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Perennial ryegrass (Lolium perenne L.) is one of the most widely used species for sports fields in temperate climates because of its high wear tolerance. However, wear tolerance of cultivars may vary according to local environmental conditions and turfgrass management. In this study, we evaluated the wear tolerance of six perennial ryegrass cultivars (Adagio, Apple SGL, Equate, Firebird, Principal 2, Tetradark) under two fertility treatments (100 or 200 kg N-ha21-yr21) over 2 years. The field trial was performed at the Experimental Agricultural Farm at the University of Padova in northeastern Italy in a silty loam soil. Plots were arranged in a randomized complete block with three replications and subjected to three traffic events per week using a sports field wear simulator. Turfgrass quality (TQ), percent green cover (PGC), and normalized difference vegetation index (NDVI) were recorded every 2 weeks and averaged over each month. Although perennial ryegrass cultivars responded differently to wear stress, the higher nitrogen (N) rate positively affected the TQ of them all. 'Tetradrak' and 'Equate' had the lowest TQ, especially during the active growing seasons (spring and autumn). However, 'Tetradark' was particularly negatively affected during the cool fall months. The impact of a higher N fertilization rate on PGC and NDVI appeared to be more pronounced in spring than in fall. Furthermore, slight differences among cultivars and treatments were observed in summer and winter when temperatures were a limiting growth factor. [ABSTRACT FROM AUTHOR]

In transition areas, cool season turfgrasses are overseeded in autumn to maintain the high quality of dormant warm season turfgrasses, while in spring several agronomic methods (scalping, coring, topdressing, verticutting, irrigation, and targeted fertilization) or chemical desiccation are adopted to remove the cool season turfgrasses from the stand. To reduce chemical applications, several methods of "thermal weeding" have been experimented with, but little is known about these methods in zoysiagrass (Zoysia spp. Willd) spring transition. A study was conducted at the University of Pisa, Italy, on Manila grass (Zoysia matrella (L.) Merr., cv "Diamond") (Zm) overseeded with perennial ryegrass (Lolium perenne L.) (Lp) with the aim of comparing different methods of cool season grass suppression (scalping and hot foam) and different application rates of nitrogen. To assess treatment effect, green cover, turf quality, turf color, shoot density, and some vegetation indices (GLI, DGCI and NDVI) were determined. An average green cover of at least 90% was obtained on all plots seven weeks after the treatments. While scalping had minor effects on turf appearance and on polystand composition, hot foam had a stronger effect on turf color, green cover, and turf quality in the weeks following application. Once it had recovered from the hot foam treatments, the turf had a greater number of Zm shoots and a relevant reduction of Lp shoots. The hot foam was very effective in suppressing Lp while maintaining Zm recovery capacity. [ABSTRACT FROM AUTHOR]

In Europe, glyphosate-resistant weeds have so far only been reported in perennial crops. Following farmers' complaints of poor herbicide efficacy, resistance to glyphosate as well as to ACCase and ALS inhibitors was investigated in 11 populations of Lolium spp. collected from annual arable cropping systems in central Italy. Field histories highlighted that farmers had relied heavily on glyphosate, often at low rates, as well as in a non-registered crop. The research aimed at elucidating the resistance status, including multiple resistance, of Lolium spp. populations through glasshouse screenings and an outdoor dose-response experiment. Target-site resistance mechanism was also investigated for the substitutions already reported for EPSPs, ALS and ACCase genes. Three different resistant patterns were identified: glyphosate resistant only, multiple resistant to glyphosate and ACCase inhibitors and multiple resistant to glyphosate and ALS inhibitors. Amino acid substitutions were found at position 106 of the EPSPs gene, at position 1781, 2088 and 2096 of the ACCase gene and at position 197 and 574 of the ALS gene. Not all populations displayed amino acid substitutions, suggesting the presence of non-target-site-mediated resistance mechanisms. After 39 years of commercial availability of glyphosate, this is the first report of multiple resistance involving glyphosate selected in annual arable crops in Europe. Management implications and options are discussed. [ABSTRACT FROM AUTHOR]

Aims A fungal endophyte, Neotyphodium uncinatum, accumulates N-formylloline, which is toxic to Hemipteran insects, in Italian ryegrass. This study aimed to clarify the dynamics of N. uncinatum and N-formylloline in Italian ryegrass, and their relationship to insect resistance. Methods and Results Changes in the density and localization of N. uncinatum and N-formylloline in N. uncinatum-infected Italian ryegrass were examined by real-time PCR and gas chromatography, respectively. Neotyphodium uncinatum multiplied on pseudostems at the flowering stage, and then increased on inflorescences at the ripening stage. On the other hand, N-formylloline accumulated heavily in inflorescences and leaf blades, but lightly in pseudostems at the ripening stage. In field experiments, N. uncinatum-infected Italian ryegrass suppressed the occurrence of Stenotus rubrovittatus, which fed on the inflorescences, but was not effective to Laodelphax striatellus, which do not necessarily prefer a particular plant tissue. Conclusion Localization of N. uncinatum and N-formylloline were discordant in Italian ryegrass. The N. uncinatum-infected Italian ryegrass was effective to only insects that prefer to feed on particular plant tissues containing N-formylloline. Significance and Impact of Study Our data implies that the relationship between insect habits and the dynamics of alkaloids in plants is important for the effective use of endophyte-infected crops. [ABSTRACT FROM AUTHOR]

Highlights: [•] We evaluated the effect of management practices on establishment of Italian ryegrass. [•] We tested pasture's ability to re-establish following a year without seed production. [•] Grazing intensity is the first factor affecting subsequent pasture establishment. [•] Pasture establishment by self-seeding relies on the annual seed replacement. [•] Grazing must be managed to allow sufficient reproductive tiller production. [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]

Determines the changes of seedling root fluorescence expression in perennial ryegrass in Italy. Characteristics of ryegrass cultivar genetic purity; Identification of the fluorescence levels of cultivars; Detection of physical and genetic contamination of ryegrass.

A comprehensive research project was set up to characterize by different approaches some Italian populations of Lolium spp. susceptible and resistant to diclofopmethyl. The present study was aimed at the taxonomic identification of these Lolium populations on the basis of the electrophoretic analysis of seed reserve proteins. Electrophoresis confirmed the great range of variation detected by preliminary morphological analysis. Approximately half the individuals in each population could be classified as belonging to Lolium multiflorum or Lolium rigidum, the most common Lolium species present in the area. However, electrophoretic patterns revealed a significant number (40-60%) of hybrid individuals in all populations. The origin of these off-types was postulated as resulting from both intrageneric hybridization among different Lolium species and intergeneric hybridization between Lolium and Festuca genera. No significant differences were detected in the taxonomy of herbicide-susceptible and -resistant populations. [ABSTRACT FROM AUTHOR]

The mechanisms of herbicide resistance were investigated in two diclofop-methyl-resistant Lolium spp. populations from central Italy, Roma ’94 and Tuscania ’97. These two populations were compared with two susceptible Italian populations (Vetralla ’94, Tarquinia ’97) and a resistant and a susceptible population from Australia, SLR31 and VLR1. The activity of acetyl Co-A carboxylase (ACCase) extracted from susceptible (S) or resistant (R) individuals from the Italian populations was inhibited by both aryloxyphenoxypropanoate (diclofop acid and fluazifop acid) and cyclohexanedione (sethoxydim) herbicides. Diclofop-methyl was rapidly de-esterified to diclofop acid at a similar rate in both R and S populations. In all populations, diclofop acid was subsequently degraded to other metabolites. The rate of degradation of diclofop acid was not significantly faster in R than in S populations; however, diclofop acid was degraded more completely in Roma ’94 and Tuscania ’97 compared with the S populations. Application of the mixed-function oxidase inhibitor 1-aminobenzotriazole (ABT) significantly enhanced diclofop-methyl toxicity towards both R populations, but not in S populations. However, enhanced herbicide metabolism does not completely account for the measured resistance level. A mechanism other than an altered ACCase and enhanced herbicide metabolism appears to be responsible for resistance to diclofop-methyl in Roma ’94 and Tuscania ’97. [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]

Populations of Lolium spp. collected in central Italy were screened for resistance to acetyl-coenzyme A carboxylase (ACCase)-inhibiting herbicides and compared with known susceptible and resistant Lolium rigidum (Gaud.) populations from Australia. Populations Roma’94 and Tuscania’97 were up to 8- and 7.5-fold more resistant to diclofop-methyl, respectively, than susceptible populations in pot experiments. However, populations Tarquinia’97 and Vetralla’94 were not resistant. Diclofop-methyl resistance levels in the Italian populations were lower than in the Australian populations SLR31 and WLR96 (16.5 and > 64 times more resistant than S respectively). In an agar germination test, Tuscania’97 showed low levels of cross-resistance to fluazifop-p-butyl, whereas no cross-resistance was found in the Roma’94 population. [ABSTRACT FROM AUTHOR]

Remote sensing-based evapotranspiration (ET) models with various levels of sophistication have emerged recently with the possibilities of user-defined model calibrations. Their application for water resources management and climate studies from regional to global scale has been rapidly increasing, which makes it important to validate field scale ET in a complex crop assemblage before operational use. Based on in situ flux-tower measurements by the eddy-covariance (EC) system, this study tested three single-source energy balance models for estimating daily ET from fennel/maize/ryegrass-clover cropland rotations in a Mediterranean context in southern Italy. The sensitivity of three user-friendly ET models (SEBS, QWaterModel, and METRIC-EEFlux) with reference to the EC system over a center pivot irrigated cropland is discussed in detail. Results in terms of statistical indicators revealed that SEBS and METRIC-EEFlux showed reasonable agreements with measured ET (r2 = 0.59SEBS, RMSE = 0.71 mm day−1; r2 = 0.65METRIC, RMSE = 1.13 mm day−1) in terms of trends and magnitudes. At 30 m spatial resolution, both models were able to capture the in-field variations only during the maize development stage. The presence of spurious scan lines due to sensor defects in Landsat L7 ETM+ can contribute to the qualities of the METRIC-Efflux's ET product. In our observation, the QWaterModel did not perform well and showed the weakest congruency (r2 = 0.08QWaterModel) with ground-based ET estimates. In a nutshell, the study evaluated these automated remote sensing-based ET estimations and suggested improvements in the context of a generic approach used in their underlying algorithm for robust ET retrievals in rotational cropland ecosystems. [ABSTRACT FROM AUTHOR]

On two occasions in 1995 the effects of severity of conditioning and pressing on the drying rate of Italian (Lolium multiflorum Lam.; IR) and perennial (Lolium perenne L.; PR) ryegrass were assessed. The cut herbage was either left unconditioned (0C) or conditioned by passing through a laboratory scale macerator three (3C) or six (6C) times after which the herbage was placed into wire mesh trays and either left unpressed (0P) or pressed (P). The twelve treatment combinations (two species × three conditioning levels × two pressings) were replicated three times on each of the two occasions. On each occasion the trays plus herbage were weighed at hourly intervals over an ≈6-h period and dry matter (DM) of the herbage was estimated from the weight change. Pressing treatment gave, on average, a negative effect on the drying rate of the herbage. Conditioning significantly (P < 0·001) increased the drying rate of the herbage. Compared with 0C herbage, the greatest increase in drying rate was obtained with the 3C treatment; the additional conditioning imposed by the 6C treatment produced only a small further increase in drying rate. Drying constants calculated for each treatment combination showed that IR dried 1·45 times faster than PR and that, compared with 0C, herbage drying rate was 2·18 and 2·38 times greater as a consequence of the 3C and 6C treatments respectively. Pressed (P) herbage dried at a rate of 0·90 of that of the unpressed herbage (0P). [ABSTRACT FROM AUTHOR]

In the Mediterranean environment, root systems are very important for water utilization. For this reason, the effects of selection for increased root dimensions upon root and shoot characteristics of a natural population of Lolium rigidum Gaud. were analysed. Two cycles of phenotypic recurrent selection were carried out on a population collected in Nurra (north-western Sardinia, Italy). Plants derived after two cycles of selection, together with unselected plants, were grown hydroponically in a greenhouse. Data on root volume, longest root length, number of stems and leaves, leaf length, shoot and root dry weight were collected from the selected material and also from unselected material for use as a control. An analysis of variance was performed and correlation coefficients were calculated. The increased size of the root system did not have a negative effect on the above-ground biomass and there was genetic variation for root traits in the 'Nurra' population. The improved population will be utilized for further breeding work to obtain L. rigidum varieties capable of withstanding dry periods during the vegetative phase. [ABSTRACT FROM AUTHOR]

Measures the dark respiration rates of roots and aerial parts of ryegrass and barley in Italy. Root respiration in cropped versus bare soil; Air temperature and respiration rate; Influence of soil water on respiration; Variations in respiration rate of barley.

Abstract The relationship between rate of water loss of Italian ryegrass (Lolium multiflorum ) and crop properties, weather conditions and mechanical treatments were studied on a field scale, as was the importance of the variables and their combined effects on influencing the wilting process. Eleven forage-drying experiments were performed between 1992 and 1994 on diploid and tetraploid cultivars cut at different growth stages, ranging from early elongation to flowering, under environmentally variable conditions. The rate of drying was measured until a moisture content of 1 g water g-1 dry matter (DM) (500 g kg-1 ) was reached, or for a maximum of 2 days by calculating the rate of water loss from two consecutive hourly weights of swath portions placed on trays. Multiple regression analysis was used to correlate the drying rate (k ) with crop properties and with meteorological and mechanical treatment variables. The interaction between potential evapotranspiration (ET0 ) and the moisture content of grass at cutting (M grass appeared to be the most important variable, from the twenty-one tested, in influencing K. This variable shows that the same quantity of energy available for evaportaion acts in different ways when the water content of the crop at cutting differs. The rate of water loss is also influenced by the M grass itself, surgacae density of the swath, tedding and the weather conditions on the first day of drying. The value of M grass at cutting is greatly greatly dependent on crop maturity and ploidy. The tetraploid cultivars, with a higher inital moisture content, lost water more slowly than diploid cultivars did. Because the date of cutting cannot be delayed, owing to the decline in nutrive value, it is helpful to select for cultivars with low moisture contents at cutting, as well as applying mechanical treatment (spreading and tedding), in order to keep the wilting period as short as... [ABSTRACT FROM AUTHOR]

The results of a four-year investigation carried out in Central Italy on the occurrence of perennial ryegrass rusts from 1989-92 are reported. The crown rust (Puccinia coronata) was the most frequently recorded in the surveyed are while P. graminis was only occasionally detected. The causal agents were identified by the morphological criteria proposed by CUMMINS (1971). A single-pustule isolate of P. coronata was used to test the resistance of seven ryegrass cultivars under greenhouse conditions. Two cultivars, 'Artal' and 'Score', proved resistant to the fungus isolate while the remaining ('Elka', 'Patora', 'Pleno', 'Sisu' and 'Vejo') were high susceptible. [ABSTRACT FROM AUTHOR]

This article shows the resistance of a population of ryegrass (Lolium multiflora) to crown rust in a resistance breeding program in Italy. This pathogen was attacked by a rust during the spring and autumn and was identified as Puccinia recondita. When plants were grown in a glasshouse, the pustules became darker in color due tot e accumulation of orange-brown uredospores. Both natural and synthetic ryegrass populations varied markedly in their resistance to P. condita when scored for susceptibility on a 1-5 scale which is considered significance for resistance breeding.