Ryegrass Samples Research Articles

Effect of Mineral or OFMSW Digestate Fertilization on Ryegrass and Nitrogen Leaching

The current guidelines of waste management are aimed at the recovery and recycling of biowaste while respecting the protection of human health and the environment. The recent European legislation on fertilizers provides for the use of digestates derived from the organic fraction of municipal solid waste (OFMSW). The objectives of this study were to verify the fertilizing effect of three types of OFMSW digestates on the ryegrass culture comparing mineral fertilization and to evaluate the nitrogen lost to leaching in soil diversely fertilized following simulated rainfall. The ryegrass was grown in pots. The soil was fertilized with mineral fertilizer or OFMSW digestates. For each treatment, five mowing procedures were performed on the crop, and the ryegrass biomass production and nitrogen concentration were determined from the ryegrass samples. During the experiment, six rains were simulated, and the leached nitrogen was analyzed. The results showed that: (i) the fertilizing effect of OFMSW digestates on nitrogen nutrition of ryegrass was similar to ammonium sulphate fertilization, confirming the agronomic validity of these by-products to reduce the use of synthetic fertilizers; (ii) soil fertilization with OFMSW digestates had a positive effect limiting nitrogen loss due to leaching compared to mineral fertilization, highlighting the soil-improving properties of these by-products, in particular of the composted digestate.

Differences in the Characteristics and Pathogenicity of Pyrenophora Species Associated with Seeds of Italian Ryegrass.

Pyrenophora is a genus of pathogens that cause leaf damage and a common seedborne fungus of Italian ryegrass (Lolium multiflorum Lam.). To elucidate the main seedborne Pyrenophora species, 36 seed samples of Italian ryegrass were collected; in total, 113 strains, representing 12.3% of all isolated strains (921), were identified as Pyrenophora species using the identity of ITS sequences in NCBI and the similarity of morphological characteristics. P. dictyoides (97) was the most frequent species. By pure culture technique, 24 representative pure isolates were obtained for further study. Based on DNA analysis of multiple loci (ITS, LSU, GPDH, CHS-1, and RPB1) and morphological characters, eight Pyrenophora species were identified, P. avenicola, P. chaetomioides, P. dictyoides, P. lolii, P. nobleae, P. teres, P. triseptata, and P. tritici-repentis; among them, P. avenicola, P. tritici-repentis, and P. triseptata were newly reported on Italian ryegrass worldwide. Seed inoculation showed that P. dictyoides, P. lolii, and P. teres remarkably decreased the final germination percentages and germination indexes compared with control treatments (P ≤ 0.05); and plant inoculation showed that P. dictyoides, P. lolii, and P. nobleae could cause typical brown spot in vivo with a higher infection rate (P ≤ 0.05). In conclusion, pathogenicity tests showed that all Pyrenophora species could both inhibit seed germination and infect Italian ryegrass to different degrees; among them, P. dictyoides was the most important seedborne pathogen based on the combination of its isolation and infection rate, followed by P. lolii and P. nobleae. The data generated in this study are helpful for the accurate identification of Pyrenophora species and the development of seedborne disease management strategies.

Dry Matter Yield and Nitrogen Content Estimation in Grassland Using Hyperspectral Sensor

Estimation of Dry Matter Yield (DMY) and Nitrogen Content (NC) in forage is a big concern for growers. In this study, an estimation model of DMY and NC using Visible and Near Infrared (V-NIR) spectroscopy was developed. An adequate number of grass samples (5078) of perennial ryegrass (Lolium perenne), collected from Dutch grassland in 2019 and 2020 were sensed with a hyperspectral sensor, while grass height was recorded in situ by an ultrasonic sensor mounted on a tractor. The samples were treated with Artificial Intelligence (AI) techniques. PCA based feature selection was applied first, revealing that visible green wavelength (around 500 nm) and red edge wavelength (around 700 nm) were enough to express the overall variability of the dataset. Then, Feature Importance analysis of Random Forest Regressor showed that NIR wavelengths (around 910, 960 and 990nm) were the most sensitive in DMY estimation, while red edge (around 710 nm) and visible orange wavelengths (around 610 nm) were the most related to NC estimation. Finally, SHAP (SHapley Additive exPlanations) analysis was applied to the Random Forest estimation models, resulting in the visualization of wavelength selection, thus assisting in the interpretation of the results and the intermediate processes. Overall, this method can lead to the reduction of the number of wavelengths to be measured in the field and thus, to the possible development of a low cost hyperspectral sensor for the above purposes.

Utilization of Biochar for Eliminating Residual Pharmaceuticals from Wastewater Used in Agricultural Irrigation: Application to Ryegrass

Biochar is known to be a promising material for the treatment of contaminants in wastewater and soil. In this research, wastewater samples collected at the tertiary stage from a WWTP located in the North Bohemia region of Czechia and containing 20 pharmaceutical contaminants were treated with the same biochar (wood and maize cob feedstocks, pyrolysis temperature of 470 °C), but of different doses (0.1 g L−1, 0.25 g L−1, 0.5 g L−1). In this case study, we aimed to verify the impacts of biochar application and/or concentration on the sorption of pharmaceuticals in water. The treated water was later used for irrigating planted (ryegrass taken as the plant model) and unplanted agricultural soils in a pot experiment. Soils and ryegrass samples were examined again for potential pharmaceutical existence, and the soil microbial activities were determined through fluorescein diacetate hydrolytic activities (FDHA). Results showed that most pharmaceuticals concentrations were significantly, but not totally, reduced from the wastewater upon biochar addition. Contaminants such as 3-hydroxycarbamazepine and metoprolol were entirely removed from the wastewater after 0.25 g L−1, whilst bezafibrate did not decline even at 0.5 g L−1. Moreover, the concentrations of pharmaceuticals in ryegrass biomass and soils were dominantly below detection limits or at very low doses. Finally, there were no significant differences in the microbial activities of the soils. This implicates that biochar could be approached as a good substrate for eliminating pharmaceuticals from wastewaters used for agricultural irrigation; however, more similar studies need to be carried out.

First Report of Fusarium meridionale Causing Stalk Rot of Ryegrass in China.

Members of the Fusarium graminearum species complex (FGSC) are the main causing agents of head blight, seedling blight, or stalk rot in wheat and other cereals worldwide. Surveys on species composition and mycotoxin production of FGSC populations have mainly focused on food crops such as wheat, maize, and barley, but little is known about the identity of FGSC pathogens present in pasture grass. In April 2021, a survey of grass diseases in the Hongya County (29.90661 N; 103.37313 E) in Sichuan Province was conducted to understand the etiology of stalk rot in perennial ryegrass (Lolium perenne). It was observed in several pastures that about 10% of yield loss in perennial ryegrass was caused by stalk rot. Affected plant stalks were brown to dark brown in colour and appeared soggy. As infections continued or under conditions of high humidity, some plant stalks also became flattened. Perennial ryegrass samples with symptoms of stalk rot or browning of the stem were collected. Symptomatic tissues were cut into short segments (approximately 5 mm), surface-sterilized in 3% sodium hypochlorite solution for 2 min, rinsed three times with sterile distilled water, air dried, plated onto potato dextrose agar (PDA), and then incubated in the dark at 28 °C. After 3 to 5 days, Fusarium-like fungal colonies with reddish-orange mycelium were collected and transferred to new PDA plates for further purification, and the purified cultures were obtained by single spore isolation. Four uniform isolates were obtained and their colonies on PDA resembled typical FGSC colonies (Leslie and Summerell 2006; O'Donnell et al. 2004). Colonies had an average radial growth rate of 8.5 to 11.0 mm/day at 28 °C in the dark on PDA. Conidial characteristics were studied on Spezieller Nährstoffarmer agar (SNA) as described by Wang et al. (2014). Macroconidia were falcate to almost straight, usually with parallel dorsal and ventral lines, 3- to 5-septate, 20.65 to 55.22 μm in length (average 39.16 μm), and 2.38 to 6.93 μm in width (average 4.42 μm) (n = 200). No microconidia were observed. The pathogenicity of the isolated Fusarium strains was then tested on healthy perennial ryegrass (variety Changjiang 1). Ryegrass plants grown for 2 months were inoculated by punching a hole in the stem using a sterile toothpick, followed by an injection of 20 μL macroconidia suspension at a concentration of 105 spores/mL. Ryegrass stems treated with water served as the control. Twenty plants were included in each treatment. After inoculation, the plants were grown in a growth chamber at 25 °C and 90% humidity for 24 h. Stalk tissues at the wound site turned brown after 3 days and the brown area then extended to regions above and below. No symptoms were observed in the water-treated controls. As well, the same pathogen was reisolated from the infected grass stems, but not from the controls. Thus, the isolated Fusarium spp. are a cause of stalk rot in perennial ryegrass based on the fulfillment of Koch's postulates. To identify the Fusarium spp. to species level, portions of the translation elongation factor 1-α (TEF) gene sequences from all four strains were amplified and sequenced as described by Wang et al. (2015). The obtained sequences were identical, and a sequence of isolate SC1 was submitted to GenBank (accession no. MZ964308). BLASTn searches were conducted on the TEF sequence (607 bp) in two databases, revealing it had 100% similarity to the sequence of Fusarium meridionale strain DS27 (accession no. MN629330) in NCBI and strain NRRL28723 from FUSARIUM-ID (http://isolate.fusariumdb.org/). A concatenated four-gene phylogeny (supplementary figure) resolved SC1 and the type specimens of F. meridionale (NRRL28723, 29010, and 28436) in a monophyletic clade with 100% bootstrap support, confirming that the strain SC1 belongs to F. meridionale. Finally, trichothecene productions of F. meridionale strains were evaluated using rice cultures kept at 28 °C in the dark for two weeks, as described by Desjardins and Proctor (2011). LC-MS/MS analysis indicated that the fungus could produce NIV and 4ANIV in rice cultures with average concentrations of 1400.44 and 3144.10 μg/kg, respectively. To the best of our knowledge, this is the first report of F. meridionale causing disease in perennial ryegrass in China. Further research will be necessary to determine its distribution, aggressiveness, and trichothecene production.

A near infrared spectroscopy calibration for the prediction of fresh grass quality on Irish pastures

The aim of this study was to develop near infrared spectroscopy (NIRS) calibrations to predict quality parameters, dry matter (DM, g kg−1) and crude protein (CP, g kg−1 DM), in fresh un-dried grass. Knowledge of these parameters would enable more precise allocation of quality herbage to grazing livestock. Perennial ryegrass samples (n = 1 615) were collected over the 2017 and 2018 grazing seasons at Teagasc Moorepark to develop a NIRS calibration dataset. Additional samples were collected for an independent validation dataset (n = 197) during the 2019 grazing season. Samples were scanned using a FOSS 6500 spectrometer at 2 nm intervals in the range of 1 100 ~ 2 500 nm and absorption was recorded as log 1/Reflectance. Reference wet chemistry analysis was carried out for both parameters and the resultant data were calibrated against spectral data by means of modified partial least squares regression. A range of mathematical spectral treatments were examined for each calibration, which were ranked in order of standard error of prediction (SEP) and ratio of percent deviation (RPD). Best performing calibrations achieved high predictive precision for DM (R2 = 0.86 SEP = 9.46 g kg−1, RPD = 2.60) and moderate precision for CP (R2 = 0.84 SEP = 20.38 g kg−1 DM, RPD = 2.37). These calibrations will aid the optimisation of grassland management and the development of precision agricultural technologies.

Performance of beef steers continuously stocked on different annual ryegrass cultivars

The objective was to study the performance of beef steers grazing different annual ryegrass cultivars. In 3 consecutive years, steers were continuously stocked on 4 different annual ryegrass cultivars. Cattle were weighed and ryegrass samples were obtained fortnightly. Forage mass, nutritive value, growth rate, animal performance, production per area, DMI, and forage allowance were determined. Mixed models were used to determine the effect of treatment, sampling day, and year on response variables. Differences in forage mass, total ADG, and production per hectare were observed for cultivar and year, and there was a cultivar × sampling day interaction for nutritive value, herbage accumulation, and forage allowance. Limited differences were detected between a late-maturing diploid and mid-to-late- and late-maturing tetraploid cultivars; however, differences were detected with an early-maturing cultivar. Earlyploid production characteristics (early maturity) explain differences in most production variables. Lack of differences between diploid and tetraploids made the decision of choosing a cultivar somewhat easier. Cost of seed might be the major determinant in this decision. There are, however, characteristics of Earlyploid worth considering such as its use when a different cultivar and grazing may have negative effects on early spring growth of summer perennials, staple forages on beef production systems in the Gulf Coast.

Effects of stocking rate on performance of beef steers grazing Nelson annual ryegrass in the deep South

ABSTRACT Objective The objective was to study the effect of stocking rate on animal performance and the performance of Nelson annual ryegrass. Materials and Methods In 3 consecutive years, steers were continuously stocked under 4 different stocking rates. Cattle were weighed and ryegrass samples were obtained fortnightly. Forage mass, nutritive value, grazing days, ADG, production per area, DMI, and forage allowance were determined. Mixed models were used to determine the effect of treatment and year, and regression analyses were conducted for forage data. Results and Discussion Increases in stocking rate decreased (P Implications and Applications Differences in animal production and nutritive value of annual ryegrass due to increasing stocking rates were obtained, and year was an important factor influencing the final data. The experimental evaluation of stocking rates, as with other grazing management techniques, is very dependent on weather and production site.

ДЕРНООБРАЗУЮЩИЕ ЗЛАКОВЫЕ ТРАВЫ ДЛЯ ТАЕЖНОЙ ЗОНЫ

Experimental selection studies were carried out in 2016-2018. in the fields of the Narym Department of Breeding and Seed Production of the Siberian Research Institute of Agriculture and Peat (Kolpashevo, Tomsk Region). The purpose of the research was to study collection samples of lawn grasses capable of effectively using the agro-resource potential of the naturaland climatic conditions in the taiga zone of the Tomsk region. The climate in the research area is sharply continental with long, severe winters and short, but hot and often dry summers. The snow cover lasts about seven months (usually from October to April). The frost-free period is short. Annual precipitation is about 500 mm, including more than 300 mm during the growing season. The sum of air temperatures above 10° C is 1300-1600° C. The soils of the experimental plots are sod-podzolic, sandy loam in granulometric composition, with a humus content in the arable horizon of no more than 2%. As experimental material, 21 samples of bluegrass of three species were studied (8 domestic and 13 foreign varieties); 21 samples of pasture ryegrass (domestic varieties - 3, foreign - 18); 10 samples of four species of bent field of foreign origin; 12 samples of five types of fescue (domestic varieties – 5, foreign – 7). Among the experimental cultivars, the following sources of economically valuable traits were identified: high winter hardiness - all investigated cultivars of bluegrass, bent grass, fescue; grade of perennial ryegrass Yuventus (Denmark); short stature - varieties of meadow bluegrass Yaskia, Limonsine (Germany), Barkenta (Netherlands); ryegrass cultivars of pasture Sport (Poland), Fiesta (USA), Yuventus (Denmark); bentgrass wild populations from Mongolia (K14272, K-14273) and bentgrass from Ukraine (K14265); fine texture source - perennial ryegrass varieties Yuventus, Denmark, Primevere, France, K-14233, Poland.

Lolium multiflorum seed quality analyzed by accredited laboratories in the Rio Grande do Sul State

ABSTRACT: The objective of this research was to carry out a survey, through the levels of physical purity, percentage of pure seeds, number of other seeds, and the physiological quality through germination, in the samples of ryegrass seeds analyzed in laboratories accredited by the Ministry of Agriculture, Livestock and Supply in Rio Grande do Sul. Data from 3959 ryegrass samples analyzed from the period 2014 to 2017 were compiled. Quality of the seeds was presented through the percentage of samples within the standards recommended for commercialization, for the variables germination, pure seeds, seeds of cultivated species, wild, noxious, tolerated and noxiously forbidden, in all factors, cultivar, region of origin, category and crop of seed production. Quality of the lots of ryegrass seeds, analyzed by the laboratories of Rio Grande do Sul, obtained in the harvest of 2013 the lowest percentage of lots approved for commercialization, 57.96%, and the harvest of 2014, 2015 and 2016 with 89.60% 91.39% and 91.34%, respectively. In regions where livestock predominates, the percentage of ryegrass seed lots approved for commercialization was lower.

Hydrolysis of plant biomass at different growth stages using enzyme cocktails for increased fermentable hydrolysates

Abstract In this experiment, optimum experimental conditions for the enzymatic hydrolysis of grass at different stages of growth were obtained by using the Taguchi methodology. Rye grass silage and three growth stages of Italian rye grass samples were used to determine optimum hydrolysis conditions. Five factors (pretreatment, enzyme composition, incubation temperature, pretreatment time, pH) influencing the hydrolysis process were studied at the individual and interactive levels. All selected experimental factors influenced the hydrolysis of grass. At the individual level, pretreatment of grass with NaOH and enzyme composition had the greatest influence (75% and 14.7% of the variance respectively) on enzymatic hydrolysis. Incubation temperature, pretreatment time and pH had influences of 8.1%, 2.2% and 0.055%, respectively. pH and incubation temperature had the most significant interaction effect (65.6%) on enzymatic hydrolysis. The factors with the least individual influence had the most significant interaction effect on enzymatic hydrolysis. Hydrolysis was improved when optimised conditions were applied to different growth stages of Italian rye grass.

ВЫЯВЛЕНИЕ ИСТОЧНИКОВ УСТОЙЧИВОСТИ К ОСНОВНЫМ БОЛЕЗНЯМ У МНОГОЛЕТНИХ КОРМОВЫХ КУЛЬТУР

The relevant task for forage selection is to detect the initial plant source with high resistance to diseases. Phytosanitary monitoring of herbages allows to control the constantly changing epidemiological situation, as well as to identify in time new diseases and diseases which are close to the epidemic threshold. This in its turn allows to determine the forage selection strategy for disease resistance. Positive results in the development of disease-resistant plants couldn’t be possible unless not only an assessment of diseases resistance on special infectious fields is conducted, but also there are active breeding studies. A very valuable source for breeding high disease resistant forages are wild herbs as well as cultivars of forages produced in different climatic zones. The aim of the research was to find plants resistant to two economically important diseases: red clover (Trifolium pratense) resistant to clover rot (Sclerotinia trifoliorum) and ryegrass (Lolium sp.) resistant to leaf spot disease caused by Drechslera siccans. The study was conducted on artificial infectious fields of the immunity laboratory of the Federal Research Center «All-Russian Williams Fodder Research Institute». Data on disease resistance for 85 collection samples of red clover (Trifolium pratense), perennial ryegrass (Lolium perenne) and hybrid ryegrass (Lolium x hybridum) were obtained. Twelve samples of red clover with high resistance to clover rot (Sclerotinia trifoliorum) and Fusarium spp. and one sample with complex resistance to these pathogens were distinguished. An assessment of leaf disease incidence on red clover revealed one sample with high complex resistance to rust and ascochyta blight and three samples with resistance to anthracnose. According to the results of the evaluation of the ryegrass resistance to Drechslera siccans it was found that three samples were not affected by the pathogen. Thus the long-term studies on the assessment of disease incidence of collection plants of red clover and perennial ryegrass make it possible to recommend distinguished samples as sources of increased resistance.

Potential impacts of dietary Lemna gibba supplements in a simulated ruminal fermentation system and environmental biogas production

Abstract Enteric methane production from ruminants contributes to current global warming challenges faced by mankind. Supplements that improve nutritive value of diets are potential mitigating strategies that may reduce enteric methane emissions. This study was, therefore, designed to evaluate the potential of duckweed (Lemna gibba) supplement to reduce enteric methane emissions using an in vitro ruminal gas production technique. In the first of two experiments, Lemna gibba from two water bodies (LG1 and LG2), lucerne and ryegrass samples were analyzed for chemical composition and in vitro ruminal fermentation parameters. In the second experiment, the two Lemna gibba samples were each included in a basal diet at 5, 10, 15, 20 and 25% to create ten dietary treatments. The dietary treatments were also analyzed for chemical composition and in vitro ruminal fermentation characteristics as in the first experiment. Lemna gibba and lucerne fermentation resulted in similar propionate levels. The inclusion of 15% L. gibba had no effect on the ruminal fermentation patterns (volatile fatty acids, acetate:propionate ratio, acetate, propionate and butyrate) and the dry matter and organic matter degradability. These results indicate that L. gibba could be used in ruminant diets as an alternative to grains or concentrates with the added advantage of possibly reducing ruminal methane emissions. Dietary supplementation with L. gibba in ruminant diets could be an environmentally friendly strategy to reduce feed costs and ensure sustainable production.

Predicción de la Composición Química y Fibra Detergente Neutro de Rye Grass Italiano (Lolium multiflorum Lam) mediante Espectroscopía de Reflectancia en Infrarrojo Cercano (NIRS)

El objetivo del presente estudio fue generar ecuaciones de calibración que permitan predecir la composición químico nutricional de la especie forrajera rye grass italiano (RG) (Lolium multiflorum Lam) mediante la técnica de Espectroscopía de Reflectancia en Infrarrojo Cercano (NIRS). Se colectaron 75 muestras de RG de diferentes semanas de corte provenientes de los campos experimentales del Centro de Investigacion IVITA-El Mantaro (Huancayo, Perú), a las cuales se les realizó la captura del espectro mediante equipo NIRS y se hizo el análisis químico de referencia para los componentes proteína cruda (PC), extracto etéreo (EE), cenizas totales (CZ), fibra cruda (FC) y fibra detergente neutro (FDN). Se desarrolló un modelo de calibración y validación mediante mínimos cuadrados parciales (PLS) y como estadísticos de exactitud y precisión se utilizaron el coeficiente de correlación (R), coeficiente de determinación (R2), raíz cuadrada media del error de calibración (RMSEC), raíz cuadrada media del error de predicción (RMSEP), proporción del rango con el error (RER) y desviación residual predictiva (RPD). El análisis proximal promedio fue para PC=19.02%, EE=4.53%, CZ=12.79%, FC=16.50% y FDN=60.98%. Altos valores de R2 y bajos RMSEC y RMSEP fueron obtenidos para PC (0.96, 1.02, 1.19), EE (0.94, 0.29, 1.05), CZ (0.90, 0.57, 0.92) y FDN (0.90, 1.01, 1.25, respectivamente). El mayor RER (22.34) y RPD (4.90) se obtuvo para EE. Se concluye que las ecuaciones de calibración y validación NIRS obtenidas permiten una óptima predicción cuantitativa de PC, EE, CZ y FDN en rye grass italiano (Lolium multiflorum Lam).

Geographic Distribution of Ryegrass Resistent to the Clethodim Herbicide in Rio Grande do Sul1

ABSTRACT Ryegrass is a weed of annual cycle that is present in winter crops, in orchards and vineyards of the South region of Brazil. The species is normally controlled by the glyphosate herbicide, but the continuous use of this product caused the selection of resistant biotypes. The use of ACCase inhibitor herbicides is the main alternative for the control of this species, but it has not been satisfactory in some places, thus causing suspicion of resistance to this action mechanism. Thus, the objective of this paper was to evaluate the occurrence and geographic distribution of ryegrass biotypes that are resistant to the clethodim herbicide in the state of Rio Grande do Sul. For that, seeds of ryegrass plants that survived the application of clethodim were collected in crops from the north region of RS, summing up to a total of 152 samples from 72 cities. The biotypes were submitted to the application of 120 g i.a. ha-1 (maximum registered dose) and 60 g i.a. ha-1 de clethodim (half the maximum registered dose). According to the results, among the samples of ryegrass seeds collected, there were no biotypes resistant to the clethodim herbicide when the maximum registered dose was applied and in the stage of three to four leaves. However, there were biotypes with lower susceptibility that survived half the maximum registered dose.

Estimating genomic heritabilities at the level of family-pool samples of perennial ryegrass using genotyping-by-sequencing.

KeymessageBy using the genotyping-by-sequencing method, it is feasible to characterize genomic relationships directly at the level of family pools and to estimate genomic heritabilities from phenotypes scored on family-pools in outbreeding species.Genotyping-by-sequencing (GBS) has recently become a promising approach for characterizing plant genetic diversity on a genome-wide scale. We use GBS to extend the concept of heritability beyond individuals by genotyping family-pool samples by GBS and computing genomic relationship matrices (GRMs) and genomic heritabilities directly at the level of family-pools from pool-frequencies obtained by sequencing. The concept is of interest for species where breeding and phenotyping is not done at the individual level but operates uniquely at the level of (multi-parent) families. As an example we demonstrate the approach using a set of 990 two-parent F2 families of perennial ryegrass (Lolium Perenne). The families were phenotyped as a family-unit in field plots for heading date and crown rust resistance. A total of 728 K single nucleotide polymorphism (SNP) variants were available and were divided in groups of different sequencing depths. GRMs based on GBS data showed diagonal values biased upwards at low sequencing depth, while off-diagonals were little affected by the sequencing depth. Using variants with high sequencing depth, genomic heritability for crown rust resistance was 0.33, and for heading date 0.22, and these genomic heritabilities were biased downwards when using variants with lower sequencing depth. Broad sense heritabilities were 0.61 and 0.66, respectively. Underestimation of genomic heritability at lower sequencing depth was confirmed with simulated data. We conclude that it is feasible to use GBS to describe relationships between family-pools and to estimate genomic heritability directly at the level of F2 family-pool samples, but estimates are biased at low sequencing depth.Electronic supplementary materialThe online version of this article (doi:10.1007/s00122-015-2607-9) contains supplementary material, which is available to authorized users.

Biogas and Methane Yield from Rye Grass

Biogas production in the Czech Republic has expanded substantially, including marginal regions for maize cultivation. Therefore, there are increasingly sought materials that could partially replace maize silage, as a basic feedstock, while secure both biogas production and its quality.Two samples of rye grass (Lolium multiflorum var. westerwoldicum) silage with different solids content 21% and 15% were measured for biogas and methane yield. Rye grass silage with solid content of 15% reached an average specific biogas yield 0.431 m3.kg-1 of organic dry matter and an average specific methane yield 0.249 m3.kg-1 of organic dry matter. Rye grass silage with solid content 21% reached an average specific biogas yield 0.654 m3.kg-1 of organic dry matter and an average specific methane yield 0.399 m3.kg-1 of organic dry matter.

Morphological identification of the ryegrass hybrid Lolium multiflorum × Lolium perenne and isolation of the pathogen Fusarium pseudograminearum in the Western Cape

Weed resistance to herbicides present one of the greatest current economic challenges to agriculture. Herbicide resistant ryegrass (Lolium spp.) is a serious problem in Western Cape grain-producing areas. Morphological and pathogenic analyses were performed on ryegrass samples. Morphologically, 50% of specimens were classified as rigid ryegrass, 48% as a hybrid, namely L. multiflorum × L. perenne and 2% as perennial ryegrass. Fusarium pseudograminearum (cause of Fusarium crown rot) was isolated from six localities. Pathogencity tests confirmed that F. pseudograminearum isolates obtained from ryegrass and wheat are pathogenic on both crops, indicating that ryegrass can act as an alternative host and a source of inoculum of this important soilborne pathogen. Grass weed infestation can favour the disease, and grass weed control is therefore recommended as part of an integrated strategy to manage crown rot. Knowledge on morphological differences among ryegrass may be important to guide differential weed management of ryegrass. Smother cropping, as part of conservation farming, should receive more prominence to suppress herbicide-resistant ryegrass and simultaneously reduce the occurrence of crown rot.

Comparison of specific methane yield of perennial ryegrass prepared by thermal drying versus non-thermal drying in small-scale batch digestion tests

Dried milled biomass samples are frequently utilised in small-scale batch digestion tests. However, herbage chemical composition can be altered by thermal drying, and this may affect specific methane (CH4) yields. Thus, the specific CH4 yield of herbage pre- and post-ensiling, prepared by two preparation methods were compared. Perennial ryegrass samples were either non-thermally dried (i.e. subject to cryogenic conditions, −196°C) or thermally dried (40°C), prior to milling. Specific CH4 yield was subsequently determined in a small-scale batch digestion test. Herbage pre-ensiling yielded 204 and 243LCH4kg−1VSadded and herbage post-ensiling yielded 212 and 188LCH4kg−1VSadded with non-thermal dried and thermal dried sample preparation methods, respectively. Due to opposing effects of thermal drying on CH4 yields of herbage either pre- or post-ensiling, it is not recommended to use thermal drying. Instead, it is recommended that non-thermal dried herbage samples are used in small-scale batch digestion tests.

Identificação e quantificação de fungos associados a sementes de azevém (Lolium multiflorum Lam.)

O trabalho teve como objetivos, identificar e quantificar os fungos associados a sementes de azevém, comparar a incidência em diferentes meios de cultura, e determinar o número de escleródios de Claviceps purpurea presentes em amostras de sementes. Foram analisadas 37 amostras de sementes de azevém provenientes de municípios do Rio Grande do Sul, Santa Catarina e Paraná. As sementes foram plaqueadas em três meios de cultura: BDA, semi-seletivo de Reis e semi-seletivo de Segalin & Reis, analisando-se a incidência dos fungos. Para detecção de C. purpurea, foram pesados 100g de sementes por amostra e, através de exame visual, foi determinado o número de escleródios. Os fungos detectados foram Alternaria alternata, Bipolaris sorokiniana, Drechslera spp., D. siccans, Fusarium graminearum, Fusarium spp., Aspergillus spp. e Penicillium sp. A incidência de A. alternata variou de 0,0% a 33,7% e freqüência de 89,2% nas amostras analisadas. Para B. sorokiniana a incidência foi de 0,0% a 2,2% e frequência de 62,2%, Drechslera spp., apresentou incidência de 0,0% a 40,3% e frequência de 78,4%. D. siccans a incidência foi de 0,1% a 20,0% e frequência de 100%.Para Fusarium spp., e F. graminearum a incidência foi de 0,0% a 31,0% e 0,0% a 11,3% e frequência de 81,1% e 64,9%, de 0,0% a 43,7% de incidência e 94,6% de frequência para Aspergillus spp. e Penicillium sp. com incidência entre 0,0% a 51,7% e frequência de 91,9%, respectivamente. O fungo C. purpurea foi encontrado em 81,1% das amostras em estudo.