Forage Grasses Research Articles

Whole-genome sequencing of allotetraploid bermudagrass reveals the origin of Cynodon and candidate genes for salt tolerance.

Bermudagrass (Cynodon dactylon) is a globally distributed, extensively used warm-season turf and forage grass with high tolerance to salinity and drought stress in alkaline environments. However, the origin of the species and genetic mechanisms for salinity tolerance in the species are basically unknown. Accordingly, we set out to study evolution divergence events in the Cynodon genome and to identify genes for salinity tolerance. We developed a 604.0 Mb chromosome-level polyploid genome sequence for bermudagrass 'A12359' (n = 18). The C. dactylon genome comprises 2 complete sets of homoeologous chromosomes, each with approximately 30 000 genes, and most genes are conserved as syntenic pairs. Phylogenetic study showed that the initial Cynodon species diverged from Oropetium thomaeum approximately 19.7-25.4 million years ago (Mya), the A and B subgenomes of C. dactylon diverged approximately 6.3-9.1 Mya, and the bermudagrass polyploidization event occurred 1.5 Mya on the African continent. Moreover, we identified 82 candidate genes associated with seven agronomic traits using a genome-wide association study, and three single-nucleotide polymorphisms were strongly associated with three salt resistance genes: RAP2-2, CNG channels, and F14D7.1. These genes may be associated with enhanced bermudagrass salt tolerance. These bermudagrass genomic resources, when integrated, may provide fundamental insights into evolution of diploid and tetraploid genomes and enhance the efficacy of comparative genomics in studying salt tolerance in Cynodon.

Physiological and Biochemical Responses of Melilotus albus to Saline and Alkaline Stresses

Sweet clover (Melilotus albus) is a high-quality leguminous forage grass with salinity tolerance, drought tolerance, and cold hardiness. We selected four varieties of sweet clover with different sensitivities (061898, 061930, No. 55 white flower, and Ningxia white flower) and analyzed the effects of different concentrations of three sodium salts (Na2CO3, NaHCO3, and NaCl) on their physiology and biochemistry responses. Growth and development indexes (such as germination rate, root length, shoot length), chlorophyll content, osmotic regulators (proline, soluble sugar), malondialdehyde (MDA), superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) were determined under saline–alkali stress. Seed germination and seedling growth of all four clover species were significantly inhibited under saline–alkali stress. During germination, seed germination rate, root length, and shoot length decreased with increasing saline and alkaline concentration. Under saline–alkali stress, chlorophyll content tended to increase and then decrease, cell damage and death increased, and malondialdehyde, soluble sugar, and proline content tended to increase and then decrease. Moreover, the activities of SOD, POD, and CAT all increased and then decreased. Under Na2CO3 stress, the decrease in chlorophyll content of the resistant variety 061898 was less than in the sensitive Ningxia white flower variety. As the concentrations of Na2CO3, NaHCO3, and NaCl increased, the maximum photochemical efficiency of PSII was significantly affected. The resistant 061898 is capable of maintaining higher photosynthetic efficiency. Furthermore, under treatments with the three kinds of saline–alkali solutions, cell damage and death for Ningxia white flower were greater than in 061898. For 061898, the increases in soluble sugar and proline content were greater and the increase in malondialdehyde content was less, while the antioxidant enzyme activities were higher than those in Ningxia white flower. All four sweet clover varieties had higher stress resistance with neutral than with alkaline salts. When stressed by medium to high saline–alkali concentrations, sweet clover seedlings had increased osmotic substance content, enhanced antioxidant enzyme activity, and regulated physiological metabolism. Additionally, sweet clovers regulated the expression of WRKY33, GH3, CYCD3, OXI1, MKK2, MYC2, JAZ, COI1, PYL, PP2C, TGA, and MPK3 to adapt to the saline–alkali environment and improve saline–alkali tolerance. Our analysis of the sweet clover salinity tolerance mechanism contributes to its further use and is of significant importance for addressing land salinization and promoting sustainable agricultural and pastoral practices in China.

Using Machine Learning Methods Combined with Vegetation Indices and Growth Indicators to Predict Seed Yield of Bromus inermis.

Smooth bromegrass (Bromus inermis) is a perennial, high-quality forage grass. However, its seed yield is influenced by agronomic practices, climatic conditions, and the growing year. The rapid and effective prediction of seed yield can assist growers in making informed production decisions and reducing agricultural risks. Our field trial design followed a completely randomized block design with four blocks and three nitrogen levels (0, 100, and 200 kg·N·ha-1) during 2022 and 2023. Data on the remote vegetation index (RVI), the normalized difference vegetation index (NDVI), the leaf nitrogen content (LNC), and the leaf area index (LAI) were collected at heading, anthesis, and milk stages. Multiple linear regression (MLR), support vector machine (SVM), and random forest (RF) regression models were utilized to predict seed yield. In 2022, the results indicated that nitrogen application provided a sufficiently large range of variation of seed yield (ranging from 45.79 to 379.45 kg ha⁻¹). Correlation analysis showed that the indices of the RVI, the NDVI, the LNC, and the LAI in 2022 presented significant positive correlation with seed yield, and the highest correlation coefficient was observed at the heading stage. The data from 2022 were utilized to formulate a predictive model for seed yield. The results suggested that utilizing data from the heading stage produced the best prediction performance. SVM and RF outperformed MLR in prediction, with RF demonstrating the highest performance (R2 = 0.75, RMSE = 51.93 kg ha-1, MAE = 29.43 kg ha-1, and MAPE = 0.17). Notably, the accuracy of predicting seed yield for the year 2023 using this model had decreased. Feature importance analysis of the RF model revealed that LNC was a crucial indicator for predicting smooth bromegrass seed yield. Further studies with an expanded dataset and integration of weather data are needed to improve the accuracy and generalizability of the model and adaptability for the growing year.

An improved chromosome-level genome assembly of perennial ryegrass (Lolium perenne L.).

This work is an update and extension of the previously published article "Ultralong Oxford Nanopore Reads Enable the Development of a Reference-Grade Perennial Ryegrass Genome Assembly" by Frei etal.The published genome assembly of the doubled haploid perennial ryegrass (Lolium perenne L.) genotype Kyuss (Kyuss v1.0) marked a milestone for forage grass research and breeding. However, order and orientation errors may exist in the pseudo-chromosomes of Kyuss, since barley (Hordeum vulgare L.), which diverged 30million years ago from perennial ryegrass, was used as the reference to scaffold Kyuss. To correct for structural errors possibly present in the published Kyuss assembly, we de novo assembled the genome again and generated 50-fold coverage high-throughput chromosome conformation capture (Hi-C) data to assist pseudo-chromosome construction. The resulting new chromosome-level assembly Kyuss v2.0 showed improved quality with high contiguity (contig N50 = 120Mb), high completeness (total BUSCO score = 99%), high base-level accuracy (QV = 50), and correct pseudo-chromosome structure (validated by Hi-C contact map). This new assembly will serve as a better reference genome for Lolium spp. and greatly benefit the forage and turf grass research community.

148 Supplementing Bovacillus to newly weaned beef steers during a 90-d grazing period

Abstract This experiment compared performance, health, and physiological responses of high-risk stocker cattle receiving a Bacillus subtilis derivative during a 90-d grazing period. Crossbred steers (n = 120) were obtained from an auction yard and transported to the experimental facility. Steer shrunk body weight (BW) was recorded at arrival (d -1). This value was averaged with BW recorded on d 0 to represent initial BW (236 ± 2 kg). On d 0, steers were ranked by BW and allocated to 1 of 12 pastures (4-ha pastures; 10 steers/pasture). Pastures were randomly assigned to receive daily supplementation with dried distillers’ grains at 1% of BW containing either: 1) Bacillus licheniformis and B. subtilis ingredient (BOV; 2 g/steer daily of Bovacillus, Chr Hansen A/S, Horsholm, Denmark) or 2) no additive (CON). Cattle received treatments from d 0 to 90 while housed in pastures containing stockpiled grass forage, as well as free-choice access to water and a commercial mineral + vitamin mix without ionophores. Steers were assessed for bovine respiratory disease (BRD) signs daily, and shrunk BW recorded on d 91. Blood samples were collected, and BW recorded on d 0, 14, 28, 56, and 90. No treatment differences were detected (P ≥ 0.19) for glucose, non-esterified fatty acids, β-hydroxybutyrate, haptoglobin, or insulin-like growth factor 1, whereas a treatment × day interaction indicated increased cortisol in BOV cattle on d 56 (P < 0.01). A treatment × day interaction was detected for serum concentrations of parainfluenza type 3 antibodies, which was greater in BOV steers on d 90 (P < 0.01). No treatment differences were detected (P ≥ 0.23) for serum concentrations of antibodies against other BRD pathogen. Average daily gain (ADG) tended to be increased (P = 0.09) in BOV compared with CON steers from d 56 to d 90 (0.858 and 0.760 kg/d, respectively, although did not impact overall ADG (P = 0.48). No treatment differences were detected for steer final BW (P = 0.43). Total BW change per pasture was greater in BOV compared with CON (790 vs. 550 kg BW change; P = 0.02). No treatment differences were detected (P = 1.00) for BRD incidence, although steers removed from the experiment for health reasons tended to be increased in CON compared with BOV (P = 0.08). Despite lacking differences in health or physiological responses, B. licheniformis and B. subtilis supplementation increased overall production of BW in high-risk stocker steers during a 90-d grazing period.

Doubled haploidy methodology for three forage grasses [crested wheatgrass (Agropyron cristatum (L.) Gaertn.), hybrid bromegrass (Bromus riparius x B. inermis), and meadow bromegrass (Bromus riparius Rehm.)

Doubled haploidy (DH) methodology is used in many plant species to accelerate crop improvement and cultivar development; however not all species are amenable to the tissue culture technique. Experiments were undertaken to develop DH protocols for three perennial grasses [crested wheatgrass (Agropyron cristatum (L.) Gaertn.), hybrid bromegrass (Bromus riparius x B. inermis), and meadow bromegrass (Bromus riparius Rehm.)]. The initial experiment screened these forage grass species to established wheat (Triticum aestivum L.) microspore culture protocols. Following the initial screen, several factors influencing microspore embryogenesis were evaluated. These included genotype, donor plant conditions, developmental stage of the microspore, pretreatments, media composition, and culture conditions. For regeneration of the embryos to plants, media composition and culture conditions were assessed. Microspore-derived embryos/calli as well as green haploid/doubled haploid plants were regenerated from all three forage grasses. Differences were observed between species and genotypes within species in terms of embryogenic response. Modifications to the initial wheat DH protocol included the donor plant conditions, developmental stage of the microspore to late uninucleate to early binucleate and media composition. Regenerated plants were grown in the greenhouse.

Yield Potential and Quality of Egyptian Clover Intercropped with Forage Grasses

Yield Potential and Quality of Egyptian Clover Intercropped with Forage Grasses

Historical and ecological aspects of hydro-reclamation research at the Kirov Meadow-Swamp Experimental Station (<i>to the 105th anniversary of the Station's formation</i>)

The article presents the history of the origin and development of hydromodule research at the Kirov Meadow-Swamp Experimental Station, their practical implementation and ecological significance in the development of the principles of a saving, soil-protective and environment-forming system of agriculture on organic soils in the conditions of the North-East of the European part of the Russian Federation. The main object of long-term research is a typical lowland peatland «Gadovskoye», located on the territory of the Kotelnich peat base of the Kirov region. Special attention is paid to the search for the most effective ways to regulate the water regime of drained swamps used in feed production. It has been established that the most operational, efficient and environmentally friendly method is sluicing, when additional moisture is supplied to the root layer from below. The most optimal range of groundwater regime for annual and perennial forage grasses is shown. The correlation dependence of yield on the degree of drainage of peat deposits is presented. A significant contribution to the reclamation science was made by hydromodule studies on the cutover bogs of the Kirov region. The chemical composition of groundwater and waste swamp waters has been studied on the «Gadovskoye», «Zenginskoye», «Bakhtinskoye», «Pishchalskoye» peatlands, and others, the relationship of the water-physical properties and water regime of the residual deposit with food and temperature regimes, as well as with the coefficient of water consumption of plants and the bearing capacity of the soil of cutover bogs has been established. Agroecological monitoring of the developed peatlands, which have been in culture for more than 40−60 years, shows that during the operation of these facilities there is a gradual decrease in their productivity, due to a decrease in the total agricultural background, partial and even complete violation of the hydrological functions of the drainage network. In order not to completely lose these anthropogenic formations from the sphere of cultural nature management, it is necessary, first of all, periodic repairs of the entire drainage system. Further restructuring within the landscape shell will make it possible to construct fundamentally new post-swamp forest-meadow agroecosystems, where other alternative fields to forage production (hunting, forestry activity, berry-officinal, mushroom, etc.) can be provided.

High-resolution bulked segregant analysis enables candidate gene identification for bacterial wilt resistance in Italian ryegrass (Lolium multiflorum Lam.).

Bacterial wilt, caused by Xanthomonas translucens pv. graminis (Xtg), is a serious disease of economically important forage grasses, including Italian ryegrass (Lolium multiflorum Lam.). A major QTL for resistance to Xtg was previously identified, but the precise location as well as the genetic factors underlying the resistance are yet to be determined. To this end, we applied a bulked segregant analysis (BSA) approach, using whole-genome deep sequencing of pools of the most resistant and most susceptible individuals of a large (n = 7484) biparental F2 population segregating for resistance to Xtg. Using chromosome-level genome assemblies as references, we were able to define a ~300 kb region highly associated with resistance on pseudo-chromosome 4. Further investigation of this region revealed multiple genes with a known role in disease resistance, including genes encoding for Pik2-like disease resistance proteins, cysteine-rich kinases, and RGA4- and RGA5-like disease resistance proteins. Investigation of allele frequencies in the pools and comparative genome analysis in the grandparents of the F2 population revealed that some of these genes contain variants with allele frequencies that correspond to the expected heterozygosity in the resistant grandparent. This study emphasizes the efficacy of combining BSA studies in very large populations with whole genome deep sequencing and high-quality genome assemblies to pinpoint regions associated with a binary trait of interest and accurately define a small set of candidate genes. Furthermore, markers identified in this region hold significant potential for marker-assisted breeding strategies to breed resistance to Xtg in Italian ryegrass cultivars more efficiently.

Justification of the Unit Design Diagram for Mowing Agricultural Crops Simultaneously with Their Stuble Chopping

Abstract The two-phase method is quite widespread when harvesting grain crops and forage grasses. For its implementation, farmers prefer harvesting units with a front-mounted header. The main disadvantage of such units is that after their passage in the space between the swaths of mown crops, open soil falls under the direct influence of sunlight. Subsequently, this leads to an intensive loss of its moisture. A harvesting unit has been designed to eliminate this shortcoming, consisting of a tractor with a front harvester and a soil-cultivating machine (disc harrow) mounted at the rear. The latter chops stubble and soil in the space between the swaths of the mowed crop, contributing to soil moisture conservation. In the diagram plan, the tillage machine can have a swivel or fixed conjunction with the tractor in a horizontal plane. A mathematical model of the harvesting unit plane-parallel movement in the horizontal plane has been designed to choose these conjunctions better. In the study, it is used to analyze the corresponding amplitude (AFC) and phase (PFC) frequency characteristics of a dynamic system when it is working out a control action in the form of the sighting point transverse shift. As a mathematical modeling result, it was found that the fixed conjunction of a tillage machine with a tractor is preferable. In this case, the natural AFC practically approaches the perfect one for servo dynamical systems. The correlation degree between the tractor‘s steered wheels‘ rotation and heading angles increases by almost 37%. As a result, this leads to a significant decrease in this parameter variance fluctuations, which contributes to an increase in the harvesting unit controllability movement as a whole.

Phylogenomic analysis reveals five independently evolved African forage grass clades in the genus Urochloa.

The grass genus Urochloa (Brachiaria) sensu lato includes forage crops that are important for beef and dairy industries in tropical and sub-tropical Africa, South America and Oceania/Australia. Economically important species include U. brizantha, U. decumbens, U. humidicola, U. mutica, U. arrecta, U. trichopus, U. mosambicensis and Megathyrsus maximus, all native to the African continent. Perennial growth habits, large, fast growing palatable leaves, intra- and interspecific morphological variability, apomictic reproductive systems and frequent polyploidy are widely shared within the genus. The combination of these traits probably favoured the selection for forage domestication and weediness, but trait emergence across Urochloa cannot be modelled, as a robust phylogenetic assessment of the genus has not been conducted. We aim to produce a phylogeny for Urochloa that includes all important forage species, and identify their closest wild relatives (crop wild relatives). Finally, we will use our phylogeny and available trait data to infer the ancestral states of important forage traits across Urochloa s.l. and model the evolution of forage syndromes across the genus. Using a target enrichment sequencing approach (Angiosperm 353), we inferred a species-level phylogeny for Urochloa s.l., encompassing 54 species (~40 % of the genus) and outgroups. Phylogenies were inferred using a multispecies coalescent model and maximum likelihood method. We determined the phylogenetic placement of agriculturally important species and identified their closest wild relatives, or crop wild relatives, based on well-supported monophyly. Further, we mapped key traits associated with Urochloa forage crops to the species tree and estimated ancestral states for forage traits along branch lengths for continuous traits and at ancestral nodes in discrete traits. Agricultural species belong to five independent clades, including U. brizantha and U. decumbens lying in a previously defined species complex. Crop wild relatives were identified for these clades supporting previous sub-generic groupings in Urochloa based on morphology. Using ancestral trait estimation models, we find that five morphological traits that correlate with forage potential (perennial growth habits, culm height, leaf size, a winged rachis and large seeds) independently evolved in forage clades. Urochloa s.l. is a highly diverse genus that contains numerous species with agricultural potential, including crop wild relatives that are currently underexploited. All forage species and their crop wild relatives naturally occur on the African continent and their conservation across their native distributions is essential. Genomic and phenotypic diversity in forage clade species and their wild relatives need to be better assessed both to develop conservation strategies and to exploit the diversity in the genus for improved sustainability in Urochloa cultivar production.

Successional changes in bacterial phyllosphere communities are plant-host species dependent.

Leaf surface microbiomes have the potential to influence agricultural and ecosystem productivity. We assessed their stability by determining composition, functional resistance, and resilience. Resistance is the degree to which communities remain unchanged as a result of disturbance, and resilience is the ability of a community to recover to pre-disturbance conditions. By understanding the mechanisms of community assembly and how they relate to the resistance and resilience of microbial communities under common environmental stresses such as drought, we can better understand how communities will adapt to a changing environment and how we can promote healthy agricultural microbiomes. In this study, phyllosphere compositional stability was highly related to plant host species phylogeny and, to a lesser extent, known stress tolerances. Phyllosphere community assembly and stability are a result of complex interactions of ecological processes that are differentially imposed by host species.

A Transcriptome Reveals the Mechanism of Nitrogen Regulation in Tillering.

Nitrogen (N) application significantly increases tiller numbers and is accompanied by changes in endogenous hormone content. We treated seedlings of Festuca kirilowii-a perennial forage grass-with nitrogen, determined the endogenous hormone content in the tiller buds, and performed a transcriptome analysis. The application of N reduced GA3, ABA, and 5-DS content and increased ZT and IAA content. By screening DEGs in the transcriptome results, we obtained DEGs annotated to 25 GO entries and 8 KEGG pathways associated with endogenous hormones. Most of these GO entries and KEGG pathways were associated with IAA, GAS, and ABA. We conducted a validation analysis of hormone-related DEGs using qRT-PCR to demonstrate that nitrogen controls the content of endogenous hormones by regulating the expression of these DEGs, which further affects tillering in F. kirilowii.

Can permanent grassland soils with elevated organic carbon buffer negative effects of more persistent precipitation regimes on forage grass performance?

Agricultural practices enhancing soil organic carbon (SOC) show potential to buffer negative effects of climate change on forage grass performance. We tested this by subjecting five forage grass varieties differing in fodder quality and drought/flooding resistance to increased persistence in summer precipitation regimes (PR) across sandy and sandy-loam soils from either permanent (high SOC) or temporary grasslands (low SOC) in adjacent parcels. Over the course of two consecutive summers, monoculture mesocosms were subjected to rainy/dry weather alternation either every 3 days or every 30 days, whilst keeping total precipitation equal. Increased PR persistence induced species-specific drought damage and productivity declines. Soils from permanent grasslands with elevated SOC buffered plant quality, but buffering effects of SOC on drought damage, nutrient availability and yield differed between texture classes. In the more persistent PR, Festuca arundinacea FERMINA was the most productive species but had the lowest quality under both ample water supply and mild soil drought, whilst under the most intense soil droughts, Festulolium FESTILO maintained the highest yields. The hybrid Lolium × boucheanum kunth MELCOMBI had intermediate productivity and both Lolium perenne varieties showed the lowest yields under soil drought, but the highest forage quality (especially the tetraploid variety MELFORCE). Performance varied with plant maturity stage and across seasons/years and was driven by altered water and nutrient availability and related nitrogen nutrition among species during drought and upon rewetting. Moreover, whilst permanent grassland soils showed the most consistent positive effects on plant performance, their available water capacity also declined under increased PR persistence. We conclude that permanent grassland soils with historically elevated SOC likely buffer negative effects of increasing summer weather persistence on forage grass performance, but may also be more sensitive to degradation under climate change.

PRODUKSI DAN KANDUNGAN NUTRIEN HIJAUAN RUMPUT Pennisetum purpureum cv Mott, DENGAN PEMBERIAN PUPUK ORGANIK CAIR HASIL VERMICOMPOSTING LIMBAH SAPI POTONG

Fertilization is a very important effort for Dwarf Elephant Grass (Pennisetum purpureum cv Mott) to achieve forage production and high nutritional quality following its potential. This research aims to determine the yield of dry matter, crude protein content, and crude fiber of Dwarf Elephant Grass by application of liquid organic fertilizer (LOF) resulting from vermicomposting of beef cattle waste. The research was conducted at the Field Laboratory of Forage Crop, and the Ruminant Animal Nutrition and Feed Chemistry Laboratory, Faculty of Animal Husbandry, Padjadjaran University from January to June 2018. The research method used was the experimental method with a Completely Randomized Design using 3 treatments, namely P1 (5,000 L per Ha), P2 (10,000 L per Ha), and P3 (15,000 L per Ha), and 6 replications. Data were processed by analysis of variance and continued with Duncan's Multiple Range Test. The results showed that giving LOF increased the production, increased the content of crude protein, and decreased the crude fiber content of Dwarf Elephant Grass forage. Giving LOF from vermicomposting beef cattle waste at a dose of 15,000 L per Ha resulted in the highest forage dry matter yield (1,925 kg per Ha), one-time cutting at dry season, and the best nutrient content seen from the crude protein content (13.95%) and crude fiber content (28.53%).

Mathematical models for predicting protodioscin in tropical forage grasses

Protodioscin is a saponin present in grasses that can lead to losses in animal production. Our hypothesis was that mathematical models can accurately and precisely predict the protodioscin concentration in tropical grasses. We evaluated the ability of four mathematical models to describe the protodioscin concentration in Brachiaria and Panicum cultivars with different regrowth periods. Six cultivars of Panicum: Aruana, Massai, Mombaça, Tanzânia, Tamani, and Zuri; and five of Brachiaria-grass: Marandu, Paiaguás, Piatã, Xaraés and Basilisk. Protodioscin concentration evaluations were carried out at 51, 84, 110, and 111 days of age. Linear, Quadratic, Exponential, and Logarithmic models were evaluated, and the adequacy of the models was verified. The models were compared for accuracy and precision by pairwise mean squared error analysis and the delta Akaike information criterion. The models did not differ from each other in terms of accuracy and precision. The exponential model showed a high ability to explain the observed variability between protodioscin concentration and plant age for Brachiaria grasses. Panicum grasses have constant protodioscin concentration. Mathematical models are capable of predicting the protodioscin concentration in grasses of the genus Brachiaria based on plant age. We recommend Exponential model to predict the concentration of protodioscin in Brachiaria grasses.

Evaluation of in situ and ex situ forage germplasm collections reveals the first occurrence and seed-transmission of alfalfa mosaic virus and southern bean mosaic virus in Urochloa species

Grasses of the genus Urochloa (Urochloa species syn. Brachiaria species) are among the most important tropical forage grasses of African origin. The International Livestock Research Institute (ILRI) Forage Genebank maintains 671 Urochloa grass accessions, belonging to 28 species, of which 261 (39%) accessions are Urochloa brizantha (A.Rich.) R.D.Webster. The susceptibility of Urochloa grasses to disease and insect pests is a key challenge to the sustainable production of these grasses in Africa. In this study, using a dot blot assay and RT-PCR, we report for the first time the association of Alfalfa Mosaic Virus (AMV) and Southern Bean Mosaic Virus (SBMV) with 92% of the tested accessions conserved in situ and ex situ in the ILRI forage genebank. In addition, virus transmission from seed to plant and from legume to grass was confirmed through the bioassay test. The detection of these two viruses in Urochloa species presents a new challenge to germplasm conservation, distribution, and their sustainable production in the region, and demands immediate attention towards developing an effective method of cleaning viruses from the conserved germplasm. Furthermore, there is an urgent need to assess the economic importance of diseases in the grasses, and for the selection of germplasm that shows resistance to diseases.

Tolerance of Forage Grass to Abiotic Stresses by Melatonin Application: Effects, Mechanisms, and Progresses

Climate change related abiotic stress has been potentially impacting the quantity and quality of forage grass. Melatonin, a multifunctional molecule that has been found to be present in all plants examined to date, plays a crucial role in improving forage grass tolerance to both biotic and abiotic stresses. However, research on melatonin’s role in forage grass is still developing. In this review, the effects of melatonin application on abiotic stress are the primary topic, and we try to find relative mechanisms. In order to determine whether melatonin has a good effect on forage grass, we compared and summarized the adapting ability of different forage grasses under abiotic stress after melatonin application in aspects of growth and development, photosynthesis, antioxidant systems, plant hormone interactions, and ion homeostasis. According to part of the data, we found that different forage grasses exhibited varying responses to endogenous melatonin content and exogenous melatonin dose applications. Meanwhile, the regulatory mechanisms of melatonin application include the expression of chlorophyll synthesis and degradation genes, electron transport and phosphorylation genes, stress regulation pathway genes, and plant hormone synthesis genes. We propose possible future studies that can further explore the metabolic pathways of melatonin and the molecular mechanisms of melatonin regulation of abiotic stress in forage grass. Specifically, research can focus on elucidating the signaling pathways, gene expression of regulatory networks, and interactions with other plant hormones. This will provide valuable theoretical and practical guidance for adapting to climate change and forage grass development.

Optimum Seed Harvest Time of Trifolium lupinaster L. in Relation to Flowering, Pods and Seed Characteristics

Background: Pod splitting is the main cause of the low seed yield of legume forage grasses. In the present study, the flowering pattern, seed maturity characteristics and the optimum seed harvesting time of Trifolium lupinaster L. were investigated to improve seed yield and quality. Methods: All the required observations for this study were completed in the new line nursery from July to October 2022. Flowering habits of populations, individual plants, inflorescences and florets were observed for two consecutive months from July 1 to September 1 and daily temperatures and humidity were recorded.Observations on the state of seed and pod development were made by sampling and measuring in three batches every three days from July 25 to August 23 starting from the 12th day after the first flower and continuing until the first day of the season. Starting from July 15, seed yield and constitutive factors were measured every 10 d until September 5th. Result: The results showed that the flowering period of T. lupinaster L. population lasted for 60 days and the peak opening period was on the 11th-20th day after heading began, the florets opened most vigorously at 11:00-13:00 every day and inflorescences were opened more vigorously at 15:00 every day. The opening pattern of florets and inflorescences was greatly affected by temperature and humidity. The fresh weight of pod skin and seeds reached the maximum on the 15th day after flowering; the length and width of pods and seeds reached the maximum on the 18th day; the water content of pod skin and seeds began to decrease sharply on the 21st day, while the pods began to crack and the surface of the seeds dried and hardened; the water content of seeds decreased to below the safe storage moisture at 27 days. Our resuts showed that mid-August was the optimum seed harvesting period for T. lupinaster L.

Yield and quality responses of Megathyrsus maximus and Cynodon spp. forage grasses to irrigation

Periodic variations in rainfall have resulted in longer periods of drought in traditional rainfed livestock systems on savanna areas in Brazil. However, irrigation management techniques and rotational grazing have improved the productivity of these systems by mitigating soil water stress on forage grasses. The objectives of this research were to evaluate the response of Megathyrsus maximus cv. Tanzania and Cynodon spp. cv. Tifton 85 (Cynodon nlemfuensis × Cynodon dactylon) forage grasses to irrigation, and to determine their irrigation water productivity (IWP). The experiment was conducted at the University of São Paulo in Brazil. Plant height (PH), dry matter (DM), crude protein (CP), neutral detergent fiber (NDF) and acid detergent fiber (ADF) were measured, and IWP was calculated. Tifton 85 had a higher CP content than Tanzania but a lower average DM yield. The irrigation management (IM) treatments did not influence CP levels of both forage grasses, but in most situations, did affect their average DM yield. The IWP of Tanzania and Tifton 85 forage grasses did not differ among irrigation management treatments.