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Historically, white clover (Trifolium repens) seed was included in turfgrass seed mixtures to provide biodiversity and nitrogen (N) to lawns. White clover dicultures have been studied recently for inclusion in both warm- and cool-season turfgrasses, with the goals of reducing fertilizer applications and providing pollinator forage in lawns; however, other clovers have not been as widely researched in turfgrass. The objectives of this study were to evaluate 1) if white, strawberry (T. fragiferum), crimson (T. incarnatum), and rose (T. hirtum) clovers can persist in dicultures with Kentucky bluegrass (Poa pratensis); 2) if clover inclusion in dicultures impacts broadleaf weed cover; and 3) if low levels of N fertilization impact clover persistence or quality of clover-bluegrass dicultures. Kentucky bluegrass was grown as a monoculture or as a diculture with each of the four clover species. Each mono- or diculture was then treated with a low rate of N fertilizer (48.8 kgha-1 N) or no N fertilizer to determine quality and percentage of grass, clover, or weed and bare-soil cover. Dicultures contained similar or less weed and bare-soil cover, and maintained similar or greater quality compared with bluegrass monocultures, indicating clover and Kentucky bluegrass dicultures are suitable alternatives to Kentucky bluegrass monoculture lawns, and can potentially lead to reduced fertilizer and pesticide requirements. Fertilizer generally had no effect on cover, likely because of the low rates of N applied. [ABSTRACT FROM AUTHOR]

In the experimental field of the Research Institute of Mountain Stockbreeding and AgricultureTroyan during the period 2020-2022, the following meadow legume crops were studied: bird’s foot trefoil (Lotus corniculatus L.), hybrid clover (Trifolium hibridum L.), alfalfa (Medicago sativa L.), red clover (Trifolium pratense L.) and white clover (Trifolium repens L.). The purpose of the present research is to make a statistical analysis based on average data on yield, morphological features and quality, and determine dependencies between them. High correlations were found between plant height and crude fiber content (r = 0.88); crude fiber and the relative proportion of legumes in the grass stand (r = 0.77); acid detergent fibers and cellulose content (r = 0.92). These results make it possible to derive regression dependencies between them, which are represented by linear equations and coefficients of determination. [ABSTRACT FROM AUTHOR]

Aims: To develop a methodology to study uptake and redistribution by plants of NH4+ from deep soil, applying it to investigate deep root N uptake by cultivated grassland species. Methods: A slow-release 15NH4+ label adsorbed to clinoptilolite was placed into soil (depth 42 cm) well below the densest root zone in well-established monospecific stands of five grass and two clover species. Species showing a variety of deep rooting patterns, N acquisition strategy, forage qualities, and persistence in hemiboreal conditions were chosen. The label was placed in early spring and tracked throughout one or two growing seasons in two repeated experiments. Results: After two growing seasons ~ 90% of the label was tracked in the soil and harvested herbage of grasses, less in clovers. Deep N uptake was limited in spring, increased during mid-season, and was strongest in autumn in all species, despite lower herbage yield in autumn. Species differed in ability to recover and maintain 15N in the soil–plant system. In one growing season, Lolium perenne L., Phleum pratense L., Schedonorus pratensis (Huds.) P.Beauv. and Schedonorus arundinaceus (Schreb.) Dumort herbage recovered ~ 65% of the label, Poa pratensis L. 54%, and Trifolium pratense L. and Trifolium repens L. 36–48%. Label transport to topsoil was observed, mainly attributable to plant nutrient redistribution rather than physical diffusion. Conclusions: The innovative slow-release 15N label enabled tracing species differences and seasonal changes in uptake of NH4+ from deep soil. Among the tall-growing grasses, growth vigor appeared as important for deep N uptake as expected root depth. [ABSTRACT FROM AUTHOR]

The objective of this study was to quantify the farm gate nitrogen (N) offset potential of perennial ryegrass (Lolium perenne L.; PRG) white clover (Trifolium repens L.; WC) swards by comparing the herbage and milk production from dairy farmlets that were simulations of full farming systems. A study was established where 120 cows were randomly assigned to 4 farmlets of 10.9 ha (stocking rate: 2.75 cow/ha), composed of 20 paddocks each. Cows were fed 526 kg of DM of concentrate on average each year. The 4 grazing treatments were PRG-only at 150 or 250 kg of N/ha and PRG-WC at 150 or 250 kg of N/ha. Cows remained in their treatment group for an entire grazing season and were re-randomized as they calved across treatments each year. As cows calved in the spring as standard practice in Ireland, they were rotationally grazed from early February both day and night (weather permitting) to mid-November, to a target postgrazing sward height of 4.0 cm. Mean sward WC content was 18.1% and 15.4% for the 150 and 250 kg of N/ha PRG-WC treatments, respectively over the 3-yr period. When WC was included, lowering the N rate did not reduce pregrazing yield, pregrazing height, or herbage removed, but those factors decreased significantly when WC was absent. Total annual herbage DM production was 13,771, 15,242, 14,721, and 15,667 kg of DM/ha for PRG-only swards receiving 150 or 250 kg of N/ha and PRG-WC swards receiving 150 or 250 kg of N/ha, respectively. In addition, when WC was present, compressed postgrazing sward heights were lower (4.10 vs. 4.21 cm) and herbage allowance (approximately 17 kg/cow feed allocation per cow per day) higher than the high-N control (+ 0.7 kg of DM/cow per day). There was a significant increase in milk production, both per cow and per hectare, when WC was included in PRG swards. Over the 3-yr study, cows grazing PRG-WC had greater milk (+304 kg) and milk solids (+31 kg of fat + protein) yields than cows grazing PRG-only swards. This significant increase in milk production suggests that the inclusion of WC in grazing systems can be effectively used to increase milk production per cow and per hectare and help offset nitrogen use. This result shows the potential to increase farm gate N use efficiency and reduce the N surplus compared with PRG-dominant sward grazing systems receiving 250 kg of N/ha, without negatively affecting milk solids yield or herbage production, thus increasing farm profit by €478/ha. [ABSTRACT FROM AUTHOR]

Context: Tagasaste (Cytisus proliferus), a fast-growing leguminous tree, has potential to supplement pasture production in steep-hill country and to increase pasture resilience. Aims: In the companion paper, we quantified tagasaste production characteristics. Here, we determine the effect of proximity of 10-year-old tagasaste trees on productivity of eight pasture species including grasses (perennial ryegrass, Lolium perenne ; cocksfoot, Dactylis glomerata ; prairie grass, Bromus willdenowii ; microlaena, Microlaena stipoides), perennial legumes (white clover, Trifolium repens ; red clover, T. pratense ; lotus, Lotus pedunculatus), and an annual legume (subterranean clover, T. subterraneum). Methods: A site was established in the East Coast region of the North Island of New Zealand on steep-hill country (>20° slope). Herbage production, nutritive value and survival of pasture species established as spaced transplants were measured over 3 years. Results: Cocksfoot had high survival, herbage production and metabolisable energy content but was negatively affected by proximity to tagasaste. Microlaena was not significantly affected by proximity to tagasaste; however, it was much less productive and had lower nutritive values than the other grasses. Only 40% of perennial ryegrass transplants survived 3 years, and survival of perennial legumes was negligible. Subterranean clover was able to set seed in the open and in shade. Conclusions: Cocksfoot was the most productive grass species, and microlaena was least affected by proximity to tagasaste. Given the poor persistence of perennial clovers, annual clovers may be better suited to a tagasaste silvopasture on steep, dry hillsides. Implications: Mixtures of cocksfoot and subterranean clover may be well suited to summer-dry hillsides, between and under trees in a tagasaste silvopasture. Microlaena may provide some forage and can maintain groundcover despite shade. Growth and survival of eight pasture species in proximity to the forage shrub tagasaste were quantified in drought-prone hill country. Cocksfoot and subterranean clover were highly productive only in lightly shaded areas, whereas microlaena, although less productive than other grasses, was not significantly affected by shade treatment, and perennial legumes showed negligible survival. Cocksfoot and subterranean clover could be established between trees in a tagasaste silvopasture, with naturalised microlaena maintained beneath the canopy to provide groundcover. [ABSTRACT FROM AUTHOR]

Context: Rock phosphate reserves are decreasing, and requirements to mitigate environmental impacts of farming soils with excess phosphorus (P) are increasing. Aims: White clover is an allotetraploid hybrid between Trifolium pallescens and T. occidentale. Understanding the P response characteristics of these progenitor species will allow selection of germplasm for development of synthetic white clovers with improved phosphorus-use efficiency (PUE). Methods: Shoot and root weights and P nutrition characteristics were compared for three Trifolium pallescens , six T. occidentale accessions, and a white clover cultivar in a glasshouse experiment using a low P soil amended with five rates of P. Key results: White clover had the highest and most P responsive shoot and root dry weights (DW), and T. pallescens was least responsive to P. In the highest P treatment, T. pallescens had the highest shoot and root %P and the lowest shoot DW:total plant P ratio. There was significant variation among progenitor accessions. Spanish accessions of T. occidentale had comparable shoot DW to white clover and higher PUE. Traits of T. pallescens indicated strong adaptation to low P but low productivity, while traits of T. occidentale were more aligned with the white clover cultivar. Conclusions: The substantial variation in P nutrition characteristics within the progenitor species of white clover could be exploited in breeding programs. Implications: Comparing the P responses of a wider range of progenitor accessions could inform breeding to improve white clover's low soil P tolerance through development of synthetic white clovers. There are strong ethical, environmental, and economic reasons for increasing the phosphate-use efficiency of white clover, a natural hybrid between Trifolium pallescens and T. occidentale. White clover has poor phosphate-use efficiency, but we found significant variation for relevant characteristics between the two parental species and among populations within each species. Developing cultivars using superior populations of the parental species could be a very effective breeding strategy for increasing phosphate-use efficiency of white clover. [ABSTRACT FROM AUTHOR]

While shaping of plant microbiome composition through 'host filtering' is well documented in legume–rhizobium symbioses, it is less clear to what extent different varieties and genotypes of the same plant species differentially influence symbiont community diversity and composition. Here, we compared how clover host varieties and genotypes affect the structure of Rhizobium populations in root nodules under conventional field and controlled greenhouse conditions. We first grew four Trifolium repens (white clover) F2 crosses and one variety in a conventional field trial and compared differences in root nodule Rhizobium leguminosarum symbiovar trifolii (Rlt) genotype diversity using high‐throughput amplicon sequencing of chromosomal housekeeping (rpoB and recA) genes and auxiliary plasmid‐borne symbiosis genes (nodA and nodD). We found that Rlt nodule diversities significantly differed between clover crosses, potentially due to host filtering. However, variance in Rlt diversity largely overlapped between crosses and was also explained by the spatial distribution of plants in the field, indicative of the role of local environmental conditions for nodule diversity. To test the effect of host filtering, we conducted a controlled greenhouse trial with a diverse Rlt inoculum and several host genotypes. We found that different clover varieties and genotypes of the same variety selected for significantly different Rlt nodule communities and that the strength of host filtering (deviation from the initial Rhizobium inoculant composition) was positively correlated with the efficiency of symbiosis (rate of plant greenness colouration). Together, our results suggest that selection by host genotype and local growth conditions jointly influence white clover Rlt nodule diversity and community composition. [ABSTRACT FROM AUTHOR]

Context: High-quality, summer-active pastures could improve meat production in south-eastern Australia by facilitating livestock finishing over summer, with legumes critical for enhancing the nutritive value of pasture mixes. Available legumes vary in their ability to withstand moisture stress and grazing. Aims: We aimed to identify legumes suitable for a summer–autumn finishing system. Methods: We tested pure swards of 12 cultivars across eight legume species in replicated small-plot experiments at Goulburn and Bombala, New South Wales, assessing productivity, persistence and warm-season nutritive characteristics over 2–3 years. Key results: Lucerne (Medicago sativa) was clearly the most productive species during summer and outperformed the clovers (Trifolium spp.) in terms of persistence and productivity throughout most of the experimental period at both sites, except during autumn 2021 after high rainfall in March. Caucasian clover (T. ambiguum) was also highly persistent at both sites. Talish clover (T. tumens) and strawberry clover (T. fragiferum) were more persistent than white clover (T. repens) and red clover (T. pratense). White clover recovered strongly under high rainfall after drought, whereas red clover established rapidly but showed less capacity for post-drought recovery. Hybrid Caucasian × white clover was the least productive legume. Alternative clover species sometimes had slightly lower values of nutritive characteristics than white clover; red clover sometimes had distinctly lower values. Conclusions: Lucerne performed best but several clovers were also productive, persistent and of high nutritive value over the summer–autumn period. Implications: Talish, Caucasian and strawberry clovers warrant further investigation for inclusion in summer-active pastures in south-eastern Australia. Profitability of livestock production over summer–autumn in the temperate environment of south-eastern Australia could be improved by including legumes in pastures that are persistent, productive and of high nutritive value. Evaluation of a range of legume species and cultivars showed that lucerne remained the most reliably productive warm-season option where soil conditions support it. Talish, Caucasian and strawberry clovers were persistent and of high nutritive value, warranting further evaluation in special-purpose warm-season pastures. [ABSTRACT FROM AUTHOR]

Context: Improving the stability of legumes in grasslands in the face of variable seasonal conditions is key to mitigating risks posed by drought. Aims: We assessed the persistence of a range of legume species and cultivars in order to inform legume choice for pasture improvement and identify priority species for further development. Methods: Twenty field experiments in four series were conducted at sites with contrasting seasonal and soil characteristics in the 'high-rainfall' (560–920 mm long-term average) Tablelands and Monaro regions of New South Wales, Australia. Legumes were grown as pure swards and assessed periodically for seedling density, plant frequency and dry matter for up to 5 years. Key results: Legume dry matter production was positively correlated with plant frequency. However, most legumes persisted poorly at most sites, particularly on soils of lower fertility. Subterranean clover (Trifolium subterraneum) cv. Goulburn was the best performing cultivar of that species across sites on the Southern Tablelands and Monaro. Yellow serradella (Ornithopus compressus) cvv. Avila and Yellotas showed promising persistence, particularly under drought conditions. White clover (T. repens) was the most broadly adapted of the perennial legumes across a range of soils, but persistence was still inadequate at many sites. Lucerne (Medicago sativa) was approximately twice as productive as the next-most productive species when soil conditions suited its growth, but it failed to persist on acidic, low-fertility soils. Conclusions: Serradella species (yellow and French, O. sativus) and white clover, in conjunction with subterranean clover, offer the best near-term prospects for diversifying legume productivity and resilience under variable seasonal conditions in tableland environments. Implications: An increased focus on phenology and seed characteristics is suggested to improve the persistence of annual and facultative perennial legume species in grasslands. Serradella and white clover are identified as the highest priorities for cultivar development for tableland environments of south-eastern Australia. This study evaluated the stability and persistence of a range of legume species and cultivars to identify viable options for grasslands of south-eastern Australia. Yellow and French serradella, white clover and subterranean clover were identified as priority species because they are already, or are close to being, viable options for use in grasslands. An increased focus on phenology and seed characteristics is suggested to improve the persistence of white clover and serradella in grasslands. [ABSTRACT FROM AUTHOR]

The long-term influence of several living mulches on apple tree growth, nutrient status, yield, and fruit quality concerning the year of cover crop sowing in tree rows was evaluated in the Lower Silesia region in the southwestern part of Poland. The estimation was conducted in six apple tree 'Ligol' populations differentiated by the rootstock: M.26, M.9, P 60, P 2, P 16, and P 22. In experiment no. 1, one-year-old nursery stock was planted, and perennial living mulches were sown: colonial bent grass (Agrostis vulgaris With.) and white clover (Trifolium repens L.) in the same year and blue fescue (Festuca ovina L.) in the following year. In experiment no. 2, which involved two-year-old stock, the sowing of blue fescue was delayed until the second, third, fourth, and fifth years following orchard planting. The presence of the cover crop significantly affected young tree growth when one-year-old trees were planted. The sowing of the living mulch in the first or the second year after tree planting led to a significant reduction in the cumulative yield obtained from the young trees. The living mulch improved the red coloration of the fruit skin in the young orchard, but it caused a reduction in the mean fruit weight and size. However, it also contributed to decreased nitrogen concentration in the leaves of the apple trees, the tree tolerance to living mulch increased as the orchard aged. A choice of semidwarf rootstock, postponed sowing of cover crop, and high-quality nursery stock were recognized as the most important factors for fostering apple tree tolerance to living mulches in tree rows. [ABSTRACT FROM AUTHOR]

This experiment investigated the variation in enteric methane production and associated gas exchange parameters, nutrient digestibility, rumen fermentation, and rumen microbiome when a range of silages based on different forage types (grass or clover), and different species within the 2 types, were fed as the sole feed to heifers. Three grass species (perennial ryegrass, festulolium, and tall fescue) and 2 clover species (red clover and white clover) were included. Perennial ryegrass was harvested at 2 maturity stages in the primary growth, white clover was harvested once in the primary growth, and 4 cuts of festulolium and tall fescue and 3 cuts of red clover were harvested during the growing season, giving 14 different silage batches in total. Sixteen Holstein heifers 16 to 21 mo old and 2 to 5 mo in pregnancy were fed the silages ad libitum as the sole feed in an incomplete crossover design. Each silage was fed to 4 heifers, except for the 2 perennial ryegrass silages, which were fed to 8 heifers; in total 64 observations. The CH 4 production was measured for 3 d in respiration chambers. Heifers fed clover silages had higher dry matter intake (DMI) compared with heifers fed grass silages, and heifers fed tall fescue silages had the numerically the lowest DMI. Compared with grass silages, feeding clover silages led to higher crude protein digestibility but lower neutral detergent fiber (NDF) digestibility. Rumen pH was higher in heifers fed clover silages compared with those fed grass silages. Based on composition analysis, the rumen microbiota of the heifers clustered clearly according to forage type and species. More specifically, 7 of the 34 dominating rumen bacterial genus-level groups showed higher relative abundances for the clover silages, whereas 7 genus-level groups showed higher abundances for the grass silages. Methane yield was higher for heifers fed grass silages than for those fed clover silages when methane production was related to dry matter and digestible organic matter intake, whereas the opposite was seen when related to NDF digestion. The gross energy lost as methane (CH 4 conversion factor, %) reduced from 7.5% to 6.7%, equivalent to an 11% reduction. The present study gives the outlines for choosing the optimal forage type and forage species with respect to nutrient digestibility and enteric methane emission in ruminants. [ABSTRACT FROM AUTHOR]

Background: The implementation of polyphytic pastures composed of grasses and legumes is an important component of agricultural systems in temperate zones, since grazing pastures which can reduce feed costs--are a viable option for small-scale dairy systems (SSDS). Objective: To evaluate the continuous grazing of dairy cows in Festulolium pastures associated with annual and perennial ryegrass and with clover in two farmrs. Methodology: Two experiments were carried out. The first experiment was established in the municipality of Almoloya of Juárez using eight cows that were divided into two groups of four; the cows grazed on two pastures with Festulolium associated with annual ryegrass and they were fed with 3.6 kg DM/cow/day of commercial concentrate, for 16 weeks. The second experiment was carried out in the Northwest of State of Mexico; six multiparous cows grazed on two pastures, under a cross over design arrangement; one pasture features Festulolium cv Spring Green and the other, annual ryegrass. Milk and body condition ere measured every 3 and 12 d, respectively. Variables from both experiments were analyzed using a split-plot experimental design. Results: Neither experiment recorded significant differences for the net accumulation of forage, the height of the pastures, and their chemical composition (P=0.05). No significant differences between treatments (P=0.05) were recorded regarding the yields and chemical composition of the milk. Study Limitations/Implications: The study of mixed pastures can be an alternative for feeding grazing cows, helping to reduce costs in SSDS. Findings/Conclusions: Festulolium/annual ryegrass pastures with white clover are a viable forage alternative for small-scale dairy systems. [ABSTRACT FROM AUTHOR]

Interseeding annual warm‐season grasses may increase forage and pasture productivity. From 2017 to 2019, we conducted a grazing experiment that examined smooth bromegrass (Bromus inermis Leyss.) pasture responses to interseeding sorghum‐sudangrass [Sorghum bicolor (L.) Moench × S. bicolor (L.) Moench ssp. drummondii (Nees ex Steud.) de Wet & Harlan]. The experiment had a split‐plot design with six main plots each containing two, 0.60‐ha pasture subplots (i.e., 12 total subplots). The six main plots included three replications each of two pasture types: (A) nitrogen (N)‐fertilized smooth bromegrass (FERT) and (B) mixed legume‐smooth bromegrass [LEG; alfalfa (Medicago sativa L.), red clover (Trifolium repens L.), and birdsfoot trefoil (Lotus corniculatus L.)]. The subplots included sorghum‐sudangrass interseeded and unseeded control treatments. Each pasture subplot, which supported two steers (Bos taurus) from spring through summer, contained six, 0.10‐ha sub‐subplots for rotational stocking. Sorghum‐sudangrass was interseeded after stocking cycle 2 in two of the sub‐subplots in the interseeded subplot each year. Vegetation responses were evaluated in these sub‐subplots and in two adjacent sub‐subplots in the unseeded control subplot. Across years, sampling dates, and subplot treatments, the LEG main plots supported 7% greater forage biomass (2743 ± 102 kg ha−1) and six more grazing days than the FERT main plots (2552 ± 111 kg ha−1). Sorghum‐sudangrass interseeded sub‐subplots, however, had 36% greater forage biomass than unseeded sub‐subplots pre‐grazing in stocking cycle 5. To optimize forage biomass, producers should fertilize in early spring or maintain legumes in smooth bromegrass pastures. Interseeding sorghum‐sudangrass provides an option to increase late‐summer forage biomass. Core Ideas: Nitrogen (N)‐fertilized and mixed legume‐smooth bromegrass pastures produced the same amount of perennial grass biomass.Mixed legume‐smooth bromegrass pastures had more total forage and grazing days than N‐fertilized pastures.Interseeding sorghum‐sudangrass increased late‐summer forage and reduced biomass of weedy grasses such as foxtail.Years with more spring or summer precipitation, such as 2017 and 2018, had greater sorghum‐sudangrass biomass.Earlier seeding into shorter stubble in spring would likely improve sorghum‐sudangrass establishment in dry years. [ABSTRACT FROM AUTHOR]

The ability of a species to colonize new geographical areas is closely related to its morphological response to environmental gradients. Previous studies compared native and alien invasive species in their ability to modify their morphology in reaction to climatic and edaphic factors; however, taxonomically close species have been scarcely analyzed. In this study, morphological variability patterns associated with abiotic factors were evaluated in Trifolium polymorphum, a native species distributed from southern Brazil to northern Patagonia, and Trifolium repens, a species introduced as an important forage crop and naturalized in diverse environments of southern South America. A morphometric study was carried out using herbarium specimens that were then georeferenced to obtain environmental and distributional data. Morphological traits along abiotic and geographical gradients were analyzed, predictive distribution and current and future niches were modelled. Our results showed that leaf morphology of T. repens responds to precipitation and temperature factors, which could explain its invasive behavior in a wide range of environments. Morphological variability of the native T. polymorphum presented a low association with abiotic factors, suggesting possible difficulties in adapting to future environmental changes. Ecological niche modelling analysis showed several overlap areas between species in the current model and a greater expansion of the distribution range of the invasive species in future climate change scenarios. [ABSTRACT FROM AUTHOR]

Incorporating plantain with perennial ryegrass and white clover (RGWC) can improve the quality and quantity of grazing pastures; however, the sowing rate could affect the persistence of plantain, pasture yield, and nutritive value in different seasons. The objective of this study was to evaluate the effect of increasing sowing rates of plantain when established with RGWC on the dry matter (DM) yield, botanical composition, nutritive value, and bioactive compounds of the pasture over the first two years after sowing; and to determine the relationship between plantain content and nutritive characteristics in different seasons. The pasture treatments were RGWC, RGWC + low plantain rate (PLL), RGWC + medium plantain rate (PLM), and RGWC + high plantain rate (PLH). The results showed that annual DM yield was similar between treatments. The average plantain content (including leaves and reproductive stem) was 32, 44, and 48% in PLL, PLM, and PLH, respectively. The plantain composition increased in the first 15 months, then declined rapidly to about 20–30% at day 705 after sowing. Compared with RGWC, the plantain-RGWC pastures (PLL, PLM, PLH) had a higher content of organic matter digestibility (OMD), ash, starch, non-structural carbohydrates (NSC), P, S, Ca, Mg, Na, Cl, Zn, B, Co, aucubin, acteoside, and catalpol, while they contained a lower composition of DM%, acid detergent fibre (ADF), neutral detergent fibre (NDF), crude fat (CF), Fe, and Mn. These differences were linearly associated with the content of plantain leaves in the pasture and were higher in summer and autumn than in spring. In conclusion, incorporating plantain into the RGWC pasture can improve herbage nutritive quality, thus potentially increasing farm productivity and environmental benefits. However, further work is required to investigate management interventions to sustain plantain content beyond two years from sowing. [ABSTRACT FROM AUTHOR]

Purpose : Nitrogen (N) transfer from white clover (Trifolium repens cv.) to ryegrass (Lolium perenne cv.) has the potential to meet ryegrass N requirements. This study aimed to quantify N transfer in a mixed pasture and investigate the influence of the microbial community and land management on N transfer. Methods: Split root 15N-labelling of clover quantified N transfer to ryegrass via exudation, microbial assimilation, decomposition, defoliation and soil biota. Incorporation into the microbial protein pool was determined using compound-specific 15N-stable isotope probing approaches. Results: N transfer to ryegrass and soil microbial protein in the model system was relatively small, with one-third arising from root exudation. N transfer to ryegrass increased with no microbial competition but soil microbes also increased N transfer via shoot decomposition. Addition of mycorrhizal fungi did not alter N transfer, due to the source-sink nature of this pathway, whilst weevil grazing on roots decreased microbial N transfer. N transfer was bidirectional, and comparable on a short-term scale. Conclusions: N transfer was low in a model young pasture established from soil from a permanent grassland with long-term N fertilisation. Root exudation and decomposition were major N transfer pathways. N transfer was influenced by soil biota (weevils, mycorrhizae) and land management (e.g. grazing). Previous land management and the role of the microbial community in N transfer must be considered when determining the potential for N transfer to ryegrass. [ABSTRACT FROM AUTHOR]

Soil aggregate composition is an important factor that affects soil organic carbon (SOC) content. Earthworms can greatly affect soil aggregate composition. However, the effects of earthworms' activities on SOC content in soil aggregates and the stability of these compounds was not clear. To reveal the mechanism of earthworms impacts on soil carbon stock, different earthworms densities were set in soil columns planted with clovers (Trifolium repens L.). We then analyzed the relationship that earthworms had with soil physicochemical properties and clover plant growth. Earthworms increased the large (17.5%–35.6%) and medium aggregate content (0.6%–9.79%) and decreased the microaggregates content (19.8%–29%) of the surface soil. Soil aggregates in medium density treatment were more stable than those in others. Both the mean mass diameter and geometric mean diameter of soil aggregates increased with the densities of earthworms. The average SOC content in large‐, medium‐, and microaggregates were 5.5, 4.2, and 4.2 g kg−1 respectively in soils seeded with earthworms. There was a significant correlation between soil organic carbon content and macroaggregate organic carbon content (R2 = 0.623, p < 0.05). The root characteristic values (root length, surface area, diameter, and biomass) of earthworm‐treated clover‐planted soils were higher than those of control. Clover root indices were positively correlated with the soil organic carbon content and soil aggregates. Earthworms altered the soil aggregate content and enhanced soil organic carbon storage, and thus promoted the development of vegetation roots. This study provides scientific support for a deeper understanding of the mechanisms of earthworms in soil carbon storage. [ABSTRACT FROM AUTHOR]

The addition of self‐regenerating annual legumes into permanent pastures can benefit rapid forage growth in early spring, leading to increased pasture production and animal live weight gain (LWG). The objective of this 2‐year grazing study was to evaluate the effects of balansa clover (Trifolium michelianum) and subterranean clover (Trifolium subterraneum) on pasture and animal production in an irrigated dairy system in western Oregon, USA. Study results showed that balansa clover has a high potential to increase legume content of establishing pastures in early spring. Legume content of pastures sown with annual legumes increased by 25.3% in early spring compared to pastures sown without annual legumes. However, no significant increase in legume content was observed past the initial year of establishment. The persistence of balansa clover and subterranean clover was low in 2021, at <1% of the botanical composition. The overall benefits of balansa clover in early spring in 2020 were offset by reduced perennial forbs, white clover (Trifolium repens) and chicory (Cichorium intybus), in paddocks that were sown with annual legumes. However, this did not negatively affect the LWGs of heifers. This study found no significant difference between pastures sown with and without annual clovers pastures on dry matter production and animal production. Balansa clover was competitive in the establishment year; however, further research into improving its persistence past establishment is warranted. [ABSTRACT FROM AUTHOR]

Grapevine leafroll disease (GLD) affects grapevines worldwide. The primary causal agent of GLD is grapevine leafroll-associated virus 3 (GLRaV-3), which spreads to uninfected grapevines via mealybugs and soft-scale insects. Pseudococcus calceolariae (Hemiptera: Pseudococcidae) is a mealybug vector of GLRaV-3 in New Zealand. P. calceolariae also colonizes clovers (Trifolium spp.) growing naturally as vineyard ground cover. Separating mealybug from GLRaV-3 grapevine host could be enhanced by a trap plant: an alternative host attractive to and retentive of the target pest. We evaluated the association between P. calceolariae and ‘Grasslands Huia’ white clover (GHWC). GHWC seed was sown under grapevines in a commercial vineyard (14 × 0.4 ha plots); the control was under-vine herbicide use (7 × 0.4 ha plots, where only few Trifolium spp. plants grew). After 2 years, GHWC cover peaked at 40% mealybug infestation in 2019. From 2018 to 2021, P. calceolariae detection and abundance on GHWC was significantly higher than plants from the control plots. There was no treatment effect for mealybug infestation of grapevine leaves nor of GLRaV-3 incidence, independent of vintage. A glasshouse trial found no transmission of GLRaV-3 by P. calceolariae to any of 256 plants among five clover cultivars tested (Trifolium spp.), including GHWC; mealybug transmitted GLRaV-3 to 35 of 107 Nicotiana benthamiana plants. The results showed that in the 5-year period, added GHWC did not decouple P. calceolariae from the grapevine to reduce GLRaV-3 incidence, but rapid colonization of GHWC by mealybug and the lack of GLRaV-3 transmission to GHWC are encouraging. Further evaluation is needed to assess whether plant biodiversity can benefit a GLRaV-3 ecological management objective. [ABSTRACT FROM AUTHOR]

Clover yellow mosaic virus (ClYMV) is reported for the first time in two cultivars of ornamental verbena (Verbena X hybrid) from Christchurch in New Zealand. Sequencing of a ~ 500 bp fragment of the 8 KDa triple gene block and coat protein partial genes indicated the NZ isolates were closely related to ClYMV from verbena in the UK and Poland and more distantly to isolates from clover in Australia and Japan. ClYMV has been intercepted in quarantine in tulips and detected in white clover in Auckland; the verbena isolates may represent a separate incursion into NZ. [ABSTRACT FROM AUTHOR]

The production and pest susceptibility of eight clover cultivars were compared over two years in the pasture at two contrasting sites: a rain-fed Waikato cattle-grazed pasture and an irrigated Canterbury dairy pasture. The cultivars were four white clovers (Trifolium repens L.) (Grasslands Kopu II, Grasslands Mainstay, SF Quest and Weka), two red clovers (T. pratense L.) (Grasslands Relish, Rubitas), a strawberry clover (T. fragiferum) (Palestine) and a white clover × Caucasian (T. ambiguum M. Bieb.) hybrid (Aberlasting). Grasslands Relish outperformed all other clovers and was associated with the fewest root-damaging nematodes. Both red clovers were less susceptible to insect pests than the white clovers, but Rubitas was vulnerable to root pathogens in Waikato. The poorest performing cultivar was Aberlasting, which was the most susceptible cultivar in all pest and disease measures. The white clovers and strawberry clover performed similarly across most measures. An assay using soils from each site showed that clover seedlings grown in pasteurised Waikato soil were almost ten times larger than those in the non-pasteurised soil whereas pasteurisation made no significant difference with the Canterbury soil. This study demonstrated that root health was a major factor in the contrasting site and cultivar differences in the early years of production. [ABSTRACT FROM AUTHOR]

This review covers a comprehensive overview of the phytoconstituents and bioactivities reported to date for clover honeys produced from various Trifolium spp. against the backdrop of a more general discussion of the chemistry and bioactivity of these important agricultural species. While research into the phytochemical composition of various honeys and their associated bioactivities is growing, this review demonstrates that the literature to date has seen only a limited number of studies on clover honeys. Surprisingly, there appear to be no comparative data on the concentration of flavonoids in general or isoflavonoids specifically in different clover honeys, although the latter have been identified as a main group of bioactive compounds in red clover plants. Based on the findings of this review, the presence of phytoestrogenic isoflavonoids (e.g., formononetin, biochanin A, genistein, daidzein, glycitein) in clover plants and, by extension, in clover honeys should be further investigated, specifically of clover species outside the three popular perennial clovers (red, white and alsike clovers) to exploit new opportunities of potential benefit to both the pharmaceutical and apiculture industries. [ABSTRACT FROM AUTHOR]

This study was carried out to determine chemical composition, relative feed values (RFV), in vitro gas production (IVGP), metabolisable energy (ME), organic matter digestibility (OMD) of 21 different legume forages. Species examined, crude protein (CP) ration of legume forages was 12.75-24.96%, ADF 23.63-39.53%, NDF 36.29-68.54%, RFV 109.96-179.20, IVGP 38.81-50.89 ml, ME 8.52-10.45 MJ kg-1 DM, OMD 56.10-68.54% was in range. Vicia pannonica Crantz. and Vicia narbonensis L. stand out in terms of CP ratio (24.96%), while Vicia narbonensis L. and Medicago trancatula Gaertn. stand out in terms of ADF. In terms of NDF ratio, Trifolium resupinatum L. (36.29%), Coronilla varia L. (36.49%) and Trifolium repens L. (36.72%) stand out, respectively. In terms of RFV, Trifolium resupinatum L. (179.20) had the highest value and the lowest in Trifolium arvense L. (109.96). In terms of total gas was highest value was detected in Medicago trancatula Gaertn. (50.89 ml) and Trifolium repens L. (50.52 ml) the lowest TG was detected in Coronilla varia L. (38.81 ml), Trifolium arvense L. (40.27 ml) and Lotus corniculatus L. (40.64 ml). The highest and the lowest ME were determined by Vicia narbonensis L. (10.45 MJ kg-1 DM) and Trifolium arvense L. (8.52 MJ kg-1 DM), the highest OMD degrees were determined by Vicia narbonensis L. (68.54%), Medicago trancatula Gaertn. (68.02%) and Trifolium repens L. (67.96%) lowest OMD degrees Trifolium arvense L. (56.10%) and Coronilla varia L. (56.62%) respectively. In conclusion, it has been determined that the TG production, ME, OMD and RFV content of Trifolium repens L., Trifolium resupinatum L. and Medicago trancatula Gaertn. were significantly higher. [ABSTRACT FROM AUTHOR]

Background: Combinations of grasses and nitrogen-fixing legumes are ubiquitous in most natural and derived pastoral grasslands. This was not formerly the case in New Zealand's unique indigenous grasslands that are now frequently impacted by exotic pasture grasses and legumes. Understanding the co-existence of native and exotic plants is the broad focus of this research. Aims: Spillover of nitrogen (N) from clovers to grasses in diverse pasture is well known. We question whether grasses provide reciprocal nutritional benefits to legumes. Does the mutual exploitation of soil biogeochemistry by legumes and grasses help to explain their coexistence and, if so, does this have implications for biodiversity in NZ's novel native grassland communities? Methods: Combinations of grasses and legumes, including a native tussock grass, were grown in a nutrient-poor (low P, S, Ca, Mg, Mn, and B) high country soil in a pot experiment, quantifying the foliar acquisition of nutrients from soil. Field data were obtained by sampling foliage of clover in single- and mixed-species patches in a more fertile lowland pasture. Results: Benefits of legume and grass growing together were reflected in enhanced productivity and higher uptake of a range of key nutrients. This was most evident but not restricted to a combination of two exotic species: cocksfoot and white clover. In the nutrient-poor soil, legumes grew better in combination with different species of introduced grasses. Uptake of key elements from soil to plants significantly differed with combinations of legumes and grasses compared to individual species. Elevated concentrations of P, K and S were recorded in clover when growing with grasses, although Ca uptake was lower. Expected reciprocal reduction of clover N or enhanced grass N were not recorded. Mass balance data (total extraction of key nutrients from the soil pool) showed that combination of grasses and legumes exploit soil nutrients (particularly P, Zn, Mn and Mo) more effectively than single species alone. In grasses, only tissue concentrations of K, S and Zn significantly increased when growing with legumes, but native tussock grass procured less nutrients when growing with the exotic legumes. Field sampling of clover from the more fertile lowland soil showed significantly higher foliar concentrations of K, Mn, Cu and B, but less Ca. Conclusions: The findings are indicative of a mutualistic relationship: legumes derive nutritional benefits from growing with grasses. Native tussock grass contained less N when growing with the exotic legumes, suggesting less compatibility and a lack of adaptation to coexistence. [ABSTRACT FROM AUTHOR]

Frost seeding is a low‐cost effective strategy to introduce legumes into existing perennial pastures; however, it has been deemed unreliable in the upper southeast USA. We evaluated frost seeding planting rate effects of clover (Trifolium spp.) during the year of establishment on productivity and nutritive value of clover‐tall fescue [Festuca arundinacea (Schreb.) Darbysh.] pastures. Ball (T. nigrescens Viv.), crimson (T. incarnatum L.), red (T. pratense L.), and white (T. repens L.) clover were frost seeded in the Piedmont and Coastal Plain for 3 yr (2017–2019). Planting rates were 0X, 0.5X, 1X, 1.5X, and 2X of the recommended rate (X) of 5.6, 13.5, 11.2, and 5.6 kg ha–1 for ball, crimson, red, and white clover, respectively. At Coastal Plain, clover accounted for ≤16%. At Piedmont, ball, crimson, red, and white clover accounted for up to 27, 48, 21, and 15%, respectively. Notwithstanding similar clover frequency early in the growing season at both locations, competition from tall fescue in a higher rainfall environment is attributed to the lower clover contribution at Coastal Plain. Increasing clover frost‐seeding rate resulted in greater crude protein (130–154 g kg–1) and total digestible nutrients (586–610 g kg–1) only at Piedmont. The results from this study support the practice of frost‐seeding ball, crimson, red, and white clover at planting rates of 5.6, 20.2, 11.2, and 5.6 kg ha–1, respectively, into tall fescue pastures in the Piedmont; however, minimal or no benefits of frost seeding clover were observed in the Coastal Plain. Core Ideas: Frost‐seeded clover increased diversity and nutritive value of tall fescue pastures at Piedmont.At Piedmont, ball, crimson, red, and white clover accounted for 13–48% of the forage.Minimal, or no benefits, of frost seeding clover were measured at Coastal Plain.At Coastal Plain, clover accounted for ≤16% of the total herbage harvested. [ABSTRACT FROM AUTHOR]

Plants synthesize a plethora of chemical defence compounds, which vary between evolutionary lineages. We hypothesize that plants evolved the ability to utilize defence compounds synthesized and released by neighbouring heterospecific plants. In two experiments, we incubated clover (Trifolium repens L.) seedlings with individual benzoxazinoid (BX) compounds (2,4-dihydroxy-1,4-benzoxazin-3-one, 2-hydroxy-1,4-benzoxazin-3-one, benzoxazolinone, and 6-methoxy- benzoxazolin-2-one), a group of bioactive compounds produced by cereals, to allow clover BX uptake. Subsequently, we transplanted the seedlings into soil and quantified BX root and shoot content and invasion of root-knot nematodes in clover roots up to 8 weeks after transplantation. We show that clover root uptake of BXs substantially enhanced clover's resistance against the root-knot nematode Meloidogyne incognita. This effect lasted up to 6 weeks after the clover roots were exposed to the BXs. BXs were absorbed by clover roots, and then translocated to the shoots. As a result of clover metabolization, we detected the parent BXs and a range of their transformation products in the roots and shoots. Based on these novel findings, we envisage that co-cultivation of crop species with complementary and transferable chemical defence systems can add to plant protection. [Display omitted] • Clover roots take up and metabolize cereal benzoxazinoids (BXs). • BXs are translocated into aboveground clover tissues. • BX transformation products are a result of enzymatic reactions in clover. • BXs uptake enhanced clover's resistance against root-knot nematodes. [ABSTRACT FROM AUTHOR]

White clover (Trifolium repens) is an allotetraploid pasture legume widely used in moist temperate climates, but its vulnerability to drought, grazing pressure and pests has restricted its wider use. A related species, Caucasian clover (Trifolium ambiguum), is a potential source of resistances to drought, cold, grazing pressure and pests that could potentially be transferred to white clover by interspecific hybridization. Although direct hybridization has been achieved with difficulty, the hybrids have not been easy to backcross for introgression breeding and no interspecific chromosome recombination has been demonstrated. The present work shows that interspecific recombination can be achieved by using Trifolium occidentale , one of the ancestral parents of T. repens , as a bridging species and that large white clover breeding populations carrying recombinant chromosomes can be generated. A 4 x hybrid between T. ambiguum and T. occidentale was crossed with T. repens and then backcrossed for two generations. Five backcross hybrid plants with phenotypes appearing to combine traits from the parent species were selected for FISH-GISH analyses. Recombinant chromosome segments from T. ambiguum were found in all five plants, suggesting that recombination frequencies were significant and sufficient for introgression breeding. Despite early chromosome imbalances, the backcross populations were fertile and produced large numbers of seeds. These hybrids represent a major new resource for the breeding of novel resilient forms of white clover. [ABSTRACT FROM AUTHOR]

Legume-based forage plant mixtures are known to increase biomass production over the mixture species grown as pure stands (overyielding), which has partly been attributed to enhanced nitrogen availability by legumes. However, the relative importance of underlying processes of these positive diversity effects and their drivers are not fully understood. Here we assessed if outcome and causes of diversity effects depend on the legume-species genetic identity. Over five years, we cultivated different white clover (Trifolium repens) populations, a grass and forb species in pure stands and clover-based mixtures and recorded biomass yield. Complementarity and selection effects of mixtures and relative yields of mixture species were calculated based on both unfertilized and nitrogen-fertilized non-leguminous pure stands. Results showed that the clover population altered the overall strength of diversity effects as well as the direction and magnitude of their temporal trends, at least for the grass component of mixtures. Differences in diversity effects between clover populations diminished when fertilized instead of unfertilized non-leguminous pure stands were considered. Hence, a part of these differences likely results from dissimilar effects of clover populations on nitrogen availability. The findings reveal the possibility to improve overyielding of legume-based forage plant mixtures by decisions on legume-species genetic identity. [ABSTRACT FROM AUTHOR]

Key message: Accurate genomic prediction of yield within and across generations was achieved by estimating the genetic merit of individual white clover genotypes based on extensive genetic replication using cloned material. White clover is an agriculturally important forage legume grown throughout temperate regions as a mixed clover–grass crop. It is typically cultivated with low nitrogen input, making yield dependent on nitrogen fixation by rhizobia in root nodules. Here, we investigate the effects of clover and rhizobium genetic variation by monitoring plant growth and quantifying dry matter yield of 704 combinations of 145 clover genotypes and 170 rhizobium inocula. We find no significant effect of rhizobium variation. In contrast, we can predict yield based on a few white clover markers strongly associated with plant size prior to nitrogen fixation, and the prediction accuracy for polycross offspring yield is remarkably high. Several of the markers are located near a homolog of Arabidopsis thaliana GIGANTUS 1, which regulates growth rate and biomass accumulation. Our work provides fundamental insight into the genetics of white clover yield and identifies specific candidate genes as breeding targets. [ABSTRACT FROM AUTHOR]

Salinity is an factor which has a critical influence on seed germination and plant establishment. During the present study the effect of salinity on seeds germination, seedling growth and chlorophyll content of Trifolium repens was studied. Experiments were conducted in laboratory condition. The salinity was induced using three concentration of NaCl (0 mM NaCl, 40 mM and 80 mM). Determinations were recorded in three periods, after (3, 10 and 17 days) and were analysed percentage of germination, MDG and DGS, seedling growth and chlorophyll content. In normal condition Trifolium repens showed highest percentage of germination 79.33%, while in stress salt condition percentage of germination was reduced in proportion to the increase in saline concentration. In salt stress condition we observed that the mean daily germination (MDG) decreased, while daily germination speed (DGS) increased. The effect of the NaCl concentration on the growth in the clover seedlings they showed values between 2.372 cm on the V3 variant and 3.603 cm on the Vo variant. The application of treatments that induced saline stress led to a significant decrease in growth in proportion to the level of differences between treatments. Referring to the effect of the environment on the accumulation of chlorophyll, it was observed that the chlorophyll content decreased under conditions of saline stress (24.15 SPAD). Salt tolerance data may be used to select clover with the highest potential for agronomic production. [ABSTRACT FROM AUTHOR]

The natural abundance technique is used to estimate the amount of N fixed by a legume, but the B value of this particular species has to be known first. This value, however, varies with the rhizobium strains and climatic conditions. To assess this variation range for forage legumes growing under Uruguayan conditions, seeds of Lotus corniculatus L., Trifolium repens L. and Trifolium pratense L. were sown in pots containing vermiculite-sand and inoculated with a commercial or a promissory rhizobium strain, and grown in a greenhouse during the winter and spring, or in a growth chamber that simulated summer temperatures. At harvest, B values were determined by analyzing δ15N in shoots, and their proportion of N derived from air (%Ndfa) were also estimated. All B values were within the reported ranges. The rhizobium strain affected B only in L. corniculatus, resulting in a 0.55‰ shift between the commercial and the research strains. The growing seasonal effect, however, was important across the three species, with B values becoming more negatives as the temperature and the isotopic fractionation increased. However, the impact of these B value changes on the associated %Ndfa values were not always agronomically relevant, but depended on the particular legume–rhizobia combination. [ABSTRACT FROM AUTHOR]

Summary: Allopolyploid speciation and chemical defense diversification are two of the most characteristic features of plant evolution; although the former has likely shaped the latter, this has rarely been documented. Here we document allopolyploidy‐mediated chemical defense evolution in the origin of cyanogenesis (HCN release upon tissue damage) in white clover (Trifolium repens).We combined linkage mapping of the loci that control cyanogenesis (Ac, controlling production of cyanogenic glucosides; and Li, controlling production of their hydrolyzing enzyme linamarase) with genome sequence comparisons between white clover, a recently evolved allotetraploid, and its diploid progenitors (Trifolium pallescens, Trifolium occidentale).The Ac locus (a three‐gene cluster comprising the cyanogenic glucoside pathway) is derived from T. occidentale; it maps to linkage group 2O (occidentale subgenome) and is orthologous to a highly similar cluster in the T. occidentale reference genome. By contrast, Li maps to linkage group 4P (pallescens subgenome), indicating an origin in the other progenitor species.These results indicate that cyanogenesis evolved in white clover as a product of the interspecific hybridization that created the species. This allopolyploidization‐derived chemical defense, together with subsequent selection on intraspecific cyanogenesis variation, appears to have contributed to white clover's ecological success as a globally distributed weed species. [ABSTRACT FROM AUTHOR]

Nitrogen fertilizer use is generally restricted in bermudagrass [Cynodon dactylon (L.) Pers.]-white clover (Trifolium repens L.) forage systems because it stimulates grass growth and increases competition with the clover, compromising forage nutritive value and prospective forage accumulation. Enhanced efficiency fertilizer nitrogen (N) products hold potential to improve white clover persistence in bermudagrass- clover pastures while providing supplemental N required by the grass. This study evaluated the effect of different enhanced efficiency N formulations (Environmentally Smart Nitrogen [ESN]; methylene urea; SuperU; and 75% ESN, 25% urea blend) and untreated urea on forage accumulation, nutritive value, and legume persistence in a 'Wrangler' bermudagrass and 'Durana' white clover mixture. Nitrogen was applied at four rates (0, 112, 224, and 448 kg N ha-1) in two equal applications each year. By the second year, white clover stands were lesser at the greatest N rates. All enhanced efficiency N sources maintained white clover similar to the unfertilized grass-clover control, but only ESN improved white clover persistence over urea. Total season forage accumulation increased linearly with increasing N rates within all three growing seasons, but dry weather conditions in the last 2 yr resulted in less forage accumulation. Nutritive value decreased with maturity throughout the growing season, but ESN maintained clover in the pasture resulted in overall less fiber components and greater digestibility. Although there was no effect of N source on forage accumulation, the ability of ESN to maintain clover could make it a viable option for fertilization in bermudagrass-white clover mixtures. [ABSTRACT FROM AUTHOR]

Keywords: Clover; grass; legumes; forage; alfalfa; herbicide resistance; buttercup; chicory; proximal hyperspectral sensing EN Clover grass legumes forage alfalfa herbicide resistance buttercup chicory proximal hyperspectral sensing 249 251 3 05/17/22 20220801 NES 220801 In this special issue of NZJA, we have collected papers that focus on new science in the discipline of plant sciences. Ranunculus acris control in dairy pasture - a comparison of herbicides, plant growth promoters, a bioherbicide and pregraze mowing. Clover, grass, legumes, forage, alfalfa, herbicide resistance, buttercup, chicory, proximal hyperspectral sensing Continuing the legume theme, Gerard et al. ([7]) present an interesting data set comparing yields of eight perennial clover cultivars under field conditions over two years. [Extracted from the article]

Perennial ryegrass (Lolium perenne L.) is cultivated in many countries for its high yield and good quality forage. Its cultivars have specific functional traits, such as phenology, growth habit and rate, which affect the competitiveness and productivity of mixtures. The cultivation of new cultivars of perennial ryegrass or mixtures of cultivars in swards is one of the complementary measures to improve the condition of swards. The study was aimed to determine the productivity potential of three newer, less investigated Lithuanian perennial ryegrass (Lolium perenne L.) cultivars 'Elena DS', 'Raminta', 'Verseka', and cultivar mixtures in single-species swards and in mixtures with legumes - white and red clover. The experiment was set up in the central part of Lithuania in the Nemoral climate zone. Mineral fertilisers were not used for the mixtures with legumes, singlespecies crops were fertilised with N150 kg ha-1 yr-1. Over the two experimental years, the average dry matter yield of perennial ryegrass was 8.00 t ha-1 for the 'Elena DS', 7.4 t ha-1 for 'Verseka', 6.9 t ha-1 for 'Raminta' and 7.4 t ha-1 for the cultivar mixture. In the 1st year of sward use, the productivity of the perennial ryegrass cultivars did not differ significantly. In the 2nd year, the productivity of 'Elena DS' was significantly higher compared with that of the other cultivars cultivated in single-species crops. The influence of functional traits of the cultivars was significant in the first year of cultivation and persisted in single-species swards but not in mixtures from the second year onwards. The plants of the cultivar 'Elena DS' allowed the development of clover in the mixture, resulting in an increase in herbage productivity and crude protein content. The results of the experiment suggest that a mixture of perennial ryegrass cultivars can be used in swards, as a similar dry matter yield was recorded compared to a single-cultivar swards. However, the benefits of swards may vary from season to season, and more research is needed to assess the impact of a mixture of cultivars on grass productivity and quality with ageing of swards and accumulation in different environmental conditions. [ABSTRACT FROM AUTHOR]

Background and Aims The drivers of white clover (Trifolium repens) architecture and productivity are still imperfectly understood. Our aim here was to investigate the impact of genetic background, neighbourhood and season on different architectural traits, clover and total biomass yield, as well as the relationship between those traits and yield. Methods We grew eight white clover populations in pure stands and in mixed stands with contrasting mixture partners. Over four consecutive regrowth periods within 1 year, we measured trait sizes and determined clover and total yield amounts. Key Results The size of the architectural traits differed between populations and changed in response to neighbourhood and season. Population did not affect the sign or degree of those changes. Among the tested factors, season was by far the most important driver of white clover architecture, with the seasonal pattern notably differing between architectural traits. Clover and total yield were positively related to the architectural traits leaf area, petiole length, internode length and specific leaf area. Whereas the direction of the relationship was widely unaffected, its magnitude was clearly altered by neighbourhood and season. Conclusions Our results show that seasonal effects are the key for a deeper understanding of the architecture of white clover individuals and to improve the productivity of white clover communities. [ABSTRACT FROM AUTHOR]

Grapevine leafroll-associated virus 3 (GLRaV-3), an economically significant pathogen of grapevines, is transmitted by Pseudococcus calceolariae , a mealybug commonly found in New Zealand vineyards. To help inform alternative GLRaV-3 control strategies, this study evaluated the three-way interaction between the mealybug, its plant host and the virus. The retention and transmission of GLRaV-3 by P. calceolariae after access to non- Vitis host plants (and a non-GLRaV-3 host) White clover (Trifolium repens L. cv. "Grasslands Huia white clover"), Crimson clover (T. incarnatum), and Nicotiana benthamiana (an alternative GLRaV-3 host) was investigated. For all experiments, P. calceolariae first instars with a 4 or 6 days acquisition access period on GLRaV-3-positive grapevine leaves were used. GLRaV-3 was detected in mealybugs up to 16 days on non- Vitis plant hosts but not after 20 days. GLRaV-3 was retained by second instars (n = 8/45) and exuviae (molted skin, n = 6/6) following a 4 days acquisition period on infected grapevines leaves and an 11 days feeding on non- Vitis plant hosts. Furthermore, GLRaV-3 was transmitted to grapevine (40−60%) by P. calceolariae second instars after access to white clover for up to 11 days; 90% transmission to grapevine was achieved when no alternative host feeding was provided. The 16 days retention period is the longest observed in mealybug vectoring of GLRaV-3. The results suggest that an alternative strategy of using ground-cover plants as a disrupter of virus transmission may be effective if mealybugs settle and continue to feed on them for 20 or more days. [ABSTRACT FROM AUTHOR]

Pasture species complementarity leading to increased dry matter (DM) production has been observed in multispecies (MS) swards which include legumes and forage herbs along with grasses. This effect has been measured in mechanically defoliated plots with little data available from grazing scenarios. There is a scarcity of data available regarding individual forage herb species contribution to increased sward DM production where only plant functional group has been monitored previously. The objective of this three year study was to assess the DM production, N fertiliser response and change of botanical composition in grazed plots across nine MS sward mixtures compared to a PRG monoculture. Multispecies swards included various combinations of species from the three plant functional groups; N fertiliser treatments of 0, 100, 150 and 200 kg N/ha/year were applied. While year influenced the effect of sward mixture on annual DM production, swards that included white clover (Trifolium repens. L.) produced an average of 1688 kg DM/ha/year more than those which did not (P < 0.05); including forage herbs did not increase either annual or seasonal sward DM production. In the final year of the study sward chicory (Chicorium intybus. L.) content was 5% in mixtures including three plant functional groups while ribwort plantain (Plantago lanceolate. L.; PL) content was 37% in the same sward types. Although PL did not increase grazed sward DM production in the current study it did persist well under grazing and may provide other beneficial ecosystem services in dairy grazing systems. • Ten different sward mixtures were assessed under four different rates of chemical nitrogen within a grazing protocol. • Inclusion of white clover in sward mixtures increased dry matter production. • Inclusion of forage herbs in sward mixtures was not associated with dry matter production. • Ribwort plantain was persistent under intensive grazing at all nitrogen application rates. [ABSTRACT FROM AUTHOR]

Molecular characterization of genetically modified plants can provide crucial information for the development of detection and identification methods, to comply with traceability, and labeling requirements prior to commercialization. Detailed description of the genetic modification was previously a challenging step in the safety assessment, since it required the use of laborious and time-consuming techniques. In this study an accurate, simple, and fast method was developed for molecular characterization of genetically modified (GM) plants, following a user-friendly workflow for researchers with limited bioinformatic capabilities. Three GM events from a diverse array of crop species—perennial ryegrass, white clover, and canola—were used to test the approach that exploits long-read sequencing by the MinION device, from Oxford Nanopore Technologies. The method delivered a higher degree of resolution of the transgenic events within the host genome than has previously been possible with the standard Illumina short-range sequencing strategies. The flanking sequences, copy number, and presence of backbone sequences, and overall transgene insertion structure were determined for each of the plant genomes, with the additional identification of moderate-sized secondary insertions that would have previously been missed. The proposed workflow takes only about 1 week from DNA extraction to analyzed result, and the method will complement the existing approaches for molecular characterization of GM plants, since it makes the process faster, simpler, and more cost-effective. [ABSTRACT FROM AUTHOR]

Background: Direct plant uptake of organic nitrogen (N) may be important for plant N nutrition, but we lack knowledge of how the concentration and form of external N influence organic N uptake and plant N status. Aims: We investigated the uptake of the amino acid asparagine (Asn) in white clover in the presence of different inorganic, organic and total N concentrations. Methods: Actively N2‐fixing white clover seedlings were for one week exposed to combinations of NO3- (3–30 µmol N kg−1 sand DW) and Asn (3–30 µmol N kg−1 sand DW), whereafter the Asn uptake rate was determined by addition of 13C4‐Asn. Shoot and root amino acid profiles were also analyzed. Results: Increasing NO3- and total N concentrations decreased 13C4‐Asn uptake rates and internal clover Asn content. In addition, total N and NO3- also affected amino acid profiles, with Asn, Asp, Glu, Gln, Cys, Gly, Pro, Ser, and Ala being more related to the low N doses, and Thr, Val, Ile, Leu, Phe, Tyr, Trp, and Met being more abundant at increasing N doses. Conclusions: Asn uptake rate in white clover is reduced by increasing inorganic N. Plant amino acid profiles are likely to be a more sensitive indicator of N supply. [ABSTRACT FROM AUTHOR]

Glandular trichomes deter herbivores and benefit the plants that possess them. I Parentucellia viscosa i captured small-sized arthropods including spider mites, major herbivores of I T. repens i . GLO:69VH/01jan21:bes21836-fig-0001.jpg PHOTO (COLOR): . gl Photo 1: Parentucellia viscosa (Orobanchaceae), a plant species bearing glandular trichomes that secret viscous mucus onto the surfaces of its flowers, leaves, and stems. [Extracted from the article]

New Zealand pastoral productivity relies heavily on biological nitrogen (N) fixation from rhizobia bacteria. Cadmium (Cd), present in pasture soils as an impurity in phosphate fertilisers, may have toxic effects on both plant growth and rhizobia activity. Effects of Cd on growth of seedlings of a white clover cultivar 'Grasslands Tribute', in the absence and presence of the N2-fixing Rhizobium leguminosarum bv. trifolii strain TA1, were assessed in vermiculite microcosm assays. The lowest observable effect concentrations resulting in significantly lower white clover shoot weights than those grown without Cd were 0.07 mg Cd kg−1 (measured as Ca(NO3)2-extractable Cd, Cdextractable) in the absence of Rhizobium, and 2.33 mg Cdextractable kg−1 for Rhizobium-inoculated seedlings. Shoot N content was unaffected in white clover exposed to <5 mg Cdextractable kg−1. The results indicate symbiosis with Rhizobium strain TA1 conferred tolerance to white clover 'Grasslands Tribute' against Cd toxicity, and that this symbiosis is unlikely to be adversely affected by Cd concentrations reported (<0.003 mg Cdextractable kg−1) in New Zealand pasture soils. [ABSTRACT FROM AUTHOR]

We tested whether selection of ryegrass for reduced root hair length and density would reduce root competition on white clover for phosphate (P). A Rhizosheath Selection Tool was used to select two ryegrass populations with contrasting root hair traits. These were grown at five soil P levels in a glasshouse experiment and rhizosheath trait selection had no effect on growth or shoot P concentrations. The ryegrass populations were also grown with white clover in soils with Olsen P12 or 19 mg L−1. In the Olsen P12 soil, clover grown with the smaller rhizosheath ryegrass had significantly heavier shoots and contained more P than clover grown with the larger rhizosheath ryegrass. In the Olsen P19 soil differences in ryegrass rhizosheath had no effect on clover growth. The results showed that under the experimental conditions, grass-clover competition for soil P could be modified by the rhizosheath traits of ryegrass. [ABSTRACT FROM AUTHOR]

The purpose of the study was to determine the impact of growth regulators RENI-RENI D and biofertilizers Bormax-Molibdenit on crude protein yield, energy yield and feed units in dry feed of bird's-foot-trefoil and white clover. For white clover, the regulator RENI had the best result, as it increased the crude protein yield by 39.23% (P <0.05), FUM by 20.83% and FUG by 20.71% compared to the nontreated variant. For bird'sfoot- trefoil, the highest crude protein yield (1731.77 kg/ha) was found in the treatment with Bormax+Molybdenit. The combination of biofertilizers was most effective also for the yield of fodder units in the harvested mass. The increase of FUM and FUG was by 23.82%. There was a greater effect of the stimulatory action of Bormax + Molybdenit preparations on the feed unit of bird's-foot-trefoil than in white clover. A very good correlation dependence was found between crude protein yield in biomass from the variants with regulators and biofertilizers, with empirically calculated values of gross energy (r = 0.908 - for bird's-foot-trefoil and r = 0.911 - for white clover), metabolisable energy (r = 0.912 - for bird's-foot-trefoil and r = 0.887 - for white clover) and the feed unit value of bird's-foot-trefoil (r = 0.910 - FUM and r = 0.911 - FUG) and white clover (r = 0.884 - FUM and r = 0.854 - FUG. The developed graphical regression models can be successfully used for the approximate determination of energy and fodder yields through the crude protein yield. The coefficients of determination for energy yield (R2 = 0.976-0.983) and for yield of fodder units (R2 = 0.983-0.984) are sufficiently high with high statistical significance (P <0.001). [ABSTRACT FROM AUTHOR]

The living mulch permanence along with the succession of their weed infestation in an apple orchard were evaluated at the Research Station, Wrocław University of Environmental and Life Sciences. The perennial cover crops: white clover and colonial bent grass, as well as the annual dwarf nasturtium, were sown as living mulches in apple tree rows, in the year of establishing the orchard. Blue fescue was sown one year later to replace the dwarf nasturtium. The percent of covers and temporal dominance dynamics of weeds were estimated during the first 13 years of the orchard maintenance. The occurrence of annual weeds, which had been abundant in all the living mulches in the year of their sowing, decreased in the following years of orchard maintenance. Conversely, the dominance of several perennial weed species increased as the orchard reached the full cropping period. White clover exhibited the lowest permanence. Dynamic spreading of Elymus repens (L.) Gould and other species from the Poaceae family was the direct cause of this cover crop disappearance. The presence of perennial dicotyledonous weeds, primarily Taraxacum officinale Web. and Convolvulus arvensis L., also contributed to the diminished sod of all the living mulches. Blue fescue maintained satisfactory dominance relative to colonial bent grass for nearly the entire first decade of the research. Nevertheless, both grass living mulches were present on less than half of the tree row soil surface area, in the thirteenth year after planting of the apple trees. [ABSTRACT FROM AUTHOR]

The EST-SSRs (genic SSRs) are the microsatellites in expressed sequence tags (ESTs). Advancement in functional genomics has contributed mainly for the identification of ESTs in different species and made them available in databases. They are of transcribe regions, so are more conserved and considered with more cross transferability across the taxonomic borders. In Trifolium alexandrinum (Berseem), no expressed sequence tags (ESTs) are available in NCBI database yet. Therefore, in this study by considering the cross transferability potential of EST-SSRs, expressed sequence tags of Trifolium pratense and Trifolium repens were retrieved from NCBI database and their EST-SSRs were in silico identified. We retrieved 1014 ESTs for SSR identification from both Trifolium species and identified 198 EST-SSRs from them. In identified EST-SSRs, trinucleotide SSRs repeats were found to be more frequent. Of these 198 in silico identified EST-SSRs, 44 showed cross species amplification in T. alexandrinum and was proved for their transferability potential. The identified EST-SSRs could be a great source for genetic diversity and population genetics studies of Trifolium species. These EST-SSRs could be further screened to investigate their linkage to disease resistance in Trifolium species. [ABSTRACT FROM AUTHOR]