The silver bullet that wasn't: Rapid agronomic weed adaptations to glyphosate in North America.

The rapid adoption of glyphosate-resistant crops at the end of the 20th century caused a simplification of weed management that relied heavily on glyphosate for weed control. However, the effectiveness of glyphosate has diminished. A greater understanding of trends related to glyphosate use will shed new light on weed adaptation to a product that transformed global agriculture. Objectives were to (1) quantify the change in weed control efficacy from postemergence (POST) glyphosate use on troublesome weeds in corn and soybean and (2) determine the extent to which glyphosate preceded by a preemergence (PRE) improved the efficacy and consistency of weed control compared to glyphosate alone. Herbicide evaluation trials from 24 institutions across the United States of America and Canada from 1996 to 2021 were compiled into a single database. Two subsets were created; one with glyphosate applied POST, and the other with a PRE herbicide followed by glyphosate applied POST. Within each subset, mean and variance of control ratings for seven problem weed species were regressed over time for nine US states and one Canadian province. Mean control with POST glyphosate alone decreased over time while variability in control increased. Glyphosate preceded by a labeled PRE herbicide showed little change in mean control or variability in control over time. These results illustrate the rapid adaptation of agronomically important weed species to the paradigm-shifting product glyphosate. Including more diversity in weed management systems is essential to slowing weed adaptation and prolonging the usefulness of existing and future technologies.

Uptake and Discontinuation of Pre-Exposure Prophylaxis Among Uninsured Transgender and Cisgender Women: A Public-Private Partnership Model in North Carolina.

HIV pre-exposure prophylaxis (PrEP) remains underutilized among cis and trans women. The PrEP Initiative Program (PIP) is a novel public-private partnership implemented at 12 local clinics in North Carolina. PIP provides HIV/sexually transmitted infection (STI) testing and clinical and laboratory monitoring for PrEP to uninsured/underinsured clients. We sought to understand service-related differences among both cis and trans women enrolled in PIP, including STIs diagnoses, clinic type, sources of referral, services needed, and reasons for PrEP discontinuation. The Kaplan-Meier curves display retention on PrEP over the duration of the program. Since 2018, 142 women (cis n = 113; trans n = 29) enrolled, and 136 started PrEP. The majority were ages 25-34 years (31.7%) or 18-24 years (29.6%), Black (57.8%) or Latinx (24.7%). Approximately 20.6% of recipients reported at least one STI while enrolled. Overall, trans women requested fewer services than cis women. After accounting for the amount of time each patient was taking PrEP, there were higher rates of trans women diagnosed with syphilis than cis women. Rates of persons with other STIs were not notably different between trans and cis women. Clinic access varied by gender: 69% of trans women were enrolled at only one site. Trans women were retained significantly longer: The Kaplan-Meier adjusted median time to discontinuation was 560 and 238 days for trans and cis women, respectively. PIP successfully reached historically marginalized and uninsured cis and trans women who may benefit from PrEP. Further investigations into factors contributing to recruitment and retention of women in HIV prevention programs are needed.

Mutual-information based optimal experimental design for hyperpolarized [Formula: see text]C-pyruvate MRI.

A key parameter of interest recovered from hyperpolarized (HP) MRI measurements is the apparent pyruvate-to-lactate exchange rate, [Formula: see text], for measuring tumor metabolism. This manuscript presents an information-theory-based optimal experimental design approach that minimizes the uncertainty in the rate parameter, [Formula: see text], recovered from HP-MRI measurements. Mutual information is employed to measure the information content of the HP measurements with respect to the first-order exchange kinetics of the pyruvate conversion to lactate. Flip angles of the pulse sequence acquisition are optimized with respect to the mutual information. A time-varying flip angle scheme leads to a higher parameter optimization that can further improve the quantitative value of mutual information over a constant flip angle scheme. However, the constant flip angle scheme, 35 and 28 degrees for pyruvate and lactate measurements, leads to an accuracy and precision comparable to the variable flip angle schemes obtained from our method. Combining the comparable performance and practical implementation, optimized pyruvate and lactate flip angles of 35 and 28 degrees, respectively, are recommended.

Defining the Current Deployment of Neonatal Infusion Pumps in Low- and Lower-Middle-Income Countries: A Rapid Review.

There has been limited review of the reported deployment of infusion pumps in low- and lower-middle-income countries. This paper aims to identify the current distribution of infusion pumps in low- and lower-middle-income countries (LLMICs) used to treat neonates. A rapid review was conducted using material sourced from ProQuest, Pubmed, Web of Science, and IEEE Xplore. Twenty-six search results met the inclusion criteria. Within these, 41 neonatal healthcare facilities were discussed with 17 of the facilities having infusion pumps available, 13 limited access, and 11 none. Infusion pump use remains limited in Sub-Saharan Africa so efforts should be made to deploy specialist neonatal care improvement packages, potentially including infusion pumps designed for LLMICs. The effects of COVID-19, to neonatal care LLMICs, should be accessed to ensure progress has not regressed. These proposals aim to aid in the continued improvement of neonatal care globally and reduce newborn mortalities.

Risk Factors and Laboratory Findings Associated With Diabetic Ketoacidosis in Hospitalized Pediatric Patients.

BACKGROUND: Diabetic ketoacidosis (DKA), the most serious and acute complication of type 1 diabetes, has an incidence of 6%-8% among known pediatric type 1 diabetes patients, although risk factors associated with severe DKA in the pediatric population are poorly understood [1]. METHOD: A single-institution, retrospective chart analysis of pediatric DKA patients admitted to our pediatric intensive care unit (PICU) was conducted in South Alabama between October 2017 and April 2021. Laboratory findings were obtained from venous samples collected from the patients on admission. RESULTS: Of 429 admissions, 256 unique patients were admitted with DKA to PICU during the 3.5-year period; 55.9% of them were males. The median (IQR) age of the patients was 12 (10-15) years, and their median HbA1c level was 11.02 (10%-12%), which was similar to Medicaid and private insurance statistics (11.1 [9.87-12.2] vs 11 [9.65-12], p = 0.4). Serum pH on presentation was 7.17 (7.08-7.25), and serum bicarbonate was 10 (7-14) mmol/L. White blood cell (WBC) count, platelet count, and mean platelet volume (MPV) had a negative correlation with serum pH (r = -0.52, p < 0.001, r = -0.25, p = 0.01 and r = -0.11, p = 0.03, respectively). The blood urea nitrogen (BUN):creatinine ratio had a positive correlation with serum pH (r = 0.16, p < 0.001). Twenty-nine admissions (6.8%) with a median age of 16 (13-17) years required imaging for altered mental status, and none of these patients were diagnosed with cerebral edema. CONCLUSION: DKA is associated with noncompliance among pediatric patients, irrespective of their type of insurance. Markers of oxidative stress (WBC, platelets, and MPV) were associated with increased severity of DKA. The BUN:creatinine ratio may not provide accurate hydration status among DKA patients. Clinicians need to have a lower threshold for head imaging among younger patients.

An online survey and interview of GPs in the UK for assessing their satisfaction regarding the medical training curriculum and NICE guidelines for the management of menopause.

BACKGROUND: The UK is home to 13 million menopausal women. The aim of this study was to determine the views of GPs on their levels of confidence and comfort when advising or treating menopausal women and assess the need for further training. METHOD: An anonymous online questionnaire was sent out to GPs working within the NHS across the UK between January 2021 and March 2021. The questionnaire was circulated via GP e-mail lists, Facebook, and LinkedIn, and included an option for respondents to volunteer for a semi-structured interview. RESULTS: The questionnaire had 173 responses. 52% of GPs indicated that they were not offered enough support to be able to advise and treat women with menopausal symptoms appropriately. 77.5% of GPs expressed that there is a need to improve training provided on menopause in medical school and GP training. 60.7% of GPs felt comfortable managing menopausal women and offering them management options. 22.5% of the respondents felt that the NICE guidelines are easy and clear guidance for clinical practice. Five GPs were further interviewed, and the analysis of the responses showed the perceived need by the GPs for improvements in medical training regarding menopause. CONCLUSION: There is a need for better support and medical training for GPs to help them advice and treat women with menopausal symptoms. This is key for ensuring that every woman in the UK feels supported in their journey during the menopausal transition and is offered evidence-based advice to help them make informed decisions.

Severe liver dysfunction in a toddler receiving nonprescription phytocannabinoid.

BACKGROUND: Nonprescription cannabis products are becoming widely available and being promoted for various health conditions. Safety profile of these products apart from psychoactive effects has not been studied and published well. Liver dysfunction is well described in literature with high doses of recreational tetrahydrocannabinol and cannabidiol products but not with nonprescription phytocannabinoids products used for various medicinal values. CASE SUMMARY: A 2-year-old unimmunized male with infantile spasms and refractory seizures, managed with clobazam and zonisamide, presented for respiratory illness and incidentally diagnosed with severe liver dysfunction with elevated coagulation markers. He did not manifest any clinical signs of liver failure. On further review, it was found that parents were using nonprescription phytocannabinoids (hemp extract) for his neurological condition. He required supportive care for his liver dysfunction, and liver enzymes down trended gradually after holding his phytocannabinoid products. The World Health Organization-Uppsala Monitoring Centre approach puts the presentation as probable/likely category of adverse reaction for liver dysfunction with phytocannabinoid ingestion. PRACTICAL IMPLICATIONS: The case we present shows the detrimental effects of over-the-counter phytocannabinoid products, which could point toward the role of phytocannabinoids in this pathophysiology. The case highlights the importance of awareness of potential life-threatening consequences of these products and educating the patient and the caregivers of these risks. The case also emphasizes the need for serial liver enzymes monitoring for patients receiving these therapies as well as extensive research focusing on safety profile of these products in terms of different organ system affection other than their psychoactive potential.

OxVent: Design and evaluation of a rapidly-manufactured Covid-19 ventilator.

BACKGROUND: The manufacturing of any standard mechanical ventilator cannot rapidly be upscaled to several thousand units per week, largely due to supply chain limitations. The aim of this study was to design, verify and perform a pre-clinical evaluation of a mechanical ventilator based on components not required for standard ventilators, and that met the specifications provided by the Medicines and Healthcare Products Regulatory Agency (MHRA) for rapidly-manufactured ventilator systems (RMVS). METHODS: The design utilises closed-loop negative feedback control, with real-time monitoring and alarms. Using a standard test lung, we determined the difference between delivered and target tidal volume (VT) at respiratory rates between 20 and 29 breaths per minute, and the ventilator's ability to deliver consistent VT during continuous operation for >14 days (RMVS specification). Additionally, four anaesthetised domestic pigs (3 male-1 female) were studied before and after lung injury to provide evidence of the ventilator's functionality, and ability to support spontaneous breathing. FINDINGS: Continuous operation lasted 23 days, when the greatest difference between delivered and target VT was 10% at inspiratory flow rates >825 mL/s. In the pre-clinical evaluation, the VT difference was -1 (-90 to 88) mL [mean (LoA)], and positive end-expiratory pressure (PEEP) difference was -2 (-8 to 4) cmH2O. VT delivery being triggered by pressures below PEEP demonstrated spontaneous ventilation support. INTERPRETATION: The mechanical ventilator presented meets the MHRA therapy standards for RMVS and, being based on largely available components, can be manufactured at scale. FUNDING: Work supported by Wellcome/EPSRC Centre for Medical Engineering,King's Together Fund and Oxford University.

Genomic-based epidemiology reveals independent origins and gene flow of glyphosate resistance in Bassia scoparia populations across North America.

Genomic-based epidemiology can provide insight into the origins and spread of herbicide resistance mechanisms in weeds. We used kochia (Bassia scoparia) populations resistant to the herbicide glyphosate from across western North America to test the alternative hypotheses that (i) a single EPSPS gene duplication event occurred initially in the Central Great Plains and then subsequently spread to all other geographical areas now exhibiting glyphosate-resistant kochia populations or that (ii) gene duplication occurred multiple times in independent events in a case of parallel evolution. We used qPCR markers previously developed for measuring the structure of the EPSPS tandem duplication to investigate whether all glyphosate-resistant individuals had the same EPSPS repeat structure. We also investigated population structure using simple sequence repeat markers to determine the relatedness of kochia populations from across the Central Great Plains, Northern Plains and the Pacific Northwest. We found that the original EPSPS duplication genotype was predominant in the Central Great Plains where glyphosate resistance was first reported. We identified two additional EPSPS duplication genotypes, one having geographical associations with the Northern Plains and the other with the Pacific Northwest. The EPSPS duplication genotype from the Pacific Northwest seems likely to represent a second, independent evolutionary origin of a resistance allele. We found evidence of gene flow across populations and a general lack of population structure. The results support at least two independent evolutionary origins of glyphosate resistance in kochia, followed by substantial and mostly geographically localized gene flow to spread the resistance alleles into diverse genetic backgrounds.

Effect of EPSPS gene copy number and glyphosate selection on fitness of glyphosate-resistant Bassia scoparia in the field.

The widespread evolution of glyphosate-resistant (GR) Bassia scoparia in the U.S. Great Plains poses a serious threat to the long-term sustainability of GR sugar beet. Glyphosate resistance in B. scoparia is due to an increase in the EPSPS (5-enolpyruvyl-shikimate-3-phosphate) gene copy number. The variation in EPSPS gene copies among individuals from within a single GR B. scoparia population indicated a differential response to glyphosate selection. With the continued use of glyphosate in GR sugar beet, the effect of increasing glyphosate rates (applied as single or sequential applications) on the fitness of GR B. scoparia individuals with variable EPSPS gene copies was tested under field conditions. The variation in EPSPS gene copy number and total glyphosate rate (single or sequential applications) did not influence any of the reproductive traits of GR B. scoparia, except seed production. Sequential applications of glyphosate with a total rate of 2214 g ae ha-1 or higher prevented seed production in B. scoparia plants with 2-4 (low levels of resistance) and 5-6 (moderate levels of resistance) EPSPS gene copies. Timely sequential applications of glyphosate (full recommended rates) can potentially slow down the evolution of GR B. scoparia with low to moderate levels of resistance (2-6 EPSPS gene copies), but any survivors (highly-resistant individuals with ≥ 8 EPSPS gene copies) need to be mechanically removed before flowering from GR sugar beet fields. This research warrants the need to adopt ecologically based, multi-tactic strategies to reduce exposure of B. scoparia to glyphosate in GR sugar beet.

Biologically-Based Mathematical Modeling of Tumor Vasculature and Angiogenesis via Time-Resolved Imaging Data.

Tumor-associated vasculature is responsible for the delivery of nutrients, removal of waste, and allowing growth beyond 2-3 mm3. Additionally, the vascular network, which is changing in both space and time, fundamentally influences tumor response to both systemic and radiation therapy. Thus, a robust understanding of vascular dynamics is necessary to accurately predict tumor growth, as well as establish optimal treatment protocols to achieve optimal tumor control. Such a goal requires the intimate integration of both theory and experiment. Quantitative and time-resolved imaging methods have emerged as technologies able to visualize and characterize tumor vascular properties before and during therapy at the tissue and cell scale. Parallel to, but separate from those developments, mathematical modeling techniques have been developed to enable in silico investigations into theoretical tumor and vascular dynamics. In particular, recent efforts have sought to integrate both theory and experiment to enable data-driven mathematical modeling. Such mathematical models are calibrated by data obtained from individual tumor-vascular systems to predict future vascular growth, delivery of systemic agents, and response to radiotherapy. In this review, we discuss experimental techniques for visualizing and quantifying vascular dynamics including magnetic resonance imaging, microfluidic devices, and confocal microscopy. We then focus on the integration of these experimental measures with biologically based mathematical models to generate testable predictions.

Fulminant Septic Shock with Pasteurella multocida in a Young Infant: No Bite, Scratch, or Lick!

This is a case of Pasteurella multocida septic shock encountered in a 7-week-old infant without any bites, scratch marks, or history of licks by pet animals (dog and cats in household). The infant required 3 days of vasopressor support and 4 days of mechanical ventilation to achieve normal hemodynamics. This is an unidentified route of transmission and our literature search for this topic discovered reported cases of life-threatening presentation with Pasteurella infections in the absence of a bite or any form of invasive contact with animals. We believe that this is an important public safety message to restrict animal contact of young infants to prevent severe infection.

Electromagnetic Versus Blind Guidance of a Postpyloric Feeding Tube in Critically Ill Children.

BACKGROUND AND OBJECTIVES: Postpyloric feeding tube placement is a time-consuming procedure associated with multiple attempts and radiation exposure. Our objective with this study is to compare the time, attempts, and radiation exposure using the electromagnetic versus blind method to place a postpyloric feeding tube in critically ill children. Our hypothesis is that using electromagnetic guidance decreases the procedure time, number of x-rays, and number of attempts, compared to the blind method. METHODS: Eleven pediatric nurses participated in a randomized controlled intention-to-treat study at an academic pediatric medical, surgical, and congenital cardiac ICU. University of Texas Health Epidemiology and Biostatistics generated a randomization sequence with sealed envelopes. A standard (2-sided) F-test of association between the electromagnetic and blind method yielded 40 subjects with 86% power. Data were analyzed with Fisher's exact test for categorical variables and the Wilcoxon rank test for continuous variables, with data documented as median (interquartile range [IQR]). RESULTS: We randomly assigned 52 patients to either the electromagnetic (n = 28) or blind method (n = 24). The number of attempts and radiographs was at a median of 2 (IQR: 1-2.25) using the blind method, compared to the electromagnetic method at a median of 1 (IQR: 1.0-1.0; P = .001). Successful guidance was 96.4% with the electromagnetic method, compared to only 66.7% with the blind technique (P = .008). The total time required was 2.5 minutes (IQR: 2.0-7.25) with the electromagnetic method, compared to 19 minutes (IQR: 9.25-27.0) for the blind method (P = .001). CONCLUSIONS: Electromagnetic guidance is a superior, faster, and overall safer method to place a postpyloric feeding tube in critically ill children.

Effect of emergence time on growth and fecundity of Rapistrum rugosum and Brassica tournefortii in the northern region of Australia.

Weeds from Brassicaceae family are a major threat in many crops including canola, chickpea, cotton and wheat. Rapistrum rugosum (L) All. and Brassica tournefortii Gouan. are two troublesome weeds in the northern region of Australia. In order to examine their phenology of these weeds, a pot study was conducted in 2018 at the Research Farm of the University of Queensland, Gatton campus with two populations sourced from high (Gatton) and medium (St George) rainfall areas of the northern grain region of Australia. Planting was carried out monthly from April to September, and the growth, flowering and seed production were evaluated. Maximum growth and seed production were observed in weeds planted in April, compared to other planting dates. Biomass of R. rugosum and B. tournefortii was reduced by 85% and 78%, respectively, as a result of the delay in planting from April to July. R. rugosum and B. tournefortii produced more than 13,000 and 3500 seeds plant-1, respectively, when planted in April and seed production was reduced by > 84% and > 76% when planted in July. No significant differences were observed between populations of both weeds for plant height, number of leaves and biomass, however, the medium rainfall population of R. rugosum produced more seeds than the high rainfall population when planted in April. The results of this study suggest that, although R. rugosum and B. tournefortii were able to emerge in a wider time frame, the growth and seed production were greatest when both weeds were planted in April and there was concomitant reduction in growth attributes when planted in the subsequent months, indicating that management of these weeds early in the cropping season is a prerequisite to population reduction and the mitigation of crop yield losses.

Plasmapheresis for Rescue in Severe Encephalopathy and Multiorgan Failure from Fulminant Influenza (H3N2) Infection.

We are presenting a case of 4-years-old previously healthy male with coma, severe acute hepatitis and multiorgan failure in presence of Influenza infection. Literature review highlighted an immune-mediated pathophysiology for such presentations so the child underwent a trial of plasmapheresis which resulted in a rapid clinical improvement and child was discharge in his baseline neurologic status by day 14.

Bayesian-based predictions of COVID-19 evolution in Texas using multispecies mixture-theoretic continuum models.

We consider a mixture-theoretic continuum model of the spread of COVID-19 in Texas. The model consists of multiple coupled partial differential reaction-diffusion equations governing the evolution of susceptible, exposed, infectious, recovered, and deceased fractions of the total population in a given region. We consider the problem of model calibration, validation, and prediction following a Bayesian learning approach implemented in OPAL (the Occam Plausibility Algorithm). Our goal is to incorporate COVID-19 data to calibrate the model in real-time and make meaningful predictions and specify the confidence level in the prediction by quantifying the uncertainty in key quantities of interests. Our results show smaller mortality rates in Texas than what is reported in the literature. We predict 7003 deceased cases by September 1, 2020 in Texas with 95 % CI 6802-7204. The model is validated for the total deceased cases, however, is found to be invalid for the total infected cases. We discuss possible improvements of the model.

A Quality Improvement Initiative to Reduce Surgical Site Infections in Patients Undergoing Delayed Sternal Closure After Pediatric Cardiac Surgery.

Sternal wound infections (SWI) in delayed sternal closure (DSC) patients are a healthcare burden after congenital heart surgery. There are no guidelines specific for pediatric DSC patients to prevent this costly complication. The hypothesis was that the modifications to a bundled approach for DSC patients would decrease the SWI rate. For this prospective cohort study, DSC patients were postoperatively admitted to a pediatric cardiac care unit from February 2017 to January 2018. Using a modified protocol for prevention of SWI, the infection rates pre- and post-modified protocol were compared. The primary outcome measure was SWI. Secondary outcome measures were compliance with modifications. Retrospective review of cases in pre-protocol modification era from January 1, 2014 to December 31, 2016 showed 377 pediatric cardiopulmonary bypass cases and 39 (10.4%) underwent DSC. During the post-protocol modification era, there were 129 cardiopulmonary bypass cases and 17 (13%) DSC cases. The SWI rate in DSC were 7.7% and 0% for pre-intervention and post-intervention, respectively (p = 0.52). The Bayesian confidence interval with Jeffreys prior gives a 95% confidence interval of 1.5% to 18.3% for pre-intervention and 0 to 13.5% for post-intervention. Compliance with the protocol bundle during the post protocol era was 93-100%. Although preliminary results are not statistically significant due to cohort size, the economic burden and increased LOS for each SWI is clinically significant. The early results of reduced infections for DSC patients using a modified bundle approach appear promising. Continued study and a multicenter project would be beneficial.

Isolated Chylopericardium in an Infant With Hypoplastic Left Heart Syndrome.

Isolated chylopericardium is an exceedingly rare complication in any age group. Review of the limited published case series shows the most common cause of isolated chylopericardium to be cardiac surgery. We present a case of isolated chylopericardium after a bidirectional Glenn procedure in an infant with hypoplastic left heart syndrome. (Level of Difficulty: Intermediate.).

Response of Chloris truncata to moisture stress, elevated carbon dioxide and herbicide application.

Herbicide resistance has been observed in Chloris truncata, an Australian native C4 grass and a summer-fallow weed, which is common in no-till agriculture situations where herbicides are involved in crop management. To investigate the role of drought and increased atmospheric carbon dioxide (CO2) in determining weed growth, three trials were conducted using a 'glyphosate-resistant' and a 'glyphosate-susceptible' biotype. The first two trials tested the effect of herbicide (glyphosate) application on plant survival and growth under moisture stress and elevated CO2 respectively. A third trial investigated the effect on plant growth and reproduction under conditions of moisture stress and elevated CO2 in the absence of herbicide. In the first trial, water was withheld from half of the plants prior to application of glyphosate to all plants, and in the second trial plants were grown in either ambient (450 ppm) or elevated CO2 levels (750 ppm) prior to, and following, herbicide application. In both biotypes, herbicide effectiveness was reduced when plants were subjected to moisture stress or if grown in elevated CO2. Plant productivity, as measured by dry biomass per plant, was reduced with moisture stress, but increased with elevated CO2. In the third trial, growth rate, biomass and seed production were higher in the susceptible biotype compared to the resistant biotype. This suggests that a superior ability to resist herbicides may come at a cost to overall plant fitness. The results indicate that control of this weed may become difficult in the future as climatic conditions change.

Evaluation of dormancy breaking methods for enhanced germination in four biotypes of Brassica tournefortii.

Brassica tournefortii is an important broadleaf weed of the winter season in the northern grain region of Australia. Knowledge of germination ecology of this weed would help in implementing effective weed control programs. A series of experiments were conducted to study the germination and dormancy behavior of four biotypes of B. tournefortii seeds, biotypes A (collected from barley crop), B (barley fence lines), C (chickpea crop), and D (chickpea fence lines), collected from the St George region of Queensland. The aim of this research was to determine the effectiveness of various methods on the seed dormancy release of B. tournefortii. Water, potassium nitrate and a soil extract did not release dormancy in B. tournefortii seeds (biotype A) at 20/10 °C in the light/dark regime. Cold stratification (5 °C) also did not improve germination. However, gibberellic acid (GA3; 100-300 mg kg-1) stimulated germination (>88%). Germination also improved when seeds were immersed in sodium hypochlorite (NaOCl; 42 g L-1) for 10 minutes and the effect was more pronounced under the complete dark environment (89% germination at a day/night temperature of 20/10 °C). The NaOCl treatment makes seeds more porous and decreases sensitivity to light. Another experiment in light/dark conducted at 25/15 °C with two biotypes (A and D) showed that, without NaOCl treatment, biotype A was more sensitive to light (29% germination) as compared to biotype D (92% germination). Our results suggest that dormancy in B. tournefortii seeds can be broken by the combination of NaOCl (10 min) and a dark environment. A day/night temperature of 25/15 °C was found best for optimum germination (>87%) for all the biotypes (A-D) when incubated in dark after treating with NaOCl. This research indicated a high degree of variability in germination responses for various biotypes of B. tournefortii seeds to various sets of conditions, which may be due to metabolic changes in response to maternal environments or genetically controlled mechanisms. Information gained from this study will be important in developing a better understanding of the dormancy behavior of B. tournefortii seeds in response to tillage systems or maternal environments that could influence the weed seed bank in the soil and therefore help in designing suitable weed management programs.