Wheat Culture Research Articles

Intraspecies Interaction of Fusarium graminearum Contributes to Reduced Toxin Production and Virulence.

Fusarium graminearum is a pathogenic fungus that causes Fusarium head blight in wheat and lowers the yield and quality of grains by contamination with the trichothecene mycotoxin deoxynivalenol. The fungi coexist and interact with several different fusaria as well as other plant pathogenic fungi and bacteria in the field. In Canada, F. graminearum exists as two main trichothecene chemotypes: 3-acetyldeoxynivalenol and 15-acetyldeoxynivalenol. To understand the potential interactions between two isolates of these chemotypes, we conducted coinoculation studies both in culture and in planta. The studies showed that intraspecies interaction reduces trichothecene yield in culture and disease symptoms in wheat. To elucidate the genes involved in the intraspecies interaction, expression profiling was performed on RNA samples isolated from coinoculated cultures, and potential genes were identified by using the genome sequences of the respective isolates.

IN VITRO GROWTH RATE OF Kappaphycus alvarezii MICROPROPAGULE AND EMBRYO BY ENRICHMENT MEDIUM WITH SEAWEED EXTRACT

The development of micropropagule and embryo of seaweed depend on nutrient and fertilizer used. Seaweed has been reported contain hormone regulators such as auxine, cytokinine, gibbereline, and various minerals applied in stimulating the growth ocra plant and wheat culture. The objectives of this study were to determine the potential of Kappaphycus alvarezii extract and its optimal concentration in accelerating of Kappaphycus alvarezii micropropagule and embryo growth. Micropropagule and embryo produced through callus induction were planted into PES 1/20 liquid medium supplemented with seaweed extract at the concentrations of 0 (control), 25, 50, 75, and 100 μL in 10 mL of medium. The results showed that medium enrichment with 50 μL of seaweed extract had the highest survival rate and growth of thallus. In addition, this concentration was also resulted in a good performance of K. alvarezii thallus with the lighter color. The advantage of this study for seaweed cultivation in Indonesia, among others, seaweed can be used as fertilizer, especially in the maintenance of seaweed seed, so that cultivation can be better develop.

A new preparative method for simultaneous purification of ochratoxin A and ochratoxin B from wheat culture inoculated withAspergillus ochraceus

Ochratoxins are a mycotoxin family frequently found in agricultural commodities worldwide and pose a potential health risk to humans and animals. To obtain large amounts of high-purity ochratoxins for food safety monitoring and toxicological research, a novel and effective method was established for simultaneous purification of ochratoxin A (OTA) and ochratoxin B (OTB) from a wheat culture inoculated with an ochratoxin-producing Aspergillus strain. The inoculated wheat culture was first extracted with methanol:water (80:20, v/v), followed by one or two cleanup procedures involving acid-assisted liquid-liquid extraction and gel permeation chromatography. Subsequently, target analytes were separated and collected using preparative high performance liquid chromatography. Finally, a combined approach of ultra-high performance liquid chromatography, ultraviolet spectrophotometry and mass spectrometry was applied for purity analysis and structural identification of the obtained toxins. As a result, 100 g of an inoculated wheat culture yielded 69 mg of OTA and 6 mg of OTB with purities greater than 98%. This proposed method might serve as a valuable reference to obtain expensive ochratoxin standards. To the best of our knowledge, this is the first report on simultaneous preparation of OTA and OTB from artificially inoculated wheat culture.

Metabolism of 14C-labeled polychlorinated biphenyl congeners by wheat cell suspension cultures

The metabolism of [UL-14C]-2,2′,5,5′-tetrachlorobiphenyl (14C-PCB-52), [UL-14C]-2,2′,4,4′,5,5′-hexachlorobiphenyl (14C-PCB-153, and a congeneric mixture of [UL-14C]-labeled polychlorinated biphenyls (14C-PCB-Mix) was studied in cell suspension cultures of wheat (Triticum aestivum L. cv. ‘Heines Koga II’). About 50% of applied 14C-PCB-52 (20 μg/assay) was transformed during 96 h of incubation. While 7.6% on non-extractable residues emerged, turnover of 14C-PCB-52 was mainly due to soluble polar metabolites. These were subjected to chemical glycoside cleavage. In the resulting hydrolysate, four aglycons were identified by GC-EIMS, namely four tetrachloro-hydroxy-biphenyl isomers (C6H6Cl4O, M+· at m/z = 306, 308, 310 and 312), and one trichloro-hydroxy-biphenyl (C6H7Cl3O, M+· at m/z = 272, 274 and 276). Number and character of hydroxylated products pointed to cytochromes P450 as enzymatic catalysts of hydroxylation. 14C-PCB-153 was metabolized by wheat to minor degree if at all. Due to GC-EIMS analysis, of 14C-PCB-Mix consisted of biphenyl, one mono-, four di-, seven tri-, eleven tetra-, and four pentachlorobiphenyls besides traces of further mono- and hexachlorobiphenyls. Among these were PCB-28, PCB-52, PCB 101, and PCB-118 (identified by seven key congeners standard). The mixture resembled industrial products Clophen A30 or Aroclor 1016. Metabolic turnover of applied 14C-PCB-Mix (15 μg/assay) was 30% after 96 h; 8.4% of non-extractable residues emerged. Using DDE (p,p’-dichlorodiphenyl-dichloroethylene) as internal standard it was demonstrated that biphenyl, one monochloro-, two dichloro-, and one trichlorobiphenyl were completely metabolized to polar products. Partial metabolization occurred with one di-, five tri-, and four tetrachlorobiphenyls. Two tri-, four tetra-, and all pentachlorbiphenyls proved to be stable. Due to strong interference by matrix, evaluation of three congeners was not possible. In addition to wheat, results of similar experiments with cell cultures of other species are briefly mentioned.

Multi-temporal Multi-spectral and Radar Remote Sensing for Agricultural Monitoring in the Braila Plain

The objective of the paper is to investigate the sensitivity of Landsat OLI and C-band radar signals to monitor an agricultural area affected by soil salinization and land degradation. The chosen test area - Braila Plain has the special particularities such as: dry climate, high annual average temperatures (9-110C), very dry and hot summers which cause a large potential evapotranspiration and conduct to a moisture deficit in soil, alkaline soils, winter winds with an average speed of 2.7 - 3.4 m/s. The soil type and climate conditions favor the culture of maize (50%), wheat and successive crops (16%), alpha-alpha (18%), sugar beet (6%), sunflower (7%), vegetables and other crops (3%). Taking into account the soil type, climate conditions and geomorphological characteristics of the studied area, the paper focuses on evaluation of Sentinel-1 sensor capabilities to monitor soil degradation and surface soil moisture. A multi-temporal series of Sentinel-1 data gathered from October 2014 until January 2015 is used. Crop growing stages are investigated with multi-temporal Landsat OLI and MODIS data. The normalized difference vegetation index (NDVI), specific leaf area index, land thermal index, soil moisture index and soil salinity information are retrieved from Landsat data. The potential evapotranspiration is computed from MODIS data to evaluate the effects of soil salinity on growing crops. The results confirm soil degradation and the synergy of using multi-spectral and radar data for crops monitoring.

Дослідження андрогенезу in vitro в культурі пиляків сортів та реципрокних гібридів пшениці м’якої озимої

Testing of haploprodution ability in vitro anther culture of bread winter wheat was studied. The different nature of indicator inheritance of forming of tumors and regeneration of green plants for F1 hybrids were detected: effects of heterosis and depression, intermediate nature, and the inheritance of signs at the level of the parents. The 283 green plant-regenerants were obtained by anther culture of winter wheat.

Estimation of cation exchange capacity and cation saturation of Luvisols developed from loess

The cation exchange capacity and saturation of the sorptive complex with base cations are very important indicators for quality assessment of soils, because they define soil fertility and resistance to chemical degradation. The objective of the following study was to estimate the cation exchange capacity and saturation with exchangeable cations of Luvisols developed from loess, under agricultural use. The study comprised 12 pedons under winter wheat culture, classified into various complexes of soil suitability. Exchangeable cations of alkaline character were assayed with the Pallmann method in 1 mol NH4Cl dm-3 extract with pH 8.2. The content of cations Ca2+, K+ and Na+ was determined with a flame photometer, while that of Mg2+ was measured with the AAS method. In the Ap horizons of the analyzed soils, the quantitative sequence of base cations was most frequently Ca2+>Mg2+>K+>Na+. The total exchange bases (TEB) was favourable in most of the soils (3.8-16.9 cmol(+) kg-1), and the total acidity (TA) was varied (0.53.7 cmol(+) kg-1) but generally low. The cation exchange capacity (CEC) in the Ap, Et, EB, Bt and BC horizons of the soils was assessed as medium or high (5.2-17.9 cmol(+) kg-1). Only the C horizon, containing calcium carbonate, was characterised by very high CEC (76.2 cmol(+) kg-1). The base saturation (BS) was highly favourable in most of the soils (62.9-99.4%) and increased deeper into the pedon. The soils were characterised by generally favourable shares of particular cations: the percentage of Ca2+ was 51.5-95.1%, most often higher than the optimum, while the shares of Mg2+ and K+ were slightly below the optimum. The calculated quantitative ratios between the cations showed very strong variation of values among particular pedons. The content of Mg2+ cations and the values of TEB and CEC in the Ap horizons of soils from the very good wheat complex were lower than in the Ap horizons of soils from the good wheat complex and the deficient wheat complex, whereas the levels of Ca2+, K+, Na+ and H+ as well as BS displayed only minor differences.

The effects of phenoxy herbicide MCPA on non-target vegetation in spring wheat (Triticum aestivum L.) culture

The presentation was made at the 8th international conference “The Vital Nature Sign” on 15–17 May, 2014 The study examined the non-target effects of phenoxy herbicide MCPA (4-chloro-2-methyl-phenoxy acid) on the morphological and physiological characteristics of spring wheat (Triticum aestivum L.) under field conditions. The experiment was conducted in 4 mesocoms plots (0.1 a) from May to August 2012. The plants were sprayed directly with herbicide spray solutions equivalent of recommended field application rate. The mea­sured endpoints were as follows: height of the shoots, length of the roots, dry biomass, concentrations of chlorophyll a, b, caro­tenoids, malondialdehyde (MDA). The yield of wheat and residues of MCPA in wheat tissues and soil were also estimated. It was observed that herbicide slightly reduced spring wheat stem height (by 9%, p 0.05). Dry weight of spring wheat stems and roots decreased by 14% (p 0.05), respectively. The herbicide did not evoke significant effect on the content of photosynthetic pigments and MDA in plant tissues. MCPA herbicide residues were observed only in soil and stems of spring wheat and were 0.97 μg/kg and 0.047 mg/ kg, respectively.

Genetic relationships, carbendazim sensitivity and mycotoxin production of the Fusarium graminearum populations from maize, wheat and rice in eastern China.

Members of the Fusarium graminearum species complex (FGSC) are important pathogens on wheat, maize, barley, and rice in China. Harvested grains are often contaminated by mycotoxins, such as the trichothecene nivalenol (NIV) and deoxynivalenol (DON) and the estrogenic mycotoxin zearalenone (ZEN), which is a big threat to humans and animals. In this study, 97 isolates were collected from maize, wheat, and rice in Jiangsu and Anhui provinces in 2013 and characterized by species- and chemotype-specific PCR. F. graminearum sensu stricto (s. str.) was predominant on maize, while most of the isolates collected from rice and wheat were identified as F. asiaticum. Fusarium isolates from three hosts varied in trichothecene chemotypes. The 3-acetyldeoxynivalenol (3ADON) chemotype predominated on wheat and rice population, while 15ADON was prevailing in the remaining isolates. Sequence analysis of the translation elongation factor 1α and trichodiene synthase indicated the accuracy of the above conclusion. Additionally, phylogenetic analysis suggested four groups with strong correlation with species, chemotype, and host. These isolates were also evaluated for their sensitivity to carbendazim and mycotoxins production. The maize population was less sensitive than the other two. The DON levels were similar in three populations, while those isolates on maize produced more ZEN. More DON was produced in carbendazim resistant strains than sensitive ones, but it seemed that carbendazim resistance had no effect on ZEN production in wheat culture.

Amplitude térmica para germinação de conídios de Drechslera tritici-repentis

A mancha-amarela do trigo, causada pelo fungo Drechslera tritici-repentis, é de ocorrência mundial e uma das principais doenças da cultura. No Brasil, a mesma está presente em todas as safras e pode reduzir o rendimento de grãos em mais de 40%. A sua ampla adaptabilidade a ambientes diversos pode estar relacionada à capacidade dos esporos germinarem sob diferentes temperaturas, assunto que foi examinado neste experimento conduzido na UPF, em 2011. Suspensões de conídios (350 µL) foram depositadas em placas de Petri com meio ágar-água e incubadas em câmara tipo BOD, na presença e ausência de luz, a -5, 0, 5, 10, 15, 20, 25, 30, 35 e 40ºC, por 2, 4, 6, 8 e 10 horas. O trabalho foi conduzido duas vezes, em delineamento inteiramente casualizado, com quatro repetições. Os conídios germinaram tanto na presença como na ausência de luz. A germinação foi nula a -5ºC ou 40ºC. A mesma foi detectada após 2h e aumentou com o tempo de incubação. Através de polinômios de segundo grau estimou-se a máxima germinação a 19ºC e 9,5h de incubação. Houve predominância da germinação bipolar (frequência de 45,0%), seguida da intercalar (33,5%) e da unipolar (21,5%). Os resultados obtidos indicam grande amplitude térmica para germinação dos conídios de D. tritici-repentis, o que explica, parcialmente, sua ampla distribuição geográfica.

Morpho-histology and genotype dependence of in vitro morphogenesis in mature embryo cultures of wheat

Cellular totipotency is one of the basic principles of plant biotechnology. Currently, the success of the procedure used to produce transgenic plants is directly proportional to the successful insertion of foreign DNA into the genome of suitable target tissue/cells that are able to regenerate plants. The mature embryo (ME) is increasingly recognized as a valuable explant for developing regenerable cell lines in wheat biotechnology. We have previously developed a regeneration procedure based on fragmented ME in vitro culture. Before we can use this regeneration system as a model for molecular studies of the morphogenic pathway induced in vitro and investigate the functional links between regenerative capacity and transformation receptiveness, some questions need to be answered. Plant regeneration from cultured tissues is genetically controlled. Factors such as age/degree of differentiation and physiological conditions affect the response of explants to culture conditions. Plant regeneration in culture can be achieved through embryogenesis or organogenesis. In this paper, the suitability of ME tissues for tissue culture and the chronological series of morphological data observed at the macroscopic level are documented. Genetic variability at each step of the regeneration process was evaluated through a varietal comparison of several elite wheat cultivars. A detailed histological analysis of the chronological sequence of morphological events during ontogeny was conducted. Compared with cultures of immature zygotic embryos, we found that the embryogenic pathway occurs slightly earlier and is of a different origin in our model. Cytological, physiological, and some biochemical aspects of somatic embryo formation in wheat ME culture are discussed.

Wheat Culture Water Needs Diagnosis Carried Out in the Sidi Bel Abbes Semi Arid Valley

The Useful Agricultural Area Management Mode in the region of Sidi Bel Abbes reveals prima facie an underutilization of the region’s agricultural potential cause of low rainfall level and particularly random distribution often results in a situation of cruel water stress throughout the phenological stages of cereals. Some daily, monthly and decadal climate parameters, as rainfalls, Potential Evapotranspiration, Maximal Evapotranspiration and temperature and their evolution studies, related to the different stages of development of this culture, helps to identify the phases during which water consumption is really urging. Knowledge of this plant high water demand allows us to target the best moment to palliate those needs to enhance the final productivity of this crop in the plain of Sidi Bel Abbes northwestern Algeria at the Mediterranean Sea. Works during the 2007 2011 campaign on “Waha” durum variety Original Research Article American Journal of Experimental Agriculture, 4(4): 457-468, 2014 458 showed that the wheat water needs are bound to variations in the intensity of the climatic demand. This one, taken over from planting to heading stage reached an amount of 396 mm while durum wheat evoluting in terms of maximum irrigation consumes an equivalent of 351.5 mm average of water. This sentence implies the importance of the water problem facing the cereal, especially those of short cycle in the semi arid areas. Durum wheat consumes an average 74% of its needs, worth of 268.60 mm of water over a period from the third decade of March to the first half of May when the rainfall recorded during the same period with an average of 34.46 mm, covers only 13% of total crops water requirements. The large amount of this deficit clearly accused justifies the very pronounced low grain yields recorded in the region. Hence, the productivity of this crop depends crucially on the choice of a tolerant genotype to semi arid conditions on one hand and the use of supplemental irrigation on the other hand taking into account the requirements of the culture. Wheat crop coefficients determined for the region permit an efficient irrigation application.

Adaptive value of ryegrass biotypes with low-level resistance and susceptible to the herbicide fluazifop and competitive ability with the wheat culture

Ryegrass is the main weed in wheat crop, causing yield loss due to competition by environmental resources. The objectives of this study were to estimate the fitness cost of ryegrass biotypes with low-level resistance and susceptible to fluazifop and to investigate the relative competitive ability of these biotypes between themselves and against the crop. Thus, fitness cost and competitive ability experiments were conducted under greenhouse conditions. For the fitness cost experiments, the low-level resistant ryegrass biotypes and those susceptible to fluazifop were used. For competitive ability, the treatments were arranged in a replacement series, with five proportions of the wheat cultivar FUNDACEP Horizonte and the low-level resistant and susceptible ryegrass biotypes 100:0, 75:25, 50:50, 25:75 and 0:100. Competitive analysis was carried out through diagrams applied to the replacement experiments and use of relative competitiveness indices. Variables evaluated were plant height, in the fitness cost experiment, and leaf area and shoot dry biomass in both experiments. The ryegrass biotypes show overall similar fitness cost and competitive ability. The wheat cultivar FUNDACEP Horizonte is superior in competitive ability to the ryegrass biotype with low-level resistance and equivalent to the susceptible biotype.

RNA-guided genome editing for target gene mutations in wheat.

The clustered, regularly interspaced, short palindromic repeats (CRISPR) and CRISPR-associated protein (Cas) system has been used as an efficient tool for genome editing. We report the application of CRISPR-Cas–mediated genome editing to wheat (Triticum aestivum), the most important food crop plant with a very large and complex genome. The mutations were targeted in the inositol oxygenase (inox) and phytoene desaturase (pds) genes using cell suspension culture of wheat and in the pds gene in leaves of Nicotiana benthamiana. The expression of chimeric guide RNAs (cgRNA) targeting single and multiple sites resulted in indel mutations in all the tested samples. The expression of Cas9 or sgRNA alone did not cause any mutation. The expression of duplex cgRNA with Cas9 targeting two sites in the same gene resulted in deletion of DNA fragment between the targeted sequences. Multiplexing the cgRNA could target two genes at one time. Target specificity analysis of cgRNA showed that mismatches at the 3′ end of the target site abolished the cleavage activity completely. The mismatches at the 5′ end reduced cleavage, suggesting that the off target effects can be abolished in vivo by selecting target sites with unique sequences at 3′ end. This approach provides a powerful method for genome engineering in plants.

Mycotoxin profile of Fusarium langsethiae isolated from wheat in Italy: production of type‐A trichothecenes and relevant glucosyl derivatives

Fusarium langsethiae, formally described as a new species over a decade ago, has been identified as the main producer of HT-2 (HT2) and T-2 (T2) toxins in Europe in small cereal grains. Mycotoxin contamination caused by this Fusarium species can represent a food safety hazard that deserves further attention. In the present work, the mycotoxin profile in wheat cultures of F. langsethiae is presented with particular reference to the production of major type-A trichothecenes and their glucosyl derivatives. F. langsethiae isolates, representative of the major Italian wheat cultivation areas, were tested for the production of T2, HT2, diacetoxyscirpenol (DAS) and neosolaniol (NEO), and relevant glucosyl derivatives. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used for the identification and chemical characterization of these metabolites. F. langsethiae isolates under investigation resulted to be potent producers of T2, HT2 and NEO. Furthermore, a well-defined set of isolates, all originating from Central Italy, produced also DAS. All isolates were found to be able to produce HT2 glucosyl derivatives, whereas only traces of T2 glucoside were detected in one sample. Furthermore, two mono-glucosyl derivatives of NEO and one mono-glucoside derivative of DAS were identified and characterized. The screening for the presence/absence of glucosylated trichothecenes in analyzed fungal extracts revealed a general co-occurrence of these derivatives with the parent toxin at levels that could be roughly estimated to account up to 37% of the relevant unconjugated toxin. This is the first report of the production of glucosylated trichothecenes by F. langsethiae cultured on small grains.

The Influence of Fusarium Infections on the Quality Parameters and Production of Four Wheat Varietes, in Different Infection Conditions

Abstract. Wheat is one of the oldest cultivated plants and most important food plant, the wheat flour bread is the basic food for majority of world population. At the same time the corn crop is affected by many diseases that cause quantitative and qualitative losses. From the many diseases common to the wheat culture, fusarium head blight, produced by species of the Fusarium genus, is appreciated in most parts of the world, as one of the most damaging disease. In addition to losses of production, 10-2 percent in favourable conditions, the flour for bread that came from crops affected by Fusarium is inferior in terms of quality, the bread has low volume and low protein content. The studies conducted have shown the impact of Fusarium infection on dough properties and additional properties for baking therefore a decrease in flour yield and also an increase in ash content in the flour obtained from grain infected with Fusarium observing also a darker colour and an unpleasant odor of flour, protein content and wet gluten increase or decrease after Fusarium infection. Determination of quality parameters, protein, ash and gluten and the production of four wheat varieties in different testing conditions. Study of the Fusarium infection effect on quality parameters and yield was achieved through experiences located in three repetitions. There have been tested four different variants uninoculated - untreated, inoculated - treated, inoculated - untreated, uninoculated - treated on four varieties of wheat Ariesan, Andrada, Apulum and Dumbrava. The artificial infections with Fusarium spp. were made by spraying method according to Ceapoiu and Floare Negulescu, ( 1988 ) and the treatments applied on vegetation were done with fungicides Nativo and Prosaro 460 EC. The testing modality influenced the behaviour of the varieties in terms of production and quality parameters obtained. For all varieties studied, in the variants were applied, vegetation treatment, even though artificial inoculation that have been made high productions were obtained.

Research Concerning the Tehnology of Autumn Wheat Culture within Ecological and Bio-dynamic Systems

The goal of organic and biodynamic production methods is to create and maintain a balance between the environment protection and the growing technology for each crop tipe, beginning with the soil tillage system wich is aimed to ensure harmony and keeps a balance between the natural resources and the crop needs. The yields level depends mostly on the optimum application of all the technological sequences beginning with the soil selection and finishing with the crop harvesting. The agricultural product obtained has to be satisfactory both in quantity and quality. Nowadays, although the quantity is very important, more often the stress lays on quality; consumers being more and more oriented towards healthy food which has a great contribution to the living standard enhancement.

Parameter identification of the STICS crop model, using an accelerated formal MCMC approach

This study presents a Bayesian approach for the parameters' identification of the STICS crop model based on the recently developed Differential Evolution Adaptive Metropolis (DREAM) algorithm. The posterior distributions of nine specific crop parameters of the STICS model were sampled with the aim to improve the growth simulations of a winter wheat (Triticum aestivum L.) culture. The results obtained with the DREAM algorithm were initially compared to those obtained with a Nelder-Mead Simplex algorithm embedded within the OptimiSTICS package. Then, three types of likelihood functions implemented within the DREAM algorithm were compared, namely the standard least square, the weighted least square, and a transformed likelihood function that makes explicit use of the coefficient of variation (CV). The results showed that the proposed CV likelihood function allowed taking into account both noise on measurements and heteroscedasticity which are regularly encountered in crop modelling.

Winter wheat cells subjected to freezing temperature undergo death process with features of programmed cell death

Programmed cell death is a process defined as genetically regulated self-destruction or cell suicide. It can be activated by different internal and external factors, but few studies have investigated whether this process occurs under cold and freezing temperatures. In this study, a freezing treatment (-8°C for 6h) induced cell death with features of programmed cell death in suspension cultures of winter wheat (Triticum aestivum L.). This process occurred for 10days after cold exposure. The death of cells in culture was slow and prolonged, and was accompanied by protoplast shrinkage, DNA fragmentation, and an increase in the level of reactive oxygen species. Other changes observed after the freezing treatment included an increase in the respiration rate, changes in mitochondrial transmembrane potential (∆Ψ m ), and the release of cytochrome c from mitochondria into the cytosol. These findings indicated that mitochondria are involved in the cell death process that occurs after a freezing treatment in cells of winter wheat.

Regeneration of plantlets from unpollinated ovary cultures of Ethiopian wheat (Triticum turgidum and Triticum aestivum)

An in vitro culture protocol was established for direct regeneration of plantlets from unpollinated ovary cultures of four Ethiopian wheat varieties. Unpollinated ovaries were excised from durum wheat (Yerer and Ude varieties) and bread wheat (Simba and Galama varieties). Analysis of variance (ANOVA) has shown that genotypes, types of media, concentrations of 2,4-dichlorophenoxy acetic acid (2,4-D) and kinetin (KIN) and durations of cold pretreatment at 4°C significantly (P≤0.05) affected direct formation of embryonic tissues independently. Stage II of wheat spikes, MS medium containing 1 mg/l of each of 2,4-D and KIN and 15 days of cold pretreatment were found to be the best conditions for direct formation of embryonic tissues. The highest frequency of shoots were regenerated from the cultured embryonic tissues of Yerer (41.6% ) and Simba (41.3%) on medium containing 0.1 mg/l 2,4-D. From a total of 14,524 cultured unpollinated ovaries, 1,100 embryonic tissues (7.6 %) and 75 regenerants were obtained. The average percentage of embryonic tissues and regenerants were 9.0 and 1.1% from 3,444; 9.8 and 0.55% from 4,732; 5.6 and 0.17% from 2,988; 4.7 and 0.12% from 3,360 cultured unpollinated ovaries for varieties Yerer, Simba, Ude and Galama, respectively. Keywords: Embryonic tissues, Unpollinated ovaries , regenerants, wheat varieties African Journal of Biotechnology Vol. 12(39), pp. 5754-5760