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Studies with dairy cows receiving mixed ration and grazing annual pastures, which have low tiller density, are scarce. This study examined the effect of partial replacement of a total mixed ration (TMR) with annual temperate pasture. Treatments were ad libitum TMR (TMR100), 75% ad libitum TMR + ryegrass (Lolium multiflorum 'Maximus') (pTMR75), and 50% ad libitum TMR + ryegrass (pTMR50). Twelve multiparous Holstein and F1 Jersey x Holstein cows were divided into six groups (experimental units), taking account of milk production (26.6 ± 4.55 kg/day), days-in-milk (129 ± 50.8) and body weight (546 ± 30.6 kg). Treatments were compared using two 3 x 3 Latin square arangements, comprising three 21-day periods (measurements during final 5 days). Herbage DM intake increased from 4.8 kg/day with pTMR75 to 6.7 kg/day with pTMR50. Total DM intake decreased from 19.4 kg/day (TMR100), to 18.1 and 15.8 kg/day (pTMR75 and pTMR50, respectively). Milk production, energy corrected milk production (ECM), and milk fat content were similar between treatments, averaging 25.6, 28.4 kg/day and 44.6 g/ kg, respectively. Ryegrass pastures were able to replace up to 50% of TMR offered to mid lactation dairy cows with no adverse effects on ECM production. [ABSTRACT FROM AUTHOR]

This study determined the effect of different defoliation frequencies in a long-cycle ryegrass cultivar on yield components and the physiological and sanitary quality of seeds. Four defoliation frequencies were applied (without, one, two, and three defoliations). The time between defoliations was 350 degree-days. At the first, second, and third defoliation time, the plants were 15 cm, 20 cm, and 35 cm, respectively, and were lowered to half their height. The yield components and plant structure were evaluated through the tillers, along with the physiological quality of the seeds, which was verified by germination tests, first germination count, accelerated aging, tetrazolium test, field emergence, and weight of a thousand seeds. For the sanitary quality analysis, the percentage (%) of fungi incidence in the seeds was verified. The second defoliation determined the seeds’ high physiological and sanitary quality due to the higher amount of primary and secondary tillers produced concerning the other treatments. However, there was no significant difference for the third defoliation since the aerial tillers issued the same quality of seeds originated from primary and secondary tillers. The average incidence of fungi such as Colletotrichum sp., Fusarium sp., Phoma sp., and Dreshslera spp. was lower in ryegrass plants subjected to three defoliations. [ABSTRACT FROM AUTHOR]

Our aim was to evaluate whether increasing soluble carbohydrates in the herbage by changing the time of the grazing session or including Acacia mearnsii tannin in the diet would affect intake, digestion, N partitioning, and productive performance of dairy cows fed a diet combining ryegrass herbage with partial total mixed ration (PMR). We hypothesized that both strategies could reduce the concentration of NH 3 -N in the rumen, reducing urinary N excretion. Nine Holstein cows were used in a triplicate 3 × 3 Latin square experiment with 3 experimental periods of 22 d. The cows were fed a fixed amount of PMR [60% of the predicted individual dry matter intake (DMI)], and an unrestricted amount of herbage in 1 grazing session of 5 h/d. The treatments were (1) morning grazing session and afternoon PMR meal (AM); (2) morning PMR meal and afternoon grazing session (PM); and (3) morning grazing session and afternoon PMR meal supplemented with 15.0 g of tannins/kg of PMR dry matter (TAN). Milk production was not affected by treatments. Although the protein concentration was lower for TAN than for PM, no differences were detected for the yield of any component between treatments. The concentration of individual or grouped fatty acids in milk fat was not affected by treatments, except for 16:1 cis -9 and Δ9-desaturase ratios 14:1/14:0 and 16:1/16:0, which were lower for TAN. Treatments did not affect total DMI, but PM tended to increase herbage DMI and reduce dry matter and crude protein digestibilities. Treatments did not affect cow eating and ruminating behavior except for the proportion of time spent eating PMR, which was higher for PM and TAN. Although no relevant effects of treatments on ruminal fermentation, purine derivatives excretion in urine, or N excretion in milk were detected, both PM and TAN decreased the total N excreted in urine by an average of 8% compared with AM. In conclusion, changing the grazing session from the morning to the afternoon and including tannins in the diet were effective in decreasing the excretion of urinary N but did not change the productive performance of dairy cows fed PMR and ryegrass herbage. [ABSTRACT FROM AUTHOR]

Air chemistry is affected by the emission of biogenic volatile organic compounds (BVOCs), which originate from almost all plants in varying qualities and quantities. They also vary widely among different crops, an aspect that has been largely neglected in emission inventories. In particular, bioenergy‐related species can emit mixtures of highly reactive compounds that have received little attention so far. For such species, long‐term field observations of BVOC exchange from relevant crops covering different phenological phases are scarcely available. Therefore, we measured and modeled the emission of three prominent European bioenergy crops (maize, ryegrass, and oil‐seed rape) for full rotations in north‐eastern Germany. Using a proton transfer reaction–mass spectrometer combined with automatically moving large canopy chambers, we were able to quantify the characteristic seasonal BVOC flux dynamics of each crop species. The measured BVOC fluxes were used to parameterize and evaluate the BVOC emission module (JJv) of the physiology‐oriented LandscapeDNDC model, which was enhanced to cover de novo emissions as well as those from plant storage pools. Parameters are defined for each compound individually. The model is used for simulating total compound‐specific reactivity over several years and also to evaluate the importance of these emissions for air chemistry. We can demonstrate substantial differences between the investigated crops with oil‐seed rape having 37‐fold higher total annual emissions than maize. However, due to a higher chemical reactivity of the emitted blend in maize, potential impacts on atmospheric OH‐chemistry are only 6‐fold higher. Plain Language Summary: For evaluating the air quality, it is important to know what kind of chemical compounds are emitted from plants into the atmosphere. Such emissions vary widely by plant type and species, including agricultural crops. These differences have not been sufficiently accounted for because long‐term field observations from relevant crops are scarcely available. Therefore, we measured and modeled the emission of three prominent European crops (maize, ryegrass, and oil‐seed rape) for full rotations in north‐eastern Germany. Using the measurements for parametrization, we simulated each measured compound individually and also evaluated the importance of these emissions for air chemistry. We can now demonstrate substantial differences between the investigated crops. For example, on an annual basis, oil‐seed rape emitted 37‐fold more overall emissions than maize, but since the emitted compounds are less reactive, its effect on air chemistry is only 6‐fold higher. Key Points: Emissions differ greatly between crop species in pattern and strength and also vary with weather conditions and phenological developmentPotential impacts on air chemistry vary strongly with species and depend on compound reactivity in addition to source strength of emissionsData suggest that models should better consider growth developmental stages in order to better represent the seasonality of crop emissions [ABSTRACT FROM AUTHOR]

There is a shortage of information about the ryegrass crop (Lolium multiflorum Lam.), especially regarding the suitable sowing rate. Thus, the present work aimed to determine the most adequate sowing rate for tetraploid ryegrass cultivars. A tetraploid ryegrass population was sown at different densities: 150, 300, 600, 900, 1200, 1500, 1800 seeds/m². The number of plants per m², percentage of soil cover, leaf yield and green and dry forage yield were evaluated. The experimental design was randomized blocks with three replications. To observe the behavior of the pasture at different densities for each cut, regression analysis was performed, through which it was possible to verify that the sowing rate has greater influence on the initial cut of the crop. In all the variables analyzed by regression, only the second cut presented a linear trend favorable to the increase in density. In the other cuts, an increase was observed, both in the height of plants and in the yield variables, up to the density of 1500 seeds/m², with a subsequent fall to the highest density, indicating that higher densities may be detrimental to pasture yield. Therefore the density of 1500 seeds/m² is the most suitable for tetraploid ryegrass cultivars. [ABSTRACT FROM AUTHOR]

The objective of this study was to determine the leaf tissue flows in Italian ryegrass (Lolium multiflorum Lam.), in different phenological stages, grazed by lambs, and managed under three herbage allowances (6, 9 and 12 kg DM/100 kg body weight under rotational stocking method. The experimental design was completely randomized, with repeated measures arrangement. Forage allowances determined similar growth and intake flows, actual and potential utilization efficiencies of grass and they were different in the phenological stages of Italian ryegrass. The intake of leaf blade, as a percentage of body weight, was higher in the 12% herbage allowance. Considering leaf tissue flows, Italian ryegrass can be managed in forage allowances that vary between 6 and 12 kg DM/100 kg body weight. [ABSTRACT FROM AUTHOR]

The barley culture has been conquering space in Southern Brazil, being an option for rotation with wheat. One of the main constraints for the increased productivity is the race against weed, especially ryegrass. Therefore, this study aimed to evaluate the barley competitive ability (Hordeum vulgare) against the ryegrass (Lolium multiflorum), in relation to the nitrogen absorption and to measure the density in which the culture is negatively affected. For this, a field experiment was conducted using experimental designs of randomized blocks, where the barley coexisted with different ryegrass densities (0, 4, 16, 32, 64 and 128 m-2). The analyzed varieties were plant height, chlorophyll, number of barley and ryegrass stems, barley and ryegrass dry mass, leaf area, number of spikes, number of grains per spike, the weight of a thousand grains and yield. The ryegrass interferes negatively on the barley's development and productivity, even in low densities, being necessary its control to four plants m-2. [ABSTRACT FROM AUTHOR]

Ryegrass management has been difficult by the occurrence of resistant biotypes to several herbicides with different action mechanisms. Since herbicides mixes and rotations are an important alternative for resistant weed management, the objective of this work was to evaluate the interaction of the dose of the herbicides glufosinate and atrazine on ryegrass control and its seeds' quality exposed to their association. For this study, three experiments were carried out using factorial design in field, laboratory, and greenhouse conditions. Two factors (A and B) were evaluated in each experiment, where factor A and B represented the doses of glufosinate and atrazine, respectively. Ryegrass control was evaluated in field experiment, while germination percentage and Emergence Speed Index (ESI), were obtained in laboratory and greenhouse analyses, respectively. The data were submitted to variance analysis (P<0.05) and the significant results were analyzed through response surface graphs. For ryegrass control data, the effect of the interaction was analyzed by the Colby method; glufosinate provides efficient ryegrass control, but its association with atrazine reduces the efficiency, being characterized as an antagonism between molecules. Glufosinate herbicide application, independent of atrazine presence, reduced the ryegrass seeds quality at the post-flowering stage. [ABSTRACT FROM AUTHOR]

Italian ryegrass (Lolium multiflorum) is a known grass for its high production capacity and feed quality under nitrogen fertilization. Optimizing fertilization can be achieved by applying the associated culture system (mixture) of Italian ryegrass with crimson clover (Trifolium incarnatum). As a result of the studies carried out, in the variant with the sowing proportion of these two species of 50:50 (%), the average production of dry matter in the fertilized variant with N100 was 8.01 t/ha, and the average proportion of crimson clover participation in the floral composition of the mixture was 30%. [ABSTRACT FROM AUTHOR]

Italian ryegrass ( Lolium multiflorum L.) seed crops are often routinely fertilized with a predetermined amount of nitrogen (N) fertilizer in spring. However, nitrate leaching and increasing N fertilizer prices require rationalized fertilizer applications without compromises in seed yield. The objectives of this study were (1) to determine the seed yield response to N fertilization, and (2) to evaluate if NDVI values can reliably predict the N status in Italian ryegrass seed crops. During eight years, field trials were conducted with two cultivars ‘Melclips’ and ‘Melquatro’, and seven N strategies applied after the forage cut as single or split application: 0, 60, 60 + 30, 90, 90 + 30, 120 and 150 kg N ha −1 . NDVI values were obtained with a ‘GreenSeeker’ optical sensor. Maximum seed yield was attained at 141 kg N ha −1 total available N (92 kg N ha −1 fertilized). Higher fertilizations only increased NNI values but not seed yield. Split-application strategies were equal to single-applications in terms of seed yield, which indicates that remedial fertilizations at the two-three node stage are effective. NNI values at all growth stages predicted seed yield adequately: maximum seed yield was attained at NNI values of 0.86 in the 2–3 node stage, 0.72 at the beginning of heading, and 0.59 at full ear emergence. NDVI values were correlated with NNI values, but were also heavily influenced by trial year. Therefore, is it impossible to establish NDVI thresholds to decide on remedial N fertilization. [ABSTRACT FROM AUTHOR]

Background and aims: Nitrogen balances are useful tools to increase our understanding of soil N processes and the efficiency of plants in taking up animal urine-N. This study aimed to investigate the effect of forage type on the fate of autumn-applied urine-N (700 kg N ha). Methods: In a 17-month lysimeter study the recoveries of N in herbage, leachate, nitrous oxide, and soil + roots (at the end of the trial) were determined for three forage types: perennial ryegrass-white clover (RGWC, Lolium perenne L. -Trifolium repens L.), Italian ryegrass (Italian RG, Lolium multiflorum Lam.), and lucerne ( Medicago sativa L.) under simulated autumn grazing. Results: We recovered 81.5-85.5% of the N applied in the urine. Italian RG had the greatest amount of urine-N recovered in the herbage (49.5%) and the least recovered in leachate (16.8%) making it the most efficient of the three forages for utilizing urine-N. For RGWC, herbage and leachate recoveries were 40.1% and 23.7% , respectively. Lucerne was the least efficient with recoveries of N in herbage and leachate equaling 18.4% and 52.5%, respectively. Conclusions: This study demonstrates that Italian ryegrass could offer benefits in reducing urine-N leaching losses through its ability to take up more urine-N over winter. [ABSTRACT FROM AUTHOR]

Soil quality of tillage systems receives much attention worldwide, although few studies attempt to link soil quality to yield. Partial least-squares regression analysis is a suitable method to construct predictive models around plural, highly collinear factors, such as soil quality and its effects on yield. This study aimed at identifying the soil quality properties which best model pasture herbage yield by relating soil quality indicators with variations in yield as a result of soil disturbance caused by tillage. The study was conducted on kikuyu ( Pennisetum clandestinum) over-sown with annual ryegrass ( Lolium multiflorum) using different tillage methods. Tillage methods involved over-sowing kikuyu with ryegrass using a minimum-tillage seed drill, eradication of kikuyu with herbicide and ryegrass sown with a minimum-tillage planter, shallow and deep disturbance, and a control. Most changes in soil quality indicators as a result of soil tillage were observed shortly after tillage and occurred mostly at the 0-100 mm soil layer. Few of these effects were still visible 420 d after tillage. Microbiological indicators changed most in response to the treatments, but unlike the chemical and physical indicators, microbiological indicators have no causal link to pasture production. The contribution of individual soil quality indicators to variance in pasture productivity could not be isolated and should thus be seen as complex processes which affect yield. Although mechanisms of how some soil quality indicators affect yield is clear, more research is required to determine mechanisms of how a combination of multiple soil quality indicators affects yield. [ABSTRACT FROM AUTHOR]

Annual ryegrass (Lolium multiflorumLam.) is a highly nutritive, fast-growing, C3 cool-season annual forage. Blast or gray leaf spot is a fungal disease of ryegrass caused byMagnaporthe orygae(anamporphPyricularia 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 isolatedM. oryzaestrain 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 perenneL.) and tall fescue (Lolium arundinaceum(Schreb.) Darbysh), whereas rice (Oryza sativaL.) and orchard grass (Dactylis glomerataL.) exhibited a hypersensitivity response and resisted the infection, suggesting that pathogenicity of the strain was limited to theLoliumgenus. 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. [ABSTRACT FROM PUBLISHER]

Festulolium is a hybrid between Festuca and Lolium species that has valuable agronomic traits from both grass species. The purpose of our breeding program is to produce hexaploid festulolium that introduces tolerance to summer depression into Italian ryegrass (Lolium multiflorum) by crossing it with tall fescue (Festuca arundinacea). However, we found the DNA ploidy of hexaploids was not stable and was reduced in successive generations. We aimed to find out how to obtain stable high-ploidy festulolium. F1 hybrids of L. multiflorum and F. arundinacea were produced. The F3 generation was produced from putative hexaploid F2 individuals by open pollination. The F4 to F6 generations were obtained by polycrossing. The DNA ploidy levels of F2 to F6 individuals were estimated by flow cytometry. Cytological characteristics of the F5 and F6 individuals were investigated by FISH and GISH. The DNA ploidy level of hexaploid festulolium was reduced and stabilized at almost the same level as a tetraploid. Seed fertility was inversely correlated with an increase in ploidy level. GISH revealed no preferential Lolium transmission. FISH with a telomere probe revealed that counting the exact number of chromosomes in festulolium was difficult. DNA ploidy level was strongly correlated with the number of chromosomes. [ABSTRACT FROM AUTHOR]

Three quick tests were evaluated for detecting glyphosate-resistant biotypes of Italian ryegrass and perennial ryegrass. Biotypes of these two species were used that were 13.4 and 7.3 times more resistant to glyphosate, respectively, than susceptible biotypes when assessed using a sprayed pot study. One assay exposed germinating seeds of resistant and susceptible populations for 8 days to different concentrations of glyphosate. Measurements of reduction in seedling root growth gave an estimate of resistance magnitude of 10.8 and 8.9 for Italian ryegrass and perennial ryegrass, respectively, similar to that from the sprayed pot study. Two other assays were tested and were able to differentiate resistant and susceptible biotypes. One measured the relative levels of shikimic acid in leaves following exposure to glyphosate; four to seven times more shikimic acid accumulated in glyphosate-susceptible populations of Italian and perennial ryegrass than in resistant populations. The other assay involved growing tillers of the plants in glyphosate solutions and the results showed that at glyphosate concentrations of 10 and 40 mg/L, the plantlets of resistant plants showed negligible visual injury and growth reduction compared with susceptible ones. Results obtained from these assays were not affected by whether the glyphosate formulation used was an isopropylamine salt or potassium salt. [ABSTRACT FROM AUTHOR]

The objective was to evaluate the effects of times of emergence of the weed ryegrass species and wild radish on barley. The experiment was conducted in a randomized block design, arranged in a 2x5 factorial design, with three replicates. In factor A were allocated the competing species (ryegrass and wild radish) and in factor B the emergence periods (14 and 7 days before, on the same day, 7 and 14 days after crop emergence). At the beginning of barley flowering, the following variables were quantified: plant height, number of stalks or stems, leaf area, and shoot dry mass of crop and weeds. All barley variables had increased in value with the delay in weed emergence. The species, cultivated or weeds, that emerged earlier showed greater competitive ability, dominating the environment when emerging 14 days before each other. The later the emergence of weeds with respect to the crop, the less the interference they cause, and, thereby, the crop presents a greater ability to compete with the weeds for available resources in the environment. [ABSTRACT FROM AUTHOR]

The objective in this study was to characterize the productive potential, monthly yield distribution, and forage plantpart and botanical composition of black oats and annual ryegrass under harvest strategies in São Paulo. The experimental design was completely randomized with treatments corresponding to the combination among stand composition (exclusive oats, exclusive annual ryegrass, or oats + ryegrass, O+R) and harvest strategies (at 95% LI or every 30 days of regrowth, FIXED), in a factorial arrangement with three replications. Stands managed by LI accumulated 1580kg DM ha-1 harvest-1, and those managed by FIXED 2020kg DM ha-1 harvest-1. Leaf proportion was higher in ryegrass (70%), followed by O+R (64%) and oat (52%). Swards managed by LI had higher proportion of leaves and less stem than those harvested at FIXED intervals. The proportion of ryegrass was higher under the LI management (64%), than under the FIXED (70%). Over time there was the replacement of oats by ryegrass in the mixed canopy composition. Exclusive ryegrass stands are recommended. Both harvest strategies can be adopted for these winter forages in integrated systems of agriculture and livestock. [ABSTRACT FROM AUTHOR]

This study tested the hypothesis that different sward structures, which were constructed by varying the pre- and post-grazing sward heights of annual ryegrass pasture ( Lolium multiflorum Lam.) in southern Brazil, affect the short-term intake rate ( STIR) by dairy cows. Treatments consisted of four sward-management strategies defined by a combination of two pre- (25 and 15 cm) and two post-grazing sward heights (10 and 5 cm): 15-05, 15-10, 25-05 and 25-10. A completely randomized block design with four replicates was used for the experimental design. The STIR was determined by the double-weighing technique. Jaw movements were evaluated using automatic recorders ( IGER Behaviour Recorder). The results showed that treatment 25-10 allowed the animals to collect more herbage with a greater bite mass and thus resulted in a greater STIR. Treatments in which sward height was reduced to 10 cm generally favoured the ingestion process than treatments with a post-grazing sward height of 5 cm. [ABSTRACT FROM AUTHOR]

Abstract: The combined use of plants and associated microorganisms has great potential for remediating soil contaminated with organic compounds such as pesticides. The objective of this study was to determine whether the bacterial inoculation influences plant growth promotion and chlorpyrifos (CP) degradation and accumulation in different parts of the plant. Ryegrass was grown in soil spiked with CP and inoculated with a pesticide degrading bacterial strain Bacillus pumilus C2A1. Inoculation generally had a beneficial effect on CP degradation and plant biomass production, highest CP degradation (97%) was observed after 45days of inoculation. Furthermore, inoculated strain efficiently colonized in the rhizosphere of inoculated plant and enhanced CP and its primary metabolite 3,5,6-trichloro-2-pyridinol (TCP) degradation. There was significantly less CP accumulation in roots and shoots of inoculated plants as compared to uninoculated plants. The results show the effectiveness of inoculated exogenous bacteria to boost the remediation of CP contaminated sites and decrease levels of toxic pesticide residues in crop plants. [Copyright &y& Elsevier]

The potential impact of postdispersal seed predation by the field cricket, Teleogryllus emma (Ohmachi et Matsuura), on the seedling emergence of Italian ryegrass ( Lolium multiflorum Lam.), a non-native grass weed in Japan, was determined. The relationship between cricket density and the proportion of seedling emergence was investigated by conducting manipulative experiments in duplicate, using enclosures. One-thousand seeds of Italian ryegrass were exposed to adult crickets at different densities (zero, one, two, four and eight individuals per 2.25 m2 enclosure) for 2 weeks. The proportion of seedling emergence decreased with increasing cricket density. The proportion of seedling emergence in the enclosures without the crickets was 90.9-97.2%, whereas the seedling emergence in the enclosures with eight crickets greatly decreased, to 0.5-2.5%. These results suggest that postdispersal seed predation by T. emma can substantially decrease the abundance of Italian ryegrass at an early life stage and reduce its population in environments with a high density of crickets. [ABSTRACT FROM AUTHOR]

Forage breeding is key to improving livestock management and the objective of this study was to evaluate Pearson's simple correlation between the yield components of forage dry matter and grain in ryegrass. Five ryegrass genotypes, planted on five dates and cut from one to four times, were set out in a complete randomized block design. Ryegrass forage with a lower dry matter production, but with more leaves, fewer culms, higher protein and less fiber content, produces a higher grain yield, spike length, thousand grain weight and lower spike number. The association between the yields of dry matter and grain components is an important criterion for selecting ryegrass genotypes, since grain yield is positively correlated with leaf dry matter, gross protein content, spike length and thousand grain weight. [ABSTRACT FROM AUTHOR]

This study evaluates the balance of species 2 mo after sowing, its effects on seasonal and annual dry matter accumulation of Plantago lanceolata L. 'Ceres Tonic' sown in pure stands, in binary mixtures with three grasses, and different initial growth rates: annual ryegrass (Lolium multiflorum Lam.), tall fescue (Festuca arundinacea Schreb.), and orchard grass (Dactylis glomerata L.). Plantain monocultures were sown at three densities (4, 8, and 12 kg seed ha-1), while halved densities were used in the mixtures. Each grass was sown at the density that is typical for the region (annual ryegrass = 30, tall fescue = 15, and orchard grass = 6 kg seed ha-1). The trial was carried out in Balcarce (37°45' S, 58°18' W; 130 m a.s.l.), Argentina in 1.4 x 5 m plots sown in April 2005 with a randomized complete block design, a factorial arrangement of pasture type and plantain sowing density, and seasons as a measurement repeated over time. Plant density 2 mo after sowing was not a good estimator of the balance between species for all pasture types at the end of the first year. Total forage accumulation throughout the experimental period was affected by pasture type (p = 0.08) and plantain sowing density (p < 0.05), but not by their interaction (p > 0.05). The plantain and annual ryegrass mixture accumulated 28% more biomass than the mean biomass of all the other pastures (7948 ± 647 vs. 6204 ± 502 kg DM ha-1) mainly because of its higher yield in fall and winter. Total precipitation during the year under study was 15% lower than the historic average so that higher accumulations could be expected in years with higher precipitation. [ABSTRACT FROM AUTHOR]

In Mediterranean countries, forage grasses and legumes are commonly grown in mixture because of their ability to increase herbage yield and quality compared with monocrop systems. However, the benefits of intercropping over a monocrop system are not always realized because the efficiency of a grass-legume mixture is strongly affected by agronomic factors. The present study evaluated productivity, N fixation, N transfer, and N recovery of berseem clover ( Trifolium alexandrinum) grown in pure stand and in mixture with annual ryegrass ( Lolium multiflorum) under high or low defoliation frequencies and varying plant arrangements (sowing in the same row or in alternating rows). On average, the berseem-ryegrass mixtures resulted in a greater yield and N yield than the monocrops. When mixed together, ryegrass was more efficient than berseem at absorbing soil N, increasing the reliance of berseem on N fixation. Both defoliation management and plant arrangement affected forage yield and the quality of the mixture, modifying the proportion of the two components, the N content of the forage, and the symbiotic N fixation of the legume. Reducing the proximity between plants of the two species may benefit the weaker component of the mixture. No apparent transfer of fixed N from berseem to ryegrass was detected. [ABSTRACT FROM AUTHOR]

Cool-season grasses commonly harbor fungal endophytes in their aerial tissues. However the effects of these symbionts on soil microbial communities have rarely been investigated. Our objective was to explore microbial community responses in soils conditioned by plants of the annual grass Lolium multiflorum with contrasting levels of infection with the endophyte Neotyphodium occultans. At the end of the host growing season, we estimated the functional capacity of soil microbial communities (via catabolic response profiles), the contribution of fungi and bacteria to soil activity (via selective inhibition with antibiotics), and the structure of both microbial communities by molecular analyses. Soil conditioning by highly infected plants affected soil catabolic profiles and tended to increase soil fungal activity. We detected a shift in bacterial community structure while no changes were observed for fungi. Soil responses became evident even without changes in host plant biomass or soil organic carbon or total nitrogen content, suggesting that the endophyte modified host rhizodepositions during the conditioning phase. Our results have implications for the understanding of the reciprocal interactions between above and belowground communities, suggesting that plant-soil feedbacks can be mediated by this symbiosis. [ABSTRACT FROM AUTHOR]

set of 15 Italian ( Lolium multiflorum), three hybrid ( L. boucheanum) and 33 perennial ryegrass ( L. perenne) cultivars were evaluated for their rust susceptibility in the field. The cultivars were grown in 2001, 2004 and 2007 at 29, 32 and 27 European sites, respectively. Rust incidence was scored during different growth cycles using a scale from one (no rust) to nine (susceptible). Crown rust ( Puccinia coronata f. sp. lolii) was the most frequently observed rust species on Italian, hybrid and perennial ryegrass during all three experimental years. There was a highly significant difference in mean crown rust scores among Italian and perennial ryegrass cultivars, respectively, in each of the 3 years. The ranking of the cultivars was very consistent across the different sites within each year (with some exceptions), despite a significant interaction of cultivar response with sites. Moreover, the rank order correlations of mean cultivar rust scores were highly significant ( r > 0.9) between the years. Stem rust ( P. graminis f. sp. graminicola) occurred almost exclusively on perennial ryegrass. The cultivars showed significant variation in stem rust susceptibility. Rank order correlations of mean cultivar stem rust scores were mostly significant between sites within each year and highly significant between the years. The ranking of perennial ryegrass cultivars was different depending on whether crown or stem rust was scored. However, the rank order correlation between the mean disease scores of the cultivars for the two pathogens was low but still significant. At a particular site the assessment of crown or stem rust was in most cases very consistent over the period of experimentation. Therefore there was no evidence that rust resistance of an individual cultivar was overcome by the rust pathogen at a particular site over the 7 years of experimentation. [ABSTRACT FROM AUTHOR]

Transgenic Italian ryegrass plants expressing the betaine aldehyde dehydrogenase gene of zoysiagrass (ZBD1) were produced via particle bombardment of embryogenic calluses. Although the growth of both non-transgenic and transgenic plants expressing ZBD1 was inhibited under salt stress, isolated tillers of the transgenic plants showed better re-rooting ability in vitro in the presence of 300 mM NaCl. Chlorophyll fluorescence values of the transgenic plants declined under salt stress, but were significantly higher than those of non-transgenic plants under salt stress, indicating the improved salt stress tolerance of transgenic plants. [ABSTRACT FROM AUTHOR]

Mixed swards of white clover–grass mixtures in highly productive environments often fail to reach the minimum recommended annual clover proportion of about 0·30. This study assessed the effect on clover content and total dry matter (DM) yield of two spring N applications (0 and 45 kg N ha−1) and two distances between drilled grass-rows (0·18 and 0·36 m) over 3 years for mown swards of white clover–Italian ryegrass ( Trifolium repens–Lolium multiflorum) in binary mixtures in northern Italy. An additional aim was to determine the advantage of association of grass–clover compared with grass and clover monocultures. On average, N fertilization of mixtures resulted in almost 9% higher total yield ( P < 0·01; mean response = 18·1 kg of total DM per kg of N) but decreased the clover proportion (0·250 vs. 0·312). Wider grass-row spacing increased clover proportion (0·327 vs. 0·234; P < 0·01) with no reduction of total DM yield. N fertilization × grass-row spacing interaction occurred only for clover content ( P < 0·01). Without N fertilization, mixtures out-yielded clover and grass pure stands. With N fertilization, at double rate to pure grass, yields from mixtures were greater than from clover and comparable to Italian ryegrass. [ABSTRACT FROM AUTHOR]

The objectives were evaluating the combined effects of different rates of both inoculum (Rhodococcus fascians) and nitrogen on forage production of grasses and to perform a cost - benefit economic analysis. The species analyzed were Avena sativa L, Lolium multiflorum Lam, and Triticum durum L through the following treatments: inoculation, nitrogen fertilization (0, 30, 60 kg N ha-1) and a combination of inoculation and fertilization. The species were established under irrigated conditions in a clay loam soil with 6.7 pH, and 0.34 % organic matter. The microorganism was sprayed on the seed and later, on the plants after each forage harvest. Forage production was evaluated in terms of metric tons (t) of dry matter (DM) ha-1. The economic study was performed using marginal analysis, where the indicators were cost variables, forage production and net benefits. The experiment was carried out using a completely randomized design with a 2x3x3 factorial arrangement with four replications, where the first factor was inoculation; the second factor, species; and the third factor, N rate. The results show that the combined use of an inoculum and 30 kg N ha-1 produces 50 % more DM (approximately 11 t) than when only N is used, especially in Avena sativa L. and Lolium multiflorum Lam. The economic analysis showed that the best treatment was inoculation plus 30 kg N ha-1 for Avena sativa L, presenting a marginal return rate of over 60 %. [ABSTRACT FROM AUTHOR]

Italian ryegrass ( Lolium multiflorum Lam. ssp. italicum Volkart ex Schinz et Keller) thrives well in permanent grassland in mild and moist regions of Switzerland. Ecotypes of Italian ryegrass from Swiss permanent meadows have often been used successfully as the base material of breeding programmes. However, their agronomic performance per se has never been studied in detail. Therefore, field trials were conducted to assess the potential of this semi-natural genetic resource for use in breeding. Twenty ecotype populations were collected in different geographical regions in 2003 and seed was increased. Plot trials with 20 ecotype populations were conducted 2005–2007 at three locations, supplemented by row trials at two additional locations, and including four currently recommended cultivars as controls. Average performance in terms of yield, vigour and resistance to snow mould of ecotypes was superior to the cultivars. Depending on the characteristic, between three and 16 of the 20 ecotypes performed significantly better than the cultivars mean. However, resistance against crown rust of all ecotypes was significantly poorer than that of the cultivars. Correlation and regression analysis showed that more eastern and more northern collecting sites harboured better performing ecotypes. However, the most consistent site related factor favouring performance of the ecotypes in terms of yield, vigour, snow mould and Xanthomonas resistance was a low abundance of species which are typical of Arrhenatheretum type meadows. Data from the plot trials were related to results obtained with spaced plants at a single site, either in a seedling nursery or in the greenhouse. Resistance against crown rust was extremely well predicted by spaced plant observations. Xanthomonas resistance observed after artificial inoculation in the greenhouse was also significantly, but less closely correlated with field observations. An early date of ear emergence as observed on spaced plants was associated with high annual yield in the plot trials. It is concluded that in intensively managed habitats, natural selection has resulted in ecotype populations of Italian ryegrass which are highly promising for use in breeding. Individual plant selection for resistance can be expected to efficiently reduce their high susceptibility to crown rust. [ABSTRACT FROM AUTHOR]

The objective of this study was to estimate lower base temperature Tb of three diploid (Comum, Fepagro São Gabriel, and LE 284 and two tetraploid (Avance and INIA Titán) ryegrass genotypes. With the estimated Tb, it was also possible to investigate if these genotypes may have seasonal production, which helps in programming herds feeding schedules. Five sowing dates (11/05, 07/06, 05/07, 09/08 e 01/09/2007) were performed in Santa Maria, RS, Brazil. Two methods were used to estimate Tb: least deviation method and relative development method. Tb values varied from 7.0 to 8.5°C for diploid genotypes and from 9.0 to 10.6°C for tetraploid genotypes, depending upon the method. Diploid ryegrass germoplasm have no risk of seasonal decrease in forage production, whereas tetraploids, mainly Avance, may have their growth and development decreased from June to August in Santa Maria because of minimum air temperature. [ABSTRACT FROM AUTHOR]

Farm soil and artificial soil were mixed separately with Pb/Zn mine tailings and placed in the ratios (w/w) of 0, 12.5, 25, and 50% in pots, together with 0.33 g KH2PO4 and 0.35 g urea/pot. Each pot contained 15 ryegrass seedlings (Lolium multiflorum) and 7 earthworms (Pheretima sp.). At the end of the experiment (after the third harvests of ryegrass), the earthworms were all found to be alive and burrowed completely at the bottom of the pots in all treatments. Earthworm activity increased plant biomass significantly in artificial soil/tailings mixtures in the second and third harvests as compared with the control (without addition of earthworms), but not in the farm soil/tailings mixture. The biomass of ryegrass in both soil/tailings mixtures decreased with increase of tailings, especially those containing 50% tailings. In general, the plant biomass obtained from farm soil/tailings mixtures was lower than that from artificial soil/tailings mixtures. Earthworm activity did not significantly increase DTPA-extracted Zn or Pb, in both soil/tailings mixtures. However, the concentrations in farm soil/tailings mixtures were lower in the second and third harvests, compared with the first harvest. The Zn and Pb uptake by ryegrass shoots in the two soils/tailings mixtures did not increase significantly (compared with the control) in the first and second harvests. However, in the third harvest, Zn and Pb uptake increased significantly in farm soil/tailings mixtures, but decreased significantly in artificial soil/tailings mixtures (compared with the control). The results indicated that the presence of earthworms and sequential plant harvesting could be a viable strategy for the remediation of Pb/Zn tailings. [ABSTRACT FROM AUTHOR]

This study investigated the effects of crown rust (caused by Puccinia coronata f.sp. lolii) in Italian ryegrass ( Lolium multiflorum) on plant growth and interference ability in the post-epidemic generation. Rust-infected Italian ryegrass plants produced seeds with lower weights than healthy plants (on average proportionately 0·36 lower). Furthermore, the early seedling vigour of plants from rust-infected parents was reduced by 0·50 compared with seed from healthy parents. Under disease-free conditions in the post-epidemic generation, mature plants from rust-infected parents produced 0·13 less shoot dry weight, 0·15 fewer tillers, 0·11 fewer leaves and 0·25 less leaf area than plants from healthy parents. As such, the effects of crown rust in Italian ryegrass persisted for at least one post-epidemic generation. Under rust-infected conditions in the post-epidemic generation, however, the difference in performance between plants from healthy and rust-infected parents was minimal. This suggests that any advantage plants gain from having healthy parents, compared with rust-infected parents, might be lost when the post-epidemic generation is grown under conditions of rust infection. Irrespective of rust infection in the post-epidemic generation, the magnitude of intra-specific interference was greater in monocultures of Italian ryegrass from healthy parents than in those from rust-infected parents. However, the magnitude of inter-specific interference and the relative interference ability of plants of rust-infected and healthy parents did not differ. The implications of these results to plant ecology are discussed. [ABSTRACT FROM AUTHOR]

New molecular markers derived from expressed sequence tag (EST) sequences were mapped on linkage maps of Italian ryegrass by a two-way pseudo-testcross strategy. cDNA sequences were obtained from various tissues of Italian ryegrass ( Lolium multiflorum) and converted into cleaved amplified polymorphic sequence (CAPS) markers. Of 260 EST primer pairs that amplified a single band, 74 generated bands that showed clear polymorphisms among individuals of an F1 mapping family. Of the 74 polymorphic marker loci, 69 were mapped on an Italian ryegrass linkage map previously constructed using amplified fragment length polymorphism (AFLP), restriction fragment length polymorphism (RFLP), and simple sequence repeat (SSR) markers. The newly-developed EST-CAPS markers would be useful as an efficient tool to identify genetic markers and to identify candidate genes for quantitative trait loci (QTLs) associated with important traits in Italian ryegrass. [ABSTRACT FROM AUTHOR]

In this study, we evaluated the release of diclofop-methyl and triasulfuron from the roots of foliar-treated ryegrass and wheat. The study with 14C-diclofop-methyl indicated a basipetal translocation of foliar-applied herbicide in wheat and ryegrass. No root exudation from 14C-diclofop-methyl-treated wheat plants was observed, while 20 days after treatment (DAT) 0.2–0.9% of radioactivity absorbed by ryegrass was found exuded in the growing medium. Root exudation was stimulated three to six times by the presence of untreated wheat or ryegrass sharing the growing medium with diclofop-methyl-treated ryegrass. No subsequent uptake of exuded radiolabel by untreated plants (ryegrass or wheat) in the same pot with 14C-diclofop-methyl-treated ryegrass was observed. The study with 14C-triasulfuron indicated a basipetal translocation of foliar-applied herbicide in wheat and ryegrass and also into the growing medium. By 20 DAT, 0.5–4.2% of radioactivity absorbed by wheat or ryegrass was found exuded in the growing medium. The presence of untreated plants (wheat or ryegrass) in the same pot as triasulfuron-treated ryegrass or wheat induced exudation seven to 32 times more. The study also revealed a subsequent uptake of exuded compounds by untreated wheat or ryegrass sharing the medium of 14C-triasulfuron-treated plants. This study has demonstrated for the first time that the root exudation of exogenous compounds can be related to plant arrangement in pots. The implication is that herbicide root exudation and transfer, a form of allelopathy, could be significant in the field. A precise estimation of environmental fate, unexpected ecological side effects and residual activity of herbicides may require quantification of such exudation. [ABSTRACT FROM AUTHOR]

The first backcross breeding programme for the transfer of freezing-tolerance genes from winter hardy Festuca pratensis to winter-sensitive Lolium multiflorum is described. A partly fertile, triploid F1 hybrid F. pratensis (2n=2x=14) × L. multiflorum (2n=4x=28) was employed initially, and after two backcrosses to L. multiflorum (2x) a total of 242 backcross two (BC2) plants were generated. Genomic in situ hybridisation (GISH) was performed on 61 BC2 plants selected for their good growth and winter survival characters in the spring following one Polish winter (2000–2001). Among the winter survivors, diploid chromosome numbers were present in 80% of plants. An appropriate single Festuca introgression in an otherwise undisturbed Lolium genome could provide increased freezing tolerance without compromise to the good growth and plant vigour found in Lolium. Among all the diploids, a total of 20 individuals were identified, each with a single F. pratensis chromosome segment. Another diploid plant contained 13 Lolium chromosomes and a large metacentric F. pratensis chromosome, identified as chromosome 4, with two large distal Lolium introgressions on each chromosome arm. Three of the diploid BC2, including the genotype with Festuca chromosome 4 DNA sequences, were found to have freezing tolerance in excess of that of L. multiflorum, and in one case in excess of the F. pratensis used as control. A detailed cytological analysis combining GISH and fluorescence in situ hybridisation analyses with rDNA probes revealed that the other two freezing-tolerant genotypes carried a Festuca chromosome segment at the same terminal location on the non-satellite arm of Lolium chromosome 2.Heredity (2006) 96, 243–251. doi:10.1038/sj.hdy.6800787; published online 1 February 2006 [ABSTRACT FROM AUTHOR]

Bacterial wilt caused by Xanthomonas translucens pv. graminis ( Xtg) may lead to severe damage and substantial yield losses in Italian ryegrass, Lolium multiflorum Lam. To identify candidate genes for marker-assisted breeding and to investigate the molecular basis of the host-pathogen interaction, this study focused on searching the ryegrass genome for resistance genes and key signal transduction elements in the defence response. cDNA-amplified fragment length polymorphism (AFLP) was used to analyse differentially expressed genes at six time-points after infection in a partially resistant genotype of L. multiflorum infected with Xtg. A total of 87 selective primer combinations resulted in 173 differentially expressed transcript-derived fragments (TDF) out of which 37 TDFs were isolated. Database searches revealed sequence homologies of various TDFs to sequences such as ERBP-transcription factors, an TGF- β receptor interacting protein, a terpene synthase and various other genes expressed in response to bacterial and fungal infection. Reverse transcription-polymerase chain reaction (RT-PCR) and quantitative RT-PCR (qRT-PCR) confirmed the expression patterns found by cDNA-AFLP. The TDFs identified represent candidate genes for the identification of quantitative trait loci (QTLs) involved in resistance to bacterial wilt. These TDFs may also allow for the identification and analysis of avirulence genes expressed by Xtg. The results of this study provide a valuable basis not only for a better understanding of the genetic control of resistance to bacterial wilt in Italian ryegrass, but primarily for the development of molecular tools to improve resistance breeding. [ABSTRACT FROM AUTHOR]

Resistance to the cyclohexanedione (CHD) herbicide sethoxydim was investigated in two UK Lolium multiflorum populations, Yorks A2 and PYL. Resistance screening experiments demonstrated a qualitative difference in the responses of the two populations to sethoxydim, suggesting that the molecular basis of resistance between them was different. After treatment, Yorks A2 plants were either alive (78% of sample tested) or dead (22% tested) but plants of the PYL population showed two further intermediate categories of response. The level of acetyl-CoA carboxylase (ACCase) insensitivity directly correlated with the degree of resistance at the whole plant level, indicating that the molecular basis of resistance is associated with differences in ACCase sensitivity in each population. Direct sequencing of the carboxyl transferase domain of the ACCase gene showed that an Ile-418-Leu substitution in the L. multiflorum chloroplastic ACCase (GenBank accession number ) confers resistance to sethoxydim in Yorks A2. This corresponds to amino acid residue 1781 in the Alopecurus myosuroides full ACCase sequence. This is the first report of this mutation in this L. multiflorum, which has also been reported in four other grass-weeds, including L. rigidum. However, no amino acid substitutions were found to be specifically associated with the resistant phenotypes in the PYL population and the molecular basis of resistance in this population remains to be resolved. [ABSTRACT FROM AUTHOR]

Genomic in situ hybridization (GISH) was used to characterize the chromosome constitutions of individual plants from a set of tetraploid and hexaploid cultivars of Festulolium developed and released in the Czech Republic from hybrids of Lolium multiflorum with Festuca pratensis and F. arundinacea. A simplified GISH protocol readily discriminated parental genomes in the hybrids and facilitated the screening of large numbers of plants per accession. The contribution of parental genomes in the cultivars tested ranged from predominance of chromatin from one of the parents to a more balanced contribution from both parents. However, in none of the cultivars were equal proportions of chromatin from both parents present. The parental contribution to the hybrids was both in the form of complete chromosomes or as chromosome translocations. In hexaploid cultivars from ( L. multiflorum × F. arundinacea) × F. arundinacea hybrids the average numbers of complete L. multiflorum chromosomes ranged from 4.95 to 7.5 and the numbers of translocations from 6.33 to 10.21. Two tetraploid cultivars from ( L. multiflorum × F. arundinacea) × L. multiflorum hybrids showed a strong prevalence of L. multiflorum chromatin and intergeneric translocations were rare. In the tetraploid cultivar ‘Perun’ of the L. multiflorum × F. pratensis hybrid there were 11.7 chromosomes of L. multiflorum and 14.7 recombined chromosomes on average. Reasons for the domination of one of the parental genomes in hybrid cultivars are not clear and are only partially explained by breeding history. Recombination rates of individual genomes in hybrids involving F. arundinacea were evaluated in double hybridization experiments. The results indicated a strong affinity of the L. multiflorum genome for the F. pratensis genome present in F. arundinacea and little affinity for the F. glaucescens genome. This suggests that introgressions from F. arundinacea into L. multiflorum are primarily limited to the F. pratensis genome which can be more readily accessed in L. multiflorum × F. pratensis hybrids. [ABSTRACT FROM AUTHOR]

The objective of this study was to clarify the effects of sulfate and phosphate at different sulfate concentrations, pH levels, and aluminum (Al) concentrations on aluminum phytotoxicity in ryegrass grown in mineral solution. The results demonstrated that, in general, both a high sulfate concentration and phosphate in the mineral solution had a positive effect on the detoxification of Al. Increased sulfate concentrations did not have a clear effect on the sulfur (S) or phosphorus (P) content within the shoot or root, because their uptake is regulated by Al uptake in the ryegrass, but a very good relationship was found between the P root content and Al root content ( r = 0.944**; p ≤ 0.01). The P and S root content and the aluminum:phosphorus molar ratio in roots were negatively correlated to shoot dry weight ( r = -0.747**, -0.619** and -0.816**, respectively; p ≤ 0.01), suggesting that Al tolerance is related to P nutrition. Relative root dry weight (RTI) measured at 90 d was a more sensitive indicator of Al toxicity than relative root or shoot length (RRL, RSL). This study showed that the most important Al detoxifying mechanisms in the ryegrass were apparently physiological Al-PO 4 precipitation inside the root and chemical AlSO 4 + complex formation in the nutritive solution. [ABSTRACT FROM AUTHOR]

The objective of the present work was to develop a method to distinguish between metabolically inactive and active parts of plant roots. White clover (Trifolium repensL.) roots were stained with 2,3,5-triphenyltetrazolium chloride (TTC) followed by root colour classification with an interactive scanner-based image analysis programme (WinRHIZO). Roots inactivated by boiling were unstained and pale brown, whereas fresh samples with predominantly metabolically active roots turned dark red, red or pale red after staining. A small amount of very young, presumable active roots (0.8% of total active root length) failed to stain red with TTC. The colour analysis of inactive and active roots was based on four colour classes for boiled roots and seven classes for fresh roots, respectively, as defined upon visual examination of images. Pixel colours falling outside the defined classes were allocated to the nearest defined class - an option that increased objectivity and stability and reduced the required number of colour classes. For the fresh white clover roots, 75-86% of the total root length was determined as active, while 3-7% of the boiled roots fell into the same category. The percentage of total root length measured by WinRHIZO that was identified as metabolically active was linearly correlated with the percentage of fresh roots in mixtures of fresh and boiled roots (R2=0.99). Colour classes chosenà priorifrom one experiment could be used to distinguish fairly satisfactorily between active and inactive roots of another white clover cultivar grown under other conditions, but failed to classify activity in ryegrass (Lolium multiflorumLam.) root samples. In the latter case, colour classes needed to be re-defined in order to produce reliable data. Our work shows that WinRHIZO’s colour identification sub-module provides a new promising tool to classify root activity as identified after staining with TTC, but colour classes must be carefully evaluated on every new occasion. [ABSTRACT FROM AUTHOR]

Ryegrass pollen (Lolium species) is a widespread source of air-borne allergens and is a major cause of hayfever and seasonal allergic asthma, which affect approximately 25% of the population in cool temperate climates. The main allergens of ryegrass pollen are the proteins Lol p 1 and Lol p 2. These proteins belong to two major classes of grass pollen allergens to which over 90% of pollen-allergic patients are sensitive. The functional rolein plantaof these pollen allergen proteins remains largely unknown. Here we describe the generation and analysis of transgenic plants with reduced levels of the main ryegrass pollen allergens, Lol p 1 and Lol p 2 in the most important worldwide cultivated ryegrass species,L. perenneandL. multiflorum. These transgenic plants will allow the study of the functional rolein plantaof these pollen proteins and the determination of potential for development of hypo-allergenic ryegrass cultivars. [ABSTRACT FROM AUTHOR]

Annual ryegrass (Lolium multiflorum Lam.) is an important crop grown on approximately 1.1 million hectares in the southeastern United States. Used primarily for winter grazing, ryegrass has considerable yield variation among production areas, possibly due to differences in ryegrass response to the range of soil properties encountered in Louisiana. The objectives of this research were: (i) to evaluate variation in soil nutrient status among a range of soil series; and (ii) to compare yield, mineral uptake, and livestock nutritional value of annual ryegrass grown on these soils. Two replicated greenhouse studies were conducted to evaluate two cultivars of annual ryegrass, Gulf and Rio, grown in seven distinct soils collected from throughout Louisiana. Soils were unamended and received no additional fertilizer during the studies. Each study was harvested twice for yield and nutrient uptake determinations. Plant tissue samples were analyzed for potassium (K), calcium (Ca), iron (Fe), magnesium (Mg), manganese (Mn), zinc (Zn), and copper (Cu) concentrations using atomic absorption spectrophotometry. There were no cultivar differences or cultivar by soil interactions for yield or nutrient uptake. Yield and nutrient uptake of K, Ca, and Mn, were affected by the soil used. None of the soils produced ryegrass with sufficient Ca to meet the requirements of a dairy cow (Bos taurus), even though several of the soils had adequate to high soil test levels of Ca. All of the soils produced ryegrass with adequate Mg for beef cows (B. taurus; Bos indicus), but only half provided adequate Mg for dairy cows. All soils produced forage that met the beef cow Zn requirement, but only six provided adequate Zn for dairy cattle. All soils produced ryegrass with enough Mn to meet the requirements of both beef and dairy cattle, but there were large variations among the forages grown on the seven soils. These results indicate that mineral supplementation for beef cattle fed ryegrass grown on these soils might not be essential, but mineral supplementation for dairy cattle would be necessary. #Approved for publication by the Director of the Louisiana Agricultural Experiment Station as manuscript no. 02‐09‐0176. [ABSTRACT FROM AUTHOR]

Abstract Annual ryegrass (Lolium multiflorum Lam.) is grown on more than one million ha in the south-eastern USA each year. Recommended and actual seeding rates vary substantially within the region. The objective of this study was to evaluate variation in seed weight, germination, seedling vigour and seasonal yield performance among annual ryegrass cultivars. During 1997, 1998 and 1999, seed from fourteen commercial cultivars was weighed and germinated to determine numbers of pure live seed (PLS) m-2 before yield evaluation at four locations. Seed from ten cultivars was planted at 0·7 and 2·0 cm depth in a greenhouse study to evaluate relative seedling vigour. Cultivar mean single-seed weight ranged from 2·4 to 4·8 mg in 1997, 1·8 to 4·5 mg in 1998, and 2·6 to 4·6 mg in 1999. Seed germination ranged from 78·8% to 98·0% in 1997, 82·3 to 98·3% in 1998 and 77·8 to 98·3% in 1999. Seed number, PLS m-2 , ranged from 675 to 1289 in 1997, 710 to 1550 in 1998, and 717 to 1179 in 1999. Among the ten cultivars evaluated for seedling vigour, seedling weight differed between planting depths and a significant cultivar by year interaction was observed. Seedling weight was highly correlated with seed weight at each seeding depth. The effect of increasing number of PLS m-2 on subsequent yield performance, although small, was consistently negative. These results indicate that target plant populations may be obtained more economically by adjusting seeding rates for seed size differences among cultivars and seed lots of annual ryegrass. [ABSTRACT FROM AUTHOR]

Summary • In this study, we tested the hypothesis that environmentally induced changes in the oxygen isotope ratio of leaf water are recorded in grass blade cellulose during leaf-blade expansion. • Grasses were grown hydroponically in chambers that allowed for control of relative humidity while keeping isotopic inputs (namely source water) constant. • In experiments where relative humidity was changed from 35% to 93% during grass blade expansion, a 10‰ shift in cellulose δ 18 O was observed along single grass blades of Lolium multiflorum . However, statistically significant changes were not detectable with relative humidity of 93% to 70%. • It is shown that grass blades, analogously to tree rings, record environmental change on an interseasonal basis. In light of this, care must be taken to compare leaves of the same developmental stage to avoid confusion of environmental effects with physiological effects in interpretations of leaf organic material δ 18 O. The results presented here confirm the ability of the current empirical models to predict the oxygen isotope ratio of cellulose in both grass blades that expanded in constant and variable growth conditions. [ABSTRACT FROM AUTHOR]

The imminent decline in species diversity coupled with increasing exotic species introductions has provoked investigation into the role of resident diversity in community resistance to exotic species colonization. Here we present the results of a field study using an experimental method in which diversity was altered by removal of less abundant species and the resulting disturbance was controlled for by removal of an equivalent amount of biomass of the most common species from paired plots. Following these manipulations, the exotic grass, Lolium temulentum, was introduced. We found that exotic species establishment was higher in plots in which diversity was successfully reduced by removal treatments and was inversely related to imposed species richness. These results demonstrate that less common species can significantly influence invasion events and highlight the potential role of less common species in the maintenance of ecosystem function. [ABSTRACT FROM AUTHOR]

Diclofop-methyl resistance was evaluated in populations of Italian ryegrass (Lolium multiflorum Lam.) infected and uninfected with fungal endophyte (Neotyphodium). Survival was tested in susceptible populations using herbicide screening. The results served as inputs to a model for investigating the role of endophyte infection in the evolution of L. multiflorum resistance to herbicide. The tolerance of infected plants varied depending on the origin of the population and the herbicide dose. Only in some populations and at some diclofop-methyl doses did plants infected with these endophytes have higher survivorship than endophyte-free plants. The model demonstrated that endophytes might indeed play an important role in the evolution of herbicide-resistant weeds, delaying the appearance of herbicide resistance. [ABSTRACT FROM AUTHOR]

Symptoms of Meloidogyne naasi invasion, development and reproduction were compared on 17 cloned ryegrass (Lolium multiflorum and L. perenne) plants, previously classified as susceptible (5 clones) or resistant (12) to a Welsh population. Observations on galling and reproduction confirmed the classification of most clones but some intermediate host status phenotypes were distinguished. Smaller root size at and immediately after inoculation was related to the generally poorer host status of L. perenne clones compared with those of L. multiflorum. Root axes number or size was not related to resistance and susceptiblity in either ryegrass species. In ryegrasses, resistance was expressed by slower nematode development rates, fewer females matured and those that laid eggs were less fecund. Gall numbers at 36 days after inoculation reliably predicted host status. A poor host cultivar of Phleum pratense included some plants on which a few galls with fully fecund females developed. The selected ryegrass clones maintained their phenotype when tested with populations of M. naasi from Belgium and France. Nonetheless, it cannot be concluded from these experiments that there is no heterogeneity for virulence in these nematode populations. Resistance du ray-grass, Lolium spp., a trois populations europeennes du nematode a galle Meloidogyne naasi - Les symptomes causes par la penetration, le developpement et la reproduction de Meloidogyne naasi ont ete compares chez 17 clones de ray-grass (Lolium multiflorum et L. perenne) dont 5 consideres auparavant comme sensibles et 12 comme resistants a une population provenant du Pays de Galles. Les observations relatives a la formation des galles et a la reproduction confirment la qualification de la plupart de ces clones mais quelques phenotypes a statut d'hote intermediaire ont ete detectes. Une longueur de racines plus faible au moment de et immediatement apres l'inoculation est en general correlee au statut d'hote mediocre des clones de L. perenne si on les compare a ceux de L. multiflorum. Le nombre et la taille des racines axiales ne sont correles ni a la resistance ni a la sensibilite chez aucune des especes de ray-grass. La resistance s'exprime chez le ray-grass par le taux plus faible du developpement du nematode, le moindre nombre de femelles matures et une fecondite moins elevee chez celles qui pondent des oeufs. Le nombre de galles releve 36 jours apres l'inoculation permet de predire le statut d'hote de facon fiable. Un cultivar de Phleum pratense a statut d'hote mediocre comportait cependant quelques plants presentant un petit nombre de galles contenant des femelles parfaitement fecondes. Les clones de ray-grass etudies ont conserve leur phenotype lors de tests envers des populations de M. naasi provenant de France et de Belgique. Ces experiences ne permettent cependant pas de conclure qu'il n'existe aucune heterogeneite dans la virulence de ces populations de nematode. [ABSTRACT FROM AUTHOR]

Net rates of NO3- and K+ uptake were compared for oilseed rape (Brassica napus L. cv. Jet neuf), perennial ryegrass (Lolium perenne L. cv. S23), Italian ryegrass (Lolium multiflorum Lam. cv. Augusta) and wheat (Triticum aessivum L. cv. Fenman) in flowing solution culture during a 4-day sequence of low-low-high-high natural irradiance. Concentrations of NO3- (10 μM) and K+ (2.5 μM4 mmol NO3 m-2 h-1 and >1.4 mmol K+ m-2h-2. These higher rates were maintained throughout the following night. The lag-time between maximum irradiance and the onset of the highest acceleration in uptake was greater for NO3 (5-8 h) than for K+ (≤ 1h) in rape, wheat and Italian ryegrass. Uptake of NO3 by perennial ryegrass showed an almost constant acceleration for 18 h following maximum irradiance. In all species the measured maximum inflows (uptake rate per unit root length) of both ions were greater than theoretical maximum potential inflows to a non-competing infinite-sink root in soil, by factors of 7 and 36, respectively, for NO3- and K+, averaged over all species.

In Lolium multiflorum nodal segments, bending responses both to geostimulation and unilateral indole-3-acetic acid (IAA) application exhibited much variability in their lag times and speeds of early bending. Despite this variability, mean response curves to gravity and auxin stimulus were markedly similar with each having a phase of immediate, negative bending followed by phases of slow, positive bending and eventually more rapid, positive bending within 40 min of initial treatment. Comparison of lag times for response to geostimulation and unilateral IAA application, whether derived from the mean of individual replicates, or from mean curve data, showed that at least 4 min is available in this geotropic system for establishment of asymmetric auxin levels that could lead to differential growth. The hypothesis that variability in georesponse in Lolium nodal segments is linked to variable sensitivity of geosensitive tissue to auxin was tested using matching longitudinally-halved nodal segments and evidence was obtained in support of the hypothesis from lag time but not from early bending speed data. The implications of the findings for an involvement of endogenous IAA in shoot geotropism together with the necessity to understand better the complex behaviour of bending response in individual replicates are discussed. [ABSTRACT FROM AUTHOR]