Marty Williams Lab

Sweet Corn

One of America's favorite vegetables, the U.S. dominates global production of sweet corn and its seed.  Weeds cause losses in most sweet corn fields, reducing both yield and quality.

Atrazine in sweet corn production

Atrazine is the most widely used herbicide in sweet corn; however, its utility is threatened in light of controversy over non-target effects, ongoing weed resistance, and regulatory changes.  We are exploring integrated weed management alternatives to atrazine for weed control in sweet corn.  The project is being conducted in the heart of Midwest sweet corn production, and includes collaboration with the University of Minnesota, University of Wisconsin-Madison, and the vegetable processing industry. 

Cytochrome P450 (CYP) alleles conditioning herbicide cross-sensitivity

We are working towards a more complete understanding of the molecular cause of herbicide sensitivity in sweet corn.  Several lines of evidence indicate the genetic basis of sensitivity in sweet corn to multiple P450-metabolized herbicides may be the result of a mutation of Nsf-1, a cytochrome P450 that conditions tolerance to nicosulfuron in field corn. 

Tolerance to crowding stress

Environmental stress tolerance is considered the physiological trait most strongly linked to genetic improvement in field corn, whereby modern hybrids have greater tolerance to a host of biotic stresses (competition, pathogen infection, etc.) and abiotic stresses (drought, low fertility, etc.).  Of all environmental stresses, tolerance to intense competition (corn-corn and corn-weed) has improved the most.  As a result, maximizing yield in modern production systems requires growing improved hybrids at populations that are higher than their predecessors.  This work is determining the extent to which such improvements can be made in sweet corn. 

Plant health

Root health and soil born organism load may be responsive to the legacy of field management and may subsequently impact plant-microbe interactions, plant health (disease and nutrition), and productivity.  Understanding how such interactions vary within and among modern cropping systems is important in the development of future technologies designed to reduce plant pest pressure, improve plant health and productivity, and ensure economic competitiveness.  The objective of this multi-state ARS project is to assess transgene and glyphosate effects on soil microbial communities, plant-microbe interactions, and plant health and productivity.

Edamame (Vegetable Soybean)

Vegetable soybean, also known as edamame, are special cultivars of soybean that are harvested near the R6 (‘full seed’) stage and the plump, immature seeds are consumed as a vegetable.  Currently, the U.S. imports most of the edamame consumed in the U.S., but that is changing.  One of the top constraints to edamame production in the U.S. is weed interference.

Herbicide tolerance

Pesticides registered for use on soybean are not necessarily registered for use on edamame.  In fact, only four herbicide active ingredients have a federal label for use on edamame: clethodim, linuron, s-metolachlor, and trifluralin.  Using perhaps the largest collection of edamame germplasm in the Western hemisphere, this work is to more fully understand the risks in potential crop injury from herbicides being considered for use on edamame.

Current IWM systems

Effective weed management in edamame will require systems that integrate various weed management tactics to achieve acceptable weed control.  Based on tools currently available to growers (or soon to be), we devised and are testing several weed management systems in field trials. 


Illinois is the nation's largest pumpkin producing state, accounting for >90% of the processing pumpkin production in the U.S.

Cover crops and double-cropping systems

Bioenergy feedstock production in the U.S. is on the rise, and depending on the scenario, 22 to 34 million acres of cropland would need to be converted to perennial energy crops in order to displace just 30% of the nation's petroleum consumption.  In order to increase both food and biofuel production in a sustainable manner, bioenergy feedstocks will derived from several sources.  One approach, bioenergy double-cropping systems, involve growing a winter annual bioenergy feedstock followed by a summer annual crop.  We are comparing crop productivity in different pumpkin production systems that vary in tillage, cover crop, and bioenergy double-cropping systems.