The incidence of fusarium foot-rot occurrence on the winter wheat cultivars Roma and Sakwa was examined in the years 2001–2003. Strict plot experiments were set up by the method of random sub-blocks in Tomaszkowo near Olsztyn. Fungicides were applied on the growing plants during the periods of shooting and heading. The control plots were sprayed with water. The sanitary state of leaf sheaths was evaluated at heading phase (GS 55). The symptoms of fusarium foot-rot were examined at the phase of milky maturity (GS 75) and waxy maturity of grain (GS 87). The study aimed at assessing the average index of infection of the winter wheat stem base caused by the species of Fusarium genus, assessing the vulnerability of the Roma and Sakwa cultivars to these fungi and determining the effectiveness of pesticides in control of fusarium foot-rot. Fusarium foot-rot (Fusarium spp.) of winter wheat dominated on the winter wheat stem base. Most of the examined stems were severely infected. The Roma cultivar was more susceptible to infection by Fusarium fungi than the Sakwa cultivar. The effectiveness of fungicides in controlling fusarium foot-rot on the winter wheat was satisfactory, but largely depended on the cultivar and weather conditions. Mirage 450EC and Sportak Alpha 380EC fungicides were the most effective. The species F. culmorum and F. avenaceum dominated in the fungal populations colonizing the stem base of winter wheat with visible symptoms typical of fusarium foot-rot.
Wheat grain discoloration, a worldwide disease that lowers grain quality and decreases grain yield, does not have a single etiology. It has been proposed that it is a consequence of an abiotic mechanism, a response to environmental conditions or enzymatic activity. It has also been suggest that it is a biotic mechanism, a fungal infection principally by Alternaria spp. and Bipolaris sorokiniana. The present work was carried out to analyze the possible etiology of this disease in nine durum wheat genotypes from two localities of southern Buenos Aires province (Argentina) on two sowing dates. Incidence (percentage of grain discoloration) was recorded and mycobiota associated with this pathology was registered following ISTA rules. Peroxidase activity in an extract obtained from grains belonging to genotypes of the locality that showed the highest incidence was measured.
The incidence among genotypes, localities and sowing dates varied, although the genotypes with the higher and lower values of incidence were the same for all the variables tested. The fungus Alternaria spp. was isolated the most frequently followed by Fusarium spp., while Bipolaris sorokiniana was found the least frequently. Peroxidase activity showed that all the treatments had similar levels of enzymatic activity, but there was no clear differentiation between controls either between genotypes with the lowest or the highest incidence values. This suggests that peroxidase activity did not have a clear relationship with grain discoloration. In this research, it is presumed that fungal infection is the main cause of this disease.
Nanotechnology is a manipulation of nature that has emerged through the use of basic sciences, material science and engineering at the nano-scale. The interaction between biological environment and nanoparticles-nanoparticles or nanoparticles-organic materials is not yet well-understood. The toxic effects of nanoparticles on plants were investigated and it was proved that they caused morphological and physiological changes in plants. This study aimed to determine the effects of TiO -TiO2Ag nanoparticles, and co-application of EDDS-TiO2Ag nanoparticles alone, co-application of ZnO nanoparticles- Ag nanoparticles on seed germination, seedling vigor, radicle and plumule elongation of two different wheat species. In the experimental stage, ten seeds were placed in petri-dishes with a double layer of fi lter paper which was used as an inert material. Then 5 mL of TiO2Ag, ZnO+TiO2Ag, and EDDS+TiO2Ag suspensions were added to every petri dish. Results showed that the maximum SVI was determined at the concentration of 50 mg∙L-1 TiO2 Ag+EDDS for bread wheat and the minimum SVI was observed at 100 mg∙L-1 TiO2Ag nanoparticles concentration for durum wheat. The effect of both nanoparticles-nanoparticles interaction and the other chemicals-nanoparticles interaction on the ecosystems should be evaluated.
The objective of the study was to determine the effect of leaf wetness period and air temperature on development of disease symptoms caused by Puccinia recondita on winter wheat. The experiments were carried out in growth chamber at the Institute of Plant Protection in Poznań. Seedlings of a susceptible winter wheat cultivar Mikon, were artificially inoculated with urediniospores of P. recondita and incubated in temperature of 15 and 20°C. The period of duration of leaf wetness varied from 2 to 14 hours. Disease symptoms on seedlings at 20°C appeared 7 days after inoculation. Reduction of temperature to 15°C resulted in the elongation of latency period to 8 days. The relationship between leaf wetness period and disease symptoms severity was also observed. The gratest number of urediniospores in both tested temperatures were observed on plants exposed to 14 hours of leaf wetness. In temperature of 20°C 4 hours of wetness duration was enough to guarantee infection and the appearance of P. recondita pustules, whereas in 15°C at least 10 hours of wet period was needed to cause disease symptoms development. The experimental results were used to produce two equations describing relation between leaf wetness and symptoms development in tested temperatures.
Plants under attack of herbivores can emit increased amounts of volatile compounds from their leaves. Similarly, mechanically-injured plants can emit volatile chemicals that differ both quantitatively and qualitatively from undamaged plants. In this experiment, mechanical injury increased the release of the secondary metabolites linalool (3,7-dimethyl-1,6-octadien-3-ol) and linalool oxide (5-ethenyltetrahydro-2-furanmethanol) by wheat plants. The amounts released varied significantly with injury type and the period of time after injury. The time interval for the volatile collection within the photophase also influenced the amount collected for each day. The increased emission of these compounds, as a result of injury, may be explained as a defense mechanism against wounding. The role of these plant volatiles can be further investigated in the context of plant response to mechanical injury, within the broader context of all types of injury.
Cereal cyst nematodes (Heterodera spp.) are distributed globally and cause severe production losses of small grain cereals. To investigate the occurrence of cereal cyst nematodes in wheat-growing areas of Algeria, a survey was conducted and 27 cereal cyst nematode populations were collected. The populations were initially identified based on their morphological and morphometric characters, followed by molecular methods using speciesspecific primers, complemented by ITS-rDNA sequences. The morphological and morphometric features of second-stage juveniles (J2s) and cysts supported the presence of three Heterodera species: H. avenae, H. filipjevi and H. hordecalis. All morphological values of these distinct populations were very similar to those previously described for these species. Using species-specific primers for H. avenae and H. filipjevi, the specific bands of 109 bp and 646 bp confirmed the morphological identification of both species, respectively. In addition, the internal transcribed spacer (ITS) regions were sequenced to study the diversity of the 27 populations. These sequences were compared with those of Heterodera species available in the GenBank database (www.ncbi.nlm.nih.gov) and re-confirmed the identity of the species. Nineteen sequences of ITS-rDNA were similar (99–100%) to the sequences of H. avenae published in the GenBank, six sequences were similar (99–100%) to H. hordecalis, and two were similar (98–99%) to H. filipjevi. The results of this study are of great value to breeding programs and extension services, where they will contribute to the design of control measures to keep damaging nematodes in check.
Redroot pigweed (Amaranthus retroflexus L). is a broadleaf weed in autumn crop fields in Russia. Four field experiments were performed in Stalskiy region, southern Russia in two growing seasons, 2016 and 2017, to investigate the effects of postemergence applications of applied alone or in tank mixtures in winter wheat cultivars Tanya and Bagrat. Redroot pigweed control was greatest with tribenuron and all herbicide treatments containing tribenuron. The lowest redroot pigweed control was with aminopyralid/florasulam (study 1) and triasulfuron (study 2), respectively, whereas redroot pigweed had intermediate responses to the other examined herbicides. Tribenuron plus fluroxypyr sprayed on wheat cultivar ‘Tanya’, and tribenuron plus triasulfuron on wheat cultivar ‘Bagrat’ resulted in increased wheat grain yields. Overall, tribenuron and herbicides containing tribenuron provided the most efficient redroot pigweed control compared with the other herbicides and consistently maintained optimal winter wheat yields. Tribenuron could ameliorate redroot resistance to herbicides in wheat fields in southern Russia.
Gene postulation is one of the fastest and most cost-effective methods for identifying seedling leaf rust resistance genes in wheat cultivars. Many researchers use this approach to identify Lr genes in wheat cultivars. The purpose of our research was to identify seedling leaf rust resistance genes in 20 wheat cultivars from different breeding centers of Russia, Ukraine and Germany. Forty-two near isogenic Thatcher lines and 10 Puccinia triticina isolates were used for gene postulation. When assessing the infection types to cultivars and lines, a scale was used, according to Oelke and Kolmer. In 20 wheat cultivars 19 Lr genes were postulated: 2c, 3, 10, 3bg, 3ka, 14a, 17, 18, 23, 25, 26, 30, 33, 40, 44, 50, B, Exch, Kanred. The most common for cultivars was the Lr10 gene. In five cultivars, showing high field resistance, most postulated seedling genes (Lr2c, Lr3, Lr10, Lr14а, Lr26, Lr33) were not effective in the adult stage. It is possible that resistance of such cultivars is associated with APR genes, the postulation of which requires an expansion in the number and spectrum of P. triticina isolate virulence. Most of the studied cultivars (60%) have recently been entered into the register (2015–2019) and in the field show a stable or moderately susceptible response to P. triticina infection, despite the fact that the Lr genes postulated in them were not effective in the adult stage. The data obtained indicated a variety of genotypes of the studied cultivars, as well as the tendency of breeders to use the effect of pyramiding ineffective genes, which can prolong the resistance of the cultivar. Annual monitoring of varieties is necessary in each region, especially when reacting with a medium susceptible type (MS), which may indicate the initial stage of resistance loss.
Scarcity of fresh water resources is the major constraint for agricultural development in Iran as in many other regions with arid and semi-arid climate. With the pressure on fresh water resources, the use of un-conventional water resources including brackish, saline and sewage water has received greater attentions in recent years. The objective of this study was to assess the impact of farmers' practices using saline groundwater on wheat yield and soil salinity in a Mediterranean cli-mate of Fars province in southern Iran. The study was carried out in several commercial wheat production regions for two years. Chemical analysis of irrigation waters, volume of applied irrigation water, electrical conductivity of soil saturation extract (ECe) and yield were measured in each field. General information on agronomic practices was also collected using a questionnaire. Results demonstrate that waters with salinities higher than what has been classified as “suitable for irriga-tion” are being used for the production of wheat crop. Analysis of wheat yield response to saline irrigation water showed that for water salinities up to 10.7 mS∙cm–1 (threshold value) variation in yield was relatively minor, above which wheat yield decreased at a greater rate. Root zone salinity profiles showed the effect of winter rainfall in reducing soil salinity. It is concluded that although acceptable yields are obtained with some of the highly brackish waters, over application of these waters would threaten the sustainability of crop production in the region.
Using in vitro androgenesis serves as a unique opportunity to produce doubled haploid (DH) plants in many species. More benefits of this biological phenomenon have kept these methods in the focus of fundamental research and crop breeding for decades. In common wheat (Triticum aestivum L.), in vitro anther culture is one of the most frequently applied DH plant production methods. The efficiency of in vitro wheat anther culture is influenced by many factors, such as the genotype, growing conditions, collection time, pre-treatments, and compositions of media and culture conditions. According to some critical review, the genotype dependency, low efficiency and albinism are mentioned as limitations of application of the anther culture method. However, some research groups have made significant efforts to diminish the effects of these bottlenecks. Due to the improvements, a well-established in vitro anther culture method can be an efficient tool in modern wheat breeding programs.
In the present study, the enrichment and isolation of textile effluent decolorizing bacteria were carried out in wheat bran (WB) medium. The isolated bacterium Providencia rettgeri strain HSL1 was then tested for decolorization of textile effluent in consortium with a dyestuff degrading fungus Aspergillus ochraceus NCIM 1146. Decolorization study suggests that A. ochraceus NCIM 1146 and P. rettgeri strain HSL1 alone re moves only 6 and 32% of textile effluent American Dye Manufacturing Institute respectively in 30 h at 30 ±0.2°C of microaerophilic incubation, while the fungal-bacterial consortium does 92% ADMI removal within the same time period. The fungal-bacterial consortium exhibited enhanced decolorization rate due to the induction in activities of catalytic enzymes laccase (196%), lignin peroxidase (77%), azoreductase (80%) and NADH-DCIP reductase (84%). The HPLC analysis confirmed the biodegradation of textile effluent into various metabolites. Detoxification studies of textile effluent before and after treatment with fungal-bacterial consortium revealed reduced toxicity of degradation metabolites. The efficient degradation and detoxification by fungal-bacterial consortium pre-grown in agricultural based medium thus suggest a promising approach in designing low-cost treatment technologies for textile effluent.
The aim of this study was to determine the effect of different zinc and iron concentrations in culture
medium on growth and development of maize and wheat seedlings in terms of their inoculation with bacteria of
Azospirillum genus. Maize and wheat in vitro cultures were inoculated, respectively, by strains of Azospirillum
lipoferum and Azospirillum brasilense strains. The experimental factor was the supplementation of the culture
medium with zinc (25, 200 and 600 mg·kg-1 of the medium) and iron (25, 200 and 600 mg·kg-1 of the medium).
Counts of bacteria from the Azospirillum genus were analysed and plant seedling growth and development as
well as the content of chlorophyll in plant leaf blades were monitored.
Zinc turned out to reduce strongly numbers of bacteria of the Azospirillum genus. Azospirillum brasilense
turned out to be particularly sensitive to elevated levels of this chemical element in the environment. The negative influence of increased quantities of zinc on cereal seedlings became apparent only after the application of
the highest concentrations of this metal in the medium (600 mg·kg-1), while quantities which did not exceed
200 mg·kg-1 exerted a stimulation effect on the mass of maize and wheat seedlings.
Iron added to the culture medium in quantities which did not exceed 200 mg·kg-1 did not reduce numbers of
bacteria of the Azospirillum genus; on the contrary, they stimulated their growth. However, at higher concentrations, this metal turned out to exert a strong negative impact on the chlorophyll content in leaf blades as well as
on the mass of maize and wheat seedlings.
The inoculation with bacteria of the Azospirillum genus exerted a positive influence on the mass increase of
maize and wheat seedlings and increased chlorophyll concentrations in leaf blades. At the same time, it contributed significantly to limiting or even levelling out the toxic impact of zinc and iron during the initial phases of
plant growth and development.
The effect of biopreparation Biochikol 020 PC on linear growth of mycelia of two Rhizoctonia isolates was tested under laboratory conditions along with that of fungicide Baytan Universal 19,5 WS for comparative purposes. Complete retardation of mycelial growth of both isolates was observed in case the application of fungicide Baytan Universal 19,5 WS at the concentration of 0.1% and a considerable growth inhibition was stated at the temperatures of 10°C and 30°C. The effect of seed dressing with the above mentioned preparations on plant infestation by Rhizoctonia fungi was tested in a greenhouse experiment on two cultivars of spring wheat: Banti and Ismena. Baytan Universal 19,5 WS reduced plant infestation especially at the highest soil moisture content of 20 kPa. Biopreparation Biochikol 020 PC and diversification of soil moisture levels did not result in a reduction of wheat infestation rate. This biopreparation stimulated the increase of root mass of both cultivars at moisture content of 20 kPa.
The experiment was conducted in the years 2001–2003 at the Experimental Station in Złotniki. The aim of the performed investigations was to evaluate economic effectiveness of different fungicidal protection programs in winter wheat. Winter wheat of cv. Sakwa was cultivated using the following two variants of seed treatment: 1) Raxil 060 FS at the dose of 60 ml/100 kg grain, 2) Raxil 060 FS + Latitude 125 FS at the doses of 60 and 200 ml/100 kg, and five variants of fungicidal foliar protection: 1) Vista 228 SE, 2) Sportak Alpha 380 EC, 3) Sportak Alpha 380 EC + Vista 228 SE, 4) Sportak Alpha 380 EC + Vista 228 SE + Juwel 250 SC, 5) control – without protection. The use of the above plant protection products contributed to the increase of winter wheat grain yield from 0.60 t/ha to 2.07 t/ha. This increase of yield covered costs of performed chemical control. The economic analysis showed that most effective variant of winter wheat chemical protection was seed treatment with Latitude 125 FS with additional two foliar treatments with the following fungicides: Sportak Alpha 380 EC and Vista 228 SE. Irrespective of the applied seed dressing, additional application of Juwel 250 SC at the stage of early milk maturity turned out to be economically not justified.
The incidence of winter wheat stem base diseases: Fusarium foot rot (Fusarium spp.), eyespot (Ramulispora herpotrichoides), sharp eyespot (Rhizoctonia spp.) and take-all (Gaeumannomyces graminis) in the years 1999–2003 was assessed in this study. Previous crops were barley and oilseed rape. Eyespot occurred on the greatest percentage of plants throughout the whole period of the study. In 2000–2003 a deficiency of rainfall was observed, especially at the time of increased water requirements of plants.