Varieties Of Lolium Perenne Research Articles

Delayed chlorophyll a fluorescence, MR 820, and gas exchange changes in perennial ryegrass under salt stress

Perennial ryegrass (Lolium perenne L.) is one of the more popular grass species in Europe. It is commonly used for starting lawns in urban areas, where plant growth is limited by many environmental conditions. The contamination of soils by salt is one of the major problems in urban green areas, as well as in natural areas. The basic aim of this study is to provide a detailed in vivo analysis of the changes in the delayed chlorophyll fluorescence and MR 820 signals (induced by salt stress) of two lawn varieties of perennial ryegrass, and to find out if there are correlations between these parameters and gas exchange. Two lawn varieties of Lolium perenne L. were used: Nira and Roadrunner. Salinization was performed at 8 weeks after sowing by adding NaCl in water solution (0, 0.15, and 0.30M). There were 8 terms of measurement: 0h, 24h, 48h, 96h, 144h, 192h, 240h, and 288h after salinization. Our results showed that delayed fluorescence is a tool that can bring completely new opportunities for detecting stress in plants caused by salt. Our work allowed us to identify various limitation patterns in the photosynthetic efficiency of perennial ryegrass lawn varieties grown under salt stress conditions. Significant differences between the two tested varieties in response to salt stress were confirmed.

Bio-refining of perennial ryegrass (Lolium perenne): evaluation of aqueous extracts for plant defence elicitor activity using French bean cell suspension cultures

There is growing interest in the bio-refining of foliage grasses to yield a range of industrial raw products. The aim of this research was to evaluate if aqueous extracts from grasses have the potential to act as crop bio-stimulants by assessing their defence elicitor activity. Field-grown foliage (500 g fresh weight) from the Lolium perenne varieties Tyrella, Dromara, Abermagic, and Spelga were homogenised in water (2 l) and the run-off liquid filtered through Whatman No. 1 filter paper before freezing. Thawed filtrate was centrifuged at 21,000 rpm for 15 min, to give pellet and supernatant fractions, which were assayed separately for defence elicitor activity by adding them to cell suspension cultures of Phaseolus vulgaris in the early exponential phase of growth (7–10 days into a 14 days culture passage). Elicitor activity was evaluated 24 h after treatment by assessing the extent of necrosis (browning) in the P. vulgaris cells. Supernatant and pellet fractions of all four L. perenne varieties were found to have potent cell defence elicitor activity, although there were relatively small but significant differences between the varieties. In a second series of extractions, homogenisation of tissues in water was compared with screw-pressed juice using the varieties, Malone, Seagoe, and Copeland. Varietal differences in elicitor activity of these extracts were removed if they were first equalised for protein content prior to eliciting the bean cells, although the screw-pressed juice was marginally more active as an elicitor than the homogenised extract. Autoclaving the extracts in attempts to solubilise/release additional elicitor compounds neither increased nor decreased the elicitor activities of the supernatant or pellet fractions. Elicitor activity of the extract was partially reduced by treating with a cation exchange resin, almost entirely removed by adsorption onto activated carbon and completely abolished by ashing at 650 °C. The L. perenne defence elicitor(s) is therefore organic rather than inorganic, heat-stable, cationic at neutral pH, and readily soluble in water at room temperature.

Characterization of native perennial ryegrasses for persistence in mediterranean rainfed conditions

Forage varieties of Lolium perenne L. (perennial ryegrass) available on the seed market generally show low persistence in rainfed Mediterranean conditions. Eleven native populations of perennial ryegrass from Corsica and Sardinia, previously chosen for their ability to re-grow after summer drought, were grown in a 3-year field experiment in Sardinia (Italy). The objective was to characterize these populations for traits linked with persistence in rainfed conditions under low input management. Their differentiation and stability over time were assessed for some morphological traits (tiller, spike and flag leaf length, number of spikelets spike-1, spikelet and glume length). In addition, some agronomic traits (canopy height, dry matter and seed yield, spike emergence date) and physiological traits (canopy temperature and leaf area index) were observed to identify, using a multivariate approach, correlations with persistence. A significant variability between accessions was observed for all the morphological traits over the three years of observation; a significant Accession × Year interaction was found for tiller length, flag leaf length and number of spikelet/spike with a plastic adaptation to weather conditions of some populations, these traits being the most important contributors to persistence. The most persistent perennial ryegrass accession proved to be the most vigorous and early flowering one. Some contrasting accessions represent valuable resources to be exploited into breeding programs based on Mediterranean germplasm, in order to provide farmers with perennial ryegrass varieties adapted for different purposes and which are able to survive to more frequent hot and dry summer conditions in a context of climate change.

The Effect of Seed Health of Perennial Ryegrass (Lolium Perenne L.) on Germination Capacity

Abstract The analysis of seed health and germination capacity of 7 varieties of Lolium perenne, originated from two breeding station and two seed company localized in different places of Poland, harvested in 2006, 2007 and 2008 were performed. Results of mentioned analysis indicated that seeds were contaminated by numerous species of fungi. The most numerous group of fungi were saprophytes or weak parasites such as: Alternaria alternata, Epicoccum nigrum, Septonema chaetospira and Penicillium spp. Pathogenic species were represented by species of Drechslera, Fusarium, Phoma, Curvularia lunata and Bipolaris sorokiniana. Seed germination capacity was influenced by contamination of fungi. It was found that seed more often contaminated by fungi germinated much poorer then seed with lower infection.

Genetic differences in root mass of Lolium perenne varieties under field conditions

Although grasses have dense rooting systems, nutrient uptake and productivity can be increased, and N-leaching reduced, if rooting is further improved. The variation in root mass of 16 varieties of Lolium perenne was studied under field conditions in two experiments on sandy soil in The Netherlands. The chosen varieties differed in genetic and aboveground characteristics such as ploidy, productivity and grass cover. Root dry matter (RDM) was measured in the 0–8, 8–16 and 16–24 cm soil layers. In summary, we found that RDM of perennial ryegrass differed significantly between varieties under field conditions. These differences were not linked to grass yield, which indicates that it is possible to select perennial ryegrass varieties that combine high aboveground productivity with high RDM. In the first experiment, which was managed by cutting, diploid varieties had higher RDM than tetraploid varieties. Grand mean RDM in the second experiment, which was managed by cutting as well as grazing, was lower than in the first experiment. In this experiment, total RDM was not influenced by ploidy but by grass cover type: high grass cover types had higher RDM. Differences in management between the two experiments possibly explain the differences in RDM and in the influence of chosen characteristics on RDM. Considering challenges in the areas of climate change, water availability, pollution and soil degradation, grass varieties with improved root systems could significantly contribute to a more efficient use of nutrients and water, erosion control, soil improvement and carbon sequestration.

Low temperature and hardening effects on photosynthetic apparatus efficiency and survival of forage grass varieties

Freezing tolerance is essential for perennial plants and ability to adapt to extreme temperature is crucial for their survival in many environments. Freezing tolerance of hardened and unhardened plants of Dactylis glomerata and Lolium perenne varieties was probed by their quantum photosynthetic efficiency using the chlorophyll fluorescence technique. Quantum yield of photosystem II (PSII) electron transport (Φ<sub>PSII</sub>), maximal (F<sub>m</sub>’) and steady-state (F<sub>s</sub>) chlorophyll fluorescence yields of light-adapted samples were measured. Φ<sub>PSII</sub> depended on developmental phase, temperature and hardening process. A clear decline in PSII activity, especially after –10°C application was observed. Plant hardening during emergence phase had a positive impact on PSII activity, especially after –5°C application. After 72 h of –5°C temperature treatment, hardened plants showed quicker recovery of their photosynthetic apparatus (0.527–0.697) as compared to unhardened ones (0.224–0.330). Stress temperature of –10°C caused irreversible changes of photosynthetic apparatus of hardened and unhardened plants independently of growth phases (0.003–0.014). Φ<sub>PSII</sub> and F<sub>m</sub>’ parameters were strongly correlated with shoots survival under stress. Our results suggest that perennial plants’ hardening allows them to survive low temperatures due inter alia enhancing their photosynthetic machinery performance.

Production potential of some varieties of Lolium perenne in pasture and meadow regime

Production potential of some varieties of Lolium perenne in pasture and meadow regime

Impact of defoliation frequency on regrowth and carbohydrate metabolism in contrasting varieties of Lolium perenne.

The aims of the study were to gain a better understanding of fructan metabolism regulation during regrowth of Lolium perenne, and to evaluate the role of fructans of remaining tissues as well as carbon assimilation of new leaf tissues in refoliation. Two varieties that contrast for carbohydrate metabolism, Aurora and Perma, were subject to severe and frequent or infrequent defoliations before regrowth. Aurora, which had a greater content of fructans in leaf sheaths than Perma before defoliation, produced more leaf biomass within the 4 days following the first cut. At the end of the regrowth period, Aurora produced more leaf biomass than Perma. Photosynthetic parameters, which were barely affected by defoliation frequency, could not explain these differences. Fructan synthesising activities [sucrose:sucrose 1-fructosyltransferase (1-SST) and fructan:fructan 6G-fructosyltransferase (6G-FFT)], declined after defoliation. In elongating leaf bases, corresponding transcript levels did not decline concomitantly, suggesting a post-transcriptional regulation of expression, while in leaf sheaths the gene expression pattern mostly followed the time-course of the enzyme activities. Regulation of Lp1-SST and Lp6G-FFT gene expression depends, therefore, on the sink-source status of the tissue after defoliation. During the phase of reserve accumulation, fructosyltransferase activities together with corresponding transcripts increased more in frequently defoliated plants than in infrequently defoliated plants.

Zawartość azotu i podstawowych składników mineralnych w runi pastwiskowej w różnych latach jej użytkowania

The aim of this paper was a comparison of the content of nitrogen and basic mineral components (P, K, Ca and Mg) in pasture sward in dependence on the period of utilization. The studies were carried out in 1996–2004 in a pasture experiment on peat-muck soil. Changes of the content of nutrients in the pasture sward were introduced in the first and third regrowth in two periods of utilization (years 1998–1999 and 2003–2004). Mixtures with different varieties of Lolium perenne were involved in research (Polish – ‘Anna’, ‘Arka’, ‘Maja’, ‘Rela’, ‘Solen’ and SZD-291 strain as well as Dutch – ‘Baristra’, ‘Barezane’ and ‘Barlano’). To estimate the chemical composition of fodder a sward of control mixture was chosen (without Lolium perenne) and mixtures with selected varieties of this species (‘Anna’, Maja’, ‘Solen’, ‘Baristra’, ‘Barezane’ and ‘Barlano’). The research stated appreciable differentiation of the most of studied components in dependence on regrowth as well as period of utilization. The content of nutrients was higher in the sward of third regrowth (except phosphorus), as well in the first and the second periods of utilization. Pasture fodder was characterized by a much by higher content of nitrogen in the second period of utilization (years 2003–2004). There was also found a higher content of potassium and calcium. However, the content of magnesium and phosphorus was not clearly diverse in dependence on the period of utilization. The content of the studied components oscillated in the range of optimum or higher values (mainly nitrogen in the second period of utilization).

Carbon assimilation and partitioning into non-structural carbohydrate in contrasting varieties of Lolium perenne

Rates of photosynthetic carbon assimilation and the partitioning of carbon into different sugar fractions have been compared in Aurora and Perma, two varieties of perennial ryegrass (Lolium perenne L.). Perma had a higher photosynthetic rate than Aurora at all irradiances, and numerically a considerably higher apparent maximum quantum yield although this was not statistically significant. On a leaf area basis Perma had heavier leaves that contained more chlorophyll a, chlorophyll b and carotenoid. Carbohydrate was predominantly present in the leaves of both varieties as sucrose and fructan. Fructose, glucose and starch were undetectable or only present in trace amounts. Perma leaf blades and sheaths contained more sucrose and more small (DP3) fructan than Aurora, but less polymeric fructan. Following depletion of carbohydrate pools in low light, excised leaves were induced to accumulate fructan at high light. Perma accumulated 88 % more water-soluble carbohydrate and 90 % more starch than Aurora. However after 24 h the polymeric fructan content of Perma leaves was still lower than that of Aurora. The increase in carbohydrate content of Aurora leaves was nearly all explained by the increase in polymeric fructan, whereas Perma partitioned less into polymeric fructan and contained significantly more glucose, sucrose and DP3 fructan. Additionally, the average chain length of Perma polymeric fructan was shorter than that of Aurora.

Exotic Lolium perenne Varieties: Their Forage Value and Soil Cover Potential in Himalayas Region

Exotic Lolium perenne Varieties: Their Forage Value and Soil Cover Potential in Himalayas Region

Comparison of growth and carbohydrate accumulation in seedlings of two varieties of Lolium perenne

Following the identification of suitable traits, the genetic basis of physiological processes such as growth and carbohydrate accumulation can be examined with QTL analysis. Seedling growth was studied in two varieties of perennial ryegrass ( Lolium perenne L.) at two stages (following germination and after defoliation) during transitions from reserve-driven growth to current-photosynthate-driven growth. Total water-soluble carbohydrate contents of leaf blades, sheaths and roots were also measured. Aurora (a high-sugar variety) was capable of rapid growth, and grew faster than Perma when growth was reserve-driven. Perma had a low reserve carbohydrate content and grew slowly when growth was reserve-driven. When growth was fuelled by current photosynthate, Perma grew faster than Aurora and replaced its carbohydrate reserves more rapidly. Changes in growth rate appeared to precede changes in water-soluble carbohydrate content. It is concluded that the extent of water-soluble carbohydrate accumulation was inversely related to constitutive growth rate, and that neither process appeared to be limited by photosynthate supply. Traits amenable to QTL analysis are identified.

Primary and Secondary Induction Requirements for Flowering of Contrasting European Varieties of Lolium perenne

The flowering requirements of six European varieties of Lolium perenne L. were studied in controlled environments. In experiments on primary induction, flowering was recorded after transfer to long days (LD) in a greenhouse at 12–24°C. In experiments on secondary induction, primary induction was first accomplished at 6°C/10h daylength for 12 weeks. When evaluated by the 50% heading criterion, the requirement for duration of primary induction at 6°C/8h daylength was <3 weeks in Mediterranean, 5–6 weeks in Central European and 7–8 weeks in Scandinavian varieties. While ‘Veyo’ (Italy) flowered profusely regardless of temperature or daylength during primary induction, critical temperatures for primary induction in SD and LD were 15 and 11°C in ‘Baca’ (Czech Republic) and 11 and 7°C in ‘Falster’ (Denmark). The critical photoperiod for secondary induction at 15°C ranged from 12h in ‘Veyo’ and 14h in ‘Baca’ to 16.5h in ‘Falster’ and 17.5 in ‘Kleppe’ (Norway). The critical number of LD cycles varied correspondingly. While the Central and North European varieties required fewer LD cycles for 50% heading at 18 than at 12°C, ‘Veyo’ showed the opposite response. It is concluded that the requirements for both primary and secondary induction of Lolium perenne increase with increasing latitude of origin of the germplasm. In one experiment, 39–87% of the inflorescences came from tillers that were not visible on transfer from primary to secondary induction, thus it is also concluded that there is no juvenile stage in tillers of Lolium perenne.

Acclimation to freezing temperatures in perennial ryegrass (Lolium perenne)

The increasing demands being placed on natural grasslands in the era following the appearance of Bovine Spongiform Encephalitis require that forage crops provide a reliable extended season of growth, combined with good winter survival to ensure sward longevity. The ability to tolerate sub-zero temperatures is integral to the survival of perennial forages. Since the development of freezing tolerance is crucial to the survival and productivity of over-wintering crops, forage breeding programmes require an improved understanding of the individual characteristics that contribute to tolerance to sub-zero temperatures. Photosynthesis, carbohydrate content and changes in protein composition were investigated in two varieties of Lolium perenne which differ in their response to growth at low temperature.

Incidence ofFusaria and occurrence of selected Fusarium mycotoxins on Lolium spp. in Germany

Test plantings with varieties ofLolium multiflorum andL perenne were harvested 4 to 7 times a year in 1991 and 1992. Samples were checked for the presence ofFusaria, the mycotoxins zearalenone, T-2 toxin, and diacetoxyscirpenol (DAS). Spectrum of species and the incidence ofFusaria and fusariotoxins are discussed in relation to the influencing factors site, variety ofLolium, harvesting time and year. Depending on these factors, 41 % to 100 % of the samples wereFusarium positive. Differences in infestation with Fusarium among varieties ofLolium perenne were dependent on location and did not correlate with yield. The six species ofFusarium pathogenic toLolium spp. (F. graminearum, F. culmorum, F. avenaceum, F. oxysporum, F. solani, and F. acuminatum) totaled 35.7 % of all the isolated strains. 14 species could be isolated fromLolium samples (descending frequency):F. culmorum, F. sambucinum, F. equiseti, F. acuminatum, F. semitectum, F. oxysporum, F. subglutinans, F. avenaceum, F. sporotrichioides, F. proliferatum, F. tricinctum, F. anthophilum, F. dimerum and F. graminearum. For the detection ofFusaria a promising new immunological method is presented. It is based on the genus specific production of exopolysaccharides byFusarium species.Mycotoxin contents in grass ranged from 0.01 to 4.75 ppm for zearalenone with 67 % positive samples and 0.3 % samples above 1 ppm, 0.04 to 2.78 ppm for T-2 toxin with 25 % positive samples and 2.8 % samples above 1 ppm, and 0.003 to 0.06 for DAS with 21.6 % positive samples. In silages, no T-2 toxin was detectable. IsolatedFusarium strains were checked for the ability to produce the mycotoxins zearalenone, T-2 toxin and DAS in culture. Most of the strains were positive for at least one of the toxins.

Suspension culture performance in commercial varieties of perennial ryegrass (Lolium perenne L.)

Suspension culture performance in commercial varieties of perennial ryegrass was studied to assess the effect of variety on suspension culture response and plant regeneration. 179 suspension cultures were established from embryos of mature seeds of 21 varieties and one breeding population. Of these, 123 suspensions were morphogenic (21 varieties) and 66 suspensions (18 varieties) regenerated green plants. A number of suspension lines, originating from two different suspensions, retained the capacity for green plant formation for almost four years. Replicates performed with seed lots of different ages indicated that suspensions initiated from young seeds (1 year) were of better quality than suspensions initiated from older seeds (2–4 years). Varieties differed in their capacity to form morphogenic suspensions and suspensions capable of regenerating green plants, although the effect of variety was relatively small. It was concluded that responsive genotypes can be found within most varieties of Lolium perenne.

Hardening and Dehardening of Lolium perenne in Response to Fluctuating Temperatures

Hardening and dehardening responses of two contrasting varieties of Lolium perenne, measured as LT 50 , estimates, were followed in fluctuating temperature environments. Unhardened seedlings were exposed to hardening environments for 7, 14, and 21 d in all combinations of 2, 4, 6, 8 and 10 o C with either high day and low night temperatures or low day and high night temperatures

Growth Characteristics of Contrasting Varieties of Perennial Ryegrass (Lolium perenne L.)

AbstractA field experiment was conducted to study growth characteristics of contrasting varieties of Lolium perenne (early heading: Gremie; late heading Vigor) in different growth/regrowth periods during 1984 and 1985. A growth function was fitted to data of weekly measurements of dry matter production (DM) and leaf area index (L) to derive the following parameters according to quantitative analysis of plant growth: crop growth rate (C), relative growth rate (R), leaf area ratio (LAR) and leaf weight ratio (LWR). Furthermore phenological development of the swards was recorded.The chief differences in the growth potential of the varieties were found in primary growth on the one hand and in both investigated first regrowth periods on the other hand. In second and third regrowth periods no distinct differences were found either in DM nor in L regarding variety effects. In primary growth the early heading variety gained an advantage in DM, which was enhanced with prolonging growth period until the middle of June combined with a rapid reproductive development of the sward. Growth potential in the first regrowth period was determinated by the time of cutting in primary growth according to the development stage of the swards at cutting time. It was evident that highest values of DM and C were corresponding with a high amount of undamaged reproductive tillers in the sward. DM of vegetative summer regrowths were comparable, while in late summer/autumn under worsening environmental conditions a reduction in DM was observed. In opposite to that L developed rather similar in the investigated regrowth periods. According to this force of expression of L is discussed in relation to DM and phenological development of the swards.

Responses of Endophyte-Bearing and Endophyte-Free Varieties of Lolium perenne L. to Fungicide Treatment and Simulated Herbivory

Responses of Endophyte-Bearing and Endophyte-Free Varieties of Lolium perenne L. to Fungicide Treatment and Simulated Herbivory

Genetic improvement of yield of nitrogen of Lolium perenne pastures

Four varieties of Lolium perenne with similar flowering dates bred over a 30 year period were grown in an orthogonal plot trial with two contrasting harvesting frequencies and three levels of fertiliser (0.2, 0.4 and 0.6 t/ha of N annually). In the second harvest year, the nitrogen (N) content of herbage at each harvest was determined and the yields of N calculated. The newest variety (Ba 10761) gave a 20% higher mean annual yield of N than the oldest (S.321). The influence of variety in increasing the ratio of N recovered: N applied was as great or greater than the influence of harvesting frequency or level of applied N. There were small differences between varieties in N content (%N), N content being inversely related to N yield.