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We conducted a four-year cutting experiment on herbage yield, with three years focused on testing the effect of perennial ryegrass (PR) cultivars 'Elena DS', 'Raminta', and 'Verseka', along with a cultivar mixture and compositions with white clover (WC) and red clover (RC) diversity, on crude protein (CP), modified acid detergent fibre (MADF), neutral detergent fibre (NDF), water-soluble carbohydrates (WSC), and dry matter digestibility (DMD) content. PR cultivars and cultivar mixtures were sown alone (N150), and the PR 'Elena DS' and PR cultivar mixtures were also sown with each WC, or WC and RC (N0). The average four-year herbage productivity was the lowest in PR 'Elena DS' the and cultivar mixture/WC, followed by all of the pure PR swards, and the highest in PR 'Elena DS' and the cultivar mixture/WC+RC; however, the PR 'Elena DS'/WC+RC mixture had the highest legume proportion and CP content. There was less NDF but also WSC in swards with legumes, but higher CP content than in pure PR swards; however, the highest CP content was in mixtures with RC. Among the grasses, PR 'Verseka' had lower NDF contents and a higher WSC than PR 'Elena DS', 'Raminta', and the cultivar mixture. Overall, this study revealed significant differences in the productivity of PR cultivars with a potential yield difference of up to 1.7 t ha−1. [ABSTRACT FROM AUTHOR]

Rhizosphere microorganisms are crucial for enhancing plant stress resistance. Current studies have shown that Arbuscular mycorrhizal fungi (AMF) can facilitate vegetation recovery in heavy metal-contaminated soils through interactions with rhizosphere microbiota. However, the mechanisms by which AMF influences rhizosphere microbiota and plant growth under cadmium (Cd) stress remain unclear. In this study, Lolium perenne L. was inoculated with AMF (Rhizophagus irregularis) and grown in soils supplemented with Cd (0 mg kg−1, Cd0; 100 mg kg−1, Cd100). Plant biomass, antioxidant enzyme activities, peroxide content, Cd uptake, and rhizosphere bacterial community composition were evaluated. AMF inoculation reduced Cd influx in aboveground tissues, enhanced nutrient availability in the rhizosphere, and mitigated Cd biotoxicity. Additionally, AMF inoculation improved the scavenging efficiency of reactive oxygen species and alleviated oxidative stress in L. perenne, thereby mitigating biomass reduction. Moreover, AMF treatment increased leaf and root biomass by 342.94% and 41.31%, respectively. Furthermore, under the same Cd concentration, AMF inoculation increased bacterial diversity (as measured by the Shannon index) and reduced bacterial enrichment (as indicated by the ACE index). AMF promoted the enrichment of certain bacterial genera (e.g., Proteobacteria and Actinobacteria) in the Cd100 group. These findings suggest that AMF regulated the composition of the rhizosphere bacterial community and promoted the growth of potentially beneficial microorganisms, thereby enhancing the resistance of L. perenne to Cd stress. Cd contamination in soil severely limits plant growth and threatens ecosystem stability, highlighting the need to understand how AMF and rhizosphere microbes can enhance Cd tolerance in L. perenne. Therefore, inoculating plants with AMF is a promising strategy for enhancing their adaptability to Cd-contaminated soils. [ABSTRACT FROM AUTHOR]

Lawn performs best with minimum inputs when grown in mixtures using more than a single grass specie. A study was conducted under open field conditions to evaluate the performance of four lawn grass species as mono-stand and in mixtures under mid-hill conditions at the Experimental Farm of the Department of Floriculture and Landscape Architecture, Dr Yashwant Singh Parmar University of Horticulture and Forestry, Nauni, Solan (H.P.) during March, 2020 to March, 2021. The experiment was laid out in a randomized block design with twelve treatments and three replications. Data was recorded at fortnight intervals for total weed count, chlorophyll content, number of mowing, and overall presentability just after turf establishment. It was observed that all turf grass mixtures, performed better than the monostands, during the entire course of the study. Turf grass mixture (50% 'Agrostis stolonifera' + 20% 'Festuca rubra' + 20% 'Lolium perenne' + 10% 'Cynodon dactylon)' required least number of mowing and was presentable throughout the year attaining highest presentability score of 22.98. [ABSTRACT FROM AUTHOR]

Rhizosphere microorganisms are crucial for enhancing plant stress resistance. Current studies have shown that Arbuscular mycorrhizal fungi (AMF) can facilitate vegetation recovery in heavy metal-contaminated soils through interactions with rhizosphere microbiota. However, the mechanisms by which AMF influences rhizosphere microbiota and plant growth under cadmium (Cd) stress remain unclear. In this study, Lolium perenne L. was inoculated with AMF (Rhizophagus irregularis) and grown in soils supplemented with Cd (0 mg kg−1, Cd0; 100 mg kg−1, Cd100). Plant biomass, antioxidant enzyme activities, peroxide content, Cd uptake, and rhizosphere bacterial community composition were evaluated. AMF inoculation reduced Cd influx in aboveground tissues, enhanced nutrient availability in the rhizosphere, and mitigated Cd biotoxicity. Additionally, AMF inoculation improved the scavenging efficiency of reactive oxygen species and alleviated oxidative stress in L. perenne, thereby mitigating biomass reduction. Moreover, AMF treatment increased leaf and root biomass by 342.94% and 41.31%, respectively. Furthermore, under the same Cd concentration, AMF inoculation increased bacterial diversity (as measured by the Shannon index) and reduced bacterial enrichment (as indicated by the ACE index). AMF promoted the enrichment of certain bacterial genera (e.g., Proteobacteria and Actinobacteria) in the Cd100 group. These findings suggest that AMF regulated the composition of the rhizosphere bacterial community and promoted the growth of potentially beneficial microorganisms, thereby enhancing the resistance of L. perenne to Cd stress. Cd contamination in soil severely limits plant growth and threatens ecosystem stability, highlighting the need to understand how AMF and rhizosphere microbes can enhance Cd tolerance in L. perenne. Therefore, inoculating plants with AMF is a promising strategy for enhancing their adaptability to Cd-contaminated soils.

We conducted a four-year cutting experiment on herbage yield, with three years focused on testing the effect of perennial ryegrass (PR) cultivars ‘Elena DS’, ‘Raminta’, and ‘Verseka’, along with a cultivar mixture and compositions with white clover (WC) and red clover (RC) diversity, on crude protein (CP), modified acid detergent fibre (MADF), neutral detergent fibre (NDF), water-soluble carbohydrates (WSC), and dry matter digestibility (DMD) content. PR cultivars and cultivar mixtures were sown alone (N150), and the PR ‘Elena DS’ and PR cultivar mixtures were also sown with each WC, or WC and RC (N0). The average four-year herbage productivity was the lowest in PR ‘Elena DS’ the and cultivar mixture/WC, followed by all of the pure PR swards, and the highest in PR ‘Elena DS’ and the cultivar mixture/WC+RC; however, the PR ‘Elena DS’/WC+RC mixture had the highest legume proportion and CP content. There was less NDF but also WSC in swards with legumes, but higher CP content than in pure PR swards; however, the highest CP content was in mixtures with RC. Among the grasses, PR ‘Verseka’ had lower NDF contents and a higher WSC than PR ‘Elena DS’, ‘Raminta’, and the cultivar mixture. Overall, this study revealed significant differences in the productivity of PR cultivars with a potential yield difference of up to 1.7 t ha−1.

Simple Summary: Forage chicory is one of the common herbs that has been posited as a complementary species to the traditional ryegrass/white clover mix in pasture-based systems, presenting the benefits of improved mineral nutrition and high nutritive feed during late spring and summer when there is a deficit. This work synthesised data from 15 unique research publications, examining the effect of chicory on milk production and milk fatty acid composition. The results reveal that the effect of chicory on milk production differed as a function of control forage type. Chicory inclusion into the diet of lactating dairy cattle increased milk yield and solids (milk fat + protein) when compared with cows grazing grass-based swards but was similar when compared with cows grazing other forages such as legumes. The increases in milk production when chicory was compared with grasses were associated with concomitant increases in dry matter and metabolisable energy intakes. Moreover, the milk that cows on chicory produced was higher in Omega-3 fatty acids such as alpha linolenic acid, which improve its nutritional quality. In traditional ryegrass/white clover (Lolium perenne L./Trifolium repens L.) pastoral systems, forage herbs such as chicory (Cichorium intybus L.) present an opportunity to fill feed deficits during late spring and summer. Although multiple research publications have evaluated the efficacy of chicory for enhancing milk production and milk fatty acid (FA) profile, no publication has quantitatively synthesised the body of research. This systematic review and meta-analysis examined the effect of chicory on milk production and composition, as well as on the milk fatty acid composition of dairy cattle. A total of 29 comparisons from 15 unique research publications involving 597 dairy cattle were used to develop a dataset for analysis. Three-level random-effect and robust variance estimator models were used to account for the hierarchical structure of the data and the dependency of effect sizes within publications. Chicory inclusion increased milk yield when compared to grass-based diets {weighted mean difference (WMD) = 1.07 (95% CI 0.54–1.60) kg/cow/d, p < 0.001}, but it provided a similar milk yield when compared to other forages such as legumes and herbs {dicots; WMD = −0.30, (95% CI −89–0.29) kg/cow/day, p = 0.312}. Increases in milk yield were congruent with differences in DM intake (p = 0.09) and ME intakes (p = 0.003), being similar in chicory-fed and dicot-fed cows but higher than grass-fed cows. Chicory feeding's effect on milk solids was twice as high during mid lactation {154 days in milk; WMD = 0.13, (95% 0.081–0.175) kg/cow/day, p < 0.001} as during late lactation {219 days in milk; WMD = 0.06, (95% 0.003–0.13) kg/cow/day, p = 0.041}. In line with milk yield, greater and more significant effect sizes were found for alpha linolenic acid {ALA; WMD = 0.20 (95% CI 0.06–0.35) g/100 g FA, p = 0.011} when chicory was compared to grass species only. Comparing chicory with dicots suggests that chicory inclusion did not impact ALA concentrations {WMD = 0.001 (95% CI −0.02–0.2) g/100 g FA, p = 0.99}. There were no differences in conjugated linoleic acid concentration in the milk of cows fed chicory or control diets. The study provides empirical evidence of chicory's efficacy for improved milk production and milk fatty acid composition. [ABSTRACT FROM AUTHOR]

Abstract Water‐use efficiency (WUE) is an under‐researched but very important drought tolerance trait in forage breeding. This research estimated quantitative genetic parameters of morpho‐physiological traits linked to agronomic water‐use efficiency (WUEA) and its proxy measures based on δ13C (WUEi) or gas exchange (evapotranspiration, WUEAET, or stomatal conductance WUEASC) of genotypes from half‐sib families of Lolium perenne L. (PRG) in a simulated summer drought cycle. Principal component analysis (PCA) of trait data distinguished a group of PRG genotypes where high WUEA and dry matter yield was associated with deep rooting, leaf hydration at more negative leaf osmotic and water potential, and reduced soil moisture depletion. Plants with this trait association sustained net assimilation and postdefoliation regrowth in drought. However, WUEi, WUEASC, and WUEAET were poorly correlated with most traits of interest at p 0.7;p

In the framework of the evaluation, valorization and conservation of plant genetic resources, six natural populations belonging to two species of forage grasses, perennial ryegrass (Lolium perenne L.) and annual ryegrass (Lolium rigidum Gaud.) collected in different agro-ecological regions of Algeria, were used to assess the effects of four NaCl and Na2SO4 concentrations (0, 50, 100, 150 mM) on germination parameters: germination percentage (GP), germination rate index (GRI), mean germination time (MGT), salt tolerance index (STI), seedling vigor index (SVI), shoot and root length. Seeds were germinated in an incubator at 20°C for 12 days in a completely randomized design with five replicates. The results revealed significant effects of NaCl and Na2SO4, populations and their interactions on germination parameters. Salinity reduced GP, STI, VI, GRI, shoot and root length, but increased MGT, in contrast to control experiment (0 mM). An important decrease was globally observed in the two species in all parameters with the lowest values at 100 and 150 mM except MGT. Compared to NaCl, the decrease was more important under Na2SO4. Population LP1 of L. perenne and the three populations of L. rigidum in the control and in the two salts showed the highest means of GP, GRI and SVI. Populations LR3 of L. rigidum (arid area) and LP3 of L. perenne (sub humid area) were the most sensitive at 150 mM. The shorter MGT was obtained in population LP1 of L. perenne which seems to be more salt-tolerant toward the two salts than the annual L. rigidum. [ABSTRACT FROM AUTHOR]

The study was conducted in the experimental field of the Research Institute of Mountain Stockbreeding and Agriculture of Troyan, with the aim of determining the correlation and regression dependences between some basic chemical indicators and the energy nutritional value of perennial ryegrass and legume fodder crop grown in monoculture and mixed grasslands. Data analysis shows that the amount of crude protein has a statistically significant impact on the in vitro digestibility of dry matter (r = 0.82) and the number of feed units (r = 0.88 - for FUM and r = 0.87 - for FUG). The yield of fresh matter was positively correlated with the dry matter yield (r = 0.83), the amount of NDF (r = 0.74) and hemicellulose (r = 0.80). The high correlation and dependence between fiber components of perennial grasses and legume fodder crops gives a clear assessment for forage quality. The coefficients of determination between structural fiber components and crude fiber concentration ranged from R² = 0.5176 to R² = 0.9186, with very well-proven statistical significance of the equations. [ABSTRACT FROM AUTHOR]

Background. Environmental pollution with toxic compounds poses a danger to nature and humans. Various technologies for soil purification from toxic metals are being developed. Objective. The work was aimed to study the possibility of lawn grass using for soil purification from Cr(VI). Methods. Plant seeds (Festuca rubra L. 45%, Festuca arundinacea Schreb. 25%, Lolium perenne L. 20%, Poa pratensis L. 10%) were sown in a container at 24 °C and grown for two months to obtain a lawn. K2CrO4 was added to the soil (400 g) (variants: 1.0 g, No. 1 and 2.5 g, No. 2) The following parameters were determined in two, five and ten days after Cr(VI) addition to the soil: the content of Cr(VI) in the roots, aerial part, and the soil; the coefficient of Cr(VI) content reduction; total content of aerobic heterotrophic microorganisms (CFU/g). Results. In 2 days after Cr(VI) adding the roots accumulated Cr(VI) in more significant amounts than the leaves (16.6 and 15 times in No. 1 and No. 2). In 5 days, an increase in Cr(VI) concentration in the plants was detected. Cr(VI) concentration in the soil decreased in 5 days by 45.8 and 13.57 times in variants No. 1 and No. 2, respectively. Inhibition of soil microorganisms growth was detected. CFU number in the control sample was 7.2×108, and in experimental variants No. 1 and No. 2 – 5×106 and 1×106, respectively. Conclusions. The addition of K2CrO4 inhibited the growth of soil microorganisms. Lawn grasses composition was successfully used for Cr(VI) extraction from the soil. A notable (13.8 and 9.3 times) reduction in Cr(VI) content in the soil was observed in two days. This reduction progressed greatly in five days as well (91.8 and 85.0 times). Cr(VI) was accumulated in the root system and the leaves of the plants. Thus, the selected grasses can be used in bioremediation technologies to purify contaminated soil.

Water‐use efficiency (WUE) is an under‐researched but very important drought tolerance trait in forage breeding. This research estimated quantitative genetic parameters of morpho‐physiological traits linked to agronomic water‐use efficiency (WUEA) and its proxy measures based on δ13C (WUEi) or gas exchange (evapotranspiration, WUEAET, or stomatal conductance WUEASC) of genotypes from half‐sib families of Lolium perenne L. (PRG) in a simulated summer drought cycle. Principal component analysis (PCA) of trait data distinguished a group of PRG genotypes where high WUEA and dry matter yield was associated with deep rooting, leaf hydration at more negative leaf osmotic and water potential, and reduced soil moisture depletion. Plants with this trait association sustained net assimilation and postdefoliation regrowth in drought. However, WUEi, WUEASC, and WUEAET were poorly correlated with most traits of interest at p <.05. Another PCA revealed a weak association between WUEA and its proxy measures under conditions tested. Quantitative genetic parameters including high estimates of narrow‐sense heritability (hn2>0.7;p<.05) of WUEA and related traits emphasized the genetic potential of the key trait combination for selecting PRG for improved drought tolerance. Research findings highlight the relative importance of WUEA and its proxy measures in the broad definition of PRG drought tolerance for breeding purposes. [ABSTRACT FROM AUTHOR]

The experiment was conducted at the Research Institute of Mountain Stockbreeding and Agriculture, Troyan (Bulgaria) with the aim of establishing the impact of the fertilizers Nano Sulfur and Panamin Agro on the height, productivity and composition of sown grass stand from perennial ryegrass (Lolium perenne L.). The perennial ryegrass plants have proven to form the highest grass stand with the application of Panamin Agro biofertilizer (250 g/da). The harvested biomass registered 4.05 cm (at P <0.05) higher values of the trait compared to the control (67.18 cm). The highest average yield of fresh matter was registered in the grass stand of Lolium perenne L. treated with Panamin Agro - 250 g/da. The values of the trait significantly exceeded the unfertilized control by 16.87% (P <0.05). No significant difference was proven in the amount of dry matter was found between the fertilized variants and the untreated control of perennial ryegrass. Lolium perenne L. occupied the highest relative share in the variants treated with Nano Sulfur (200 ml/da) and Panamin Agro (250 g/da). The percentage share of the grass crop was respectively 89.94% and 88.71% (in the control variant - 79.95%). The specified variants had the lowest degree of weed infestation. [ABSTRACT FROM AUTHOR]

In traditional ryegrass/white clover (Lolium perenne L./Trifolium repens L.) pastoral systems, forage herbs such as chicory (Cichorium intybus L.) present an opportunity to fill feed deficits during late spring and summer. Although multiple research publications have evaluated the efficacy of chicory for enhancing milk production and milk fatty acid (FA) profile, no publication has quantitatively synthesised the body of research. This systematic review and meta-analysis examined the effect of chicory on milk production and composition, as well as on the milk fatty acid composition of dairy cattle. A total of 29 comparisons from 15 unique research publications involving 597 dairy cattle were used to develop a dataset for analysis. Three-level random-effect and robust variance estimator models were used to account for the hierarchical structure of the data and the dependency of effect sizes within publications. Chicory inclusion increased milk yield when compared to grass-based diets {weighted mean difference (WMD) = 1.07 (95% CI 0.54–1.60) kg/cow/d, p < 0.001}, but it provided a similar milk yield when compared to other forages such as legumes and herbs {dicots; WMD = −0.30, (95% CI −89–0.29) kg/cow/day, p = 0.312}. Increases in milk yield were congruent with differences in DM intake (p = 0.09) and ME intakes (p = 0.003), being similar in chicory-fed and dicot-fed cows but higher than grass-fed cows. Chicory feeding’s effect on milk solids was twice as high during mid lactation {154 days in milk; WMD = 0.13, (95% 0.081–0.175) kg/cow/day, p < 0.001} as during late lactation {219 days in milk; WMD = 0.06, (95% 0.003–0.13) kg/cow/day, p = 0.041}. In line with milk yield, greater and more significant effect sizes were found for alpha linolenic acid {ALA; WMD = 0.20 (95% CI 0.06–0.35) g/100 g FA, p = 0.011} when chicory was compared to grass species only. Comparing chicory with dicots suggests that chicory inclusion did not impact ALA concentrations {WMD = 0.001 (95% CI −0.02–0.2) g/100 g FA, p = 0.99}. There were no differences in conjugated linoleic acid concentration in the milk of cows fed chicory or control diets. The study provides empirical evidence of chicory’s efficacy for improved milk production and milk fatty acid composition.

The contamination of soil and water by metals such as mercury (Hg) and cadmium (Cd) has been increasing in recent years, because of anthropogenic activities such as mining and agriculture, respectively. In this work, the changes in the rhizosphere microbiome of Lolium perenne L. during the phytoremediation of soils contaminated with Hg and Cd were evaluated. For this, two soil types were sampled, one inoculated with mycorrhizae and one without. The soils were contaminated with Hg and Cd, and L. perenne seeds were sown and harvested after 30 days. To assess changes in the microbiome, DNA isolation tests were performed, for which samples were subjected to two-step PCR amplification with specific 16S rDNA V3-V4 primers (337F and 805R). With mycorrhizae, changes had been found in the absorption processes of metals and a new distribution. While with respect to microorganisms, families such as the Enterobacteriaceae have been shown to have biosorption and efflux effects on metals such as Hg and Cd. Mycorrhizae then improve the efficiency of removal and allow the plant to better distribute the absorbed concentrations. Overall, L. perenne is a species with a high potential for phytoremediation of Cd- and Hg-contaminated soils in the tropics. Inoculation with mycorrhizae modifies the phytoremediation mechanisms of the plant and the composition of microorganisms in the rhizosphere. Mycorrhizal inoculation and changes in the microbiome were associated with increased plant tolerance to Cd and Hg. Microorganism-assisted phytoremediation is an appropriate alternative for L. perenne. [ABSTRACT FROM AUTHOR]

The market success of perennial ryegrass (Lolium perenne L.) cultivars depends on sufficient seed production, as they are propagated by seed. However, breeding for high quality forage production reduces seed yield, and breaking the negative correlation would help to overcome the problem. The foliar disease crown rust is another factor affecting reproductive capacity and thereby seed yield. We evaluated seed yield-related traits and resistance to crown rust in a collection of commercial cultivars and ecotypes of perennial ryegrass and identified genome-wide markers associated with the traits. The study revealed high variation between the ecotype and cultivar groups as well as between years. A genome-wide association study identified 17 DNA single-nucleotide polymorphisms (SNPs) of which eight were associated with crown rust and nine with flag-leaf length. The SNP markers were located within or near predicted genes functioning in defense against pathogens. The identified genes are strong candidates for a further in-depth functional study to continue unravel determination of leaf architecture and crown rust resistance in perennial ryegrass.

Abstract Methyl jasmonate (MeJA) plays a role in improving plant stress tolerance. The molecular mechanisms associated with heat tolerance mediated by MeJA are not fully understood in perennial grass species. The study was designed to explore transcriptomic mechanisms underlying heat tolerance by exogenous MeJA in perennial ryegrass (Lolium perenne L.) using RNA-seq. Transcriptomic profiling was performed on plants under normal temperature (CK), high temperature for 12 h (H), MeJA pretreatment (T), MeJA pretreatment + H (T-H), respectively. The analysis of differentially expressed genes (DEGs) showed that H resulted in the most DEGs and T had the least, compared with CK. Among them, the DEGs related to the response to oxygen-containing compound was higher in CKvsH, while many genes related to photosynthetic system were down-regulated. The DEGs related to plastid components was higher in CKvsT. GO and KEGG analysis showed that exogenous application of MeJA enriched photosynthesis related pathways under heat stress. Exogenous MeJA significantly increased the expression of genes involved in chlorophyll (Chl) biosynthesis and antioxidant metabolism, and decreased the expression of Chl degradation genes, as well as the expression of heat shock transcription factor - heat shock protein (HSF-HSP) network under heat stress. The results indicated that exogenous application of MeJA improved the heat tolerance of perennial ryegrass by mediating expression of genes in different pathways, such as Chl biosynthesis and degradation, antioxidant enzyme system, HSF-HSP network and JAs biosynthesis.

With developments in industry, petroleum and heavy metal pollution are increasingly affecting soil, significantly harming the environment, biosecurity, and human health. Therefore, the remediation of contaminated soil is becoming increasingly important. In this study, ryegrass (Lolium perenne L.) was planted in petroleum–heavy metal co-contaminated soil with the application of nitrogen and phosphorus fertilizers. Three treatments were set up: uncontaminated soil + ryegrass (SH); petroleum–heavy metal co-contaminated soil + ryegrass (SPGH); and petroleum–heavy metal co-contaminated soil + ryegrass + nitrogen and phosphorus fertilizer (SPGH + NP). The results showed that the petroleum–heavy metal co-contamination promoted increases in the root length, surface area, volume, and diameter of ryegrass roots, increasing the below-ground biomass and decreasing the photosynthetic pigment content in the early stages of the experiment. The ratios of chlorophyll a/b and chlorophyll/carotenoid also increased. However, the application of fertilizer reduced the length, surface area, volume, and diameter of ryegrass roots in the co-contaminated soil, and the below-ground biomass decreased while the above-ground biomass increased. Furthermore, the photosynthetic pigment content was significantly higher than that in the unfertilized treatment and the chlorophyll a/b ratio decreased while the chlorophyll/carotenoid ratio increased. Therefore, fertilizers could alleviate the toxic effects of petroleum–heavy metal combined pollution on ryegrass roots and promote the synthesis of chlorophyll and other pigments, thus reducing the inhibitory effect of petroleum–heavy metal combined pollution on ryegrass growth and facilitating the remediation of the polluted soil. [ABSTRACT FROM AUTHOR]

In the period 2020-2022, in the experimental field of RIMSA – Troyan, a comparative test of perennial ryegrass (Lolium perenne L.) varieties was conducted in the direction of forage productivity. According to the results, the genotypic factor, respectively the choice of variety, has a significant impact on the productivity of independent cultivation of pasture ryegrass in the mountainous conditions of Northern Bulgaria. The highest dry matter yield, on average for the period, was registered for Nui (1161 kg/da) and Tetramis (1146 kg/da). Maximum height and lowest phenotypic variability by year were formed by the cultivars Tetramis (69.28 cm) and Nui (67.93 cm). The Bulgarian cultivarsultivar, such as the diploid standard c Harmoniya and the tetraploid Tetramis and Tetrani had equal productivity for a medium-long period of use. The grass stands of the Nira and Bokser cultivars were proven to have a lower yield of fresh and dry matter compared to the standard (Harmoniya). [ABSTRACT FROM AUTHOR]

The purpose of the experiment is to determine the composition and energy value of fodder from monoculture and mixed grass stands of perennial ryegrass with legume fodder crops under mountain conditions. It was found that the concentration of the fiber components of the cell walls in the monoculture grass stands of perennial ryegrass was significantly higher compared to the mixed ones, which affected the forage mass digestibility. The highest dry matter digestibility was registered in the biomass of Lolium perenne L. + Trifolium repens L. mixture (642.54 g kg-1 DM) followed by Lolium perenne L. + Lotus corniculatus L. (636.28 g kg-1 DM) and Lolium perenne L. + Trifolium pratense L. (622.18 g kg-1 DM). The monoculture grass stands with red clover had the highest content of neutral detergent fibers (418.03 g kg-1 DM), whereas the bird's-foot-trefoil biomass had the highest concentration of acid detergent fibers (291.98 g kg-1 DM), acid-detergent lignin (70.72 g kg-1 DM) and cellulose (221.27 g kg-1 DM). The forage mass of pasture ryegrass registered lower values for all the investigated parameters compared to its mixtures with leguminous forage crops. The highest caloric content is the harvested grass stands of Lolium perenne L. with Lotus corniculatus L. (17.48 MJ/kg DM). Biomass also has the highest average value of energy useful for the normal course of physiological needs in the animal organism (7.45 MJ/kg DM), as well as in terms of the number of feed units for milk (0.68 in kg DM) and growth (0.62 in kg DM). [ABSTRACT FROM AUTHOR]

This paper presents the effects of the physiological reaction of the main cool-season grass species used for turf in a temperate climate: perennial ryegrass, Kentucky bluegrass, and tall fescue, on a twice-a-year trinexapac-ethyl (TE) application in late spring and early autumn, seasons of rapid turf growth. The fully established turf plots in the split-plot system of three replicates, with three cultivars/species, were treated by TE (1.5 and 4.5 g/100 m2). The 4.5 g/100 m2 was harmful to Kentucky bluegrass. The perennial ryegrass responded by dose-dependent growth inhibition; 30–60% in spring and 25–40% in autumn for lower and higher doses, respectively. Tall fescue responded by 50% growth inhibition independently of concentration and season. Plant physiological responses, visualized as graphs of fluorescence data, revealed the stress of Kentucky bluegrass upon high TE dose. Based on principal component analysis (PCA) analysis, three groups were distinguished: perennial ryegrass varieties from high and low TE treatments and Kentucky bluegrass varieties from high TE. TE-dependent growth reduction with no significant quality decrease benefits the environment by reducing carbon footprint machine operations (mowing). Utilizing fluorescence measurement may help to manage turf physiology. [ABSTRACT FROM AUTHOR]

Perennial ryegrass (Lolium perenne L.) is an important turfgrass and gramineous forage widely grown in temperate regions around the world. However, its perennial nature leads to the inevitable exposure of perennial ryegrass to various environmental stresses on a seasonal basis and from year to year. Like other plants, perennial ryegrass has evolved sophisticated mechanisms to make appropriate adjustments in growth and development in order to adapt to the stress environment at both the physiological and molecular levels. A thorough understanding of the mechanisms of perennial ryegrass response to abiotic stresses is crucial for obtaining superior stress-tolerant varieties through molecular breeding. Over the past decades, studies of perennial ryegrass at the molecular and genetic levels have revealed a lot of useful information to understand the mechanisms of perennial ryegrass adaptation to an adverse environment. Unfortunately, molecular mechanisms by which perennial ryegrass adapts to abiotic stresses have not been reviewed thus far. In this review, we summarize the recent works on the genetic and molecular mechanisms of perennial ryegrass response to the major abiotic stresses (i.e., drought, salinity, and extreme temperatures) and discuss new directions for future studies. Such knowledge will provide valuable information for molecular breeding in perennial ryegrass to improve stress resistance and promote the sustainability of agriculture and the environment. [ABSTRACT FROM AUTHOR]

Understanding the differences in cool-season turfgrass responses to shade is critical for future turfgrass management and breeding for improved shade tolerance. The purpose of this study was to evaluate the shade-tolerance mechanisms of two cool-season turfgrass species in terms of turf performance, growth, and physiological characteristics. Two turfgrass species, namely, 'SupraNova' (Poa. supina Schrad.) and 'Lark' (Lolium perenne L.), were subjected to 0 (CK, unshaded), 35% (LS), 70% (MS), and 92% (HS) shade, respectively. Compared with 'Lark', 'SupraNova' showed better turf quality (TQ) and turf color intensity (TCI) under shade. The total length and surface area of the roots of 'Lark' gradually decreased as the shade increased, while those of 'SupraNova' increased and then decreased with increasing shade. The chlorophyll fluorescence photochemical quenching coefficient (qP), electron transport rate (ETR), and maximum quantum yield of primary photosystem II (PSII) photochemistry (Fv/Fm) decreased significantly under HS; however, these decreases were more significant in 'Lark' than in 'SupraNova'. The leaf reflectance of the two turfgrasses under shade was lower than that under CK, but the leaf reflectance of 'Lark' was higher than that of 'SupraNova' in the visible light band. The normalized difference vegetation index (NDVI) of the two grasses first decreased and then increased. The NDVI of 'Lark' under shade was slightly higher than that under CK. 'SupraNova' showed strong tolerance on the basis of malondialdehyde (MDA), hydrogen peroxide (H2O2), superoxide anion (O2·−), and ascorbic acid (AsA) contents and superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) activity. The MDA, H2O2, O2·−, and AsA contents and SOD, POD, and CAT activity (which represent indicators) changed the most under MS. Taken together, the results indicated that the adaptability of 'SupraNova' to shade was better than that of 'Lark'. [ABSTRACT FROM AUTHOR]

The market success of perennial ryegrass (Lolium perenne L.) cultivars depends on sufficient seed production, as they are propagated by seed. However, breeding for high quality forage production reduces seed yield, and breaking the negative correlation would help to overcome the problem. The foliar disease crown rust is another factor affecting reproductive capacity and thereby seed yield. We evaluated seed yield-related traits and resistance to crown rust in a collection of commercial cultivars and ecotypes of perennial ryegrass and identified genome-wide markers associated with the traits. The study revealed high variation between the ecotype and cultivar groups as well as between years. A genome-wide association study identified 17 DNA single-nucleotide polymorphisms (SNPs) of which eight were associated with crown rust and nine with flag-leaf length. The SNP markers were located within or near predicted genes functioning in defense against pathogens. The identified genes are strong candidates for a further in-depth functional study to continue unravel determination of leaf architecture and crown rust resistance in perennial ryegrass. [ABSTRACT FROM AUTHOR]

Methyl jasmonate (MeJA) plays a role in improving plant stress tolerance. The molecular mechanisms associated with heat tolerance mediated by MeJA are not fully understood in perennial grass species. The study was designed to explore transcriptomic mechanisms underlying heat tolerance by exogenous MeJA in perennial ryegrass (Lolium perenne L.) using RNA-seq. Transcriptomic profiling was performed on plants under normal temperature (CK), high temperature for 12 h (H), MeJA pretreatment (T), MeJA pretreatment + H (T-H), respectively. The analysis of differentially expressed genes (DEGs) showed that H resulted in the most DEGs and T had the least, compared with CK. Among them, the DEGs related to the response to oxygen-containing compound was higher in CKvsH, while many genes related to photosynthetic system were down-regulated. The DEGs related to plastid components was higher in CKvsT. GO and KEGG analysis showed that exogenous application of MeJA enriched photosynthesis related pathways under heat stress. Exogenous MeJA significantly increased the expression of genes involved in chlorophyll (Chl) biosynthesis and antioxidant metabolism, and decreased the expression of Chl degradation genes, as well as the expression of heat shock transcription factor - heat shock protein (HSF-HSP) network under heat stress. The results indicated that exogenous application of MeJA improved the heat tolerance of perennial ryegrass by mediating expression of genes in different pathways, such as Chl biosynthesis and degradation, antioxidant enzyme system, HSF-HSP network and JAs biosynthesis. [ABSTRACT FROM AUTHOR]

Im Rahmen der alljährlichen Untersuchung von Verdachtsproben auf Herbizidresistenz aus Rheinland-Pfalz wurde 2018 eine Herkunft von Deutschem Weidelgras (Lolium perenne L.) in einem Obstbaubetrieb in Rheinhessen gesammelt. Deutsches Weidelgras wird dort häufig zur Fahrgassenbegrünung eingesät und kann von dort in die herbizidbehandelten Baumzeilen einwandern. Durch mehrere Biotests am Dienstleistungszentrum Ländlicher Raum (Bad Kreuznach) und an der Bayerischen Landesanstalt für Landwirtschaft (Freising) in den Jahren 2018 und 2019 konnten mögliche Einflussfaktoren auf die festgestellten Minderwirkungen wie Applikationstechnik und Produktformulierung ausgeschlossen werden. Der Vergleich mit einer Glyphosat-sensitiven L. perenne ermöglichte den Nachweis der Glyphosatresistenz.

Perennial ryegrass is an important forage crop in dairy farming, either for grazing or haying purposes. To further optimise the forage use, this study focused on understanding forage digestibility in the two most important cuts of perennial ryegrass, the spring cut at heading and the autumn cut. In a highly diverse collection of 592 Lolium perenne genotypes, the organic matter digestibility (OMD) and underlying traits such as cell wall digestibility (NDFD) and cell wall components (cellulose, hemicellulose, and lignin) were investigated for 2 years. A high genotype × season interaction was found for OMD and NDFD, indicating differences in genetic control of these forage quality traits in spring versus autumn. OMD could be explained by both the quantity of cell wall content (NDF) and the quality of the cell wall content (NDFD). The variability in NDFD in spring was mainly explained by differences in hemicellulose. A 1% increase of the hemicellulose content in the cell wall (HC.NDF) resulted in an increase of 0.81% of NDFD. In autumn, it was mainly explained by the lignin content in the cell wall (ADL.NDF). A 0.1% decrease of ADL.NDF resulted in an increase of 0.41% of NDFD. The seasonal traits were highly heritable and showed a higher variation in autumn versus spring, indicating the potential to select for forage quality in the autumn cut. In a candidate gene association mapping approach, in which 503 genes involved in cell wall biogenesis, plant architecture, and phytohormone biosynthesis and signalling, identified significant quantitative trait loci (QTLs) which could explain from 29 to 52% of the phenotypic variance in the forage quality traits OMD and NDFD, with small effects of each marker taken individually (ranging from 1 to 7%). No identical QTLs were identified between seasons, but within a season, some QTLs were in common between digestibility traits and cell wall composition traits confirming the importance of hemicellulose concentration for spring digestibility and lignin concentration in NDF for autumn digestibility.

Various adaptive mechanisms can ensure that seedlings are established at the most favourable time and place. These mechanisms include seed dormancy i.e., incapacity to germinate in any environment without a specific environmental trigger and inhibition i.e., incapacity to germinate in an unfavourable environment (water availability, temperature: thermoinhibition and light). The objective of this research was to study in the temperate range for germination of forage and turf grass species perennial ryegrass, if the thermal requirements for germination are under genetic controlled and could be selectively bred. Two divergent selections of three cycles were realized on a natural population: one to select for the capacity to germinate at 10°C vs. the impossibility to germinate at 10°C, and one to select for the capacity to germinate at 32°C vs. the impossibility to germinate at 32°C. Seeds of all the lots obtained from the two divergent selections were then germinated at constant temperatures from 5 to 35°C to evaluate their germination ability. Concerning the positive selection, the first cycle of positive selection at 10°C was highly efficient with a very strong increase in the germination percentage. However, afterward no selection effect was observed during the next two cycles of positive selection. By contrast, the positive selection at 32°C was efficient during all cycles with a linear increase of the percentage of germination at 32°C. Concerning the negative selection, we observed only a large positive effect of the first cycle of selection at 10°C. These findings demonstrate that seed thermoinhibition at 10 and 32°C observed in a natural population of perennial ryegrass has a genetic basis and a single recessive gene seems to be involved at 10°C.

Various adaptive mechanisms can ensure that seedlings are established at the most favourable time and place. These mechanisms include seed dormancy i.e., incapacity to germinate in any environment without a specific environmental trigger and inhibition i.e., incapacity to germinate in an unfavourable environment (water availability, temperature: thermoinhibition and light). The objective of this research was to study in the temperate range for germination of forage and turf grass species perennial ryegrass, if the thermal requirements for germination are under genetic controlled and could be selectively bred. Two divergent selections of three cycles were realized on a natural population: one to select for the capacity to germinate at 10°C vs. the impossibility to germinate at 10°C, and one to select for the capacity to germinate at 32°C vs. the impossibility to germinate at 32°C. Seeds of all the lots obtained from the two divergent selections were then germinated at constant temperatures from 5 to 35°C to evaluate their germination ability. Concerning the positive selection, the first cycle of positive selection at 10°C was highly efficient with a very strong increase in the germination percentage. However, afterward no selection effect was observed during the next two cycles of positive selection. By contrast, the positive selection at 32°C was efficient during all cycles with a linear increase of the percentage of germination at 32°C. Concerning the negative selection, we observed only a large positive effect of the first cycle of selection at 10°C. These findings demonstrate that seed thermoinhibition at 10 and 32°C observed in a natural population of perennial ryegrass has a genetic basis and a single recessive gene seems to be involved at 10°C. [ABSTRACT FROM AUTHOR]

Perennial ryegrass is an important forage crop in dairy farming, either for grazing or haying purposes. To further optimise the forage use, this study focused on understanding forage digestibility in the two most important cuts of perennial ryegrass, the spring cut at heading and the autumn cut. In a highly diverse collection of 592 Lolium perenne genotypes, the organic matter digestibility (OMD) and underlying traits such as cell wall digestibility (NDFD) and cell wall components (cellulose, hemicellulose, and lignin) were investigated for 2 years. A high genotype × season interaction was found for OMD and NDFD, indicating differences in genetic control of these forage quality traits in spring versus autumn. OMD could be explained by both the quantity of cell wall content (NDF) and the quality of the cell wall content (NDFD). The variability in NDFD in spring was mainly explained by differences in hemicellulose. A 1% increase of the hemicellulose content in the cell wall (HC.NDF) resulted in an increase of 0.81% of NDFD. In autumn, it was mainly explained by the lignin content in the cell wall (ADL.NDF). A 0.1% decrease of ADL.NDF resulted in an increase of 0.41% of NDFD. The seasonal traits were highly heritable and showed a higher variation in autumn versus spring, indicating the potential to select for forage quality in the autumn cut. In a candidate gene association mapping approach, in which 503 genes involved in cell wall biogenesis, plant architecture, and phytohormone biosynthesis and signalling, identified significant quantitative trait loci (QTLs) which could explain from 29 to 52% of the phenotypic variance in the forage quality traits OMD and NDFD, with small effects of each marker taken individually (ranging from 1 to 7%). No identical QTLs were identified between seasons, but within a season, some QTLs were in common between digestibility traits and cell wall composition traits confirming the importance of hemicellulose concentration for spring digestibility and lignin concentration in NDF for autumn digestibility. [ABSTRACT FROM AUTHOR]

Agricultural grass cultivars bred for increased forage yield commonly have extensive root systems. As roots are an important input of organic matter into the soil, it follows that such cultivars could lead to important increases in soil organic carbon (SOC), but this, and the mechanisms involved, are poorly understood with little empirical field evidence. We assessed the effect of two cultivars, Lolium perenne L. cv. "AberMagic" and L. perenne L. × Festuca pratensis Huds. cv. "Prior", in comparison with mixed‐species permanent pasture ("Pasture") in a field experiment on temperate alluvial soil in the southwest UK. Root and SOC stocks, and specific plant‐derived lipids as mechanistic biomarkers for shoot and root inputs of C, were measured on intact 1‐m volumetric soil cores collected on four dates in 2013–2015. Total grass yields were greater for both grass cultivars (40–43 Mg ha−1) than Pasture (39 Mg ha−1), and by 2015 root stocks in the upper 0.1 m were significantly greater by more than 4.7 Mg ha−1. At 0.1–0.3 m depth, SOC stocks (per 0.1‐m depth) were significantly greater under the two grass cultivars (24–50 Mg ha−1) compared to Pasture (18–32 Mg ha−1). In the full 1‐m profile, mean SOC stocks were 137, 133 and 110 Mg ha−1 for AberMagic, Prior and Pasture, respectively, matching root biomass distribution. Odd‐chain n‐alkane concentrations were significantly greater for shoots than roots (274 vs. 64 mg kg−1, respectively), and roots had significantly greater concentrations than shoots of even‐chain hydroxy fatty acids (1829 vs. 305 mg kg−1, respectively) and diacids (317 vs. 93 mg kg−1, respectively). This confirmed lipids as candidate biomarkers for distinguishing shoot and root inputs into the soil, with roots being the dominant source of SOC. Based on the observations of increased forage yield and SOC stock, high‐yielding forage grass cultivars can contribute to future strategies for climate‐smart agriculture in grassland‐dominated temperate regions. Highlights: Selected root traits for increased depth, density and diameter may increase SOC in grassland.The effect of two high‐yielding forage grass cultivars were assessed in a field trial.Fast‐growing, high‐yielding cultivars enhanced root and SOC stocks compared to typical pasture.Lipid biomarkers confirmed that root inputs were the predominant C input to soil. [ABSTRACT FROM AUTHOR]

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The sustainability of warm-season turfgrass species in winter dormancy is a major concern in Mediterranean ecology. The concept of overseed a lawn has been still new for many developing countries such as Turkey as part of a regular maintenance. Therefore, a 2-year study was conducted at the experimental fields of Ege University, Izmir/Turkey during 2014-2016 years to compare the effects of four different overseeding times (September 15, September 30, October 15 and October 30) on four warm season turfgrass species (Cynodon dactylon cv. SR9554, Cynodon dactylon × Cynodon transvaalensis cv. Tifway-419, Paspalum vaginatum cv. Sea Spray and Zoysia japonica cv. Zenith) by measuring visual turf quality (1-9 score) and some related characteristics as texture (mm), cover (1-9 score), weed infestation (1-9 score) and colour (1-9 score). ‘50% cv. Troya+50% cv. Esquire’ perennial ryegrass (Lolium perenne L.) mixture was used for overseeding in trial. According to results, visual turf quality performance of 6.0 scores and above were obtained from all treatments. We concluded that October 15 should be most suitable time for overseeding applications. Additionally, L. perenne L. can be practiced successfully in Mediterranean region in order to eliminate the concerns of warm-season turfgrasses in the winter dormancy period observed in cold temperatures. Highlights - No gaps were formed in plots and high coverage degrees were maintained during overseeding periods in all treatments. - Homogeneous spring transition was occurred from Lolium perenne L. to warm-season turfgrass species in all overseeding times. - Visual turf quality performance of 6.0 scores and above which is acceptable level were obtained from all overseeding times. - Better results were obtained from overseeding applications on Paspalum vaginatum and Cynodon dactylon × Cynodon transvaalensis. - The different results among the warm-season turfgrass species can provide effective information for future research studies.

Plants generally behave in different response mechanisms under stress. This study aims to reveal the effects of biochar on photosynthesis and antioxidant system of ryegrass and alfalfa at the early stage of salt-alkali stress. Four treatments were conducted in the pot experiment: saline-alkali stress treatment (C0, 150 mmol/L equal mol NaCl, Na2CO3, NaHCO3 mixed saline solution), saline-alkali stress +1% biochar (C1), saline-alkali stress +3% biochar (C2), saline-alkali stress +5% biochar (C3), and set blank control (CK) without additives. Conventional cultivation was also carried out before the experiment, and then a stress test was conducted 40 d later. The stress treatment lasted for a total of 14 d, where 100 mL mixed saline solution was added to C0, C1, C2, and C3 treatments at one time, and 100 mL deionized water was added to CK treatment. Subsequently, the response of ryegrass and alfalfa was determined on the 14th day of the experiment, including growth indices, photosynthetic characteristics, malondialdehyde content, and antioxidant enzyme activities under various levels of biochar addition. The results showed as follows: 1) 14 d salt-alkali treatment dominated the growth of ryegrass and alfalfa. Specifically, there was a significant decrease in biomass accumulation, net photosynthetic rate, stomatal conductance, transpiration rate, and intercellular CO2 concentration. But there was no significant effect on the chlorophyll content and root length. Furthermore, the content of malondialdehyde increased significantly, indicating the antioxidant system responded positively. Similarly, the activities of superoxide dismutase, peroxidase, and catalase increased to alleviate the saline-alkali stress on plants. 2) The addition of biochar effectively improved the stress resistance of perennial ryegrass and alfalfa, thereby inducing a positive response in the antioxidant system. As such, the salinity-alkalinity stress was effectively relieved, particularly from the osmotic stress. The malondialdehyde content decreased obviously, whereas the alfalfa superoxide dismutase increased significantly, indicating that the perennial ryegrass antioxidant system was given a priority with the decomposition of hydrogen peroxide enzyme. The biomass, plant height, and root length of ryegrass and alfalfa increased by 48.50%-82.34%, 31.19%--44.16%, and 17.15%-48.09%, respectively, under 3% biochar treatment, compared with that under the salt-alkali stress. Additionally, the stomatal conductance and transpiration rate increased by 118.69%-358.99%, and 98.66%-526.53%, and the chlorophyll content and net photosynthetic rate increased by 7.97% and 519.09%, respectively. 3) The antioxidant enzyme activities and malondialdehyde content of ryegrass and alfalfa remained stable or decreased with the increase of biochar amount under the short-term salt-alkali stress. A trend was also found that the promoting at a low supplemental level and inhibiting at a high supplemental level for the growth indexes and photosynthetic characteristics. Consequently, there was a significant effect of salinity-alkalinity stress on the growth of perennial ryegrass and alfalfa, where a positive response was found at the beginning of stress. Correspondingly, an optimal addition of biochar can be expected to improve the stress resistance of perennial ryegrass and alfalfa, while the positive reaction of the oxidation system can effectively relieve the short-term salinity-alkalinity stress. The best effect was also achieved in the 3% biochar application. The findings can provide a sound reference for the scientific application of biochar to promote crop growth and yield. [ABSTRACT FROM AUTHOR]

Remediation using plant-microbe interactions is an efficient and cost-effective technique. However, few studies have reported their effects in phosphate mining wastelands. In this study, two native phosphate-solubilizing microorganisms (PSM) (Trichoderma asperellum LZ1 and Serratia sp. LX2) and two native plants (Lolium perenne L. and Lactuca versicolor) were used to remediate excess phosphorus (P) contamination in phosphate mining wasteland soil. In pot experiments, PSM was found to increase P availability by reducing soil pH. The inoculation of strain LZ1 and LX2 significantly increased the total biomass of L. perenne L. by 41.73%, 6.27%, and 49.26%, respectively. Similarly, L. versicolor biomass also increased by 17.51%, 11.67%, and 41.16%, respectively. In addition, the root, shoot length, and chlorophyll content of L. perenne L. and L. versicolor were also significantly higher than those of the treatments inoculated without PSM. In PSM-inoculated soils, the P accumulation in L. perenne L. and L. versicolor was 11.71 and 5.54 mg/pot, respectively. The findings in this study showed that T. asperellum LZ1 and Serratia sp. LX2 could effectively promote the growth of L. perenne L. and L. versicolor, and increase the P accumulation in plants, which would be beneficial to the phytoremediation of excess P contamination in phosphate mining wasteland. [ABSTRACT FROM AUTHOR]

The sustainability of warm-season turfgrass species in winter dormancy is a major concern in Mediterranean ecology. The concept of overseed a lawn has been still new for many developing countries such as Turkey as part of a regular maintenance. Therefore, a 2-year study was conducted at the experimental fields of Ege University, Izmir/Turkey during 2014-2016 years to compare the effects of four different overseeding times (September 15, September 30, October 15 and October 30) on four warm season turfgrass species (Cynodon dactylon cv. SR9554, Cynodon dactylon × Cynodon transvaalensis cv. Tifway-419, Paspalum vaginatum cv. Sea Spray and Zoysia japonica cv. Zenith) by measuring visual turf quality (1-9 score) and some related characteristics as texture (mm), cover (1-9 score), weed infestation (1-9 score) and colour (1-9 score). '50% cv. Troya+50% cv. Esquire' perennial ryegrass (Lolium perenne L.) mixture was used for overseeding in trial. According to results, visual turf quality performance of 6.0 scores and above were obtained from all treatments. We concluded that October 15 should be most suitable time for overseeding applications. Additionally, L. perenne L. can be practiced successfully in Mediterranean region in order to eliminate the concerns of warm-season turfgrasses in the winter dormancy period observed in cold temperatures. [ABSTRACT FROM AUTHOR]

This paper presents the effects of the physiological reaction of the main cool-season grass species used for turf in a temperate climate: perennial ryegrass, Kentucky bluegrass, and tall fescue, on a twice-a-year trinexapac-ethyl (TE) application in late spring and early autumn, seasons of rapid turf growth. The fully established turf plots in the split-plot system of three replicates, with three cultivars/species, were treated by TE (1.5 and 4.5 g/100 m2). The 4.5 g/100 m2 was harmful to Kentucky bluegrass. The perennial ryegrass responded by dose-dependent growth inhibition; 30–60% in spring and 25–40% in autumn for lower and higher doses, respectively. Tall fescue responded by 50% growth inhibition independently of concentration and season. Plant physiological responses, visualized as graphs of fluorescence data, revealed the stress of Kentucky bluegrass upon high TE dose. Based on principal component analysis (PCA) analysis, three groups were distinguished: perennial ryegrass varieties from high and low TE treatments and Kentucky bluegrass varieties from high TE. TE-dependent growth reduction with no significant quality decrease benefits the environment by reducing carbon footprint machine operations (mowing). Utilizing fluorescence measurement may help to manage turf physiology.

Perennial ryegrass (Lolium perenne L.) is an important turfgrass and gramineous forage widely grown in temperate regions around the world. However, its perennial nature leads to the inevitable exposure of perennial ryegrass to various environmental stresses on a seasonal basis and from year to year. Like other plants, perennial ryegrass has evolved sophisticated mechanisms to make appropriate adjustments in growth and development in order to adapt to the stress environment at both the physiological and molecular levels. A thorough understanding of the mechanisms of perennial ryegrass response to abiotic stresses is crucial for obtaining superior stress-tolerant varieties through molecular breeding. Over the past decades, studies of perennial ryegrass at the molecular and genetic levels have revealed a lot of useful information to understand the mechanisms of perennial ryegrass adaptation to an adverse environment. Unfortunately, molecular mechanisms by which perennial ryegrass adapts to abiotic stresses have not been reviewed thus far. In this review, we summarize the recent works on the genetic and molecular mechanisms of perennial ryegrass response to the major abiotic stresses (i.e., drought, salinity, and extreme temperatures) and discuss new directions for future studies. Such knowledge will provide valuable information for molecular breeding in perennial ryegrass to improve stress resistance and promote the sustainability of agriculture and the environment.

This study was conducted in the research fields of Field Crops Department of Agriculture Faculty, Ege University, Izmir/Turkey during 2014-2016 years. Some commercial and widely used warm season turfgrasses (Cynodon dactylon cv. SR9554, Cynodon dactylon x Cynodon transvaalensis cv. Tifway-419) in addition to newly introduced turfgrasses (Paspalum vaginatum cv. Sea Spray and Zoysia japonica cv. Zenith) were chosen as plant material. To search the effect of overseeding techniques imposed in four different times (September 15, September 30, October 15 and October 30) on these selected warm season turfgrasses during fall season were aimed. For this purpose, dormancy period (day), germination speed (day), cover speed (day), fall transition (19 score) and spring transition (1-9 score) were tested in quality characteristics. Results of the study displayed that Lolium perenne L. can be practiced successfully in the ecologies like our trial location in Mediterranean ecology, in order to eliminate the problems of warm season turf grasses in the dormancy process observed in winter season. Additionally, it was concluded that optimum overseeding time should be October 15. [ABSTRACT FROM AUTHOR]

Global warming is predicted to impact many agricultural areas, which will suffer from reduced water availability. Due to precipitation changes, mild summer droughts are expected to become more frequent, even in temperate regions. For perennial ryegrass (Lolium perenne L.), an important forage grass of the Poaceae family, leaf growth is a crucial factor determining biomass accumulation and hence forage yield. Although leaf elongation has been shown to be temperature-dependent under normal conditions, the genetic regulation of leaf growth under water deficit in perennial ryegrass is poorly understood. Herein, we evaluated the response to water deprivation in a diverse panel of perennial ryegrass genotypes, employing a high-precision phenotyping platform. The study revealed phenotypic variation for growth-related traits and significant (P < 0.05) differences in leaf growth under normal conditions within the subgroups of turf and forage type cultivars. The phenotypic data was combined with genotypic variants identified using genotyping-by-sequencing to conduct a genome-wide association study (GWAS). Using GWAS, we identified DNA polymorphisms significantly associated with leaf growth reduction under water deprivation. These polymorphisms were adjacent to genes predicted to encode for phytochrome B and a MYB41 transcription factor. The result obtained in the present study will increase our understanding on the complex molecular mechanisms involved in plant growth under water deficit. Moreover, the single nucleotide polymorphism (SNP) markers identified will serve as a valuable resource in future breeding programs to select for enhanced biomass formation under mild summer drought conditions.

Understanding the differences in cool-season turfgrass responses to shade is critical for future turfgrass management and breeding for improved shade tolerance. The purpose of this study was to evaluate the shade-tolerance mechanisms of two cool-season turfgrass species in terms of turf performance, growth, and physiological characteristics. Two turfgrass species, namely, ’SupraNova’ (Poa. supina Schrad.) and ‘Lark’ (Lolium perenne L.), were subjected to 0 (CK, unshaded), 35% (LS), 70% (MS), and 92% (HS) shade, respectively. Compared with ‘Lark’, ‘SupraNova’ showed better turf quality (TQ) and turf color intensity (TCI) under shade. The total length and surface area of the roots of ‘Lark’ gradually decreased as the shade increased, while those of ‘SupraNova’ increased and then decreased with increasing shade. The chlorophyll fluorescence photochemical quenching coefficient (qP), electron transport rate (ETR), and maximum quantum yield of primary photosystem II (PSII) photochemistry (Fv/Fm) decreased significantly under HS; however, these decreases were more significant in ‘Lark’ than in ‘SupraNova’. The leaf reflectance of the two turfgrasses under shade was lower than that under CK, but the leaf reflectance of ‘Lark’ was higher than that of ‘SupraNova’ in the visible light band. The normalized difference vegetation index (NDVI) of the two grasses first decreased and then increased. The NDVI of ‘Lark’ under shade was slightly higher than that under CK. ‘SupraNova’ showed strong tolerance on the basis of malondialdehyde (MDA), hydrogen peroxide (H2O2), superoxide anion (O2·−), and ascorbic acid (AsA) contents and superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) activity. The MDA, H2O2, O2·−, and AsA contents and SOD, POD, and CAT activity (which represent indicators) changed the most under MS. Taken together, the results indicated that the adaptability of ‘SupraNova’ to shade was better than that of ‘Lark’.

Abstract Background Pyrrolizidine alkaloids (PAs) are a class of secondary metabolites that function as feeding deterrents in a range of different plant species. In perennial ryegrass (Lolium perenne L.) the only PAs that have been identified are the thesinine-rhamnoside group, which displays significant genetic variation. Homospermidine synthase (HSS) has evolved from deoxyhypusine synthase (DHS) and catalyses the first step in the PA pathway, making it a key candidate for the investigation of genes influencing observed PA trait variation. Results During PCR amplification and sequence analysis of DHS we identified two putative HSS genes in perennial ryegrass. One of the genes (LpHSS1) was absent in some perennial ryegrass plants. Thesinine-rhamnoside levels were measured using liquid chromatography coupled with mass spectrometry in a diverse association mapping population, consisting of 693 plants free of fungal endophytic symbionts. Association tests that accounted for population structure identified a significant association of absence of the LpHSS1 gene with lower levels of thesinine-rhamnoside PAs. HSS-like gene sequences were identified for other grass species of the Poaceae, including tall fescue, wheat, maize and sorghum. Conclusion HSS is situated at the crucial first step in the PA pathway making it an important candidate gene for investigation of involvement in PA phenotypic variation. In this study, PA level in perennial ryegrass was strongly associated with the presence or absence of the LpHSS1 gene. A genetic marker, developed for the presence/absence of LpHSS1, may be used for marker-assisted breeding to either lower or increase PAs in breeding populations of perennial or Italian ryegrass to investigate a potential role in the deterrence of herbivore pests. The presence of HSS-like genes in several other Poaceae species suggests that PA biosynthesis may occur in plant family members beyond perennial ryegrass and tall fescue and identifies a potential route for manipulating PA levels.

Global warming is predicted to impact many agricultural areas, which will suffer from reduced water availability. Due to precipitation changes, mild summer droughts are expected to become more frequent, even in temperate regions. For perennial ryegrass (Lolium perenne L.), an important forage grass of the Poaceae family, leaf growth is a crucial factor determining biomass accumulation and hence forage yield. Although leaf elongation has been shown to be temperature-dependent under normal conditions, the genetic regulation of leaf growth under water deficit in perennial ryegrass is poorly understood. Herein, we evaluated the response to water deprivation in a diverse panel of perennial ryegrass genotypes, employing a high-precision phenotyping platform. The study revealed phenotypic variation for growth-related traits and significant (P < 0.05) differences in leaf growth under normal conditions within the subgroups of turf and forage type cultivars. The phenotypic data was combined with genotypic variants identified using genotyping-by-sequencing to conduct a genome-wide association study (GWAS). Using GWAS, we identified DNA polymorphisms significantly associated with leaf growth reduction under water deprivation. These polymorphisms were adjacent to genes predicted to encode for phytochrome B and a MYB41 transcription factor. The result obtained in the present study will increase our understanding on the complex molecular mechanisms involved in plant growth under water deficit. Moreover, the single nucleotide polymorphism (SNP) markers identified will serve as a valuable resource in future breeding programs to select for enhanced biomass formation under mild summer drought conditions. [ABSTRACT FROM AUTHOR]

Perennial ryegrass (Lolium perenne) is the most cultivated cool-season grass worldwide with crucial roles in carbon fixation, turfgrass applications, and fodder for livestock. Lolium perenne forms a mutualism with the strictly vertically transmitted fungal endophyte, Epichloë festucae var lolii. The fungus produces alkaloids that protect the grass from herbivory, as well as conferring protection from drought and nutrient stress. The rising concentration of atmospheric CO2, a proximate cause of climatic change, is known to have many direct and indirect effects on plant growth. There is keen interest in how the nature of this plant--fungal interaction will change with climate change. Lolium perenne is an obligately outcrossing species, meaning that the genetic profile of the host is constantly being reshuffled. Meanwhile, the fungus is asexual implying both a relatively constant genetic profile and the potential for incompatible grass--fungus pairings. In this study, we used a single cultivar, "Alto", of L. perenne. Each plant was infected with one of four strains of the endophyte: AR1, AR37, NEA2, and Lp19 (the "common strain"). We outcrossed the Alto mothers with pollen from a number of individuals from different ryegrass cultivars to create more genetic diversity in the hosts. We collected seed such that we had replicate maternal half-sib families. Seed from each family was randomly allocated into the two levels of the CO2 treatment, 400 and 800 ppm. Elevated CO2 resulted in an c. 18% increase in plant biomass. AR37 produced higher fungal concentrations than other strains; NEA2 produced the lowest fungal concentrations. We did not find evidence of genetic incompatibility between the host plants and the fungal strains. We conducted untargeted metabolomics and quantitative proteomics to investigate the grass-fungus interactions between and within family and treatment groups. We identified a number of changes in both the proteome and metabalome. Taken together, our data set provides new understanding into the intricacy of the interaction between endophyte and host from multiple molecular levels and suggests opportunity to promote plant robustness and survivability in rising CO2 environmental conditions through application of bioprotective epichloid strains. [ABSTRACT FROM AUTHOR]

Greenhouse soil culture experiments were conducted to investigate the phytoextraction of uranium from topsoil by Lolium perenne L. The effects of addition of CaO2，Aspergillus niger fermentation broth and their combination on some of physiological characteristics of Lolium perenne L. and enhancement of uranium phytoextraction were investigated. The results showed that the separate application of high dosed A niger fermentation broth had a stimulative effect on Lolium perenne L. growth whereas the separate application of high dosed CaCb，the joint application of high dosed CaO2 and A niger fermentation broth both gave an inhibitive effect. Furthermore, all the treatments resulted in an increased accumulation of soluble protein in Lolium perenne L. leaves, among which the separate addition of 40 mL/kg fermentation broth generated the highest content， increasing by 511. 11 % compared to the control. The application of A niger fermentation alone led to the decreases in superoxide dismutase(SOD) activity and malondialdehyde(MDA) contents in Lolium perenne L. leaves, while the separate application of high dosed CaO2，joint application of high dosed Ca()2 and A niger fermentation broth both caused a reveres effect. Moreover, the uranium concentration in the soil solution and uranium phytoextraction raised in all the treatments, in which the combined application at 1 g/kg CaCb and 20 mL/kg fermentation broth showed the best effect ； uranium content in the ash of Lolium perenne L. above ground increased by 622, 80 %，and the total accumulation of uranium increased by 483. 65 % against the control. [ABSTRACT FROM AUTHOR]

The objective of this study was to compare the grazing efficiency of 30 perennial ryegrass varieties, differing in ploidy and heading date. Plots were grazed by lactating dairy cows and managed under a rotational grazing system with 19 grazing events occurring over two years. Pre‐grazing and post‐grazing compressed sward heights were measured with a rising plate meter. A mixed model was used to predict the post‐grazing sward height of each variety based on year, grazing event, block and pre‐grazing sward height. Residual grazed height (RGH) was derived as the difference between the actual and predicted post‐grazing sward height and was used as the measure of grazing efficiency. Negative RGH values indicated that the actual herbage removed was greater than that predicted and so indicated a superior grazing efficiency. Varieties differed in their level of grazing efficiency (p <.001), with RGH values ranging from −0.38 to +0.34 cm. Tetraploid varieties exhibited significantly greater grazing efficiency performance than diploids (p <.001), with average RGH values of −0.13 and +0.13 cm respectively. A significant difference in grazing efficiency was found among recommended perennial ryegrass varieties that are not being recorded by mechanically harvested simulated grazing protocols. A variety reappraisal that included grazing efficiency could identify varieties capable of improving on‐farm livestock productivity from grass. [ABSTRACT FROM AUTHOR]

Physical fractionation of a municipal solid waste compost was performed by a dry sieving process to obtain two particle size fractions (> 1.6 mm and 0.8–1.6 mm). The compost with the two particle sizes and the whole unfractionated compost were applied to field soil, and the effect of different size fractions of compost on the growth and physiological characteristics of Lolium perenne L. were investigated. The results showed that the plant height and shoot biomass of L. perenne were higher in the treatments with the whole compost and > 1.6 mm size fraction compared with the control throughout the growing season, but the difference between treatments decreased gradually. The chlorophyll content in these two treatments was also higher than that in the control. The biomass, chlorophyll b, and total chlorophyll content of the second harvest were 23.8%, 82.1%, and 13.9%, respectively, higher in the > 1.6 mm size fraction treatment than in the control. In addition, L. perenne had a dark green color and uniform plants in the > 1.6 mm fraction treatment, which scored the highest in the comprehensive evaluation of turf quality. Plants treated with the coarse fraction of > 1.6 mm showed a strong photosynthetic capacity and maintained a high protective enzyme activity and proline content to improve stress resistance. [ABSTRACT FROM AUTHOR]