Hemoproteins are a very important class of enzymes in nature sharing the essentially same prosthetic group, heme, and are good models for exploring the relationship between protein structure and function. Three important hemoproteins, chloroperoxidase (CPO), horseradish peroxidase (HRP), and cytochrome P450cam (P450cam), have been extensively studied as archetypes for the relationship between structure and function. In this study, a series of 1D and 2D NMR experiments were successfully conducted to contribute to the structural studies of these hemoproteins. During the epoxidation of allylbenzene, CPO is converted to an inactive green species with the prosthetic heme modified by addition of the alkene plus an oxygen atom forming a five-membered chelate ring. Complete assignment of the NMR resonances of the modified porphyrin extracted and demetallated from green CPO unambiguously established the structure of this porphyrin as an NIII-alkylated product. A novel substrate binding motif of CPO was proposed from this concluded regiospecific N-alkylation structure. Soybean peroxidase (SBP) is considered as a more stable, more abundant and less expensive substitute of HRP for industrial applications. A NMR study of SBP using 1D and 2D NOE methods successfully established the active site structure of SBP and consequently fills in the blank of the SBP NMR study. All of the hyperfine shifts of the SBP-CN- complex are unambiguously assigned together with most of the prosthetic heme and all proximal His170 resonances identified. The active site structure of SBP revealed by this NMR study is in complete agreement with the recombinant SBP crystal structure and is highly similar to that of the HRP with minor differences. The NMR study of paramagnetic P450cam had been greatly restricted for a long time. A combination of 2D NMR methods was used in this study for P450cam-CN- complexes with and without camphor bound. The results lead to the first unequivocal assignments of all heme hyperfine-shifted signals, together with certain correlated diamagnetic resonances. The observed alternation of the assigned novel proximal cysteine β-CH2 resonances induced by camphor binding indicated a conformational change near the proximal side.

Soybean (Glycine max L. Merrill) is a new cash crop for north central and northwestern North Dakota producers. Soils and climate in these new soybean areas differ from those regions where the current fertilizer recommendations were based. Northcentral and northwestern North Dakota is more undulating, drier, cooler, and has differencing soils than eastern North Dakota and Minnesota. A three-year study to evaluate soybean best management practices was conducted during the 2016 to 2018 growing seasons. Each year, the study consisted of two sites and 12 treatments. By design, one site was on acidic (pH < 6) soil while the other was on alkaline (pH > 7.3) soil. Both site treatments were: untreated check, inoculated with rhizobia (B. japonicum L.), broadcast urea (55 kg ha-1), broadcast MAP (monoammonium phosphate, 11-52-0) (110 kg ha-1), in-furrow 10-34-0 (28 L ha-1), in-furrow 6-24-6 (28 L ha-1), foliar 3-18-18 (28 L ha-1) at V5 and R2 growth stages, and foliar 3-18-18 (28 L ha-1) with sulfate (1.1 kg ha-1) at V5 and R2. The acidic sites alone included two treatments of sugar beet (Beta vulgaris L.) waste lime (4.4 Mg ha-1 and 8.8 Mg ha-1). The alkaline sites alone received treatments of iron ortho-ortho-EDDHA (1.8% Fe) (7.1 L ha-1), and sodium (naked- without Fe) ortho-ortho-EDDHA (7.1 L ha-1). Treatments did not impact soybean yield, protein content or oil content at the 95% significance level. Sugar beet waste lime surface applied at planting at rates of 4.4 Mg ha-1 and 8.8 Mg ha-1 increased soil pH to a depth of 10 cm over the course of the growing season. / North Dakota Soybean Council

In the Midwest, it can be beneficial to interseed cover crops into corn (Zea mays L.) since there is a limited time for them to establish and grow after corn harvest. Research conducted in four environments in North Dakota quantified the impacts of planting method and time of planting when grown with or without corn competition on the establishment, and development of three cover crop species. Limited light intensity (less than 20%) under the corn canopy drastically reduced cover crop development. Soil water can also constrain cover crop establishment. Model simulations suggest soil water is more limiting for cover crop establishment in August compared with June or July. Interseeded cover crops had no effect on corn yield or the following soybean (Glycine max (L.) Merr.] crop due to minimal amounts of biomass produced.

Soybean is a vital cash, oil and protein crop. To achieve good yields and quality, adequate amounts of essential nutrients are required. Therefore, application of P and K plus inoculation with Bradyrhizobium bacteria should be included in the general production of soybean. However, the practice in South Africa is to apply no P and K when producing soybean since the farmers rely on residual P and K from the previous cropping season. The objective of this study was to determine that direct P and K application to a soybean crop may have positive results in terms of production and quality. The research was conducted at the Hatfield Experimental Farm of the University of Pretoria under green-house and open field conditions during the 2010/2011 season. The field trial treatments consisted of combinations of 3 levels of P (0, 20 and 40 kg P ha-1) and 3 levels of K (0, 50 and 100 kg K ha-1)applied in factorial combination for a Completely Randomized Block design, replicated four times. The pot trial was also a factorial experiment using a Completely Randomized Design with the two factors each at five levels of application (P at 0, 10, 20, 30 and 40 kg P ha-1 and K at 0, 50, 100, 150 and 200 kg K ha-1). Each treatment combination was replicated four times. Phosphorus and K were applied as Superphosphate (10.5%) and KCl (50%) respectively. The cultivar LS 6161R was planted under rain-fed conditions while LS 6162R was used as test crop in the green-house. Seeds were inoculated at planting with Bradyrhizobium japonicum, with no additional N applied during the season. Composite soil samples were collected from each plot and pot before and after planting and analyzed for pH (H2O) and plant-available nutrients. During the growing season,the field trial plants were sampled for LAI while canopy closure and plant height were measured for plants in the middle rows of each plot. Harvesting commenced after leaves senesced and pods had turned brown. The data recorded was on the number of pods per plant, number of seeds per pod, number of nodes per plant, fresh and dry root, stem and pod mass, 100-seed mass, total seed yield as well as protein and oil content. The results for the field trial showed that K significantly improved plant height, canopy closure and 100-seed mass as compared to the control. The application of P and K revealed no significant impact on leaf area index. Although not significantly, pod number per plant was reduced by applying P, resulting in the control having the highest number of pods. A significant improvement in grain yield was observed through application of K. The highest grain yield (2.60 t ha-1) was observed at the highest K level (100 kg K ha-1). The lowest grain yield was observed where no K fertilizer was applied. Although grain yield was not significantly affected by P nor the P*K interaction, there was a trend of increased yield with increased levels of P and P*K.Phosphorus, irrespective of the application rate, increased protein content but decreased oil content, while increased K application rates resulted in increased oil content while it decreased the protein content as compared to the control. The green-house data showed that plant height was significantly and positively affected by P, K as well as the P*K interaction. Maximum mean plant height were recorded with low application of P and no K (10 kg P + 0 kg K ha-1) as well as medium application of K and no P(0kg P + 100 kg K ha-1) which were significantly higher than the measurements recorded at 20, 30 and 40 kg P ha-1 regardless of K applied. In general, the range in number of nodes per plant was very narrow (19 to 21) and node number was not affected by P and K application. The lower levels of P fertilizer (10 and 20 kg P ha-1) gave the greatest number of pods. P*K interaction effects were not significant. With two exceptions, plants receiving 40 kg P ha-1 regardless of K tended to have the highest number of nodules. Although there was no statistical significance recorded between the treatments, 30 kg P + 150 kg K ha-1 produced the highest root fresh mass which is higher than that of the control plants but on par with plants receiving 10kg P + 100 kg K ha-1. The data on dry root mass of soybean had shown that various rates of P had a negative effect on it. There was a gradual decrease in pod mass with increased application of P from 10 to 40 kg P ha-1with the latter having the lowest pod mass than even that of the control. Although K and P*K interaction were not significant, all K application rates resulted in increased fresh and dry stem mass. From the current study, medium to high levels (± 100-150 kg K ha-1) of K applied directly to the soybean crop can be recommended as it had a positive impact on soybean growth and yield. On the other hand, the plant’s reaction to P was very much dependent on the initial soil P level, resulting in varying reactions. Therefore the farmer’s practice of using residual P from the previous season could not be proven completely wrong. / Dissertation (MSc Agric)--University of Pretoria, 2013. / gm2014 / Plant Production and Soil Science / unrestricted

Onarm research was conducted in 2011 and 2012 to determine the postemergence and residual control by dicamba of glyphosate-resistant (GR) Palmer amaranth (Amaranthus palmeri S. Wats.). Preemergence dicamba at 0, 0.28, 0.56, and 1.1 kg ae ha-1 and 0.07 kg ae ha-1 flumioxazin was applied at 30, 15 and 0 days prior to planting. Postemergence dicamba at 0.28, 0.56, and 1.1 kg ae ha-1 with and without 0.84 kg ae ha-1 glyphosate was applied to 5, 10 and 15 cm Palmer amaranth. In addition, a greenhouse experiment was conducted in 2012 to evaluate and confirm the optimum rate for control of Palmer amaranth with a new formulation of dicamba (BAS 18322H). In the greenhouse, dicamba at 0.14, 0.28, 0.56, 1.1, and 2.2 kg ae ha-1 was applied to 5, 10, and 15 cm Palmer amaranth.

A large portion of irrigated soybean in Mississippi are planted on raised beds spaced 96.52 cm apart. There is recent interest in growing soybean in narrower rows. Previous research indicates that narrower row spacing can provide advantages over wider arrangements, including increased light interception, improved weed management and greater seed yield. Soybean was planted in 96.52 cm single rows, 96.52 cm twin rows and 50 cm rows on wide beds (200 cm) at three seeding rates. Canopy closure was monitored throughout the growing season. Soybean planted in narrow rows had consistently faster canopy closure than single rows at all site years. Similarly, there was a 10% to 13% seed yield advantage for the narrow row spacing over the single row spacing at each site year. With the introduction of novel technology, such as the twin row planter, comes equipment malfunction and/or misuse that could reduce seed yield. Producer decisions in the event of a planting/planter error can be challenging. The economic loss due to a planter error may vary by soil type due to differences in plant development. The purpose of this research is to determine the agronomic effects associated with multiple potential twin row planter errors on two distinct soil types across multiple maturity groups commonly found in Mississippi. Canopy closure of each planting error was monitored throughout the growing season. Seed yield was reduced by 9 to 18% when a whole twin row was missing compared to the untreated check at all site years.

Threecornered alfalfa hopper, Spissistilus festinus (Say), is a pest of soybean during vegetative and reproductive stages. The primary damage from this pest is girdling of the main stem during vegetative stages and girdling of the petioles during reproductive stages. Previous research determined that yield losses are greater during reproductive stages than vegetative stages. I hypothesized that some reproductive stages are more vulnerable to damage than other stages. I used field cages infested with different pest densities at five reproductive stages of group IV soybean. A greenhouse study compared the injury and damage caused by the adults and nymphs. The field study showed that the threecornered alfalfa hopper did not significantly impact yields at the growth stages studied. Adults preferred to feed on leaf petioles while nymphs fed mostly on stems. Significant yield reduction was noticed at growth stage R4 in the greenhouse due to adult and nymphs compared to control.

Soybean is an economically important crop. It is a selfertilized species grown on vast contiguous acres. These facts predispose soybean to disease epidemics. Cercospora sojina, causal agent of frogeye leaf spot, has reduced United States soybean productivity 0.3 percent on average per year between 2008 and 2010. Several states have reported the pathogen developing resistance to the strobilurin class of fungicides. To date genetic host resistance has been identified as single dominant genes (Rcs1, Rcs2, and Rcs3). However, the lifespans of Rcs1 and Rcs2 were 10 and 16 years respectively. Currently, the Rcs3 locus has been utilized in all major soybean breeding programs of the US and has been for over 20 years. Seventyive accessions of soybean were found to exhibit resistance to multiple races of C. sojina while not exhibiting the Rcs3 haplotype. Twenty of these plant introductions (PIs) were screened by six races within the new race classification system of C. sojina representing all domestic variability of the pathogen. Two agronomically favorable PIs, PI398993 and PI399068, were found in this research to exhibit broad resistance to sources documented to contain most domestic variability of the pathogen. Two segregating populations were developed by crossing PI398993 x ‘Blackhawk’ and PI399068 x Blackhawk. Segregation ratios of F2 as well as F2:3 family seedling screens of both populations indicating single dominant gene action in both resistance sources. Single marker analysis indicated markers associated with the phenotype were indeed on chromosome 16 (MLG J), but possibly beyond Rcs3 in both sources. Interval mapping placed the highest probability of the resistance loci near SNP_171 and SNP_368, 72.86 and 72.48 cM respectively, but distal to the Rcs3 locus. Analysis of reaction ratings also indicated significant influence on phenotype was also associated with markers located at or beyond the published Rcs3 locus. The evidence in this research supports the hypothesis that both PIs may contain a resistance loci, potentially different than Davis, but within the same gene cluster. Equally as likely, the resistance could prove allelic to Davis.

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