به غیر از 8-84ET، تنش کم آبی عملکرد ساقه اصلی را بین 21 تا 22% کاهش داد در حالی که این کاهش در رقم 8-84ET-  تنها 9%  بود. جالب اینکه تعداد دانه در سنبله در رقم 8-84 ET- تحت تاثیر رژیم رطوبتی قرار نگرفت. همچنین وقتی همه برگ ها به غیر از برگ پرچم و برگ ماقبل پرچم حذف شدند، رقم سناباد با 57/2 گرم بر گرم دارای مقدار آب اولیه برگ (IWC) زیادتری بود. در شرایط تنش کم آبی و برگ زدایی، ارقام 8-84ET- و سناباد وزن هزار دانه بیشتری (در دامنه ای از 6/3 تا 74/3 گرم) داشتند. می توان نتیجه گرفت که ارقام تریتیکاله بویژه در شرایط کم آبی مقصد- محدود بوده و اعمال محدودیت مبدا از راه برگزدایی تاثیر کمتری در عملکرد دانه داشت، که این موضوع می تواند به عنوان ابزاری سودمند در کاهش آب مصرفی در دوره پر شدن دانه مورد استفاده قرار گیرد.

Keywords [Persian]

  • واژگان کلیدی: مقدار کلروفیل
  • مقدار آب اولیه برگ
  • سرعت از دست دادن آب برگ
  • اندازه مبدا
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