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Distribution Of Two Rotation-Resistant Corn Pests In Eastern Iowa And Effects Of Soybean Varieties On Biology Of Diabrotica Virgifera Virgifera, Michael Wilson Dunbar Jan 2011

Distribution Of Two Rotation-Resistant Corn Pests In Eastern Iowa And Effects Of Soybean Varieties On Biology Of Diabrotica Virgifera Virgifera, Michael Wilson Dunbar

Graduate Theses and Dissertations

The western corn rootworm Diabrotica virgifera virgifera LeConte (WCR) and the northern corn rootworm Diabrotica barberi Smith & Lawrence (NCR) are two significant insect pests of corn in North America. Both species have adapted to crop rotation in the Midwest, NCR through extended diapause and WCR by ovipositing in alternative crops. We conducted surveys during 2008 and 2009 to collect data on the presence of rotation-resistant NCR and WCR. Data were collected by placing Pherocon AM sticky traps in soybean and corn fields and by placing emergence cages in corn fields. Rotation-resistant WCR was most common in the northeastern and east-central ...


What Is The Economic Threshold Of Soybean Aphids (Hemiptera: Aphididae) In Enemy-Free Space?, Michael T. Mccarville, Charles Kanobe, Gustavo C. Macintosh, Matthew E. O'Neal Jan 2011

What Is The Economic Threshold Of Soybean Aphids (Hemiptera: Aphididae) In Enemy-Free Space?, Michael T. Mccarville, Charles Kanobe, Gustavo C. Macintosh, Matthew E. O'Neal

Entomology Publications

Soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), is a serious pest of soybean, Glycine max (L.) Merr., in the North Central United States. Current management recommendations rely on the application of insecticides based on an economic threshold (ET) of 250 aphids per plant. Natural enemies are important in slowing the increase of aphid populations and can prevent them from reaching levels that can cause economic losses. However, biological control of A. glycines is inconsistent and can be affected negatively by the intensity of agricultural activity. We measured the impact of a natural-enemy-free environment on the capacity of the current ET ...


Environmental Analyses And Candidate Gene Expression Of Ms9 Male-Sterility Locus And Computational Identification Of Candidate Genes For Male-Sterility Loci In Soybean, Christiana Wiebbecke Jan 2011

Environmental Analyses And Candidate Gene Expression Of Ms9 Male-Sterility Locus And Computational Identification Of Candidate Genes For Male-Sterility Loci In Soybean, Christiana Wiebbecke

Graduate Theses and Dissertations

Rapid growth rate of the human population is driving the increased demand for cultivated soybean [Glycine max (L.) Merrill], a major source of protein and oil in global food, feed, and biofuel production. Increasing yield at a pace faster than traditional breeding methods presently achieve has become a need and future commitment. In soybean, a self-pollinated crop, a possibility to increase yield may result from the development of hybrid cultivars. Researchers have been interested in floral development and pollination, as these factors have a direct impact on maintaining and enhancing crop yields. Soybean breeders also need to understand phenotypic differences ...


Utilization Of Near-Isogenic Lines To Identify Genes Underlying Iron-Efficiency Qtl, Gregory Allan Peiffer Jan 2011

Utilization Of Near-Isogenic Lines To Identify Genes Underlying Iron-Efficiency Qtl, Gregory Allan Peiffer

Graduate Theses and Dissertations

Nutrient deficiencies are a significant abiotic stress of soybean. Iron deficiency chlorosis is a major concern in the upper midwestern region of the United States due to the prevalence of calcareous soils. Soybean's susceptibility to iron stress results in yield losses into the hundreds of millions each year. Understanding the molecular differences between resistant and susceptible cultivars will significantly affect future yield and revenue. Through the use of near-isogenic lines (NILs), molecular markers, and gene expression we have identified the donor parent introgressions through both classical SSR mapping and a novel method of SNP clustering which can be preformed ...


Replication Protein A And Its Role In The Iron Stress Response Of Soybean, Sarah Atwood Jan 2011

Replication Protein A And Its Role In The Iron Stress Response Of Soybean, Sarah Atwood

Graduate Theses and Dissertations

Soybean (Glycine max (L.) Merr.) is the second most abundant crop in the United States, with a total crop value of nearly $39 billion in 2010. U.S. soybean exports are used as an important protein and oil source in over 80 countries. Abiotic stress, such as iron deficiency chlorosis (IDC), threatens soybean yields, which affect farmers' profits in the United States as well as nutrition of consumers all over the world. IDC occurs when iron is unavailable to soybean roots, often in the calcareous soils of the upper Midwest United States. Iron stress causes a decrease in chlorophyll production ...


Effects Of Phosphorus And Potassium Fertilization Rate And Placement Method On Soybean (Glycine Max L.) Seed Quality And Long-Term Storability, Keaton Krueger Jan 2011

Effects Of Phosphorus And Potassium Fertilization Rate And Placement Method On Soybean (Glycine Max L.) Seed Quality And Long-Term Storability, Keaton Krueger

Graduate Theses and Dissertations

The fertilization rate and placement methods of phosphorus and potassium fertilizers can positively affect soybean [Glycine max L. (Merr.)] seed composition and yield in some environments, but not in others. Soybean seed production costs and chemically-treated seed disposal costs have increased, coinciding with farmers' adoption of planting chemically-treated soybean seeds. Seeds are treated with fungicides and sometimes with insecticides to provide protection from pathogens and insects before seed emergence. These changes in production costs have renewed seed industry's interest in identifying agronomic practices that enhance soybean quality, composition, and storability. Soybean seeds do not store well and seed quality ...


Development Of Single-Seed Near-Infrared Spectroscopic Predictions Of Corn And Soybean Constituents Using Bulk Reference Values And Mean Spectra, Paul R. Armstrong, Jasper G. Tallada, Charles R. Hurburgh Jr., David F. Hildebrand, James E. Specht Jan 2011

Development Of Single-Seed Near-Infrared Spectroscopic Predictions Of Corn And Soybean Constituents Using Bulk Reference Values And Mean Spectra, Paul R. Armstrong, Jasper G. Tallada, Charles R. Hurburgh Jr., David F. Hildebrand, James E. Specht

Agricultural and Biosystems Engineering Publications

Rapid, non-destructive single-seed compositional analyses are useful for many areas of crop science, including breeding and genetics. Seeds are sometimes unique and require preservation due to small samples, which necessitates development of methods for total non-destructive measurement. Near-infrared reflectance spectroscopy (NIRS) can be used for non-destructive single-seed composition prediction, but the reference methods used to develop prediction models are usually destructive. Reference methods are costly, and extensive sets of seeds must be used to obtain prediction models for multiple constituents. In this research, single-seed NIRS prediction models were developed for common constituents of soybeans and corn using composition values from ...


Effects Of Full, Abbreviated, And No Clean-Outs On Commingled Grain During Combine Harvest, H. Mark Hanna, Darren H. Jarboe Jan 2011

Effects Of Full, Abbreviated, And No Clean-Outs On Commingled Grain During Combine Harvest, H. Mark Hanna, Darren H. Jarboe

Agricultural and Biosystems Engineering Publications

Growers of identity-preserved crops desire to keep grain separate throughout the production process. Earlier research has demonstrated that some locations in a combine such as cleaning and threshing areas harbor relatively smaller amounts of grain, but require relatively large amounts of time to clean. Omitting clean-out in some areas and flushing residual grain with new grain in the first grain tank full may lower commingled grain concentration to acceptable levels for some customers.