عملکرد پتانسیل گندم آبی (triticum aestivum l.) و تاثیر صفات گیاهی بر آن در شرایط اقلیم کنونی و آینده در سراسر ایران

اصلاح ارقام جدید در جهت افزایش عملکرد در واحد سطح همواره یکی از راهکارهای افزایش تولید محصولات کشاورزی بوده است. شناسایی صفات گیاهی تاثیرگذار بر عملکرد می‏تواند روند اصلاح ارقام جدید را تسریع بخشد. هدف از این مطالعه، شناسایی صفات گیاهی کلیدی در جهت افزایش عملکرد گندم آبی (triticum aestivum l.) در مناطق تولید گندم در سراسر ایران بود. این مطالعه به‌کمک شبیه‏سازی تاثیر صفات مختلف گیاهی بر عملکرد پتانسیل گندم آبی، توسط مدل ssmwheat برای شرایط اقلیم کنونی و آینده انجام شد. برای این منظور از پروتکل پروژه اطلس خلا عملکرد، موسوم به پروتکل گیگا، در جهت شناسایی پهنه‏های اقلیمی و همچنین شناسایی ایستگاه‏های هواشناسی مهم واقع در مناطق تولید گندم آبی در کشور استفاده شد. برای پیش‏بینی شرایط اقلیم آینده از روش دلتا و سناریوی انتشار rcp4.5 برای سال 2055 استفاده شد. در این مطالعه اثر کاهش و افزایش طول دوره شروع پنجه‏دهی تا شروع ساقه رفتن، طول دوره پر شدن دانه، کارایی استفاده از تشعشع و توسعه سطح برگ بر عملکرد پتانسیل گندم آبی بررسی شد. میزان تاثیر افزایش طول دوره پر شدن دانه به‌عنوان صفت کلیدی بر عملکرد پتانسیل برای اقلیم کنونی 15.3 درصد و برای اقلیم آینده 16.8 درصد بود. افزایش کارایی استفاده از تشعشع در سطح کشور باعث افزایش 14.7 درصدی عملکرد برای اقلیم کنونی و 13.7 درصد برای اقلیم آینده شد. اثر افزایش کارایی استفاده از تشعشع بر عملکرد پتانسیل، در مناطق گرم (gdd>6000) بیشتر از مناطق خنک بود. افزایش طول دوره شروع پنجه‏زنی تا شروع ساقه رفتن، صفتی بود که فقط در مناطق گرم منجر به افزایش عملکرد شد و اثر آن در مناطق خنک یا ناچیز بود و یا کاهش عملکرد پتانسیل را در پی داشت. نتایج این مطالعه می‏تواند در انتخاب صفات کلیدی برای افزایش عملکرد و تسریع تولید ارقام پرمحصول در مناطق مختلف گندم آبی به کار گرفته شوند.

Irrigated Wheat (Triticum aestivum L.) Traits Effects on Potential Yield under Current and Future Climates in Iran

IntroductionWheat (Triticum aestivum L.) known as a main crop in Iran. It is the main source of calories and protein which directly provides 37 percent of the food calories and 40 percent of daily protein for people in Iran. Breeding to produce new cultivars is always an important way to increase crops yield. New cultivars breeding is a very complex process because there is an interaction between climate and genotype and the time is limited to produce new cultivars adapted to new climates. The target trait identification can accelerate new cultivar breeding process. The objectives of this study were to explore the potential benefit of irrigated wheat traits over the country to increase the yield. Materials and MethodsThis study was performed at potential yield simulation using SSMWheat crop model to evaluate different traits impact on irrigated wheat potential yield in Iran. For this purpose, the protocol presented by Global Yield Gape Analysis (GYGA) was used to identify the same climate zones and the main weather stations for irrigated wheat in Iran. The potential yield of irrigated wheat was simulated by SSMiCrop model for the area covered by each main weather stations. The average potential yield was calculated at the country level by scaling up the simulated results within the area covered by weather stations using the GYGA protocol. All the simulations and calculations were done for existing cultivars and for the cultivars with desired plant traits, identified in this study, under current and future climates. The effect of desired plant on potential yield was quantified by comparison of simulation results between existing cultivars and the cultivars with desired plan traits. Future climate (2055) scenario were created for the sites using the baseline 19862005 and the projections for delta mean air temperature (and precipitation) which is the difference between the future air temperature (and precipitation) and baseline air temperature (and precipitation). Deltas of air temperature and precipitation were obtained from the international panel on climate change report which it used 42 GCM model outputs under RCP4.5 climate change scenario to calculate them. Results and DiscussionsIn this study, the effect of increasing and decreasing of biological days from tillering to stem elongation, biological days from anthesis to philological maturity, the rate of canopy development and radiation use efficiency on irrigated wheat potential yield were evaluated. Increasing biological days from anthesis to philological maturity increased the potential yield in all the regions under current (15.3 %) and future climates (16.8%). The potential yield gain from increasing radiation use efficiency was 14.7% under current climate and 13.7% under future climate. The effect of decreasing biological days from tillering to stem elongation, biological days from anthesis to philological maturity, the rate of canopy development and radiation use efficiency on the potential yield were negative. Monpara (2011) reported that increasing duration of grain filling period was an effective trait to increase wheat yield in India. Yang et al. (2008) demonstrated that the yield of rice increased with increasing cumulative radiation receiving during grain filling period. There was positive correlation between cumulative radiation receiving during grain filling and grain filling duration. With longer stay green duration, the potential yield of wheat increased thereby raising photosynthesis during wheat grain filling period (Spano et al., 2003).ConclusionIncreasing radiation use efficiency positive effect on potential yield in the regions with warmer climate was higher than the region with lower average temperature over the year. Increasing radiation use efficiency had negative effect on potential yield in some cooler regions. Increasing biological days from tillering to stem elongation just had positive effect on potential yield in the region with warmer climate and its effect was negative in the regions with cool climate. The faster canopy development had no significant effect on potential yield.