Wild Radish Research Articles

2,4-D and dicamba removal from the surface of plastic mulch using overhead irrigation: analytical analysis and cucurbit bioassay crop response

AbstractGlyphosate and paraquat are effective preplant burndown herbicide options for multicrop vegetable production that uses plastic mulch, but problematic weeds such as wild radish, cutleaf evening primrose, annual morningglory, or horseweed may not be adequately controlled with these herbicides alone. The herbicides 2,4-D and dicamba could help control these troublesome weeds prior to planting if they can be removed from plastic mulch and thus avoid crop damage. Treatments included 2,4-D (1,065 and 2,130 g ae ha−1) and dicamba (560 and 1,120 g ae ha−1) applied broadcast over plastic mulch a day before transplanting. Just before transplanting, treatments received either 0.76 cm of water via overhead irrigation or no irrigation. Plastic mulch samples were collected at application and planting to determine herbicide presence using analytical techniques, and cantaloupe and zucchini squash were subsequently transplanted on the plastic beds. Analytical ultra-high performance liquid chromatography revealed that 88% to 99% of the initial herbicide concentration was present at crop planting when irrigation was not implemented. At most, a 1/50 rate of dicamba and a 1/500 rate of 2,4-D was present at planting when overhead irrigation was applied prior to transplanting. Maximum cantaloupe and squash injury from 2,4-D with irrigation was 10% and did not influence plant growth, biomass, or yield. For dicamba with overhead irrigation, cantaloupe injury was 35%, vine lengths were reduced by 24%, and maturity was delayed, whereas squash injury ranged from 9% to 12%, with no influence on growth or yield. Without irrigation to wash herbicides from the mulch prior to planting, 60% to 100% injury of both crops occurred with both herbicides. Zucchini squash was more tolerant to dicamba than cantaloupe. Results demonstrated that 2,4-D can be adequately removed from the surface of plastic mulch with irrigation, whereas a single irrigation event was not sufficient to remove dicamba.

Comparative Transcriptome Identifies Gene Expression Networks Regulating Developmental Pollen Abortion in Ogura Cytoplasmic Male Sterility in Chinese Cabbage (Brassica rapa ssp. pekinensis)

Ogura cytoplasmic male sterility (Ogura CMS), originally identified in wild radish (Raphanus sativus), has enabled complete pollen sterility in Brassica plants, but the underlying mechanism in Ogura CMS Chinese cabbage (Brassica rapa ssp. pekinensis) remains unclear. In this study cytological analysis showed that during microsporogenesis the meiosis occurred normally, and the uninucleated pollens subsequently formed, but the development of both binucleated and trinucleated pollens was obviously disrupted due to defects of pollen mitosis in the Ogura CMS line (Tyms) compared with the corresponding maintainer line (231–330). In transcriptome profiling a total of 8052 differentially expressed genes (DEGs) were identified, among which 3890 were up-regulated and 4162 were down-regulated at the pollen abortion stages in an Ogura CMS line. KOG cluster analysis demonstrated that a large number of DEGs were related to the cytoskeleton’s dynamics, which may account for the failure of pollen mitosis during development in the Ogura CMS line. The pivotal genes related to the phenylpropane synthesis pathway (PAL, 4CL and CAD) were significantly down-regulated, which probably affected the formation and disposition of anther lignin and sporopollenin, and eventually led to abnormality in the pollen exine structure. In addition, several key up-regulated genes (GPX7, G6PD and PGD1) related to the glutathione oxidation-reduction (REDOX) reaction indicated that the accumulation of peroxides in Ogura CMS lines during this period affected the pollen development. Taken together, this cytological and molecular evidence is expected to advance our understanding of pollen abortion induced by Ogura cytoplasmic action in Chinese cabbage.

Seed Shattering: A Trait of Evolutionary Importance in Plants.

Seed shattering refers to the natural shedding of seeds when they ripe, a phenomenon typically observed in wild and weedy plant species. The timing and extent of this phenomenon varies considerably among plant species. Seed shattering is primarily a genetically controlled trait; however, it is significantly influenced by environmental conditions, management practices and their interactions, especially in agro-ecosystems. This trait is undesirable in domesticated crops where consistent efforts have been made to minimize it through conventional and molecular breeding approaches. However, this evolutionary trait serves as an important fitness and survival mechanism for most weeds that utilize it to ensure efficient dispersal of their seeds, paving the way for persistent soil seedbank development and sustained future populations. Weeds have continuously evolved variations in seed shattering as an adaptation under changing management regimes. High seed retention is common in many cropping weeds where weed maturity coincides with crop harvest, facilitating seed dispersal through harvesting operations, though some weeds have notoriously high seed shattering before crop harvest. However, high seed retention in some of the most problematic agricultural weed species such as annual ryegrass (Lolium rigidum), wild radish (Raphanus raphanistrum), and weedy amaranths (Amaranthus spp.) provides an opportunity to implement innovative weed management approaches such as harvest weed seed control, which aims at capturing and destroying weed seeds retained at crop harvest. The integration of such management options with other practices is important to avoid the rapid evolution of high seed shattering in target weed species. Advances in genetics and molecular biology have shown promise for reducing seed shattering in important crops, which could be exploited for manipulating seed shattering in weed species. Future research should focus on developing a better understanding of various seed shattering mechanisms in plants in relation to changing climatic and management regimes.

Fallow management input strategies for weed management in Florida cabbage production.

Fallow period weed management is an important Florida production consideration due to its duration and impact on the cash crop. Cover cropping is a valuable summer fallow period option for weed suppression. Sorghum-sudangrass is a commonly used, competitive, and allelopathic Florida summer cover crop. The effect of increased seeding rate, a herbicide application, and added fertilizer inputs during the fallow period on the cover crop, weed populations, and cabbage yield was explored and compared to nontreated and chemical fallow controls. Increased sorghum-sudangrass seeding rates had no effect on the resultant stand density or biomass compared to the standard seeding rate. Cover cropping did not consistently suppress purple nutsedge, Florida pusley, or wild radish and added fertilizer inputs produced variable results. S-metolachlor enhanced purple nutsedge suppression at low densities but did not improve grass, wild radish, and Florida pusley suppression. Increased fallow management inputs did not consistently enhance weed suppression or provide benefit to the cash crop. Sorghum-sudangrass suppressed Poaceae densities during the fallow period but did not adequately suppress nutsedge, wild radish, or Florida pusley densities over time. We conclude that weed management inputs should be focused on the cash crop and that enhanced management during the fallow period has limited benefit. © 2021 Society of Chemical Industry.

Bioherbicidal Potential of Eucalyptus and Clove Oil and their Combinations on Four Weedy Species

Essential oils of eucalyptus leaves and clove buds were isolated and tested for their bioherbicidal potential on different annual weed species. Gas Chromatography-Mass Spectrophotometry analysis (GC-MS) identified thirteen compounds representing around 87.11% of the total isolated eucalyptus oil. The main constituent was 1,8-cineole, which accounted for 68.15% of the total identified compounds. As for clove oil, eleven compounds were identified, representing 90.03% of the total compounds. Eugenol was the dominant compound and accounted for 73.89%. The bioherbicidal efficacy of the two oils and their combinations by three concentrations (2.5, 5, and 10%) were tested on four weedy species, namely Chenopodium album, Raphanus raphanistrum, Melilotus indicus, and Sisymbrium irio. The isolated oils significantly affected the dry weight and inhibited the seedling growth of the four weedy species. Using the two essential oils, individually or within their combinations, showed the highest bioherbicidal efficacy against the targeted weeds in comparison with the synthetic herbicide. In addition, utilization of the two essential oils as natural bioherbicides caused an electrolyte leakage as a result of membrane disruption and loss of integrity of weed seedling tissues. The results showed the possibility of using eucalyptus and clove essential oils individually or in combination as a desirable alternative to synthetic herbicides for sustainable weed management.

Weed control and soybean agronomic performance in response to application of sulfentrazone + diuron in pre-emergence

The use of pre-emergent herbicides is an important tool in weedmanagement. Sulfentrazone + diuron mixture was recently launched ontothe market. The objectiveof this work was to evaluate the weed control and the agronomic performance of soybean in response to application of sulfentrazone + diurondoses in pre-emergence. The experiment was conducted in Londrina PR, in an oxisol. The treatments were doses ofsulfentrazone + diuron (62 + 123, 123 + 245, 184 + 368, 245 + 490, 306 + 613 e 368 + 735 g a.i.ha-1). In addition to these treatments, isolated applications of sulfentrazone (245 g a.i.ha-1) and diuron (490 g a.i.ha-1) were evaluated, as well as a weedyand aweed-freecontrol. For the weed control, the wild radish(Raphanus raphanistrum)and itchgrass (Rottboellia cochinchinensis) emergencewere evaluated. In soybean, photosystem II (PSII)activity, stand, plant height, number of podsper plant, height of insertion of the first pod, number of nodes per plant, mass of a thousand grains and grain yield were evaluated. Results show that the mixture of sulfentrazone + diuron resulted in less than 50% wild radish control, regardless of the dose evaluated. However, for itchgrass, the control was greater than 90% in doses from 123 g sulfentrazone + 245g diurona.i.ha-1. Regarding thesoybeancrop, in doses from 245 g sulfentrazone + 490 g diuron a.i. ha-1 there was a greater number of pods per plant and higher grain yield, of about3,000 kg ha-1. The application of herbicides led to a transient inhibition of PSIIactivity, which did not result in a reduction in crop grainyield, indicating plant recovery. Therefore, the mixture of sulfentrazone + diuron is a good alternative for the weed management in pre-emergence of soybean, and should be positioned according to the history of fieldinfestation.

Design and Testing of Bioreceptive Porous Concrete: A New Substrate for Soilless Plant Growth

Porous concrete with a high void content has gained popularity in urban environments as it allows water to spread through its pores. Permeability is a desired characteristic when developing media for plant growth as it enables roots to spread and anchor themselves. This leads to the aim of this study, developing a porous concrete substrate for plant growth with a pH lower than that of standard concrete. The substrate incorporates recovered industrial byproducts from blast furnaces. The materials used in the design consist of a blast furnace slag binder, two proprietary alkali activators, quartz aggregates (2.0–3.2 mm in size), a void content of 30%, and a water to binder ratio of 0.295. Tomato (Solanum lycopersicum), radish (Raphanus raphanistrum), and romaine lettuce (Lactuva sativa) were seeded onto the slag porous concrete for a 28-day hydroponic experiment. The treatments with porous concrete substrates differed in concentrations of the nutrient solution: Hoagland normal (1×), double Hoagland (2×), and quintuple Hoagland (5×). Rockwool with a 1× nutrient solution was selected as the control treatment, a hydroponic standard for plant growth. The dry mass values of the 2× treatment and the control treatment were similar (P > 0.05). The largest dry mass of all treatments investigated was the radish in the 2× treatment at 125.4% of the control radish dry mass.

Analysis of Chemical Composition and In Vitro and In Vivo Antifungal Activity of Raphanus raphanistrum Extracts against Fusarium and Pythiaceae, Affecting Apple and Peach Seedlings.

The goal of this investigation was to evaluate the in vitro and in vivo efficiency of Raphanus raphanistrum extracts against Fusarium and Pythiaceae species associated with apple and peach seedling decline in Tunisian nurseries. A chemical composition of organic extracts was accomplished using liquid chromatography, thin layer chromatography, and gas chromatography analysis. The in vitro test of three aqueous extract doses of R. raphanistrum against some apple and peach decline agents showed its efficacy in reducing mycelia growth. The in vivo assay of fine powder of this plant on peach seedlings revealed that treatment 8-weeks before the inoculation and planting was more efficient than the treatment before one week. This experiment revealed that the root weight of peach seedlings inoculated by F. oxysporum was improved to 207.29%. For apple seedlings, the treatment 8 weeks before the inoculation and plantation was more efficient than the treatment one week before; it reduced the root browning index. The study of R. raphanistrum chemical composition and its efficiency showed that the glucosinolates products: nitrile (4-Hydroxy-3-(4-methylphenylthio) butane nitrile, benzene acetonitrile, 4-fluoro,butane nitrile, 4-hydroxy-3-[(4-methylphenyl) thio] nitrile), and thiocyanate molecules (thiocyanic acid, ethyle) are responsible for the anti-fungal activities.

Growth and fecundity of colonizing hybrid Raphanus populations are environmentally dependent.

Hybrid gene pools harbor more genetic variation than progenitor populations. Thus, we expect hybrid populations to exhibit more dynamic evolutionary responses to environmental variation. We ask how environmental variation experienced by adapted and transplanted populations influence the success of late-generation hybrid populations during invasion. For four generations, 20 wild (Raphanus raphanistrum) and 20 hybrid radish (R. sativus × R. raphanistrum) plant populations evolved under experimentally manipulated moisture conditions (dry, wet, control-sheltered, or control-unsheltered plots; i.e., evolutionary environment) in old fields near Toronto, Canada. We planted advanced-generation wild and hybrid radishes in sheltered plots and exposed them to either an evolutionary or a novel watering environment. To determine how soil moisture would influence invasion success, we compared the phenotype and fecundity of plants grown in these various environments. Hybridization produced larger plants. In wet environments, hybrid seedlings emerged more frequently and expressed higher photosynthetic activity. Low-moisture, novel conditions delayed and reduced seedling emergence frequency. Hybrid plants and those that evolved under relatively wet environments exhibited higher aboveground biomass. Hybrid plants from control-sheltered plots colonizing novel moisture environments were more fecund than comparable wild plants. Dry environments are less likely than other evolutionary environments to contribute colonists. However, relatively wet locations support the evolution of relatively fecund plants, especially crop-wild hybrid populations. Thus, our results provide a strong mechanistic explanation for variation in the relative success of crop-wild hybrids among study locations and a new standard for studies that assess the risk of crop-wild hybridization events.

Transgenerational Plasticity in Flower Color Induced by Caterpillars.

Variation in flower color due to transgenerational plasticity could stem directly from abiotic or biotic environmental conditions. Finding a link between biotic ecological interactions across generations and plasticity in flower color would indicate that transgenerational effects of ecological interactions, such as herbivory, might be involved in flower color evolution. We conducted controlled experiments across four generations of wild radish (Raphanus sativus, Brassicaceae) plants to explore whether flower color is influenced by herbivory, and to determine whether flower color is associated with transgenerational chromatin modifications. We found transgenerational effects of herbivory on flower color, partly related to chromatin modifications. Given the presence of herbivory in plant populations worldwide, our results are of broad significance and contribute to our understanding of flower color evolution.

Wild radish (Raphanus sativus var. hortensis f. raphanistroides) root extract protects neuronal cells by inhibiting microglial activation

External stimulus-induced activation of microglia plays an important role in the protection of neurons in the central nervous system; however, over-activation of microglia could cause neuronal damage, and it is implicated in the pathogenesis of neurodegenerative diseases. The aim of the present study was to investigate the effects of wild radish (Raphanus sativus var. hortensis f. raphanistroides) root extract (WRE) on microglial over-activation. Mouse microglia BV-2 cells and rat primary microglia were stimulated with lipopolysaccharide (LPS), treated with WRE, and analyzed for nitric oxide (NO) production, pro-inflammatory cytokine secretion, inducible NO synthase (iNOS) expression, and p38 kinase phosphorylation. Human neuroblastoma SH-SY5Y cells were treated with microglia-conditioned medium and analyzed for cell viability. Stimulation with LPS increased NO production and iNOS expression in BV-2 cells and primary microglia, but the treatment with WRE decreased both. Furthermore, WRE downregulated the mRNA expression and secretion of inflammatory cytokines interleukin-1 beta (IL-1β) and tumor necrosis factor alpha (TNF-α), and inhibited the phosphorylation of p38 in LPS-activated microglia. Treatment with the conditioned medium of LPS-induced BV-2 cells decreased the viability of SH-SY5Y cells, but the damaging effect was significantly alleviated in cells treated with the conditioned medium of LPS plus WRE-cultured microglia. This indicated that the WRE treatment of microglia could protect neuronal cells from microglial activation-induced neurotoxicity. WRE may be a potential food product to attenuate neuroinflammation via the inhibition of microglial over-activation, which can slow down the neurodegenerative processes in the brain.

Allelopathic Effects of Three Herb Species on Phytophthora cinnamomi, a Pathogen Causing Severe Oak Decline in Mediterranean Wood Pastures

The ability of three herbaceous plants (Diplotaxis tenuifolia (L.) DC., Eruca vesicaria L. and Raphanus raphanistrum L.) from Iberian wood pastures to reduce Phytophthora cinnamomi Rands pathogen populations through allelopathic relationships is studied. The inhibitory capacity of their aqueous root extracts (AREs) on mycelial growth and production of P. cinnamomi reproductive structures is analysed in vitro. In addition, Quercus seedlings were grown in infested by P. cinnamomi-soils and with the presence or absence of allelopathic and susceptible herb species to the pathogen to assess the defensive chemical response of Quercus seedlings through their leaf phenolic compounds. Results show a strong inhibitory capacity of AREs on P. cinnamomi activity in vitro and a protective effect of these herb species on Quercus plants against P. cinnamomi in vivo. D. tenuifolia would be especially suited for biological control in the pathogen suppression.

Effects of Tetracyclines on Primary Root Length and Chlorophyll Contents of Vegetable Crops

By increasing the use of antibiotics, it is concerned that unexpectedly contaminated the effect of antibiotics occurs in agricultural soil. In this study, we investigated the impact of antibiotics on the early stages of crop growth using lettuce (Lactuca sativa), cabbage (Brassica campestris), and radish (Raphanus raphanistrum). These crops were grown on agar plates vertically without antibiotics (0 mg/L) and with tetracycline 5 (TC5), 10 (TC10), and 20 (TC20) mg/L, chlortetracycline 5 (CTC5), 10 (CTC10), and 20 (CTC20) mg/L, and oxytetracycline 5 (OTC5), 10 (OTC10), and 20 (OTC20) mg/L at 20°C for five days. Root length of all crops inhibited in a concentration-dependent manner except for cabbage of OTC treatment. For lettuce, root length (cm) showed an average 6.06 and 1.39 upon control (0 mg/L) and TC20, respectively. Similarly, cabbage and radish exhibited an average 7.20 and 5.47, respectively, without TCs whereas TC20 inhibits the root length down to 2.26 and 1.59, respectively. The chlorophyll contents of cabbage and radish reduced as increased antibiotic concentration. Interestingly, chlorophyll contents of lettuce did not show significantly different. Therefore, we suggest future research directions by showing the effect of antibiotics on crops. TC effects on the cabbage root development and chlorophyll contents of Brassica campestris.

Small Functional Foods: Comparative Phytochemical and Nutritional Analyses of Five Microgreens of the Brassicaceae Family.

Microgreens are the seedlings of herbs and vegetables which are harvested at the development stage of their two cotyledonary leaves, or sometimes at the emergence of their rudimentary first pair of true leaves. They are functional foods, the consumption of which is steadily increasing due to their high nutritional value. The species of the Brassicaceae family are good sources of bioactive compounds, with a favorable nutritional profile. The present study analyzed some phytochemical compounds with nutritional values, such as chlorophylls, polyphenols, carotenoids, anthocyanins, ascorbic acid, total and reducing sugars, and the antioxidant activity of five Brassicaceae species: broccoli (Brassica oleracea L.), daikon (Raphanus raphanistrum subsp. sativus (L.) Domin), mustard (Brassica juncea (L.) Czern.), rocket salad (Eruca vesicaria (L.) Cav.), and watercress (Nasturtium officinale R.Br.). Broccoli had the highest polyphenol, carotenoid and chlorophyll contents, as well as a good antioxidant ability. Mustard was characterized by high ascorbic acid and total sugar contents. By contrast, rocket salad exhibited the lowest antioxidant content and activity. The essential oil (EO) composition of all of these species was determined in order to identify their profile and isothiocyanates content, which are compounds with many reported health benefits. Isothiocyanates were the most abundant group in broccoli (4-pentenyl isothiocyanate), mustard (allyl isothiocyanate), and watercress (benzyl isothiocyanate) EOs, while rocket salad and daikon exhibited higher contents of monoterpene hydrocarbons (myrcene) and oxygenated diterpenes (phytol), respectively. Broccoli microgreens exhibited the overall best nutritional profile, appearing as the most promising species to be consumed as a functional food among those analyzed.

ANTI-CHOLOSETEROL ACTIVITIES OF WHITE (RAPHANUS RAPHANISTRUM) AND RED (RAPHANUS SATIVUS) RADISH ROOTS

Objective: The purpose of this research is to explore the in vitro activities of white (Raphanus raphanistrum) and red (Raphanus sativus) radish root ethanol extract in decreasing cholesterol levels.
 Methods: Ultrasonification method was used in obtaining 96% ethanol extract of white and red radish root. The cholesterol levels were analyzed by visible spectrophotometry, which was validated using Lieberman-Buchard reagents. The decreased cholesterol levels were converted into IC50 values.
 Results: The results showed that the IC50 of 96% white and red radish root ethanol extracts were 743.7 and 634.7 µg/ml, respectively. The results of statistical analysis using the T-test obtained a significant value greater than the probability value (P) of 0.05.
 Conclusion: Therefore, it was concluded that the activities of 96% ethanol extract of white and red radish roots did not have a significant ability to reduce the in vitro cholesterol levels.

The adaptive value of flowering time in wild radish (Raphanus raphanistrum)

AbstractHarvest weed seed control (HWSC) is a weed management technique that intercepts and destroys weed seeds before they replenish the soil weed seedbank and can be used to control herbicide-resistant weeds in global cropping systems. Wild radish (Raphanus raphanistrum L.) is a problematic, globally distributed weed species that is considered highly susceptible to HWSC, as it retains much of its seed on the plant during grain harvest. However, previous studies have demonstrated that R. raphanistrum is capable of adapting its life cycle, in particular its flowering time, to allow individuals more time to mature and potentially shed seeds before harvest, thereby evading HWSC interception. This study compared the vegetative growth plus physiological and ecological fitness of an early-flowering R. raphanistrum biotype with an unselected genetically related biotype to determine whether physiological costs of early flowering exist when in competition with wheat (Triticum aestivum L.). Early flowering time adaptation in R. raphanistrum did not change the relative growth rate or competitive ability of R. raphanistrum. However, the height of first flower was reduced in the early flowering time–selected population, indicating that this population would retain more pods below the typical harvest cutting height (15 cm) used in HWSC. The presence of wheat competition (160 to 200 plants m−2) increased flowering height in the early flowering time–selected population, which would likely increase the susceptibility of early-flowering R. raphanistrum plants to HWSC. Overall, early-flowering adaption in R. raphanistrum is a possible strategy to escape being captured by the HWSC; however, increasing crop competition is likely to be an effective strategy to maintain the effectiveness of HWSC.

Deterministic risk assessment of firefighting water additives to terrestrial organisms

Firefighting water additives are used to increase the rate at which fires can be extinguished. The majority of ecotoxicological research has focused on firefighting formulations containing perfluorinated compounds as additives, due to the persistence and bioaccumulative nature of the perfluorinated constituents. A number of relatively new additives have come on the market to replace the products containing perfluorinated compounds. The potential effect of these new additives on the environment has been largely unstudied. This study investigated the toxicity of six firefighting water additives: Eco-Gel™, ThermoGel 200L™, FireAde™, Fire-Brake™, Novacool Foam™, and F-500™ to terrestrial biota. Terrestrial organisms could be exposed to firefighting water additives through leaching into soil and/or runoff following a firefighting event or through direct aerial application during a forest fire. Toxicity to three plant species was assessed through seedling germination and emergence tests: Fagopyrum esculentum (buckwheat), Raphanus raphanistrum subsp. sativus (radish), and Rudbeckia hirta (black-eyed Susan). The effects of firefighting water additives on three soil invertebrates, the collembolan Folsomia candida, the earthworms Eisenia andrei, and Dendrodrilus rubidus, were also investigated using static acute tests to estimate EC50/LC50s. The concentration that resulted in a 50% reduction in survival (LC50) for the acute toxicity tests conducted with F. candida ranged from 3 (Eco-Gel) to 0.175% (Novacool) by volume. Comparatively, the acute toxicity of two firefighting water additives to D. rubidus could not be determined, as a 50% reduction in survival was not observed. A number of firefighting water additives were found to pose a hazard to terrestrial organisms based on a worst-case exposure scenario of direct application at the greatest recommended application rate for a class A fire (e.g., wood, paper). The firefighting water additive F-500 was found to pose a hazard (HQ ≥ 1) for all species tested, except for the acute test conducted with D. rubidus. Comparatively, Eco-Gel posed a hazard for only the acute and chronic tests with F. candida. This study represents the first comparative deterministic risk assessment of firefighting water additives to terrestrial ecosystems.

Tree resin as a cultivation strategy under water deficit

ABSTRACT The search for alternatives that enable the improvement of the soil water retention capacity should focus on a better water use by cultivated plants. This study aimed to evaluate the effect of natural tree resin rates and irrigation levels on the cotton (intermediate cycle) and wild radish (short cycle) crops. Two experiments were conducted in a completely randomized design, in a 5 × 5 factorial arrangement, with three replications and five tree resin rates (0, 0.67, 1.33, 2.00 and 2.67 g plant-1), five soil water tensions (15, 30, 45, 60 and 75 kPa) for cotton plants and five irrigation water levels (40, 60, 80, 100 and 120 % of the ETc) for wild radish plants. The plant height, stem diameter and number of leaves were evaluated at 93 days after sowing (DAS) for the cotton plants; while the plant height, root diameter and number of leaves were evaluated at 30 DAS for the wild radish plants, as well as quantified the shoot and root dry weights of both plant species. The application of tree resin reduces the susceptibility of the crop to water deficit, being 2.7 g plant-1 the highest recommended rate to improve the plant development. The use of tree resin increases the water-use efficiency in cotton and wild radish crops in up to 0.68 g L-1 and 69.6 g L-1, respectively.

Target‐site resistance and cross‐resistance to ALS‐inhibiting herbicides in radish and wild radish biotypes from Brazil

AbstractRadish (Raphanus sativus L.) and wild radish (R. raphanistrum L.) are troublesome agricultural weeds in several areas worldwide, with populations resistant to acetolactate synthase (ALS) inhibitor herbicide. Information on the mechanisms of resistance is important for management and developing novel solutions to control resistant populations. The objective of this work was to determine the ALS‐resistance mechanisms in radish and wild radish biotypes resistant to ALS‐inhibiting herbicides. Resistance levels were determined by dose‐response curve using several rates of metsulfuron‐methyl herbicide in susceptible (JUC1) and resistant (JUC2, CRA3) radish, and susceptible (CAF1) and resistant (CAF2, CAF3) wild radish biotypes. The mechanism was evaluated by the in vitro activity of the ALS enzyme with imazapic herbicide and ALS gene sequencing. All resistant biotypes were insensitive to metsulfuron‐methyl and imazapic herbicides. The rate of metsulfuron‐methyl to reduce 50% growth of the plants (GR50) were 17‐ to 60‐fold (JUC2, CRA3) and 9‐ to 21‐fold (CAF2 and CAF3) higher than the susceptible biotypes of radish and wild radish, respectively. One‐point mutation in the ALS gene, Trp‐574‐Leu, was found in all resistant radish biotypes, whereas a second point mutation, Ala‐360‐Ser, was found in CAF2, CAF3, and JUC2 resistant biotypes. Changes in kinetic parameters of the ALS enzyme were found in all resistant biotypes evaluated, causing reduction of the herbicide affinity in the target‐site of action. Trp‐574‐Leu amino acid substitution resulted in resistance to sulfonylurea, imidazolinone, and triazolopyrimidine groups, with the survival greater than 75% of the plants, depending on the herbicide applied at labeled rate.

К синтаксономии сегетальной растительности Среднего Урала

The decrease in the crop area and changes in their ratio have led to changes in weed vegetation in the Middle Urals, where its cenoflora was studied relatively well (Tretyakova, 2006; Tretyakova, Kondratkov, 2018; Kondratkov, Tretyakova, 2018; 2019 a, b), while community diversity so far has not yet been assessed. The first results of the ecological and floristic classification of basic crop communities (wheat, barley, oats, corn, potatoes, peas, rapeseed etc.) in six botanical and geographical regions of the taiga and forest-steppe zones (Kulikov et al., 2013) within the Sverdlovsk region, based on the analysis of 160 relevés performed by A. S. Tretyakova, P. V. Kondratkov and N. Yu. Grudanov in 2019, are presented. Communities are classified within the order Aperetalia spicae-venti J. Tx. et Tx. in Malato-Beliz et al. 1960 of the class Papaveretea rhoeadis S. Brullo et al. 2001 nom. conserv. propos. and assigned to the alliance Scleranthion annui (Kruseman et Vlieger 1939 nom. conserv. propos.) Sissingh in Westhoff et al. 1946), which represents the most mesophytic types of weed vegetation in the Urals. Three associations allocated in alliance (two for the first time): Solano nigri–Erodietum cicutarii ass. nov. hoc loco (Table 2, syntaxon 7; Table 4); nomenclature type (holotypus hoc loco) — Table 4, rel. 11 (number in database — 25): Sverdlovsk Region, Sysertskiy district, Kunarskoe village environs, 23.07.2019, authors — A. S. Tretyakova, P. V. Kondratkov);Lamio amplexicaulis–Stellarietum mediae ass. nov. hoc loco (Table 2, syntaxon 8; table 5; nomenclature type (holotypus hoc loco) — Table 5, rel. 10 (number in database — 27): Sverdlovsk Region, Sysertskiy district, Shaidurovo village environs, 22.07.2019, authors — A. S. Tretyakova, P. V. Kondratkov); ass. Euphorbio helioscopiae–Fumarietum officinalis Khasanova et al. 2018. The last one includes two variants. Two unranked communities are also described. Distribution areas of syntaxa cover the southern taiga and pre-forest-steppe pine-birch forests subzones of the taiga zone and the northern forest-steppe subzone of the forest-steppe zone. Habitats are confined mainly to gray forest soils, in rare cases — leached chernozems. The mostly wide distributed is the ass. Euphorbio helioscopiae-Fumarietum officinalis, also common to the south of the study area, in the Republic of Bashkortostan. Аss. Lamio amplexicaulis–Stellarietum mediae is identified in five botanical and geographical districts within the Sverdlovsk region. The confluence with crops and the accompanying system of agriculturе is different. The species composition of the established syntaxa was compared with the associations of the alliance Scleranthion annui described earlier in the Republic of Bashkortostan. The species richness of the latter is generally higher. Differences in species composition of diagnostic groups were revealed. There is decreasing of constancy of Tripleurospermum inodorum, Centaurea cyanus, Polygonum aviculare, Raphanus raphanistrum in the cenoflora of the first one, and both diagnostic species of the more xerophytic alliance Caucalidion lappulae von Rochow 1951 (Galeopsis bifida, Persicaria lapathifolia, Silene noctiflora, Galeopsis ladanum, Melilotus officinalis),apophytes of meadow pasture and forest edges (Medicago lupulina, Trifolium hybridum, Trifolium medium, Achillea millefolium,etc.), xeromesiphytic species (Avena fatua, Amaranthus retroflexus, Setaria viridis, Euphorbia virgata). The latter is probably associated with significant reduction in the field area of some crops (sunflower, flax, etc.). The differences in species composition and ecology of the compared syntaxa are illustrated by the results of ordination analysis. Weed communities of the Southern Urals are localized on the left side of the DCA-ordination diagram, these of the Middle Urals — on the right one. There are changes from the most xerophytic communities of the ass. Linario vulgari-Lactucetum serriolae to the most mesophytic ones of associations Lamio amplexicaulis–Stellarietum mediae and Euphorbio helioscopiae–Fumarietum officialalinae along the first axis. The second axis reveals the change in species composition under the influence of the agronomic factor — culture and the corresponding agricultural system and communities of winter cereals (associations Consolido regali–Centaureetum cyanae and Galeopsetum bifidae) are replaced by communities of spring cereals and row crops (corn, potatoes, peas, rapeseed), which are assigned to the associations Linario vulgari–Lactucetum serriolae and Solanо nigri–Erodietum cicutarii.