Annual Ryegrass Cultivars Research Articles

Metabolite Profiling of Annual Ryegrass Cultivars to Assess Disease Resistance and Susceptibility.

Direct immersion solid-phase microextraction coupled with gas chromatography-mass spectroscopy was used to create chemical fingerprints of annual ryegrass cultivars (Lolium rigidum). Extracts made of the inflorescences of four cultivars and one accession of annual ryegrass were assessed to identify differential metabolites between those resistant to and susceptible to bacterial galls associated with annual ryegrass toxicity (ARGT). Numerous compounds were identified. Principal component analysis showed distinct clustering of metabolites from disease-resistant and disease-susceptible cultivars. Partial least-squares-discriminant analysis identified sterols, esters, aldehydes, and terpenes that correlated with resistance to galls formation. Esters, sterols, phenols, heterocyclics, fatty acids, organofluorides, and siloxanes were predominant in resistant genotypes, whereas alcohols, aldehydes, terpenes, and hydrocarbons were predominant in susceptible genotypes. The identification of differentially expressed metabolites provides potential chemical markers to guide breeding strategies for ARGT resistance in ryegrass.

Comparative physiological and root transcriptome analysis of two annual ryegrass cultivars under drought stress

Annual ryegrass is a widely cultivated forage grass with rapid growth and high productivity. However, drought is one of the abiotic stresses affecting ryegrass growth and quality. In this study, we compared the physiological and transcriptome responses of Chuansi No.1 (drought-tolerant, DT) and Double Barrel (drought-sensitive, DS) under drought stress simulated by PEG-6000 for 7 days. The results showed that Chuansi No. 1 had stronger physiological and biochemical parameters such as root properties, water content, osmotic adjustment ability and antioxidant ability. In addition, RNA-seq was used to elucidate the molecular mechanism of root drought resistance. We identified 8588 differentially expressed genes related to drought tolerance in root, which were mainly enriched in oxidation-reduction process, carbohydrate metabolic process, apoplast, arginine and proline metabolism, and phenylpropanoid biosynthesis pathways. The expression levels of DEGs were consistent with physiological changes of ryegrass under drought stress. We found that genes related to sucrose and starch synthesis, root development, osmotic adjustment, ABA signal regulation and specifically up-regulated transcription factors such as WRKY41, WRKY51, ERF7, ERF109, ERF110, NAC43, NAC68, bHLH162 and bHLH148 in Chuansi No. 1 may be the reason for its higher drought tolerance. This study revealed the underlying physiological and molecular mechanisms of root response to drought stress in ryegrass and provided some new candidate genes for breeding rye drought tolerant varieties.

Effects of different nitrogen doses and cultivars on some nutritive value of annual ryegrass (Lolium multiflorum var. westerwoldicum) silage

Objective: The objective of this study was to determine the effects of different nitrogen doses and cultivars on some nutritive value of annual ryegrass (Lolium multiflorum var. westerwoldicum) silage. Material and Methods: The study was conducted as a field experiment at Ege University, Department of Field Crops during the growing season of 2019-2020. Four annual ryegrass cultivars (Elif, Big Boss, Baquend, and Medoacus) and five nitrogen doses (0, 75, 150, 225, and 300 kg ha-1) were investigated. Some characteristics tested in the experiment were silage dry matter, crude ash, crude protein contents, NDF and ADF contents and silage RFV. Results: The characteristics studied were affected by the applications. While the highest silage dry matter ratio was obtained with 225 kg N ha-1, 300 kg N ha-1 application gave the highest crude protein rate and RFV. The lowest NDF and ADF rates were obtained at a fertilizer rate of 300 kg N ha-1 application. Baquend cv. gave the highest silage dry matter ratio and crude ash ratio.The highest crude protein ratio, lowest NDF and ADF ratios and highest silage RFV were obtained from Elif cv. Conclusion: Elif cultivar had acceptable silage properties at a nitrogen dose of 225 kg ha-1.

Assessing Direct and Residual Effects of Cover Crops on the Soybean Cyst Nematode, Heterodera glycines.

Greenhouse experiments were conducted to determine if cover crops directly decrease population densities of the soybean cyst nematode (SCN), Heterodera glycines, and/or have residual effects on reproduction of the nematode on soybean (Glycine max). Population densities of SCN were not significantly decreased by nine cover crop plants or three cover crop mixes compared with a non-planted soil control in a repeated 60-day-long greenhouse experiment. When susceptible soybeans were grown in the soils after cover crop growth, fewer SCN females formed after three annual ryegrass (Lolium multiflorum) cultivars (Bounty, King, and RootMax), the Daikon radish (Raphanus sativus var. longipinnatus) cultivar CCS779, Kodiak mustard (Brassica juncea), and a mix containing cereal rye, crimson clover (Trifolium incarnatum), plus Daikon radish (cultivars not stated) compared with following the non-planted control. In another repeated experiment, cover crops were grown for 56 days in SCN-infested soil in the greenhouse then exposed to Iowa winter conditions for 28 days to simulate winter termination of the plants. One treatment, a cover crop mix containing 'Bounty' annual ryegrass plus 'Enricher' Daikon radish, had a decrease in SCN population density greater than the non-planted control at the end of the experiment. Significantly fewer SCN females formed on soybeans grown after several cover crops, including the three annual ryegrass cultivars that had the suppressive residual effects in the first experiment. In summary, there were no cover crop treatments that consistently decreased SCN population densities across experiments, and only one cover crop treatment in one experiment significantly reduced SCN population densities more than a non-planted soil control. However, there was a somewhat consistent, adverse, residual effect of cover crops on reproduction of SCN on susceptible soybeans after growth of multiple cover crops.

Physiological and Gene Expression Responses of Six Annual Ryegrass Cultivars to Cobalt, Lead, and Nickel Stresses.

Heavy metals negatively affect soil quality and crop growth. In this study, we compared the tolerance of six ryegrass cultivars to cobalt (Co2+), lead (Pb2+), and nickel (Ni2+) stresses by analyzing their physiological indexes and transcript levels of genes encoding metal transporters. Compared with the other cultivars, the cultivar Lm1 showed higher germination rates and better growth under Co2+, Pb2+, or Ni2+ treatments. After 48 h of Co2+ treatment, the total antioxidant capacity of all six ryegrass cultivars was significantly increased, especially that of Lm1. In contrast, under Pb2+ stress, total antioxidant capacity of five cultivars was significantly decreased, but that of Lm1 was unaffected at 24 h. Staining with Evans blue dye showed that the roots of Lm1 were less injured than were roots of the other five ryegrass cultivars by Co2+, Pb2+, and Ni2+. Lm1 translocated and accumulated lesser Co2+, Pb2+, and Ni2+ than other cultivars. In Lm1, genes encoding heavy metal transporters were differentially expressed between the shoots and roots in response to Co2+, Pb2+, and Ni2+. The aim of these researches could help find potential resource for phytoremediation of heavy metal contamination soil. The identified genes related to resistance will be useful targets for molecular breeding.

Dynamics of forage production in annual ryegrass cultivars / Dinâmica da produção de forragem de cultivares de azevém anual

Annual ryegrass is one of the species that best meets the needs of the farmers in south Brazil during the winter. Many of these cultivars can be found in the market. However, in some cases information on their actual adaptation to each climate situation or production system is unavailable. The present study aimed to evaluate the productive performance of diploid and tetraploid cultivars of annual ryegrass under grazing. The experiment was carried out in the municipality of Pato Branco, State of Paraná (PR), Brazil. The experimental design was a randomized complete block design with 4 replications. The following were the cultivars observed in this study: LE 284, Camaro, Bakarat, Estações, Ponteio and Nibbio (diploids; 2n), Winter Star, KLM 138, Scorpio, Titan, Barjumbo, and Potro (tetraploids; 4n). Mob grazing was used with an entry height of 25 cm and an exit height of 10 cm. It was noted that the cultivars that presented the longest period of pasture use were those that produced the greatest amount of forage. For all cultivars evaluated, the greatest accumulations of forage occurred between August, September, and October. Cultivars Winter Star (4n) and Escórpio (4n) stood out as they yielded the largest forage production. On average, tetraploid cultivars are more productive than diploid cultivars.

Effects of different nitrogen doses and cultivars on fermentation quality and nutritive value of Italian ryegrass (Lolium multiflorum Lam.) silages.

ObjectiveThe fermentation profile and silage quality of 3 Italian ryegrass (Lolium multiflorum Lam.) cultivars (cvs. Devis, Hellen, and Trinova) treated with 5 nitrogen doses (0, 50, 100, 150, and 200 kg/ha) were evaluated.MethodsThe experiment was laid out in split plot in randomized complete block design with three replications. Annual ryegrass cultivars used in this study have been commonly grown in Turkey. Nitrogen doses were set in main plot and cultivars in split plot in the field. Plants were harvested at full-flowering stage with dry matter content about 220 g/kg for first cutting and 260 g/kg for second cutting. Harvested plants were chopped theoretically into 2 to 3 cm lengths for ensiling. Chopped fresh materials were ensilaged by compressing in 2 L plastic jars about 3±0.1 kg.ResultsEffects of N doses on dry matter, neutral detergent fiber, acid detergent fiber, dry matter digestibility, relative feed value, crude protein, pH, ammonia nitrogen, lactic acid, acetic acid, and lactic acid/acetic acid were statistically significant while water soluble carbohydrate, ash and organic matter were not statistically different. Ammonia nitrogen, crude protein, ash, organic matter, lactic acid, and lactic acid/acetic acid were affected by cultivars, but the other parameters were not. Increasing nitrogen applications positively affected the chemical composition of annual ryegrass silage. The significant increase in protein content was remarkable, however, silage fermentation properties were adversely affected by the increasing nitrogen dose.ConclusionIt can be recommended 150 kg/ha nitrogen dose for annual ryegrass harvested at full blooming stage. Even though the silage fermentation properties of the used cultivars were similar, cv. Devis gave better results than the others in terms of silage pH and relative feed value.

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.

58 Effects of Diploid and Tetraploid Annual Ryegrass Cultivars on Cattle Performance, Herbage Mass, and Nutritive Value

Abstract Annual ryegrass (Lolium multiflorum Lam.) can be divided into two cytotypes: diploid (2n = 2x) and tetraploid (2n = 4x). Polyploid versions of a given plant species result in increased seedling vigor, more robust growth and, potentially, greater yield. While most data suggest no difference in yield between diploid and tetraploid cultivars, there is still potential for weight gain advantages thanks to increased non-structural carbohydrates in tetraploid cells. The objectives of this study were to compare weight gain of cattle grazing either diploid or tetraploid cultivars of annual ryegrass. Two diploid annual ryegrass cultivars (Marshall and Tam 90) and two tetraploid cultivars (Jumbo and Nelson) were planted in 0.81-ha pastures, each replicated four times. Four steers (mean initial BW = 214 kg) were randomly assigned to each pasture for an 82-d grazing period. Body weights were recorded starting at day 0 then every 28 days throughout the season. Data were analyzed in the GLM procedure of SAS using a significance level of α = 0.05. There were significant differences between cytotypes with respect to seasonal yield with diploids (9547.90 kg/ha) yielding greater than tetraploids (7762.00 kg/ha). As expected, ADF and NDF fractions were significantly less for tetraploids (ADF; 31.39%, NDF; 31.39%) compared to diploids (ADF; 33.75%, NDF; 53.25%). Tetraploids also contained significantly greater crude protein (13.50%) than diploids (12.90%). Cytotype had no effect on final average daily gain (ADG) (P = 0.9427). However, final ADG was significantly impacted by cultivar (P = 0.0134). Final ADG for Tam 90 (1.10 kg/d) was greater than Marshall (0.92 kg/d). Cattle grazing Nelson (1.04 kg/d) and Jumbo (0.99 kg/d) did not differ. Results show that regardless of differences in seasonal yield and nutritive value between cytotypes, there were no advantages in ADG for cattle grazing either cytotype.

57 Effects of Diploid and Tetraploid Annual Ryegrass Cultivars on Cattle Performance, Herbage Mass, and Nutritive Value

Abstract Annual ryegrass (Lolium multiflorum Lam.) can be divided into two cytotypes: diploid (2n = 2x) and tetraploid (2n = 4x). Polyploid versions of a given plant species result in increased seedling vigor, more robust growth and, potentially, greater yield. While most data suggest no difference in yield between diploid and tetraploid cultivars, there is still potential for weight gain advantages thanks to increased non-structural carbohydrates in tetraploid cells. The objectives of this study were to compare weight gain of cattle grazing either diploid or tetraploid cultivars of annual ryegrass. Two diploid annual ryegrass cultivars (Marshall and Tam 90) and two tetraploid cultivars (Jumbo and Nelson) were planted in 0.81-ha pastures, each replicated four times. Four steers (mean initial BW = 214 kg) were randomly assigned to each pasture for an 82-d grazing period. Body weights were recorded starting at d0 then every 28 days throughout the season. Data were analyzed in the GLM procedure of SAS using a significance level of α = 0.05. There were significant differences between cytotypes with respect to seasonal yield with diploids (9547.90 kg/ha) yielding greater than tetraploids (7762.00 kg/ha). As expected, ADF and NDF fractions were significantly less for tetraploids (ADF; 31.39%, NDF; 31.39%) compared to diploids (ADF; 33.75%, NDF; 53.25%). Tetraploids also contained significantly greater crude protein (13.50%) than diploids (12.90%). Cytotype had no effect on final average daily gain (ADG) (P = 0.9427). However, final ADG was significantly impacted by cultivar (P = 0.0134). Final ADG for Tam 90 (1.10 kg/d) was greater than Marshall (0.92 kg/d). Cattle grazing Nelson (1.04 kg/d) and Jumbo (0.99 kg/d) did not differ. Results show that regardless of differences in seasonal yield and nutritive value between cytotypes, there were no advantages in ADG for cattle grazing either cytotype.

Genetic variability evaluation and cultivar identification of tetraploid annual ryegrass using SSR markers.

Annual ryegrass (Lolium multiflorum) is a widely used cool-season turf and forage grass with high productivity and ornamental characteristics. However, the abundant intra-cultivar genetic variability usually hampers the application of conventional techniques for cultivar identification. The objectives of this study were to: (1) describe an efficient strategy for identification of six tetraploid annual ryegrass cultivars and (2) investigate the genetic diversity based on SSR markers. A total of 242 reliable bands were obtained from 29 SSR primer pairs with an average of 8.3 bands for each primer pair and the average value of polymorphic information content (PIC) was 0.304. The result of analysis of molecular variance (AMOVA) revealed that 81.99% of the genetic variation occurred in within-cultivars and 18.01% among-cultivars. The principal coordinate analysis (PCoA) showed that the first two principal axes explain 8.57% (PC1) and 6.05% (PC2) of total variation, respectively. By using multi-bulk strategy based on different filtering thresholds, the results suggested that bands frequency of 40% could be used as a reliable standard for cultivar identification in annual ryegrass. Under this threshold, 12 SSR primer pairs (00-04A, 02-06G, 02-08C, 03-05A, 04-05B, 10-09E, 12-01A, 13-02H, 13-12D, 14-06F, 15-01C and 17-10D) were detected for direct identification of six tetraploid annual ryegrass cultivars, which could be incorporated into conservation schemes to protect the intellectual property of breeders, ensure purity for consumers, as well as guarantee effective use of cultivars in future.

Production and Nutritional Composition of two Annual Ryegrass Cultivars (Diploid and Tetraploid)

Production and Nutritional Composition of two Annual Ryegrass Cultivars (Diploid and Tetraploid)

Cover Crop Species and Cultivars for Drill‐Interseeding in Mid‐Atlantic Corn and Soybean

Core Ideas Annual ryegrass and orchardgrass performed similarly in field corn. Medium red clover was the most consistent legume species in field corn. No effect of annual ryegrass cultivar was observed in field corn. Annual ryegrass was the most consistent species in soybean. ABSTRACTDrill‐interseeding is becoming a viable method for integrating cover crops in no‐till corn (Zea mays L.) production in the Mid‐Atlantic region. Development of best management practices for drill‐interseeding cover crops into no‐till grain crops requires greater understanding of cover crop performance at the species and cultivar level. Experiments were conducted at multiple Mid‐Atlantic locations (Maryland, Pennsylvania, New York) in two consecutive growing seasons (2013–2014, 2014–2015) to evaluate establishment and performance of drill‐interseeded: (i) grass and legume cover crop species (n = 8) and annual ryegrass [Lolium perenne L. spp. multiflorum (Lam.) Husnot] cultivars (n = 10) in field corn, and (ii) grass and legume cover crop species (n = 6) in soybean [Glycine max (L.) Merr]. Fall biomass production of drill‐interseeded cover crops was higher and less variable among locations in field corn than soybean. Annual ryegrass, orchardgrass (Dactylis glomerata L.), medium red clover (Trifolium pratense L.), and crimson clover (Trifolium incarntum L.) produced greater mean fall biomass than other species in field corn, but variable winter hardiness of crimson clover resulted in less spring biomass than alternative species. No differences were observed among annual ryegrass cultivars. Annual ryegrass, medium red clover, and crimson clover produced greater mean fall biomass than other species in soybean across locations. Our results highlight the viability of a narrow suite of cover crop species for interseeding in Mid‐Atlantic no‐till grain systems and point to the need for development of agronomic practices that facilitate greater niche complementarity between cover and cash crops.

DESARROLLO DE UN SISTEMA EFICIENTE DE REGENERACIÓN VEGETAL in vitro PARA CINCO VARIEDADES ÉLITE DE Lolium multiflorum Lam

<p>The response to <em>in vitro</em> tissue culture of five commercial annual ryegrass cultivars, namely ‘Magnun’, ‘Bargala’, ‘Tetragold’, ‘Hercules’ and ‘Maximus’, was evaluated. Morphogenic callus induction and plant regeneration capacity were assessed in shoot apices cultured on six media formulations that included Murashige and Skoog medium supplemented with casein hydrolyzate and different concentrations of 2,4 phenoxyacetic acid (2,4-D; 1 or 2 mg L<sup>-1</sup>), benzylaminopurine (BA; 2 or 4 mg L<sup>-1</sup>) and adenine (40 or 80 mg L<sup>-1</sup>). Two morphological kind of calli were observed: one of them friable and regenerable and the other watery without regeneration capacity. The highest morphogenic callus formation (37 % in ‘Tetragold’ and ‘Hercules’ varieties <em>vs.</em> 58 % and 65 % in ‘Maximus’ and ‘Magnun’, respectively) was achieved using 2D4B80A medium (2 mg L<sup>-1</sup> 2,4-D, 4 mg L<sup>-1</sup> BA and 80 mg L<sup>-1</sup> adenine). On the other hand, the highest number of regenerated plants per g<sup>-1</sup> fresh weight (FW) of morphogenic callus was 48.71 for ‘Magnum’ shoot apices cultured on 2D4B40A medium (2 mg L<sup>-1</sup> 2,4-D, 4 mg L<sup>-1</sup> BA and 40 mg L<sup>-1</sup> adenine). Regenerated plants grew in soil under greenhouse conditions reached maturity and subsequently produced seeds. The results obtained in this study confirm the suitability of using the shoot tips of <em>Lolium multiflorum</em> as starting material when cultured on the formulation media developed in this study.</p>

Qualidade de sementes de azevém anual e seus impactos no estabelecimento inicial em diferentes densidades de semeadura

Um dos problemas que envolvem a formação de pastagens de inverno no Sul do Brasil é a variação na qualidade das sementes de espécies forrageiras disponíveis no comércio, o que resulta na comercialização de sementes de baixa qualidade. Neste sentido, objetivou-se avaliar a qualidade de lotes de sementes de azevém anual (Lolium multiflorum Lam.) comercializadas no Sul de Santa Catarina (Brasil), nas safras 2013, 2014, 2015 e 2016, bem como seus efeitos no estabelecimento inicial em diferentes densidades de semeadura. As sementes coletadas foram oriundas do excedente de coletas oficiais de amostra de sementes, realizada por Fiscal Estadual Agropecuário em estabelecimentos comerciais. A qualidade das sementes foi avaliada como variável resposta por meio da pureza física, teste de germinação e número de sementes de outras espécies. Para avaliação do estabelecimento inicial em diferentes densidades de semeadura foi utilizado um delineamento experimental em blocos completos casualizados, em esquema fatorial, 2 x 4, com quatro repetições. Os tratamentos consistiram na aplicação de diferentes densidades de semeadura de duas cultivares de azevém anual (Barjumbo e BRS Ponteio): 12,5, 25, 50 e 75 kg/ha. Foram avaliados o número e altura de plantas, número de perfilhos por planta e massa seca de forragem. É fundamental a necessidade do controle externo de qualidade, executado pelo Estado, por meio da atividade fiscal, com vistas a garantir aos agricultores acesso a sementes de alta qualidade, o que tende a melhorar o estabelecimento inicial de pastagens de inverno. Em relação ao aumento gradativo da densidade de semeadura, constatou-se ganhos de produtividade em ambas as cultivares, com as sementes do cultivar Barjumbo apresentando melhor desempenho que as sementes do cultivar BRS Ponteio.

Resistance of Annual Ryegrass Germplasm to a Highly Aggressive New Strain of Blast (Gray Leaf Spot)

ABSTRACTAnnual ryegrass (Lolium multiflorum Lam.) is a highly nutritive, fast-growing, C3 cool-season annual forage. Blast or gray leaf spot is a fungal disease of ryegrass caused by Magnaporthe orygae (anamporph Pyricularia oryzae). The disease kills seedlings as well as adult plants. Blast-resistant annual ryegrass cultivars are not available at present. Therefore, identifying sources of resistance and developing blast-resistant germplasm are priorities to circumvent the devastating disease. Incorporation of germplasm screening in a breeding program requires an efficient, low-cost, and high-throughput evaluation system. Screening methods reported in literature lack both efficiency and throughput capabilities suitable for breeding. The aims in this work were to develop a low-cost, high-throughput phenotyping system, and to screen the annual ryegrass National Plant Germplasm System (NPGS) collection with a highly aggressive, newly isolated M. oryzae strain from naturally infected annual ryegrass plants, which was named MoGA1. Host specificity was tested on four species in addition to annual ryegrass. Extensive damage was caused to perennial ryegrass (Lolium perenne L.) and tall fescue (Lolium arundinaceum (Schreb.) Darbysh), whereas rice (Oryza sativa L.) and orchard grass (Dactylis glomerata L.) exhibited a hypersensitivity response and resisted the infection, suggesting that pathogenicity of the strain was limited to the Lolium genus. A portable low-cost, high-throughput screening system capable of screening 1,536 plants per unit was developed and used to screen 138 ryegrass accessions with MoGA1. Two accessions showed resistance to the pathogen and produced seed. These two entries can be used to incorporate blast resistance in annual ryegrass germplasm.

Cattle Grazing Preference among Tetraploid and Diploid Annual Ryegrass Cultivars

ABSTRACTDetermination of animal preference in the early stages of the evaluation process of new forages may provide insights into potential animal performance as well as plant responses to grazing. A 2‐yr study was conducted at Raymond, MS, to determine grazing preference of cattle between tetraploid and diploid annual ryegrass (Lolium multiflorum Lam.) cultivars and its relationship with morphological and chemical characteristics. Treatments were two tetraploid cultivars, Maximus and Nelson, and two diploid cultivars, Marshall and Gulf, arranged in a 4 × 4 Latin square design experiment. Eight Angus crossbred yearling steers (Bos taurus) (initial body weight of 320 ± 19 kg) were used to determine grazing preference based on herbage disappearance, the Chesson–Manly (CM) index, and amount of time spent grazing. In both years, herbage disappearance was greater for the tetraploid (1380 kg ha−1) than diploid cultivars (895 kg ha−1), with greater CM index for the tetraploid than for the diploid cultivars (8.1 vs. 5.8% in Year 1 and 6.9 vs. 5.5% in Year 2). Also, animals spent about 10% greater time grazing the tetraploid than diploid cultivars during both years. During the first year, the tetraploid cultivars had less neutral detergent fiber (NDF) (556 vs. 589 g kg−1) and less acid detergent fiber (ADF) (341 vs. 359 vs. g kg−1) than the diploid cultivars and Nelson had greater water‐soluble carbohydrate (WSC) concentration (184 g kg−1) than the other three cultivars (152 g kg−1). In the second year, NDF, ADF, and WSC were not different among cultivars. Tetraploid cultivars had a greater proportion of leaf than diploid cultivars. The results indicate that cattle showed greater preference for tetraploid cultivars, which appeared to be linked mainly with pregraze herbage mass and the proportion of leaf.

Dinâmica de produção de forragem de gramíneas anuais de inverno em diferentes épocas de semeadura

A determinação da produção de cada planta forrageira, em cada período, ao longo de sua estação de crescimento, é importante para que se possa orientar o planejamento forrageiro. Objetivou-se com este trabalho avaliar a taxa de acúmulo de matéria seca em diferentes forragens de estação fria em épocas de semeadura distintas. O trabalho foi realizado no período de março a novembro de 2009 para avaliar a taxa de acúmulo diária de forragem em forrageiras anuais de inverno (diferentes cultivares (cvs) de aveia, azevém, centeio, trigo e triticale) em quatro épocas de semeadura (11/3, 8/4, 6/5 e 3/6). As produções de forragem foram convertidas em taxas diárias de acúmulo. Verificou-se interação entre as taxas de acúmulo de forrageiras e épocas de semeadura para todos os caracteres avaliados, indicando flexibilidade no planejamento de implantação das forrageiras. As culturas que tiveram destaque foram as aveias brancas, cvs 'UTF Iguaçú' e 'IPR 126', a aveia preta, cv 'IAPAR 61', as cultivares de azevém e centeio, que apresentaram, em média, produção diária de forragem de 51,4kg ha-1 após a primeira utilização, demonstrando possuírem elevada capacidade de produção e manutenção da produção, especialmente se semeadas até início de maio.

Cover crops of oats, stooling rye and three annual ryegrass cultivars influence maize and Cyperus esculentus growth

Bezuidenhout SR, Reinhardt CF & Whitwell MI (2012). Cover crops of oats, stooling rye and three annual ryegrass cultivars influence maize and Cyperus esculentus growth. Weed Research 52, 153–160.SummaryNo information is available on the effect of cover crops on weed growth in maize production in KwaZulu‐Natal, South Africa. In a field experiment, the influence of two preceding cover crops, stooling rye and annual ryegrass, on the growth of maize and the weed Cyperus esculentus were compared with herbicides and weed control by hoeing. Maize emergence and early growth were delayed in the presence of physical residues of both cover crop species, especially annual ryegrass. Growth of C. esculentus was significantly inhibited in the inter‐row maize planting lines by the cover crops for the first 16 days after maize emergence, but this effect had diminished by day 28. In a pot experiment, the influence of the same two cover crops on maize and C. esculentus growth was evaluated together with oats and two additional annual ryegrass cultivars. Here, the growth of maize and C. esculentus were suppressed, especially by the root residues of the annual ryegrass, in particular the cultivar Midmar. Chemical analysis of the leachate of the root residues indicated the presence of phenolic acids and benzoxazolin‐2(3H)‐one. To achieve effective weed control, a weed management strategy combining the mulch retained on the soil surface, with a possible reduction in the type and amount of herbicide, should be implemented.

Effect of P sources on growth, P accumulation and activities of phytase and acid phosphatases in two cultivars of annual ryegrass (Lolium multiflorum L.)

Recurrent application of animal manure to the soil often results in accumulation of phosphorus (P) in the soil over time. Use of temperate forages like Lolium multiflorum capable of extracting excess P from manure impacted soil is an attractive strategy for P phytoremediation. Two genotypes of L. multiflorum, 'Gulf and Marshall' were grown in soil and hydroponic media containing various concentrations of poultry manure and their P accumulation potential was determined. A decline in the biomass with an increase in manure concentration beyond 10 g kg(-1) soil in Gulf and 25 g kg(-1) soil in Marshall was noticed. Gulf grass accumulated more P content (7 g kg(-1) dry weight) as compared to Marshall (6 g kg(-1) dry weight) in both roots and shoots. Maximum shoot P content was observed in the soil amended with 10 g poultry manure, while root P was highest at the concentration of 50 g poultry manure kg(-1) in the soil. Both cultivars yielded the highest biomass when grown in the presence of 10 g poultry manure in modified Hoagland's media. Presence of chelators in the media did not produce any noticeable effect on P accumulation in either grass and the biomass was appreciably enhanced by all concentrations of the chelators. Gulf and Marshall ryegrass seedlings were grown hydroponically in various poultry manure fractions. Both phytase and acid phosphatase (APase) enzyme activities in the root increased substantially in response to P-sufficient condition. In the presence of various poultry manure fractions, an intermediate level of both enzymes was measured compared to the P-sufficient condition, while the lowest enzyme activity was observed in the absence of any P source in the media. The level of APase and phytase activities was more or less the same in the two grasses under various growth conditions. An additional APase isoform was induced specifically in response to P-starvation from the two grass cultivars. Phytase and APase assays carried out in the P-starved and P-replenished grass seedlings further confirmed that during P deficiency, the enzyme activity was lowest and results of PAGE indicated that an APase isoform was induced under P-starvation.