Browsing by Subject "Peanuts"
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Item Growth performance and carcass characteristics of growing-finishing pigs fed diets containing peanut hulls, with or without added probiotic(Texas Tech University, 2004-08) Burnham, LarkPhysiological changes occur when an animal experiences stress, these changes are reflected in a shift in the microbial ecology of the gastrointestinal tract (GIT), often to the detriment of the host. Since the early 1950's, producers have relied on the prophylactic use of sub-therapeutic levels of feed-additive antibiotics to protect young pigs, especially during the vulnerable post-weaning phase. Bacteria exposed to repeated doses of antibiotics, whether therapeutic or sub-therapeutic, may develop antibiotic resistance, scientists believe this resistance can be transferred to bacteria in or on non-target species, including humans. Antibiotics also kill bacteria that are known to be beneficial to the host. Consumer concerns about antibiotic resistance have prompted the search for viable alternatives. Two feed-additives that have shown some promise as growth promotants are low levels of dietary fiber and probiotics. Like antibiotics, these feed-additives improve growth by shifting GIT microbial populations but without harming beneficial bacteria. This dissertation is the first in-depth study that combines both low levels of a dietary fiber, peanut hulls (PH), with a probiotic (multiple stabilized enzymes or MSE). Pigs were first fed graded levels of PH (0, 5,10, 15, 20, and 25%) to ascertain the most effective levels to be included in a second experiment, which combined PH (5% and 10% for the grower and finishing phases, respectively) with MSE. Average daily gain increased 19% when 5% PH were combined with MSE in the grower phase but the improvement in gain disappeared when the level of PH was raised to 10%. A third experiment compared the growth of growing-finishing pigs fed a corn-soybean meal diet supplemented with either a popular antibiotic (Tylan 40®) or MSE. There was no difference in grower phase or overall growth performance of pigs fed diets containing either additive although pigs fed MSE grew faster and more efficiently than those fed either Tylan® or the control in the late finishing phase. There is a clear indication that probiotics may act additively, if not synergistically, with low levels of fiber and may offer a safe alternative to antibiotics.Item Improving upon the management of soilborne diseases of peanut in West Texas(2012-05) Thiessen, Lindsey; Woodward, Jason E.; Ong, Kevin; Sharma, JyotsnaPeanut (Arachis hypogaea L.) is susceptible to numerous soilborne pathogens in the High Plains of West Texas including Botrytis cinerea Pers.:Fr., Pythium spp., Rhizoctonia solani Kühn AG-4, Sclerotinia minor Jagger and Sclerotinia sclerotiorum (Lib.) de Bary, Sclerotium rolfsii Sacc., and Verticillium dahliae Kleb. Because these pathogens may cause similar symptoms in peanut fields, accurate diagnosis is important for proper management to mitigate damages and losses caused by these pathogens. Fungicides are the primary management option for this region, and current application regimes are based on models developed in the Southeastern United States. This region has an arid climate and peanut development is generally later than in other areas of the United States. These factors impact initial fungicide application timing and may affect efficacy. The objectives of this research were to i) develop a disease diagnostic guide for peanut producers of this region, ii) evaluate fungicide application timing for pod rot and iii) quantify the residual activity of fungicides used in the management of pod rot of peanut. Large plot fungicide trials were conducted in the growing seasons of 2010 and 2011 to study the effects of delaying initial applications of fungicides, azoxystrobin, mefenoxam, and flutolanil on disease development. Initial applications were made 68 or 82 days after planting (DAP) with subsequent applications using a banded spray application. In 2010, the percentage of pods affected and percent damaged kernels were reduced by early applications of mefenoxam and azoxystrobin. The flutolanil treatment in 2010 showed the greatest improvement in yield compared to the control. The 2011 trial was greatly affected by drought, and no appreciable differences were seen for any of the parameters evaluated. In 2011, a fungicide bioassay was conducted to determine the residual activity of the fungicides azoxystrobin and flutolanil + propiconazole on the foliage and pods of the peanut cultivars GA09B and McCloud. Broadcast applications of both fungicides were made three times in the growing season using a backpack sprayer system. Plants were destructively sampled prior to fungicide application and 1, 3, 5, 7, 14, 21 and 28 days after application. A detached leaflet assay was completed using Sclerotium rolfsii as a quantitative measure. Fungicides did not show significant differences between one another, with both fungicides reducing activity of S. rolfsii as compared to the non-treated control. The residual activity of azoxystrobin and flutolanil + propiconazole ranged from 7 to 28 days. Additional testing is required to obtain a more accurate determination of residual activity of these fungicides. Despite poor environmental conditions for 2011, the studies conducted show that application timing may differ from current recommendations. Further study is needed to improve current fungicide application regimes and improve the management of soilborne disease in this region.Item Site specific survey of thrips vectors of viral diseases in West Texas peanut(Texas Tech University, 2000-12) Kraemer, Gye C.West Texas peanut were sampled for Thysanoptera during the seedling, vegetative and bloom stages during the 1999 and 2000 growing seasons to determine thrips species composition, densities and distributions. Seven thrips species were identified from the two year survey in peanut. Three of the species Frankliniella occidentalis (Pergande), Frankliniella fusca (Hinds), and Thrips tabaci (Lindeman) are known vectors of tomato spotted wilt virus (TSWV), a devastating viral disease in peanut. A total of 736 F. occidentalis were collected in 1999 (80.3% of the total) and 2,541 in 2000 (82.0% of the total) indicating that they are the predominant thrips of peanut. Frankliniella fusca comprised 159 (17.9%) of the total thrips collected in 1999 and 543 (17.5%) of the total collected in 2000. Only ten T tabaci were collected in 1999 and five in 2000 indicating that it is not in high enough densities to cause epidemics in West Texas peanut. Frankliniella occidentalis was found on both sides of the Caprock Escarpment during peanut seedling, terminal, and bloom collection dates, the results of this survey indicate that if F. occidentalis were to vector TSWV to West Texas peanut; a devastating epidemic could occur. Frankliniella fusca, the known vector of TSWV in previous epidemics in Texas, posses a greater threat east of the Caprock, where they were detected in seedling peanuts in higher densities compared to west of the Caprock. There were no visual symptoms of TSWV detected from all 243 sample sites (3,557 row meter) in 1999 or 315 sites (4,788 row meter) In 2000.Item The economics of precision farming in the Texas High Plains(Texas Tech University, 2002-12) Watson, Susan ElizabethNot available.Item The effect of fatty acid profiles on peanut seed germination at low soil temperatures(Texas Tech University, 2000-05) Jungman, Brett S.An experiment was set up to determine if altering the fatty acid composition would affect the germination of the peanut seed in cooler environments. Nine breeding lines of Dr. Olin Smith (deceased) were selected based on the oleic to linoleic acid (O/L) ratio. The lines (entries) were selected to give a range of oleic to linoleic (O/L) content that was classified as low (<3), medium (3-10), and high (>10), with Tamspan 90, a low O/L line, used as a control variety in the study. Germination percentage of entries were evaluated based on the O/L ratio, as well as the unsaturated to saturated (U/S) ratio. The unsaturated to saturated ratio was calculated by dividing the sum of oleic and linoleic acids by the sum of palmitic and stearic acids. These were not isogenic lines, so there may be other genetic traits, besides the fatty acid content, that were involved with germination differences. The lines were all of the Spanish type which is well adapted to the West Texas growing area. Fatty acid composition of the seed oil was measured on each of the selected lines by forming methyl esters of the oil and analyzing them by gas chromatography. Seeds were germinated in a controlled chamber at five different temperatures: an alternating 30°C for eight hours and 20°C for sixteen hours, and constant temperatures of 20°C, 18°C, 16°C, and 14°C. Germination counts were taken at 4, 10, and 12 days based on AOSA germination procedures for Spanish variety peanuts. Germination decreased as O/L and U/S ratios increased, especially at lower (16°C and 14°C) temperatures. This trend was not solely a factor of the O/L ratio, but also appeared to be related to the U/S ratio.Item The feasibility of a peanut/sorghum intercropping system under rain-fed conditions(Texas Tech University, 1986-12) Abdi, Ali MohamedNot available