Browsing by Subject "Corn"
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Item Biochemistry and physiology of water stress in cotton, corn, and sorghum(Texas Tech University, 1977-05) Ackerson, Robert CharlesThe purpose of this study was to investigate the effects of water stress on specific physiological and biochemical processes in field grown cotton (Gossypium hirsutum L.), com (Zea mays L.) , and sorghum (Sorghum bicolor L. Moench)o These three crops are distinctly different witli respect to their drought tolerance. Investigation of such processes as regulation of water use, photosynthesis and specific enzyme activity were conducted in order to ascertain whether these parameters were differentially affected by water stress in the three species. Elucidating the level of water stress required to inhibit a physiological process or identifying specific factors that confer drought tolerance to one species as opposed to another, may aid in enhancing agricultural productivity particularly in many arid and semi-arid environments. Furthermore, once specific limiting factors of growth under water stress situations are identified, these data can be utilized in a comprehensive effort toward producing more drought tolerant genotypes within a crop species.Item Developing alternative markets in Veracruz : the case of totomoxtle(2012-08) Rizzo Lara, Rosario De La Luz 1985-; Torres, Rebecca MariaA series of economic and political changes that occurred in the 1980s and the beginning of the 1990s have had major impacts on the small-scale agricultural sector in Mexico. The debt crisis of the 1980s led the government to adopt the neoliberal model. Reforms brought by the adoption of this model including trade liberalization, privatization of state-owned enterprises, reduction and cancellation of credits and social programs, along with the relative abandonment of the agricultural sector and focus on the manufacturing and services industries have caused economic, social and environmental harm to corn producers in the Totonacapan region of the state of Veracruz. In order to respond to the impacts of these large-scale policies, farmers coped by migrating to cities and U.S., and by taking advantage of the emergence of alternative markets, such as the corn husk, or totomoxtle, industry. The objective of this study is to explain the context in which totomoxtle emerged and evolved, and determine the importance and impact that this market has had on corn producers, intermediaries and exporters, men, women and children. Based on qualitative data gathered during 2011 using semi-structured interviews, participant observation, and the examination of secondary sources, I found that the totomoxtle trade has expanded considerably in the last decade becoming the main source of income and employment for many marginal households in the Totonacapan. The study questions, however, its ability to be used as a tool for poverty alleviation. Findings suggest that intermediaries and exporters obtain larger profits than farmers thus elucidating the need for more access to capital and infrastructure to achieve higher benefits for growers. At the same time, research also found evidence of the different participation of women and men during the production and manufacturing of totomoxtle. Moreover, research show that women were paid less, work for more hours and they labor in small and crowed places. Finally, data also suggests that the growth of totomoxtle production can be attributed to the increased demand and consumption by Mexican/Latino immigrant populations in the U.S., a shift in the American palate, and its overall availability in new immigrant destinations.Item Developing and Testing a Trafficability Index for Planting Corn and Cotton in the Texas Blackland Prairie(2010-07-14) Helms, Adam J.The Texas Blackland Prairie is one of the most productive agricultural regions in Texas. This region provides a long growing season coupled with soils that have a high water holding capacity. However, the soils also provide significant challenges to producers because the high water holding capacity is a product of a high clay percentage. This research was aimed to develop and test an expert-based trafficabililty index, based upon soil moisture, for planting cotton (Gossypium hirsutum L.) and corn (Zea mays L.) on the Texas Blackland Prairie. Testing the index focused on quantify the potential effect of high soil moisture at planting on seed furrow sidewall compaction and associated plant growth response. Once the trafficability index was developed, three workable soil moisture regimes were recreated in no-tillage and conventional tillage plots at the Stiles Farm Foundation in Thrall, Texas. The index nomenclature included: "Dry-Workable", "Optimal" and "Wet-Workable". After planting corn and cotton into conventional and no tillage plots, 0.45 x 0.20 x 0.15 m intact soil blocks were removed from each plot and kept in a controlled environment. At 28 days, each block was destructively harvested to quantify plant root and shoot growth responses. Each of the three soil moisture indexes was replicated thrice per crop, and the whole experiment was replicated twice in time, n = 48 blocks. The trafficability index was created using three producer experts, and over 10 interviews to collect a range in soil moisture samples. From "Wet Workable" to "Dry Workable", the gravimetric soil moistures were 0.17, 0.22, and 0.26 g g-1. For corn and cotton, a positive relationship between plant growth factors and planting at soil moisture existed. Plants planted at the highest soil moisture emerged faster and developed more root and shoot biomass than those planted at the lowest soil moisture. No evidence of a detrimental plant response because of seed furrow, sidewall compaction from planting at too high a soil moisture content could be quantified. Furthermore, the cotton plants in no-tillage performed better than in conventional tillage, but corn performed better in conventional tillage. Because the results showed an advantage to plant growth by planting in the "Wet Workable" index, the tillage practice that allows the producer to enter the field with a planter at higher moisture contents appears to have an advantage.Item Development and fecundity of the southwestern corn borer (Lepidoptera, Pyralidae) as affected by plant water stress and a secondary host(Texas Tech University, 1985-12) Aslam, MuhammadNot availableItem Economic Analysis of Atoxigenic Mitigation Methods for Aflatoxin in Corn in Central Texas(2014-04-09) Sampson, Jessica SueAtoxigenics and crop insurance are available to producers to assist in preventing economic loss from aflatoxin contamination in corn. Atoxigenics are a newer technology available to farmers, and although professional opinion of this biotechnology encourages its use, an economic analysis has not been performed to determine if the atoxigenics are overall economically beneficial to the producer when combined with crop insurance. The objective of this paper is to perform an economic analysis on the decision to use available atoxigenic treatments on a corn crop, and evaluate the economic outcome at different crop insurance levels for corn producers in Central Texas. This paper will use a risk based partial budget simulation model combined with an aflatoxin contamination simulation model to complete a risk analysis on the decision to use atoxigenic mitigation methods. Field level data on aflatoxin contamination levels is from Bell County, Texas. A representative farm was simulated with and without atoxigenic treatments and each case was simulated across a range of crop insurance options available to corn producers in Bell County. A total of 50 scenarios were simulated and compared based on net revenue. Results show atoxigenics do provide a monetary benefit to producers. When the atoxigenic treatment was compared to no atoxigenic treatment, both with no insurance, the simulated average net revenue was higher by $8-$10 per acre for the treatment scenario. When crop insurance was simulated, with and without atoxigenic treatments, results indicated the current RMA insurance premiums were too high for treatment scenarios. The current RMA premiums did not account for the decreased risk of insurance payout amount and frequency associated with the use of atoxigenics. Current RMA premiums were replaced with fair premiums equal to the simulated mean indemnity payment for all crop insurance options. When the treatment scenario was compared to the no treatment scenario, under the set of most efficient crop insurance options, atoxigenic treatment provided the producer with an additional net monetary benefit of $8-$16 per acre.Item Genetic variation of heat tolerance and correlation with other agronomic traits in a maize (Zea mays L.) recombinant inbred line population(Texas Tech University, 2003-08) Bai, JiangpingHeat stress is a critical environmental factor that affects agricultural production in the southwest of the United States, especially in West Texas. Heat stress can reduce plant height, kill the leaf tissues, cause abortion of pollen and kernel, and affect the cell activities. The objectives of this study were to determine the genetic variation of leaf firing, chlorophyll fluorescence, plant height, ear height, leaves above ear, number of tassel branches, days to flowering and yield per plant in a recombinant inbred line population, and to estimate the heritability of those traits. A total of 179 maize recombinant inbred lines from B76 x B106 were evaluated at Pecos, TX, in 2001, at Texas Tech University (TTU) experimental farm in 2002, and at TAMU Lubbock center in 2001 and 2002. Significant variation in leaf firing, chlorophyll fluorescence and other agronomic traits were found among the RILs. In the population, leaf firing ranged from 0% to 92.9% in Lubbock-TAMU 2001 test, 0% to 100% in Pecos 2001 test, 0% to 67.9% in Lubbock-TAMU 2002 test, and 0% to 100% in Lubbock-TTU 2002 test. The average of chlorophyll fluorescence of the RILs ranged from 0 to 0.79 (2001 Lubbock-TAMU), 0.14 to 0.78 (2002 Lubbock-TAMU), and 0.02 to 0.76 (2002 Lubbock-TTU). Leaf finng,chlorophyll fluorescence and other agronomic traits also showed transgressive segregation in the population in each environment. Only plant height, ear height, number of tassel branches (2001 and 2002 Lubbock-TAMU), and leaves above ear (2002 Lubbock-TAMU) showed the normality distribution. Under heat stress, yield per plant was negatively correlated with percent leaf finng and days to flowering and positively correlated with chlorophyll fluorescence and number of tassel branches. Percent leaf firing was negatively correlated vMth chlorophyll fluorescence. Number of tassel branches was positively correlated with plant height and ear height. Leaf firing and chlorophyll fluorescence did not show strong correlation with plant height, ear height, number of tasel branches, and leaves above ear. The broad-sense heritability for leaf firing and chlorophyll fluorescence was 0.32 and 0.28 on the plot basis, respectively, and 0.85 and 0.77 on the mean basis. From their low heritability based on plot, high heritability based on means, and large genotype x environment interactions, we believe that the heat tolerance in maize is inherited quantitatively, and effective selection for heat tolerance requires evaluation genotypes in replicated trails in multiple environments.Item Phenotypic and genotypic evaluation of generations and recombinant inbred lines for response to aflatoxin(2009-05-15) Bello, Halima ThelmaAspergillus flavus is a fungus pathogen of maize that causes contamination of maize with aflatoxin. Aflatoxin is a carcinogenic toxin that can cause harm to human and animal health. Several management practices have been developed, such as cultural, chemical, biological and breeding, for host resistance. Development of host plant resistance has been the most desirable but this has been hampered by several factors, such as environmental influence, time consuming phenotyping and costly inoculation and field evaluations. Because of the problems associated with breeding for aflatoxin resistance, heritability estimates along with genetic correlations for aflatoxin and its secondary traits were estimated in this study. This experiment was conducted in two Texas locations (College Station and Weslaco) and phenotypic data were collected for aflatoxin concentration, maturity, endosperm texture, percentage of rotten ears and grain yield per ear. The heritability was moderate to high for aflatoxin and secondary traits such as endosperm texture and percentage of rotten ears. Aflatoxin was observed to be negatively correlated to grain yield and positively correlated to percentage of rotten ears. A population of recombinant inbred line derived from a cross between CML161 and B73o2 were evaluated in replicated trials in two environments for resistance to aflatoxin contamination. The families were genotyped using simple sequence repeat (SSR) markers. The mapping Recombinant Inbred Line population was used to detect and characterize Quantitative Trait Loci associated with aflatoxin accumulation. Alleles for reducing aflatoxin contamination came from both parents across the chromosomes. Thirty-eight epistatic interactions were detected for aflatoxin resistance. Several other QTLs were identified for other traits such as grain yield, endosperm texture, and percentage of rotten ears. The QTLs reported in this experiment are promising and need to be validated in other environment and genetic backgrounds for further use in marker assisted selection. Inheritance studies using generation mean analysis in six crosses showed additive and dominance effects to be mainly responsible for aflatoxin resistance. Two inbreds, CML176 and CML161, were identified as sources of resistance in breeding programs and use for selection.Item The economics of precision farming in the Texas High Plains(Texas Tech University, 2002-12) Watson, Susan ElizabethNot available.Item The effect of rate, source, and application method of phosphorus on corn(Texas Tech University, 1977-08) Lange, Allan JosephNot availableItem The effects of herbicides and insecticides used alone and in combination on the growth and development of corn(Texas Tech University, 1991-05) Fitriana, MariaThe objectives of this study were: 1. To evaluate any phytotoxic effects on three corn hybrids from the use of two sulfonylurea herbicides and three insecticides used alone and in combination. 2, To determine any residual effects of the herbicides and insecticides used in this study on subsequent sorghum growth.Item The effects of SarStart DSC (Trademark) and corn processing method on performance and carcass characteristics of finishing beef steers(Texas Tech University, 2001-12) Barrett, Kenneth E.One hundred twenty beef steers (337.6 kg; Angus, Charolais, and Angus x Charolais) were used to test the effects of gram processing method and Sar Start DSC on animal performance and carcass characteristics. Cattle were blocked by body weight (BW) into six blocks and assigned randomly to one of four treatments. Treatments were steam-flaked (SF) corn (SFO), SF corn with 111 mg of SarStart DSC/kg of dietan DM (SF+), dry-rolled (DR) corn (DRO), and DR corn with 111 mg of SarStart DSC/kg of dietary DM (DR+). Cattle were housed in slotted concrete floor pens, five animals per pen, and fed their respective treatment diets. The steers were initially started on an 80% concentrate diet and then stepped up to the final 90% concentrate treatment diets. Body weight was recorded every 28 d, and orts were weighed and analyzed for dry matter (DM). These data were used to determine average daily gain (ADG), dry matter intake (DMI), and feed efficiency. The heaviest three blocks of cattle were fed for 133 d, and the lightest three blocks were fed for 151 d. Carcass measurements taken at slaughter included hot carcass weight, longissimus muscle (LM) area, marbling score, percentage of kidney, pelvic, and heart fat (KPH), back fat thickness, USDA quality grade and yield grades, and liver abscess score. An in vitro DM disappearance (FVDMD) procedure was used to evaluate the dose response of SarStart DSC. Treatments for the IVDMD were DR and SF corn with 0, 27.75, 55.5, 83.25, and 111 mg of SarStart DSC/kg of corn DM arranged m a 2 x 5 factorial. Substrates were incubated at 39°C m 50-mL test tubes for 4. 8, 12, 24, or 48 h in a ruminal fluid buffer solution. Digested substrates were then incubated in an acidified pepsm solution for 48 h. After filtering, digested substrates were dried overnight m a 100°C forced-air oven and analyzed for IVDMD. Cattle that were fed the SF com-based diets consumed less feed (P < .01) and were more efficient at converting feed to gain (P < 0.01) than those fed the DR corn-based diets. The ADG by cattle fed the DR corn-based diet did not differ from that of cattle fed the SF combased diet. The addition of SarStart DSC to the diet did not affect (P > 0.80) animal performance over the feeding period. Carcass data were not affected (P > 0.17) by either grain processmg method or SarStart DSC. There was a grain processing method x SarStart DSC interaction (P < 0.04) for marbling score. SarStart DSC increased the marbling score of cattle fed the SF com-based diet and decreased the marbling score of cattle fed the DR corn-based diet. Quality grade and liver score distributions were not affected by either grain processing method or SarStart DSC. The IVDMD data showed an increase (P < 0.01) in the rate of digestion for SF com compared with DR com; however, there was no difference (P > 0.09) m FVDMD at 48 h between the two grain processing methods. The FVDMD increased linearly as the concentration of SarStart DSC increased for the 4, 12, and 24-h incubations (P < 0.20, 0.02, and 0.01, respectively); however, the FVDMD decreased linearly (P < 0.01) as SarStart DSC increased for the 8-h incubation. SarStart DSC did not affect FVDMD for the 48-h incubation (P > 0.53). The reasons for the inverse relationship between SarStart DSC and FVDMD for the 8-h incubation are unclear. It is concluded that SF corn-based diets improved animal performance compared with DR corn-based diets and that the addition of 111 mg of SarStart DSC/kg of dietary DM did not enhance performance or carcass characteristics of finishing beef cattle.Item The Net Effect of Exchange Rates on Agricultural Inputs and Outputs(2012-10-19) Johnson, Myriah D.For more than thirty years, studies about the effect of the exchange rate on exports have been conducted. However, few have considered the combined effect of the exchange rate on imported inputs into the agricultural system and the exports of final agricultural products those inputs produce. This work contributes to the agricultural economics literature by combining those effects. A current concern is for the net effect as the total value and quantity of inputs imported has increased. This research examines the effect of the exchange rate on imported inputs into the corn, wheat, and beef cattle production systems, breaking it down to a producer's budget, examining how the exchange rate affects profitability. Vector Autoregression (VAR) and Bayesian Averaging of Classical Estimates (BACE) models were estimated to evaluate the effects. Daily and weekly price data were used for corn, wheat, feeder steers, ethanol, diesel, ammonia, urea, di-ammonium phosphate, and the exchange rate. A VAR model was estimated to model the relationship between the variables. After having incongruous test results in determining the lag length structure it was decided that a BACE model would be approximated. After estimating the BACE model, the price responses of the commodities to the exchange rates were estimated. The price responses were used in demonstrating the effect of the exchange rate on a producer's profitability. It was determined that, generally, a strengthening exchange rate has a negative impact on prices. It was also found that the exchange rate has a greater impact on prices now than it did 14 years ago, implying that the exchange rate now has a greater affect on profitability. A one percent increase in the value of the dollar led to a decline in profitability ranging from $0.02/bu in wheat to $0.56/cwt in feeder steers. However, agricultural producers should not be overly concerned about a lower valued dollar from the perspective of their agricultural business.Item Value-enhanced high oil corn for fedlot cattle(Texas Tech University, 2001-08) Bramble, Tyler ColeTwo experiments were conducted to investigate the effects of steam-flaking and feeding high-oil Corn (HO) to finishing feedlot steers. In experiment 1, 16 crossbred teers were fed a diet containing either typical corn (T) or HO steam-flaked to either 0.31 kg/L (24) or 0.36 kg/L 28) for 127 d to determine effects on feedlot performance a carcass characteristics. Diets were balanced by including HO into the diet at 75% of DM whereas T as included at 72% of diet DM with 2.8% added fat. Overall average daily gain (ADG) and dry matter (DM) intake were unaffected (P > 0.10) by flake density or by corn variety. However, feed-to-gain (FG) was superior (P < 0.05) for HO-24 as compared to T-24 and HO-28. Carcass characteristics were unaffected (P > 0.10) by treatments. Results indicate that HO can replace T plus added fat in feedlot diets, and more extensive processing (lower flake density) of HO will enhance its feeding value.Item Yield and quality responses of corn silage genotypes under reduced irrigation in the Texas High Plains(2012-05) Spinhirne, Bruce; Xu, Wenwei; Dotray, Peter A.; Doerfert, DavidTwo main options exist for producers to optimize the production of corn silage in limited-irrigation systems. First, they can utilize best management practices to make optimum use of inputs. Secondly, they can select hybrids that will maximize production from limited inputs. The intent of this study was to explore both options by characterizing the effects of moisture stress on silage corn and by comparing relative performance of a diverse group of silage corn hybrids. The overall objective of this study was to determine genotype effects of 20 silage corn hybrids and the effects of environmental stress on silage corn yield and quality. Environmental stress was considered to be primarily caused by the deficit of moisture inputs to crop demand. To adequately accomplish this objective, four sub-objectives were created.