payman keshavars; majid forouhar; masoud Dadivar
Abstract
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 ...
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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 cereal-based 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 iron-efficient 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 2009-2011. Treatments were consisted of two levels of Fe fertilizer (0 and 10 kg h-1 as Fe-EDDHA) and six genotyps of wheat including: three cultivars and one line of bread wheat (Alvand, Falat, Toos, and C75-5, 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 kg-1, respectively. DTPA extractable of iron, zinc, manganese and copper were 2.4, 0.52, 3.4 and 0.7 mg kg-1, 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 dSm-1 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 C75-5 cultivar had the highest (339.6 g ha-1) and the lowest amounts of Fe uptake (260.3 g ha-1), 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 < C75-5 < Alvand < Triticale< Falat < Toos. According to our research results, Toos and Falat cultivars and Thriticosecale have higher iron use efficiency than Alvand and C75-5 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. Fe-efficient genotypes of wheat were Toos and Falat also Triticale. Moreover, these genotypes also had higher grain yield.
P. Keshavarz; M. Forouhar; M. Dadivar
Abstract
Introduction: World cereal demand is growing at the present in accordance with the global expansion of human populations.Bread wheat is the most widely grown cereal grain with 65% (6.5 million hectares) of the total crop cultivated area in Iran. Deficiency of micronutrients in cereal cropping is one ...
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Introduction: World cereal demand is growing at the present in accordance with the global expansion of human populations.Bread wheat is the most widely grown cereal grain with 65% (6.5 million hectares) of the total crop cultivated area in Iran. Deficiency of micronutrients in cereal cropping is one of the major worldwide problems. Zinc (Zn) is an essential micronutrient for plants. It plays a key role as a structural constituent or regulatory co-factor of a wide range of different enzymes and proteins in many important biochemical pathways. Nearly half of the world’s cereal-growing areas are affected by soil zinc deficiency, particularly in calcareous soils of arid and semiarid regions. High pH levels and bicarbonate anion concentration in these soils are the major factors resulting in low availability of Zn. About 40% of the soils, used for wheat production in Iran are Zn-deficient, which results in a decrease in growth and wheat grain yield under field conditions. Although application of zinc fertilizers is a common practice to correct Zn deficiency, growing varieties with high Zn efficiency has been reported to be a more sustainable approach. There is significant genetic variation both within and between plant species in their ability to maintain significant growth and yield under Zn deficiency conditions. Plant response to Zn deficiency and Zn fertilization are two distinct concepts. Knowing about these variations, can be very essential and useful for making correct fertilizer recommendation.
Materials and Methods: In order to investigate Zn efficiency in various wheat genotypes, a factorial experiment as a randomized complete block design was carried out with three replications in agricultural research center of Khorasan razavi (Torough Station), during 2009-2011. Treatments consisted of two levels of Zn fertilizer (0 and 40 kg/h as ZnSO4) and six genotyps of wheat including: three cultivars and one line of bread wheat (Alvand, Falat, Toos, and C75-5 respectively), two species of wheat known as Thriticosecale and Durum. The plot size was 9*3.6 (32.4 m2). Soil fertility status showed 0.05% nitrogen, 7.2 mgkg-1 phosphorus, 180 mgkg-1 potassium and 0.52 mgkg-1 DTPA extractable zinc. At defined phonological stage (SG6 based on Fix’s Index) Zn concentration in shrub was measured. Also grain yield and Zn uptake by grain were determined at the end of ripening stage. Zinc use efficiency, agronomic efficiency and apparent recovery efficiency were calculated according to “Graham, et al.”, “Craswell and Godwin” and “Raun and Johnson” respectively. Zinc use efficiency can be defined as the ratio of grain yield or shoot dry matter yield produced under Zn deficiency to that produced under Zn fertilization.
Results and Discussion: Grain yield is the most integrative trait of a particular genotype. The results showed that Zn application increased significantly grain yield by 12.61% in comparison with control. This result is supported by Ziayeian and Malakouti (1999). Who reported that Zn application significantly increased the wheat yield (17%). In our research the highest grain yield increase due to Zn application was found in durum wheat (23.5%), and the lowest grain yield increase, were found in Toos cultivar (1.3% yield increase). Cakmak and et al (1997) also obtained more yield with the application of zinc in durum wheat. Application of Zn increased Zn concentration and uptake in grain, 8.6% and 21.5% respectively. Also, application of Zn significantly increased Zn concentration in shoot (36.5%) over the control. Similarly, Moshiri et al (2010) reported increase of Zn concentration in shoot with application of Zn fertilizer. Zn use efficiency in bread wheat genotype, Durum and Thriticosecale wheat was ranked as: Durum < C75-5 < Alvand < Falat < Triticale ~ Toos. The findings of Khoshgoftarmanesh et al (2004) showed that, Durum wheat is Zn inefficient genotype. According to our research results, Toos and Falat cultivars and Thriticosecale have higher efficiency than Alvand and C75-5 cultivars and Durum wheat. The results also suggest that to obtain higher yield in Durum wheat, soil and foliar application of Zn is more necessary in comparison with other genotypes especially Toos and Thriticosecale.
Conclusion: wheat genotypes were different in their response to Zn deficiency and Zn supply. Thriticosecale and Toos were the most Zn efficient genotypes, whereas Durum and C75-5 were the most responding to Zn supply. So, without considering these differences, accurate fertilizer recommendation cannot be achieved. For organic farming and low input agriculture systems in regions similar to this experiment location (Torough Station), Thriticosecale and Toos could be suggested. However, for improvement of wheat grain yield and achieve desired quality in calcareous soil, most of the time, it is necessary to use the Zinc fertilizers.
