Forage Grasses Research Articles

LcASR enhances tolerance to abiotic stress in Leymus chinensis and Arabidopsis thaliana by improving photosynthetic performance

SUMMARYAs a crucial forage grass, Leymus chinensis plays significant roles in soil and water conservation owing to its robust stress resistance. However, the underlying molecular mechanisms of its stress tolerance remain unclear. In this study, a novel gene, designated as LcASR (Abiotic Stress Resistance in Leymus chinensis), imparting resilience to both high light and drought, was identified. Under normal growth conditions, heterologous overexpression of LcASR in Arabidopsis (HO lines) showed no significant difference in appearance compared to wild‐type. Nevertheless, HO lines accumulate significantly higher chlorophyll content during the dark‐to‐light transition compared to the wild‐type, indicating that the LcASR protein participates in chlorophyll synthesis during chloroplast development. Meanwhile, transgenic Arabidopsis and L. chinensis plants exhibited resistance to abiotic stresses such as high light and drought. Photosystem complexes analysis revealed that LHCII proteins remained stable within their respective complexes during high light stress. We hypothesize that LcASR may play a role in fine tuning of chlorophyll synthesis to enable plant adaptation to diverse stress conditions. Moreover, overexpression of LcASR in L. chinensis led to agronomically valuable traits such as deeper green color, higher biomass accumulation, prolonged withering period, and extended grazing durations. This study uncovers a novel gene in L. chinensis that enhances forage yield and provides valuable genetic resources for sheepgrass breeding.

A scoping review of communal rangelands management in southern Africa: towards sustainable management of rangelands

This paper investigates the impacts of policy and governance institutions on rangeland management practices in southern Africa. A scoping review was conducted, using literature from Web of Science, JSTOR, Scopus and Africa-wide bibliographic databases in the past three decades. The results revealed that several initiatives have been implemented in southern Africa to improve the condition of rangelands, including livestock destocking policies, grazing schemes, improved forage grasses, veld legume reinforcement, high-market beef value chains and agroforestry technology. However, the success of these initiatives has been limited due to a lack of meaningful participation in rangeland management. Moreover, the absence of responsive policies to support communal rangeland management in southern Africa has led to their transformation into unsustainable systems. Additionally, commercial interests often drive national-level policies and tend to disempower traditional institutions, causing conflicts and discord in rangeland management. Therefore, unrolling participatory bottom-up approaches will be essential for inclusive and sustainable rangeland management.

Canopy structure and herbage intake rate of three tropical forage grasses cultivated as pure or mixed stands

Context Using forage grass species with complementary growth and resource-use strategies to enhance forage plant diversity in pastures may be an alternative to traditional monocultures in tropical regions. Aims This study aimed to determine whether a mixture of three perennial tropical forage grasses (Andropogon gayanus cv. Planaltina, Panicum maximum cv. Massai, and Brachiaria brizantha cv. BRS Piatã) could be an alternative to enhance herbage intake rates relative to their respective monocultures. Methods The treatments corresponded to three perennial tropical forage grasses cultivated as monocultures and as a mixture composed of all three species. Defoliation management corresponded to a pre-cutting height of 35 cm and post-cutting height of 17.5 cm. Key results The botanical composition of the mixture was dynamic throughout the experimental period, with variations in the proportion of species across seasons. The upper half of the canopy predominantly comprised leaves for all treatments. The canopy structure of the mixture allowed for greater herbage intake rates than monocultures during winter/early spring. Andropogon gambagrass showed lower herbage intake rates than the other treatments. Conclusions The findings of this study indicate that it is possible to combine tropical forage grass species without compromising canopy structure and grazing animal responses, compared with single-species grass pastures. Implications The selection of forage species for mixed pastures should consider their phenological cycle, growth, and resource-use strategies to achieve temporal complementarity and provide an optimal grazing environment for animals throughout the year.

Seed Germination Responses to Temperature and Osmotic Stress Conditions in Brachiaria Forage Grasses

Seed Germination Responses to Temperature and Osmotic Stress Conditions in Brachiaria Forage Grasses

Genome Editing for Grass Improvement and Future Agriculture

Abstract Grasses, including turf and forage, cover most of the earth’s surface; predominantly important for land, water, livestock feed, soil and water conservation, as well as carbon sequestration. Improved production and quality of grasses by modern molecular breeding is gaining more research attention. Recent advances in genome-editing technologies are helping to revolutionize plant breeding and also offering smart and efficient acceleration on grass improvement. Here, we reviewed all recent researches using (CRISPR)/CRISPR-associated protein (Cas)-mediated genome editing tools to enhance the growth and quality of forage and turf grasses. Furthermore, we highlighted emerging approaches aimed at advancing grass breeding program. We assessed the CRISPR-Cas effectiveness, discussed the challenges associated with its application, and explored future perspectives primarily focusing on turf and forage grasses. Despite the promising potential of genome editing in grasses, its current efficiency remains limited due to several bottlenecks, such as the absence of comprehensive reference genomes, the lack of efficient gene delivery tools, unavailability of suitable vector and delivery for grass species, high polyploidization, multiple homoeoalleles, etc. Despite these challenges, the CRISPR-Cas system holds great potential to fully harness its benefits in grass breeding and genetics, aiming to improve and sustain the quantity and quality of turf and forage grasses.

The Quality characteristics of haylage from forage grasses of tropical pastures: losses, gas production, nutritional value, microbial population and organic acids

Tropical pastures have been little explored for haylage, due to the lack of information on nutritional quality. This study aimed to evaluate the fermentation quality of different genotypes of forage grasses from tropical pastures in the form of haylage. Six genotypes of grasses were used to evaluate the fermentation characteristics, losses and presence of microorganisms in the in the haylage. The completely randomized design was used for all variables. Data were subjected to analysis of variance with all genotype’s means compared by the Scott Knott’s test at 5% probability. There was effect of interaction between form of material x genotype (P<0.01) on all variables of chemical composition evaluated in the in natura and haylage at the moment of haylage making, except for NDF and N-NH3 (P>0.05). The concentrations of O2 in the haylage after 60 days of storage were lower for the genotypes Xaraés and Tupã. The highest levels of acetic acid were observed in genotypes Xaraés, Planaltina and Tupã. The Planaltina genotype presented the highest DM loss in the process of production and storage of the haylage, averaging 8.2 ± 0.37%. The haylage of the species B. brizantha and M. maximus presented better nutritional characteristics.

Evaluation of Germination and Early Seedling Growth of Different Grasses Irrigated with Treated Mine Water

Coal mining is known to have negative impacts on the environment, necessitating land rehabilitation after mining activities. Amongst the problems associated with coal mining is the accumulation of acid mine drainage characterized by large amounts of heavy metals and high acidity. The impact of these environmental problems on the ecosystem around mining areas underscores a need to devise strategies that will ensure sustainable restoration of the ecosystem integrity to ensure environmental protection. Of these, treatment of acid mine drainage using calcium sulfate dihydrate, which is subsequently used for irrigation during phytoremediation, holds great promise for restoration of open-cast mines. However, although grasses are used for rehabilitation of coal mined areas, the impacts of treated mine water on the germination, seedling emergence, and plant growth of grasses are not well known. The aim of the study was to evaluate the germination and early seedling growth responses of different forage grasses to treated mine water. Seven forage grass species were selected, with four species represented by two varieties while others were represented by one variety, totaling 11 forage grasses. For each plant entry, 100 seeds were placed in J.R. Petri’s dishes lined with Whatman No. 2 filter paper and watered with distilled and mine water to assess germination. For the seedling establishment experiment, only five species were studied, in which twenty seeds per species were sown in pots containing mine soil and irrigated using distilled and treated mine water. The final germination percentage (FGP), germination rate index (GRI), corrected germination rate index (CGRI), and T50 were determined for the germination trail and total biomass was assessed for the seedling growth trail. The highest FGP for all grasses was attained under controlled conditions, using distilled water, ranging from 38–94%. All grasses germinated when watered using treated mine water and had a FGP ranging from 20–91%. Relative to distilled water, GRI and CGRI were highest only for L. multiflorum cv AgriBoost when seeds were watered using the treated mine water. All grasses watered with treated mine water produced high biomass for the first two weeks, after which biomass production started to decline. Two grasses, Eragrostis curvula cv Ermelo and Lolium multiflorum cv Archie, showed tolerance to treated mine water irrespective of its high electrical conductivity (557 mS∙m−1). Therefore, these grasses could be used in the rehabilitation of coal-mined areas irrigated with treated mine water.

Genome-wide analysis of the WRKY gene family and their response to low-temperature stress in elephant grass.

Elephant grass (Cenchrus purpureus) is a perennial forage grass characterized by tall plants, high biomass and wide adaptability. Low-temperature stress severely limits elephant grass biomass and geographic distribution. WRKY is one of the largest families of plant-specific transcription factors and plays important roles in plant resistance to low-temperature. However, the understanding of the WRKY family in grasses is limited. In this study, we conducted a genome-wide characterization of WRKY proteins in elephant grass, including gene structure, phylogeny, expression, conserved motif organization, and functional annotation, to identify key CpWRKY candidates involved in cold tolerance. In this study, a total of 176 WRKY genes were identified in elephant grass. It was found that 172 were unevenly distributed across its 14 chromosomes, while the remaining 4 genes were not anchored to any chromosome. The genes were classified into three groups based on their WRKY conserved domains and zinc finger motifs. There were 12, 8, 19, 27, 12, 18 and 80 CpWRKYs belonging to group I, group IIa, group IIb, group IIc, group IId, group IIe and group III, respectively. We hypothesized that the ancient subgroup IIc WRKY gene is the ancestor of all WRKY genes in elephant grass. Most CpWRKYs in the same group have similar structure and motif composition. A total of 169 duplicate gene pairs were identified, suggesting that segmental duplication might have contributed to the expansion of the CpWRKY gene family. Ka/Ks analysis revealed that most of the CpWRKYs were subjected to purifying selection during the evolution. It was also found that six genes (CpWRKY51, CpWRKY81, CpWRKY100, CpWRKY101, CpWRKY140 and CpWRKY143) exhibited higher expression in roots compare to leaves, and were significantly induced by low temperature stress. Among them, CpWRKY81 had the highest expression under low-temperature stress, and its over-expression significantly enhanced the cold tolerance in yeast. In this study, we characterized WRKY genes in elephant grass and further investigated their physicochemical properties, evolution, and expression patterns under low-temperature stress. This research provides valuable resources for identifying key CpWRKY genes that contribute to cold tolerance in elephant grass.

Unravelling the molecular mechanism underlying drought stress tolerance in Dinanath (Pennisetum pedicellatum Trin.) grass via integrated transcriptomic and metabolomic analyses

Dinanath grass (Pennisetum pedicellatum Trin.) is an extensively grown forage grass known for its significant drought resilience. In order to comprehensively grasp the adaptive mechanism of Dinanath grass in response to water deficient conditions, transcriptomic and metabolomics were applied in the leaves of Dinanath grass exposed to two distinct drought intensities (48-hour and 96-hour). Transcriptomic analysis of Dinanath grass leaves revealed that a total of 218 and 704 genes were differentially expressed under 48- and 96-hour drought conditions, respectively. The genes that were expressed differently (DEGs) and the metabolites that accumulated in response to 48-hour drought stress mainly showed enrichment in the biosynthesis of secondary metabolites, particularly phenolics and flavonoids. Conversely, under 96-hour drought conditions, the enriched pathways predominantly involved lipid metabolism, specifically sterol lipids. In particular, phenylpropanoid pathway and brassinosteroid signaling played a crucial role in drought response to 48- and 96-hour water deficit conditions, respectively. This variation in drought response indicates that the adaptation mechanism in Dinanath grass is highly dependent on the intensity of drought stress. In addition, different genes associated with phenylpropanoid and fatty acid biosynthesis, as well as signal transduction pathways namely phenylalanine ammonia-lyase, putrescine hydroxycinnamoyl transferase, abscisic acid 8’-hydroxylase 2, syntaxin-61, lipoxygenase 5, calcium-dependent protein kinase and phospholipase D alpha one, positively regulated with drought tolerance. Combined transcriptomic and metabolomic analyses highlights the outstanding involvement of regulatory pathways related to secondary cell wall thickening and lignin biosynthesis in imparting drought tolerance to Dinanath grass leaves. These findings collectively contribute to an enhanced understanding of candidate genes and key metabolites relevant to drought response in Dinanath grass. Furthermore, they establish a groundwork for the creation of a transcriptome database aimed at developing abiotic stress-tolerant grasses and major crop varieties through both transgenic and genome editing approaches.

Agronomic performance and nutritive value of Urochloa species, Desho and Rhodes grass grown in sub-humid central Ethiopia

Improved forage grasses with high quality and biomass are a crucial additional feed source for cereal-livestock farming in Ethiopia. This study compared the performance of 4 Urochloa species [U. brizantha (DZF-13379), U. humidicola (DZF-9222), U. decumbens ‘Basilisk’ (DZF-10871) and U. mutica (DZF-483)] with other 2 commonly used grasses, Rhodes grass (Chloris gayana ‘Massaba’) and Desho grass (Pennisetum glaucifolium local variety Kindu kosha), over 3 years during the main rainy season in Bishoftu in a sub-humid area of Ethiopia. The experiment was conducted using a completely randomized block design. There was significant variation among species for agronomic parameters. The species × year interaction was significant for dry matter yield, plant height, and plot cover but not significant for leaf-to-stem ratio. Nutritional value [ash, acid detergent fiber (ADF), crude protein (CP) and in vitro dry matter digestibility (IVDMD)] was significantly different among species with no differences for neutral detergent fiber (NDF) and acid detergent lignin (ADL). All species showed potential as alternative ruminant feeds with U. mutica and U. brizantha the highest yielding in the sub-humid environment.

GGE biplot analysis for genotype × environment interactions affecting the seed shattering of Psathyrostachys juncea

The Psathyrostachys juncea (Fisch.) Nevski. Is an important forage grass in cold and arid regions. However, its high seed shattering (SS) traits affects seed yield. The SS phenomenon arises from the intricate interplay between its genotype and environment (GE). To gain a comprehensive understanding of SS variations in different Psathyrostachys juncea (Fisch.) Nevski materials under the influence of GE interactions, a two-year experiment was conducted on 300 individual plants at two locations. Utilizing the GGE biplot method, the current research aimed to assess the adaptability and stability of Psathyrostachys juncea (Fisch.) Nevski on SS trait, with a focus on identifying genotype materials conducive to breeding. The analysis of variance indicated that genotype, environment, year, and their interactions exhibited extremely significant effects on SS. Among these factors, the GE interaction showed as the primary contributor to variability in the SS trait of Psathyrostachys juncea (Fisch.) Nevski. The GGE biplot illustrated that Hohhot and Baotou emerged as representative locations with strong discriminative power for the materials. Genotypes 18 and 120 exhibited high SS rates in Hohhot, while 118 and 111 showed high SS rates in Baotou. Genotypes 132 and 177 were identified as ideal genotypes with both high and stable SS rates. These findings serve as valuable references for applications in grazing pastures and provide genotype materials for the genetic improvement and mechanistic analysis of SS traits in Psathyrostachys juncea (Fisch.) Nevski.

Investigation of Cytotoxic Effects of Tragopogon reticulatus Against HepG2 and MCF-7 Cell Lines and Antioxidant, Antimicrobial Effects Against Some Microorganisms

Plants have been used for various purposes throughout history. This subject has received increasing attention in the field of traditional medicine in recent years. Tragopogon reticulatus, as a forage grass plant in turkey, is a species that stands out with rich vitamin and mineral content. The aim of this study was to investigate the antimicrobial, antioxidant, and cytotoxic activities of T. reticulatus. Two separate extracts were prepared at different concentrations using hexane and methanol solvents obtained from the T. reticulatus plant, and cytotoxic activity was evaluated by the MTT Assay (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) method on human liver cancer (HepG2) and human breast cancer (MCF7) cell lines. The antioxidant activity of the extracts obtained from methanol and hexane was determined by the DPPH (2,2-diphenyl 1-picrylhydrazyl) radical scavenging capacity method. Antimicrobial activity was evaluated by the disk diffusion method, and bacteria such as Staphylococcus aureus, Klebsiella pneumoniae, Escherichia coli, Bacillus megaterium, and Candida albicans fungus were used in the study. The hexane extract obtained from the T. reticulatus plant showed a high cytotoxic activity of 44% in the MCF7 cell line, while it showed a 51% dead cell count in the HepG2 cell line. When the antioxidant results were evaluated, it was determined that the DPPH radical scavenging effect of the hexane extract exhibited the most effective activity at 19%. When the antimicrobial results were evaluated, it was determined that the concentrations prepared with hexane exhibited the most effective activity with a zone diameter of 16 mm against B. megaterium. These findings suggest that T. reticulatus plant extracts can be considered as a potential source. These results may shed light on future research into the biological effects of the plant and contribute to the development of new treatment methods.

Comparative physiological and transcriptomic analyses reveal genotype specific response to drought stress in Siberian wildrye (Elymus sibiricus)

Siberian wildrye (Elymus sibiricus) is a xero-mesophytic forage grass with high nutritional quality and stress tolerance. Among its numerous germplasm resources, some possess superior drought resistance. In this study, we firstly investigated the physiological differences between the leaves of drought-tolerant (DT) and drought-sensitive (DS) genotypes under different field water contents (FWC) in soil culture. The results showed that, under drought stress, DT maintained a lower leaf water potential for water absorption, sustained higher photosynthetic efficiency, and reduced oxidative damage in leaves by efficiently maintaining the ascorbic acid-glutathione (ASA-GSH) cycle to scavenge reactive oxygen species (ROS) compared to DS. Secondly, using RNA sequencing (RNA-seq), we analyzed the gene expression profiles of DT and DS leaves under osmotic stress of hydroponics induced by PEG-6000. Through differential analysis, we identified 1226 candidate unigenes, from which we subsequently screened out 115/212 differentially expressed genes (DEGs) that were more quickly induced/reduced in DT than in DS under osmotic stress. Among them, Unigene0005863 (EsSnRK2), Unigene0053902 (EsLRK10) and Unigene0031985 (EsCIPK5) may be involved in stomatal closure induced by abscisic acid (ABA) signaling pathway. Unigene0047636 (EsCER1) may positively regulates the synthesis of very-long-chain (VLC) alkanes in cuticular wax biosynthesis, influencing plant responses to abiotic stresses. Finally, the contents of wax and cutin were measured by GC–MS under osmotic stress of hydroponics induced by PEG-6000. Corresponding to RNA-seq, contents of wax monomers, especially alkanes and alcohols, showed significant induction by osmotic stress in DT but not in DS. It is suggested that limiting stomatal and cuticle transpiration under drought stress to maintain higher photosynthetic efficiency and water use efficiency (WUE) is one of the critical mechanisms that confer stronger drought resistance to DT. This study provides some insights into the molecular mechanisms underlying drought tolerance in E. sibiricus. The identified genes may provide a foundation for the selection and breeding of drought-tolerant crops.

Genome-Wide Identification of CAMTA Gene Family in Oat (Avena sativa) and Expression Analysis under Various Abiotic Stresses

Oat (Avena sativa) is one of the most important cereal crops and cool-season forage grasses in the world. The calmodulin-binding transcription activator (CAMTA) gene family is one of the largest families in plants, and it plays vital roles in multiple biological processes. However, the CAMTA genes in oats, especially those involved in abiotic stress, have not yet been elucidated. Herein, our findings reveal the presence of 20 distinct AsCAMTA genes, which were clustered into three subfamilies based on their gene structure and conserved motifs, indicating functional similarities within each subgroup. Chromosomal mapping indicated an uneven distribution across 10 chromosomes, suggesting a complex evolutionary history marked by potential gene duplication events. The results showed that most AsCAMTA genes contained stress-related cis-elements. The study further investigated the expression patterns of these genes under abiotic stress conditions utilizing RT-qPCR analysis. The results identified three AsCAMTA genes (AsCAMTA5, AsCAMTA7, and AsCAMTA19) that exhibited significant up-regulation under salt stress, with AsCAMTA7 also showing a marked increase in expression under drought stress. These findings suggest a pivotal role of AsCAMTA5, AsCAMTA7, and AsCAMTA19 genes in mediating the responses to various abiotic stresses by integrating multiple stress signals in oats. This investigation provides valuable insights into the potential functions of AsCAMTA genes in the stress response mechanisms of oats, laying a foundation for further functional studies aimed at enhancing abiotic stress tolerance in crops.

Selection environment impacts genetic gains for persistence in three temperate perennial forage grasses

Grasses and legumes are regularly grown in association, despite often being unbalanced or incompatible. This study was intended to conduct selection for persistence in three perennial grass species that have compatibility issues with alfalfa (Medicago sativa L.) or red clover (Trifolium pratense L.) and are poorly adapted to management-intensive rotational grazing. Five cycles of selection for persistence were conducted over a 24-year period for three grass species (reed canarygrass, smooth bromegrass, and timothy) in each of five selection environments: alfalfa mixture, red clover mixture, monocultures with a three-harvest hay management, tall fescue mixture with frequent defoliation, and monocultures with frequent defoliation. Selection in the two legume mixtures led to significant increases in persistence only when evaluated in legume mixtures. Selection responses were strongest when evaluated under the same legume as in the selection environment, indicating some species specificity. Selection for persistence under frequent defoliation was successful under both conditions (monoculture and tall fescue mixture), but led to no changes when evaluated with legumes. For these three grass species, cultivar development for use in mixture with legumes or for use in management-intensive rotational grazing should be based on a selection environment that mimics, as close as possible, the target production environment.

Effects of LAZY family genes on shoot gravitropism in Lotus japonicus

Plant architecture is an important agronomic trait to determine the biomass and sward structure of forage grass. The IGT family plays a pivotal role in plant gravitropism, encompassing both the gravitropic response and the modulation of plant architecture. We have previously shown that LjLAZY3, one of the IGT genes, plays a distinct role in root gravitropism in L. japonicus. However, the function of LAZY proteins on shoot gravitropism in this species is poorly understood. In this study, we identified nine IGT genes in the L. japonicus genome, which have been categorized into four clades based on the phylogenetic relationships of IGT proteins from 18 legumes: LAZY1, NGR (NEGATIVE GRAVITROPIC RESPONSE OF ROOTS), IGT-LIKE, and TAC1. We found that LAZY genes in the first three clades have demonstrated distinct role for modulating plant gravitropism in L. japonicus with specific impacts as follows. Mutation of the LAZY1 gene, LjLAZY1, defected the gravitropic response of hypocotyl without impacting the main stem's branch angle. In contrast, the overexpression of the NGR gene, LjLAZY3, substantially modulated the shoot's gravitropism, leading to narrower lateral branch angles. Additionally, it enhanced the shoots' gravitropic response. The overexpression of another NGR gene, LjLAZY4, specifically reduced the main stem's branch angle and decreased plant stature without affecting the shoot gravitropic response. The phenotype of IGT-LIKE gene LjLAZY2 overexpression is identical to that of LjLAZY4. While overexpression of the IGT-LIKE gene LjLAZY5 did not induce any observable changes in branch angle, plant height, or gravitropic response. Furthermore, the LjLAZYs were selectively interacted with different BRXL and RLD proteins, which should the important factor to determine their different functions in controlling organ architecture in L. japonicus. Our results deepen understanding of the LjLAZY family and its potential for plant architecture improvement in L. japonicus.

Green control for inhibiting Rhizopus oryzae growth by stress factors in forage grass factory.

The forage grass factory could break through the restrictions of land resources, region and climate to achieve efficient production throughout the year by accurate and intelligent management. However, due to its closed environment, mold outbreaks in the forage grass factory were severe, significantly affecting barley production. In this study, 9 contaminated barley tissues were collected and 45 strains were isolated in forage grass factory. After ITS sequencing, 45 strains were all identified as Rhizopus oryzae. Through stress factor assays, R. oryzae growth was seriously hindered by low concentration of sodium nitrate, high pH value and ozone water treatment. High pH and ozone water affected growth mainly by altering membrane integrity of R. oryzae. Sodium nitrate inhibited the growth of R. oryzae mainly by affecting the amount of sporulation. Low concentration of sodium nitrate and ozone water did not affect the growth of barley. High concentrations of sodium nitrate (100 mM) and pH values (8-8.5) inhibited barley growth. Among them, ozone water had the most obvious inhibition effect on R. oryzae. Large-scale ozone water treatment in the forage grass factory had also played a role in restoring barley production. Taken together, the green techonology to control mold disease and maintain the safety of forage through different physicochemical methods was selected, which was of considerable application value in animal husbandry.

Diversity of ecotypes of five species of ryegrass from Northwestern Spain by phenotypic traits and microsatellites

BackgroundThe Agricultural Research Centre of Mabegondo (Xunta de Galicia, A Coruña, Spain) conserves one of the most important collections of phytogenetic resources of ecotypes and natural populations of grassland species from northwestern Spain, among them populations of ryegrass (Lolium spp.), one of the most cultivated forage grasses in the world. The objective of the present study was to evaluate the diversity among commercial cultivars and natural ryegrass populations with phenotypic traits and molecular markers.ResultsEleven polymorphic microsatellites loci were used to analyze 58 ecotypes and 10 cultivars (680 DNA samples in total) differentiating 673 genotypes. Two main groups were detected by the Structure analysis, one related to Lolium perenne and a second to Lolium multiflorum. The first group showed two subgroups and the second three. The cluster of L. multiflorum showed two subgroups not related with the third cluster including commercial varieties, one from the Canary Islands (with Lolium rigidum included) and a second one from northwestern Spain, which presented specific agromorphological characteristics, such as lower FES (number of days from 1 January, when three heads per plant were flowering per plot), CRE (growth in flowering, in g of dry matter), and AIN (number of inflorescences per plant).ConclusionsThis is the first time that a large amount of data on ryegrass from the Iberian Peninsula has been analyzed, obtaining a clear genetic differentiation of the autochthonous varieties from the commercial varieties analyzed. In addition, the genetic structure found in the ecotypes was related to the phenotypic variation analyzed. Being of interest in the conservation of biodiversity and in obtaining better adapted varieties of ryegrasses, due to their specific phenotypic traits, such as a lower FES, CRE and AIN.

Resistência de poáceas forrageiras ao Blissus pulchellus Montandon (Hemiptera: Blissidae)

ABSTRACT Chinch bugs [Blissus pulchellus Montandon (Hemiptera: Blissidae)] suck the phloem from susceptible forage grasses, injecting toxins that destroy plant vessels and compromise the flow of water and nutrients, leading to plant death. Thus, the aim of this study was to assess eight forage grasses for antixenosis resistance to B. pulchellus and compare the anatomical characteristics of leaf sheath tissue from resistant and susceptible species/cultivars. Experiments were conducted in a laboratory and greenhouse, using choice and no-choice tests with the following forage grasses: Urochloa ruziziensis, U. humidicola, U. brizantha ‘Piatã’, U. brizantha ‘Paiaguás’, U. brizantha ‘Marandu’, Panicum maximum ‘Mombaça’, P. maximum ‘Zuri’, and Andropogon gayanus. The oviposition results demonstrated that in the choice test there was a change in the stink bug’s behavior in relation to grasses four hours after infestation, with U. humidicola, P. maximum ‘Mombaça’ and ‘Zuri’, U. brizantha ‘Marandu’ and A. gayanus, proving to be less attractive to insects. It is concluded that U. humidicola, P. maximum ‘Mombaça’ and ‘Zuri’, U. brizantha ‘Marandu’, and A. gayanus are less attractive to B. pulchellus. A. gayanus and P. maximum ‘Mombaça’ and ‘Zuri’ showed non-preference resistance (antixenosis) to oviposition by B. pulchellus. The resistance of U. humidicola, P. maximum ‘Zuri’, and A. gayanus to B. pulchellus may be associated with greater compaction and lignification of the parenchyma and sclerenchyma cells of leaf sheaths.

Unraveling the forage productivity puzzle: Comparing fast and slow-growing grasses.

Functional traits are powerful tools for distinguishing between plants with different resource acquisition strategies. Fast-growing plants normally dominate resource-rich habitats and present trait values associated with high productivity, such as high specific leaf area (SLA), short leaf lifespan, and rapid leaf elongation rate (LER). In contrast, slow-growing species have a higher leaf weight ratio (LWR), leaf lifespan (LLS), and phyllochron, which are useful traits for survival in stressful and unfertile environments, but are normally thought to be incompatible with high productivity, even under fertile conditions. We tested the hypothesis that slow-growing forage grasses have demographic parameters (tiller population density and canopy density) that offset their slow individual traits, making them as productive as fast-growing species when grown in fertile soil. Species with contrasting growth strategies (Arrhenatherum elatius L. and Festuca arundinacea Schreb cv. Quantum II, fast and slow-growing species, respectively) were cultivated in 45 m2 field plots and subjected to the same cutting regime and nitrogen supply level. Functional traits and canopy attributes were continuously measured during 8 growing cycles after the establishment of the swards. A. elatius had higher SLA, LER, leaf senescence, and leaf appearance rates, whereas F. arundinacea had higher LLS and LWR values. Conversely, there were no differences in relative growth rate or forage accumulation. F. arundinacea was able to offset their plant functional traits, typically associated with slow-growing grasses, with some demographic parameter like higher tiller population density, allowing it to be as productive as the fast-growing A. elatius when both were grown in fertile soil. Therefore, we suggest cautionary use of traditional plant functional traits to explain and predict the annual productivity of slow-growing grasses.