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Crop irrigation requirements are usually estimated based on crop evapotranspiration (ETc) as determined by the reference evapotranspiration (ETo) and crop coefficient (Kc). There is a lack of knowledge on the irrigation requirements of tropical forage crops in Brazil, contrasting with the increasing use of irrigation in pastures. The effort of this study was to investigate what would be the water needs of tropical forages in Southern Brazil, based on a robust experimental database. The study was carried out in São Paulo State-Brazil using different forages species and their combinations [Guinea grass (GG); Guinea grass + black oat + ryegrass (GOR); Bermuda grass (BG), and Bermuda + black oat + ryegrass (BOR)]. The experimental fields were fully irrigated, and the Kc values were derived from ETc measurements on lysimeters; ETo was estimated using daily data from a nearby weather station and the standard FAO56 parameterization. Mean daily ETc values for GG, GOR, BG and BOR were 4.1, 2.9, 3.6, and 3.4 mm, respectively, and respective mean Kc values were 0.99, 0.90, 1.0, and 0.94. Average Kc values for all plots decreased as ETo increased, producing a negative Kc-ETo relationship, mainly when ETo reached values greater than 5 mm d−1. This was most likely due to internal plant stomatal resistance to vapor release from the leaves diffusing to the atmosphere at high ETo. So, the time-based Kc curves described by FAO 56 manual should be adjusted for the analyzed crops considering different ranges of ETo to improve the required irrigation depth. [ABSTRACT FROM AUTHOR]

Sandy soil is typically poor in organic matter. When areas with sandy soil are used for pasture prior to soybean cultivation, the availability of nitrogen (N) for plants is limited even further. Our objective was to evaluate if inoculation combined with N fertilization increases N content in the soil and N supply to soybean plants in post-pasture and post-soybean areas. Four experiments were conducted in degraded post-pasture and post-soybean areas in a sandy soil (Rhodustult), between 2016 and 2018, in Brazil. Treatments used a combination of inoculant (zero, 4, 8 and 12 rates ha−1) and mineral N (0, 25, 50, and 100 kg ha−1) with four replicates. It was using the soybean cultivar TMG 7062 IPRO. The post-soybean area had higher N content in the soil than the post-pasture area; 33, 32, and 21% for total N, microbial biomass nitrogen (MBN), and inorganic nitrogen (IN), respectively. Soybean shoots from the post-soybean area also had greater accumulations of N (86 kg ha−1 of N). Increased N fertilization linearly raised levels of N in the soil (total N, MBN, and IN). In both areas, the effect of inoculation was restricted by the increase of total N in the soil. Inoculation combined with moderate rates of N in soybeans (50 kg ha−1) increased levels of N in the soil and N supply to plants in post-pasture areas. In post-soybean areas, inoculation alone fulfilled the N soybean need. [ABSTRACT FROM AUTHOR]

We evaluated Italian ryegrass (Lolium multiflorum Lam.) establishment in a factorial of grazing intensity (intense, moderate, moderate‐light, light, and no grazing, with target average sward heights of 10, 20, 30, and 40 cm in the grazed plots) and additional seeding (self‐seeding with or without additional seeding) in an integrated soybean‐beef cattle system in southern Brazil. Grazing treatments were imposed in winter (June–July) and followed by a direct‐seeded soybean crop (November). The establishment was quantified prior to the stocking periods in 2017 and 2018, corresponding to self‐seeding from 2016 and 2017. Intense grazing impaired ryegrass re‐establishment, resulting in larger individual plants (0.54 vs. 0.15 g dry matter plant−1) but lower population density (57 vs. 1,355 plants m−2) than in the other treatments. Additional broadcast ryegrass seeding did not fully compensate for the reduced natural reseeding in this treatment. The addition of seeds under intense grazing increased plant population density to values comparable to moderate grazing intensities but reduced individual plant mass, limiting herbage mass attained by the end of the pasture establishment phase. Contrastingly, the various combinations of individual plant mass and population density were sufficient to maintain herbage masses in moderate to light grazing intensities that were comparable to that in the ungrazed treatment, regardless of seed addition (63 vs. 180 g DM m−2 for intense grazing vs. the average of other treatments over the whole establishment phase). Moderate grazing, e.g., target sward heights of 20 cm or greater, is necessary to achieve a system that can sustain itself without seed addition. [ABSTRACT FROM AUTHOR]

Ryegrass (Lolium multiflorum Lam.) is one of the most difficult annual weeds to control in cultivation systems worldwide, especially in temperate regions. The widespread use of herbicides in the past two decades has selected resistant biotypes of ryegrass in crops in Southern Brazil. Ryegrass seeds are dormant when disseminated and germination can be staggered over time (crop‐growing season). Knowledge of the germination behavior of seeds from herbicide‐resistant plants has been little studied, but it would be very useful in integrated weed management. Thus, this study aimed to characterize the dynamics of the soil seed bank of two biotypes of L. multiflorum, one glyphosate‐resistant and the other glyphosate‐susceptible, under a no‐tillage system. The treatments were arranged in a bifactorial scheme, using seeds from biotypes (glyphosate‐resistant and glyphosate‐susceptible) with monthly periods of removal from field (one to 12 months). Seeds of each biotype were placed on the soil surface and covered with soil and straw to simulate no‐till conditions. The percentage of germinated, dormant, and dead seeds was evaluated every 30 days. The ryegrass seed bank of glyphosate‐susceptible and glyphosate‐resistant biotypes was reduced to 11 and 15% of dormant seeds, respectively, at the end of 12 months. However, there was no variation in germination, dormancy, and seed mortality between susceptible and glyphosate‐resistant ryegrass. Seeds of glyphosate‐resistant biotype and susceptible showed germination behavior with similar dynamics in the soil over a period of 12 months. [ABSTRACT FROM AUTHOR]

No‐tillage farming combined with temporary cattle grazing is becoming a common practice in parts of South America. We quantified the effects of no‐tillage and winter grazing of annual ryegrass (Lolium multiflorum Lam.) on soil carbon and nitrogen stock, stratification ratio (concentration in 0–5 to 10–20‐cm layer) and lability (based on particulate organic matter, POM), relative to conventional tillage or ungrazed ryegrass. A 9‐year‐old experiment was conducted in a southern Brazilian Ferralsol. Soil under no‐tillage accumulated 1.11 Mg C ha−1 year−1 and 0.10 Mg N ha−1 year−1 to 100‐cm depth relative to conventional tillage when ryegrass was not grazed, and also increased the stratification ratio of carbon (1.48 vs. 1.11) and nitrogen (1.66 vs. 1.17). The carbon and nitrogen lability was also greater in no‐tillage soil, as carbon and nitrogen stocks increased proportionally more in sand‐POM than in silt or clay size fractions (carbon lability index = 1.57 vs. 1.00; nitrogen lability index = 1.57 vs. 1.00). Semiquinone concentrations in physical fractions were 4–28% smaller in no‐tillage, suggesting less organic matter aromaticity in this treatment. Grazing, however, caused no further improvement of stocks of carbon and nitrogen in the 0–100‐cm layer of no‐tillage soil (e.g., 209 vs. 212 Mg C ha−1, ns), or enhancement of stratification or lability of those elements, relative to ungrazed ryegrass. Overall, no‐tillage effectively promoted soil carbon and nitrogen accumulation and lability in this subtropical Ferralsol, whereas grazing did not compromise the gains of no‐tillage. Highlights: Capacity of no‐tillage and grazing to enhance stocks, stratification and lability of soil C and N.C sequestration with no‐tillage is being debated, and little is known when combined with grazing.No‐tillage accumulated 1.11 Mg C ha−1 year−1 but grazing promoted no further C accumulation.No‐tillage effectively accumulated C in soil and grazing did not compromise such gain of no‐tillage. [ABSTRACT FROM AUTHOR]

The objective of this work was to determine the effect of desiccation and haymaking periods in the off-season on the quality of hay produced and nutrient accumulation, as well as to quantify the effects of remaining dry mass on the establishment and development of soybean in lowland areas. The experiment was conducted in the field in the 2015/16 and 2016/17 growing season in the lowland area of the Federal University of Santa Maria, Rio Grande do Sul, Brazil. Two treatments of ryegrass management (hay and desiccation) in five periods and one fallow period were tested. The study implemented an experimental randomized block design. The following variables were measured in the off-season: ryegrass dry shoot mass, hay quality parameters, moisture and nutrient content in the soil. In addition, the initial population of plants, dry shoot mass, nodule dry mass and grain yield were determined in the soybean. The cultivation of ryegrass hay in lowland area is a viable alternative. However, it reduces the potassium content in the soil if it is not replaced by fertilization. The use of ryegrass, regardless of the period of haymaking or desiccation, increases the water retention in the soil, which promotes straw wrapping and/or mirroring of the soil in a year of elevated precipitation, with a consequent reduction of the initial plant population and soybean grain yield when compared to the fallow system. [ABSTRACT FROM AUTHOR]

The barley culture has been conquering space in Southern Brazil, being an option for rotation with wheat. One of the main constraints for the increased productivity is the race against weed, especially ryegrass. Therefore, this study aimed to evaluate the barley competitive ability (Hordeum vulgare) against the ryegrass (Lolium multiflorum), in relation to the nitrogen absorption and to measure the density in which the culture is negatively affected. For this, a field experiment was conducted using experimental designs of randomized blocks, where the barley coexisted with different ryegrass densities (0, 4, 16, 32, 64 and 128 m-2). The analyzed varieties were plant height, chlorophyll, number of barley and ryegrass stems, barley and ryegrass dry mass, leaf area, number of spikes, number of grains per spike, the weight of a thousand grains and yield. The ryegrass interferes negatively on the barley's development and productivity, even in low densities, being necessary its control to four plants m-2. [ABSTRACT FROM AUTHOR]

Integrated Crop Livestock Systems (ICLS) are important alternative for diversification and sustainable food production, while conserving soil. The effects on soil structure of adopting ICLS in lowlands are widely unknown. Our hypothesis was that the adoption of ICLS, in lowland production systems for flooded-irrigation rice cultivation, improves the structure and functionality of the porous soil system, mainly stimulated by the increased root growth from pastures. The objective was to investigate how different managements of integrated systems in lowlands influence the structure and quality of a Planosol in southern Brazil. The evaluation was carried out between the fifth and sixth year of an experiment consisting of four agricultural production systems, based on irrigated rice cultivation, in a randomized block design with three replications. The systems were RFR-ct: rice – fallow – rice, without animal grazing in winter and with soil disturbance (conventional tillage) in the spring; RGrR-nt: rice - grazed ryegrass - rice, with no till; RGrSGrR-nt: rice - grazed ryegrass - soy - grazed ryegrass - rice, with no till; e P4R-nt: pasture (ryegrass + white clover + birdsfoot trefoil) in winter, and succession field in the summer, being continuously grazed and cultivated with rice under no-tillage every four years. Samples with preserved structure were collected at three seasons: after the grazing cycle (spring 2018), after harvesting the summer crops (fall 2019), and after another grazing cycle (spring 2019). Soil bulk density, total porosity, macroporosity, microporosity, water retention curve, pore size distribution, porosity and organic material by computed tomography (CT), and root biomass were determined. The results indicated that the ICLS, even without tillage and with animal trampling, kept the same physical condition as tilled system, and the system with rice in succession to ryegrass increased available water. Thus, soil tillage as a strategy to improve its physical structure is unjustifiable. The CT revealed that periodic tillage forms spherical, poorly connected pores, while root growth in ICLS created a continuous, connected porosity. Therefore, similar physical properties do not correspond to equal soil structure and functionality. Presence of organic material in the soil, roots or crop residues are crucial to porosity maintenance in all systems. • Similar bulk soil properties may produce dissimilar soil functionality. • Animal trampling in ICLS in lowlands did not increase topsoil bulk density. • Cover in ICLS plays an important soil structure protective role in loamy soils. • Root growth of grasses in ICLS promotes a continuous, connected porosity. • Periodic tillage in lowlands forms spherical, poorly connected pores. [ABSTRACT FROM AUTHOR]

The fertilization in rangelands has a positive effect in the forage production. The increased nitrogen (N) availability improves plant growth and forage quality of native pastures. However, in the Pampa biome conditions of Rio Grande do Sul State, Brazil, these responses occur surprisingly fast and consistently. Therefore, the objective of this work was to quantify the N effect in the botanical composition of a natural pasture overseeded with annual ryegrass in Southern Brazil. The effects of three rates of N fertilization (zero, 100 and 200 kg N ha-1) were evaluated. Forage biomass was estimated on a monthly basis using the double sampling approach. The different botanical components of each forage sample were manually sorted in the laboratory. In order to calculate the Rényi diversity profile, two floristic composition evaluations were performed in the experimental area in December of 2010 and September of 2011. The ryegrass biomass production is highly affected by the N fertilization. The botanical composition of natural pastures modifies most probably by increasing ryegrass competition at early spring. [ABSTRACT FROM AUTHOR]

Due to the genetic improvement of soybean cultivars more adapted to lowlands and to new drainage technologies, there has been a great insertion of soybean cultivation in rotation with irrigated rice in South America. Soybean has innumerable features beyond the fact that it is a legume, which can directly impact the microbial activity and diversity of the soil and the development of crops established in succession. Therefore, the objective was to evaluate nitrogen (N) dynamics, extracellular enzyme activity, soil microbial community, and the subsequent development of ryegrass in a Gleysol cultivated with irrigated rice and soybean in an area with a long history of irrigated rice cultivation. The experiment was conducted in the crop season 2015/16 at the Rice Research Station, Rio Grande do Sul, Southern Brazil, in an area that had been cultivated for 70 years with irrigated rice. The treatments used are irrigated rice cultivation and soybean in randomized blocks with 4 replicates. Hydrolysis of fluorescein diacetate, acid phosphatase, urease and β-glucosidase were evaluated. Bacterial communities were estimated in soil by extracting DNA and sequencing the V3-V4 region of the 16S rRNA gene. Ryegrass dry biomass was quantified after irrigated rice and soybean. Greater mineral N availability (+ 49%), higher extracellular enzyme activity (+ 51%) and microbial diversity (+ 7%) were observed after soybean cultivation compared to irrigated rice. These changes, after soybean cultivation, had a direct impact on the development of ryegrass plants, which showed higher ryegrass dry biomass production. Thus, the adoption of soybean rotation in areas traditionally cultivated with irrigated rice is an important agronomic strategy to increase the sustainability of agriculture, since it allows the increase of soil quality and availability of nutrients in lowland crop production systems. • Soybean cultivation increased nitrogen availability by 49% and enzyme activity by 51%. • Soil microbial diversity increased by 7% with soybean cultivation. • The development of ryegrass tripled in succession to soybean compared to rice. [ABSTRACT FROM AUTHOR]

The objective in this study was to characterize the productive potential, monthly yield distribution, and forage plantpart and botanical composition of black oats and annual ryegrass under harvest strategies in São Paulo. The experimental design was completely randomized with treatments corresponding to the combination among stand composition (exclusive oats, exclusive annual ryegrass, or oats + ryegrass, O+R) and harvest strategies (at 95% LI or every 30 days of regrowth, FIXED), in a factorial arrangement with three replications. Stands managed by LI accumulated 1580kg DM ha-1 harvest-1, and those managed by FIXED 2020kg DM ha-1 harvest-1. Leaf proportion was higher in ryegrass (70%), followed by O+R (64%) and oat (52%). Swards managed by LI had higher proportion of leaves and less stem than those harvested at FIXED intervals. The proportion of ryegrass was higher under the LI management (64%), than under the FIXED (70%). Over time there was the replacement of oats by ryegrass in the mixed canopy composition. Exclusive ryegrass stands are recommended. Both harvest strategies can be adopted for these winter forages in integrated systems of agriculture and livestock. [ABSTRACT FROM AUTHOR]

This study tested the hypothesis that different sward structures, which were constructed by varying the pre- and post-grazing sward heights of annual ryegrass pasture ( Lolium multiflorum Lam.) in southern Brazil, affect the short-term intake rate ( STIR) by dairy cows. Treatments consisted of four sward-management strategies defined by a combination of two pre- (25 and 15 cm) and two post-grazing sward heights (10 and 5 cm): 15-05, 15-10, 25-05 and 25-10. A completely randomized block design with four replicates was used for the experimental design. The STIR was determined by the double-weighing technique. Jaw movements were evaluated using automatic recorders ( IGER Behaviour Recorder). The results showed that treatment 25-10 allowed the animals to collect more herbage with a greater bite mass and thus resulted in a greater STIR. Treatments in which sward height was reduced to 10 cm generally favoured the ingestion process than treatments with a post-grazing sward height of 5 cm. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the practical application of herbicide, overseeded annual ryegrass for the establishment of forage peanut (Arachis pintoi) in natural vegetation. The experiments was conducted from October 2007 to November 2008, Estação Experimental Terras Baixas (ETB) - Embrapa Clima Temperado, Capão do Leão - RS. The treatments were arranged in a randomized block design in split plots with four replications. The plots were represented by the treatments with and without herbicide (3L ha-1 of commercial herbicide glyfosate). The subplots were defined by the absence of forage peanut, the presence of forage peanut, the presence of forage peanut overseeded with annual ryegrass. The frequencies of species of natural vegetation were not influenced by grazing and overseeded ryegrass. The establishment of forage peanut Arachis pintoi is benefited by the herbicide. However, it is a practice that causes a significant reduction of species of forage interest. The presence of annual ryegrass provides a favorable environment for forage peanut during the cool season. [ABSTRACT FROM AUTHOR]

In order to evaluate the satellite image patterns between such cool season cereals cultivated areas intended for grazing or grain production, Normalized Difference Vegetation Index (NDVI) temporal profiles were analyzed. This data was acquired from twenty nine wheat and annual ryegrass cultivated areas in the states of Rio Grande do Sul and Paraná. For each area, the cultivated species (wheat or ryegrass), as well as the respective central point coordinates, acquired via Global Positioning System (GPS) was informed. NDVI values were extracted over each monitored area from MODIS (Moderate Resolution Imaging Spectroradiometer) sensor images, with spatial resolution of 250 meters. The NDVI temporal profiles showed that grain production areas have a typical agricultural field spectral pattern. The same pattern was not observed for the grazing pasture areas. The differences observed in these temporal patterns are defined by the changes that grazing has imposed on the phenology and morphology of these plants. [ABSTRACT FROM AUTHOR]

The interest was the seed longevity dynamics of annual ryegrass in natural conditions as an important tool to explain its dynamics in no tillage systems used in the South of Brazil. The species is commonly managed for natural re-sowing and, in this way, allows cattle grazing with reduced costs during the winter time. In February of 2003, twenty bags of nylon screen containing sterilised soil with 100 seeds in each were randomly buried in the field, 5 cm deep. Around every three or four months, four sacks were exhumed. Seeds were counted and tested using germination and tetrazolium tests. The seeds showed high primary dormancy, which was overcome very fast. After 108, 226, 326, 565 and 732 days of burial there were no significant differences as the secondary dormancy of the seeds that did not germinate in autumn was not high. The last exhumation period was significantly different from the others due to the strong decay on seed viability. As few seeds remained viable after 732 days, the soil seed bank was classified as transient, being evident that in annual pastures the transitory seed banks have a main role in the regeneration of the species. [ABSTRACT FROM AUTHOR]

• Exchangeable K forms were not sensitive to detect different amounts of K added. • K addition greater than the export resulted in the fixation of K surplus by the soil. • Rotation of rainfed crops with paddy rice increased the fixation of K by the soil. • Non-exchangeable K was more useful to understanding the soil K dynamics. • K fertilization in 2:1 claymineral soils should focus on the reposition of exported K. Diversified farming systems is a challenge in lowland soils around the world. In Southern Brazil, integrated crop-livestock systems (ICLS) have been used for grain crops and livestock production under no-till. However, their impacts on soil K dynamics are still poorly explored. The aim of this study was to quantify the K forms in the soil and the K budget after 66 months of different flooded rice production systems under no-till ICLS in a subtropical paddy field. Four production systems were established in 2013: (i) flooded rice monocropping under conventional tillage (CT) and winter fallow (R-CT); (ii) no-tillage (NT) flooded rice monocropping with ryegrass pasture in winter (R-ICLS); (iii) NT flooded rice and soybean rotation in the summer and ryegrass pasture in winter (RS-ICLS), and (iv) NT flooded rice, soybean, maize and stapf grass rotation in the summer period and ryegrass and clover pasture in the winter (RSM-ICLS). In 2018, soil samples were taken at the 0–10, 10–20 and 20–30 cm soil layers. Exchangeable potassium (K), non-exchangeable K, structural K, and total K were evaluated. Exchangeable K was not affected by the treatments. The higher the difference between inputs and outputs of K in the systems evaluated, the higher was the content of structural and total K in the soil. However, the K budget in the system was not sufficient to fully explain the variation in the non-exchangeable K content in the soil. Comparing the systems with the same frequency of flooded rice cultivation, the difference between inputs and outputs of K was about 2.3 times higher in the R-ICLS system (830 kg ha−1 of K) compared to R-CT (366 kg ha−1), which increase in 70 % the concentration of non-exchangeable K in the 0–30 cm soil layer (622 and 361 mg kg−1 in the R-ICLS and R-CT, respectively). In the systems where flooded rice rotates with rainfed crops (RS-ICLS and RSM-ICLS), the drying cycles resulted in K fixation with higher energy, turning the surplus of K added via fertilization into structural forms. These results indicate that lowland soils cultivated with K fertilization rates greater than the export of K can result in a fixation of K, decreasing its availability in the short-medium term. Moreover, it strongly emphasizes that adequate K fertilization in lowland soils with 2:1 clayminerals should focus on the reposition of exported K in order to prevent temporary fixation of K by fixation on structural forms. [ABSTRACT FROM AUTHOR]

Transgenic glyphosate-resistant soybeans (GRS) have been commercialized and grown extensively in the Western Hemisphere, including Brazil. Worldwide, several studies have shown that previous and potential effects of glyphosate on contamination of soil, water, and air are minimal, compared to those caused by the herbicides that they replace when GRS are adopted. In the USA and Argentina, the advent of glyphosate-resistant soybeans resulted in a significant shift to reduced- and no-tillage practices, thereby significantly reducing environmental degradation by agriculture. Similar shifts in tillage practiced with GRS might be expected in Brazil. Transgenes encoding glyphosate resistance in soybeans are highly unlikely to be a risk to wild plant species in Brazil. Soybean is almost completely self-pollinated and is a non-native species in Brazil, without wild relatives, making introgression of transgenes from GRS virtually impossible. Probably the highest agricultural risk in adopting GRS in Brazil is related to weed resistance. Weed species in GRS fields have shifted in Brazil to those that can more successfully withstand glyphosate or to those that avoid the time of its application. These include Chamaesyce hirta (erva-de-Santa-Luzia), Commelina benghalensis (trapoeraba), Spermacoce latifolia (erva-quente), Richardia brasiliensis (poaia-branca), and Ipomoea spp. (corda-de-viola). Four weed species, Conyza bonariensis, Conyza Canadensis (buva), Lolium multiflorum (azevem), and Euphorbia heterophylla (amendoim bravo), have evolved resistance to glyphosate in GRS in Brazil and have great potential to become problems. [ABSTRACT FROM AUTHOR]

• Trichoderma stimulates resistance against to Pyricularia oryzae in Lolium multiflorum. • Coated seeds of L. multiflorum with T. atroviride reduces the severity of P. oryzae. • Silicon is accumulated in the leaves and improves the resistance to blast. • Biochemical and physical defenses are related to the protective action against blast. Ryegrass (Lolium multiflorum L.) is a forage species with a high content of protein and good palatability and digestibility. In winter, it is frequently used in southern Brazil as feed for livestock. The high humidity in this region is propitious for gray leaf spot, a disease caused by Pyricularia oryzae , considered to be the region's main biotic problem. In this study, we aimed to evaluate the effect of three types of management, namely seed coating with Trichoderma atroviride (T), application of silicon in the soil (Si), and combination of both treatments (TSi), to reduce the severity of gray leaf spot. In the first phase, the capacity of 10 native isolates of Trichoderma spp. were evaluated in vitro for direct inhibition of P. oryzae based on tests of dual cultures (DC), antibiosis for volatile (Vol), and non-volatile compounds (Nvol). In vivo trials involved the ability to induce resistance responses, such as quantifying severity (SEV) and number of lesions (NL) per cm2 of leaf area. In the second phase, the efficacy of T, Si, and TSi was tested under greenhouse conditions. The lesion expansion rate (LER), relative efficiency of infection (RIE), SEV and NL were measured (after inoculation with P. oryzae), and in parallel the activities of the enzymes superoxide dismutase (SOD), catalase (CAT), peroxidase (POX) and phenylalanine ammonia-lyase (PAL) were quantified (at 24, 48, 72, and 96 h). The strain TR10 (identified by polyphasic taxonomy as T. atroviride) showed one of the highest inhibition values in Vol (23%) and DC (35%). Plants from seeds treated with the strain TR10 had the lowest levels of SEV (5.5%) and NL (3), in contrast with the other strains according to analysis of variance. Under greenhouse conditions, significant differences (P < 0.0001) were found for LER, RIE, NL and SEV in T, Si, and TSi concerning TE (control treatment). The defense response of T was related to the activities of CAT, POX, and PAL (mainly), while for Si, other mechanisms, which were not evaluated in this study, might have contributed to disease reduction, and TSi did not show an additive effect. The treatment of seeds with T. atroviride and the application of Si in the soil improved the resistance of L. multiforum against infection by P. oryzae. [ABSTRACT FROM AUTHOR]

Ryegrass (Lolium multiflorum Lam.) is the main winter weed of crops in Southern Brazil. High competitiveness, adaptability, widespread resistance to herbicides and seed dormancy make the plant a permanent problem. Herbicides, as well as plant growth regulators, can be used as a management option for ryegrass seed production, however there is no consensus among authors at which stage of the plant the application is most effective. Thus, this study aimed to evaluate the production and physiological quality of ryegrass seeds in response to the application of herbicides and plant growth regulators in three stages of plant development (inflorescence emergence, flowering and fruit development). Each treatment consisted of applying two different doses of each of the active ingredients: ammonium glufosinate, clethodim, glyphosate, iodosulfuron-methyl, paraquat and 2,4-D (herbicides); ethephon and trinexapac-ethyl (plant growth regulators), still an untreated control, totaling 17 treatments for each stage of development. The experimental design used was randomized blocks, with three replications. The variables evaluated were: seed production (kg ha−1), thousand seed weight (g), viability (%), germination (%), first germination count (%), dormant seeds (%) and dead seeds (%). The ryegrass seed production reduced 100% with clethodim, glyphosate, ammonium glufosinate or paraquat applied in the inflorescence emergence or flowering stages. In the fruit development stage, all treatments (herbicides and plant growth regulators) caused deleterious effects on seed production, the greatest effect occurred with paraquat (95%). Paraquat, ammonium glufosinate and clethodim affected the physiological quality of the seeds when applied in fruit development stage. This research demonstrated that the application of herbicides in the ryegrass reproductive stage decreases its seedbank replenishment (natural re-sowing), with the potential to harm its progeny. [ABSTRACT FROM AUTHOR]