Amaranth Species Research Articles

First Report of Pythium myriotylum Causing Damping-Off of Amaranthus tricolor in Florida

Amaranthus tricolor ‘Garnet Red’ is an edible ornamental often sold for its striking color as well as its culinary uses. There are several cultivated species of amaranth that vary in shape, size, and color. This particular cultivar (Garnet Red) is praised for its high nutritional value. It can be harvested at any age, making it commonly used as either microgreens, sprouts, salad leaves, or for seed and grain. Amaranth is easy to grow and reasonable yields can be produced even in poor soils (Sealy et al. 1990), but damping-off of seedlings by Pythium sp. is a problem for producers and breeders (National Research Council 1984). In November 2011, amaranth seedlings cv. Garnet Red from a local nursery were submitted to the Florida Extension Plant Diagnostic Clinic in Homestead, FL. Symptoms began as a rot and that ultimately resulted in the loss of the entire planting of seedlings, causing post-emergent damping-off in both the greenhouse and shadehouse locations where the crop was grown. A Pythium sp. was confirmed via microscopic observations from cultures on PARP medium showing aplerotic oospores, about 20 to 27 μm in diameter and walls up to 2 μm thick (n = 15) (van der Plaats-Niterink 1981). The region of rDNA, the internal transcribed spacer (ITS), was amplified with primers ITS1 and ITS4 and the PCR product was sequenced. The resulting sequence was deposited in GenBank (accession no. KF008434). A 99% nucleotide identity was found with a BLAST search in GenBank with an isolate of P. myriotylum (HQ237488) associated with bud rot of oil palm. MEGA 6.06 software was used for the phylogenetic analysis by the maximum likelihood method (Tamura-Nei model). Our isolate grouped with other P. myriotylum isolates with high support (100% bootstrap values, 1,000 replicates). To confirm pathogenicity, amaranth ‘Garnet Red’ seeds were sown in 4-inch pots with Promix BX Mycorrhizae dry mix under greenhouse conditions where temperature ranged from 25 to 32°C. Seeds were inoculated 24 h after sowing by drenching with a 5 ml sporangial suspension (1 × 10⁶ sporangia/ml) of our P. myriotylum isolate. Control plants were drenched with an equal volume of sterile water. Five plants per treatment were used and the experiment was repeated. After 72 h, seedlings had collapsed. P. myriotylum was reisolated from symptomatic tissues and was confirmed through morphological and molecular analyses. No symptoms developed on the control plants. P. myriotylum is an aggressive pathogen causing important economic losses with a very large host distribution worldwide in warm regions. In south Florida, it had previously been reported causing aerial blight of tomato, and more recently, basal rot on Echeveria (Roberts et al. 1999; Suarez et al. 2016). To our knowledge, this is the first report of P. myriotylum causing damping-off of an Amaranthus species in Florida.

Phytochemical Content and Antioxidant Activity of Five Grain Amaranth Species

Investigation into the antioxidant properties of plants is a very active field of research. Amaranths are underutilized pseudo-cereals with nutraceutical potentials. The phytochemical and antioxidant activity of five grain amaranth species were evaluated using standard procedures. Highest tannin content (0.14 g/100g) and Fe chelating (66.72%) capacity was recorded in Amaranthus caudatus. Amaranthus cruentus had the highest total flavonoid (9.93 mg CE/100g) content. Amaranthus Hybridus had the highest Phytate (1.58 g/100g), total polyphenol (30.79 mg GAE/100g), DPPH scavenging activity (93.35 %), ferric reducing power (0.19 g/100g), total antioxidant 199.93 mg AAE/100g) and ABTS (201.54 mmol TE/100g) content respectively. Strong correlation was observed between the phytochemicals and antioxidant tested. From the results, grain amaranth species possess antioxidant capacity and polyphenolic content. These qualities in amaranths have promising potential means of food biofortifications.

Natural diversity of hydroxycinnamic acid derivatives, flavonoid glycosides, carotenoids and chlorophylls in leaves of six different amaranth species

Amaranth species are globally grown food crops. However, knowledge about the composition of their secondary metabolites is insufficient. Here, selected hydroxycinnamic acid derivatives, flavonoid glycosides, carotenoids and chlorophylls in the leaves of 14 genotypes from six different amaranth species were identified and quantified. For the first time, caffeic acid esters of isocitric and several aldaric acids were isolated and quantified in a leafy food matrix. High concentrations of hydroxycinnamic acid derivatives and chlorophylls, and moderate amounts of flavonoids and carotenoids were detected. A hierarchical clustering method of the metabolic profiles followed by Random Amplification of Polymorphic DNA (RAPD)-PCR fingerprinting was used to group the genotypes. Using this combined approach, three main groups of amaranth species were assigned. The information provided in this study increases the attractiveness of the amaranth genus as a food crop due to its strong diversity of plant secondary metabolites that are associated with numerous health-promoting benefits.

The Accumulation of Phenolic Compounds in Genetically Selected Amaranthus hybridus is Influenced by Endophytic Natural Growth Regulator

Amaranth ( Amaranthus spp . L.) ( Amaranthaceae ), an endemic plant in Central and South America, grows worldwide, being cultivated in many temperate and tropical countries. Although several species of amaranth are frequently considered weeds, the plant is recognized as a food, constructive medicine, a source of protein and minerals livestock feed. The plant is widely cultivated, promoted, and increasingly consumed as a leafy vegetable and traditional medicine in Africa. Despite progressive genetic improvement and modern plant growing technologies, unfavorable climatic and ecological factors reduce the yield, and quality of the active plant botanicals. The role of bio-transformed endophytic microbial plant growth regulator formulation (BESF) on yield and accumulation of phenolic compounds in amaranth leaves is poorly understood. The current study assessed the effects of pre-sowing seed treatments with 0.0 %, 0.2 % and 0.4 % concentrations of BESF solution on germination, leaf yield, flavor and phenolic content in genetically selected Amaranthus hybridus var . cruentus . Data collected were subjected to analysis of variance (ANOVA). Significant treatment means were separated using Tukey test at p < 0.05. BESF significantly increased fresh marketable leaf yield by over 360 kg/ha (29 %) compared to the control. The total flavonoid content in the leaves was raised by 34 % and 47 % with 0.2 % and 0.4 % BESF solution treatments respectively, compared to control. Maximum concentration levels of rutin, apigenin, apigetrin, and quercetin was obtained with 0.4% BESF solution treatment. An analysis of the collected data suggest that BESF was effective in overall improvement in leaf yield, chemical content, and flavor of A. hybridus var . cruentus, allowing us to recommend BESF application to raise A. hybridus var . cruentus leaves for nutrition and pharmacological applications.

Agronomic, Chemical, and Antioxidant Characterization of Grain Amaranths Grown in a Mediterranean Environment

The use of amaranth (Amaranthus spp.) in the food and dietary supplements industry is increasing. The aim of this work is to promote the Mediterranean area as a production hot spot, by using multivariate statistical analyses on data obtained in two‐year trials and relating to morphological, productive, and qualitative traits and antioxidant activity of 20 accessions of five amaranth species (A. caudatus L., A. cruentus L., A. hybridus L., A. hypochondriacus × hybridus L., A. hypochondriacus L.). Amaranthus cruentus accessions (Mexicane and New Mexico) were stable and highly productive (&gt;2.7 t seeds ha−1), while Kinnaury Dhankar accession showed the highest protein percentage (17%). Amaranthus hypochondriacus (Orange Giant and Burgundy) possessed the highest oil percentage (always above 5.7%). A high amount in linoleic, cis‐oleic, and palmitic acids, and an interesting saturated/unsaturated acids ratio ranging from 0.26 (A. hybridus) to 0.32 (A. hypochondriacus) were detected. The unsaponifiable fraction revealed the abundance of squalene in all species, while total tocopherol concentrations were lower than expected.

Chlorogenic acid versus amaranth's caffeoylisocitric acid – Gut microbial degradation of caffeic acid derivatives

The almost forgotten crop amaranth has gained renewed interest in recent years due to its immense nutritive potential. Health beneficial effects of certain plants are often attributed to secondary plant metabolites such as phenolic compounds. As these compounds undergo significant metabolism after consumption and are in most cases not absorbed very well, it is important to gain knowledge about absorption, biotransformation, and further metabolism in the human body.Whilst being hardly found in other edible plants, caffeoylisocitric acid represents the most abundant low molecular weight phenolic compound in many leafy amaranth species. Given that this may be a potentially bioactive compound, gastrointestinal microbial degradation of this substance was investigated in the present study by performing in vitro fermentation tests using three different fecal samples as inocula. The (phenolic) metabolites were analyzed using high-performance liquid chromatography/electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS). Furthermore, quantitative polymerase chain reaction (qPCR) analyses were carried out to study the influence on the microbiome and its composition. The in vitro fermentations led to different metabolite profiles depending on the specific donor. For example, the metabolite 3-(4-hydroxyphenyl)propionic acid was observed in one fermentation as the main metabolite, whereas 3-(3-hydroxyphenyl)propionic acid was identified in the other fermentations as important. A significant change in selected microorganisms of the gut microbiota however was not detected.In conclusion, caffeoylisocitric acid from amaranth, which is a source of several esterified phenolic acids in addition to chlorogenic acid, can be metabolized by the human gut microbiota, but the metabolites produced vary between individuals.

Seed germination in relation to the invasiveness in spiny amaranth and edible amaranth in Xishuangbanna, SW China.

Both spiny and edible amaranths (Amaranthus spinosus and A. tricolor) are exotic annuals in China that produce numerous small seeds every year. Spiny amaranth has become a successful invader and a troublesome weed in Xishuangbanna, but edible amaranth has not, although it is widely grown as a vegetable there. As seed germination is one of the most important life-stages contributing to the ability of a plant to become invasive, we conducted experiments to compare the effects of high temperature and water stress on seed germination in two varieties each of spiny amaranth and edible amaranth. Overall, the seeds of both amaranth species exhibited adaptation to high temperature and water stress, including tolerance to ground temperatures of 70°C for air-dried seeds, which is consistent with their behavior in their native ranges in the tropics. As expected, the invasive spiny amaranth seeds exhibited higher tolerance to both continuous and daily periodic high-temperature treatment at 45°C, and to imbibition-desiccation treatment, compared to edible amaranth seeds. Unexpectedly, edible amaranth seeds exhibited higher germination at extreme temperatures (10°C, 15°C, and 40°C), and at lower water potential (below -0.6 MPa). It is likely that cultivation of edible amaranth has selected seed traits that include rapid germination and germination under stressful conditions, either of which, under natural conditions, may result in the death of most germinating edible amaranth seeds and prevent them from becoming invasive weeds in Xishuangbanna. This study suggests that rapid germination and high germination under stress conditions—excellent seed traits for crops and for many invasive species—might be a disadvantage under natural conditions if these traits are asynchronous with natural local conditions that support successful germination.

Insights on Structure and Function of a Late Embryogenesis Abundant Protein from Amaranthus cruentus: An Intrinsically Disordered Protein Involved in Protection against Desiccation, Oxidant Conditions, and Osmotic Stress.

Late embryogenesis abundant (LEA) proteins are part of a large protein family that protect other proteins from aggregation due to desiccation or osmotic stresses. Recently, the Amaranthus cruentus seed proteome was characterized by 2D-PAGE and one highly accumulated protein spot was identified as a LEA protein and was named AcLEA. In this work, AcLEA cDNA was cloned into an expression vector and the recombinant protein was purified and characterized. AcLEA encodes a 172 amino acid polypeptide with a predicted molecular mass of 18.34 kDa and estimated pI of 8.58. Phylogenetic analysis revealed that AcLEA is evolutionarily close to the LEA3 group. Structural characteristics were revealed by nuclear magnetic resonance and circular dichroism methods. We have shown that recombinant AcLEA is an intrinsically disordered protein in solution even at high salinity and osmotic pressures, but it has a strong tendency to take a secondary structure, mainly folded as α-helix, when an inductive additive is present. Recombinant AcLEA function was evaluated using Escherichia coli as in vivo model showing the important protection role against desiccation, oxidant conditions, and osmotic stress. AcLEA recombinant protein was localized in cytoplasm of Nicotiana benthamiana protoplasts and orthologs were detected in seeds of wild and domesticated amaranth species. Interestingly AcLEA was detected in leaves, stems, and roots but only in plants subjected to salt stress. This fact could indicate the important role of AcLEA protection during plant stress in all amaranth species studied.

Effects of different nitrogen forms on growth, phenolics, flavonoids and antioxidant activity in amaranth species

Effects of different nitrogen forms on growth, phenolics, flavonoids and antioxidant activity in amaranth species

Nutritional evaluation of Five Species of Grain Amaranth – An Underutilized Crop

Nutritional evaluation of Five Species of Grain Amaranth – An Underutilized Crop

Germination Response of Four Alien Congeneric Amaranthus Species to Environmental Factors.

Seed germination is the key step for successful establishment, growth and further expansion of population especially for alien plants with annual life cycle. Traits like better adaptability and germination response were thought to be associated with plant invasion. However, there are not enough empirical studies correlating adaptation to environmental factors with germination response of alien invasive plants. In this study, we conducted congeneric comparisons of germination response to different environmental factors such as light, pH, NaCl, osmotic and soil burials among four alien amaranths that differ in invasiveness and have sympatric distribution in Jiangsu Province, China. The data were used to create three-parameter sigmoid and exponential decay models, which were fitted to cumulative germination and emergence curves. The results showed higher maximum Germination (Gmax), shorter time for 50% germination (G50) and the rapid slope (Grate) for Amaranthus blitum (low-invasive) and A. retroflexus (high-invasive) compare to intermediately invasive A. spinosus and A. viridis in all experimental regimes. It indicated that germination potential does not necessarily constitute a trait that can efficiently distinguish highly invasive and low invasive congeners in four Amaranthus species. However, it was showed that the germination performances of four amaranth species were more or less correlated with their worldwide distribution area. Therefore, the germination performance can be used as a reference indicator, but not an absolute trait for invasiveness. Our results also confirmed that superior germination performance in wide environmental conditions supplementing high seed productivity in highly invasive A. retroflexus might be one of the reasons for its prolific growth and wide distribution. These findings lay the foundation to develop more efficient weed management practice like deep burial of seeds by turning over soil and use of tillage agriculture to control these invasive weed species.

Polymorphism of RAPD and ISSR markers in grain amaranth species

Different molecular genetic markers are effectively used in agricultural genetic selection programs. Genetic markers can be used in commercial breeds certification performance, fast and reliable genotype identification, genetic maps creation, genetics, phylogeny and plant systematic studies, which can accelerate selection, provide effective study and culture genofond maintenance. Amaranth, in this regard, has not been studied well, there is not enough data to effectively perform amaranth marker selection or for the certification of new and existing varieties; there are inaccuracies in the systematization of the crop. Important are the questions about the origin of grain amaranth species and the processes of their evolutionary formation. Amaranth is a pseudo-cereal with a millennia-long history, it has been actively cultivated in many countries around the world in recent decades. A high level of alterability and the formation of a huge number of spontaneous hybrids in natural populations of amaranth significantly complicate the identification of individual genotypes and entire taxonomic units of Amaranthus L. Due to the lack of research and depending on the environmental conditions, the morphological markers of amaranth are not able to provide sufficient genomic information to the breeder; thus it is necessary to search for reliable genetic markers that allow the genetic diversity of the Amaranthus L. species to be studied and effectively maintained. This research includes grain amaranth species DNA polymorphism analysis. Using RAPD and ISSR technologies, 203 loci have been identified, of which 173 appear to be polymorphic, 30 monomorphic (found in all genotypes analyzed) and 13 unique (found only in one genotype). Unique and monomorphic DNA loci can be used as specific genetic markers, in particular, for the certification of breeds, which is especially important for the identification of plant material and plant genetic variability monitoring. A high level of DNA polymorphism was revealed (about 85 %), a genetic relationship between grain amaranth species established, their monophyletic origin theory verified. A. mantegazzianus Passer. was proved to be an A. caudatus L. subspecies.

Nutritional evaluation of Five Species of Grain Amaranth – An Underutilized Crop

Variation in the proximate and mineral compositions of twenty nine accessions of grain amaranth (Amaranthus), belonging to five species: Amaranthus caudatus, A. cruentus, A. hybrid, A. hypochondriacus and A. hybridus were evaluated. Results showed that significant (p < 0.05) differences were observed in the proximate and mineral compositions among all the species evaluated. Amaranthus caudatus had the highest levels of crude fibre (4.04 g/100g), sodium (8.95 mg/kg), phosphorus (5765.64 mg/kg), magnesium (2219.15 mg/kg) and aluminum (111.09 mg/kg) contents. Amaranthus cruentus had the highest levels of crude fat (8.68 g/100g), zinc (59.49 mg/kg), copper (6.62 mg/kg), manganese (136.44 mg/kg) and calcium (1642.45 mg/kg). Amaranthus hybridus had the highest levels of protein (17.89 g/100g) and starch (38.01 g/100g). Phosphorus was the most abundant mineral present, followed by potassium and magnesium; while selenium was the least abundant mineral element present. The grain amaranth species have higher protein, crude fibre, starch and essential minerals than commonly consumed cereals and hold promise as a healthy alternative to these cereals and their products.

Leafy amaranthus consumption patterns in Ouagadougou, Burkina Faso

There is a new attention to vegetables as vital components of daily diet. A concerted effort to raise their standing has begun to change mentalities and to fuel a rapid growth of traditional leafy vegetables marketing and consumption in African cities. However, little is known about the production and consumption patterns of these plant foods. This study examined, through a field survey the socio-economic, food consumption and conservation aspects of leafy vegetables in the region of Ouagadougou. It was found that leafy vegetables are cultivated under both rain-fed and irrigated conditions in the villages and also in the city’s gardens. The study has demonstrated that there is considerable indigenous knowledge on the leafy vegetables of the region. Amaranth species are the most cultivated and marketed and have potential for commercialization. They are used for many dishes in the local kitchen. Leafy Amaranths are consumed during all seasons even though they are more available (and cheap) during rainy season (June to end October). Ninety-four per cent of the interviewed people use vegetable Amaranth in sauce. There is a growing trend to use cultivated (introduced) species of Amaranth, which were brought to Africa by colonial powers and gained popularity because they were associated with high status. The introduced species are spreading quickly in a spontaneous manner. This can be a threat to biodiversity. There is need for a conservation initiative for the native species. In the commercialization of leafy vegetable and in particular for Amaranth, women play an important role. That could be optimized for marketing purpose to improve leafy vegetable adding-value. Because transportation is a cost increase factor, and given that cities should be targets for increased consumption, it is necessary to promote peri-urban agriculture of leafy vegetables, by policy guidelines. There is a need of documentation and dissemination of indigenous knowledge on indigenous leafy vegetables. Key words: vegetables, African greens, Amaranthus, micronutrients, biodiversity, horticulture, Ouagadougou, Burkina Faso

Evaluation of Wick-Applied Glyphosate for Palmer Amaranth (Amaranthus palmeri) Control in Sweetpotato

Studies were conducted in 2007 and 2008 at Clinton, NC to determine the effect of glyphosate applied POST via a Dixie wick applicator on Palmer amaranth control and sweetpotato yield and quality. In 2007, treatments consisted of glyphosate wicked sequentially 6 and 8 wk after transplanting (WAP) and glyphosate wicked sequentially 6 and 8 WAP followed by (fb) rotary mowing 9 WAP. In 2008, treatments consisted of glyphosate wicked once 4 or 7 WAP, wicked sequentially 4 and 7 WAP, mowed once 4 WAP, and mowed 4 WAP fb wicking 7 WAP. In 2008, Palmer amaranth control 6 WAP varied by location and averaged 10 and 58% for plots wicked 4 WAP. Palmer amaranth contacted by the wicking apparatus were controlled, but weeds shorter than the wicking height escaped treatment. Palmer amaranth control 9 WAP was greater than 90% for all treatments wicked 7 WAP. Competition prior to and between glyphosate treatments contributed to large sweetpotato yield losses. Treatments consisting of glyphosate 7 or 8 WAP (in 2007 and 2008, respectively) frequently had greater no. 1 and marketable yields compared to the weedy control. However, jumbo, no. 1, and marketable yields for all glyphosate and mowing treatments were generally less than half the hand-weeded check. Cracked sweetpotato roots were observed in glyphosate treatments and percent cracking (by weight) in those plots ranged from 1 to 12% for no. 1 roots, and 1 to 6% for marketable roots. Findings from this research suggest wicking might be useful in a salvage scenario, but only after currently registered preemergence herbicides and between-row cultivation have failed to control Palmer amaranth and other weed species below the sweetpotato canopy.

Crossing Methods and Cultivation Conditions for Rapid Production of Segregating Populations in Three Grain Amaranth Species.

Grain amaranths (Amaranthus spp.) have been cultivated for thousands of years in Central and South America. Their grains are of high nutritional value, but the low yield needs to be increased by selection of superior genotypes from genetically diverse breeding populations. Amaranths are adapted to harsh conditions and can be cultivated on marginal lands although little is known about their physiology. The development of controlled growing conditions and efficient crossing methods is important for research on and improvement of this ancient crop. Grain amaranth was domesticated in the Americas and is highly self-fertilizing with a large inflorescence consisting of thousands of very small flowers. We evaluated three different crossing methods (open pollination, hot water emasculation and hand emasculation) for their efficiency in amaranth and validated them with genetic markers. We identified cultivation conditions that allow an easy control of flowering time by day length manipulation and achieved flowering times of 4 weeks and generation times of 2 months. All three different crossing methods successfully produced hybrid F1 offspring, but with different success rates. Open pollination had the lowest (10%) and hand emasculation the highest success rate (74%). Hot water emasculation showed an intermediate success rate (26%) with a maximum of 94% success. It is simple to perform and suitable for a more large-scale production of hybrids. We further evaluated 11 single nucleotide polymorphism (SNP) markers and found that they were sufficient to validate all crosses of the genotypes used in this study for intra- and interspecific hybridizations. Despite its very small flowers, crosses in amaranth can be carried out efficiently and evaluated with inexpensive SNP markers. Suitable growth conditions strongly reduce the generation time and allow the control of plant height, flowering time, and seed production. In combination, this enables the rapid production of segregating populations which makes amaranth an attractive model for basic plant research but also facilitates further the improvement of this ancient crop by plant breeding.

Palmer Amaranth (Amaranthus palmeri) Identification and Documentation of ALS-Resistance in Argentina

Palmer amaranth has greatly disrupted agricultural practices in the United States with its rapid growth and rapid evolution of herbicide resistance. This weed species is now suspected in Argentina. To document whether the suspected plant populations are indeed Palmer amaranth, molecular comparisons to known standards were conducted. Additionally, these same plant populations were screened for possible herbicide resistance to several acetolactate synthase (ALS)-inhibiting herbicides. Sequencing data confirmed that suspected populations (A2, A3, A4) were indeed Palmer amaranth. Another population (A1) was tested to determine whether hybridization had occurred between Palmer amaranth and mucronate amaranth the native amaranth species of the region. Tests confirmed that no hybridization had occurred and that A1 was simply a unique phenotype of mucronate amaranth. Each population was screened for resistance to imazapic, nicosulfuron, and diclosulam. All Palmer amaranth populations from Argentina were shown to be resistant to at least one ALS-inhibiting herbicide. The populations were then subjected to further testing to identify the mutation responsible for the observed ALS resistance. All mucronate amaranth populations exhibited a mutation previously documented to confer ALS resistance (S653N). No known resistance-conferring mutations were found in Palmer amaranth.

Мульчування як захист енергетичної верби від бур'янів

Species composition of weeds in energy willow plantations was under the effect of such factors as current land use, soil conditions and weed seeds stock. Thus, in control treatment dominated the following species (number of plants per m 2 ): (i) dicots – goosefoot ( Chenopodium album L.) 13.8 and green amaranth ( Amaranthus retroflexus L.) 10.4, with their proportion in total weeds of 30.5%; (ii) monocots – barnyardgrass ( Echinochloa crus-galli L.) 7.6 and foxtail grey ( Setaria glauca L.) 11.5. Together these four weed species accounted for 64.0%. Other dicot species presented in the field were field pennycress ( Thlaspi arvense L.) 5.1 (6.4%), catchweed ( Galium aparine L.) 4.2 (5.3%), black nightshade ( Solanum nigrum L.) 3.4 (4.3%), wild buckwheat ( Polygonum convolvulus L) 7.4 (9.3%), spotted ladysthumb ( Polygonum persicaria L.) 3.2 (4.0%), other 5.3 (6.7%). Total number of weeds in the control treatment made up about 79.6. When using winter wheat straw as a screening material (layer thickness 5 cm) the total number of weeds decreased significantly to 16.8. High efficiency of the mulching marked sprouts of goosefoot, green amaranth (within 90%) and monocots species (85-86%). Whereas the number of black nightshade sprouts (2.6) and field pennycress (1.9) decreased by only 49 and 44%, respectively. The number of spotted ladysthumb (1.3) decreased by 60%. In a treatment with 10 cm of mulching straw, weed sprouts number decreased to 3.3. Dicots reduced their number by 87.5-97.3% and monocots by 97.4-99.1% compared with control treatment. Under these conditions, the number of field pennycress plants was 0.9, green amaranth, barnyard grass and spotted ladysthumb 0.4. When applying 15 cm of mulching straw there were few sprouts of green amaranth, field pennycress (0.1 and 0.2, respectively) left, which impose no significant damage to energy willow plantations. Green mass of weeds on 20-91 July in the control treatment made up 2418 g/m 2 . To this, the most contributing species were wild buckwheat (417 g/m 2 ), black nightshade (336 g/m 2 ) and barnyardgrass (324 g/m 2 ). When applying 5 cm straw, green mass of weeds decreased by 7.7 times (to 314 g/m 2 ). Goosefoot produced the above-ground mass of 117 g/m 2 , which exceeded all other species by more than 3.0 times as much. Covering inter-row space with 10 cm straw reduced weed green mass to 116 g/m 2 , whereas 15 cm straw ­­ to 3 g/m 2 . Treatment with 5 cm straw provided reducing weeds number 4.7 times compared to the control treatment. However, the number of weeds in the growing season made up 16.8 per m 2 . Better results provided screening with 10 and 15 cm of straw, which significantly reduced both the number of weeds and their weight, which makes it possible to prevent energy willow plantations from weed infestation.

The Amaranth Genome: Genome, Transcriptome, and Physical Map Assembly.

Amaranth ( L.) is an emerging pseudocereal native to the New World that has garnered increased attention in recent years because of its nutritional quality, in particular its seed protein and more specifically its high levels of the essential amino acid lysine. It belongs to the Amaranthaceae family, is an ancient paleopolyploid that shows disomic inheritance (2 = 32), and has an estimated genome size of 466 Mb. Here we present a high-quality draft genome sequence of the grain amaranth. The genome assembly consisted of 377 Mb in 3518 scaffolds with an N of 371 kb. Repetitive element analysis predicted that 48% of the genome is comprised of repeat sequences, of which -like elements were the most commonly classified retrotransposon. A de novo transcriptome consisting of 66,370 contigs was assembled from eight different amaranth tissue and abiotic stress libraries. Annotation of the genome identified 23,059 protein-coding genes. Seven grain amaranths (, , and ) and their putative progenitor () were resequenced. A single nucleotide polymorphism (SNP) phylogeny supported the classification of as the progenitor species of the grain amaranths. Lastly, we generated a de novo physical map for using the BioNano Genomics' Genome Mapping platform. The physical map spanned 340 Mb and a hybrid assembly using the BioNano physical maps nearly doubled the N of the assembly to 697 kb. Moreover, we analyzed synteny between amaranth and sugar beet ( L.) and estimated, using analysis, the age of the most recent polyploidization event in amaranth.

PIGMENT CONTENT AND COMPOSITION IN AUTOTROPHIC AND HETEROTROPHIC LEAF TISSUES OF AMARANTH SPECIES A. TRICOLOR L.

At present there is numerous evidence of the antioxidant positive role in the defensive reaction that is capable to protect not only plants, but also humans against oxidative stress. Plant pigments such as natural dyes from leaves, flowers and fruits are known to have high antioxidant activity. Amaranth species A. tricolor L. cultivar ‘Early Splendor’ is a convenient model for the comparative studying of the formation processes of differently colored pigment composition in leaf tissues that differs in the ability to photosynthesize. Leaves of amaranth cultivar ‘Valentina’ were as a standard. The aim of the experiment was a comparative studying of the pigments content: amaranthine, chlorophyll a and b, carotenoids in the cauline leaves of amaranth cultivars ‘Valentina’ and ‘Early Splendor’, as well as in the red and green areas of the leaves. Analysis of the aqueous extract of red Early Splendor amaranth apical leaves showed the presence of betacyanin pigment - amaranthine, in the absorption spectrum in which peak was seen in the green region at 540 nm. In addition to the antioxidant amaranthine there are also antioxidants which might be phenolic glycosides, and ascorbic acid in the extract, the total content of which is almost twice as small as in the leaves of amaranth cauline of this cultivar. Yellow fraction was found in the ethanolic extract of red leaves. Its absorption spectrum had peaks in the blue region at 445 nm and 472 nm and a shoulder at 422 nm that indicated the presence of betaxanthin, betalamic acid or carotenoids. Water-soluble antioxidants - amaranthine and ascorbic acid were found in auline leaves of studied species. Their content in the leaves of Valentina cultivar was higher than in the leaves of cultivar ‘Early Splendor’, and the maximum level of photosynthetic pigments was found in ‘Early Splendor’ leaves. The obtained results showed that the amaranth is a promising source of pigments with the antioxidant activity that can be used for production of food dyes.