A5024105619- Weed Control and Herbicide Applications
- Plant and animal studies
- Pesticide and Herbicide Environmental Studies
- Ecology and Vegetation Dynamics Studies
- Plant tissue culture and regeneration
- Turfgrass Adaptation and Management
- Genetic diversity and population structure
- Biological Control of Invasive Species
- Agronomic Practices and Intercropping Systems
- Legume Nitrogen Fixing Symbiosis
- Plant Parasitism and Resistance
- Allelopathy and phytotoxic interactions
- Plant Taxonomy and Phylogenetics
- Botany, Ecology, and Taxonomy Studies
- Botany and Plant Ecology Studies
- Bioenergy crop production and management
- Yeasts and Rust Fungi Studies
- Plant Diversity and Evolution
- Plant Virus Research Studies
- Berry genetics and cultivation research
- Coastal wetland ecosystem dynamics
- Rangeland and Wildlife Management
- Environmental DNA in Biodiversity Studies
- Agriculture and Farm Safety
- Plant and fungal interactions
University of California, Davis
2012-2021
Planta
1993-2014
Plant (United States)
2009-2013
University of California System
2013
California State University, Fresno
2013
Oregon State University
2013
Agricultural Research Service
2013
The Huntington Library, Art Museum, and Botanical Gardens
2006
Université de Montréal
2005
Montana State University
2001
The importance of various factors influencing the evolution herbicide resistance in weeds is critically examined using population genetic models. include gene mutation, initial frequency alleles, inheritance, weed fitness presence and absence herbicide, mating system, flow. Where infestations are heavy, probability selecting for can be high even when rate mutation low. Subsequent to occurrence a resistant mutant, repeated treatments with herbicides having same mode action lead rapid...
Abstract We present an R package to help remedy the lack of software for manipulating and analysing autopolyploid allopolyploid microsatellite data. polysat can handle genotype data any ploidy, including populations mixed assumes that allele copy number is always ambiguous in partial heterozygotes. It import export eight different formats, calculate pairwise distances between individuals using a stepwise mutation infinite alleles model, estimate ploidy based on counts frequencies F ST...
Abstract Horseweed (Conyza canadensis), a member of the Compositae (Asteraceae) family, was first broadleaf weed to evolve resistance glyphosate. Horseweed, one most problematic weeds in world, is true diploid (2n = 2x 18), with smallest genome any known agricultural (335 Mb). Thus, it an appropriate candidate help us understand genetic and genomic bases weediness. We undertook draft de novo assembly horseweed by combining data from multiple sequencing platforms (454 GS-FLX, Illumina HiSeq...
Selection by herbicides has resulted in widespread evolution of herbicide resistance agricultural weeds. In California, to glyphosate was first confirmed rigid ryegrass 1998. Objectives this study were determine the current distribution and level Italian ryegrass, assess whether could be due an altered target site. Seeds sampled from 118 populations seedlings treated with at 866 g ae ha −1 . Percentage survivors ranged 5 95% 54 populations. All plants 64 died. One susceptible (S) population,...
Recent increases in glyphosate use perennial crops of California, USA, are hypothesized to have led an increase selection and evolution resistance the herbicide Conyza canadensis populations. To gain insight into evolutionary origins spread inform management strategies, we investigated geographical distribution C. across surrounding Central Valley, its spatial relationship groundwater protection areas (GWPA), genetic diversity population structure history using microsatellite markers....
Herbicides are the most commonly used means of controlling weeds. Recently, there has been growing concern over potential impacts global climate change, specifically, increasing temperatures and elevated carbon dioxide (CO2) concentrations, on sensitivity weeds to herbicides. Here, glyphosate response both Conyza canadensis Chenopodium album was evaluated under different environmental conditions. Reduced observed in species increased temperature, CO2 level, combination factors. Increased...
Abstract Comparing genetic diversity, differentiation, and performance between native nonnative populations has advanced our knowledge of contemporary evolution its ecological consequences. However, such between‐range comparisons can be complicated by high among‐population variation within ranges. For example, vs. small non‐representative subsets for species with very large distributions have the potential to mislead because they may not sufficiently account within‐range adaptation climatic...
In F 2 progeny, derived from 1 hybrids, shoot growth of seedlings, measured 4 d after germination, distinguished susceptible (S) and resistant (R) phenotypes. Chisquare values indicated that the data fit a 3:1 (S:R) ratio for both populations all trifluralin concentrations in which S R phenotypes could be differentiated. Results indicate resistance these green foxtail is controlled by single, nuclear recessive gene. This study first to demonstrate gene control herbicide weed species. The...
Numerous factors, including mutation, selection, inheritance, mating System, and gene flow are important in the evolution of herbicide resistance weeds. Spontaneous mutation is believed to be main source genetic variation for a geographic region which has not been detected previously. Despite frequencies that probably very low, probability occurrence at least single resistant mutant susceptible population may high weed species with fecundities large sizes. Subsequent repeated treatments...
Resistance to ALS-inhibiting herbicides in Cyperus difformis has evolved rapidly many rice areas worldwide. This study identified the mechanism of resistance, assessed cross-resistance patterns all five chemical groups four C. biotypes, and attempted sequence ALS gene. Whole-plant enzyme activity dose-response assays indicated that WA biotype was resistant evaluated. The IR bensulfuron-methyl, orthosulfamuron, imazethapyr, propoxycarbazone-sodium less bispyribac-sodium halosulfuron-methyl,...
Management of agroecosystems with herbicides imposes strong selection pressures on weedy plants leading to the evolution resistance against those herbicides. Resistance glyphosate in populations
Two broad aims drive weed science research: improved management and understanding of biology ecology. In recent years, agricultural research addressing these two has effectively split into separate subdisciplines despite repeated calls for greater integration. Although some excellent work is being done, developed a very high level repetitiveness, preponderance purely descriptive studies, failed to clearly articulate novel hypotheses linked established bodies ecological evolutionary theory....
The inheritance of resistance to dicamba in wild mustard was determined by making reciprocal crosses between a resistant (R) population derived from field treated repeatedly with auxin-type herbicides, and known susceptible (S) population. resulting F 1 hybrids were selfed produce 2 populations backcrossed the S parent. At three- four-leaf stage, parental, , backcross screened for at three dosages (50, 200, 400 g ai ha −1 ). progeny survived all exhibited levels injury similar R parental...
Crop yield loss–weed density relationships critically influence calculation of economic thresholds and the resulting management recommendations made by a bioeconomic model. To examine site-to-site year-to-year variation in winter Triticum aestivum L. (winter wheat)– Aegilops cylindrica Host. (jointed goatgrass) interference relationships, rectangular hyperbolic loss function was fit to data sets from multiyear field experiments conducted at Colorado, Idaho, Kansas, Montana, Nebraska, Utah,...
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 these studies depends on effective sampling protocols; however, there is little consensus how to sample populations diversity analyses. In this review, we draw published literature that incorporates theory spatial statistics population identify key factors consider when designing a strategy. We discuss design...
Summary Glyphosate‐resistant weeds are an increasing problem in perennial cropping systems the Central Valley of California, USA . To elucidate evolutionary origins and spatial spread resistance, we investigated geographical distribution glyphosate resistance population genetic diversity structure Conyza bonariensis compared results with previously studied C. canadensis Thirty‐five populations from orchards vineyards across were sampled. Population was assessed using microsatellite markers....
Glyphosate, paraquat and acetyl CoA carboxylase (ACCase)-inhibiting herbicides are widely used in California annual perennial cropping systems. Recently, glyphosate, paraquat, ACCase- acetolactate synthase (ALS)-inhibitor resistance was confirmed several Italian ryegrass populations from the Central Valley of California. This research characterized possible mechanisms resistance.Multiple-resistant (MR1, MR2) resistant to at least three modes action. Dose-response experiments revealed that...
International trade in horticultural plants is a major pathway of introduction invasive species. Pampas grass (Cortaderia selloana) an species origin that native to South America but cultivated as ornamental regions with Mediterranean climates worldwide. To gain insight into the history populations California, we analysed microsatellite marker variation and C. selloana. We sampled 275 from diverse sources 698 33 four geographical California. A model-based Bayesian clustering analysis...