Search

In this study, long-term effects of salinity and high boron (B) on subcellular distribution of sugars in wheat leaves were investigated. Four treatments with three replications of each; control, high B, sodium chloride (NaCl) and NaCl + high B, respectively were established according to completely randomized design. Plants were grown hydroponically and harvested after 6 weeks onset of experiment. NaCl treatment markedly decreased the shoot fresh and dry weight compared to high B or NaCl + high Boron. It increased the sugar concentrations in subcellular compartments, whereas decreased in NaCl + high B. Contrary, NaCl either alone or in combination with high B decreased the sugar contents in whole leaf compared to control or high B. Overall, higher concentrations of sugars were observed in symplast compared to apoplast indicating the symplast as major compartment for sugar transport. Furthermore, wheat plants accumulate sugars in subcellular compartments to maintain their growth under stress conditions. [ABSTRACT FROM AUTHOR]

The aim of this 2-year field experiment was to investigate agronomic and economic efficiency of ground tire rubber and rubber ash as zinc (Zn) sources for wheat (Triticum aestivumL. cvs. Kavir and Back Cross) compared with a commercial zinc sulfate (ZnSO4). A similar rate of Zn was used by soil incorporation of 40 kg/ha ZnSO4, 200 kg/ha waste tire rubber ash, and 1000 kg/ha ground rubber. A no Zn added treatment was also considered as control. All Zn fertilizers significantly increased grain yield of wheat over the control, although effectiveness of rubber ash was greater than the other Zn sources. Wheat plants treated with rubber ash accumulated higher Zn in their grains compared with those treated with ground rubber and ZnSO4. Tire rubber ash had the highest agronomic and economic efficiency and contained low levels of cadmium (Cd) and lead (Pb). Therefore, it can be used as an economic substitution for commercial ZnSO4. [ABSTRACT FROM AUTHOR]

In this study, impact of silicon (Si) application on wheat performance under drought stress is studied. Experimental soil was sandy clay loam with an average pH of 8.01, electrical conductivity (EC) of 2.36 dSm−1, and calcium carbonate (CaCO3) content of 2.16%. Soil was severely deficient in organic matter (<1%). Average extractable phosphorus (P) and potassium (K) concentration was 230 and 5.21 mg kg−1, respectively. Silicon potassium metasilicate (K2SiO3) was applied at the rate of 0 and 12 kg/ha with three canal water irrigation frequencies including two, three, and four under randomized complete block design (RCBD) factorial fashion with three replications. Results indicated that drought stress significantly reduced plant height, spike length, shoot fresh weight, and number of spikelets/spike, eventually enhancing wheat yield. Concentration of K+in shoot (28.65 mg g−1) and grains (3.51 mg g−1) increased with Si application, which helped to maintain water potential in plant even under reduced moisture level in plants and soil, ultimately producing more yield and biomass under drought stress conditions. [ABSTRACT FROM AUTHOR]

Hydroponic culture technique is an alternative way of studying nitrogen metabolism. In this study, the response of six wheat genotypes (PBW 621, PBW 636, GLU 1356, BW 8989, GLU 700, and PBW 343) with respect to nitrogen-metabolizing enzymes in relation to accumulation of soluble proteins and amino acids at two concentrations of nitrogen (2 and 6 mM) was studied. Activities of nitrate reductase (NR) and glutamine synthetase as well as soluble proteins, amino acids, and nitrogen content increased in all six genotypes with increasing concentration of nitrogen in roots as well as shoots. Shoots maintained higher activities of NR and glutamine synthetase; apparently contents of soluble protein, amino acid, and nitrogen were also higher. The upregulation of NR and glutamine synthetase activities with increased concentration of nitrogen possibly contributes to higher nitrogen assimilation efficiency of three genotypes (PBW 621, PBW 636, and GLU 1356) compared to other genotypes. [ABSTRACT FROM AUTHOR]

Nutritive value of winter cereal forages is one of interested subjects of farmers for animal feeding. Field experiments were established in 2007–2008 and 2008–2009 growing seasons in northeast Turkey to investigate the effect of organic solid cattle manure application (0, 10 and 20 Mg ha−1yr−1) on nutritive value of three annual cereals for forage. The winter cereal forages were: wheat (Triticum aestivumL.), oat (Avena sativaL.) and rye (Secela cerealeL.). ADF (acid detergent fiber), NDF (neutral detergent fiber) CP (crude protein), nitrogen, phosphorus, potassium, sulfur, calcium, copper, iron, magnesium, manganese, sodium, zinc and boron (N, P, K, S, Ca, Cu, Fe, Mg, Mn, Na, Zn and B) concentrations were researched in this study. Wheat had the highest CP, N, Ca, Cu, Na and Zn concentration, whereas oat had the lowest ADF and NDF and the highest K, Fe and Mn concentrations. The greatest Mg and P concentrations were determined in rye. Organic solid cattle manure applications had no effect on N and CP contents, but it decreased ADF and NDF contents. However, in most cases it positively affected the P, B, Cu, Fe, Mg and Na concentrations, whereas it decreased K, Ca, Mn and Zn concentrations. The results showed that wheat and oat are more nutritive species than rye in terms of animal feeding and the organic solid cattle manure, in some cases increased the nutritive values of wheat, oat and rye under organic agriculture conditions. [ABSTRACT FROM AUTHOR]

This study aims to explain the effects of silicon (Si) foliar application on gas exchange characteristics, photosynthetic pigments, membrane stability and leaf relative water content of different wheat cultivars in the field under drought stress conditions. The experiment was arranged as a split-split plot based on randomized complete block design with three replications. Irrigation regime (100%, 60%, and 40% F.C.), silicon (control and Si application) and wheat cultivars (Shiraz, Marvdasht, Chamran, and Sirvan) were considered as main, sub and sub-sub plots, respectively. This study was carried out at the Research Farm of the Collage of Agriculture, Shiraz University, Iran, during 2012–2013 growing season. The results showed that foliar application of silicon increased the leaf relative water content, photosynthesis pigments (chlorophyll a, b and total chl and carotenoids), chlorophyll stability index (CSI) and membrane stability index (MSI) in all wheat cultivars, especially in Sirvan and Chamran (drought tolerant cultivars), under both stress and non-stress conditions. However, more improvement was observed under drought stress as compared to the non-stress condition. In contrast, these parameters decreased under drought stress. Si significantly decreased electrolyte leakage in all four cultivars under drought stress conditions. Furthermore, the intercellular carbon dioxide (CO2) concentration (Ci) increased under drought stress. Si application decreased Ciespecially under drought stress conditions. Net photosynthesis rate (A), transpiration rate (E) and stomatal conductance (gs) were significantly decreased under drought conditions. Under drought, Si applied plants showed significantly higher leaf photosynthesis rate, transpiration rate, and stomatal conductance. Intrinsic water use efficiency (WUEi) and carboxylation efficiency (CE) decreased in all cultivars under drought stress. However, the silicon-applied plants had greater WUEi and CEunder drought stress. The stomatal limitation was found to be higher in stressed plants compared to the control. Exogenously applied silicon also decreased stomatal limitation. Overall, application of Si was found beneficial for improving drought tolerance of wheat plants. [ABSTRACT FROM AUTHOR]

Nitrogen (N) is a major factor limiting grain production in the high rainfall zone (HRZ, 450–700 mm annual average rainfall of southwestern Australia (SWA). Transient waterlogging and leaching of applied N fertilizer are hazards faced in most years by crop producers. The major crops are wheat (Triticum aestivumL.), barley (Hordeum vulgareL.), canola (Brassica napusL.) and lupin (Lupinus angustifioliusL.) grown in rotation. Two series of experiments involving, levels and timing of N fertilizer application and levels of plant population were done. The first series, in 2003–2004, consisted of 3 experiments in 3 growing seasons (early May to late-October) to measure the grain yield (GY) increase (response) of wheat and barley to various methods of N fertilizer application (methods of split N application were compared to N applied at sowing). The aim of the experiments was to determine the optimal N fertilizer application strategy for maximum GY and quality in situations where transient waterlogging was a frequent occurrence. The second series of four experiments, from 2007–2009, measured the GY of wheat sown at three levels of plant population to 4 levels of N applied after transient waterlogging (taken to be rainfall events in which >25 mm of rain was recorded in 24 to 48 hours). Applying the N fertilizer after high rainfall and transient waterlogging (tactical N application) increased GY and protein percentage of grain compared to applying all of the N fertilizer at sowing. Where transient waterlogging was not frequent, applying the N after waterlogging was not always better than applying part of the N according to growth stage of the crop or according to fixed times after sowing. When the crop was water-logged three or more times, N uptake by the crop at anthesis and apparent fertilizer N recovery in the crop was substantially increased by applying the N after waterlogging compared to applying the entire N at sowing. This study found that a tactical N management strategy for the HRZ of SWA is to apply some N at sowing with subsequent applications made after heavy rainfall that leads to transient waterlogging. Split N fertilizer applied either according to time after sowing or to growth stage of the crop was equally effective for increasing GY in situations where waterlogging was less frequent. The observation from these experiments, that grain yield increases due to splitting the N dose were associated with increases in ear numbers, lead to a further set of experiments where plant population was increased in conjunction with N applied after waterlogging events. The combined strategy of increased plant population with strategic N application decreased the amount of N required for maximum GY where more than 3 heavy rainfall events occurred in a growing season. One practical outcome of this research is to indicate that farmers can withhold applications of N fertilizer after sowing in seasons when transient waterlogging does not occur. [ABSTRACT FROM AUTHOR]

Phosphorus (P) mobilizing bacteria play an important role in the availability of soil and fertilizer P for all crops including wheat. Two greenhouse experiments were conducted to evaluate the effects of six P mobilizing bacterial strains and three P sources tricalcium phosphate {[Ca3(PO4)2], calcium hydrogen phosphate [CaHPO4.2H2O] and rock phosphate} on yield and P uptake of wheat. All the bacterial inoculants increased grain yield significantly over control in one greenhouse experiment while only three strains produced significantly higher grain yield over control in a second experiment. Difference among P sources were not significant in acquiring grain yield in experiment 1 while Ca3(PO4)2and CaHPO4.2H2O produced significantly higher grain yield over rock phosphate in experiment 2. The differential pattern in results in two experiments might be due to difference in growth conditions. More greenhouse studies as well field experiments are recommended to confirm the beneficial effects of these P mobilizing bacterial strains on wheat. [ABSTRACT FROM PUBLISHER]

Recovery and recycling of plant nutrients from municipal sewage effluent (SE) can reduce consumption of costly chemical fertilizers, besides reducing eutrophication of water bodies. Field experiment was conducted on Vertisol of central India for six years with the objective of quantifying recovery of major plant nutrients by aboveground biomass of wheat-soybean cropping system from untreated SE. Wheat crop was grown with irrigation (groundwater and sewage effluent) and fertilizer treatments; while soybean was grown without any treatments. Recoveries of nitrogen (N), phosphorus P) and potassium (K) by the aboveground biomass were considerably more from SE than from fertilizers and manures. Recovery of nutrients from SE was the highest by wheat grain for N and by soybean straw for P and K. Straw biomass of both the crops recovered about 31% N, 22% P and 69% K from SE, which can be recycled back into agricultural land of groundwater (GW) irrigated as well as rainfed area. [ABSTRACT FROM PUBLISHER]

A two year field experiment was conducted in field conditions using wheat (Triticum aestivumssp. vulgare L. cv. Bezostaja) as the test plant for the evaluation of phosphate solubilizing (+PS) microorganisms. Bacterial strains significantly (P < 0.05) increased plant biomass (by 13 to 36%) without plant P enrichment. OnlyBacillussp. #189 significantly (P < 0.05) raised plant P-content, biomass and rhizosphere soil Olsen P at Zadoks Scale 62 simultaneously. Inoculations variably increased plant potassium (K-), magnesium (Mg-), zinc (Zn-), and managenese (Mn-) contents at harvest (Zadoks 92) but not earlier (Zadoks 31 and 61). The enrichment of the inoculated plants with nutrients other than P indicates the presence of alternative plant growth promoting mechanisms. This study showed that promising phosphate solubilizing microorganisms could increase not only the P content of the plants, but also the soil available P in rhizosphere transiently. [ABSTRACT FROM PUBLISHER]

Investigations were focused on light effects on allocation of root-borne macronutrients (calcium, magnesium and potassium) and micronutrients (iron, manganese, zinc and copper) in roots, shoots and harvested grains of wheat (Triticum aestivumL.). Plants were exposed to low (100 μmol photons m−2s−1) or high light (380 μmol photons m−2s−1). High light stimulated both root and shoot growth. While the total contents per plant of some nutrients were markedly higher (calcium and potassium) or lower (copper) under high light, no major differences were observed for other nutrients. The distribution of nutrients and the further redistribution within the shoot were influenced by the light intensity in an element-specific manner. Nutrients were selectively directed to the leaves of the main shoot (low light) or to the tillers (high light). The quality of the harvested grains was also affected by the light intensity. [ABSTRACT FROM AUTHOR]

The objectives were to determine the effect of different levels of foliar iron fertilization on the some physical properties and breakage susceptibility of wheat seed. Foliar iron treatments were combinations of three fertilization rates [0 (control), 1.2 and 2 L ha−1, Fusin] at three replications. The harvested seeds were then subjected to impact energies of 0.1 and 0.2 J, at moisture contents of 8.5, 15, 20 and 25% (w.b.), using an impact test apparatus. Results indicated that the values of the seed physical properties increased with increasing iron rate. Iron fertilizer rate, moisture content and the interaction between two variables significantly influenced breakage susceptibility of wheat seeds at the 1% probability level (P < 0.01). Resistance to the breakage of wheat seeds increased following a polynomial relationship with increase in the foliar iron rate. Increasing the rate of foliar iron from 0 to 2 L ha−1 caused a significant decrease in the mean values of damage by a factor of 1.8 from 66.188 to 36.688%. As the moisture content of the seeds increased from 8.5 to 25%, the amount of the percentage breakage of seeds decreased, as a polynomial. The maximum rate of decrease in the damage to seeds, with increasing moisture content, was obtained at higher iron fertilizer rates. [ABSTRACT FROM AUTHOR]

The effects of soil residual nitrate (NO3-N) and ammonium (NH4-4) on wheat (Triticum aestivum L.) grain yield and N uptake were evaluated in a three-year experiment from 1991 to 1993, in the province of Quebec, Canada. Soil samples were collected at harvest from the depth of 0-30 and 30–60 cm from 20 wheat sites and analyzed in the laboratory for NO3-N and NH4-N. Wheat yield and N-uptake was also determined. Using statistical analysis system (SAS) and Matlab, data were analyzed and the best-fitted regression equations were plotted. Significant amounts of soil NO3-N was found in the soil ranging from 31.6 to 61.6 kg/ha. The amount of soil NH4-N varied from 9.2 to 23.3 kg/ha. The statistical effects of model parameters indicated that soil NO3-N and soil NH4-N significantly influenced wheat yield and N uptake. It may be possible to investigate wheat behavior at harvest using soil residual NO3-N and NH4-N. [ABSTRACT FROM AUTHOR]

Eighteen bread wheat (Triticum aestivum L.) and two durum wheat genotypes (Triticum turgidum L.) were used to explore relationship among their morpho-physiological traits. Two separate field experiments were conducted at the Experimental Station, College of Agricultural, Shiraz University. Each experiment was designed as a randomized completed block with three replications. Twenty-five morpho-physiological drought resistance related traits were measured and multivariate statistical techniques were used to consider these relationships. Based on the results of the factor analysis, electrolyte leakage (EL) had the highest positive correlation, while membrane stability index (MSI) had the highest negative correlation with the first factor, canopy temperature depression (CTD). It could be clearly detected that these two variables had high effect on canopy temperature and the genotype with lower EL and higher MSI resulted in lower canopy temperature. This factor also showed that reactive oxygen species (ROS) related traits and plant water relationship related traits had significant effect on CTD. Since yield stability (YS) had the highest coefficient in factor 3, this factor was the most important one showing effective variables on this trait, thus this factor's suggested name was YS. The significant positive correlations with factor 3 were relative water protected (RWP), which is a new index, and cellular membrane stability (CMS). This result clearly shows that new index of RWP can be an efficient indirect criterion to screen higher YS genotypes together with CMS. Cluster analysis grouped variables into three clusters. These results were confirmed by the results of principal and discriminate function analysis. In addition, the results of the factor analysis for considering relationships among measured traits were confirmed through the cluster analysis. [ABSTRACT FROM AUTHOR]

A pot experiment was conducted in the wire house of Department of Crop Physiology, University of Agriculture, Faisalabad to evaluate the effect of salinity stress on water relations, nutrient uptake and yield of six local spring wheat cultivars. The seeds were sown in plastic pots (25 × 15 cm) and experiment was laid out in a randomized complete block design in factorial arrangement with three repeats. De-ionized water was used as control treatment while salinity stress was imposed by irrigating plants with sodium chloride (NaCl) solution of 10 mM at tillering, stem elongation, anthesis, and grain development stages. Results of the study demonstrated that salinity stress decreased water potential by 32%, osmotic potential by 12%, and relative water contents by 20% as compared to control treatment. The nitrogen (N) uptake was decreased by 36% under salinity stress, while phosphorous (P) and potassium (K) uptake were decreased by 56% and 42%, respectively. The yield of wheat plants was also significantly reduced under salinity stress. It reduced grain yield by 25% and grain weight by 7%. The response of different cultivars was also different to salinity stress as cultivars ‘Lasani-08’ and ‘FSD-08’ were found to be more tolerant as compared to other cultivars. [ABSTRACT FROM PUBLISHER]

A pot experiment was conducted to evaluate the foliar applied phosphorous with and without pre-plant dose (50 kg hac.−1) of phosphorous on growth, chlorophyll contents, gas exchange parameters and phosphorous use efficiency (PUE) of wheat. The experiment was conducted in net house at Department of Crop Physiology, University of Agriculture Faisalabad, Pakistan. Two promising wheat cultivar AARI 2011 and FSD 2008 were used as a test crop with 5 foliar phosphorus (P) rates (0, 2, 4, 6, 8 kg ha−1). The foliar applied P with pre-plant performed better than without pre-plant and control treatments. Foliar treatment of phosphorus at 6 kg ha−1P proved to be the best among other foliar treatments followed by 8 kg ha−1P. The foliar application of phosphorous at 6 kg hac.−1with pre-plant soil applied P increased the shoot length, root length, shoot fresh weight, root fresh weight, shoot dry weight and root dry weight. The chlorophyll contents (Chl. a and b) were increased with the foliar application of phosphorous. The gas exchange parameters (net carbon dioxide (CO2) assimilation rate, transpiration rate, stomatal conductance and sub-stomatal CO2rate) were significantly improved by foliar applied P. The maximum values of net CO2assimilation rate (5.27 μ mol m−2sec.−1), transpiration rate (3.44 μ mol m−2sec.−1), stomatal conductance (0.81 μ mol m−2sec.−1) and sub-stomatal CO2(271.67 μ mol m−2sec.−1), were recorded in the treatment where P was foliar applied at 6 kg hac.−1with pre-plant soil applied Phosphorous. The foliar application of phosphorous with pre-plant soil applied P enhanced Phosphorous use efficiency (PUE) in both varieties. The maximum value of PUE (15.42%) was recorded in the treatment where foliar feeding of P was done at 6 kg hac.−1with pre-plant soil applied P in both genotypes. [ABSTRACT FROM AUTHOR]

Leaf thickness plays an important role in leaf and plant functioning and is related to species’ strategies of resource acquisition and use. Leaf thickness in small grains crops was measured as specific leaf area (SLA) (leaf area in cm2produced g−1leaf dry weight plant−1) and specific leaf weight (SLW) (leaf dry weight in mg produced cm−2leaf area plant−1). The four small grains crops (cool season C3cereals) studied were wheat (Triticum aestivumL.), rye (Secale cerealeL.), barley (Hordeum vulgareL.) and oats (Avena sativaL.). The null hypothesis tested was that SLA and SLW in small grain crops do not differ at different growth stages and nitrogen, phosphorus, and potassium (NPK) source. Eight NPK sources used in the experiment were: S1= 20-20-20, S2= 20-27-5, S3= 7-22-8, S4= 10-10-10-20S, S5= 11-15-11, S6= 31-11-11, S7= 24-8-16, and S8= 19-6-12, and each was applied at the rate of 300 mg pot−1at the time of sowing to each crop species. The experiment was performed in completely randomized design with three repeats at the Green House of Dryland Agriculture Institute, West Texas A&M University, Texas, during winter 2009-10. Based on the results, it was observed that both SLA and SLW differed with change in crop species, growth stage and NPK source. Among the crop species, SLA was greater in oats > barley > rye > wheat at different growth stages; while SLW of wheat and rye > barley and oats. The differences in the SLW between wheat vs. rye; and between oats vs. barley at different growth stages were not significant (P ≤ 0.05). Among the NPK sources, application of S7(24: 8: 16) had higher SLA at 60 and 90 DAE (days after emergence). Application of S6(31: 11: 11) had higher SLW at 60 DAE due to the production of the lowest leaf area plant−1, but the increase in SLW at 90 DAE with S5and S4was due to the higher leaf dry weight plant−1produced. Leaf dry weight and leaf area plant−1were considered the two most important leaf characteristics that influenced SLA and SLW. On the average, SLA increased with passage of time i.e. 0.70 < 520 < 600 cm2g−1at 30, 60 and 90 DAE, respectively; but SLW on the other hand, was highest 3.5 at 60 DAE > 2.2 at 90 DAE > 1.5 mg cm−2at 30 DAE. The increase in leaf area plant−1and decline in the leaf dry weight plant−1increased SLA; in contrast, increase in leaf dry weight plant−1and reduction in leaf area plant−1increased SLW indicated reciprocal relationship between SLA and SLW in the crop species. [ABSTRACT FROM AUTHOR]

Wheat genotypes display differential tolerance to manganese (Mn) deficiency. Growing Mn-efficient cultivars in Mn deficient soil could be effective in improving yields. A pot experiment was conducted with eight genotypes grown in Mn deficient soil treated with 0 (no Mn fertilizer) and 50 ppm (50 mg Mn kg−1soil applied as mangansese sulfate monohydrate (MnSO4.H2O) Mn. The genotypes were classified on the basis of grain yield and grain physiological efficiency as efficient and responsive (SAMNYT 410, GLUPRO 200, PBW 621, and BW 9178), efficient and nonresponsive, inefficient and responsive (HD 2967), and inefficient and nonresponsive (PDW 314, PDW 291, and PBW 636). The genotypes in different groups differed in morphophysiological characteristics; efficient and responsive genotypes recorded more leaf area, higher SPAD index, higher Fv/Fm ratio, and longer roots than inefficient and nonresponsive. Efficient and responsive genotypes are desirable by farmers, whereas inefficient and responsive genotypes in a breeding program for their Mn-responsive characteristics. [ABSTRACT FROM AUTHOR]

Management practices have significant effects on crop micronutrient contents. This study examined effects of applying chemical fertilizers of nitrogen (N), phosphorus (P), and potassium (K) (NPK), alone or supplemented with straw or manure, under a wheat-maize cropping system in a 18-year experiment, on the crops’ iron (Fe), manganese (Mn), copper (Cu), and zinc (Zn) contents throughout the crops’ development. The micronutrient contents of both wheat and maize were above critical values during vegetative development, but Zn contents of maize ear leaves were sub-sufficient under all treatments. The wheat grain Mn, Cu, and Zn contents were lower under fertilized treatments than in unfertilized controls. Nutrient balance calculations showed that NPK application alone or with straw resulted in deficits of the four micronutrients, but not application of NPK supplemented with manure. Hence, application of micronutrients, such as Zn, through organic or inorganic fertilizers is recommended for this cropping system. [ABSTRACT FROM PUBLISHER]

To find effective alternatives to reduce the application of conventional urea (CU), a conventional biofertilizer (CB) preparation (charcoal mixedAzotobacter chroococcumandBacillus subtilis) and the same biofertilizers entrapped in an organic matrix consisting of cow dung, rice bran, dried powder of neem leaves, and clay soil in 1:1:1:1 ratio and 25% (w/w) saresh (plant gum ofAcaciasp.), named as super granules of biofertilizers (SGBF) were applied to cultivate wheat (Triticum aestivumL. cv. ‘WH-711’) in experimental plots. The results revealed that the efficacy of commercially available charcoal mixed biofertilizers could not prove as effective alternative to CU, whereas the same dose of biofertilizers entrapped in the organic matrix, SGBF, resulted in a significant increase in growth and productivity of wheat. It appears that SGBF prepared and applied in this study is an effective organic alternative to the urea for wheat cultivation in semi-arid subtropical agro-ecosystems. [ABSTRACT FROM AUTHOR]

The effect of inoculation ofRhizobiumorPseudomonas,or both, in the presence and absence of phosphorus pentoxide (P2O5) fertilizer on wheat yield was tested. The experiment was conducted outdoors in potted soil during two consecutive years under natural conditions. Rhizobial strain (Thal 8-chickpea nodulating bacteria) andPseudomonasstrain (54RB), both indigenous P solubilizers were applied in broth culture at seedling stage. Fertilizer in the form of P2O5was an additional treatment applied at sowing time. Results revealed that inoculation ofPseudomonasstrain in presence of phosphorus (P) fertilizer increased yield up to 41.8% when it was compared with only P fertilizer applied. Co-inoculation ofRhizobiumandPseudomonasstrains with the P2O5treatment however resulted in increased grains yield by 10% over the P2O5treatment alone. It is inferred that inoculation withRhizobiumandPseudomonascombined with P2O5is not only environmentally beneficial but also economically sound and productive, with wheat yield increases of 10% to 42%. [ABSTRACT FROM AUTHOR]

A study was conducted under greenhouse conditions on wheat to investigate the utilization of dissolved organic nitrogen (N) in comparison with conventionally applied inorganic N sources (INS). Nitrogen was applied at a rate of 90 kg N ha−1in an inorganic form, an organic high molecular weight (MW) form (casein, haemoglobin, albumin), and an organic low MW amino acid form (glycine, alanine, valine). Inorganic N sources recorded the maximum response (126% to 150%) in total dry matter (DM) production while dissolved organic nitrogen (DON) sources showed 61% to 116% increase in comparison to the control treatment. Glycine gave the maximum DM production, which was comparable with both INS treatments. In hydroponics, greater utilization occurred and the shoots had a higher N content in comparison to those grown in soil. The concentration of DON and NO3−in soil after wheat harvest was similar in all the treatments. [ABSTRACT FROM AUTHOR]

Inoculation of wheat and corn grains with formulations of Azospirillum brasilense significantly increased seedling growth parameters of wheat and corn compared to untreated controls. Inoculation with Azospirillum and supplemental Trichoderma harzianum free or coimmobilized in calcium alginate resulted in significant increase in all plant growth parameters in addition to improving plant nutrient-content [phosphorus (P), potassium (K), and calcium (Ca)]. Grain treatments with T. harzianum alone or in a combination with A. brasilense were protected from invasion by Fusarium in a pot experiment. Nitrogen (N) fixation was investigated by A. brasilense free or double inoculated with T. harzianum in soil amended with different C-sources; also, phosphate solubilization was tested by these two organisms. Single and double inoculation with A. brasilense and/or T. harzianum improved wheat yield growth parameters in addition to seed protein; therefore, immobilized and coimmobilized formulations could be used as biofertilizer and biopesticide, and might be recommended to avoid the extensive use of the agrochemicals. [ABSTRACT FROM AUTHOR]

Shoot-root ratio (S:R), dry matter partitioning (DMP), and water use efficiency (WUE) response of wheat (Triticum aestivumL.) vs. rye (Secale cerealeL.) was investigated under organic [organic compost (OC), Miracle Grow (MG), sunshine peat moss (SPM), and Garden Basic peat humus (GBPM)], and inorganic soils [canyon soil (CS) and amarillo soil (AS)] in pot experiment at Dryland Agriculture Institute, West Texas A&M University, College Station, Texas, USA, during winter 2009–2010. The experiment was performed in completely randomized design (CRD) with three repeats. The objective of this experiment was whether S:R, DMP, and WUE of wheat versus rye differ under organic and inorganic soils. The results revealed that both crops responded differently in terms of S:R, DMP, and WUE under different organic and inorganic soils. Wheat had higher WUE than rye at different growth stages. Among the soil types, the three organic soils (MG, SPM, and GBPS) had higher WUE than the two inorganic (CS and AS) soils. The higher WUE of both crops when grown in organic soils such as MG, SPM, and GBPS was due to the higher dry matter partitioning to shoots and roots. The total dry weight plant−1showed positive relationship with WUE. [ABSTRACT FROM AUTHOR]

Long term effects of lantana (Lantana cameraL.) residue and fertilizer application were studied on copper (Cu) fractions in a Typic Hapludalf under rice-wheat cropping at Palampur, India (32°6′N, 76°3′E). A partitioning of soil Cu revealed residual Cu and organically bound Cu as the most dominant fractions followed by Cu occluded by free oxides, specifically exchangeable Cu and soil solution and exchangeable Cu. Continuous incorporation of lantana after 12 years resulted in redistribution of Cu from non-available forms to readily and potentially available forms in soil. All the Cu fractions were positively interrelated amongst themselves and with grain yield and Cu uptake in rice and wheat crops. Specifically exchangeable Cu followed by organically bound Cu were the most important Cu fraction contributing towards grain yield and Cu uptake in rice and wheat crops. [ABSTRACT FROM PUBLISHER]

Efficient use of nitrogen (N) by wheat crop and hence prevention of possible contamination of ground and surface waters by nitrates has aroused environmental concerns. The present study was conducted in drainage lysimeters for three years (1998–2000) to identify whether spring wheat genotypes (Triticum aestivumL.) that differ in N-related traits differ in N leaching and to relate parameters of N use efficiency (NUE) with parameters of N leaching. For this reason two spring wheat cultivars (‘Albis’ and ‘Toronit’) and an experimental line (‘L94491’) were grown under low (20 kg N ha−1) and ample N supply (270 kg N ha−1). The genotypes varied in parameters of NUE but not in N leaching. Grain yield of the high-protein line (‘L94491’) was, on average, 11% lower than that of ‘Toronit’ but among genotypes had significantly higher N in the grain (%), grain N yield, and N harvest index. Nitrogen lost through leaching was considerably low (0.42–0.52 g m−2) mainly due to low volume of percolating water or the ability of the genotypes to efficiently exploit soil mineral N. There were no clear relationships between N-related genotype traits and N leaching, but across all treatments significantly negative correlations between volume of leachate and the amount of N in the total biomass and grain N yield existed. [ABSTRACT FROM PUBLISHER]

In recent years, considerable interest has been focused on the use of physiological parameters as selection criteria in salt tolerance ranking. Eighteen bread wheat (Triticum aestivumL.) landraces from the west area of the Urmia Saline Lake were grown in a greenhouse in the Department of Plant Biology and Halophytes Biotechnology Center, Azarbaijan University of Tarbiyat Moallem, Tabriz, Iran to study the effects of increasing levels of sodium chloride (NaCl) (control, 75, and 150 mM) on the plant leaves. The experimental design was factorial with a randomized complete block with three replications. The results showed salinity caused an obvious decrease in growth of all landraces. Physiological parameters such as lipid peroxidation, hydrogen peroxide (H2O2) content, and cell membrane injury increased with increasing salinity levels with different degrees among the landraces. Salt stress increased the sodium (Na+) accumulation coupled with a decrease in leaf potassium (K+) depending on salinity levels. The analysis of variance showed significant effects of salinity, landraces and their interactions in all studied parameters. The landraces were ranked for salt tolerance indexes, and cluster group ranking ordered landraces from tolerant to sensitive and their properties for salt stress tolerance are open for further research. [ABSTRACT FROM PUBLISHER]

Field experiments were conducted over 2 years with the hypothesis that farmyard manure (FYM), soybean residue (SR) as sole and/or in combination with urea under different tillage practices has similar effects on crop nitrogen (N) status and accumulation of dry matter (DM). Conventional ploughed plots had higher DM than other. Post anthesis accumulation of DM for minimum tillage (MT) was 4% higher than DT. Incorporation of 20 tons FYM ha−1combined with 30 or 60 kg ha−1had higher DM and N partitioned to leaves, stem, and spike than control. Leaves accumulated more DM at anthesis stage than other, whereas stem and spike at maturity than earlier stages. Fertilized plots had higher DM and N redistribution efficiency than control. However, N remobilization increased linearly with increasing DM accumulation (r2= 22%). It was concluded that FYM coupled with N under MT showed marked variations for DM partition and N status in wheat than other treatments. [ABSTRACT FROM AUTHOR]

A field experiment was conducted at farmer's field in Mollisols ofTaraisoils in Uttarakhand (India), to assess the direct and residual effect of sulfur fertilization in wheat-soybean cropping sequence. Four levels of sulfur (S; 0, 15, 30, and 45 kg ha−1) were applied to main crop (wheat) along with recommended dose of nitrogen (N), phosphorous (P), and potassium (K). The direct and residual effect of sulfur at highest level showed 27 and 6 percent increase in grain yield of wheat and soybean over control, respectively. The increase in grain yield of wheat was significant at each sulfur level. The direct as well as residual effect of sulfur showed significant increase in sulfur concentration and its uptake by grain and straw except increase in sulfur concentration and uptake by soybean straw. In wheat-soybean cropping sequence, the agronomic efficiency and apparent sulfur recovery decreased with increase in levels of sulfur, but the percent response increased with increasing sulfur application. Different forms of sulfur such as total sulfur, organic sulfur, calcium chloride extractable sulfur, potassium dihydrogen phosphate extractable sulfur, and non-sulfate sulfur in post-harvest soil increased according to sulfur level applied but it decreased under control and also after residual crops. The buildup of sulfur in surface soils was greater than in the deeper soils. Application of sulfur showed the positive sulfur balance and it increased with increase in sulfur level, while it was negative under control. A major portion (46–62%) of applied sulfur contributed to increase in sulfur content of root zone soil followed by unaccounted component (25–40%) and small portion (11–18%) was absorbed by wheat plant as uptake. [ABSTRACT FROM AUTHOR]

Dairy manure (DM) rates of [0 (DM0), 30 (DM30)), 60 (DM60) Mg ha−1] and three nitrogen (N) rates [0 (N0), 125 (N125), 250 (N250) kg ha−1] were tested in a sandy clay loam, to evaluate their effects on growth and yield of wheat crop (Triticum aestivumL.), residual nitrate nitrogen (NO3-N) and phosphorus (P) concentrations in the surface soil, and selected soil physical measurements [saturated hydraulic conductivity (Ksat), and bulk density (BD)]. Increasing N and DM rates gave higher wheat yields, increased concentrations of residual NO3-N and P in the surface soil and improved Ksat and BD. Highest grain yield of 3.8 Mg ha−1(70.3% more than the control) was observed in DM60× N250treatment. Residual accumulation of N-NO3and P in the surface soil at high N and/or DM application rates suggests the need to carefully manage N and DM inputs on farm fields to avoid environmental contamination. [ABSTRACT FROM AUTHOR]

An experiment with factorial arrangement of treatments on a randomized complete block (RCB) design basis with three replications was conducted in a greenhouse during Spring 2010 to investigate changes in sodium ion (Na+), potassium ion (K+), Na+/K+and to determine proline, protein content, and superoxide dismutase (SOD) of four wheat and four barley cultivars. Three salt levels {1, control (no salt), 7, and 13 dS m−1[2.5 and 5 g salt [sodium chloride (NaCl) and sodium sulfate (Na2SO4) in 1:1 ratio] per kg of soil, respectively]} were used in this investigation. Salt stress treatments were applied 4 weeks after planting (at 2 leaf stage). Leaf samples were taken four weeks after imposition of salt treatment. The results showed that salinity caused an increased in proline and protein content, and SOD in all wheat and barley cultivars. The highest proline and protein content of barley and wheat cultivars at all salinity levels were observed in ‘Nimrooz’ and ‘Bam’ cultivars, respectively. At all salinity levels, wheat and barley cultivars ‘Kavir’ and ‘Nimrooz’, respectively, had the lowest Na+content. Barley cultivar ‘Kavir’ and wheat cultivar ‘Bam’ had higher K+and K+:Na+ratios. This might be related to salt tolerance in these two cultivars. Wheat and barley cultivars showed differences with regard to proline, protein, and SOD content, Na+, K+, and K+:Na+ratio, indicating existence of genetic diversity among the cultivars. These findings indicated that higher K+, K+:Na+ratio, proline, protein, and SOD content could be the key factors, which offer advantage to barley over wheat for superior performance under saline conditions. [ABSTRACT FROM AUTHOR]

A pot experiment was conducted to evaluate different arbuscular mycorrhiza sps. (AM) for their effect on plant growth, yield and nutrient uptake by wheat. All the AM fungal sps. significantly enhanced all the plant parameters and nutrient uptake by the plant. A positive correlation was observed between percent root colonization by AM fungi and most of the plant parameters studied.Glomus macrocarpumgiving best results was selected for studying interactive effect withAzotobacter,Azospirillum(well-known PGPRs), andFlavobacteriumandProteus vulgaris(less studied PGPRs). All the PGPRs significantly increased most of the plant parameters studied and their combination with AMF had a synergistic effect. Amongst PGPRs,Flavobacteriumgave best response both singly and in combination with AMF and thus, is a potential new bioinoculant for wheat. Application of 120 kg nitrogen (N) ha−1was the best treatment. Inoculation with most of the PGPRs gave better response than 60 kg N ha−1. [ABSTRACT FROM PUBLISHER]

Yield responses of wheat(Triticum aestivum L.)to elemental sulfur (S), mycorrhizae (mycorrhizal fungus,Glomus mosseae), and phosphorus (P) alone and collectively in two different soils were investigated. Plants were grown on calcareous sterilized Karaburun and Menekşe soils (sub-group of Typic Xerorthent). In the all treatments mycorrhizae inoculation alone compared to the control treatment increased shoot and root yields. The yield responses to S alone, P alone, and combined application of S and P in mycorrhizal and non-mycorrhizal treatments in two different soils were interestingly fluctuating. The findings obtained in this study indicated that S tended to increase the efficiency of mycorrhizae in the well aerated Karaburun soil in comparison to a less aerated (heavier textured) Menekşe soil. This potential to increase the efficiency of mycorrhizae on the root growth indicate that yield increase of shoot and grain can occur being an important finding for ecological agriculture. [ABSTRACT FROM PUBLISHER]

Seedrow-placed urea minimizes soil disturbance in reduced tillage systems, but it generally decreases seedling emergence (or stand density) at nitrogen (N) rates adequate for optimum crop yield. Two three-year field experiments were conducted on canola (Brassica napusL.) and spring wheat (Triticum turgidumL.) at Melfort Research Farm, Saskatchewan, Canada, to determine the influence of N rate (40, 80 and 120 kg N ha−1), N source [untreated urea (urea), polymer-coated urea (ESN), and urea treated with Dicyandiamide (DCD) and N-(n-butyl) thiophosphoric triamide (NBPT or AgrotainTM) (SuperU) in 2007, or NBPT only (AgrotainU) in 2008 and 2009], and placement (side-banded N and seedrow-placed N, using knives to create 2 cm wide band), plus a zero-N control, on seedling emergence, seed and straw yield, protein concentration (PC) in seed, and N uptake in seed and straw. For both crops, side-banded N had no detrimental effect on seedling emergence compared to the zero-N control for all rates and sources. Seedrow-placed ESN had little or no effect on seedling emergence of wheat or canola. Conversely, seedrow-placed urea, SuperU or AgrotainU reduced seedling emergence for wheat at the 80 and 120 kg N ha−1rates and reduced canola seedling emergence substantially at all rates, but particularly at the 80 and 120 kg N ha−1. Seed yield and N uptake were generally greater with ESN than urea and also SuperU or AgrotainU, when the fertilizers were seedrow-placed at high N rates. The findings suggest the effectiveness of ESN in providing greater seedrow-placed N application options for producers. [ABSTRACT FROM AUTHOR]

Interactive effects of zinc (Zn) × nitrogen (N) was investigated in field experiment on wheat (Triticum aestivumL., cv. ‘Saleem-2000’) at the Research Farm of KPK Agricultural University Peshawar during winter 2006–2007. The experiment consisted of four levels of N (0, 50, 100 and 100 kg N ha−1) as main plots, and six levels of Zn (0, 3, 6, 9, 12 and 15 kg Zn ha−1) as sub plots. Application of 150 kg N and 15 kg Zn ha−1resulted in the improved growth, highest yield components as well as the highest grain yield (4044 kg ha−1) and straw yield (5067 kg ha−1) of wheat. It is concluded from the results that combine application of 150 kg N +15 kg Zn ha−1could increase wheat productivity in the study area. [ABSTRACT FROM PUBLISHER]

Nitrogen (N) and phosphorus (P) deficiencies are major yield limiting factors in many parts of the world. A greenhouse experiment was conducted to study the effects of both N and P deficiency on morphological and physiological responses of wheat cultivars with and without purple coleoptiles in three types of soils. Before the 3-leaf stage, cultivar ‘Jagger’ with greenish coleoptile showed typical green color in leaves even if grown in soils known to be deficient in N and P. After 3-leaf stage, however, ‘Jagger’ grown in the same soils exhibited purple on leaves, which was considered a typical symptom of P deficiency. Before 3-leaf stage, cultivar ‘2174’ with purplish coleoptile showed purple on the tips of leaves even if grown in a soil not deficient in P, indicating that the leaf purple color is genetically controlled. Pre-plant P but not N fertilizer application could alleviate the purple severity of young seedlings (before 3 leaf stage). Top-dressing N fertilizer could alleviate the purple severity, but top-dressing P fertilizer could enable the severe purple leaves to return green at older seedlings (5–6 leaf stage), indicating that N and P had different effects on the morphological phenotype. There was a correlation between the purple severity and leaf chlorophyll readings, and N and P accumulation. The various responses of the cultivars to N and P deficiency resulted in significant differences in tiller occurrence and shoot and root dry matter production. Purple coloration is not only a visible symptom due to P deficiency but also a phenotype that can be used to diagnose N deficiency in wheat seedlings. [ABSTRACT FROM PUBLISHER]

Effects of salt [sodium chloride (NaCl): sodium sulfate (Na2SO4)] and alkali [sodium bicarbonate (NaHCO3): sodium carbonate (Na2CO3)] stresses on biomass and the contents of organic acids (OAs) components in wheat shoots and roots were compared. Both stresses inhibited the growth of wheat seedlings, the effect on roots biomass was higher than that on shoots, and more severe for alkali than for salt stress. Compared to salt stress, OAs are the special physiological responses of wheat seedlings to alkali stress. The total OAs contents in shoots increased significantly with increasing alkalinity, but only increased as alkali stress supply increased from 0 to 80 mM in roots, then decreased. Roots were more sensitive than shoots responding to alkali stress. High alkalinity destroyed cell membrane of root leading to organic acids efflux from roots. Among the OAs components, citrate and malate were the key components in wheat shoots and roots when responding to alkali stress. [ABSTRACT FROM AUTHOR]

□ Effects of different arsenic (As) concentration (0–30 mg L−1) on seed germination, root tolerance index, relative shoot height, root and shoot biomass, photosynthetic pigments and arsenic accumulation in two wheat varieties were investigated. Low concentrations of arsenic (0–2.5 mg L−1) stimulated germination percentage, shoot and root elongation, plant biomass as well as chlorophyll content as compared with control, however, these factors all decreased gradually at high concentrations of arsenic (5–30 mg L−1). ‘Zarin’ variety had a significantly higher tolerance to arsenic than ‘Sardari.’ Arsenic accumulation by plants root and shoot increased with the increasing arsenic concentrations in medium, which ‘Zarin’ had a higher ability to absorb and translocate arsenic to the shoots. Root accumulated more arsenic than shoot. The similar trend of chlorophyll content and wheat growth under different arsenic concentration suggesting that arsenic toxicity affects the photosynthesis which ultimately results in the reduction of wheat growth and yield. [ABSTRACT FROM AUTHOR]

Germination and seedling emergence are critical stages in plant growth cycle due to their effect on crop stand and eventual crop yield. In the present investigation, the effects of increasing applications of sodium chloride (NaCl) on germination, seedlings establishment at early growth stages, and respiration were studied in 20 wheat lines/cultivars. Seeds were germinated and grown in black covers using distilled water as control. NaCl was applied at concentrations of 8 and 16 dS m−1for 48 hours. Experimental design was factorial using completely randomized design with three replications. Seedling respiration was expressed as the difference between initial seed weight and seedling dry weight after 48 hours. Significant differences were found among lines/cultivars in terms of plumule and radicle length under salt stress conditions. Salt stress inhibited plumule growth and length more than radicle length. ‘Chamran’, ‘Yavarous’, ‘83-3’, ‘Taro3’, ‘Cross Boullani’, ‘Cross Aadl’, and ‘Dabira’ cultivars showed higher tolerance to NaCl treatment during the germination and showed the highest germination percentages. Maximum and minimum respiration rates were obtained in ‘Falat’ and ‘D81-17’, respectively. Differences among lines/cultivars in terms of respiration rate indicated that genetic variations exist among wheat lines/cultivars. It was also found that seedling respiration decreased as salinity level increased. These results suggest that at early growth stages, lines/cultivars with higher respiration rate have accelerated seedling growth. It was concluded that the seedling respiration rate might be used as a useful criterion in selection of wheat tolerant lines/cultivars to salt stress. [ABSTRACT FROM PUBLISHER]

The experiment was conducted on a farmer's field near Bhavnagar (Gujarat, India) during theRabiseason of 2008–2009 to study the effect of foliar applications ofKappaphycus alvareziiandGracilaria edulissap on growth and yield response of wheat var. ‘GW 496’. Three foliar sprays of both saps were applied at the rate of 2.5, 5.0, 7.5, and 10.0% (v/v) along with water as a control at different stages of the crop. It was found that yield of grain was increased significantly by 19.74% and 13.16% for plants receiving 7.5% and 5.0% concentrations ofK. alvareziiandG. edulissap, respectively, over control. The increase in yield was attributed to increases in the number of spike, spike weight, spike length and 100 seed weight. Foliar applications ofK. alvareziisap at 7.5% increased nutrient contents in grains from 7.91% (K) – 31.82% (S) whereasG. edulissap increased nutrient content 5.72% (N) – 37.54% (Mg). [ABSTRACT FROM PUBLISHER]

This work evaluated the effect of cadmium (Cd) on the physiological responses of corn (Zea Mays L.) and wheat (Triticum aestivum L.) to iron (Fe) deficiency. For this purpose, seedlings of corn and wheat were cultivated under controlled conditions, plants were grown in different strength Hoagland's solutions for one month. In the fifth week, some seedlings were still in full strength Hoagland's solution (+Fe) and others were in full strength Hoagland's solutions without iron (−Fe). The plants were exposed to different cadmium (Cd) concentrations for four days. The plant chlorophyll content of young leaves, Fe and Cd content in shoots and roots, biomass production, and phytosiderophores (PS) release by roots were assessed. Results showed that Cd decreased the chlorophyll content of young leaves, accompanied by a significant shoot and root biomass reduction for Fe-deficient and Fe-sufficient wheat and corn across all Cd treatments. However, chlorophyll content and shoot and root biomass of Fe-deficient wheat and corn were lower than Fe-sufficient plants at different Cd concentrations. Iron-deficiency induced Cd accumulation compared to Fe-sufficient in wheat and corn; however, a depressive effect of Cd on iron acquisition in shoots and roots of Fe-deficient and Fe-sufficient wheat and corn across all Cd treatments was observed. Cadmium also inhibited PS release in Fe-deficient and Fe-sufficient wheat and corn. Iron-deficient PS release was higher than Fe-sufficient corn and wheat across all Cd treatments. These results suggested that Cd might reduce capacity of plants to acquire iron from solution by inhibiting PS release. [ABSTRACT FROM PUBLISHER]

Past research about the efficiency of nitrogen application in winter wheat (Triticum aestivum L.) based on source and timing has produced inconsistent results. The majority of the literature used data from few locations over short time periods. This study used a unique data set of yields and nitrogen quantities from 2002–2009 at ten different locations in Oklahoma, USA. The objective of this research was to determine wheat yield response for granular pre-plant, uniform foliar topdress, and variable rate foliar topdress. Topdress liquid nitrogen had a 19% higher NUE than pre-plant urea, and was the most profitable source of nitrogen. [ABSTRACT FROM PUBLISHER]

Under certain conditions normalized difference vegetative index (NDVI) has low sensitivity; therefore red-edge position (REP) has been tested as an alternative vegetative index. The objective of this study was to determine if REP could be useful for detecting differences in N status for winter wheat compared to NDVI. A spectrometer, and the SPAD meter were used to measure N status. Sensitivity to plant N response and different growth stages was found for NDVI and REP, but NDVI sensitivity tended to decrease as N rate increased and REP sensitivity tended to increase with increased N rate and advancing growth stage. Both NDVI and REP were linearly correlated at all growth stages (r2 = 0.85). REP and SPAD meter readings were highly correlated (r2 = 0.62) as were NDVI and SPAD (r2 = 0.56). Overall, REP and NDVI sensitivity at high plant biomass were similar for winter wheat. [ABSTRACT FROM AUTHOR]

Indirect sensor-based measurements have made on-the-go by-plant recognition possible. This in turn has enabled high resolution by-plant management. The objective of this study was to estimate final grain yield of each corn (Zea mays L.) plant by collecting the normalized difference vegetation index (NDVI), plant height, and distance between plants at the 8-leaf growth stage (V8). The NDVI readings were collected every 1.2 cm in rows 15 to 30 m in length, and average NDVI per plant was calculated by assuming each plant occupied half the distance between it and its neighbors and calculating an average NDVI value within that respective area. First, an equation was developed to calculate the distance occupied by each plant. Then plant height was used in an equation to estimate competition among plants. A combined model employing plant height, area occupied, and NDVI were used to successfully predict by-plant corn grain yields at V8. [ABSTRACT FROM PUBLISHER]

The reduction in tiller number is a major reason for a decrease in grain yield of wheat. Thus, we hypothesize that the limiting growth of tillering of wheat plant under saline conditions may be due to a different distribution of ions among tillers, which may be tested by tiller removal. Two contrasting spring wheat (Triticum aestivum L.) genotypes were subjected to five levels of detillering treatments under saline or non-saline conditions grown in a greenhouse. Sodium (Na+), potassium (K+), calcium (Ca2+), chloride (Cl−), and nitrate (NO3 −) concentrations in the top leaves of tillers were determined at plant maturity. Regardless of genotypes, the moderate salinity significantly increased the Na+ and Cl− concentrations in the top leaves and the decreased NO3 − in the mainstem, subtillers and whole plant. Potassium and Ca2+ concentrations in leaves were not affected or slightly increased by salinity. Under moderate salinity, Na+ and/or Ca2+ concentrations in mainstem, subtillers and the whole plant were increased with a decrease in tiller removal for both genotypes, while there was almost no effect of tiller removal on Cl− and NO3 − concentration. The tiller removal increased the tolerance of wheat to tissue Na+ content, especially for the salt sensitive genotype. Thus, the salt-specific effects in wheat plant could be alleviated by fewer tillers per plant through the removal for the salt-sensitive genotype. However, our study did not show the competition for the mineral nutrients among tillers under saline conditions. Thus, we speculate that there is a competition for photoassimilates among the tillers under saline conditions, especially for the salt sensitive genotype, which needs to be investigated further. [ABSTRACT FROM PUBLISHER]

Mycorrhizal infection enhances phosphorus (P) nutritional status of plants under P-deficient soil condition. The yield responses of wheat to sulfur (S) alone, phosphorus (P) alone, and combined application of sulfur and phosphorus in mycorrhizal and non-mycorrhizal treatments in calcareaous non-sterilized Karaburun soil (sub-group Typic Xerorthent) were investigated. The elemental sulfur enhanced the mycorrhizal efficiency that resulted in increased shoot, root, and grain yield dry matter in comparison to mycorrhiza treatment alone. This new finding to increase the efficiency of the mycorrhizae by the addition of 100 mg kg−1 elemental sulfur to the soil suggests that elemental sulfur may play an important role for the ecologic agriculture. It can be specifically important for increasing the efficiency of mycorrhizal infection in well-aerated P deficient soil. [ABSTRACT FROM PUBLISHER]

We characterized varying capacity of two wheat cultivars (‘Brookton’ and ‘Krichauff’) and white lupin to acquire and utilize phosphorus (P) from different P resources [P0, rock phosphate, composted rock phosphate, phytate and soluble P) at 200 mg P kg−1 soil]. In all three genotypes, shoot P concentration and content were highest in the phytate treatment and lowest in P0. Roots of wheat cultivars exuded only traces of organic acid anions, whereas lupin root exudates contained high concentration of citrate. Phosphorus utilization efficiency (PUTE) was highest in P0 and lowest in the phytate treatment for all three genotypes. Phosphorus acquisition efficiency (PACE) ranged from 1 (‘Brookton’ in P0) to 355% (‘Brookton’ supplied with phytate). In conclusion, the availability of P in rock phosphate was not influenced by microbe and organics supplementation in the composting process and wheat cultivars were not as efficient as lupin in using P from sparingly soluble P sources. [ABSTRACT FROM PUBLISHER]

A key aspect of any sulfur (S) availability indicator is its stability throughout the crop cycle. Nine experiments were conducted with the objective to evaluate the stability of the nitrogen (N):S ratio in aerial biomass (W) in spring wheat, and to define the critical curve of S dilution. As the crop cycle progressed, a decrease (P < 0.05) in total N:S was determined. This lack of stability was explained by a lower S dilution in relation to N (P < 0.05). A decrease (P < 0.05) in N accumulation rate in relation to S was obtained as the crop cycle progressed, which points out that S accumulation in relation to N is later. A first approach was determined to the definition of the S dilution critical curve (Sc) from tillering beginning to stem elongation end (Sc = 0.37 W−0.169; r2 = 0.71 and n = 24). [ABSTRACT FROM AUTHOR]

Salinity stress is one of the important agricultural problems in the world. A factorial experiment based on completely randomized design with four replications was conducted to evaluate the effects of phytohormones (gibberellic acid and abscisic acid) on the activity of antioxidant enzymes (peroxidase, superoxide dismutase and catalase), rubisco activity and content, and proline in three wheat cultivars (Gascogen, Zagros, and Kuhdasht) under control and salinity stress (3.5 and 7 dS m−1). The results showed that salinity stress (3.5 and 7 dS m−1) decreased the activity of catalase, rubisco, carboxylase, but increased peroxidase, superoxide dismutase activity and proline content. Gibberellic acid caused 58.03% increased in rubisco carboxylase activity in Zagros at 7 dS m−1 in comparison with abscisic acid under salinity stress compared with the control plants in Kuhdasht. Activity of superoxide dismutase in Kuhdasht cultivar at 7 dS m−1 salinity level showed 76.43% increased in Gascogen under salinity stress compared with the control plants with gibberellic acid application. The highest proline content as an osmolyte was found in Zagros at 7 dS m−1 salinity level with abscisic acid (194 μmol g−1 DM) application. Peroxidase activity increased 83.31% and catalase activity decreased 61.27% compared with the control plants in Zagros. Gibberellic acid application significantly prevented reduction in rubisco content under salinity stress. In conclusion, increased in peroxidase and superoxide dismutase activity and proline content decreased the adverse effects of salinity stress on studied cultivars. Also, the foliage spray of gibberellic acid enhanced and improved the growth condition. In this experiment, Zagros cultivar showed more tolerance to salinity stress than the other two cultivars. [ABSTRACT FROM AUTHOR]

The objective of this study was to explore the potential of encapsulated calcium carbide (ECC) for improving performance of wheat (Triticum aestivum L.) under salinity stress. Three levels of salinity, 0, 1250 and 2000 mg kg−1 soil, were developed with sodium chloride (NaCl) salt, whereas ECC formulation was applied at 0, 15 and 30 mg kg−1 soil. The gas chromatography (GC) analysis revealed that 30 mg kg−1 soil of the formulation produced 154.12 μmols of ethylene (C2H2) and 8.44 μmols of C2H4 over a period of 60 days. The ECC decreased plant height, conductance (C), and transpiration (E) up to 7, 19 and 21%, respectively, over control. There was substantial elevation in net photosynthesis (Pn), number of tillers, grain yield and relative leaf water content (RWC) up to 14, 19, 17 and 3% with ECC over control. Both levels of ECC increased protein content significantly in wheat leaves up to 46 and 60% over control. Similarly, salinity increased the protein content up to 54 and 168% over control in the presence of ECC and salinity stress. SDS-PAGE protein profile of wheat leaves after the treatments of 15 mg ECC kg−1 soil and 2000 mg NaCl kg−1 soil showed a significant set of induced proteins of 8, 60 and 70 kDa. Similarly exposure of plants to 30 mg of ECC kg−1 soil and 2000 mg NaCl kg−1 soil resulted in the appearance of protein bands of 9, 10, 23 and 70 kDa. The induced levels of proteins detected at various levels of ECC and NaCl treatments correlated with its salinity tolerance. [ABSTRACT FROM PUBLISHER]