Papers by Marie Jasieniuk
File containing genotype data from 12 microsatellite (SSR) loci for 412 individuals from 14 Loliu... more File containing genotype data from 12 microsatellite (SSR) loci for 412 individuals from 14 Lolium perenne ssp. multiflorum populations from California in genepop file format for easy conversion to other file formats
File containing genotype data from 12 microsatellite (SSR) loci for 412 individuals from 14 Loliu... more File containing genotype data from 12 microsatellite (SSR) loci for 412 individuals from 14 Lolium perenne ssp. multiflorum populations from California formatted for analysis with STRUCTURE software
File containing genotype data from 12 microsatellite (SSR) loci for 412 individuals from 14 Loliu... more File containing genotype data from 12 microsatellite (SSR) loci for 412 individuals from 14 Lolium perenne ssp. multiflorum populations from California formatted for analysis with Genalex package in Excel software
Journal of The Torrey Botanical Society, Oct 1, 2012
ABSTRACT Prolific production of offspring is generally characteristic of invasive plant species. ... more ABSTRACT Prolific production of offspring is generally characteristic of invasive plant species. However, Allee effects and other populationlevel processes may constrain reproductive success. This study identified variation in seed quality resulting from different genetic diversity levels in parental populations of an invasive grass. Using the outcrossing and wind-pollinated annual grass Lolium multiflorum, experimental populations were created with independently varying size and genetic diversity. Seeds from parental populations with lower diversity germinated and emerged from the soil at significantly lower rates than seeds from populations with the highest diversity. This effect was not detected in later-occurring fitness components such as flower production per planted seed. Reductions in seed germination and seedling numbers can affect future generations by reducing the size and/or genetic diversity of the resulting populations. The reduced offspring quality seen here suggests that fecundity and invasiveness vary not only among invasive species or potential invasive species, but also among populations of the same invasive species and highlights an advantage of genetic diversity within invasions.
Canadian Journal of Plant Science, 1993
Seven populations of Xanthium strumarium L. collected from wetlands and arable fields were examin... more Seven populations of Xanthium strumarium L. collected from wetlands and arable fields were examined for their responses to three levels of bentazon application. Significant differences were observed among populations for all traits measured. Contrasts between the wetland and arable populations indicated significant differences in some traits, especially the length and width of the fifth internode. These measurements are closely related to plant biomass, and they were reduced greatly in the wetland populations after bentazon treatment. However, an overall comparison using canonical discriminant analysis failed to show differences between the wetland and arable populations, suggesting that differences in response to herbicide between the two ecotypes may be due to changes in a few traits relating to fitness. Key words: Growth, weed, herbicide, bentazon, cocklebur, Xanthium strumarium
Weed Research, Aug 1, 2009
The origins of invasive weed populations can involve multiple species, introductions and genotype... more The origins of invasive weed populations can involve multiple species, introductions and genotypes. In California, USA, self-incompatible (SI) Lolium species are highly successful agricultural weeds. During the last decade, resistance to glyphosate has evolved in California populations of Lolium. However, the species identity of glyphosate-resistant populations is unclear. Occurrence of three SI species, L. multiflorum, L. rigidum and L. perenne, and the lack of reproductive barriers between them, suggests that any or all species may be contributing to resistant populations. To elucidate the identity and evolutionary history of resistant Lolium, we assessed genetic variation of known species and unknown California individuals using five simple sequence repeat loci, a nuclear DNA sequence and a chloroplast DNA sequence. Employing two analytical approaches, we identified three major genetic groups within the accessions of SI species that were similar, but not identical, to the taxonomic species identities. California glyphosate-resistant and susceptible plants were most closely related to the L. multiflorum group. However, a few glyphosate-resistant plants and a third of the glyphosate-susceptible plants also identified with L. rigidum and L. perenne. While L. rigidum and L. perenne contribute to invasive populations within California, the majority of glyphosate-resistant individuals tested were L. multiflorum.
Weed Science, Jun 1, 2014
Inheritance of glyphosate resistance was investigated in hairy fleabane populations from Californ... more Inheritance of glyphosate resistance was investigated in hairy fleabane populations from California as part of providing the information needed to predict and manage resistance and to gain insight into resistance mechanism (or mechanisms) present in the populations. Three glyphosate-resistant individuals grown from seed collected from distinct sites near Fresno, CA, were crossed to individuals from the same susceptible population to create reciprocal F1populations. A single individual from each of the F1populations was used to create a backcross population with a susceptible maternal parent, and an F2population. Based on dose response analyses, reciprocal F1populations were not statistically different from each other, more similar to the resistant parent, and statistically different from the susceptible parent, consistent with nuclear control of the trait and dominance to incomplete dominance of resistance over susceptibility in all three crosses. Glyphosate resistance in two of the three crosses segregated in the backcross and the F2populations as a single-locus trait. In the remaining cross, the resistant parent had approximately half the resistance level as the other two resistant parents, and the segregation of glyphosate resistance in backcross and F2populations conformed to a two-locus model with resistance alleles acting additively and at least two copies of the allele required for expression of resistance. This two-locus model of the segregation of glyphosate resistance has not been reported previously. Variation in the pattern of inheritance and the level of resistance indicate that multiple resistance mechanisms may be present in hairy fleabane populations in California.
Scientific Reports, Feb 18, 2019
Determining the genotype of large numbers of individuals at often very large numbers of loci has ... more Determining the genotype of large numbers of individuals at often very large numbers of loci has become a common endeavor for graduate students, postdocs, technicians and (occasionally) professors. Throughput and data quality often seem to be conflicting ...
Weed Science, Mar 1, 2010
Basic factors contributing to the rapid evolution and broad distribution of acetolactate synthase... more Basic factors contributing to the rapid evolution and broad distribution of acetolactate synthase (ALS)-inhibiting herbicide resistance in smallflower umbrella sedge L. have not yet been investigated. The objectives of this study were to examine patterns of cross-resistance to ALS herbicides and genetic diversity within and among smallflower umbrella sedge populations in California rice fields to provide insight into the processes contributing to resistance spread. Twelve different patterns of herbicide cross-resistance were found across the 56 populations sampled. The frequency of populations with at least one resistant individual in the North, Central and South Sacramento Valley, and the San Joaquin Valley were 76, 86, 67, and 50%, respectively. Analysis of the genetic diversity of 29 populations using 73 sequence-related amplified polymorphism molecular markers revealed little genetic diversity within populations, with estimates of Nei's gene diversity index,h, ranging from 0 to 0.049, and Shannon's information index (I) ranging from 0 to 0.079. Hierarchical analyses of molecular variance indicated that the majority of genetic variation was partitioned among populations, rather than within populations or among regional groups. No isolation by distance was evident. Unweighted pair group method with arithmetic averages analysis indicated that population clustering was not region specific. The results suggest that resistance to ALS-inhibiting herbicides in smallflower umbrella sedge populations from California rice fields appears to have evolved independently multiple times rather than spread from a single population where resistance originated. Consequently, prevention and management of smallflower umbrella sedge in California rice fields should emphasize in-field strategies that focus on decreasing the selection pressure caused by ALS-inhibiting herbicides.
Weed Science, Dec 1, 2009
Recent advances in molecular methods and statistical analyses provide weed scientists with powerf... more Recent advances in molecular methods and statistical analyses provide weed scientists with powerful tools for examining the genetic structure of weedy plant populations. The value of these studies depends on effective sampling protocols; however, there is little consensus on how to sample plant populations for genetic diversity analyses. In this review, we draw on published literature that incorporates sampling theory and spatial statistics in population genetic analyses to identify key factors to consider when designing a sampling strategy. We discuss how sampling design is affected by research objectives, biology of the study species, population structure, marker choice, and the genetic parameters to be investigated, and we offer suggestions on defining sampling units and developing sampling protocols.
Weed Science, Mar 1, 1994
In F2progeny, derived from F1hybrids, shoot growth of seedlings, measured 4 d after germination, ... more In F2progeny, derived from F1hybrids, shoot growth of seedlings, measured 4 d after germination, distinguished susceptible (S) and resistant (R) phenotypes. Chisquare values indicated that the F2data fit a 3:1 (S:R) ratio for both populations and all trifluralin concentrations in which S and R phenotypes could be differentiated. Results indicate that trifluralin resistance in these green foxtail populations is controlled by a single, nuclear recessive gene. This study is the first to demonstrate recessive gene control of herbicide resistance in a weed species. The highly selfed nature and prolific seed production of green foxtail may have facilitated evolution of the recessive trait.
Weed Science, Dec 14, 2017
Reduced control of Italian ryegrass in California with herbicides has raised concerns about the e... more Reduced control of Italian ryegrass in California with herbicides has raised concerns about the evolution of populations with resistance to multiple herbicides. The goal of this study was to investigate variation among populations in plant response and resistance to glyphosate and glufosinate in Italian ryegrass from vineyards and orchards in northwest California. Population resistance screening using field-collected seed revealed up to 56.9% of individuals surviving glyphosate treatment at 1,678 g ae ha−1, and 53.5% of individuals surviving glufosinate treatment at 2,242 g ai ha−1in the same population. Frequencies of surviving plants within populations varied among screening times, particularly for glufosinate. Treating vegetatively propagated, genetically identical tillers with each herbicide pointed to separate mechanisms of resistance rather than cross-resistance to glyphosate and glufosinate. Dose–response experiments were conducted for each herbicide at two different screening times using a subset of populations, field-collected seed, and 10 herbicide rates. Plant survival and biomass were evaluated for each population at 3 wk after treatment and for plant regrowth 1 wk thereafter. Log-logistic regression models fit to the data were used to estimate LD50, GR50, and RD50values and calculate resistance indices (R/S ratios). Based on LD50values, the most highly resistant population was 14.4- to 19.2-fold more resistant to glyphosate than the most susceptible population tested but only 1.6- to 2.0-fold more resistant to glufosinate than the most susceptible population tested. Levels of resistance to both herbicides varied with screening time period and variable measured. Results indicate high frequencies of glyphosate-resistant plants but an early stage in the evolution of glufosinate resistance in some Italian ryegrass populations of northwest California.
Weed Research, Feb 1, 1994
Responses of 10 natural or agricultural populations of Xanthium strumarium to sublethal rates of ... more Responses of 10 natural or agricultural populations of Xanthium strumarium to sublethal rates of bentazone applied post-emergence were examined under field conditions. Both vegetative growth and reproduction of sprayed plants were affected by the herbicide. Some populations were more tolerant of bentazone than the others, but the degree of herbicide tolerance did not depend on the previous herbicide experience of a population. Bentazone treatment significantly reduced the weight per fruit in some populations, which in turn could affect the survival and growth of the subsequent seedlings. La reponse depopulations de Xanthium strumarium a des doses subletales de bentazone Nous avons etudie au champ la reponse de dix populations naturelles ou agricoles de Xanthium strumarium ^ des doses subletales de bentazone appliquee en post-levee. L'herbicide affectait la croissance et la reproduction des plantes traitees. Quelques populations etaient plus tolerantes a la bentazone que d'autres, mais le degre de tPresent address: Agriculture Canada. Research Station, Harrow. Ontario. Canada NOR IGO. tolerance ne dependait pas de I'exposition prealable des populations a l'herbicide. La bentazone reduisait significativement le poids des fruits dans quelques populations, ce qui pouvait affecter ensuite la survie et la croissance des jeunes plantes qui en etaient issues, Wirkung subletaler Dosen von Bentazon auf Xanthium strumarium Zehn Herklinfte von Xanthium strumarium wurden im Nachauflauf mit subletalen Dosen von Bentazon unter Feldbedingungen behandelt, Sowohl das vegetative Wachstum als auch die Samenbildungderbehandelten Pflanzen wurden durch das Herbizid beeintrachtigt. Einige Herkunfte waren weniger empfindlich, doch der Grad der Herbizidempfindlichkeit stand nicht im Einklang mit frliheren Erfahrungen uber die Wirkung des Herbizids. Durch die Bentazon-Behandlungen nahm das Gewicht der Samen bei einigen Herkunften signifikant ab, so daB ihre Lebensfahigkeit und das Wachstum der Keimpflanzen beeintrachtigt sein konnten.
Weed Research, Feb 1, 2009
ABSTRACT Cyperus difformis (smallflower umbrella sedge) is an economically important weed of rice... more ABSTRACT Cyperus difformis (smallflower umbrella sedge) is an economically important weed of rice in California where its control has recently been complicated by the evolution of herbicide resistance. Knowledge of the mating system of this weed is needed to elucidate the dynamics of resistance evolution and to design mitigation strategies that delay its occurrence. The aim of this study was to estimate the outcrossing rate of C. difformis using molecular and phenotypic markers. Outcrossing rates were estimated in natural field populations using sequence-related amplified polymorphism (SRAP) molecular markers and in glasshouse and field experiments using resistance to the acetolactate synthase-inhibiting herbicide bensulfuron-methyl as a phenotypic marker. Using SRAP markers, the multilocus (tm) and average single-locus (ts) outcrossing rates varied from 0.014 to 0.025 and from 0.008 to 0.012, respectively, among natural weed populations in rice fields. Using resistance to bensulfuron-methyl as a genetic marker, the average C. difformis outcrossing rate estimated was 0.009 in the glasshouse and 0.0084 in the field. These results indicate that C. difformis is a highly self-fertilising species. Therefore, the primary mechanism by which genes for herbicide resistance can be transferred among C. difformis populations in different rice fields is probably seed dispersal. Weed management should emphasise prevention of seed production and dispersal to preclude the further spread and evolution of resistance in C. difformis.
Oecologia, Sep 28, 2012
Small populations of founding individuals or survivors of incomplete management programs often re... more Small populations of founding individuals or survivors of incomplete management programs often represent critical transitions in biological invasions. Theory predicts that population size affects reproduction and, consequently, a population's expansion, but there are few empirical tests, and fewer that account for the reduced genetic diversity that often accompanies small population size. We created experimental small populations of invasive ryegrass (Lolium multiflorum) with population size varying independently from genetic diversity. Treatment independence was achieved by cloning plants to increase population size without changing diversity. Plant fitness was measured as the proportion of florets producing a seed. We analyzed the effects of population size, genetic diversity, and their interaction using ANCOVAs, one of which accounted for variation in individual plant growth. As predicted, smaller populations produced significantly lower proportion seed set. Low genetic diversity also reduced seed set, but this was best interpreted as part of a significant interaction with population size. Specifically, the effect of population size on the proportion seed set was over five times larger for populations in the medium genetic diversity treatment than the highest diversity treatment, and 6.7 times larger for populations with the lowest level of diversity. Population size variation had biologically meaningful consequences, as the rate of seed set within the low diversity treatment increased by 80 % with increasing population size. The results indicate that both the demographics and genetics of populations can influence reproduction and invasive potential, and must be considered when assessing risk and designing management plans for invasive plants.
Weed Science, Aug 1, 2008
Italian ryegrass is a major weed problem in wheat (Triticum aestivum L.) production worldwide. Tw... more Italian ryegrass is a major weed problem in wheat (Triticum aestivum L.) production worldwide. Two separate studies were conducted in Stoneville, Mississippi to evaluate: (1) the efficacy of herbicides available to Mississippi producers for controlling glyphosate-resistant (GR) Italian ryegrass (control study), and (2) fall burndown herbicide seed suppression study. Results of the control study showed that flufenacet/metribuzin EPOST followed by (fb) pinoxaden LPOST (standard treatment) provided 93% control of GR Italian ryegrass. Some other treatments provided comparable Italian ryegrass control (92% to 97%) as the standard treatment in 2017. Italian ryegrass control in the seed suppression study was 100%, 100%, 67.5%, 97%, and 99.5% from the application of the following treatments: (1) S-metolachlor + flumioxazin + paraquat in October-November fb glyphosate + clethodim in January-February fb gramoxone as needed (weed-free check); (2) Smetolachlor + flumioxazin + paraquat in October-November; (3) field cultivator (disk) in October-November; (4) glyphosate + clethodim in January-February; and (5) field cultivator in October-November fb glyphosate + clethodim in January-February, respectively. The remaining Italian ryegrass from the application of treatments 3, 4, and 5 produced 65,700; 1008; and 9 seeds m −2 , respectively. Seed suppression study highlights the importance of 100% control that is required to manage GR Italian grass.
Weed Science, Mar 1, 1996
The importance of various factors influencing the evolution of herbicide resistance in weeds is c... more The importance of various factors influencing the evolution of herbicide resistance in weeds is critically examined using population genetic models. The factors include gene mutation, initial frequency of resistance alleles, inheritance, weed fitness in the presence and absence of herbicide, mating system, and gene flow. Where weed infestations are heavy, the probability of selecting for resistance can be high even when the rate of mutation is low. Subsequent to the occurrence of a resistant mutant, repeated treatments with herbicides having the same mode of action can lead to the rapid evolution of a predominantly resistant population. At a given herbicide selection intensity, the initial frequency of resistance alleles determines the number of generations required to reach a specific frequency of resistant plants. The initial frequency of resistance alleles has a greater influence on the evolutionary process when herbicides impose weak selection, as opposed to very strong selection. Under selection, dominant resistance alleles increase in frequency more rapidly than recessive alleles in random mating or highly outcrossing weed populations. In highly self-fertilizing species, dominant and recessive resistance alleles increase in frequency at approximately the same rate. Gene flow through pollen or seed movement from resistant weed populations can provide a source of resistance alleles in previously susceptible populations. Because rates of gene flow are generally higher than rates of mutation, the time required to reach a high level of resistance in such situations is greatly reduced. Contrary to common misconception, gene flow from a susceptible population to a population undergoing resistance evolution is unlikely to slow the evolutionary process significantly. Accurate measurements of many factors that influence resistance evolution are difficult, if not impossible, to obtain experimentally. Thus, the use of models to predict times to resistance in specific situations is markedly limited. However, with appropriate assumptions, they can be invaluable in assessing the relative effectiveness of various management practices to avoid, or delay, the occurrence of herbicide resistance in weed populations.
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Papers by Marie Jasieniuk