بررسی کارآیی مصرف و کودپذیری آهن در ژنوتیپ های مختلف گندم

شناخت و تمایز ارقام عنصرکارآ و کودپذیر از یکدیگر برای کاشت در سیستم های کشاورزی ارگانیک و سیستم های کشاورزی پر نهاده ضروری است. در کشاورزی ارگانیک ژنوتیپ های عنصر کارآ به دلیل کودپذیری پایین در اولویت انتخاب قرار دارند، در حالی که در کشاورزی پر نهاده و پر تولید، ارقام پرمحصول انتخابی، معمولا کودپذیری بالایی دارند. به منظور شناخت و تمایز ژنوتیپ های گندم آهن کارا و کودپذیر از یکدیگر، آزمایشی به صورت فاکتوریل در قالب طرح بلوک های کامل تصادفی با سه تکرار در ایستگاه تحقیقات کشاورزی و منابع طبیعی خراسان رضوی (طرق) طی سال های91-1389 انجام شد. تیمارهای آزمایش شامل 6 ژنوتیپ گندم (گونه های گندم تریتیکاله و دوروم (رقم بلیخ – 2) و ارقام الوند، فلات، c755 و طوس) و دو مقدار مصرف آهن (صفر و 10 کیلوگرم در هکتار کلات fe-eddha) بود. نتایج نشان داد مصرف آهن به طور میانگین، موجب افزایش معنی‌دار عملکرد دانه (p< 0.05) به میزان 9/9 درصد نسبت به شاهد گردید. در بین ژنوتیپ های گندم، بیشترین افزایش عملکرد در گندم دوروم به میزان 1/17 درصد) و کمترین آن در گندم رقم طوس (به میزان 1/4 درصد) بدست آمد. در اثر مصرف آهن، تغییر غلظت آهن در دانه، علی رغم 7/5 درصد افزایش، از نظر آماری معنی‌دار نگردید. ولی جذب آهن در دانه گندم به میزان 4/16 درصد افزایش معنی‌داری یافت (p<0.01). کارایی مــصرف آهن در ژنوتیپ های مختــلف گندم به صورت: طوس و فــلات> تریتیـکاله> الــوند> c75-5> دوروم بدست آمد.

Application and Fertilization Efficiency of Iron in Some Wheat Genotypes

Introduction: World cereal demand is growing at present in accordance with the global expansion of human populations. Deficiency of micronutrients in cereal cropping is one of the major worldwide problems. Beside of lowering grain yield, it may cause some healthy problems in human populations. Iron is an essential micro element in the soil that mainly had been found as the insoluble (Ferric or Fe3+) form. Although ferric iron is relatively insoluble in water, the solubility of total inorganic iron decreases between pH of 7.4 to 8.5 range which is dominant in calcareous soils. It is estimated that nearly half of the world population is affected from Fe deficiency problem. Major reason for widespread occurrence of Fe deficiency in human populations is very little dietary diversity and high consumption of cerealbased foods with very low amount and poor availability of Fe. Bread wheat is the most widely grown cereal grain with 65% (6.5 million hectares) of the total crop cultivated area in calcareous soils of Iran. Most wheat cultivars currently used have been selected for high yields under optimum fertilizer conditions. Consequently, research is needed to select efficient genotypes that will grow and produce under conditions of lower fertilizer input or soil micronutrients deficiencies. This is especially true for the expansion of wheat cultivation which is often growing in calcareous soil of Iran. These soils are characterized with low fertility, high pH value, low organic matter content and low micronutrients availability. Environmental concerns in wheat production for human population indicate that to improve wheat quality and quantity, the zero or possible lowest amounts of chemical fertilizers would be applied. In this regard, the use of ironefficient genotypes that have also high yield can be considered as a key strategy. Materials and Methods: In order to investigate Fe efficiency in various wheat genotypes, a factorial experiments a randomized complete block design was carried out with three replications in agricultural and natural resource research and education center of Khorasan Razavi province, Mashhad (Torough Station), Iran, during 20092011. Treatments were consisted of two levels of Fe fertilizer (0 and 10 kg h1 as FeEDDHA) and six genotyps of wheat including: three cultivars and one line of bread wheat (Alvand, Falat, Toos, and C755, respectively), two species of wheat known as Thriticosecale and Durum. The trial plots’s size was 9×3.6 (32.4 m2). According to the results of soil analysis, total nitrogen, available forms of phosphorus and potassium were 0.05%, 7.2, and 180 mg kg1, respectively. DTPA extractable of iron, zinc, manganese and copper were 2.4, 0.52, 3.4 and 0.7 mg kg1, respectively. Soil texture was silt loam. Soil organic carbon percentage and equivalent CaCO3 percentage (T.N.V) were 0.48% and 18.7%, respectively. The electrical conductivity (EC) and pH measured in saturated extract were 1.4 dSm1 and 8.1, respectively. At defined phonological stage (SG6 based on Fix’s Index), the Fe concentration in shrub was measured. Moreover, grain yield and Fe uptake by grain were determined at the end of ripening stage. Iron use efficiency, agronomic efficiency and apparent recovery efficiency were calculated and studied as dependent variables.Results and Discussion: The grain yield is the most integrative trait of a particular genotype. The results showed that Fe application increased significantly grain yield by 9.9% in comparison with control. In our research the highest grain yield increase due to Fe application was found in Durum wheat (17.1%), and the lowest grain yield increase, were found in Toos cultivar (4.1% yield increase). Application of Fe increased Fe concentration and uptake in grain about 5.7% and 16.4%, respectively. In terms of iron uptake by grain, Thriticosecale wheat and C755 cultivar had the highest (339.6 g ha1) and the lowest amounts of Fe uptake (260.3 g ha1), respectively. Also, application of Fe had no significant effects on Fe concentration in shoot. Fe use efficiency in bread wheat genotype, Durum and Thriticosecale wheat was ranked as: Durum < C755 < Alvand < Triticale < Falat < Toos. According to our research results, Toos and Falat cultivars and Thriticosecale have higher iron use efficiency than Alvand and C755 cultivars and Durum wheat. The results also suggest that to obtain higher yield in Durum wheat, soil and foliar application of Feis more necessary in comparison with other genotypes especially Toos and Falat.Conclusion: There were various abilities to uptake and use Fe by different wheat genotypes. Feefficient genotypes of wheat were Toos and Falat also Triticale. Moreover, these genotypes also had higher grain yield.