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1
Bauer, Matthew J. "The interploidy hybridization barrier in Zea Mays L." Diss., Columbia, Mo. : University of Missouri-Columbia, 2006. http://hdl.handle.net/10355/4448.
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Thesis (Ph. D.) University of Missouri-Columbia, 2006.The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on July 31, 2007) Includes bibliographical references.
2
Lamb, Jonathan C. "Centromere function and evolution in maize (Zea mays)." Diss., Columbia, Mo. : University of Missouri-Columbia, 2006. http://hdl.handle.net/10355/4446.
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Thesis (Ph. D.) University of Missouri-Columbia, 2006.The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on August 3, 2007) Includes bibliographical references.
3
Dogra, Anjali. "A genetic and molecular characterization of heterosis in Zea mays /." free to MU campus, to others for purchase, 2000. http://wwwlib.umi.com/cr/mo/fullcit?p9998480.
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Chou, Tau-San Weber David F. "Sister chromatid exchanges in Zea mays L." Normal, Ill. Illinois State University, 1985. http://wwwlib.umi.com/cr/ilstu/fullcit?p8514768.
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Thesis (Ph. D.)--Illinois State University, 1985.Title from title page screen, viewed June 7, 2005. Dissertation Committee: David F. Weber (chair), Herman Brockman, Tsan Iang Chuang, Alan Katz, Derek McCracken. Includes bibliographical references (leaves 118-142) and abstract. Also available in print.
5
Azar, Christian. "Characterization of white floury corn (Zea mays L.) landraces of Ontario." Thesis, McGill University, 1996. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=23867.
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Data were collected on 24 traits to characterize and classify 35 white floury corn (Zea mays L.) landraces collected on native reserves in Ontario. Several landrace x landrace and landrace x inbred crosses were evaluated. Test crosses were made to determine whether the landraces carry the floury-l (fl$ sb1$) allele. Most traits examined exhibited considerable variation among the landraces. Variation was also observed within many of the landraces for ear and cob colour, for endosperm texture and row number. The landraces were grouped into 10 clusters by centroid clustering analysis. Significant heterosis over the mid-parent value was observed in the crosses among landraces. Some crosses between landraces and inbreds yielded more than either parent. Crossing the landraces with the inbreds improved some agronomic characteristics, but disrupted some of the ear characteristics of the landraces. The floury factor responsible for the characteristic endosperm texture of the IAPO landraces was identified as being the dosage dependent fl$ sb1$.
6
Schneerman, Martha June Cook Weber David F. "Identification of quantitative trait loci (QTLs) of corn oil in Zea mays L." Normal, Ill. Illinois State University, 1996. http://wwwlib.umi.com/cr/ilstu/fullcit?p9720812.
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Thesis (Ph. D.)--Illinois State University, 1996.Title from title page screen, viewed May 31, 2006. Dissertation Committee: David F. Weber (chair), Alan J. Katz, Marjorie A. Jones, Radheshyam K. Jayaswal, Jefferey A. Dole. Includes bibliographical references (leaves 96-108) and abstract. Also available in print.
7
King, Steve Russell. "Double-crop corn (zea mays) weed control in Virginia." Thesis, Virginia Tech, 2000. http://hdl.handle.net/10919/32469.
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Double-crop production of corn (Zea mays L.) for grain following the harvest of small grain is not currently practiced in Virginia. Historical precipitation and evapotransportation data indicate that delayed corn planting could result in a higher probability of moisture during critical periods of crop development. Double-crop corn may also reduce economic risk as two crops would be harvested in the same year. Field experiments were conducted in three Virginia locations in 1998 and 1999 to determine the herbicide inputs required for double-crop corn production relative to those required in full-season no-till corn production. Experiments were conducted in a split-plot, randomized complete block design with cropping system as the main plot and herbicide treatment as the subplot. Herbicide treatments included combinations of nonselective herbicides for no-till establishment and/or preemergence residual herbicides and/or selective postemergence herbicides in both production systems. Glyphosate-tolerant corn was planted in all experiments and postemergence glyphosate treatments were also evaluated. In each experiment, dependent variables included weed control by species evaluated throughout the season, as well as weed biomass and corn yield evaluated at the end of the growing season. Generally, nonselective herbicides were not required in the double-crop system where atrazine was applied as a preemergence treatment, or where selective postemergence treatments were applied. Where a significant proportion of the infestation was comprised of perennial species, however, atrazine treatments were not sufficient in the double-crop system. Postemergence glyphosate treatments provided excellent broad-spectrum weed control in this situation. In heavy annual grass infestations, postemergence glyphosate treatments provided superior weed control to preemergence treatments alone, and equivalent weed control to treatments in which both preemergence and postemergence herbicides were applied. Corn yield response to weed control and cropping system variables varied significantly between the 1998 and 1999 growing seasons. Where adequate late-season rainfall was received, economic return from small grain and corn crops in the double-crop system was higher than the return in the full-season system, particularly in infestations where the double-crop system allowed significant reduction in herbicide input.Master of Science
8
Miller, Nathaniel Douglas. "Management of burcucumber (Sicyos angulatus) in corn (Zea mays)." The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1322616069.
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Ferguson, Christopher G. "Effect of Tassel Removal for Baby Corn (Zea mays L.) Production in Kentucky." TopSCHOLAR®, 2012. http://digitalcommons.wku.edu/theses/1157.
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Baby corn (Zea mays L.) consists of unfertilized young ears harvested at silkemergence. The 2011 study was a culmination of four successive years of productionand evaluation of baby corn at Western Kentucky University (36.93 N, 86.47 W). Theobjective was to compare the effect of tassel removal on baby corn (BC) production onfour cultivars of corn, two field (‘N77P-3000GT’, ‘N68B-3000GT’) and two sweet(‘Silver Queen’, ‘Peaches N Cream’). Results indicated that tassel removal gavesignificant increases (P<0.01) of BC ears across harvests (H) and cultivars; however, the effect was not consistent over treatments. For harvests, the difference due to detasseling was significant (P<0.05) for H2 and H3, but not significant (P>0.05) for H1 or H4. For cultivars, numerical values were higher for detasseled than non-detasseled treatments in the first three harvests for each cultivar, but significant (P<0.05) only for ‘Peaches n’ Cream’. Quality of BC from both tassel treatments decreased in H3 and H4. Based upon the increased number of ears resulting from detasseling, additional labor costs would be more than covered. Baby corn has excellent potential as a niche crop for producers and consumers in Central Kentucky.
10
Deng, Yinghai 1966. "Development and disease resistance of leafy reduced stature maize (Zea mays L.)." Thesis, McGill University, 2001. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=38177.
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Previous studies on Leafy reduced-stature (LRS) maize found that it had extremely early maturity and a higher harvest index (HI), leading to high yields for its maturity rating. Whether this apparent high HI is relaxed to its earliness, or can also exist among the medium or late maturity LRS maize has not been previously investigated. It was also of interest to know if the traits that produced the LRS canopy structure have pleiotropic effects on root architecture. Finally, field observations indicated that LRS maize had a lower incidence of common smut. It is not known whether this apparent resistance is specific to smut or includes other diseases.Using a wide range of the most recently developed LRS hybrids and some conventional hybrids, a two-year field experiment was conducted to examine the HI and disease resistance of LRS maize. HI, yield, and yield components were compared between the two genotype groups (LRS and conventional) under different population densities. The resistance to the natural incidence of common smut and artificially inoculated Gibberella ear rot was also tested. Morphology and fractal dimension analyses of roots at an early development stage were conducted in indoor experiments. These analyses were performed with WinRHIZO (version 3.9), an interactive scanner-based image analysis system.
This work showed that: (1) There was no relationship between the HI and maturity; higher HIs can also exist among the medium and late maturity LRS hybrids. (2) While LRS maize hybrids have the potential for high yield this was not realized in the LRS hybrids used in this work. Further breeding and development of optimum management practices are needed to fully exploit this potential. (3) During early development LRS hybrids generally had more branching and more complex root systems than conventional hybrids. (4) Fractal dimension, as a comprehensive estimation of root complexity, was highly related to major root morphological variables, such as root total length, surface area, branching frequency and dry mass. (5) Of the hybrids tested the greatest resistance to both common smut and Gibberella ear rot, two major ear diseases, occurred in some of the LRS types.
11
Jordan, Berry Lyn. "Investigation of the developmental profile of chromosomal proteins in Zea mays." Thesis, North Texas State University, 1985. https://digital.library.unt.edu/ark:/67531/metadc798070/.
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Histone proteins were examined during development in the meiotic elongate and a genetically close line N6HT. Histones were also extracted from an F1 (el x N6Ht). Comparisonc beteen the histone samples from each line of N6HT and elongate, and the F1 for leaf, root, and stem were inconclusive. A tassel sample form elongate exhibited a markedly slower migrating band that was not present in N6HT. The histone profiles of elongate and N6HT also differed. Each line N6HT and elongate exhibited three protein bands in the H1 region. Maize histone samples have been shown to exhibit four major H1 bands. The possibility exists that an H1 protein altered in its molecular weight and possibly in its interaction with the chromosome is present in elongate.
12
Williams, Bruce. "Isolation and characterization of abscisic acid-responsive, embryo specific genes from Zea mays." Thesis, McGill University, 1993. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=41786.
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Embryogenesis in plants, as in animals, requires the regulated expression of sets of genes involved in developmental processes. To gain insight into the processes regulating gene expression during embryogenesis differential screening was used to identify embryo-specific sequences in a cDNA library constructed from Zea mays embryo RNA. Four embryo-specific sequences and one constitutive sequence were characterized further by RNA blot hybridization and DNA sequence determination. The constitutive sequence and two of the embryo-specific sequences were found to encode parts of the previously-reported chloroplast 23S rRNA, Oleosin KD-18, and RAB-17 genes. Two sequences, named Emb5 and Emb564, were found to encode novel maize homologs of a gene expressed during late embryogenesis in a wide range of seed plants. These 5 genes exhibited differential temporal and spatial accumulation during development. Moreover, analysis of RNA from cultured embryos suggested that 4 of these genes were regulated by abscisic acid. The ABA-responsive genes could be divided into 3 classes, based on their developmental expression, tissue-specificity, and sensitivity to ABA. Antibodies raised against a $ beta$-galactosidase:EMB564 fusion protein were used to analyze the accumulation of the EMB564 and/or EMB5 proteins. These polyclonal antibodies detected one or several polypeptides with a molecular weight less than 14 kD which exhibited patterns of developmental accumulation and regulation similar to Emb5 and Emb564 transcripts.
13
Ketchum, Karen Ann. "A calcium-dependent potassium channel in corn (Zea mays) suspension cells /." Thesis, McGill University, 1990. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=74658.
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Three distinct K$ sp+$ currents were identified in corn (Zea mays) protoplasts using the whole-cell patch-clamp technique. Inward-rectifying K$ sp+$ currents were evoked at membrane potentials more negative than $-$100 mV. The activation range was sensitive to external K$ sp+$ and shifted in the positive direction as the K$ sp+$ concentration was elevated. The second K$ sp+$ current was voltage-independent and contributed to the resting membrane conductance of the protoplast. Finally, a voltage- and Ca$ sp{2+}$-dependent K$ sp+$ current was observed at potentials positive to $-$60 mV. This current was inhibited by reagents which antagonize plasmalemma Ca$ sp{2+}$ influx (e.g. nitrendipine, verapamil). In contrast, currents were enhanced by increasing the cytosolic free Ca$ sp{2+}$ concentration from 40 to 400 nM. The Ca$ sp{2+}$-dependent K$ sp+$ current was inhibited by tetraethylammonium ions, Cs$ sp+$, Ba$ sp{2+}$, and charybdotoxin which suggested that the channel protein has structural similarities to the high conductance Ca$ sp{2+}$-dependent K$ sp+$ channel observed in animal systems.
14
Smith, Chad Lee Smeda R. J. "Weed management and nitrogen loss in glyphosate-resistant corn (Zea mays)." Diss., Columbia, Mo. : University of Missouri--Columbia, 2009. http://hdl.handle.net/10355/6568.
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The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Title from PDF of title page (University of Missouri--Columbia, viewed on January 22, 2010). Thesis advisor: Dr. Reid J. Smeda. Includes bibliographical references.
15
Polius, J. J. N. "Micronutrient nutrition of maize (Zea mays L.) as influenced by fertilizers, hybrids, irrigation and plant population density." Thesis, McGill University, 1987. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=63809.
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Spaner, Dean Michael. "Maize (Zea mays L.) production in Trinidad & Tobago : development, agronomic, and breeding perspectives." Thesis, McGill University, 1996. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=40447.
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Increasing maize production in Trinidad & Tobago could reduce imports and lessen dependency on foreign markets for food and feed. A review of large maize development projects and a survey of maize farmers on small landholdings indicated that mechanized production of maize grain is technically and economically impractical. Maize is normally grown and harvested in the green immature stage by small-scale farmers as a fast, easy, and relatively profitable sideline vegetable crop. An imported hybrid and an improved local landrace (ICTA Farm Corn) yielded more green maize than a Mexican-bred locally-distributed variety, following early (June) rainy season plantings. Hybrid and local unimproved open-pollinated maize were grown with two levels of weed control and with two levels of fertilizer application following late (November) rainy season plantings. For commercial carnival season production of green maize on productive soils in Trinidad, the purchase of imported hybrid seed is economically justifiable, but high inputs into weed control and fertility management may not be needed. A consumer preference study of the main varietal types eaten as boiled ears indicated panelists could not discern differences when seasoned with Creole seasoning, but preferred yellow, large-eared varieties when not seasoned. In a series of 11 variety trials on Inceptisolic and Ultasolic soils in Trinidad, imported hybrids and ICTA Farm Corn consistently yielded greater than 9 other varieties. Grid mass selection for ear weight and ear size was carried out in ICTA Farm Corn. Green maize ear length (1.9% cycle$ sp{-1}$), width (1.5% cycle$ sp {-1}$), and ear weight (2.4% cycle$ sp{-1}$) increased linearly with selection, leading to increases in green marketable (4.4% cycle$ sp{-1}$), green total (3.0% cycle$ sp{-1}$), and grain yield ha$ sp{-1}$ (4.3% cycle$ sp{-1}$). Phenotypic correlations indicated high levels of association between grain yield and both green marketable ear weight (r = 0.91
17
Helmy, Magdi Mourad Mohammed. "Salinity-fertility interaction with macro and micronutrients in maize (Zea mays) plants." Diss., The University of Arizona, 1987. http://hdl.handle.net/10150/184298.
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In two greenhouse experiments, the response of maize plants (Zea mays L.) to macro and micronutrient fertilizers was studied. The first experiment was conducted in Cairo, Egypt in which maize plants were grown on saline soils with ECₑ values of 1.42, 6.12 and 12.1 dSm⁻¹ and fertilized with N, P, K alone and in combination. It was found that maize plants produced the highest dry matter when NP fertilizers were added in the Ca-form compared to the other fertilizer treatments, and this positive response decreased with increasing salinity level. Also, it was found that application of P and K fertilizers either alone or together as PK augmented the adverse effect of salinity on dry matter and nutrients uptake. In addition, the concentration and uptake of Na⁺ ions in the shoot tissues decreased with increasing salinity level up to ECₑ 12 dSm⁻¹. This could be due to Na+ exclusion or accumulation in root tissues. However, application of N and P fertilizers tended to decrease plant content of micronutrients, particularly Fe as well as Zn at high salt levels. The second experiment was conducted in a University of Arizona campus greenhouse. A Pima soil from the Marana area was artificially salinized with NaCl, Na₂SO₄, CaCl₂, and Mg₂SO₄ salts almost to the salinity levels mentioned above. Maize plants were grown and fertilized with NP fertilizer as a basic dressing. Chelated forms of Zn, Fe, and Mn were added with two different methods; soil and foliar spray application. Two pH values of spray nutrient solutions were used; pH 6 and pH 8. Data obtained showed increased dry matter and nutrient uptake in response to spraying maize plants with Zn + Fe or Zn+ Fe + Mn at pH value of 8 at the medium salt level relative to the other treatments. However, maize plants also showed high dry matter and nutrient uptake in response to Zn + Fe + Mn soil application at the high salt level, although Zn-pH 8 gave unexpectedly high dry matter production. It seems probable that this high dry matter obtained could be due to the effect of high pH spray treatment on increasing the activity of some enzymes, e.g. PEP-carboxylase and/or ribulose 1,5 diphosphate carboxylase, as well as the increase in rate of translocating the photosynthates and this effect was augmented by the nutrient(s) applied. Also, it was found that Na uptake decreased while total chlorophyll and chlorophyll a content increased with increasing salinity level. The increase in the chlorophyll content could be due to either Na exclusion by the plants and/or the decrease plant growth due high salts.
18
Albuquerque, Fernando Alves de [UNESP]. "Comportamento e dano de tripes na cultura do milho (Zea mays L.)." Universidade Estadual Paulista (UNESP), 2004. http://hdl.handle.net/11449/105422.
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Universidade Estadual Paulista (UNESP)
Com o objetivo de identificar as possíveis espécies de tripes associadas à cultura do milho, a espécie predominante, a proporção de adultos e ninfas, a época de ocor-rência, o período crítico de ataque e a influência do sistema de plantio e das condições climáti-cas sobre a população de tripes e métodos de amostragem, foram conduzidos ensaios na Fa-zenda Experimental de Iguatemi, localizada no Município de Maringá, PR, no período de ou-tubro de 2001 a fevereiro de 2004. As avaliações foram realizadas por meio da coleta de tri-pes com armadilhas adesivas azuis e coletando-se plantas de milho, cortadas rente ao solo, colocadas em sacos plásticos e levadas ao laboratório, onde foram lavadas em álcool 70%, para extração dos tripes. A determinação dos danos provocados pelo tripes foi estudada em cinco experimentos inteiramente casualizados, correlacionando diferentes níveis populacionais de tripes e produtividade. Foi empregado o inseticida thiamethoxan, em tratamento de semen-tes, e pulverizações com metamidofós, em diferentes estágios de desenvolvimento das plantas, para obter parcelas com diferentes níveis de incidência de tripes em períodos pré-determinados. Foram identificadas oito espécies de tripes associadas à cultura do milho, na região, sendo Frankliniella williamsi Hood, 1915, a mais freqüente (99,43%). Verificou-se que a incidência de tripes na cultura de milho em solo coberto com aveia dessecada foi menor do que em solo nu, ou coberto por aveia tombada ou incorporada, sendo que imediatamente após a emergência das plantas a população de tripes era composta quase que exclusivamente por adultos imigrantes. A população de formas jovens começou a aumentar a partir dos 14 dias após a emergência das plantas, indicando a capacidade reprodutiva do tripes na cultura do milho. Foi verificada correlação negativa entre... .
Aiming to identify the possible species of thrips associated to the corn crop, the predominant species, the adult/nymph rate, occurrence time, critical period of attack, influence of the sowing system and climatic conditions on the population of thrips and sampling methods, essays were carried out at the Experimental Farm of Iguatemi, in Maringá, Paraná State, Brazil, from October 2001 to February 2004. The evaluations consisted in collecting thrips with blue adhesive traps and collecting corn plants cuted at soil level, placed into plastic bags and took to the laboratory, where they were washed in alcohol 70%, for the extraction of thrips. The determination of the damages caused by thrips was studied in five experiments, totally randomized, correlating different population levels of thrips and productivity. The insecticide thiamethoxan was applied in seed treatment and methamidophos, in sprayings in different stages of plant development to obtain areas with different levels of incidence of thrips in periods previously established. Eight species of thrips associated to corn crop were identified in the area, being Frankliniella williamsi Hood, 1915, the most frequent (99.43%). It was verified that the incidence of corn thrips in soil covered with dried oats was smaller than in nude soil or in soils covered by cuted or incorporated oat, considering that, immediately after the plants emergence, the population of thrips was composed almost exclusively by emigrant adults. The young population began to increase from 14 days after plant emergence, on indicating thrips reproductivity capacity in corn crops. Negative correlation was verified between the rainfall index and the number of thrips collected in blue traps, but it was not observed any correlation among the number of thrips by corn plant and the number of thrips collected in those traps. It was verified that more than 30 thrips... (Complete abstract, click electronic address below).
19
Lopez, Collado Catalino Jorge. "A conceptual model to estimate the nitrogen requirement of corn (Zea mays L.)." Diss., Texas A&M University, 2005. http://hdl.handle.net/1969.1/4846.
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The objectives of this work were to evaluate the vegetative parameters used to estimate crop N demand and to estimate the accuracy and precision of the conceptual model of fertilization using an error propagation method. Corn plants were collected throughout the entire crop life cycle to determine the fresh and dry weight of the aboveground biomass and roots, root index, plant height, and corn grain yield. Three experiments were conducted, two under field conditions and one under greenhouse conditions. In the first field experiment in 2002, three sites were selected. The first site was the Texas A&M University (TAMU) Agricultural Experiment Station Research Farm in which a Ships clay soil was used. The second site was a cooperative farmer's land on a Weswood silt loam soil in Burleson County. These first two sites used Pioneer 32R25 as the corn hybrid. The third site was also a Ships soil in the TAMU Farm, but Dekalb 687 was the corn variety. In 2003, the second experiment was on a Ships soil in the field of TAMU Farm, and the third experiment was conducted in a greenhouse using Ships and Weswood soil. No differences in the root index and harvest index were observed, even when the Dekalb 687 hybrid was included. Variations in plant N concentration, moisture content, and yield were noted, but followed predictable patterns with time over the season. These parameters were consistent throughout the entire life cycle of the crop. The linear relationship between the fresh weight of aboveground biomass and fresh weight of roots was R2 = 0.92, the moisture content of corn plants over time was fit to a second grade polynomial with R2 = 0.98, and plant N content had a close linear relationship (R2=0.90) with the total plant dry weight, including roots, at harvest. The accuracy of the conceptual model was low under field conditions (55%), but high under greenhouse conditions (90%). Precision of the conceptual model was low both in the field (194%) and the greenhouse (115%) conditions.
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Greyson, Philip R. "Corn (Zea mays L.) production in a grass/clover living mulch system." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ36453.pdf.
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Abdaoui, Fatima El. "Allelopathic effects of ferulic, gallic, and vanillic acids on corn (Zea mays L.)." Diss., Virginia Tech, 1991. http://hdl.handle.net/10919/39816.
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Studies on the activity of femlic, gallic, and vanillic acids on germination
and growth of corn (Zea mays L.), radish (Raphanus sativus L.), and peanut
(Arachis hypogaea L.) showed that the inhibitory effects of these acids were
concentration and growth variable dependent. Ten days after treatment,
significant reduction in percent germination of the three species occurred with
higher phenolic acid treatments, except that gallic acid did not significantly inhibit
peanut germination. Among the growth parameters investigated, root elongation
and dry weight were more affected than either germination or shoot length and
dry weight. Radish and corn were more sensitive than peanut.
In two-combination experiments, the interactive effects of phenolic acids on
corn germination and shoot growth were generally not significant, indicating an
additive effect. Femlic acid, generally, antagonized higher concentrations of
vanillic or gallic acids on corn root length and dry weight, suggesting a differential
uptake of phenolic acids by corn roots or a limited uptake of gallic and vanillic
acids in the presence of ferulic acid. In a soil system, higher and repeated
phenolic acid treatments were required to bring about inhibition of corn growth
than those which were effective in petri dishes.
All levels of the synthetic auxin, 2,4-D (2,4-dichlorophenoxyacetic acid) were
effective in reversing the inhibitory effects of 1 mM ferulic acid on corn root
length when these two acids were applied in combination. No 2,4-D treatment
counteracted 10 mM of ferulic acid. All levels of 2,4-D combined with 1 mM
ferulic acid and the mixture of 0.1 nM 2,4-D with 10 mM ferulic acid were
antagonistic for corn shoot length. No significant interactions were obtained on
corn germination or seedling growth when 2,4-D was combined with gallic acid.
Using manometric techniques, no inhibitory effects of ferulic or gallic acids
observed on 02 consumption of germinating corn seeds. Ferulic acid did not
interfere with water uptake of corn seeds during imbibition and germination.
These findings indicate that the phytotoxicity of these acids observed on corn
germination and seedling growth are not due to their interference with water
uptake and respiratory activity of germinating seeds.Ph. D.
22
Antenucci, Robert Nicholas. "Isolation and characterization of ferulic acid carbohydrate esters from corn hull (Zea mays)." Diss., Virginia Polytechnic Institute and State University, 1988. http://hdl.handle.net/10919/53672.
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Refined corn hulls (bran) were hydrolyzed with 30 mM oxalic acid in order to release carbohydrate fragments containing ferulic acid. The fragments which were high in ferulic acid also contained high levels of arabinose, xylose, and galactose, which are characteristic of sugars comprising corn hull hemicellulose side chains. Corn hull hydrolysate fragments were fractionated by chromatography to obtain purified feruloyl oligosaccharides. A The structure of the major feruloyl compounds were characterized by analysis of the products of acid, alkali, and enzyme hydrolysis, in combination with carbon-13 and 2D proton NMR spectroscopy. Three feruloyl oligosaccharides were identified as 5-0-(trans)-feruloyl-L-arabinofuranose (FA), 2-0-β-xylopyranosyl-(5-0-trans-feruloyl arabinofuranose) (FXA), and 0-(6-0-trans-feruloyl-α-D-galactopyranosyl)-(1-4) -O-β-D-xylopyranosyl-(1-2)-L-arabinofuranose (FGXA).Ph. D.
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Pfunde, Cleopatra Nyaradzo. "Parent characterization of quality protein maize (Zea mays L.) and combining ability for tolerance to drought stress." Thesis, University of Fort Hare, 2012. http://hdl.handle.net/10353/d1007536.
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Quality protein maize (QPM) has enhanced levels of two essential amino acids, lysine and tryptophan compared to normal maize. This makes QPM an important cereal crop in communities where maize is a staple crop. The main abiotic factor to QPM production is drought stress. Little information is available on the effect of drought stress on QPM. Therefore, the objectives of this study were to: (i) conduct diversity analysis of QPM inbred lines using morpho-agronomic and simple sequence repeat markers, (ii) screen available QPM inbred lines and F1 progeny for tolerance to seedling drought stress, (iii) determine the combining ability and type of gene action of QPM inbred lines for tolerance to seedling drought stress, grain yield and endosperm modification. The study was conducted in South Africa, at the University of Fort Hare. Morphological characterisation of 21 inbred lines was done using quantitative and qualitative traits. A randomised complete block design with three replicates was used for characterizing the inbred lines in the field. Genstat statistical software, version 12 (Genstat ®, 2009) was used for analysis of variance (ANOVA) and descriptive statistics. Analysis of variance was performed on all quantitative data for morphological traits. Data for qualitative traits was tabulated in their nominal classes. Traits that contributed most to the variation were days to anthesis, days to silking, anthesis-silking interval, plant height, number of kernel rows, ear length and grain yield. Cluster analysis grouped the inbred lines into three main clusters. The first cluster was characterised by tall and average yielding lines, while the second cluster showed the least anthesis-silking interval, and had the highest yield. Cluster three consisted of lines that were early maturing, but were the least yielding. Genetic distances between maize inbred lines were quantified by using 27 simple sequence repeat markers. The genetic distances between genotypes was computed using Roger’s (1972) genetic distances. Cluster analysis was then carried out using the neighbour-joining tree method using Power Marker software version 3.25. A dendrogram generated from the genetic study of the inbred lines revealed three groups that concurred with expectations based upon pedigree data. These groups were not identical to the groups generated using morpho-agronomic characterisation. Twenty one QPM inbred lines were crossed using a North Carolina design II mating scheme. These were divided into seven sets, each with three inbred lines. The three inbred lines in one set were used as females and crossed with three inbred lines in another set consisting of males. Each inbred line was used as a female in one set, and as a male in a second set. Sixty three hybrids (7 sets x 9 hybrids) were formed and evaluated in October 2011, using a 6x8 alpha-lattice incomplete block design with three replicates under glasshouse and optimum field conditions. A randomised complete block design with three replicates was used for the 21 parental inbred lines. Traits recorded for the glasshouse study were, canopy temperature, chlorophyll content, leaf roll, stem diameter, plant height, leaf number, leaf area, fresh and dry root and shoot weights. Data for the various traits for each environment, 25 percent (stress treatment) and 75 percent (non-stress) of field capacity, were subjected to analysis of variance using the unbalanced treatment design in Genstat statistical package Edition 12. Where varietal differences were found, means were separated using Tukey’s test. Genetic analyses for grain yield and agronomic traits were performed using a fixed effects model in JMP 10 following Residual Maximum Likelihood procedure (REML). From the results, inbred lines that were not previously classified into heterotic groups and drought tolerance categories were classified based on their total dry weight performance and drought susceptibility index. Inbred lines L18, L9, L8, L6 and L3, in order of their drought tolerance index were the best performers under greenhouse conditions and could be recommended for breeding new varieties that are tolerant to seedling drought stress. Evaluation of maize seedlings tolerant to drought stress under glasshouse conditions revealed that cross combination L18 x L11 was drought tolerant, while cross L20 x L7 was susceptible. Total dry weight was used as the major criteria for classifying F1 maize seedlings as being resistant or susceptible. General combining ability effects accounted for 67.43 percent of the genetic variation for total dry weight, while specific combining ability effects contributed 37.57 percent. This indicated that additive gene effects were more important than non-additive gene action in controlling this trait. In the field study (non-drought), the experimental design was a 6x8 alpha lattice incomplete block design with three replicates. On an adjacent field a randomised complete block design with three replicates was used to evaluate the parental inbred lines. The following variables were recorded: plant height, ear height, ears per plant, endosperm modification, days to silking and days to anthesis, anthesis-silking interval, number of kernels per row, number of rows per ear and grain yield. General analyses for the incomplete lattice block design and randomised complete block design for hybrid and inbred data respectively were performed using JMP 10 statistical software. Means were separated using the Tukey's test. Genetic analyses of data for grain yield and agronomic traits were conducted using a fixed effects model using REML in JMP 10. The importance of both GCA (51 percent) and SCA (49 percent) was observed for grain yield. A preponderance of GCA existed for ear height, days to anthesis, anthesis-silking interval, ears per plant and number of kernels per row, indicating that predominantly, additive gene effects controlled hybrid performance under optimum field conditions. The highest heritability was observed for days to silking (48.27 percent) suggesting that yield could be improved through selection for this trait. Under field conditions, variation in time to maturity was observed. This implies that these inbred lines can be recommended for utilisation in different agro-ecologies. Early maturing lines such as L18 can be used to introduce earliness in local cultivars, while early maturing single crosses such as L18 x L2, L5 x L9, L3 x L4 and L2 x L21 could be recommended for maize growers in drought prone areas such as the former Ciskei. Single crosses L18xL11, L16xL18, L8xL21 and L9xL6 had good tolerance to seedling drought stress. On the other hand, single crosses L18xL11 and L11xL13 had high grain yield and good endosperm modification. All these single crosses could be recommended for commercial production after evaluation across locations in the Eastern Cape Province. Alternatively they can be crossed with other superior inbreds to generate three or four way hybrids, which could then be evaluated for potential use by farmers in the Eastern Cape.
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Brunet, Francine. "Intercropping and mechanical weeding : effects on insects of Zea mays." Thesis, McGill University, 1996. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=23990.
Full textAbstract:
A study was undertaken from 1993 to 1994 to determine the effects of intercropping (with Glycine max L Merr., Lupinus sp., Trifolium pratense L.-Lolium multiflorum Lam., or Secale cereale L.) and mechanical weeding (with a rigid tines cultivator, Danish tines cultivator or ridge cultivator) on the population dynamics of insect pests (Diabrotica longicornis Say, Lygus lineolaris Palisot de Beauvois, Ostrinia nubilalis Hubner, and Pseudaletia unipuncta Haworth) on corn (Zea mays L.) in L'Assomption and Sainte-Anne-de-Bellevue, Quebec, Canada.D. longicornis or P. unipuncta populations did not increase.
In 1994, intercropping with T. pratense-L. multiflorum (Sainte-Anne-de-Bellevue) or weeding with the Danish tines cultivator (L'Assomption) increased L. lineolaris populations.
In 1994, intercropping with S. cereale (L'Assomption) ot T. pratense-L. multiflorum (Sainte-Anne-de-Bellevue) increased O. nubilalis populations.
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Zhao, Zuo-Yu Weber David F. "Analysis of nondisjunction induced by the r-X1deficiency and the effect of nullisomy during microsporogenesis in Zea mays." Normal, Ill. Illinois State University, 1988. http://wwwlib.umi.com/cr/ilstu/fullcit?p8818723.
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Thesis (Ph. D.)--Illinois State University, 1988.Title from title page screen, viewed September 14, 2005. Dissertation Committee: David F. Weber (chair), Herman E. Brockman, Robert W. Briggs, Alan J. Katz, Glen E. Collier. Includes bibliographical references (leaves 104-111) and abstract. Also available in print.
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Batlang, Utlwang. "Studies With Triazoles to Alleviate Drought Stress in GreenHouse-Grown Maize (Zea mays) Seedlings." Thesis, Virginia Tech, 2006. http://hdl.handle.net/10919/33428.
Full textAbstract:
In semi-arid environments, dry-land farming often exposes crops to drought stress. Although some plant species are well adapted to drought, most crops are not. Drought can reduce plant populations and limit growth and development in ways that have serious yield consequences. Planting at the beginning of the wet season, when rainfalls are often sporadic and unreliable, can expose young maize seedlings to severe drought. Through the use of plant growth regulators (PGR), maize seedlings can perhaps be altered to elicit responses that mimic drought adaptation mechanisms. A series of studies conducted in the laboratory and greenhouse looked at the response of maize seedlings (two hybrids that differed in their reported drought sensitivity) to severe drought and to PGR applications with or without drought. Results showed that drought stress altered plant morphology and key physiological parameters. Applications of three triazoles (paclobutrazol, uniconazole and tetraconazole) altered morphology and physiology in ways that might impart drought resistance. Paclobutrazol and uniconazole increased root:shoot ratio in laboratory studies and in the greenhouse. When compared to non-triazole-treated controls, uniconazole and paclobutrazol treatments caused water conservation in earlier stages of drought stress, and therefore afforded increased transpiration (and presumably less stress) at later stages. Uniconazole and tetraconazole increased photosynthesis of well-watered plants. Proline content was increased to a greater degree by these same two triazoles under drought stress conditions. It is hoped that knowledge obtained from these studies can be extended to drought-prone areas where maize dry-land farming is practiced.Master of Science
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Nelson, Amy Jane. "Studies on growth and gravitropism in roots of Zea mays using a computer-based video digitizer /." The Ohio State University, 1986. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487323583620111.
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Begna, Sultan Hussein. "Response of leafy reduced-stature maize (Zea mays L.) hybrids to plant population densities and planting patterns in a short-season area." Thesis, McGill University, 1996. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=27278.
Full textAbstract:
The yield of short-season hybrids is lower than long-season hybrids, mainly as a result of the low final leaf area developed by the short-season plants. This is due to the smaller plant stature and smaller leaf number and size of short-season adapted hybrids. In addition, in short-season areas the thermal-time available may be insufficient to mature grain of current maize hybrids. Maize hybrids which accumulate leaf area quickly, mature earlier, yield well and tolerate higher population densities better than the currently available hybrids would be more suitable for production in short-season areas. The "Leafy reduced-stature" maize hybrids, which have only recently been developed, have traits which address these criteria. There has been no previous effort to evaluate the effects of more than two plant population densities or the effects of planting patterns on the yield, yield components and vegetative growth of these hybrids. in 1995, field experiments were conducted at two sites near Montreal to compare the response of leafy reduced-stature (LRS), non-leafy normal stature (NLNS), and non-leafy reduced-stature (NLRS) maize hybrids to plant population densities and planting patterns. LRS maize hybrids showed the most rapid growth of the first ear, and the highest yield per single plant and per hectare at high plant population densities in paired rows. LRS hybrids also had longer grain filling periods, lower grain moisture contents and higher harvest indices than conventional (NLNS) hybrids. Rapid growth of the first ear and a higher harvest index are indications that LRS hybrids should be more tolerant of higher population densities than currently available hybrids. Therefore, LRS hybrids show promise for production in short-season areas at high plant population densities where maize cultivation is not currently economical due to shortness of the growing-season.
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Albuquerque, Fernando Alves de. "Comportamento e dano de tripes na cultura do milho (Zea mays L.) /." Botucatu : [s.n.], 2004. http://hdl.handle.net/11449/105422.
Full textAbstract:
Orientador: Wilson Badiali CrocomoBanca: Carlos Gilberto Raetano
Banca: Adriana Mascarette Labinas
Banca: Ronaldo Pavarini
Banca: Paulo Sérgio Machado Botelho
Resumo: Com o objetivo de identificar as possíveis espécies de tripes associadas à cultura do milho, a espécie predominante, a proporção de adultos e ninfas, a época de ocor-rência, o período crítico de ataque e a influência do sistema de plantio e das condições climáti-cas sobre a população de tripes e métodos de amostragem, foram conduzidos ensaios na Fa-zenda Experimental de Iguatemi, localizada no Município de Maringá, PR, no período de ou-tubro de 2001 a fevereiro de 2004. As avaliações foram realizadas por meio da coleta de tri-pes com armadilhas adesivas azuis e coletando-se plantas de milho, cortadas rente ao solo, colocadas em sacos plásticos e levadas ao laboratório, onde foram lavadas em álcool 70%, para extração dos tripes. A determinação dos danos provocados pelo tripes foi estudada em cinco experimentos inteiramente casualizados, correlacionando diferentes níveis populacionais de tripes e produtividade. Foi empregado o inseticida thiamethoxan, em tratamento de semen-tes, e pulverizações com metamidofós, em diferentes estágios de desenvolvimento das plantas, para obter parcelas com diferentes níveis de incidência de tripes em períodos pré-determinados. Foram identificadas oito espécies de tripes associadas à cultura do milho, na região, sendo Frankliniella williamsi Hood, 1915, a mais freqüente (99,43%). Verificou-se que a incidência de tripes na cultura de milho em solo coberto com aveia dessecada foi menor do que em solo nu, ou coberto por aveia tombada ou incorporada, sendo que imediatamente após a emergência das plantas a população de tripes era composta quase que exclusivamente por adultos imigrantes. A população de formas jovens começou a aumentar a partir dos 14 dias após a emergência das plantas, indicando a capacidade reprodutiva do tripes na cultura do milho. Foi verificada correlação negativa entre... (Resumo completo, clicar acesso eletrônico abaixo).
Abstract: Aiming to identify the possible species of thrips associated to the corn crop, the predominant species, the adult/nymph rate, occurrence time, critical period of attack, influence of the sowing system and climatic conditions on the population of thrips and sampling methods, essays were carried out at the Experimental Farm of Iguatemi, in Maringá, Paraná State, Brazil, from October 2001 to February 2004. The evaluations consisted in collecting thrips with blue adhesive traps and collecting corn plants cuted at soil level, placed into plastic bags and took to the laboratory, where they were washed in alcohol 70%, for the extraction of thrips. The determination of the damages caused by thrips was studied in five experiments, totally randomized, correlating different population levels of thrips and productivity. The insecticide thiamethoxan was applied in seed treatment and methamidophos, in sprayings in different stages of plant development to obtain areas with different levels of incidence of thrips in periods previously established. Eight species of thrips associated to corn crop were identified in the area, being Frankliniella williamsi Hood, 1915, the most frequent (99.43%). It was verified that the incidence of corn thrips in soil covered with dried oats was smaller than in nude soil or in soils covered by cuted or incorporated oat, considering that, immediately after the plants emergence, the population of thrips was composed almost exclusively by emigrant adults. The young population began to increase from 14 days after plant emergence, on indicating thrips reproductivity capacity in corn crops. Negative correlation was verified between the rainfall index and the number of thrips collected in blue traps, but it was not observed any correlation among the number of thrips by corn plant and the number of thrips collected in those traps. It was verified that more than 30 thrips... (Complete abstract, click electronic address below).
Doutor
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Seaman, Kimberly Ann. "Impact of crop-management history on organically fertilized sweet corn (zea mays L.)." [Gainesville, Fla.] : University of Florida, 2005. http://purl.fcla.edu/fcla/etd/UFE0010525.
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Dong, Naiyuan. "Adaptation of Quality Protein Maize (Zea Mays L.) to Northern U.S. Corn Belt." Diss., North Dakota State University, 2015. http://hdl.handle.net/10365/25180.
Full textAbstract:
There is a need to increase the value of crops and develop the next generation of healthier
products. Quality protein maize (Zea mays L.) is an option but has never been adapted to short ?
season environments. Quality protein maize (QPM) with homozygous embryo and endosperm
for mutant allele o2 at the ?-zeins regulatory gene opaque-2 shows about 60 to 100% increase in
lysine and tryptophan essential amino acids when comparing with non-QPM maize. The
objectives of this research were to adapt QPM genotypes to the northern U.S. through the NDSU
Early QPM Program, and to evaluate the agronomic potential of early generation QPM lines and
hybrids developed by the NDSU maize breeding program for the northern USA. Fifty-four
inbred lines, including 47 QPM donor lines from the Iowa State University (ISU) maize breeding
program, six experimental lines from the NDSU maize breeding program and one ex-PVP line
from industry, were selected to produce 94 early-QPM backcross populations. Based on the
earliness, protein content, and amino acid levels of lysine, 218 BC1S2 lines were selected for
testcrosses with industry testers. Experiments evaluating testcrosses were arranged in 12 x 12
and 10 x 10 partially balanced lattice designs across three environments in 2013 and 2014. Based
on this evaluation, totally 48 S2 lines were selected for further development, 17 of them
representing the Stiff Stalk (SS) heterotic group and 31 representing the non-SS-group. Selected
lines provided unique advanced inbred lines with hybrid combinations showing not only above
average grain yield, dry down, and protein content but also, high levels of lysine, tryptophan, and
methionine. The results of this research show, for the first time, the successful adaptation of
QPM genotypes to short-season environments. The NDSU maize-breeding program has
developed the first high quality maize products through the EarlyQPM and EarlyQPMF (for
feedstock) national programs.North Dakota Corn Growers Association
Minnesota Corn Growers Association
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Kabir, Md Zahangir. "Dynamics of mycorrhizal association in corn (Zea mays L.) : influence of tillage and manure." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape15/PQDD_0006/NQ30305.pdf.
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Russell, Elizabeth F. (Elizabeth Fiona). "Influence of ammonium lignosulfonate fertilizer mixtures on corn (Zea mays L.) growth and nutrient composition." Thesis, McGill University, 1992. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=61168.
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Fertilizer P fixation and fertilizer N losses in soils may be reduced through additions of polyphenolic compounds. The influence of ammonium lignosulfonate (NH$ sb4 sp+$-LS) on triple superphosphate (TSP) efficiency was investigated in a soil incubation study using three Quebec soils and in a growth bench study using one soil. For the incubation study, soils were analyzed for pH and P extractability, as a function of NH$ sb4 sp+$-LS rate and time. In the growth bench study, TSP and NH$ sb4 sp+$-LS were applied at varying rates and corn (Zea mays L.) dry matter yields and nutrient compositions analyzed. Similar studies were conducted in subsequent growth bench studies, to evaluate combinations of NH$ sb4 sp+$-LS, diammonium phosphate (DAP), and urea on two soils.Ammonium LS increased soluble P levels when applied with TSP. The effect was most significant in fine textured soils, and increased with time. This improved P availability to plants, without affecting growth. The optimum NH$ sb4 sp+$-LS:P$ sb2$O$ sb5$ application ratio was approximately 2.8:1. Ammonium LS did not improve availability of DAP-P in either of the subsequent experiments, nor did it improve urea fertilizer efficiency. Some NH$ sb4 sp+$-LS-urea-DAP formulations did, however, improve corn growth beyond that obtained when only urea and DAP were applied in combination. In nutrient amended soils, applying NH$ sb4 sp+$-LS DAP was detrimental to growth and, for some application rates, reduced nutrient uptake.
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Santos, Paulo Ricardo Alves dos. "Corn consortium with forage: attributes physical soil and productivity." Universidade Federal do CearÃ, 2016. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=17324.
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Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgicoThe intensification of agricultural production systems is increasing in the current agriculture. In this sense, the simultaneous planting forage to grain crops, constitutes an alternative in the intensification of the production system, which can increase or not the productivity of the main crop, and produce straw for mulching. In order to check the occurrence of changes in the physical properties of the soil and in corn yield and dry matter production due to the corn consortium / forage in two sowing dates, this study was conducted in the experimental area of the Department of Agricultural Engineering of the Federal University of CearÃ. The design was used in a randomized block design in a factorial scheme (3x2) + 1 with four replications, totaling 28 experimental units. The treatments consisted of three forages: Brachiaria, Panicum maximum cv. MombaÃa and Crotalaria spectabilis intercropped with maize in two of fodder sowing dates, between the lines of simultaneous sowing maize (season 1 - E1) and corn leading the V4 stage of corn (season 2 - E2), and the control. The results showed that intercropping maize / forage did not interfere in phytotechnical characteristics of corn, nor in productivity, however produced changes in soil physical properties when the day of sowing in season 1. Despite the changes that have occurred in the soil, they were not sufficient to enhance the productivity of maize, which could possibly be related assessments on only one crop cycle. But when the goal was the production of dry straw, it is concluded that fodder Brachiaria brizantha and Mombasa at the time 1 (E1) are recommended
A intensificaÃÃo dos sistemas de produÃÃo agrÃcola à cada vez maior na atual agricultura. Nesse sentido, o plantio simultÃneo de forrageiras com culturas produtoras de grÃos, constitui em uma alternativa na intensificaÃÃo do sistema de produÃÃo, que poderà incrementar ou nÃo a produtividade da cultura principal, alÃm de produzir palha para cobertura do solo. Com o objetivo de verificar a ocorrÃncia de mudanÃas nas propriedades fÃsicas do solo, bem como na produtividade do milho e produÃÃo de matÃria seca em funÃÃo do consÃrcio milho/forrageiras em duas Ãpocas de semeadura, o presente trabalho foi conduzido na Ãrea experimental do Departamento de Engenharia AgrÃcola da Universidade Federal do CearÃ. Foi utilizado o delineamento em blocos ao acaso, no esquema fatorial (3x2) + 1 com quatro repetiÃÃes, totalizando 28 unidades experimentais. Os tratamentos foram constituÃdos por trÃs forrageiras: Brachiaria brizantha, Panicum maximum cv. MombaÃa e CrotalÃria spectabilis consorciadas com o milho em duas Ãpocas de semeadura das forrageiras, na entrelinha do milho simultÃneo a semeadura (Ãpoca 1 â E1) e na entrelinha do milho no estÃdio V4 do milho (Ãpoca 2 â E2), alÃm da testemunha. Os resultados permitiram concluir que a consorciaÃÃo milho/forrageiras nÃo interferiram nas caracterÃsticas fitotÃcnicas do milho, nem tampouco, na produtividade, porÃm proporcionaram modificaÃÃes nas propriedades fÃsicas do solo quando da realizaÃÃo da semeadura na Ãpoca 1. Apesar das modificaÃÃes ocorridas no solo, as mesmas nÃo foram suficientes em incrementar a produtividade do milho, o que possivelmente pode estar relacionado as avaliaÃÃes em apenas um ciclo da cultura. Jà quando o objetivo foi a produÃÃo de matÃria seca de palha, conclui-se que as forrageiras Brachiaria Brizantha e MombaÃa na Ãpoca 1 (E1) sÃo recomendadas
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Lehle, F. R., N. F. Oebker, and M. White. "Stress Induced Leakage of Sugars as an Estimator of Sweet Corn (Zea Mays) Seed Vigor." College of Agriculture, University of Arizona (Tucson, AZ), 1988. http://hdl.handle.net/10150/214149.
Full textAbstract:
The seed vigor of a super-sweet mutant of sweet corn (Sweetie 76) was compared to that of a traditional, non-mutant variety (Jubilee). The inherent seed vigor of a typical super-sweet corn mutant was considerably less than that of a traditional non-mutant variety. Leakage of reducing sugars from sweet corn seeds at a low temperature was not correlated with seed vigor.
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Modarres, Sanavy S. A. M. (Seyed Ali Mohammad). "Leafy reduced-stature maize (Zea mays L.) for mid- to short-season environments : yield, development, and physiological aspects of inbred lines and hybrids." Thesis, McGill University, 1995. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=39966.
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Maize production in short-season environments has at least two critical problems. Firstly, maize grown in short-season areas has lower leaf area indices (LAI) than maize grown in long season areas, due to shorter plant stature and less time for development, which results in reduced leaf number and size. Secondly, in very short-season areas the seasonal thermal-time available may be insufficient to mature grain of current maize hybrids. Therefore development of maize types that accumulate leaf area and mature quickly would increase production of maize in mid- to short-season areas. The leafy (Lfy1) and reduced-stature (rd1) genes make contributions to this end. However, these two genes have not previously been combined. From 1991 to 1993, field experiments were conducted to evaluate the leafy reduced-stature (LRS) inbred lines and hybrids for yield, maturity times and morphological traits, at different planting densities and patterns in Montreal and Ottawa. LRS maize inbred lines showed the most rapid silk extrusion, optimum leaf area development, and rapid growth of the first ear, the highest yield per unit leaf area, and the closest synchronization of pollen shed and silk extrusion at high plant population densities. LRS maize hybrids had the most rapid leaf development, longest grain filling period, lowest grain moisture content at harvest, and highest harvest index. Therefore LRS hybrids should allow an extension into shorter season areas where it can not now be successfully cultivated, and may increase yields in mid- to short season areas where maize is now produced.
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Kgasago, Hans. "Effect of planting dates and densities on yield and yield components of short and ultra-short growth period of maize (Zea mays L.)." Pretoria : [s.n.], 2006. http://upetd.up.ac.za/thesis/available/etd-09202007-163045.
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Singh, Ajay. "Water and nitrogen use efficiency of corn (Zea mays L.) under water table management." Thesis, McGill University, 2013. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=116989.
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Drainage and water table management are essential for crop production in humid regions. Water table management not only increases crop yield, but also reduces nitrate leaching to water bodies. This study investigated the water and nitrogen use efficiency of corn under two water management conditions and three nitrogen fertilizer levels. The sap flow heat balance method was used to measure the daily water uptake of corn, over an extended period of the growing season. The impacts of climate change on grain corn and biomass yield in eastern Canada under tile drained conditions was also evaluated over a 30 year future period (2040 to 2069). The study was conducted at a field scale in 2008 and 2009 at St. Emmanuel, Quebec. The two water management conditions were: conventional drainage (FD), and controlled drainage with subirrigation (CD-SI). The three nitrogen (N) fertilizer treatments (low, medium, and high N) were applied in a strip across three blocks. The seasonal water balance indicated that the plants in the CD-SI plots had more water than required in the wet periods, despite the system automation, while the FD plots exhibited deficit water conditions. Water could be saved in the wet periods by better regulating water supplied by subirrigation. However, in dry years, the CD-SI system increased yield. The grain corn water use efficiency (WUE) for FD plots was 2.49 and 2.46 kg m-3, in 2008 and 2009, respectively. In these years, the grain WUE for CD-SI plots was 2.43 and 2.26 kg m-3. Water management treatments demonstrated significant difference (p < 0.05) in grain yields in 2009, at low and high nitrogen levels. However, at the medium nitrogen level, water management demonstrated no significant effect (p > 0.05) on grain yields. The two water treatments had no effect on the above-ground dry biomass yields in both years. Mean nitrogen use efficiency (NUE) of grain corn and biomass varied from 27 to 99 kg kg-1. Highest NUE (99 kg kg-1) was observed under low N (~120 kg N ha-1) and lowest NUE (41 kg kg-1) occurred in the high N (~260 kg N ha-1). This might be due to higher nitrogen losses due to leaching, residual nitrogen in the soil, and more denitrification in high N plots. The rate of plant water uptake measured by the sap flow method, varied from 3.55 to 5.11 mm d-1 from silking to full dent stage of corn growth. These rates were consistent with ETc calculated by the FAO-56 Penman-Monteith method (3.70 to 5.93 mm d-1) for both years. Although, silking is considered as a critical stage for corn growth, water demand was highest at the milk stage (45.63 to 59.80 mm). Transpiration during this stage constituted 10 to12% of the total water requirement of the corn for the season. The silking to full dent stage accounted for approximately 40% of the total water requirement of the crop. The STICS (JavaStics v1.0) crop model was used to examine the impacts of climate change, under the B1 emissions scenario, on corn yield from 2040-2069. The model was calibrated using 2008 field measured data, and then validated using the 2009 data set. Corn grain yield was underestimated by 1.5 to 2.6 Mg ha-1 for the two years of measurement. Total dry biomass was also underestimated by 0.9 to 2.6 Mg ha-1. Simulations for the B1 emissions scenario using synthetic weather data was run under the same crop conditions as in 2008. Tukey's studentized range (HSD) test of corn grain yield indicated that yields at high and low N, and high and medium N were different at the 95% confidence level. Grain and biomass production from 2040-2069 under B1 emissions scenario responded differently (p < 0.05) for the three N treatments. However, the Mann–Kendall test showed neither increasing nor decreasing trend (MK-stat > - 1.96) at a 95% confidence level.Le drainage et la gestion de la nappe phréatique des parcelles agricoles permet non seulement d'augmenter la production des récoltes, mais aussi de réduire les pertes de nitrates par lessivage, qui contribue à leurs transferts vers les étendues d'eau. Cette étude a examiné l'efficacité d'utilisation de l'eau et de l'azote du maïs grain sous deux conditions de gestion de l'eau et trois niveaux d'application d'azote. Les facteurs climatiques jouent un rôle important dans la production du maïs-grain. Les impacts des changements climatiques sur les projections de maïs-grain et de la production de biomasse en sol drainé ont aussi été évalués pour l'est du Canada pour une période futur de 30 ans (2040 à 2069). L'étude a été accomplie à l'échelle du champ en 2008 et en 2009 à Saint Emmanuel au Québec. Les deux scénarios de gestion de l'eau étaient (a) le drainage conventionnel (FD) et (b) le drainage contrôlé combiné à l'irrigation souterraine (CD-SI). Les trois traitements d'azote (N) (dose faible, moyenne et élevée) ont été appliqués en bande sur trois blocs. L'efficacité d'utilisation de l'eau du maïs (WUE) pour les blocs en FD était de 2.49 kg m-3 et 2.46 kg m-3 en 2008 et 2009 respectivement. Pour ces années, L'WUE du maïs-grain pour les blocs en CD-SI était de 2.43 kg m-3 et de 2.26 kg m-3. Les traitements relatifs à la gestion de l'eau ont permis d'améliorer la production de rendement du maïs-grain significativement (p <0.05) en 2009, que cela soit avec des doses d'azotes basses ou élevées. Cependant, pour des doses intermédiaires, la gestion de l'eau n'a démontré aucun effet significatif (p> 0.05) sur les productions de maïs-grain. Les deux traitements relatifs à la gestion de l'eau n'ont eu aucun effet sur la production de biomasse sèche au-dessus du sol pour les deux années. L'efficacité moyenne de l'utilisation de l'azote (NUE) du maïs grain et de sa biomasse variait de 27 kg kg-1 à 99 kg kg-1. La plus haute NUE (99 kg kg-1) a été observée pour une dose de N faible (~120 kg N ha-1). La plus basse NUE (41 kg kg-1) s'est produite pour une dose de N élevée (~260 kg N ha-1). La consommation des plantes en eau mesurée par la méthode d'écoulement de la sève, vari de 3.55 mm d-1 à 5.11 mm d-1 pour la période de l'apparition des soies jusqu'à la croissance complète du maïs-grain. Ces taux sont en accord avec l'ETc calculée (3.70 mm d-1 à 5.93 mm d-1) pour les deux ans. Bien que, le développement de la soie soit considéré comme le stade critique pour le maïs-grain, la demande en eau fut la plus élevée lors du stade laiteux du développement du maïs (45.63 mm à 59.80 mm). À ce stade, 10 à 12% des besoins totaux de la plante en eau pour la saison furent transpirés. Du stade de la soie jusqu'au développement complet de l'épi de maïs les besoins en eau de la plante ont représenté environ 40 % de son besoin total. Le modèle de récolte STICS (JavaStics v1.0) a été utilisé pour examiner les effets du changement climatique sur la production de maïs- grain, de 2040 à 2069 et sous le scénario d'émissions de gaz à effet de serre B1. Le modèle a d'abord été calibré en utilisant les données mesurées au champ en 2008 et, a ensuite été validé avec l'ensemble des données de 2009. La production de maïs-grain est sous-estimée de 1.5 Mg ha-1 à 2.6 Mg ha-1 pour les deux ans de mesure. La biomasse sèche totale est aussi sous-estimée de 0.9 Mg ha-1 à 2.6 Mg ha-1. Les simulations pour le scénario d'émissions B1 en utilisant des données météorologiques synthétiques font été utilisées dans les mêmes conditions de récolte que 2008. Les prédictions de la production de maïs-grain et de sa biomasse pour la période 2040-2069 sous le scénario d'émissions B1 sont différentes (p <0.05) selon les trois traitements de N. Cependant, l'épreuve de Mann-Kendall n'a montré aucune tendance à la hausse ou à la baisse (MK-stat> - 1.96) pour un niveau de confiance de 95%.
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Battaglia, Martin Leonardo. "CORN (Zea mays L.) YIELD RESPONSE TO DEFOLIATION AT DIFFERENT ROW WIDTHS." UKnowledge, 2014. http://uknowledge.uky.edu/pss_etds/56.
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Corn (Zea mays L.) defoliation experiments have been conducted for more than 120 years. However, there is limited data on the effect of row width on defoliation in modern hybrids. A two-year experiment was conducted in Lexington, Kentucky with two hybrids (113 relative maturity (RM) and 120 RM), two row widths (38 and 76 cm) and a combination of defoliation timings and severities: 0% defoliation (control), V7-100%, V14-50%, V14-100%, R2-50% and R2-100%. No yield difference among hybrids was observed in 2012. Yields were 26% greater in 38-cm rows than 76-cm rows in 2012. For 2013, corn yield for 38-cm was 10% greater, but hybrid, row width and defoliation interacted. Lowest yields were caused by V14-100% followed by R2-100%. Defoliations of V14-50% and R2-50% reduced yields in some cases. Complete defoliations at V7 did not reduce yields in most comparisons. Light interception below 80% during the critical period was enough to attain maximum yields in defoliated plants. Kernel number and kernel weight were most reduced by V14-100% and R2-100% defoliations, respectively. There is a potential for narrow rows to reduce grain yield losses after a defoliation event, when compared with wide rows.
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Martin, Victor Lee. "Drainage, tillage, rotation effects for corn (Zea mays L.) Grown on an aeric fragiaqualf /." The Ohio State University, 1991. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487688973682717.
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Bautista, Marina Caballero. "Processing and conservation of the grain of corn (Zea Mays L.) and project of industrial feasibility." BYU ScholarsArchive, 2001. https://scholarsarchive.byu.edu/etd/5331.
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Since Pre-Colombian time corn already formed part of the diet in Aztec and Mayan cultures, and actually represented in them a fountain of wealth and power. The cultivation is utilized in the region in multiple forms, not only for the human diet, but also as feed for animals. Corn is third place in the world production, following wheat and rice. It is cultivated in a total surface of 106 million hectares, its yield is 215 million tons, that represents an average of 2 tons per hectare. The cultivation of corn has special importance, given that this cereal constitutes the basic food the Latin-Americans. This cereal adapts extensively to diverse ecological conditions. Its high performance and future possibilities of even more improvement through genetics make this cereal one of the plants most promising to confront the threat of hunger in the world. For this reason, it is cultivated in almost every part of the world because of its ample range of elevations. It can grow from sea level to approximately 2500 meters. In the last few years, the world production of corn has grown an average of 3.2% per year, set against 1.1% of semi-annual growth, for surface sown. This difference comes from a strong increase of the average unit yield. This was possible thanks to use of highly productive hybrid corn, with the aid of improve agricultural techniques, such as greater plantation density, more resilient, uses of more effective pesticides and herbicides, etc. In Bolivia, the agriculture area has large potential to develop, but because of political causes not appropriate for our country, and the insufficient economic resources that destines the area to stay rural, these negative aspects are responsible for the backward movement and the misery, making it impossible to develop the agriculture area. The region of Cochabamba, constitutes the main supplier of food. In the country, the economic activity of the valleys are based mainly in agriculture and stockbreeding, being characterized as a growing zone and basically for cereal, whose preferential scale of cultivation is as continues: Corn, wheat, barley, alfalfa, and other. The population of Cochabamba varies because of the growing of corn is only in the seasons of summer and part of the fall, the rest of the time few people stay there. The farmers, to obtain better prices, try to harvest at the start and end of the growing seasons, this is possible when they make a good management of plant's health, irrigation, and soil. etc., due to the smaller effort, the prices are higher, but in the months of February and March is when the effort pays off, because almost all of the farmers harvest, and the prices of this product drops, many times even below the price of production, being consequence of the dry culture. The price of fresh corn on the cob is greater than dry corn. When corn is fresh it has different uses such as humitas, lawas and corn on the cob. El Valle Alta (Punata), the farmers do not market their produce in the markets, despite of the small farms of the area, for this cause merchants truckers exist that gather the produce of all the farmers, and take the majority of the profits, which is why it is necessary for industrialization of the agricultural production. The vegetables are directly or indirectly the source of all the food, because they are capable of using solar energy and to carry out diverse chemical synthesis, that cannot be performed by animals. The principles of the same they are photosynthesis, which consists of the application of the solar energy, to synthesize carbohydrates, and the fixation of nitrogen, which is the foundation for the synthesis of the proteins. The vegetables most consumed are the cereals, legumes, and tubers, they constitute the basic diet. The word ""vegetable"" includes an extensive range of vegetables, and the majority of the vegetables contain at most 60%-80% of the water.
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Fu, Yibing. "Pattern of genomic loci controlling morphological responses to UV-B radiation in maize (Zea mays L.) /." Electronic version (PDF), 2004. http://dl.uncw.edu/etd/2004/fuy/yibingfu.pdf.
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Armour, Ian. "Intercropping corn (Zea mays L.) with forage legumes to suppress yellow nutsedge (Cyperus esculentus L.)." Thesis, McGill University, 1989. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=59300.
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A two year study was conducted to investigate the effect of intercropping corn with alfalfa or red clover with or without an initial application of the herbicide EPTC$ sp+$ (S-ethyl dipropylthiocarbamate + R-25788 antidote) on the weed yellow nutsedge (Cyperus esculentus L.). EPTC$ sp+$ applied prior to crop seeding in 1984 significantly reduced yellow nutsedge shoot growth in the first year but did not significantly reduce tuber populations. EPTC$ sp+$ significantly improved corn silage and grain yield and alfalfa establishment in the first year but did not significantly improve red clover establishment. In the second year, a trend of superior forage legume establishment and lower yellow nutsedge shoot production was observed in those treatments established the previous year with EPTC$ sp+$. Over the two year period, yellow nutsedge tuber populations in treatments established with EPTC$ sp+$ were significantly greater in the monocropped corn treatment than in any other treatment. In treatments established without a herbicide, yellow nutsedge tuber populations were also greatest in the monocropped corn treatment.
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Mueting, Sara Ann. "FATE, TRANSPORT, AND MIXTURE TOXICITY OF TRANSGENIC BACILLUS THURINGIENSIS CORN (ZEA MAYS) AND ASSOCIATED INSECTICIDES." OpenSIUC, 2014. https://opensiuc.lib.siu.edu/dissertations/842.
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Corn is a dominating feature in the landscape of the Midwestern United States. Associated with this crop are a plethora of products from fertilizers to pesticides that help farmers maximize grain yield while minimizing costs. A widely accepted form of protection from major pests in the United States is genetically modified corn that has been altered so that it contains genetic material from another species, a soil bacterium, Bacillus thuringiensis Berliner (Bt corn), in order to produce proteins that are toxic to some insect pests. Additional insecticides that are commonly used to protect corn include a neonicotinoid seed coating, clothianidin, and a pyrethroid insecticide applied in-furrow, tefluthrin. The goal of my dissertation was to measure the environmental fate of the Cry1Ab Bt corn protein, clothianidin, and tefluthrin and determine if measured concentrations could be causing effects to non-target species. The Cry1Ab proteins persisted only during the corn growing season in soil, runoff water and sediment with the highest concentrations measured during pollination. Clothianidin was detected in all matrices and remained persistent throughout the year in soil pore water. Tefluthrin was consistently detected in soil, runoff water, and runoff sediment during the corn growing season, but was not found in groundwater or soil pore water. No acute toxicity was observed to any species when exposed to the Cry1Ab protein in corn plant leaf tissue, therefore little risk was anticipated. Non-target species exposed to clothianidin resulted in limited ecological risk from field exposures. Tefluthrin results indicated elevated risk for non-target species exposed to tefluthrin at concentrations that were measured in the field study. There was no increase in toxicity to tefluthrin when non-target species were exposed to a combination of all three insecticides. In summary, the genetically modified corn insecticidal proteins and clothianidin were not found at environmental concentrations exceeding benchmark values for ecological effects, but tefluthrin was consistently detected in the environment at levels that could be causing toxicity to non-target species, especially if it is able to travel off-site.
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Sforza, Peter M. "Investigation of Biotic and Abiotic Factors Affecting Double-Cropped Corn (Zea mays L.) Production in Virginia." Thesis, Virginia Tech, 2004. http://hdl.handle.net/10919/35053.
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Double-cropping of corn (Zea mays L.) for grain following the harvest of a small grain crop has been under evaluation in Virginia as an alternative cropping strategy (Brann and Pitman, 1997). To assess the potential constraints on late planted corn imposed by insects and diseases, double-cropped corn was evaluated in field experiments in Montgomery County, Virginia from 1998 to 2000. Factors included two near-isoline hybrids (NK4640 and NK4640Bt), insecticides at planting (tefluthrin in all years, 1998-2000; and imidacloprid in 1999 and 2000), and fungicide treatments (azoxystrobin or propiconazole). Response variables included yield, moisture at harvest, grain test weight, damage by European corn borer (Ostrinia nubilalis), damage by corn earworm (Heliothis zea), disease progress curves for gray leaf spot Cercospora zeae-maydis), and number of plants exhibiting virus symptoms. The Bt hybrid performed significantly better than the non-Bt hybrid for yield and test weight in double-cropped corn in 1998 and 2000, but not in 1999. A spatially referenced site suitability analysis was performed for full season and double-cropped corn in Virginia using weighted abiotic factors and constraints. Thornthwaite potential evapotranspiration (PET) and PET minus precipitation were used to identify areas of the state having a lower average moisture deficit during the silking months for double-cropped corn compared to full-season corn. It is concluded that double-cropped corn production is a viable option in Virginia where abiotic factors are not constraining, particularly growing season length and moisture availability during the sensitive stages of development.Master of Science
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Malhotra, Divya. "brk1 and dcd1 Act Synergistically in Subsidiary Cell Formation in Zea mays." Thesis, University of North Texas, 2014. https://digital.library.unt.edu/ark:/67531/metadc799473/.
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Subsidiary mother cell (SMC) divisions during stomatal complex formation in Zea mays are asymmetric generating a small subsidiary cell (SC) and a larger epidermal cell. Mutants with a high number of abnormally shaped subsidiary cells include the brick1 (brk1) and discordia1 (dcd1) mutants. BRK1 is homologous to HSPC300, an ARP2/3 complex activator, and is involved in actin nucleation while DCD1 is a regulatory subunit of the PP2A phosphatase needed for microtubule generation (Frank and Smith, 2002; Wright et al. 2009). Possible causes of the abnormal SCs in brk1 mutants include a failure of the SMC nucleus to polarize in advance of mitosis, no actin patch, and transverse and/or no PPBs (Gallagher and Smith, 2000; Panteris et al 2006). The abnormal subsidiary mother cell division in dcd1 is due to correctly localized, but disorganized preprophase bands (PPBs; Wright et al. 2009). The observation that brk1 has defects in PPB formation and that the dcd1 phenotype is enhanced by the application of actin inhibitors led us to examine the dcd1; brk1 double mutant (Gallagher and Smith, 1999). We found that dcd1; brk1 double mutants demonstrate a higher percentage of aberrant SCs than the single mutants combined suggesting that these two mutations have a synergistic and additive effect on SC formation. Our observations and results are intriguing and the future step will be to quantitate the abnormal PPBs and phragmoplasts in the double and single mutants using immunolocalization of tubulin and actin as well as observations of live cells expressing tubulin-YFP.
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Alodailah, Sattam Sonitan. "The Generation of Recombinant Zea mays Spastin and Katanin Proteins for In Vitro Analysis." Thesis, University of North Texas, 2017. https://digital.library.unt.edu/ark:/67531/metadc1062897/.
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Plant microtubules play essential roles in cell processes such as cell division, cell elongation, and organelle organization. Microtubules are arranged in highly dynamic and ordered arrays, but unlike animal cells, plant cells lack centrosomes. Therefore, microtubule nucleation and organization are governed by microtubule-associated proteins, including a microtubule-severing protein, katanin. Mutant analysis and in vitro characterization has shown that the highly conserved katanin is needed for the organization of the microtubule arrays in Arabidopsis and rice as well as in a variety of animal models. Katanin is a protein complex that is part of the AAA+ family of ATPases. Katanin is composed of two subunits, katanin-p60, a catalytic subunit and katanin-p80, a regulatory subunit. Spastin is another MT-severing protein that was identified on the basis of its homology to katanin. In animal cells, spastin is also needed for microtubule organization, but its functionality has not yet been investigated in plants. To initiate an exploration of the function of katanin-p60 and spastin in Zea mays, my research goal was to generate tools for the expression and purification of maize katanin-p60 and spastin proteins in vitro. Plasmids that express katanin-p60 and spastin with N-terminal GST tags were designed and constructed via In-Fusion® cloning after traditional cloning methods were not successful. The constructs were expressed in E. coli, then the recombinant proteins were purified. To determine if the GST-tagged proteins are functional, ATPase activity and tubulin polymerization assays were performed. While both GST-katanin-p60 and GST-spastin hydrolyzed ATP indicating that the ATPase domains are functional, the results of the tubulin polymerization assays were less clear and further experimentation is necessary.
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Gagnon, Diane C. "Neem products for the control of the European corn borer, Ostrinia nubilalis (Hubner), in sweet corn, Zea mays (L.)." Thesis, University of Ottawa (Canada), 1992. http://hdl.handle.net/10393/7703.
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The use of neem products to control the European corn borer, Ostrinia nubilalis (Hubner), in sweet corn was investigated. Three years of field studies were conducted comparing various foliar-spray applications of a neem seed kernel extract (NSKE), azadirachtin (AZA, the active ingredient of neem extracts), and Ambush (a synthetic pyrethroid). The results included: (1) NSKE sprayed prior to artificial infestation of the corn plants provided excellent protection (comparable to Ambush) against borer damage and greatly reduced larval populations. (2) Neem extract formulations from Safer Ltd. were the most effective. (3) The rate of application or number of applications were not determining factors in altering the efficacy of neem products. (4) Exceptional weather conditions (high temperatures, dry conditions) may be detrimental to the efficacy of foliar applied neem products. (5) Some neem treatments were found to increase corn stalk breakage possibly by altering the behavior of the larvae. Laboratory evaluations using no-choice leaf-disk bioassays showed the antifeedant action of AZA and the negligible effect of PBO (piperonyl butoxide) and Citowett (used in field formulations) on the feeding behavior of 3rd instar larvae. Growth and development studies of O. nubilalis fed a diet containing 0, 1, 3, 10, 30, 100, and 1000 $\mu$g NSKE g$\sp{-1}$ diet were conducted. 10 $\mu$g NSKE g$\sp{-1}$ diet (50 ng AZA g$\sp{-1}$ diet) fed continuously to the larvae were larvicidal and concentrations as low as 3 $\mu$g NSKE g$\sp{-1}$ diet (16.6 ng AZA g$\sp{-1}$ diet) significantly reduced larval, pupal and adult weights, increased the larval and pupal periods, decreased adult emergence and caused wing deformities. AZA content of the extracts was found to be a critical factor in the IGR (insect growth regulator) effects of NSKE. (Abstract shortened by UMI.)
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Thobatsi, Jacob Thobatsi. "Growth and yield responses of maize (Zea mays L.) and cowpea (Vigna unguiculata L.) in an intercropping system." Diss., Pretoria : [s.n.], 2009. http://upetd.up.ac.za/thesis/available/etd-10122009-184005.
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Fan, Mingxiang. "Urea and acidic phosphate interactions in fertilizer microsites and their effect on corn (Zea mays L.) yield and nutrient use efficiency." Thesis, McGill University, 1993. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=41334.
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Fertilizer applications of urea and triple superphosphate (TSP) suffer from low efficiency for corn production. Band or broadcast application of urea with acidic-P fertilizers may increase fertilizer efficiency. Urea and acidic-P fertilizer interactions in soil-fertilizer microsites were investigated using two Quebec soils. Adding acidic phosphates such as TSP and monoammonium phosphate (MAP) to urea reduced pH in microsites, urea hydrolysis, NH$ sb3$ volatilization, and increased soil NH$ sb4$- and NO$ sb3$-N contents. Ammonia loss decreased as P$ rm sb2O sb5$: urea-N ratios increased. Adding urea to P fertilizer increased soil pH and P sorption when using CaCl$ sb2$ as the electrolyte. Urea application increased 0.5 M NaHCO$ sb3$ extractable P. Banding urea with TSP caused dissolution of organic matter in soils, and increased P diffusion and P concentration in soil solution sampled with filter paper or in 1 M KCl extraction. Two years of field experiments demonstrated that banding urea with TSP or MAP increased soil extractable P (Mehlich-3), N and P nutrient uptake, plant growth and development of corn. Greater P fertilizer efficiencies and higher yields were achieved by banding urea-acidic P fertilizers.