Stem Elongation Stage Research Articles

Root and Foot Rot Diseases of Winter Wheat Grown in Conventional and Organic Systems

The object of the study was fungous diseases occurring on roots, leave sheaths and stem base of winter wheat in the two opposing cropping systems (organic and conventional). The observations were made in vegetation periods (2007-2009) in the fields of winter wheat in northern Poland. Every year on each plot of compared farming systems root rot occurred (Fusarium spp., Gaeumannomyces graminis and other fungi). For the period of 3 years the degree of disease injury on the roots of winter wheat grown in the conventional system in the vegetation period increased, while in the organic one remained on pretty the same level. On average a lot more affected roots, especially in the flowering stage, occurred on the winter wheat grown in the conventional system. Fusarium foot rot (Fusarium spp.) developed on the wheat during the entire vegetation period. It was the most dangerous root and foot rot disease (the highest indexes of injury). The mean degree of disease injury on leave sheath was on pretty the same level in the two farming systems, although in investigated vegetation periods differed a lot, whereas at the bases of stems the pathogen was on the higher level on the wheat in the conventional system. Also eyespot (Tapesia yallude) developed in the entire vegetation period of the winter wheat, but its intensity was much lower than in case of fusarium foot rot. Leave sheaths of the wheat grown in the conventional system were slightly stronger affected than those grown in the organic system. In the flowering stage the intensity of the disease in both farming systems became equal, while in the wax maturity it was considerably higher in the conventional system. Sharp eyespot (Rhizoctonia spp.) appeared relatively late and occurred only in two years of investigation. The intensiveness of the disease was definitely higher on the organic plots. Among the affected roots, taken in the stem elongation stage, from the organic system 28 cultures of fungi were isolated, and from the conventional one 24 colonies. Cereals pathogenic fungi amounted 35.8% of isolates obtained from the organic system and as many as 66.7% from the conventional system. Among the affected roots, taken in the flowering stage, from the organic system 68 cultures of fungi were isolated in all, and from the conventional one 25 colonies. Cereals pathogenic fungi amounted 38.2% of isolates obtained from the organic system and 56.0% from the conventional system. Among the affected stem bases, taken in the wax maturity stage, from the organic system 56 cultures of fungi were isolated in all, and from the conventional one 52 colonies. Cereals pathogenic fungi amounted 48.4% of isolates obtained from the organic system and 53.6% from the conventional system. In the case of all root and foot rot diseases of wheat grown in the organic system, an advantageous influence of greater biodiversity and number of various fungi species living in root proximity was noticed as opposed to the conventional system.

Wplyw zroznicowanego nawozenia fosforem i potasem na zawartosc i pobranie makroskladnikow (N, P, K, Mg, Ca) przez pszenice ozima I Zawartosc makroskladnikow

The aim of the study carried out under field conditions was to evaluate the effect of differentiated phosphorus and potassium fertilization level on nutritional status of winter wheat at stem elongation (BBCH 31) and flowering (BBCH 65) development stages as well as on macronutrient contents in yield obtained (grain and straw). The research was conducted in 2007-2010, within an individual agricultural holding, on lessive soil with medium and high richness in potassium and phosphorus, respectively. The contents of nitrogen, phosphorus, potassium, magnesium and calcium in wheat changed depending on the organ assessed and plant development stage. At BBCH 31, regardless fertilization level, the plants observed were malnourished with potassium, phosphorus and calcium and at the control site – also with nitrogen. Furthermore, there were found significant correlation relationships among the contents of nutrient pairs: nitrogen-potassium, nitrogen-phosphorus, nitrogen-magnesium and nitrogen-calcium. The content of nitrogen in wheat grain and straw differed mainly due to weather conditions during the study. Irrespective of the years of observation, differentiated rates of P and K applied had no significant effect on N accumulation in wheat at full ripening stage. In contrast to nitrogen, the level of P and K fertilization significantly differentiated the contents of phosphorus, potassium and magnesium in wheat grain and straw. In case of calcium, the effect of fertilization factor was indicated only as regards the content of this nutrient in grain.

Lodging resistance of winter wheat (Triticum aestivum L.): Lignin accumulation and its related enzymes activities due to the application of paclobutrazol or gibberellin acid

Lodging is an important constraint limiting wheat yields and quality by bending or breaking stems on wheat (Triticum aestivum L.) production worldwide. This study was conducted to determine whether lignin accumulation and lodging resistance of winter wheat could be affected by application of paclobutrazol (PP333) or gibberellin acid (GA3) at stem elongation stage (DC 3.0). Two winter wheat cultivars, Jimai22 (lodging-tolerant cultivar; JM22) and Shannong16 (lodging-susceptible cultivar; SN16), were used to investigate the effect of exogenous hormones on wheat lodging behavior, lignin accumulation in culms and its relation to lodging resistance. Results showed that application of PP333 significantly reduced plant height and the length of basal second internode, while GA3 had the opposite effect. Lignin accumulation was positively and significantly correlated with the breaking strength of internode and culm lodging resistance index (CLRI). PP333 significantly increased lignin accumulation and its related enzymes activities in the basal second internode, and also increased the diameter, wall thickness, filling degree of the internode, thus the breaking strength and lodging resistance of wheat increased. Whereas, GA3 caused opposite effect on those characteristics. These results suggested that the exogenous PP333 or GA3 application significantly changed the risk of lodging occurred not only by altering the plant height but also by altering the physical strength of the basal part of the culm internode, especially, altering the lignin accumulation and its related enzymes activities in basal internode.

Does a mixture of old and modern winter wheat cultivars increase yield and water use efficiency in water-limited environments?

Use of mixtures of cultivars is an alternative to a monocultural crop and is considered one option to reduce the risks for producers. The objective of this study was to evaluate the grain yield and water use efficiency of a range of proportions of two winter wheat cultivars – an old landrace (Pingliang 40, PL) and a modern cultivar (Changwu 135, CW). Field experiments were conducted in 2004–2005 and 2005–2006 at Changwu Agricultural Research Station on the Loess Plateau of China. Along with pure stands of each genotype, four mixed stands, 20% PL and 80% CW (PL2:CW8), 40% PL and 60% CW (PL4:CW6), 60% PL and 40% CW (PL6:CW4), 80% PL and 20% CW (PL8:CW2), were established in the first year and a single mixture of 50% PL and 50% CW (PL5:CW5) was established in the second year. The grain yield of the mixtures fell between the yields of the respective monocultures under mild drought condition in 2005, while the yield of PL5:CW5 was not significantly different from that of the modern cultivar, CW, but higher than that of the landrace PL under the more unfavorable conditions (moderate drought) of 2006 (P<0.05). At the same proportions in the mixture, greater grain yield in PL than that in CW was associated with the higher spike density, higher grain number and larger grains. In 2005, the water use efficiency for grain (WUEg) of CW was significantly higher than that of PL, while the WUEg of the mixtures, except PL8:CW2, was intermediate between the WUEg of the two monocultures. In 2006, the WUEg of PL5:CW5 was higher than both PL and CW (P<0.05). In the mixtures, plant height increased in PL, but was reduced in CW, while the flag leaf area increased in both cultivars. The mixtures increased the aboveground biomass, the root biomass was reduced, so that the root-to-shoot biomass ratio (R:S) and root respiration of the mixtures were lower than that of the monocultures (P<0.05). For CW, the rate of leaf photosynthesis and leaf water use efficiency (WUEleaf) both decreased in mixture compared to the values in the monocultures. When the proportion in the mixture was the same, the rate of photosynthesis of the flag leaf and WUEleaf of PL was significantly greater than CW. In 2006, the root biomass in the PL5:CW5 mixture decreased by 29% and 17% (P<0.01) in the upper soil layer (0–0.4m) and increased by 70% and 99% (P<0.01) in the deep soil layer (0.6–1.0m) in PL and CW, respectively, compared with the individual cultivars in pure stand. The mixtures had reduced water use before stem elongation, but increased water use from deep soil layers after anthesis. These results indicate that under unfavorable conditions, mixtures offer benefits in conserving soil water before stem elongation, and may provide opportunity for greater niche exploitation and more effective resource use efficiency, especially the extraction of water deep in the soil profile. We suggest that the use of a mixture of cultivars in a serious drought season will ensure greater availability of water after stem elongation stage, resulting in higher yields and WUEg than in cultivars grown as a monoculture.

Hyperspectral canopy sensing of paddy rice aboveground biomass at different growth stages

Normalized Difference Vegetation Index and Ratio Vegetation Index obtained with the fixed band GreenSeeker active multispectral canopy sensor (GS-NDVI and GS-RVI) have been commonly used to non-destructively estimate crop growth parameters and support precision crop management, but their performance has been influenced by soil and/or water backgrounds at early crop growth stages and saturation effects at moderate to high biomass conditions. Our objective is to improve estimation of rice (Oryza sativa L.) aboveground biomass (AGB) with hyperspectral canopy sensing by identifying more optimal measurements using one or more strategies: (a) soil adjusted Vegetation Indices (VIs); (b) optimized narrow band RVI and NDVI; and (c) Optimum Multiple Narrow Band Reflectance (OMNBR) models based on raw reflectance, and its first and second derivatives (FDR and SDR).Six rice nitrogen (N) rate experiments were conducted in Jiansanjiang, Heilongjiang province of Northeast China from 2007 to 2009 to create different biomass conditions. Hyperspectral field data and AGB samples were collected at four growth stages from tillering through heading from both experimental and farmers’ fields. The results indicate that six-band OMNBR models (R2=0.44–0.73) explained 21–35% more AGB variability relative to the best performing fixed band RVI or NDVI at different growth stages. The FDR-based 6-band OMNBR models explained 4%, 6% and 8% more variability of AGB than raw reflectance-based 6-band OMNBR models at the stem elongation (R2=0.77), booting (R2=0.50), and heading stages (R2=0.57), respectively. The SDR-based 6-band OMNBR models made no further improvements, except for the stem elongation stage. Optimized RVI and NDVI for each growth stage (R2=0.34–0.69) explained 18–26% more variability in AGB than the best performing fixed band RVI or NDVI. The FDR- and SDR-based optimized VIs made no further improvements. These results were consistent across different sites and years. It is concluded that with suitable band combinations, optimized narrow band RVI or NDVI could significantly improve estimation of rice AGB at different growth stages, without the need of derivative analysis. Six-band OMNBR models can further improve the estimation of AGB over optimized 2-band VIs, with the best performance using SDR at the stem elongation stage and FDR at other growth stages.

THIS1 is a putative lipase that regulates tillering, plant height, and spikelet fertility in rice

Proper branching and successful reproductive growth is of great importance for rice productivity. Substantial progress has been made in uncovering the molecular mechanisms underlying tillering control and spikelet sterility. However, rice tillering is developmentally controlled, and how it is regulated coordinately with reproductive growth remains unclear. This study characterized a rice mutant, the most obvious phenotypes of which are high tillering, reduced height, and infertile spikelets (named this1). Similarly to the high tiller number and dwarf mutants in rice, the increased tiller number of this1 plants is ascribed to the release of tiller bud outgrowth rather than to increased tiller bud formation. In the this1 mutant, however, the accelerated rate of branching was delayed until the stem elongation stage, while other mutants lost the ability to control branching at all developmental stages. The seed-setting rate of this1 was less than half that of the wild type, owing to defects in pollen maturation, anther dehiscence, and flower opening. Histological analyses showed that the mutation in this1 resulted in anisotropic cell expansion and cell division. Using a map-based cloning approach, This1 was found to encode a class III lipase. Homology searches revealed that THIS1 is conserved in both monocots and eudicots, suggesting that it plays fundamental role in regulating branch and spikelet fertility, as well as other aspects of developmental control. The relative change in expression of marker genes highlighted the possibility that This1 is involved in phytohormone signalling pathways, such as those for strigolactone and auxin. Thus, This1 provides joint control between shoot branching and reproductive development.

On the relationship between N management and grain protein content in six durum wheat cultivars in Mediterranean environment

Grain protein has recently received attention in several countries because of a premium associated to increased protein concentration (PC) in grains. Nitrogen (N) fertilizer management with its timing of application and rates plays a crucial role in increasing PC. The objectives of the present study were to: (1) quantify the effects of different N fertilizer rates and timing of application on grain yield and grain protein of six durum wheat cultivars, and (2) identify the best cultivar in terms of net return, yield, and protein content in typical pedo-climatic condition of southern Italy. The field experiments were conducted in Foggia during three growing seasons (2002–2003, 2003–2004, and 2004–2005). Results from this study showed that N application at sowing did not influence the cultivars performance. N applied at stem elongation increased yield and protein content provided there is adequate soil water for N uptake. In absolute terms, the best combination was the cultivar Svevo managed using 104 kg N ha−1 split between tillering and stem-elongation stage. The excessive N splitting reduces yield and does not provide any improvement in terms of protein content.

The interactive effects humic acid application and several of nitrogen fertilizer on remobilization star wheat

In order to study the effect of the application of Humic acid and different levels of nitrogen on remobilization, production, and yield of star wheat a field experiment was carried out in the region of Viss in the form of split plot and randomized complete block design with four replications in crop year of 2011-2012. Main plots included various levels of nitrogen fertilizer (N0=50, N1=100, and N3=150 kgNha-1) and subplots included the application of Humic acid (H0= lack of Humic acid, H1=foliar spraying at stem elongation stage, H2=foliar spraying at reproductive stage).Results indicated that the effect of nitrogen and Humic acid on leaf area index, grain yield, rate of remobilization, share of remobilization, rate of photosynthesis and share of photosynthesis was significant. The highest amounts of leaf area index, grain yield, remobilization rate, current photosynthesis rate and share were obtained in treatment of 150 kgNha-1. The highest leaf area index, grain yield, remobilization rate, current photosynthesis rate and share were obtained at foliar spraying at reproductive stage. In examining the interactive effect of nitrogen and humic acid on leaf area index, remobilization rate, remobilization rate and share, the difference was significant. Also, at level of 150kgNha-1 the difference was significant for grain yield and current photosynthesis share at foliar spraying at reproductive stage but the difference was not significant at level of 100 kgNha -1 at foliar spraying at stem elongation stage. Therefore, for economical benefits, the application of 100 kgNha-1 along with humic acid foliar spraying at stem elongation stem is recommended.

Real-time PCR quantification and spatio-temporal distribution of airborne inoculum of Mycosphaerella graminicola in Belgium

Two kinds of propagules play a role in Mycosphaerella graminicola dissemination: splash-dispersed pycnidiospores and airborne sexual ascospores. A method based on real-time polymerase chain reaction (PCR) assay and using Burkard spore traps was developed to quantify M. graminicola airborne inoculum. The method was tested for its reliability and applied in a spore trap network over a 2-year period in order to investigate the spatio-temporal distribution of airborne inoculum in Belgium. At four experimental sites, airborne inoculum was detected in both years. A seasonal distribution was observed, with the highest mean daily quantities (up to 351.0 cDNA) trapped in July and with clusters detected from September to April. The first year of trapping, a mean daily quantity of 15.7 cDNA of M. graminicola airborne inoculum was also detected in the air above a building in a city where the spatio-temporal distribution showed a similar pattern to that in the field. Mean daily quantities of up to 60.7 cDNA of airborne inoculum were measured during the cereal stem elongation and flowering stages, suggesting that it contributes to the infection of upper leaves later in the season. Most detection, however, tended to occur between flowering and harvest, suggesting significant production of pseudothecia during that period. Variations in mean daily quantities from 1.0 to 48.2 cDNA were observed between sites and between years in the patterns of airborne inoculum. After stem elongation, the quantities detected at a site were positively correlated with the disease pressure in the field. Quantities trapped at beginning of the growing season were also well correlated with the disease level the previous year. Multiple regressions revealed that some factors partly explain the daily variations of airborne inoculum.

Effects of Root Pruning on Non-Hydraulic Root-Sourced Signal, Drought Tolerance and Water Use Efficiency of Winter Wheat

Two pot experiments were conducted to study the effects of root pruning at the stem elongation stage on non-hydraulic root-sourced signals (nHRS), drought tolerance and water use efficiency of winter wheat (Triticum aestivum). The root pruning significantly reduced the root weight of wheat, but had no effect on root/shoot ratio at the two tested stages. At booting stage, specific root respiration of root pruned plants was significantly higher than those with intact roots (1.06 and 0.94 mmol g−1 s−1, respectively). The soil water content (SWC) at which nHRS for root pruned plants appeared was higher and terminated lower than for intact root plants, the threshold range of nHRS was markedly greater for root pruned plants (61.1-44.6% field water capacity) than for intact root plants (57.9-46.1% field water capacity). At flowering stage, while there was no significant difference in specific root respiration. The SWCs at which nHRS appeared and terminated were both higher for root pruned plants than for intact root plants. The values of chlorophyll fluorescence parameters, i.e., the effective photosystem II quantum yield (ϕPS II), the maximum photochemical efficiency of PS II (Fv/Fm), coefficient of photochemical quenching (qP), and coefficient of non-photochemical quenching (NPQ), in root pruned plants were significantly higher than in intact root plants, 7 d after withholding of water. Root pruned plants had significantly higher water use efficiency (WUE) than intact root plants in well-watered and medium drought soil, but not in severe drought condition. In addition, root pruning had no significant effect on grain yield in well-watered and medium drought soil, but significantly decreased grain yield in severe drought condition. In conclusion, the current study showed that root pruning significantly altered nHRS sensitivity and improved WUE of winter wheat in well-watered and medium drought soil, but lowered drought tolerance of winter wheat in severe drought soil. This suggests a possible direction of drought-resistance breeding and potential agricultural measure to improve WUE of winter wheat under semiarid conditions.

Wheat grain Cd concentration and uptake as affected by timing of fertilizer N application

Li, X., Ziadi, N., Bélanger, G., Yuan, W., Liang, S., Xu, H. and Cai, Z. 2013. Wheat grain Cd concentration and uptake as affected by timing of fertilizer N application. Can. J. Soil Sci. 93: 219–222. The effect of a single N application (120 kg ha−1) at seeding on wheat (Triticum aestivum L.) grain Cd concentration and uptake was compared with an equally split N application (seeding and the stem elongation stage) in a field experiment at 12 site-years. Averaged across all site-years, the single N application tended to reduce wheat grain Cd concentration (58 vs. 68 µg kg−1DM) and uptake (151 vs. 191 mg ha−1) compared with the split application. The Cd concentrations, however, never exceeded the maximum acceptable level for Cd in wheat grain. A single N application at seeding might reduce the risk of high grain Cd concentration in spring wheat.

Wheat grain Cd concentration and uptake as affected by timing of fertilizer N application

Li, X., Ziadi, N., Belanger, G., Yuan, W., Liang, S., Xu, H. and Cai, Z. 2013. Wheat grain Cd concentration and uptake as affected by timing of fertilizer N application. Can. J. Soil Sci. 93: 219-222. The effect of a single N application (120 kg ha-1) at seeding on wheat (Triticum aestivum L.) grain Cd concentration and uptake was compared with an equally split N application (seeding and the stem elongation stage) in a field experiment at 12 site-years. Averaged across all site-years, the single N application tended to reduce wheat grain Cd concentration (58 vs. 68 µg kg-1 DM) and uptake (151 vs. 191 mg ha-1) compared with the split application. The Cd concentrations, however, never exceeded the maximum acceptable level for Cd in wheat grain. A single N application at seeding might reduce the risk of high grain Cd concentration in spring wheat.

Effect of Growth Stage-Based Irrigation Schedules on Biomass Accumulation and Resource Use Efficiency of Wheat Cultivars

Climate and weather conditions greatly affect the performance of new wheat cultivars for yield and resource use efficiency. In order to know the effect of irrigation schedules based on growth stage (the most vital criterion in the region) on growth, yield and radiation use efficiency of wheat cultivars in Faisalabad conditions, a study was planned at Agronomic Research Area, University of Agriculture, Faisalabad during 2009-2010. Split plot design with irrigation levels in main plots and cultivars in sub-plots was implied. Irrigation levels were: IT = irrigation at tillering stage, ITS = irrigation at tillering and stem elongation stage, ISB = irrigation at stem elongation and booting stage and ITSBG = irrigation at tillering, stem elongation, booting and grain filling stage. Cultivars selected were: Faisalabad-2008, Lasani-2008, Miraj-2008, Shafaq-2006 and Chakwal-97. Irrigation treatment ITSBG gave higher grain yield (4.23 t·ha-1) followed by ISB (3.60 t·ha-1), however ITSBG was statistically similar to ISB in radiation use efficiency (RUE) for grain yield (RUEGY). Similarly the two treatments were statistically at par in maximum leaf area index, total dry matter (TDM) accumulation, cumulative photosynthetically active radiation (PAR), and RUETDM. Hence where less numbers of irrigations are available, irrigation at stem elongation and booting stage is suitable for achieving economic yield. Lasani-2008 produced maximum grain yield (4.37 t·ha-1) compared to other cultivars but it was statistically at par with Shafaq-2006 in plant height, TDM production and RUETDM. Depending on the availability, the two cultivars may be chosen under irrigated conditions of Faisalabad.

Competition between spring barley (Hordeum vulgare L.) and italian ryegrass (Lolium multiflorum Lam.) under different water supply conditions

A pot experiment with an additive design and three series was conducted to test competition between spring barley and Italian ryegrass under different soil moisture conditions. The experimental factors were as follows: 1. type of sowing – mixed sowing and pure sowing; 2. water supply – plants supplied with water to meet their full requirements and 50% water supply reduction. The study covered five phenological development stages (BBCH) of spring barley: emergence (10–13), tillering (22–25), stem elongation (33–37), heading (52–55), and ripening (87–91). The competitive effects were evaluated based on relative yield (RY), relative yield total (RYT), competitive balance (CB), and relative efficiency index (REI). Spring barley and Italian ryegrass competed for resources throughout the growing season. Competition intensity was found to increase until the heading stage, and it decreased towards the end of the growth cycle. More intense competition was observed under reduced water supply. Spring barley dominated over Italian ryegrass from the tillering stage to the ripening stage. In mixed populations, Italian ryegrass captured the available resources more effectively than spring barley from the stem elongation stage until the end of the growing season, particularly in the treatment with optimal water supply.

Effect of growth regulator Kelpak SL on the formation of aboveground biomass of Festulolium braunii (K. Richt.) A. Camus

A study on the cultivation of &lt;em&gt;Festulolium braunii&lt;/em&gt; cv. 'Felopa' was carried out using polyurethane rings with a diameter of 36 cm and a height of 40 cm, which were sunk into the ground to a depth of 30 cm and filled with soil material. In this experiment, Kelpak SL was used as a bioregulator. It consists of natural plant hormones such as auxins (11 mg in dm&lt;sup&gt;3&lt;/sup&gt;) and cytokinins (0.03 mg in dm&lt;sup&gt;3&lt;/sup&gt;). The experimental factors were as follows: A1-control; A2 – 20% solution of the growth regulator; A3 – 40% solution; and A4 – 60% solution. The preparation was applied to all three regrowths in the form of spray, at a rate of 3 cm&lt;sup&gt;3&lt;/sup&gt; ring&lt;sup&gt;-1&lt;/sup&gt;, at the stem elongation stage. The full period of this experiment was in the years 2010–2011. During this time, detailed investigations were carried out on aboveground biomass yield (g DM ring&lt;sup&gt;-1&lt;/sup&gt;), number of shoots (pcs ring&lt;sup&gt;-1&lt;/sup&gt;), leaf blade length (cm), width of the leaf blade base (mm), leaf greenness index (SPAD). The study showed a significant effect of the growth regulator on the formation of &lt;em&gt;Festulolium braunii&lt;/em&gt; biomass. However, its highest effectiveness was observed when the 60% solution was applied.

Plant growth and phenolic compounds in the rhizosphere soil of wild oat (Avena fatua L.)

The objectives of this study were to determine the pattern of dry matter (DM) accumulation and the evolution of phenolic compounds in the rhizosphere soil from tillering to the ripe seed stages of wild oat (Avena fatua L.), a widespread annual grassy weed. Plants were grown under controlled conditions and harvested 13 times during the growing season. At each harvest, shoot and root DM and phenolic compounds in the rhizosphere soil were determined. The maximum DM production (12.6 g/plant) was recorded at 122 days after sowing (DAS; kernel hard stage). The increase in total aerial DM with age coincided with reductions in the leaf/stem and source/sink ratios, and an increase in the shoot/root ratio. HPLC analysis shows production of seven phenolic compounds in the rhizosphere soil of wild oat, in order of their decreasing levels: syringic acid, vanillin, 4-hydroxybenzoic acid, syringaldehyde, ferulic acid, p-cumaric acid and vanillic acid. The seasonal distribution for the total phenolic compounds showed two peaks of maximum concentrations, at the stem elongation stage (0.71 μg/kg; 82 DAS) and at the heading stage (0.70 μg/kg; 98 DAS). Thus, wild oat roots exude allelopathic compounds, and the levels of these phenolics in the rhizosphere soil vary according to plant maturity.

Effects of drought stress on quantitative and qualitative yield and antioxidative activity of Bunium persicum

Drought stress is one of the growing concerns in agriculture management around the world. Adopting tolerant plants to drought conditions could be an appropriate approach to this problem. Bunium persicum is one of the most important medicinal plants of Iran and Turkey as well as neighbouring countries and has been forced into endangered plant status due to mismanagement of its wild habitats. An experiment was conducted in order to evaluate drought tolerance of Bunium persicum and the effects of drought on its essential oil qualitative properties. Two separate plans based on randomised complete block design were performed with 4 drought levels (irrigation after 60, 90, 120, and 150 mm of evaporation from an evaporation basin) and 3 replications. Drought treatments were applied after the stem elongation and flowering stages. Results indicated that applied drought treatments reduced yield and yield components of plants in both growth stages. Some differences were observed in yield components when plants were exposed to drought stress at different growth stages. The essential oil percentage of Bunium persicum was affected by drought conditions, and it was elevated along with increasing drought levels. Due to reduced seed yield, essential oil yield was significantly decreased. Antioxidative activity assessment of seed extracts revealed that drought had positive effects on antioxidant parameters, including 2'-diphenyl 1-picrylhydrazyl radical scavenging activity, hydrogen peroxide scavenging activity, and Fe-reducing power. Phenol content was also improved through applied drought treatments. In general, these results showed the high tolerance of Bunium persicum to drought and also revealed positive effects of drought on the antioxidative activities of plant seeds.

Effect of differentiated phosphorus and potassium fertilization on winter wheat yield and quality

This study was conducted in 2007-2010, on a farm near Œrem (south of Poznan, Poland). A field experiment was set up in a randomized block design with four replications for each combination tested. The effects of differentiated rates of phosphorous and potassium applied together with a fixed level of nitrogen and magnesium fertilization were investigated. During the experiment, the winter wheat grain yields were high and significantly different between both between fertilizer treatments and when compared with the control. Correlation analysis on relationships between grain yield and nutrient content in wheat leaves at the beginning of stem elongation stage (BBCH31) showed significant relationships for phosphorous, calcium, magnesium, zinc and manganese. Regression analysis proved that the content of zinc in leaves at the BBCH31 stage was the main factor which determined winter wheat grain yield. Furthermore, mineral fertilization significantly increased the content of protein and gluten when compared with the control objects, whereas no significant differences were observed among the fertilized objects. Statistically significant relationships were found between leaf content of N, P, Mg, Zn and Mn at BBCH31 and the accumulation of protein and gluten in wheat grain. Protein and gluten in grain depended on the content of magnesium in leaves at the beginning of stem elongation stage. Weather conditions as a factor significantly influenced grain size uniformity while mineral fertilization had no influence on this trait.

Effects of boron fertilization of spring cereals depending on application methods

The study is a comparison of effects produced by boron fertilization applied to spring barley and oats, grown on light soil, low in available boron, in relation to the application method (pre-sowing, top dressing, foliar applications) and rates of the element. The study was carried out as a three-year series of one-year, two-factor strict field trials (the splitplot design). It has been demonstrated that top dressing with boron applied to soil at the tillering stage as well as foliar fertilization during the stem elongation stage can significantly improve yields. Grain of both cereals from the control plots showed symptoms of insufficient boron nutrition, which were absent when boron fertilization had been applied. Presowing fertilization, although not affecting the yields, improved the supply of grain with boron. Differences between the cereal species were found in terms of boron concentrations in vegetative organs of the cereals and in their response to higher availability of this nutrient. Compared to spring barley, oats was characterised by a much higher content of boron in vegetative parts and was more responsive to increased concentrations of boron in soil.

Effects of irrigation treatment and Azospirillum inoculation on yield and yield component of black cumin (Nigella sativa L.)

The aim of this study was to investigate the effects of terminating irrigation at different developmental stages and Azospirillum inoculation on quantitative yield of black cumin (Nigella sativa L.). The experiment was conducted during the growing season of 2011 at the Experimental Station of the Research Institute of Forest and Rangeland, Damavand, Iran. Treatments consisted of irrigation with three levels (W1 = normal irrigation from emergence to harvest (control), W2 = irrigation terminated at the start of budding and W3 = irrigation terminated at the start of flowering) and Azospirillum inoculation at four levels (A1 = non-inoculated, A2 = seed inoculated and A3 = spraying on the plant base at stem elongation stage, A4 = seed inoculated + spraying on the plant base at stem elongation stage). The present results have shown that irrigation terminated at the start of budding caused significant reduction in number of follicles per plant, biomass production and seed yield. Azospirillum had positive effects in all measured traits, especially when it used at two times (at seed inoculated + spraying on the plant base at stem elongation stage or A4 treatment).