Peanuts (<i>A. hypogaea</i>) are an economically important crop, a source of food allergies and a member of the South American genus <i>Arachis</i>. The eighty species of genus <i>Arachis</i> have been divided into nine sections. The largest, section <i>Arachis</i>, has been further subdivided into three genome groups. The current intuitive understanding of the evolutionary relationships among <i>Arachis</i> is based on morphological, geographic and cytogenetic data, but a comprehensive phylogenetic study for the genus is lacking. A total of 48 species representing all nine sections were used to reconstruct a phylogeny based on sequence information from plastid <i>trn</i>T-<i>trn</i>F and nuclear ITS genomic regions. Phylogenetic analysis resolved section <i>Extranervosae</i> at the base, followed by sections <i>Triseminatae</i> and <i>Caulorrhizae</i>. Two major terminal lineages were recovered. One is comprised of sections <i>Erectoides</i>, <i>Heteranthae</i>, <i>Procumbentes</i>, Rhizomatosae</i>, and <i>Trierectoides</i>, referred to here as group erectoides. The other is comprised of two major clades, arachis I (B genome, D genome, and aneuploid species) and arachis II (A genome species). The phylogenetic trees show that sequence data partially agrees with the relationships described in the monograph; however, some further investigation is necessary to clarify relationships within and among species of the two terminal lineages. In addition, the major allergen Ara h 2 from 12 wild species from across the genus was analyzed for mutations that could potentially produce a hypoallergenic ortholog. It was found that the evolution of the allergen mostly reflected the species phylogenies based on ITS and combined. The majority of substitutions and length variations were concentrated in the loop connecting helices H2 and H3. Section <i>Arachis</i> species tended to have larger H2-H3 loops, while those from other sections had shorter loops. The immunodominant epitopes #6 and #7, located within this loop, tended to contain mutations or were truncated among species outside of section <i>Arachis</i>. Dot immunoblots showed reduced IgE-binding to peptides representing portions of the H2-H3 loop from <i>A. guarantica</i> and <i>A. triseminata</i>. Orthologs from wild species have demonstrated that they could potentially contain variations of the allergen Ara h 2 that could be utilized to develop a safer peanut cultivar. / Ph. D.

The passage of the 2002 Farm Bill and the removal of the peanut quota system revealed underlying fundamental problems in the Virginia peanut industry. Lower yields and high costs plague producers at the farm level, acreage levels continue to decline and it is doubtful that peanut production in Virginia will continue at levels seen in the past. The structured market due to the quota system has provided little incentive in the past for technological investment. Investment in technology such as high oleic peanuts and capturing value at the consumer level are seen as ways to improve the situation in Virginia. In particular increased coordination at all levels of the supply chain would be needed to ensure that the consumer is brought a product with characteristics they desire. The literature provides ample information regarding the formation of alliances and coordination in general. According to Cozzarin and Barry (1998), vertical integration, similar to vertical alliances are set up for the following reasons: mitigating transactions costs, taking advantage of output or input price differentials of a competitor, and reducing uncertainties in costs and/or prices. Cozzarin and Barry (1998) also note that there is an increasing move toward vertical coordination in many agriculture sectors, the reasons cited for the current trend include: a) the growing influence of consumers in controlling the agri-food agenda; b) the increasing marketing power of large food companies; and (c) technological changes that necessitate coordination. Of these three reasons, the peanut industry falls under the first two. Vertical coordination is seen to be a solution when two or more entities are able to accomplish more efficiently their objectives than they are able to on their own. For the peanut industry, the agency theory and in particular principal-agent theory is the most applicable to the peanut industry. A linear model is used to examine the effects of increased coordination along the supply chain. The linear model also provides a snapshot of how decisions made at the farm level reverberate through the entire supply chain. The linear model includes the comparison of increased profits due to premiums at the consumer level. Results of the linear model indicate that the Virginia peanut industry will have difficulty maintaining current production levels without investment in the sector, without changing the way the supply chain operates. Principal-agent theory and specifically the work done on contracts in the pork and poultry industries provide a framework within which the peanut industry could avoid asymmetric information and moral hazard. This study attempts to identify underlying problems along with possible solutions or the Virginia peanut industry. / Master of Science

Allergies have the potential to be a life-long debilitating fight, especially the severe reactions from allergies such as anaphylaxis. Peanut allergies tend to be both common and severe, and they happen to be found hiding in many food products. People can have allergic reactions to food products that were made in the same facility as peanut products, that is why it is so important to be aware of the products that are being consumed. The incidence of peanut allergies has increased in the last decade, which is why it is crucial to study these allergies. This thesis looks at when the best time is to introduce peanut products to young children and the common risk factors that are associated with peanut allergies in children. The risk factors that are being looked at include: genetics, socioeconomic status, and ethnicity. This thesis also investigates a couple of treatment options for if your child develops a peanut allergy.

Peanut, Arachis hypogaea (L.), provides good rotational benefits for subsequent crops. During 2017, 2018, and 2019, research was conducted to determine the defoliating caterpillar complex in peanut in Mississippi, create a sweep net threshold for the complex, and determine yield losses associated with defoliation. The complex is comprised of yellow-striped armyworm, Spodoptera ornithogalli (Guenée); soybean looper, Chrysodeixis includens (Walker); corn earworm, Helicoverpa zea (Boddie); fall armyworm, S. frugiperda (Coquillet); southern armyworm, S. eridania (Stoll); beet armyworm, S. exigua (Hübner); green cloverworm, Hypena scabra (Fabricius); velvetbean caterpillar, Anticarsia gemmatalis (Hübner); and granulate cutworm, Feltia subterranea (F.). There was a significant relationship between the number of caterpillars on a drop cloth and the number per 25 sweeps. Defoliation during vegetative and early reproductive stage peanut caused a delay in canopy closure for all levels of defoliation although yield losses of 11.2% only occurred when defoliation reached 100%. During late season, peanut yield was reduced by 13% when defoliation reached 50%. With these data, a sweep net sampling and defoliation threshold can be derived. Managing caterpillar pests all season is necessary to reduce chances of yield loss due to defoliation.

Studies were conducted in the field from 2018-2019 in peanut to optimize weed control through application methods and herbicide choices. The herbicide studies were established in Mississippi, Oklahoma, Florida, and Alabama. Across trials, programs that included imazapic POST improved weed control at 28 days after treatment (DAT). The most effective PRE herbicides were flumioxazin, diclosulam, and S-metolachlor, while the use of pendimethalin was less effective. Various nozzles and operating pressures were evaluated for weed control in peanut. Droplet size was measured for each of the nozzles used at all operating pressures tested to determine classification. Classification was determined using the ASABE S572.2 standard. There was no effect on weed control or yield based on nozzle type or application pressure.

Background: Despite the clinical severity and rising prevalence of peanut allergy, there is a marked absence of widespread, practical treatments available for peanut-allergic patients. Peptide immunotherapy, a disease-modifying treatment that uses short peptides recognized by T cells, has been shown to reduce allergic symptoms of allergic rhinoconjunctivitis. This project investigated the ability of peptides from the major peanut allergen Ara h 1 to protect against peanut-induced anaphylaxis and induce immunomodulatory changes in a mouse model. Methods: Mice transgenic for the human leukocyte antigen DRB1*0401 were sensitized to peanut epicutaneously and treated with two intraperitoneal injections of peptides from Ara h 1. Mice were then challenged with intraperitoneal whole peanut and observed for signs of anaphylaxis. Flow cytometry was used to isolate peanut-specific CD4+ T cells labelled with Ara h 1 peptide-loaded tetramers and additional Th1, Th2, and regulatory markers. Results: Peptide-treated mice were protected from severe peanut-induced anaphylaxis. Control mice treated with a sham peptide experienced a mean maximum temperature drop of 3.2°C, while mice treated with Ara h 1 peptides experienced a drop of 1.6°C (p=0.067 vs control). Maximum clinical score was 2.5 in control mice, and 1.4 in treated mice (p=0.0097). Mean hematocrit for control mice was 52.5%, and 47% for treated mice (p=0.013). PD-1+CD4+ T cells were significantly increased in the mesenteric lymph nodes (p = 2.28e-0.05) and spleens (p = 0.014) of peptide-treated mice. MIP1-a+CD4+ T cells were significantly decreased in the peritoneal lavage (p = 0.008). Conclusion: Ara h 1 peptide immunotherapy protected against severe peanut-induced anaphylaxis in a mouse model. Peptide-treated mice experienced significantly reduced drops in core body temperature, clinical signs of allergic reaction, and hemoconcentration. Clinical protection was associated with decreased expression of the pro-inflammatory chemokine macrophage 1-a and increased expression of the surface marker programmed cell death protein 1. / Thesis / Doctor of Philosophy (PhD) / Peanut allergy is a growing public health concern. Its prevalence has doubled in the past 10 years and currently stands at 2%. Reactions to peanut account for the majority of food-induced fatal allergic reactions, termed anaphylaxis. Currently, there are no treatments available for patients with peanut allergy. Healthcare workers can only offer peanut-allergic patients advice on peanut avoidance and rescue medications in case of accidental ingestion. This research project investigated the ability of a new treatment called peptide immunotherapy to prevent severe allergic reactions to peanut in a mouse model of peanut allergy. Peptide treatment uses small portions of the peanut allergen to shift the immune response from pro-inflammatory to anti-inflammatory. After peptide treatment, peanut-allergic mice were protected from severe allergic reactions in response to peanut and their immune cells produced lower levels of pro- inflammatory molecules.

Consumers view natural antioxidants as a safe means to reduce spoilage in foods. In addition, these compounds have been reported to be responsible for human health benefits. Identification of these compounds in peanut skins may enhance consumer interest, improve sales, and increase the value of peanuts. This study evaluated analytical methods which have not been previously incorporated for the analysis of peanut skins. Toyopearl size-exclusion chromatography (SEC) was used for separating phenolic size-classes in raw methanolic extract from skins of Gregory peanuts. This allowed for an enhanced analysis of phenolic content and antioxidant activity based on compound classes, and provided a viable preparatory separation technique for further identification. Toyopearl SEC of raw methanolic peanut skin extract produced nine fractions based on molecular size. Analysis of total phenolics in these fractions indicated Gregory peanut skins contain high concentrations of phenolic compounds. Further studies revealed the fractions contained compounds which exhibited antioxidant activities that were significantly higher than that of butylated hydroxyanisole (BHA), a common synthetic antioxidant used in the food industry. This indicates peanut skin extracts are a viable antioxidant source, and that synthetic antioxidants can be replaced with those naturally-derived from peanut by-products. Structures contained in each fraction were identified using high performance liquid chromatography (HPLC) coupled with electrospray ionization (ESI) ion trap mass spectrometry (MSn). Prior to this study, approximately 20 compounds have been identified in peanut skins. The combination of Toyopearl SEC with ESI-HPLC-MSn allowed for the identification of 314 phenolic-based compounds, most of which are newly discovered compounds in peanut skins. Many compounds identified are known to have powerful antioxidant effects, and also have been reported to exhibit numerous beneficial chemical and biological activities, including the treatment of various human health-related conditions. It is evident that peanut skins may be a potential untapped source for the extraction of natural food antioxidants, nutracueticals, and even pharmaceuticals. Because peanut skins are largely a wasted resource to peanut processors, the novel polyphenols identified in this research could have a significant financial impact on the peanut industry. / Ph. D.

Master of Science

Since Senegal's independence in 1960, groundnuts (peanuts) have been the dominant agricultural export crop. Currently, groundnut output levels are on the decline and no clear reason for the downward trend has been found. Privatization efforts are underway as the government explores ways to breathe some life into the ailing sector, particularly as it relates to groundnut production. The 50 percent currency devaluation of 1994 constituted a major exogenous shock to the sector. Much research has been done about the macro-level impact of the changes that are taking place. However, little work has been done recently (i.e. since the devaluation) at the micro-level. This work addressed this lack by studying the micro-level dynamics of groundnut production. Elasticities were generated and used in the analysis of policy impacts on production. The own-price elasticity of supply groundnut indicated that supply response should be positive following an increase in producer price. The increase in producer prices following the devaluation did not occasion the expected supply response. Possible reasons for this failure were explored. It is hoped that the information revealed will complement the store of information on production in the Groundnut Basin that is already available. Thus, the present work will prove useful to public and private researchers and policy makers seeking to increase their understanding of the sector. / Master of Science

Call number: LD2668 .T4 1984 N39 / Master of Science