Paspalum Dilatatum Research Articles

How Long Should Grasses of South American Campos Grasslands Rest for Stockpiling Forage?

Stockpiling forage (i.e., deferring grazing) is one way to provide forage for livestock during intervals of low pasture growth, but there are trade-offs as nutrient content declines with increasing forage maturity. Phosphorous (P) concentration, crude protein (CP) content and organic matter digestibility (OMD) were evaluated in two C3 and four C4 grasses native to the South American Campos grasslands. These were: Bromus auleticus (BROAUL) and Nasella neessiana (NASNEE) as C3 grasses and Andropogon lateralis (ANDLAT), Mnesithea selloana (MNESEL), Paspalum dilatatum (PASDIL), and Paspalum notatum (PASNOT) as C4 grasses. The grasses were grown in pots during five stockpiling periods (450, 900, 1350, 1800 and 2250 degree days, approximately 20, 40, 60, 80 and 100 days). As the forage deferment increased, the nutritional value decreased more in C4 than in C3 grasses. Short rest periods (approximately 40 days) are recommended for PASDIL and MNESEL, and medium rest periods (approximately 80 days) for ANDLAT and PASNOT. However, the C3 grasses BROAU and NASNEE maintained high P and CP concentrations and may be the most appropriate option for long rest periods (≥100 days). This information is important to manage different Campos grassland communities for the optimal rest period according to the dominant species.

Microplastics promote the invasiveness of invasive alien species under fluctuating water regime

Abstract Microplastic (MP) pollution and alien plant invasions are two important threats to terrestrial ecosystems. Microplastics alter the physical and chemical characteristics of soil, potentially affecting the performance of alien plants. However, previous studies have overlooked the impact of weather on invasive plants in areas polluted by MPs. With the global increase in extreme rainfall events, it is imperative to redefine the correlation between MPs and invasive plants. Here, we conducted an experiment in a climate chamber to examine the effects of MPs on the growth and development of both native and invasive alien plants under constant and fluctuating water regime (FWR). The FWR simulated extreme water pulses during the 2016–2020 growing seasons in Wuhan, China. Our results indicated that biomass accumulation and root development were influenced by water conditions and MP pollution in both invasive and native species. The extent of the effects varied between the two groups of plant species. FWR promoted plant growth and fine root development in invasive plants but reduced the maximum quantum efficiency of photosystem II (Fv/Fm) and nonphotochemical quenching (NPQ) indices of native plants. Moreover, FWR attenuated the negative effects of polybutylene succinate (PBS, degradable MPs) on biomass and root characteristics (length, surface area and tips). FWR compensated the negative impacts of MPs on the total and below‐ground biomass of the invasive species Paspalum dilatatum and Sphagneticola trilobata, but not on the native species. Consequently, invasive species showed better performance than native species in the fine root development of biomass growth and chlorophyll fluorescence under the combined effects of MPs and FWR. Synthesis and applications. Our findings suggest that MP pollution enhances the competitiveness of invasive alien species over the native species when exposed to pronounced dry–wet water cycle conditions, potentially affecting the composition and biodiversity of the ecosystems. Thus, controlling MP pollution should be a part of the management strategy to conserve biodiversity and ecosystems.

Insect diversity and abundance in three forest areas of Lagos State

Mangrove forest ecosystem preserves diversity of species, which includes insects. Insects serve as bioindicators, pollinators and nutrient recyclers in the forest. However, the number of insects decline as the forest fades. We conducted this field survey to assess the diversity and abundance of insect species in three selected mangrove swamp forests located in Lagos State, Nigeria. Samples were collected fortnightly using different techniques, for a period of three months. Insects collected were preserved in 70% alcohol, but butterflies and moths were preserved dry. Representative samples were identified with picture insect mobile application V1.0.8 and confirmed using standard identification keys. Vegetation cover was quite similar in all the areas sampled comprising of Alchornea cordifolia, Eragrosis racemose, Paspalum dilatatum and Avicennia germania. A total of 182 insects were collected belonging to seven Orders, 18 Families and 38 species. The most dominant Order was Coleoptera with relative abundance of 66.48% and the least was Hemiptera (0.59%). The Order Odonata was the most diverse (HꞋ=1.09), and the most dominant species were Pantala flavescens and Sympetrum fonscolombii, having relative abundance of 8.24% each, followed by Palpopleura lucia (7.69%), Ceriagrion glabrum (7.14%) and Lestinogomphus africanus (6.04%). Psedagrion kersteni was rare with relative abundance < 0.5%. Iba site had the highest species diversity (HꞋ=1.24) but lowest number of individuals. This study documents the diversity and abundance of insects in the fast-disappearing mangrove forest of Lagos State, Nigeria.

Diversity of the Ground Cover Crop Nephrolepis Biserrata in Oil Palm Plantations on Various Soil Types

Ground cover crops play an important role in maintaining the ecological balance in oil palm plantations. Nephrolepis biserrata, as a cover crop species, has not been extensively studied, especially in relation to soil type and vegetation level. This study aimed to analyze the distribution and dominance of Nephrolepis biserrata in oil palm plantations on various soil and vegetation levels. This quantitative research was conducted in oil palm plantations in Central Kalimantan Province using a survey method with purposive sampling. Nine treatment combinations of three soil types (Histosols, Ultisols, and Spodosols) and three vegetation levels (low, medium, and high) were tested on 81 test plots. Data analysis includes diversity index (Ĥ), uniformity index (E), dominance index (C), importance value index (INP), and relative dominance (DR). The results of the research show that N. biserrata has good adaptability and dominance as a ground cover crop in the producing crop (TM) phase in oil palm plantations, especially on Spodosol-type soils. Nephrolepis exaltata and Nephrolepis biserrata showed the highest INP in Ultisols (76.65%; 7.64%), Spodosols (48.03%; 82.75%), and Histosols (61.34%; 23.98%). There are no cover crop species that dominate exclusively in all soil types (0.078-0.185). Ultisols have high cover crop diversity (3,107), whereas Spodosols (2,130) and Histosols (2,595) have medium diversity. Ageratum conyzoides (15.08%) and Paspalum dilatatum (10.06%) also had significant INP in all soil types. Different soil conditions influence the number of cover crop vegetation species and communities in oil palm plantations.

Nonessential amino acids in tropical ruminant feed: Investigating grass and legume forages of Indonesia.

This study aimed to examine the concentration of nonessential amino acids (NEAAs) in ruminant feed in tropical areas, with a focus on forage grasses and legumes in Indonesia. A total of 11 grasses (Chrysopogon zizanioides, Brachiaria brizantha, Brachiaria humidicola, Paspalum dilatatum, Paspalum atatum, Chloris gayana, Pennisetum polystachion, Panicum maximum, Cenchrus biflorus, Andropogon canaliculatus, and Digotaria decumbens) and six legumes (Arachis hypogaea, Pueararia Javanica, Centrosema pubescens, Clitoria ternatea, and Arachis pintoi) were analyzed for NEAA content using high-performance liquid chromatography (HPLC). Based on the results of this research, it was found that almost all NEAA content in forage was less than 3% (Serine (Ser), Alanine (Ala), Glycine (Gly), Tyrosine (Tyr), Proline (Pro), Cysteine (Cys), and Asparagine (Asn), except for glutamic (Glu) acid and arginine (Arg) in some legumes. The Glu content in grass ranges from 0.76% to 2.61%, and the Arg content ranges from 0.92% to 2.09%. These two NEAAs were most abundant in grasses and legumes, with concentrations of 5.10% to 6.27% and 3.10% to 5.53%, respectively. Our study concluded that Glu and Arg were the most abundant NEAAs in tropical forages in Indonesia, with legumes having a higher concentration of NEAAs compared to grasses. Among the legumes, A. hypogaea had the highest NEAA content (23.40%), while among the forages, C. zizanioides had the highest NEAA content (12.37%). However, it was observed that neither legumes nor grasses could fulfill the metabolizable TNEAAs requirements for gaining cattle (250 kg of empty body weight gain), unlike commercial concentrates, which were found to meet the requirements, especially for Arg, Glu, and thyronine. The provision of concentrate is necessary to supplement forage to meet the NEAA needs for cattle.

PSIII-23 Supplementing Bovacillus to Newly Weaned Cattle During a 90-Day Grazing Period

Abstract This experiment compared performance, health, and physiological responses of weaned cattle receiving Bacillus subtilis derivative in a 90-d grazing period. Recently weaned Angus-influenced steers (n = 120) were obtained from an auction yard on d -1 and transported 150 km to research facility. Immediately after arrival on d -1, shrunk body weight (BW) was recorded and steers were grouped with access to native forage and water. On d 0, an additional body weight was recorded and combined with d -1 values to represent initial body weight (BW; 236 ± 2 kg). Steers were ranked according to initial 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 with either: 1) Bacillus subtilis ingredient (BOV; 2 g/steer daily of Bovacillus; Chr Hansen A/S, Horsholm, Denmark), or 2) no additive (CON). Cattle received treatments for the duration of the experiment (d 0 to d 90) while housed in pastures containing stockpiled native forage, primarily Cynodon dactylon and Paspalum dilatatum, as well as free-choice access to water and a commercial mineral + vitamin mix not including ionophores. Bovine respiratory disease (BRD) signs were assessed daily throughout the experimental period. Steer unshrunk BW was recorded on d 14, 28, 56, and 90 and shrunk BW recorded on d 91 added 8% shrink as final BW. Blood samples and fecal swabs were collected from all steers on d 0, 14, 28, 56, and 90. Average daily gain (ADG) was increased in BOV groups compared with CON (0.858 and 0.760 kg/d, respectively) from d 56 to d 90 (P = 0.09) although this BW gain was not sufficient to impact final BW. Steer BW did not differ between treatments for all days (P ≥ 0.43). Incidence of BRD was within the expected range for high-risk stocker cattle, although the number of sick animals was not reduced due to BOV supplementation (P = 1.00). Steers not completing the trial due to health-related complications tended to be increased in CON vs. BOV (P = 0.08). Differences in percentage of steers not completing the experiment, in conjunction with treatment effects for ADG in the final third of the experiment, increased the production total BW per BOV pasture by 43% (790 vs. 550 kg BW change; P = 0.02). Bacillus subtilis supplementation was effective in increasing production BWt during a 90-d grazing period despite no observed difference in BRD incidence.

Weed Population Dynamics under Organic, Bio-dynamic, Conventional Bt and Non-Bt Cotton (Gossypium hirsutum)

Aim: In order to compare the weed seed bank and population dynamics under organic, biodynamic, Bt-conventional, and non-Bt conventional management systems of cotton (Gossypium hirsutum), a field experiment was carried out.
 Study Design: Randomized Block Design (RBD)
 Place and Duration of Study: bioRe-FiBL research trails, bioRe Association, Kasrawad, Khurgone, Madhya Pradesh during the kharif season of 2020-21.
 Methodology: Five distinct crop management techniques were used in the field experiment, each duplicated four times, and the experiment was set up using a randomized block design. The treatments were distributed at random to different plots. The five management treatments were Absolute Control (no fertilizers), Conventional management of non-Bt cotton, Conventional management of Bt cotton, Bio-dynamic and Organic management of cotton. For the duration of the experiment, four 1 m × 1 m (1 m2) quadrats were randomly placed on each experimental plot's four sides, and different biometric observations were recorded from each quadrant according to its treatment. For the purpose of collecting the necessary observations, two of these quadrants were regularly weeded every 20 days, while the other two were left unweeded for the duration of the experiment.
 Results: The dominant weed species includes Panicum dichotomiflorum, Cyperus rotundus, Paspalum dilatatum, Euphorbia hirta, Acalypha indica and Digeria arvensis. Poaceae was the dominant family in terms of composition. There was very less variation in the weed flora between the treatments. Significantly higher weed seed bank, weed species, weed density and weed dry weight were observed in Organic and Biodynamic cotton than in the Conventional cotton. Weed control efficiency was found to be maximum in the Conventional cotton compared to the Organic and Biodynamic cotton.
 Conclusion: From the experiment, it can be concluded that the Conventional cotton especially Conventional management Bt Cotton was found to be most efficient among all the treatments. However, the Organic cotton was observed with high number of overall plant species and best in conserving the plant species biodiversity.

Effects of endophytes Trichoderma amazonicum and Acremonium strictum on fungal pathogens of Paspalum

AbstractIn natural ecosystems, many plants engage in symbiotic interactions with fungal endophytes which can have impacts on host plant communities. In South American grasslands, several endophytes have been isolated from different Paspalum species. The aim of this work was to evaluate the antagonistic effect of endophytes Trichoderma amazonicum and Acremonium strictum against Claviceps paspali through in vitro and in vivo assays. In addition, they were evaluated as biocontrol agents against fungal pathogens which produce leaf spots such as Alternaria alternata and Bipolaris sp. through in vitro experiments. The in vitro assessment was conducted by dual culture between the antagonists and the three pathogens. For the in vivo assay, plants of Paspalum notatum and Paspalum dilatatum were planted in the field in a completely randomized block design with six replications. Three treatments were applied: T1 = endophyte inoculum, T2 = fungicide, and T3 = control. Seed yield, seed set, healthy seed set, and weight of healthy seed set per kilogram of seeds were evaluated for three timepoints. Trichoderma amazonicum exhibited a high growth inhibition, while A. strictum a moderate to low effect in vitro. In the in vivo assay, significant differences were observed among treatments in both species. T1 increased the kilogram of healthy seed set per 100 kg of seed by increasing the seed set and weight of healthy seed set in at least one of the evaluated dates in P. notatum and P. dilatatum. Based on these results, T. amazonicum and A. strictum have antagonistic effects on the pathogens assessed.

Seedling emergence of tropical perennial pasture species in response to temperature used to determine sowing time recommendations

Tropical pasture grasses and legumes can be highly productive and persistent and fill the summer-autumn feed gap typical of temperate pasture systems in southern Australia. However, more information is needed on optimum temperature range for seedling emergence because this will influence sowing time recommendations. A replicated field experiment was conducted at 5 locations in New South Wales over a 12-month period to determine the optimum temperature for emergence of a range of tropical species: Rhodes grass (Chloris gayana Kunth), Makarikari grass (Panicum coloratum L. var. makarikariense Gooss.), kikuyu grass (Cenchrus clandestinus (Hochst. ex Chiov.) Morrone), digit grass (Digitaria eriantha Steud.), panic grass (Megathyrsus maximus (Jacq.) B.K. Simon & S.W.L. Jacobs), paspalum (Paspalum dilatatum Poir.), Urochloa hybrid (Urochloa decumbens × U. ruziziensis × U. brizantha), 2 cultivars of Desmanthus virgatus (L.) Willd. (cultivars ‘Marc’ and ‘JCU2’), D. bicornutus (S. Watson), D. leptophyllus (Kunth) and D. pernambucanus (L.) Thell.). Rhodes grass emerged satisfactorily over the longest time across all sites, exhibiting the greatest temperature range over which emergence occurred, while Makarikari grass and panic grass had the narrowest temperature range for emergence. The temperature for 50% emergence differed between the tropical species and whether the soils were warming or cooling. Rhodes grass had the lowest 50% emergence temperature (17 °C) while paspalum had the highest (22 °C). Results showed that temperature for 50% emergence is a useful indicator for determining sowing time in warming soils.

Germination, overcoming seed dormancy and endozoochory dispersal by cattle of native species from natural grassland

AbstractNatural grasslands, one of the main ecosystems worldwide, are under threat and native species are desired when addressing restoration issues. The main processes for grasslands restoration success are plant establishment and seed addition in the soil. Thus, it requires overcoming barriers that prevent germination and seed dispersal strategies. This study aimed to assess the germination potential, treatments to overcome seed dormancy and endozoochory dispersal of forage native species by cattle. Seeds from 21 native species from the four most common botanical families (Poaceae, Asteraceae, Fabaceae and Cyperaceae) were collected in a natural grassland area (Pampa Biome) and used in the experiments. Experiment I: germination under controlled conditions of all species was carried out and compared to commercial forage (Paspalum notatum cv. “Pensacola”). Experiment II: three treatments to overcome seed dormancy (mechanical and chemical scarification; priming agent) were tested in six species. Experiment III: the recovery, viability and germination of native P. notatum Flüggé and Desmodium incanum DC seeds from cattle faeces were evaluated. The results show that Paspalum umbrosum Trin. and Saccharum angustifolium Nees have high germination potential when compared to commercial forage. The treatments to overcome seed dormancy increased the germination of D. incanum, Paspalum plicatulum Michx. and Paspalum dilatatum Poir. Total seed recovery of 15% (P. notatum) and 26% (D. incanum), without affecting seed viability, show that cattle are able to supply the soil seed bank with native species. Germination potential, treatments to overcome seed dormancy and endozoochory dispersal of forage native species may be exploited in natural grassland restoration.

Effect of irrigation on biomass production and components of dallis grass (Paspalum dilatatum) and Bahia grass (P. notatum) in Uruguay

Use of irrigation in forage production systems based on perennial C4 grasses has been limited because of inconsistent responses of biomass production to water. The effects of three different levels of irrigation on growth of Paspalum notatum (Bahia grass) and P. dilatatum (dallis grass) over two consecutive growing seasons were studied. The phenological state of the plants was inferred by the proportion of lamina and non-lamina components. While irrigation failed to increase annual dry matter yield of forage, phenological composition of forage was affected by irrigation with both species showing changes in distribution of dry matter accumulation among different above-ground plant parts. Future research on these species should study the effects of moisture deficit on phenology to better understand the effects of irrigation.

Numerous distributional novelties collected by students for Idaho, Kansas, Missouri, Oklahoma, and Texas, U.S.A.

Thirteen distributional records from Idaho, Kansas, Missouri, Oklahoma, and Texas are reported for seven native and five non-native plant species, many based on course-related collections by students. These include state records for three taxa: Cyperus brevifolioides and Paspalum dilatatum for Kansas, and Sphaeralcea parvifolia for Idaho. We also report ten county records, including significant range extensions for Dinebra panicoides. We also report what we believe to be pseudovivipary in Setaria pumila.

Glyphosate sprayed on the pre-existing vegetation reduces seedling emergence and growth of forage species

Seeding pastures or forage crops by no-tillage methods usually involves the spray of glyphosate to suppress the existing vegetation. While many studies found detrimentaleffects of glyphosate on seed germination and seedling growth of the subsequent crop, others found negligible effects. This study aimed to evaluate the effect of glyphosate spraying on germination, seedling emergence and seedling growth of four forage species: Trifolium repens, Lotus tenuis, Festuca arundinacea and Paspalum dilatatum. The experiment was carried out spraying glyphosate on the pre-existing vegetation and on bare soil 1, 30, 60 and 90 days before sowing, and a control treatmentsprayed with water. Glyphosate sprayed on pre-existing vegetation 1 to 60 days before seeding reduced emergence, while sprayed 1 to 30 or 1 to 60 days before seeding reduced seedlings belowground biomass and root length of all species and aboveground biomass of legumes respect to sprayed 90 days before seeding, sprayed on bare soil, and control treatment. This herbicide would remain active in the soil environment for at least 60 days after spraying when it was previously absorbed by plants, causing a severe damage to seedlings emergence and growth. Highlights: Glyphosate sprayed on pre-existing vegetation 1 to 60 days before seeding reduced seedling emergence of Trifolium repens, Lotus tenuis, Festuca arundinacea and Paspalum dilatatum. Glyphosate sprayed on pre-existing vegetation 1-30 or 1-60 days before seeding reduced seedlings belowground biomass and root length of all species and aboveground biomass of legumes Gyphosate sprayed 90 days before seeding or sprayed on bare soil did not affect seggling emergence and growth. Gyphosate would remain active in the soil environment for at least 60 days after spraying when it was previously absorbed by plants.

Efectos alelopáticos de plantas de Cynodon dactylon L. en praderas naturales invadidas

We evaluated the allelopathic effect of the invasive species Cynodon dactylon from a natural grassland and overseeding grassland intersowing with legumes and fertilization with phosphorus, on two native grasses, Paspalum notatum and Paspalum dilatatum. Due to what was observed in fertilized grasslands, where the cover of C. dactylon increases, P. notatum decreases and P. dilatatum is not affected, it was expected that the allelochemicals from the intersowing and fertilized grasslands would have a negative effect on P. notatum. The effect of aqueous extracts of C. dactylon on the germination, growth and development of the two grasses studied. Contrary to our expectations, we could not detect inhibitory effects of the treatments on germination and adult plants in autumn, but an increment of germination of both species irrigated with extracts from intersowing and fertilized grasslands. In contrast, in spring, the responses were neutral. The results obtained do not indicate that aqueous extracts from fresh leaves have an allelopathic effect that explains the invasive success of C. dactylon and the decrease of P. notatum in fertilized grasslands, although other approaches should be considered for its study.

Monitoring fall CO2 efflux of dallisgrass and hybrid bermudagrass: Implications for nonselective weed control

AbstractChemical control options for dallisgrass (Paspalum dilatatum Poir.) are limited, inconsistent, and damaging to desirable species. Dallisgrass and hybrid bermudagrass [Cynodon dactylon (L.) Pers. × Cynodon transvaalensis Burtt Davy] may enter dormancy at different times, allowing for safe, efficacious use of nonselective herbicides for dallisgrass control. Field experiments evaluated dallisgrass and hybrid bermudagrass dormancy by measuring plant respiration in fall and subjecting the carbon efflux data to a nonlinear exponential decay regression model fitted against cooling degree‐days (CDDs). Total plant respiration differed between the species at trial initiation. Dallisgrass exhibited higher net respiration, indicating that each species proceeded into dormancy at different rates. A postemergence dallisgrass control trial was initiated at 5 to 125 CDD22C to evaluate potential rates of quinclorac (1.5, 2.3, and 3.0 kg acid equivalent ha–1), monosodium methanearsonate (6.1, 9.1, and 12.1 kg a.i. ha–1), glyphosate (5, 7.6, and 10.1 kg a.i. ha–1), and thiencarbazone + foramsulfuron + halosulfuron (0.14, 0.18, and 0.22 .kg a.i. ha–1). Dallisgrass control 36 wk after the initial treatment was greatest with glyphosate (≥97%). Minimal bermudagrass survival was observed next spring in response to fall glyphosate. Total plant respiration per sample area differed between species at trial initiation. However, dallisgrass exhibited greater net respiration, indicating differences in behavior concerning the initiation and procession of dormancy between dallisgrass and bermudagrass. Microclimates such as shaded or low‐lying areas may yield different results. Further research should determine the significance of this phenomenon to use nonselective herbicides to control dallisgrass in bermudagrass.

Estimation of forage quality by near infrared reflectance spectroscopy in dallisgrass, Paspalum dilatatum, poir

Dallisgrass ( Paspalum dilatatum Poir.) is an economically important and widely cultivated forage crop for livestock feeding in the tropical, subtropical, and warm temperate regions because of good adaptation to unsuitable pasture conditions. In this study, 216 dallisgrass samples were used to develop near infrared reflectance calibrations to estimate five forage quality parameters: dry matter (DM), crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF) and ash. Second derivative pretreatment was applied for calibration of DM, CP and NDF while a first derivative pretreatment was used for ADF and ash. The coefficients of determination in the internal validation set (r 2) were 0.78 for DM, 0.80 for CP, 0.95 for NDF 0.75 for ADF, and 0.71 for ash. The relative predictive determinant ratios for calibration indicate that the NDF equations were acceptable for quantitative prediction of dallisgrass quality, whereas the DM, CP, ADF, and ash equations were useful for screening purposes. The near infrared prediction models developed in this study can be used for screening in the forage breeding researches to be carried out for five quality parameters in the future.

New Entities ofPaspalumand a Synopsis of the Dilatata Group

Abstract—New entities in the allopolyploid Dilatata complex ofPaspalumare formally described and illustrated. Three sexual tetraploids formerly subsumed underPaspalum dilatatumare recognized as discrete taxonomic entities:P. plurinerveandP. vacarianumare described as new species, andP. dilatatumsubsp.flavescensis upgraded to species rank asP. flavescens.BothP. vacarianumandP. plurinerveare distributed in the Brazilian southern Plateau (Planalto Meridional), in the states of Rio Grande do Sul and Santa Catarina, the first one in the eastern region and the second one in the western region including adjacent areas of NE Argentina.Paspalum flavescensis distributed in southeastern Uruguay and the provinces of Buenos Aires and Córdoba (Argentina). The apomictic allohexaploidP. torrense, distributed along the coastal areas of the Brazilian states of Rio Grande do Sul, Santa Catarina, and Paraná, and adjacent regions along the edge of the southern Plateau, also deserves specific status, whereas two further hexaploid biotypes are differentiated from the pentaploidP. dilatatumvar.dilatatumand described asPaspalum dilatatumvar.chiruandP. dilatatumvar.uruguaianense.Paspalum dilatatumvar.chiruis restricted to a small area around the locality of Molles Grande, in the department of Paysandú, Uruguay; whereasP. dilatatumvar.uruguaianenseis distributed in the SW of Rio Grande do Sul, Brazil, and northern Uruguay. The Dilatata group ofPaspalumis thus comprised of 8 species and 3 varieties, which are summarized here and for which an identification key is provided.

Development of Protocols for Regeneration and Transformation of Apomitic and Sexual Forms of Dallisgrass (Paspalum dilatatum Poir.).

Paspalum dilatatum (common name dallisgrass), a productive C4 grass native to South America, is an important pasture grass found throughout the temperate warm regions of the world. It is characterized by its tolerance to frost and water stress and a higher forage quality than other C4 forage grasses. P. dilatatum includes tetraploid (2n = 40), sexual, and pentaploid (2n = 50) apomictic forms, but is predominantly cultivated in an apomictic monoculture, which implies a high risk that biotic and abiotic stresses could seriously affect the grass productivity. The obtention of reproducible and efficient protocols of regeneration and transformation are valuable tools to obtain genetic modified grasses with improved agronomics traits. In this review, we present the current regeneration and transformation methods of both apomictic and sexual cultivars of P. dilatatum, discuss their strengths and limitations, and focus on the perspectives of genetic modification for producing new generation of forages. The advances in this area of research lead us to consider Paspalum dilatatum as a model species for the molecular improvement of C4 perennial forage species.

Impact of Verticutting on the Efficacy and Soil Activity of ALS-inhibiting Herbicides for Dallisgrass Control

Dallisgrass (Paspalum dilatatum Poir.) control with postemergence herbicides is inefficient and inconsistent from year to year. Control with acetolactate synthase (ALS)-inhibiting herbicides may be enhanced through root absorption, but herbicide movement through dense turfgrass canopies may be difficult. The objectives of this research were to evaluate the influence of verticutting on the postemergence control of dallisgrass and the presence of ALS-inhibiting herbicides within the soil profile. Long-term dallisgrass control [17 weeks after initial treatment (WAIT)] was enhanced in response to verticutting at one of two locations. This may be attributed to differences in turfgrass management (mowing height) before trial initiation that impacted dallisgrass carbohydrate content and herbicide absorption. However, dallisgrass control with certain herbicides was enhanced at the second location in response to verticutting at earlier rating dates. Thiencarbazone + foramsulfuron + halosulfuron (TFH) and trifloxysulfuron at 112 g·ha−1 a.i. and carrier volume of 1628 L·ha−1 (TRI High CV) following mowing + verticutting resulted in the greatest long-term control 17 WAIT at one of two trial locations, 86% and 85%, respectively. Greenhouse experiments confirmed that mowing + verticutting dallisgrass before treatment followed by irrigation led to an increase in herbicide presence within the soil profile, regardless of herbicide. Presence of TFH went from 6.4 to 8.2 mm, trifloxysulfuron at 28 g·ha−1 a.i. and carrier volume of 407 L·ha−1 went from 6.7 to 8.5 mm, and TRI High CV went from 8.6 to 11.8 mm.

A quantitative revision of the waterlogging tolerance of perennial forage grasses

Waterlogging tolerance of eight C4 and seven C3 perennial forage grasses was reviewed. The median waterlogging duration was similar between species’ type, ranging between 18 and 21 days. Inter- and intra-species variability was found in shoot and root biomass in response to waterlogging. Urochloa brizantha (C4), Brachiaria hybrid (C4) and Dactylis glomerata (C3) were the less tolerant species to waterlogging (shoot biomass median of 45%, 53% and 80% of controls), while U. humidicola (C4), Paspalum dilatatum (C4), Festuca arundinacea (C3) and Lolium perenne (C3) were the most tolerant (shoot biomass median of 97%, 101%, 87% and 94% of controls). A similar ranking of responses was found among species for root biomass. The formation of aerenchyma/root porosity (a key trait for waterlogging tolerance) was evaluated mainly in U. humidicola and P. dilatatum (C4 waterlogging-tolerant species), which showed considerable constitutive porosity (13% and 32%) and final values of 30% and 41% under waterlogging. Net photosynthesis and stomatal conductance as typical leaf physiological responses matched species’ waterlogging tolerance, with the impact of hypoxia higher in C3 than in C4 species. Gaps in knowledge about waterlogging tolerance in forage grasses are: (i) additional studies on C3 perennial grasses for temperate pasture areas prone to waterlogging, (ii) identification of traits and responses aiding plant recovery after waterlogging (and also during the stress), (iii) reassessment of waterlogging tolerance considering plant developmental stage (e.g. adult vs young plants), and (iv) evaluation of sequential (i.e. waterlogging − drought) and combined (i.e. waterlogging + salinity) stresses, which often co-occur in pasture lands.